CMP Journal 2025-04-09
Statistics
Nature: 40
Nature Materials: 2
Physical Review Letters: 4
Physical Review X: 2
arXiv: 70
Nature
Towards accurate differential diagnosis with large language models
Original Paper | Diagnosis | 2025-04-08 20:00 EDT
Daniel McDuff, Mike Schaekermann, Tao Tu, Anil Palepu, Amy Wang, Jake Garrison, Karan Singhal, Yash Sharma, Shekoofeh Azizi, Kavita Kulkarni, Le Hou, Yong Cheng, Yun Liu, S. Sara Mahdavi, Sushant Prakash, Anupam Pathak, Christopher Semturs, Shwetak Patel, Dale R. Webster, Ewa Dominowska, Juraj Gottweis, Joelle Barral, Katherine Chou, Greg S. Corrado, Yossi Matias, Jake Sunshine, Alan Karthikesalingam, Vivek Natarajan
A comprehensive differential diagnosis is a cornerstone of medical care that is often reached through an iterative process of interpretation that combines clinical history, physical examination, investigations and procedures. Interactive interfaces powered by large language models present new opportunities to assist and automate aspects of this process1. Here we introduce the Articulate Medical Intelligence Explorer (AMIE), a large language model that is optimized for diagnostic reasoning, and evaluate its ability to generate a differential diagnosis alone or as an aid to clinicians. Twenty clinicians evaluated 302 challenging, real-world medical cases sourced from published case reports. Each case report was read by two clinicians, who were randomized to one of two assistive conditions: assistance from search engines and standard medical resources; or assistance from AMIE in addition to these tools. All clinicians provided a baseline, unassisted differential diagnosis prior to using the respective assistive tools. AMIE exhibited standalone performance that exceeded that of unassisted clinicians (top-10 accuracy 59.1% versus 33.6%, P = 0.04). Comparing the two assisted study arms, the differential diagnosis quality score was higher for clinicians assisted by AMIE (top-10 accuracy 51.7%) compared with clinicians without its assistance (36.1%; McNemar’s test: 45.7, P < 0.01) and clinicians with search (44.4%; McNemar’s test: 4.75, P = 0.03). Further, clinicians assisted by AMIE arrived at more comprehensive differential lists than those without assistance from AMIE. Our study suggests that AMIE has potential to improve clinicians’ diagnostic reasoning and accuracy in challenging cases, meriting further real-world evaluation for its ability to empower physicians and widen patients’ access to specialist-level expertise.
Diagnosis, Medical research
Connectomics of predicted Sst transcriptomic types in mouse visual cortex
Original Paper | Cellular neuroscience | 2025-04-08 20:00 EDT
Clare R. Gamlin, Casey M. Schneider-Mizell, Matthew Mallory, Leila Elabbady, Nathan Gouwens, Grace Williams, Alice Mukora, Rachel Dalley, Agnes L. Bodor, Derrick Brittain, JoAnn Buchanan, Daniel J. Bumbarger, Emily Joyce, Daniel Kapner, Sam Kinn, Gayathri Mahalingam, Sharmishtaa Seshamani, Marc Takeno, Russel Torres, Wenjing Yin, Philip R. Nicovich, J. Alexander Bae, Manuel A. Castro, Sven Dorkenwald, Akhilesh Halageri, Zhen Jia, Chris Jordan, Nico Kemnitz, Kisuk Lee, Kai Li, Ran Lu, Thomas Macrina, Eric Mitchell, Shanka Subhra Mondal, Shang Mu, Barak Nehoran, Sergiy Popovych, William Silversmith, Nicholas L. Turner, William Wong, Jingpeng Wu, Szi-chieh Yu, Jim Berg, Tim Jarsky, Brian Lee, H. Sebastian Seung, Hongkui Zeng, R. Clay Reid, Forrest Collman, Nuno Maçarico da Costa, Staci A. Sorensen
Neural circuit function is shaped both by the cell types that comprise the circuit and the connections between them1. Neural cell types have previously been defined by morphology2,3, electrophysiology4, transcriptomic expression5,6, connectivity7,8,9 or a combination of such modalities10,11,12. The Patch-seq technique enables the characterization of morphology, electrophysiology and transcriptomic properties from individual cells13,14,15. These properties were integrated to define 28 inhibitory, morpho-electric-transcriptomic (MET) cell types in mouse visual cortex16, which do not include synaptic connectivity. Conversely, large-scale electron microscopy (EM) enables morphological reconstruction and a near-complete description of a neuron’s local synaptic connectivity, but does not include transcriptomic or electrophysiological information. Here, we leveraged morphological information from Patch-seq to predict the transcriptomically defined cell subclass and/or MET-type of inhibitory neurons within a large-scale EM dataset. We further analysed Martinotti cells–a somatostatin (Sst)-positive17 morphological cell type18,19–which were classified successfully into Sst MET-types with distinct axon myelination and synaptic output connectivity patterns. We demonstrate that morphological features can be used to link cell types across experimental modalities, enabling further comparison of connectivity to gene expression and electrophysiology. We observe unique connectivity rules for predicted Sst cell types.
Cellular neuroscience, Neuroscience
Ultra-broadband optical amplification using nonlinear integrated waveguides
Original Paper | Nonlinear optics | 2025-04-08 20:00 EDT
Ping Zhao, Vijay Shekhawat, Marcello Girardi, Zonglong He, Victor Torres-Company, Peter A. Andrekson
Four-wave mixing is a nonlinear optical phenomenon that can be used for wideband low-noise optical amplification and wavelength conversion. It has been extensively investigated for applications in communications1, computing2, metrology3, imaging4 and quantum optics5. With its advantages of small footprint, large nonlinearity and dispersion-engineering capability, optical integrated waveguides are excellent candidates for realizing high-gain and large-bandwidth four-wave mixing for which anomalous dispersion is a key condition. Various waveguides based on, for example, silicon, aluminium gallium arsenide and nonlinear glass have been studied6,7,8,9,10, but suffer from considerable gain and bandwidth reductions, as conventional design approaches for anomalous dispersion result in multi-mode operation. We present a methodology for fabricating nonlinear waveguides with simultaneous single-mode operation and anomalous dispersion for ultra-broadband operation and high-efficiency four-wave mixing. Although we implemented this in silicon nitride waveguides, the design approach can be used with other platforms as well. By using higher-order dispersion, we achieved unprecedented amplification bandwidths of more than 300 nm in these ultra-low-loss integrated waveguides. Penalty-free all-optical wavelength conversion of 100 Gbit s-1 data in a single optical channel of over 200 nm was realized. These single-mode dispersion-engineered nonlinear waveguides could become practical building blocks in various nonlinear photonics applications.
Nonlinear optics, Silicon photonics
Immune checkpoint TIM-3 regulates microglia and Alzheimer’s disease
Original Paper | Microglial cells | 2025-04-08 20:00 EDT
Kimitoshi Kimura, Ayshwarya Subramanian, Zhuoran Yin, Ahad Khalilnezhad, Yufan Wu, Danyang He, Karen O. Dixon, Udbhav Kasyap Chitta, Xiaokai Ding, Niraj Adhikari, Isabell Guzchenko, Xiaoming Zhang, Ruihan Tang, Thomas Pertel, Samuel A. Myers, Aastha Aastha, Masashi Nomura, Ghazaleh Eskandari-Sedighi, Vasundhara Singh, Lei Liu, Conner Lambden, Kilian L. Kleemann, Neha Gupta, Jen-Li Barry, Ana Durao, Yiran Cheng, Sebastian Silveira, Huiyuan Zhang, Aamir Suhail, Toni Delorey, Orit Rozenblatt-Rosen, Gordon J. Freeman, Dennis J. Selkoe, Howard L. Weiner, Mathew Blurton-Jones, Carlos Cruchaga, Aviv Regev, Mario L. Suvà, Oleg Butovsky, Vijay K. Kuchroo
Microglia are the resident immune cells in the brain and have pivotal roles in neurodevelopment and neuroinflammation1,2. This study investigates the function of the immune-checkpoint molecule TIM-3 (encoded by HAVCR2) in microglia. TIM-3 was recently identified as a genetic risk factor for late-onset Alzheimer’s disease3, and it can induce T cell exhaustion4. However, its specific function in brain microglia remains unclear. We demonstrate in mouse models that TGFβ signalling induces TIM-3 expression in microglia. In turn, TIM-3 interacts with SMAD2 and TGFBR2 through its carboxy-terminal tail, which enhances TGFβ signalling by promoting TGFBR-mediated SMAD2 phosphorylation, and this process maintains microglial homeostasis. Genetic deletion of Havcr2 in microglia leads to increased phagocytic activity and a gene-expression profile consistent with the neurodegenerative microglial phenotype (MGnD), also referred to as disease-associated microglia (DAM). Furthermore, microglia-targeted deletion of Havcr2 ameliorates cognitive impairment and reduces amyloid-β pathology in 5×FAD mice (a transgenic model of Alzheimer’s disease). Single-nucleus RNA sequencing revealed a subpopulation of MGnD microglia in Havcr2-deficient 5×FAD mice characterized by increased pro-phagocytic and anti-inflammatory gene expression alongside reduced pro-inflammatory gene expression. These transcriptomic changes were corroborated by single-cell RNA sequencing data across most microglial clusters in Havcr2-deficient 5×FAD mice. Our findings reveal that TIM-3 mediates microglia homeostasis through TGFβ signalling and highlight the therapeutic potential of targeting microglial TIM-3 in Alzheimer’s disease.
Microglial cells, Neuroimmunology
Active energy compression of a laser-plasma electron beam
Original Paper | High-field lasers | 2025-04-08 20:00 EDT
P. Winkler, M. Trunk, L. Hübner, A. Martinez de la Ossa, S. Jalas, M. Kirchen, I. Agapov, S. A. Antipov, R. Brinkmann, T. Eichner, A. Ferran Pousa, T. Hülsenbusch, G. Palmer, M. Schnepp, K. Schubert, M. Thévenet, P. A. Walker, C. Werle, W. P. Leemans, A. R. Maier
Radio-frequency (RF) accelerators providing high-quality relativistic electron beams are an important resource enabling many areas of science, as well as industrial and medical applications. Two decades ago, laser-plasma accelerators1 that support orders of magnitude higher electric fields than those provided by modern RF cavities produced quasi-monoenergetic electron beams for the first time2,3,4. Since then, high-brightness electron beams at gigaelectronvolt (GeV) beam energy and competitive beam properties have been demonstrated from only centimetre-long plasmas5,6,7,8,9, a substantial advantage over the hundreds of metres required by RF-cavity-based accelerators. However, despite the considerable progress, the comparably large energy spread and the fluctuation (jitter) in beam energy still effectively prevent laser-plasma accelerators from driving real-world applications. Here we report the generation of a laser-plasma electron beam using active energy compression, resulting in a performance so far only associated with modern RF-based accelerators. Using a magnetic chicane, the electron bunch is first stretched longitudinally to imprint an energy correlation, which is then removed with an active RF cavity. The resulting energy spread and energy jitter are reduced by more than an order of magnitude to below the permille level, meeting the acceptance criteria of a modern synchrotron, thereby opening the path to a compact storage ring injector and other applications.
High-field lasers, Plasma-based accelerators
Swinging lever mechanism of myosin directly shown by time-resolved cryo-EM
Original Paper | Contractile proteins | 2025-04-08 20:00 EDT
David P. Klebl, Sean N. McMillan, Cristina Risi, Eva Forgacs, Betty Virok, Jennifer L. Atherton, Sarah A. Harris, Michele Stofella, Donald A. Winkelmann, Frank Sobott, Vitold E. Galkin, Peter J. Knight, Stephen P. Muench, Charlotte A. Scarff, Howard D. White
Myosins produce force and movement in cells through interactions with F-actin1. Generation of movement is thought to arise through actin-catalysed conversion of myosin from an ATP-generated primed (pre-powerstroke) state to a post-powerstroke state, accompanied by myosin lever swing2,3. However, the initial, primed actomyosin state has never been observed, and the mechanism by which actin catalyses myosin ATPase activity is unclear. Here, to address these issues, we performed time-resolved cryogenic electron microscopy (cryo-EM)4 of a myosin-5 mutant having slow hydrolysis product release5,6. Primed actomyosin was predominantly captured 10 ms after mixing primed myosin with F-actin, whereas post-powerstroke actomyosin predominated at 120 ms, with no abundant intermediate states detected. For detailed interpretation, cryo-EM maps were fitted with pseudo-atomic models. Small but critical changes accompany the primed motor binding to actin through its lower 50-kDa subdomain, with the actin-binding cleft open and phosphate release prohibited. Amino-terminal actin interactions with myosin promote rotation of the upper 50-kDa subdomain, closing the actin-binding cleft, and enabling phosphate release. The formation of interactions between the upper 50-kDa subdomain and actin creates the strong-binding interface needed for effective force production. The myosin-5 lever swings through 93°, predominantly along the actin axis, with little twisting. The magnitude of lever swing matches the typical step length of myosin-5 along actin7. These time-resolved structures demonstrate the swinging lever mechanism, elucidate structural transitions of the power stroke, and resolve decades of conjecture on how myosins generate movement.
Contractile proteins, Cryoelectron microscopy
Foundation model of neural activity predicts response to new stimulus types
Original Paper | Computational models | 2025-04-08 20:00 EDT
Eric Y. Wang, Paul G. Fahey, Zhuokun Ding, Stelios Papadopoulos, Kayla Ponder, Marissa A. Weis, Andersen Chang, Taliah Muhammad, Saumil Patel, Zhiwei Ding, Dat Tran, Jiakun Fu, Casey M. Schneider-Mizell, Nuno Maçarico da Costa, R. Clay Reid, Forrest Collman, Nuno Maçarico da Costa, Katrin Franke, Alexander S. Ecker, Jacob Reimer, Xaq Pitkow, Fabian H. Sinz, Andreas S. Tolias
The complexity of neural circuits makes it challenging to decipher the brain’s algorithms of intelligence. Recent breakthroughs in deep learning have produced models that accurately simulate brain activity, enhancing our understanding of the brain’s computational objectives and neural coding. However, it is difficult for such models to generalize beyond their training distribution, limiting their utility. The emergence of foundation models1 trained on vast datasets has introduced a new artificial intelligence paradigm with remarkable generalization capabilities. Here we collected large amounts of neural activity from visual cortices of multiple mice and trained a foundation model to accurately predict neuronal responses to arbitrary natural videos. This model generalized to new mice with minimal training and successfully predicted responses across various new stimulus domains, such as coherent motion and noise patterns. Beyond neural response prediction, the model also accurately predicted anatomical cell types, dendritic features and neuronal connectivity within the MICrONS functional connectomics dataset2. Our work is a crucial step towards building foundation models of the brain. As neuroscience accumulates larger, multimodal datasets, foundation models will reveal statistical regularities, enable rapid adaptation to new tasks and accelerate research.
Computational models, Extrastriate cortex, Machine learning, Network models, Sensory processing
Leaf absorption contributes to accumulation of microplastics in plants
Original Paper | Environmental monitoring | 2025-04-08 20:00 EDT
Ye Li, Junjie Zhang, Li Xu, Ruoqi Li, Rui Zhang, Mengxi Li, Chunmei Ran, Ziyu Rao, Xing Wei, Mingli Chen, Lu Wang, Zhiwanxin Li, Yining Xue, Chu Peng, Chunguang Liu, Hongwen Sun, Baoshan Xing, Lei Wang
Plant absorption is important for the entry of many pollutants into food chains. Although terrestrial microplastics (MPs) can be absorbed by the roots1,2, their upward translocation is slow1. Meanwhile, atmospheric MPs are widely present3,4, but strong evidence on their direct absorption by plants is still lacking. Here, analyses using mass spectrometry detection show the widespread occurrence of polyethylene terephthalate (PET) and polystyrene (PS) polymers and oligomers in plant leaves, and identify that their levels increase with atmospheric concentrations and the leaf growth duration. The concentrations of PET and PS polymers can reach up to 104 ng per g dry weight in leaves at the high-pollution areas studied, such as the Dacron factory and a landfill site, and 102-103 ng per g dry weight of PET and PS can be detected in the open-air-grown leafy vegetables. Nano-sized PET and PS particles in the leaves were visually detected by hyperspectral imaging and atomic force microscopy-infrared spectroscopy. Absorption of the proactively exposed non-labelled, fluorescently labelled or europium-labelled plastic particles by maize (Zea mays L.) leaves through stomatal pathways, as well as their translocation to the vascular tissue through the apoplastic pathway, and accumulation in trichomes was identified using hyperspectral imaging, confocal microscopy and laser-ablation inductively coupled plasma mass spectrometry. Our results demonstrate that the absorption and accumulation of atmospheric MPs by plant leaves occur widely in the environment, and this should not be neglected when assessing the exposure of humans and other organisms to environmental MPs.
Environmental monitoring, Geochemistry
Phenotypic complexities of rare heterozygous neurexin-1 deletions
Original Paper | Diseases of the nervous system | 2025-04-08 20:00 EDT
Michael B. Fernando, Yu Fan, Yanchun Zhang, Alex Tokolyi, Aleta N. Murphy, Sarah Kammourh, P. J. Michael Deans, Sadaf Ghorbani, Ryan Onatzevitch, Adriana Pero, Christopher Padilla, Sarah E. Williams, Erin K. Flaherty, Iya A. Prytkova, Lei Cao, David A. Knowles, Gang Fang, Paul A. Slesinger, Kristen J. Brennand
Given the large number of genes significantly associated with risk for neuropsychiatric disorders, a critical unanswered question is the extent to which diverse mutations–sometimes affecting the same gene–will require tailored therapeutic strategies. Here we consider this in the context of rare neuropsychiatric disorder-associated copy number variants (2p16.3) resulting in heterozygous deletions in NRXN1, which encodes a presynaptic cell-adhesion protein that serves as a critical synaptic organizer in the brain. Complex patterns of NRXN1 alternative splicing are fundamental to establishing diverse neurocircuitry, vary between the cell types of the brain and are differentially affected by unique (non-recurrent) deletions1. We contrast the cell-type-specific effect of patient-specific mutations in NRXN1 using human-induced pluripotent stem cells, finding that perturbations in NRXN1 splicing result in divergent cell-type-specific synaptic outcomes. Through distinct loss-of-function (LOF) and gain-of-function (GOF) mechanisms, NRXN1+/- deletions cause decreased synaptic activity in glutamatergic neurons, yet increased synaptic activity in GABAergic neurons. Reciprocal isogenic manipulations causally demonstrate that aberrant splicing drives these changes in synaptic activity. For NRXN1 deletions, and perhaps more broadly, precision medicine will require stratifying patients based on whether their gene mutations act through LOF or GOF mechanisms, to achieve individualized restoration of NRXN1 isoform repertoires by increasing wild-type and/or ablating mutant isoforms. Given the increasing number of mutations predicted to engender both LOF and GOF mechanisms in brain disorders, our findings add nuance to future considerations of precision medicine.
Diseases of the nervous system, Synaptic transmission
Human assembloid model of the ascending neural sensory pathway
Original Paper | Neural stem cells | 2025-04-08 20:00 EDT
Ji-il Kim, Kent Imaizumi, Ovidiu Jurjuț, Kevin W. Kelley, Dong Wang, Mayuri Vijay Thete, Zuzana Hudacova, Neal D. Amin, Rebecca J. Levy, Grégory Scherrer, Sergiu P. Pașca
Somatosensory pathways convey crucial information about pain, touch, itch and body part movement from peripheral organs to the central nervous system1,2. Despite substantial needs to understand how these pathways assemble and to develop pain therapeutics, clinical translation remains challenging. This is probably related to species-specific features and the lack of in vitro models of the polysynaptic pathway. Here we established a human ascending somatosensory assembloid (hASA), a four-part assembloid generated from human pluripotent stem cells that integrates somatosensory, spinal, thalamic and cortical organoids to model the spinothalamic pathway. Transcriptomic profiling confirmed the presence of key cell types of this circuit. Rabies tracing and calcium imaging showed that sensory neurons connect to dorsal spinal cord neurons, which further connect to thalamic neurons. Following noxious chemical stimulation, calcium imaging of hASA demonstrated a coordinated response. In addition, extracellular recordings and imaging revealed synchronized activity across the assembloid. Notably, loss of the sodium channel NaV1.7, which causes pain insensitivity, disrupted synchrony across hASA. By contrast, a gain-of-function SCN9A variant associated with extreme pain disorder induced hypersynchrony. These experiments demonstrated the ability to functionally assemble the essential components of the human sensory pathway, which could accelerate our understanding of sensory circuits and facilitate therapeutic development.
Neural stem cells, Neuronal development, Somatosensory system
Perisomatic ultrastructure efficiently classifies cells in mouse cortex
Original Paper | Cellular neuroscience | 2025-04-08 20:00 EDT
Leila Elabbady, Sharmishtaa Seshamani, Shang Mu, Gayathri Mahalingam, Casey M. Schneider-Mizell, Agnes L. Bodor, J. Alexander Bae, Derrick Brittain, JoAnn Buchanan, Daniel J. Bumbarger, Manuel A. Castro, Sven Dorkenwald, Akhilesh Halageri, Zhen Jia, Chris Jordan, Dan Kapner, Nico Kemnitz, Sam Kinn, Kisuk Lee, Kai Li, Ran Lu, Thomas Macrina, Eric Mitchell, Shanka Subhra Mondal, Barak Nehoran, Sergiy Popovych, William Silversmith, Marc Takeno, Russel Torres, Nicholas L. Turner, William Wong, Jingpeng Wu, Wenjing Yin, Szi-chieh Yu, H. Sebastian Seung, R. Clay Reid, Nuno Maçarico da Costa, Forrest Collman
Mammalian neocortex contains a highly diverse set of cell types. These cell types have been mapped systematically using a variety of molecular, electrophysiological and morphological approaches1,2,3,4. Each modality offers new perspectives on the variation of biological processes underlying cell-type specialization. Cellular-scale electron microscopy provides dense ultrastructural examination and an unbiased perspective on the subcellular organization of brain cells, including their synaptic connectivity and nanometre-scale morphology. In data that contain tens of thousands of neurons, most of which have incomplete reconstructions, identifying cell types becomes a clear challenge for analysis5. Here, to address this challenge, we present a systematic survey of the somatic region of all cells in a cubic millimetre of cortex using quantitative features obtained from electron microscopy. This analysis demonstrates that the perisomatic region is sufficient to identify cell types, including types defined primarily on the basis of their connectivity patterns. We then describe how this classification facilitates cell-type-specific connectivity characterization and locating cells with rare connectivity patterns in the dataset.
Cellular neuroscience, Computational neuroscience
Comprehensive interrogation of synthetic lethality in the DNA damage response
Original Paper | DNA damage response | 2025-04-08 20:00 EDT
John Fielden, Sebastian M. Siegner, Danielle N. Gallagher, Markus S. Schröder, Maria Rosaria Dello Stritto, Simon Lam, Lena Kobel, Moritz F. Schlapansky, Stephen P. Jackson, Petr Cejka, Marco Jost, Jacob E. Corn
The DNA damage response (DDR) is a multifaceted network of pathways that preserves genome stability1,2. Unravelling the complementary interplay between these pathways remains a challenge3,4. Here we used CRISPR interference (CRISPRi) screening to comprehensively map the genetic interactions required for survival during normal human cell homeostasis across all core DDR genes. We captured known interactions and discovered myriad new connections that are available online. We defined the molecular mechanism of two of the strongest interactions. First, we found that WDR48 works with USP1 to restrain PCNA degradation in FEN1/LIG1-deficient cells. Second, we found that SMARCAL1 and FANCM directly unwind TA-rich DNA cruciforms, preventing catastrophic chromosome breakage by the ERCC1-ERCC4 complex. Our data yield fundamental insights into genome maintenance, provide a springboard for mechanistic investigations into new connections between DDR factors and pinpoint synthetic vulnerabilities that could be exploited in cancer therapy.
DNA damage response, Double-strand DNA breaks
Seismic imaging of a basaltic Lesser Antilles slab from ancient tectonics
Original Paper | Geophysics | 2025-04-08 20:00 EDT
Xusong Yang, Yujiang Xie, Catherine A. Rychert, Nicholas Harmon, Saskia Goes, Andreas Rietbrock, Lloyd Lynch, Colin G. Macpherson, Jeroen Van Hunen, Jon Davidson, Marjorie Wilson, Robert Allen, Jenny Collier, Jamie J. Wilkinson, Timothy J. Henstock, John-Michael Kendall, Jonathan D. Blundy, Joan Latchman, Richard Robertson
At subduction zones, lithospheric material descends through the upper mantle to the mantle transition zone (MTZ), where it may continue to sink into the lower mantle or stagnate1,2. Several factors may be important in influencing this flow, including chemical heterogeneity3,4,5. However, tight constraints on these mantle flows and the exact factors that affect them have proved challenging. We use P-to-S receiver functions to image the subducting slab and the MTZ beneath the Lesser Antilles subduction zone. We image a singular, superdeep (>700 km) 660-km discontinuity over a 200-km-wide zone within the slab, accompanied by nearby double 660 discontinuity phases (normal and superdeep). Combined geodynamic and waveform modelling shows that this observation cannot be explained by temperature effects in typical mantle compositions but requires a large basalt-rich chemical anomaly, strongest in the location of the singular, deep 660. The inferred basalt signature is near the proposed location of a subducted extinct spreading ridge6,7, where basalt is probably present in greater proportions. Our finding suggests that past tectonic events impart chemical heterogeneity into slabs, and the heterogeneities, in turn, may affect the inherent tendency of the slab to sink.
Geophysics, Seismology
Giant electrocaloric effect in high-polar-entropy perovskite oxides
Original Paper | Energy science and technology | 2025-04-08 20:00 EDT
Feihong Du, Tiannan Yang, Hua Hao, Shangshu Li, Chenhang Xu, Tian Yao, Zhiwu Song, Jiahe Shen, Chenyun Bai, Ruhong Luo, Donglin Han, Qiang Li, Shanyu Zheng, Yingjing Zhang, Yezhan Lin, Zhenhua Ma, Haotian Chen, Chenyu Guo, Jiawang Feng, Shengyi Zhong, Ruilin Mai, Guodong Hou, Haixin Qiu, Meng Xie, Xin Chen, Yakun Yuan, Dong Qian, Dao Xiang, Xuefeng Chen, Zhengqian Fu, Genshui Wang, Hanxing Liu, Jiangping Chen, Guang Meng, Xiangyang Zhu, Long-Qing Chen, Shujun Zhang, Xiaoshi Qian
Materials with a high electrocaloric effect (ECE)1,2 tend to favour a disordered yet easily tunable polar structure. Perovskite ferroelectrics3 stand out as ideal candidates owing to their high dielectric responses and reasonable thermal conductivity. The introduction of multielement atomic distortions induces a high-polar-entropy state4 that notably increases the ECE by effectively overcoming the constraints imposed by highly ordered, polar-correlated perovskite structures. Here we developed a lead-free relaxor ferroelectric with strong polar disorder through targeted multielement substitution at both the A and B sites of the perovskite, effectively distorting the lattice structure and inducing a variety of nanoscale polar configurations, polymorphic polar variants and non-polar regions. A combination of these multielement-induced features led to an increased density of interfaces, significantly enhancing the polar entropy. Remarkably, a high ECE for an entropy change of about 15 J kg-1 K-1 under a 10 MV m-1 field is observed for the material across a broad temperature range exceeding 60 °C. The formation of ultrafine, dispersed, multiphase lattice configurations leads to high-polar-entropy ferroelectric oxides with a high ECE and a long lifetime of over 1 million cycles that are suitable for manufacturing multilayer ceramic capacitors for practical electrocaloric refrigeration applications.
Energy science and technology, Ferroelectrics and multiferroics
A non-contact wearable device for monitoring epidermal molecular flux
Original Paper | Biomedical engineering | 2025-04-08 20:00 EDT
Jaeho Shin, Joseph Woojin Song, Matthew Thomas Flavin, Seunghee Cho, Shupeng Li, Ansen Tan, Kyung Rok Pyun, Aaron G Huang, Huifeng Wang, Seongmin Jeong, Kenneth E. Madsen, Jacob Trueb, Mirae Kim, Katelynn Nguyen, Angela Yang, Yaching Hsu, Winnie Sung, Jiwon Lee, Sooyeol Phyo, Ji-Hoon Kim, Anthony Banks, Jan-Kai Chang, Amy S. Paller, Yonggang Huang, Guillermo A. Ameer, John A. Rogers
Existing wearable technologies rely on physical coupling to the body to establish optical1,2, fluidic3,4, thermal5,6 and/or mechanical7,8 measurement interfaces. Here we present a class of wearable device platforms that instead relies on physical decoupling to define an enclosed chamber immediately adjacent to the skin surface. Streams of vapourized molecular substances that pass out of or into the skin alter the properties of the microclimate defined in this chamber in ways that can be precisely quantified using an integrated collection of wireless sensors. A programmable, bistable valve dynamically controls access to the surrounding environment, thereby creating a transient response that can be quantitatively related to the inward and outward fluxes of the targeted species by analysing the time-dependent readings from the sensors. The systems reported here offer unique capabilities in measuring the flux of water vapour, volatile organic compounds and carbon dioxide from various locations on the body, each with distinct relevance to clinical care and/or exposure to hazardous vapours. Studies of healing processes associated with dermal wounds in models of healthy and diabetic mice and of responses in models using infected wounds reveal characteristic flux variations that provide important insights, particularly in scenarios in which the non-contact operation of the devices avoids potential damage to fragile tissues.
Biomedical engineering, Diagnosis
Reprogramming site-specific retrotransposon activity to new DNA sites
Original Paper | Biotechnology | 2025-04-08 20:00 EDT
Christopher W. Fell, Lukas Villiger, Justin Lim, Masahiro Hiraizumi, Dario Tagliaferri, Matthew T. N. Yarnall, Anderson Lee, Kaiyi Jiang, Alisan Kayabolen, Rohan N. Krajeski, Cian Schmitt-Ulms, Harsh Ramani, Sarah M. Yousef, Nathaniel Roberts, Christopher A. Vakulskas, Hiroshi Nishimasu, Omar O. Abudayyeh, Jonathan S. Gootenberg
Retroelements have a critical role in shaping eukaryotic genomes. For instance, site-specific non-long terminal repeat retrotransposons have spread widely through preferential integration into repetitive genomic sequences, such as microsatellite regions and ribosomal DNA genes1,2,3,4,5,6. Despite the widespread occurrence of these systems, their targeting constraints remain unclear. Here we use a computational pipeline to discover multiple new site-specific retrotransposon families, profile members both biochemically and in mammalian cells, find previously undescribed insertion preferences and chart potential evolutionary paths for retrotransposon retargeting. We identify R2Tg, an R2 retrotransposon from the zebra finch, Taeniopygia guttata, as an orthologue that can be retargeted by payload engineering for target cleavage, reverse transcription and scarless insertion of heterologous payloads at new genomic sites. We enhance this activity by fusing R2Tg to CRISPR-Cas9 nickases for efficient insertion at new genomic sites. Through further screening of R2 orthologues, we select an orthologue, R2Tocc, with natural reprogrammability and minimal insertion at its natural 28S site, to engineer SpCas9H840A-R2Tocc, a system we name site-specific target-primed insertion through targeted CRISPR homing of retroelements (STITCHR). STITCHR enables the scarless, efficient installation of edits, ranging from a single base to 12.7 kilobases, gene replacement and use of in vitro transcribed or synthetic RNA templates. Inspired by the prevalence of nLTR retrotransposons across eukaryotic genomes, we anticipate that STITCHR will serve as a platform for scarless programmable integration in dividing and non-dividing cells, with both research and therapeutic applications.
Biotechnology, Genetic engineering, Transposition
Hunter-gatherer sea voyages extended to remotest Mediterranean islands
Original Paper | Archaeology | 2025-04-08 20:00 EDT
Eleanor M. L. Scerri, James Blinkhorn, Huw S. Groucutt, Mathew Stewart, Ian Candy, Ethel Allué, Aitor Burguet-Coca, Andrés Currás, W. Christopher Carleton, Susanne Lindauer, Robert Spengler, Kseniia Boxleitner, Gillian Asciak, Margherita Colucci, Ritienne Gauci, Amy Hatton, Johanna Kutowsky, Andreas Maier, Mario Mata-González, Nicolette Mifsud, Khady Niang, Patrick Roberts, Joshua de Giorgio, Rochelle Xerri, Nicholas C. Vella
The Maltese archipelago is a small island chain that is among the most remote in the Mediterranean. Humans were not thought to have reached and inhabited such small and isolated islands until the regional shift to Neolithic lifeways, around 7.5 thousand years ago (ka)1. In the standard view, the limited resources and ecological vulnerabilities of small islands, coupled with the technological challenges of long-distance seafaring, meant that hunter-gatherers were either unable or unwilling to make these journeys2,3,4. Here we describe chronological, archaeological, faunal and botanical data that support the presence of Holocene hunter-gatherers on the Maltese islands. At this time, Malta’s geographical configuration and sea levels approximated those of the present day, necessitating seafaring distances of around 100 km from Sicily, the closest landmass. Occupations began at around 8.5 ka and are likely to have lasted until around 7.5 ka. These hunter-gatherers exploited land animals, but were also able to take advantage of marine resources and avifauna, helping to sustain these groups on a small island. Our discoveries document the longest yet-known hunter-gatherer sea crossings in the Mediterranean, raising the possibility of unknown, precocious connections across the wider region.
Archaeology, Palaeoecology
NEURD offers automated proofreading and feature extraction for connectomics
Original Paper | Data processing | 2025-04-08 20:00 EDT
Brendan Celii, Stelios Papadopoulos, Zhuokun Ding, Paul G. Fahey, Eric Wang, Christos Papadopoulos, Alexander B. Kunin, Saumil Patel, J. Alexander Bae, Agnes L. Bodor, Derrick Brittain, JoAnn Buchanan, Daniel J. Bumbarger, Manuel A. Castro, Erick Cobos, Sven Dorkenwald, Leila Elabbady, Akhilesh Halageri, Zhen Jia, Chris Jordan, Dan Kapner, Nico Kemnitz, Sam Kinn, Kisuk Lee, Kai Li, Ran Lu, Thomas Macrina, Gayathri Mahalingam, Eric Mitchell, Shanka Subhra Mondal, Shang Mu, Barak Nehoran, Sergiy Popovych, Casey M. Schneider-Mizell, William Silversmith, Marc Takeno, Russel Torres, Nicholas L. Turner, William Wong, Jingpeng Wu, Szi-chieh Yu, Wenjing Yin, Daniel Xenes, Lindsey M. Kitchell, Patricia K. Rivlin, Victoria A. Rose, Caitlyn A. Bishop, Brock Wester, Emmanouil Froudarakis, Edgar Y. Walker, Fabian Sinz, H. Sebastian Seung, Forrest Collman, Nuno Maçarico da Costa, R. Clay Reid, Xaq Pitkow, Andreas S. Tolias, Jacob Reimer
We are in the era of millimetre-scale electron microscopy volumes collected at nanometre resolution1,2. Dense reconstruction of cellular compartments in these electron microscopy volumes has been enabled by recent advances in machine learning3,4,5,6. Automated segmentation methods produce exceptionally accurate reconstructions of cells, but post hoc proofreading is still required to generate large connectomes that are free of merge and split errors. The elaborate 3D meshes of neurons in these volumes contain detailed morphological information at multiple scales, from the diameter, shape and branching patterns of axons and dendrites, down to the fine-scale structure of dendritic spines. However, extracting these features can require substantial effort to piece together existing tools into custom workflows. Here, building on existing open source software for mesh manipulation, we present Neural Decomposition (NEURD), a software package that decomposes meshed neurons into compact and extensively annotated graph representations. With these feature-rich graphs, we automate a variety of tasks such as state-of-the-art automated proofreading of merge errors, cell classification, spine detection, axonal-dendritic proximities and other annotations. These features enable many downstream analyses of neural morphology and connectivity, making these massive and complex datasets more accessible to neuroscience researchers.
Data processing, Machine learning, Neural circuits, Software
Complete sequencing of ape genomes
Original Paper | Centromeres | 2025-04-08 20:00 EDT
DongAhn Yoo, Arang Rhie, Prajna Hebbar, Francesca Antonacci, Glennis A. Logsdon, Steven J. Solar, Dmitry Antipov, Brandon D. Pickett, Yana Safonova, Francesco Montinaro, Yanting Luo, Joanna Malukiewicz, Jessica M. Storer, Jiadong Lin, Abigail N. Sequeira, Riley J. Mangan, Glenn Hickey, Graciela Monfort Anez, Parithi Balachandran, Anton Bankevich, Christine R. Beck, Arjun Biddanda, Matthew Borchers, Gerard G. Bouffard, Emry Brannan, Shelise Y. Brooks, Lucia Carbone, Laura Carrel, Agnes P. Chan, Juyun Crawford, Mark Diekhans, Eric Engelbrecht, Cedric Feschotte, Giulio Formenti, Gage H. Garcia, Luciana de Gennaro, David Gilbert, Richard E. Green, Andrea Guarracino, Ishaan Gupta, Diana Haddad, Junmin Han, Robert S. Harris, Gabrielle A. Hartley, William T. Harvey, Michael Hiller, Kendra Hoekzema, Marlys L. Houck, Hyeonsoo Jeong, Kaivan Kamali, Manolis Kellis, Bryce Kille, Chul Lee, Youngho Lee, William Lees, Alexandra P. Lewis, Qiuhui Li, Mark Loftus, Yong Hwee Eddie Loh, Hailey Loucks, Jian Ma, Yafei Mao, Juan F. I. Martinez, Patrick Masterson, Rajiv C. McCoy, Barbara McGrath, Sean McKinney, Britta S. Meyer, Karen H. Miga, Saswat K. Mohanty, Katherine M. Munson, Karol Pal, Matt Pennell, Pavel A. Pevzner, David Porubsky, Tamara Potapova, Francisca R. Ringeling, Joana L. Rocha, Oliver A. Ryder, Samuel Sacco, Swati Saha, Takayo Sasaki, Michael C. Schatz, Nicholas J. Schork, Cole Shanks, Linnéa Smeds, Dongmin R. Son, Cynthia Steiner, Alexander P. Sweeten, Michael G. Tassia, Françoise Thibaud-Nissen, Edmundo Torres-González, Mihir Trivedi, Wenjie Wei, Julie Wertz, Muyu Yang, Panpan Zhang, Shilong Zhang, Yang Zhang, Zhenmiao Zhang, Sarah A. Zhao, Yixin Zhu, Erich D. Jarvis, Jennifer L. Gerton, Iker Rivas-González, Benedict Paten, Zachary A. Szpiech, Christian D. Huber, Tobias L. Lenz, Miriam K. Konkel, Soojin V. Yi, Stefan Canzar, Corey T. Watson, Peter H. Sudmant, Erin Molloy, Erik Garrison, Craig B. Lowe, Mario Ventura, Rachel J. O’Neill, Sergey Koren, Kateryna D. Makova, Adam M. Phillippy, Evan E. Eichler
The most dynamic and repetitive regions of great ape genomes have traditionally been excluded from comparative studies1,2,3. Consequently, our understanding of the evolution of our species is incomplete. Here we present haplotype-resolved reference genomes and comparative analyses of six ape species: chimpanzee, bonobo, gorilla, Bornean orangutan, Sumatran orangutan and siamang. We achieve chromosome-level contiguity with substantial sequence accuracy (<1 error in 2.7 megabases) and completely sequence 215 gapless chromosomes telomere-to-telomere. We resolve challenging regions, such as the major histocompatibility complex and immunoglobulin loci, to provide in-depth evolutionary insights. Comparative analyses enabled investigations of the evolution and diversity of regions previously uncharacterized or incompletely studied without bias from mapping to the human reference genome. Such regions include newly minted gene families in lineage-specific segmental duplications, centromeric DNA, acrocentric chromosomes and subterminal heterochromatin. This resource serves as a comprehensive baseline for future evolutionary studies of humans and our closest living ape relatives.
Centromeres, Comparative genomics, Evolutionary genetics, Genome evolution, Genome informatics
DNA-guided transcription factor interactions extend human gene regulatory code
Original Paper | High-throughput screening | 2025-04-08 20:00 EDT
Zhiyuan Xie, Ilya Sokolov, Maria Osmala, Xue Yue, Grace Bower, J. Patrick Pett, Yinan Chen, Kai Wang, Ayse Derya Cavga, Alexander Popov, Sarah A. Teichmann, Ekaterina Morgunova, Evgeny Z. Kvon, Yimeng Yin, Jussi Taipale
In the same way that the mRNA-binding specificities of transfer RNAs define the genetic code, the DNA-binding specificities of transcription factors (TFs) form the molecular basis of the gene regulatory code1,2. The human gene regulatory code is much more complex than the genetic code, in particular because there are more than 1,600 TFs that commonly interact with each other. TF-TF interactions are required for specifying cell fate and executing cell-type-specific transcriptional programs. Despite this, the landscape of interactions between DNA-bound TFs is poorly defined. Here we map the biochemical interactions between DNA-bound TFs using CAP-SELEX, a method that can simultaneously identify individual TF binding preferences, TF-TF interactions and the DNA sequences that are bound by the interacting complexes. A screen of more than 58,000 TF-TF pairs identified 2,198 interacting TF pairs, 1,329 of which preferentially bound to their motifs arranged in a distinct spacing and/or orientation. We also discovered 1,131 TF-TF composite motifs that were markedly different from the motifs of the individual TFs. In total, we estimate that the screen identified between 18% and 47% of all human TF-TF motifs. The novel composite motifs we found were enriched in cell-type-specific elements, active in vivo and more likely to be formed between developmentally co-expressed TFs. Furthermore, TFs that define embryonic axes commonly interacted with different TFs and bound to distinct motifs, explaining how TFs with a similar specificity can define distinct cell types along developmental axes.
High-throughput screening, Systems analysis, Transcriptional regulatory elements
Goal-specific hippocampal inhibition gates learning
Original Paper | Hippocampus | 2025-04-08 20:00 EDT
Nuri Jeong, Xiao Zheng, Abigail L. Paulson, Stephanie M. Prince, Victor P. Nguyen, Sherina R. Thomas, Caroline E. Gilpin, Matthew C. Goodson, Annabelle C. Singer
Goal-directed navigation in a new environment requires quickly identifying and exploiting important locations. Identifying new goal locations depends on neural computations that rapidly represent locations and connect location information to key outcomes such as food1. However, the mechanisms to trigger these computations at behaviourally relevant locations are not well understood. Here we show that parvalbumin (PV)-positive interneurons in the mouse hippocampal CA3 have a causal role in identifying and exploiting new food locations such that decreases in inhibitory activity around goals enable reactivation to bind goal locations to food outcomes. PV interneurons in the CA3 substantially reduce firing on approach to and at goal locations while food-deprived mice learn to find food. These inhibitory decreases anticipate reward locations as the mice learn and are more prominent on correct trials. Sparse optogenetic stimulation to prevent goal-related decreases in PV interneuron firing impaired learning of goal locations. Disrupting goal-related decreases in PV interneuron activity impaired the reactivation of new goal locations after receipt of food, a process that associates previous locations to food outcomes such that the mice know where to seek food later. These results reveal that goal-selective and goal-predictive decreases in inhibitory activity enable learning, representations and outcome associations of crucial locations.
Hippocampus, Inhibition, Neural circuits, Reward, Spatial memory
Transforming ceria into 2D clusters enhances catalytic activity
Original Paper | Catalyst synthesis | 2025-04-08 20:00 EDT
Konstantin Khivantsev, Hien Pham, Mark H. Engelhard, Hristiyan A. Aleksandrov, Libor Kovarik, Mark Bowden, Xiaohong Shari Li, Jinshu Tian, Iskra Z. Koleva, Inhak Song, Wenda Hu, Xinyi Wei, Yipeng Sun, Pascaline Tran, Trent R. Graham, Dong Jiang, David P. Dean, Christian J. Breckner, Jeffrey T. Miller, Georgi N. Vayssilov, János Szanyi, Abhaya Datye, Yong Wang
Ceria nanoparticles supported on alumina are widely used in various catalytic reactions, particularly in conjunction with platinum group metals (PGMs)1,2,3,4,5,6,7,8,9. Here we found that treating these catalysts at temperatures between 750 and about 1,000 °C in the presence of CO and NO in steam (reactive treatment under reducing atmosphere) leads to the dispersion of ceria nanoparticles into high-density 2D (roughly one atomic layer thin) CexOy domains, as confirmed by microscopy, X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), infrared spectroscopy and density functional theory (DFT) calculations. These domains, which densely cover the alumina, exhibit substantially enhanced oxygen mobility and storage capacity, facilitating easier extraction of oxygen and the formation of Ce3+ sites and oxygen vacancies. As a result, these catalysts–whether with or without PGMs, such as Rh and Pt–show improved activity for several industrially important catalytic reactions, including NO and N2O reduction, as well as CO and NO oxidation, even after exposure to harsh ageing conditions. This study shows a catalyst architecture with superior redox properties under conditions that typically cause sintering, offering a pathway to more efficient metal-ceria catalysts for enhanced general catalysis.
Catalyst synthesis, Heterogeneous catalysis
Inhibitory specificity from a connectomic census of mouse visual cortex
Original Paper | Computational neuroscience | 2025-04-08 20:00 EDT
Casey M. Schneider-Mizell, Agnes L. Bodor, Derrick Brittain, JoAnn Buchanan, Daniel J. Bumbarger, Leila Elabbady, Clare Gamlin, Daniel Kapner, Sam Kinn, Gayathri Mahalingam, Sharmishtaa Seshamani, Shelby Suckow, Marc Takeno, Russel Torres, Wenjing Yin, Sven Dorkenwald, J. Alexander Bae, Manuel A. Castro, Akhilesh Halageri, Zhen Jia, Chris Jordan, Nico Kemnitz, Kisuk Lee, Kai Li, Ran Lu, Thomas Macrina, Eric Mitchell, Shanka Subhra Mondal, Shang Mu, Barak Nehoran, Sergiy Popovych, William Silversmith, Nicholas L. Turner, William Wong, Jingpeng Wu, Jacob Reimer, Andreas S. Tolias, H. Sebastian Seung, R. Clay Reid, Forrest Collman, Nuno Maçarico da Costa
Mammalian cortex features a vast diversity of neuronal cell types, each with characteristic anatomical, molecular and functional properties1. Synaptic connectivity shapes how each cell type participates in the cortical circuit, but mapping connectivity rules at the resolution of distinct cell types remains difficult. Here we used millimetre-scale volumetric electron microscopy2 to investigate the connectivity of all inhibitory neurons across a densely segmented neuronal population of 1,352 cells spanning all layers of mouse visual cortex, producing a wiring diagram of inhibition with more than 70,000 synapses. Inspired by classical neuroanatomy, we classified inhibitory neurons based on targeting of dendritic compartments and developed an excitatory neuron classification based on dendritic reconstructions with whole-cell maps of synaptic input. Single-cell connectivity showed a class of disinhibitory specialist that targets basket cells. Analysis of inhibitory connectivity onto excitatory neurons found widespread specificity, with many interneurons exhibiting differential targeting of spatially intermingled subpopulations. Inhibitory targeting was organized into ‘motif groups’, diverse sets of cells that collectively target both perisomatic and dendritic compartments of the same excitatory targets. Collectively, our analysis identified new organizing principles for cortical inhibition and will serve as a foundation for linking contemporary multimodal neuronal atlases with the cortical wiring diagram.
Computational neuroscience, Neural circuits, Visual system
Water abundance in the lunar farside mantle
Original Paper | Geochemistry | 2025-04-08 20:00 EDT
Huicun He, Linxi Li, Sen Hu, Yubing Gao, Liang Gao, Zhan Zhou, Mengfan Qiu, Disheng Zhou, Huanxin Liu, Ruiying Li, Jialong Hao, Hejiu Hui, Yangting Lin
The water contents of the lunar interior record important clues for understanding the formation and subsequent thermochemical evolution of the Moon1. The Chang’e-6 (CE6) mission returned samples from the South Pole-Aitken impact basin of the lunar farside2,3,4, providing an opportunity to study the water contents of the farside mantle. Here we report the water abundances and hydrogen isotope compositions of apatite and melt inclusions from CE6 mare basalt, derived from partial melting of the lunar mantle. The parent magma of CE6 mare basalt is estimated to have a water abundance of 15-168 μg g-1 with a δD value of -123 ± 167‰. Our estimate of water abundance of 1-1.5 μg g-1 for the mantle source indicates that the farside mantle is potentially drier than its nearside counterpart. This contrast thus suggests that the distribution of water in the interior of the Moon may exhibit a hemispheric dichotomy similar to numerous surface features5. The new estimate for the lunar farside mantle represents a landmark for estimating the water abundance of the bulk silicate Moon, providing critical constraints on the giant impact origin hypothesis6,7,8 and the subsequent evolution of the Moon for which the role of water is central1,9.
Geochemistry, Planetary science
Small molecules restore mutant mitochondrial DNA polymerase activity
Original Paper | Cryoelectron microscopy | 2025-04-08 20:00 EDT
Sebastian Valenzuela, Xuefeng Zhu, Bertil Macao, Mattias Stamgren, Carol Geukens, Paul S. Charifson, Gunther Kern, Emily Hoberg, Louise Jenninger, Anja V. Gruszczyk, Seoeun Lee, Katarina A. S. Johansson, Javier Miralles Fusté, Yonghong Shi, S. Jordan Kerns, Laleh Arabanian, Gabriel Martinez Botella, Sofie Ekström, Jeremy Green, Andrew M. Griffin, Carlos Pardo-Hernández, Thomas A. Keating, Barbara Küppers-Munther, Nils-Göran Larsson, Cindy Phan, Viktor Posse, Juli E. Jones, Xie Xie, Simon Giroux, Claes M. Gustafsson, Maria Falkenberg
Mammalian mitochondrial DNA (mtDNA) is replicated by DNA polymerase γ (POLγ), a heterotrimeric complex consisting of a catalytic POLγA subunit and two accessory POLγB subunits1. More than 300 mutations in POLG, the gene encoding the catalytic subunit, have been linked to severe, progressive conditions with high rates of morbidity and mortality, for which no treatment exists2. Here we report on the discovery and characterization of PZL-A, a first-in-class small-molecule activator of mtDNA synthesis that is capable of restoring function to the most common mutant variants of POLγ. PZL-A binds to an allosteric site at the interface between the catalytic POLγA subunit and the proximal POLγB subunit, a region that is unaffected by nearly all disease-causing mutations. The compound restores wild-type-like activity to mutant forms of POLγ in vitro and activates mtDNA synthesis in cells from paediatric patients with lethal POLG disease, thereby enhancing biogenesis of the oxidative phosphorylation machinery and cellular respiration. Our work demonstrates that a small molecule can restore function to mutant DNA polymerases, offering a promising avenue for treating POLG disorders and other severe conditions linked to depletion of mtDNA.
Cryoelectron microscopy, Enzyme mechanisms, Metabolic disorders, Structure-based drug design
Translational genomics of osteoarthritis in 1,962,069 individuals
Original Paper | Functional genomics | 2025-04-08 20:00 EDT
Konstantinos Hatzikotoulas, Lorraine Southam, Lilja Stefansdottir, Cindy G. Boer, Merry-Lynn McDonald, J. Patrick Pett, Young-Chan Park, Margo Tuerlings, Rick Mulders, Andrei Barysenka, Ana Luiza Arruda, Vinicius Tragante, Alison Rocco, Norbert Bittner, Shibo Chen, Susanne Horn, Vinodh Srinivasasainagendra, Ken To, Georgia Katsoula, Peter Kreitmaier, Amabel M. M. Tenghe, Arthur Gilly, Liubov Arbeeva, Lane G. Chen, Agathe M. de Pins, Daniel Dochtermann, Cecilie Henkel, Jonas Höijer, Shuji Ito, Penelope A. Lind, Bitota Lukusa-Sawalena, Aye Ko Ko Minn, Marina Mola-Caminal, Akira Narita, Chelsea Nguyen, Ene Reimann, Micah D. Silberstein, Anne-Heidi Skogholt, Hemant K. Tiwari, Michelle S. Yau, Ming Yue, Wei Zhao, Jin J. Zhou, George Alexiadis, Karina Banasik, Søren Brunak, Archie Campbell, Jackson T. S. Cheung, Joseph Dowsett, Tariq Faquih, Jessica D. Faul, Lijiang Fei, Anne Marie Fenstad, Takamitsu Funayama, Maiken E. Gabrielsen, Chinatsu Gocho, Kirill Gromov, Thomas Hansen, Georgi Hudjashov, Thorvaldur Ingvarsson, Jessica S. Johnson, Helgi Jonsson, Saori Kakehi, Juha Karjalainen, Elisa Kasbohm, Susanna Lemmelä, Kuang Lin, Xiaoxi Liu, Marieke Loef, Massimo Mangino, Daniel McCartney, Iona Y. Millwood, Joshua Richman, Mary B. Roberts, Kathleen A. Ryan, Dino Samartzis, Manu Shivakumar, Søren T. Skou, Sachiyo Sugimoto, Ken Suzuki, Hiroshi Takuwa, Maris Teder-Laving, Laurent Thomas, Kohei Tomizuka, Constance Turman, Stefan Weiss, Tian T. Wu, Eleni Zengini, Yanfei Zhang, George Babis, David A. van Heel, Bendik Winsvold, Maiken Gabrielsen, Manuel Allen Revez Ferreira, George Babis, Aris Baras, Tyler Barker, David J. Carey, Kathryn S. E. Cheah, Zhengming Chen, Jason Pui-Yin Cheung, Mark Daly, Renée de Mutsert, Charles B. Eaton, Christian Erikstrup, Ove Nord Furnes, Yvonne M. Golightly, Daniel F. Gudbjartsson, Nils P. Hailer, Caroline Hayward, Marc C. Hochberg, Georg Homuth, Laura M. Huckins, Kristian Hveem, Shiro Ikegawa, Muneaki Ishijima, Minoru Isomura, Marcus Jones, Jae H. Kang, Sharon L. R. Kardia, Margreet Kloppenburg, Peter Kraft, Nobuyuki Kumahashi, Suguru Kuwata, Ming Ta Michael Lee, Phil H. Lee, Robin Lerner, Liming Li, Steve A. Lietman, Luca Lotta, Michelle K. Lupton, Reedik Mägi, Nicholas G. Martin, Timothy E. McAlindon, Sarah E. Medland, Karl Michaëlsson, Braxton D. Mitchell, Dennis O. Mook-Kanamori, Andrew P. Morris, Toru Nabika, Fuji Nagami, Amanda E. Nelson, Sisse Rye Ostrowski, Aarno Palotie, Ole Birger Pedersen, Frits R. Rosendaal, Mika Sakurai-Yageta, Carsten Oliver Schmidt, Pak Chung Sham, Jasvinder A. Singh, Diane T. Smelser, Jennifer A. Smith, You-qiang Song, Erik Sørensen, Gen Tamiya, Yoshifumi Tamura, Chikashi Terao, Gudmar Thorleifsson, Anders Troelsen, Aspasia Tsezou, Yuji Uchio, A. G. Uitterlinden, Henrik Ullum, Ana M. Valdes, David A. van Heel, Robin G. Walters, David R. Weir, J. Mark Wilkinson, Bendik S. Winsvold, Masayuki Yamamoto, John-Anker Zwart, Kari Stefansson, Ingrid Meulenbelt, Sarah A. Teichmann, Joyce B. J. van Meurs, Unnur Styrkarsdottir, Eleftheria Zeggini
Osteoarthritis is the third most rapidly growing health condition associated with disability, after dementia and diabetes1. By 2050, the total number of patients with osteoarthritis is estimated to reach 1 billion worldwide2. As no disease-modifying treatments exist for osteoarthritis, a better understanding of disease aetiopathology is urgently needed. Here we perform a genome-wide association study meta-analyses across up to 489,975 cases and 1,472,094 controls, establishing 962 independent associations, 513 of which have not been previously reported. Using single-cell multiomics data, we identify signal enrichment in embryonic skeletal development pathways. We integrate orthogonal lines of evidence, including transcriptome, proteome and epigenome profiles of primary joint tissues, and implicate 700 effector genes. Within these, we find rare coding-variant burden associations with effect sizes that are consistently higher than common frequency variant associations. We highlight eight biological processes in which we find convergent involvement of multiple effector genes, including the circadian clock, glial-cell-related processes and pathways with an established role in osteoarthritis (TGFβ, FGF, WNT, BMP and retinoic acid signalling, and extracellular matrix organization). We find that 10% of the effector genes express a protein that is the target of approved drugs, offering repurposing opportunities, which can accelerate translation.
Functional genomics, Genome-wide association studies, Genomics, Osteoarthritis, Translational research
Functional connectomics spanning multiple areas of mouse visual cortex
Original Paper | Neural circuits | 2025-04-08 20:00 EDT
J. Alexander Bae, Mahaly Baptiste, Maya R. Baptiste, Caitlyn A. Bishop, Agnes L. Bodor, Derrick Brittain, Victoria Brooks, JoAnn Buchanan, Daniel J. Bumbarger, Manuel A. Castro, Brendan Celii, Erick Cobos, Forrest Collman, Nuno Maçarico da Costa, Bethanny Danskin, Sven Dorkenwald, Leila Elabbady, Paul G. Fahey, Tim Fliss, Emmanouil Froudarakis, Jay Gager, Clare Gamlin, William Gray-Roncal, Akhilesh Halageri, James Hebditch, Zhen Jia, Emily Joyce, Justin Ellis-Joyce, Chris Jordan, Daniel Kapner, Nico Kemnitz, Sam Kinn, Lindsey M. Kitchell, Selden Koolman, Kai Kuehner, Kisuk Lee, Kai Li, Ran Lu, Thomas Macrina, Gayathri Mahalingam, Jordan Matelsky, Sarah McReynolds, Elanine Miranda, Eric Mitchell, Shanka Subhra Mondal, Merlin Moore, Shang Mu, Taliah Muhammad, Barak Nehoran, Erika Neace, Oluwaseun Ogedengbe, Christos Papadopoulos, Stelios Papadopoulos, Saumil Patel, Guadalupe Jovita Yasmin Perez Vega, Xaq Pitkow, Sergiy Popovych, Anthony Ramos, R. Clay Reid, Jacob Reimer, Patricia K. Rivlin, Victoria Rose, Zachary M. Sauter, Casey M. Schneider-Mizell, H. Sebastian Seung, Ben Silverman, William Silversmith, Amy Sterling, Fabian H. Sinz, Cameron L. Smith, Rachael Swanstrom, Shelby Suckow, Marc Takeno, Zheng H. Tan, Andreas S. Tolias, Russel Torres, Nicholas L. Turner, Edgar Y. Walker, Tianyu Wang, Adrian Wanner, Brock A. Wester, Grace Williams, Sarah Williams, Kyle Willie, Ryan Willie, William Wong, Jingpeng Wu, Chris Xu, Runzhe Yang, Dimitri Yatsenko, Fei Ye, Wenjing Yin, Rob Young, Szi-chieh Yu, Daniel Xenes, Chi Zhang
Understanding the brain requires understanding neurons’ functional responses to the circuit architecture shaping them. Here we introduce the MICrONS functional connectomics dataset with dense calcium imaging of around 75,000 neurons in primary visual cortex (VISp) and higher visual areas (VISrl, VISal and VISlm) in an awake mouse that is viewing natural and synthetic stimuli. These data are co-registered with an electron microscopy reconstruction containing more than 200,000 cells and 0.5 billion synapses. Proofreading of a subset of neurons yielded reconstructions that include complete dendritic trees as well the local and inter-areal axonal projections that map up to thousands of cell-to-cell connections per neuron. Released as an open-access resource, this dataset includes the tools for data retrieval and analysis1,2. Accompanying studies describe its use for comprehensive characterization of cell types3,4,5,6, a synaptic level connectivity diagram of a cortical column4, and uncovering cell-type-specific inhibitory connectivity that can be linked to gene expression data4,7. Functionally, we identify new computational principles of how information is integrated across visual space8, characterize novel types of neuronal invariances9 and bring structure and function together to uncover a general principle for connectivity between excitatory neurons within and across areas10,11.
Neural circuits, Striate cortex
A Jurassic acanthocephalan illuminates the origin of thorny-headed worms
Original Paper | Evolutionary ecology | 2025-04-08 20:00 EDT
Cihang Luo, Luke A. Parry, Brendon E. Boudinot, Shengyu Wang, Edmund A. Jarzembowski, Haichun Zhang, Bo Wang
Acanthocephala (thorny-headed worms), characterized by the presence of an eversible proboscis with hooks, are a diverse endoparasitic group that infect a wide range of vertebrates and invertebrates1. Although long regarded as a separate phylum, they have several putative sister taxa based on morphological features, including Platyhelminthes (flatworms)2, Priapulida (penis worms)3 and Rotifera (wheel animals)4. Molecular phylogenies have instead recovered them within rotifers5,6,7,8,9,10, suggesting acanthocephalans are derived from free-living worms with a jaw apparatus (Gnathifera). Their only fossil record is Late Cretaceous eggs11, contributing limited palaeontological information to deciphering their early evolution. Here we describe an acanthocephalan body fossil, Juracanthocephalus daohugouensis gen. et. sp. nov., from the Middle Jurassic Daohugou biota of China. Juracanthocephalus shows unambiguous acanthocephalan characteristics, for example a hooked proboscis, a bursa, as well as a jaw apparatus with discrete elements that is typical of other gnathiferans. Juracanthocephalus shares features with Seisonidea (an epizoic member of Rotifera) and Acanthocephala, bridging the evolutionary gap between jawed rotifers and the obligate parasitic, jawless acanthocephalans. Our results reveal previously unrecognized ecological and morphological diversity in ancient Acanthocephala and highlight the significance of transitional fossils, revealing the origins of this highly enigmatic group of living organisms.
Evolutionary ecology, Palaeontology
Evidence of star cluster migration and merger in dwarf galaxies
Original Paper | Computational astrophysics | 2025-04-08 20:00 EDT
Mélina Poulain, Rory Smith, Pierre-Alain Duc, Francine R. Marleau, Rebecca Habas, Patrick R. Durrell, Jérémy Fensch, Sungsoon Lim, Oliver Müller, Sanjaya Paudel, Rubén Sánchez-Janssen
Nuclear star clusters (NSCs) are the densest stellar systems in the Universe. These clusters can be found at the centre of all galaxy types but tend to favour galaxies of intermediate stellar mass around 109M⊙ (refs. 1,2). At present, two main processes are under debate to explain their formation: in situ star formation from gas infall3 and migration and merging of globular clusters (GCs) caused by dynamical friction4. Studies5,6,7,8,9 of NSC stellar populations suggest that the former predominates in massive galaxies, whereas the latter prevails in dwarf galaxies, and both contribute equally at intermediate mass. However, until now, no ongoing merger of GCs has been observed to confirm this scenario. Here we report the serendipitous discovery of five dwarf galaxies with complex nuclear regions, characterized by multiple nuclei and tidal tails, using high-resolution images from the Hubble Space Telescope. These structures have been reproduced in complementary N-body simulations, supporting the interpretation that they result from migrating and merging of star clusters. The small detection rate and short simulated timescales (below 100 Myr) of this process may explain why this has not been observed previously. This study highlights the need for large surveys with high resolution to fully map the migration scenario steps.
Computational astrophysics, Galaxies and clusters
Stress dynamically modulates neuronal autophagy to gate depression onset
Original Paper | Depression | 2025-04-08 20:00 EDT
Liang Yang, Chen Guo, Zhiwei Zheng, Yiyan Dong, Qifeng Xie, Zijian Lv, Min Li, Yangyang Lu, Xiaonan Guo, Rongshan Deng, Yiqin Liu, Yirong Feng, Ruiqi Mu, Xuliang Zhang, Huan Ma, Zhong Chen, Zhijun Zhang, Zhaoqi Dong, Wei Yang, Xiangnan Zhang, Yihui Cui
Chronic stress remodels brain homeostasis, in which persistent change leads to depressive disorders1. As a key modulator of brain homeostasis2, it remains elusive whether and how brain autophagy is engaged in stress dynamics. Here we discover that acute stress activates, whereas chronic stress suppresses, autophagy mainly in the lateral habenula (LHb). Systemic administration of distinct antidepressant drugs similarly restores autophagy function in the LHb, suggesting LHb autophagy as a common antidepressant target. Genetic ablation of LHb neuronal autophagy promotes stress susceptibility, whereas enhancing LHb autophagy exerts rapid antidepressant-like effects. LHb autophagy controls neuronal excitability, synaptic transmission and plasticity by means of on-demand degradation of glutamate receptors. Collectively, this study shows a causal role of LHb autophagy in maintaining emotional homeostasis against stress. Disrupted LHb autophagy is implicated in the maladaptation to chronic stress, and its reversal by autophagy enhancers provides a new antidepressant strategy.
Depression, Stress and resilience
Universal photonic artificial intelligence acceleration
Original Paper | Applied optics | 2025-04-08 20:00 EDT
Sufi R. Ahmed, Reza Baghdadi, Mikhail Bernadskiy, Nate Bowman, Ryan Braid, Jim Carr, Chen Chen, Pietro Ciccarella, Matthew Cole, John Cooke, Kishor Desai, Carlos Dorta, Jonathan Elmhurst, Bryce Gardiner, Elliot Greenwald, Shashank Gupta, Parry Husbands, Brian Jones, Anthony Kopa, Ho John Lee, Arulselvan Madhavan, Adam Mendrela, Nicholas Moore, Lakshmi Nair, Aditya Om, Subie Patel, Rutayan Patro, Rob Pellowski, Esha Radhakrishnani, Sandeep Sane, Nicholas Sarkis, Joe Stadolnik, Mykhailo Tymchenko, Gongyu Wang, Kurt Winikka, Alexandra Wleklinski, Josh Zelman, Richard Ho, Ritesh Jain, Ayon Basumallik, Darius Bunandar, Nicholas C. Harris
Over the past decade, photonics research has explored accelerated tensor operations, foundational to artificial intelligence (AI) and deep learning1,2,3,4, as a path towards enhanced energy efficiency and performance5,6,7,8,9,10,11,12,13,14. The field is centrally motivated by finding alternative technologies to extend computational progress in a post-Moore’s law and Dennard scaling era15,16,17,18,19. Despite these advances, no photonic chip has achieved the precision necessary for practical AI applications, and demonstrations have been limited to simplified benchmark tasks. Here we introduce a photonic AI processor that executes advanced AI models, including ResNet3 and BERT20,21, along with the Atari deep reinforcement learning algorithm originally demonstrated by DeepMind22. This processor achieves near-electronic precision for many workloads, marking a notable entry for photonic computing into competition with established electronic AI accelerators23 and an essential step towards developing post-transistor computing technologies.
Applied optics, Mathematics and computing
Recurrent humid phases in Arabia over the past 8 million years
Original Paper | Biogeography | 2025-04-08 20:00 EDT
Monika Markowska, Hubert B. Vonhof, Huw S. Groucutt, Paul S. Breeze, Nick Drake, Mathew Stewart, Richard Albert, Eric Andrieux, James Blinkhorn, Nicole Boivin, Alexander Budsky, Richard Clark-Wilson, Dominik Fleitmann, Axel Gerdes, Ashley N. Martin, Alfredo Martínez-García, Samuel L. Nicholson, Gilbert J. Price, Eleanor M. L. Scerri, Denis Scholz, Nils Vanwezer, Michael Weber, Abdullah M. Alsharekh, Abdul Aziz Al Omari, Yahya S. A. Al-Mufarreh, Faisal Al-Jibreen, Mesfer Alqahtani, Mahmoud Al-Shanti, Iyad Zalmout, Michael D. Petraglia, Gerald H. Haug
The Saharo-Arabian Desert is one of the largest biogeographical barriers on Earth, impeding dispersals between Africa and Eurasia, including movements of past hominins. Recent research suggests that this barrier has been in place since at least 11 million years ago1. In contrast, fossil evidence from the late Miocene epoch and the Pleistocene epoch suggests the episodic presence within the Saharo-Arabian Desert interior of water-dependent fauna (for example, crocodiles, equids, hippopotamids and proboscideans)2,3,4,5,6, sustained by rivers and lakes7,8 that are largely absent from today’s arid landscape. Although numerous humid phases occurred in southern Arabia during the past 1.1 million years9, little is known about Arabia’s palaeoclimate before this time. Here, based on a climatic record from desert speleothems, we show recurrent humid intervals in the central Arabian interior over the past 8 million years. Precipitation during humid intervals decreased and became more variable over time, as the monsoon’s influence weakened, coinciding with enhanced Northern Hemisphere polar ice cover during the Pleistocene. Wetter conditions likely facilitated mammalian dispersals between Africa and Eurasia, with Arabia acting as a key crossroads for continental-scale biogeographic exchanges.
Biogeography, Palaeoclimate
Intersectional analysis for science and technology
Review Paper | Ethics | 2025-04-08 20:00 EDT
Mathias Wullum Nielsen, Elena Gissi, Shirin Heidari, Richard Horton, Kari C. Nadeau, Dorothy Ngila, Safiya Umoja Noble, Hee Young Paik, Girmaw Abebe Tadesse, Eddy Y. Zeng, James Zou, Londa Schiebinger
Intersectionality describes interdependent systems of inequality related to sex, gender, race, age, class and other socio-political dimensions. By focusing on the compounded effects of social categories, intersectional analysis can enhance the accuracy and experimental efficiency of science. Here we extend intersectional approaches that were predominantly developed in the humanities, social sciences and public health to the fields of natural science and technology, where this type of analysis is less established. Informed by diverse global and disciplinary examples–from enhancing facial recognition for diverse user bases to mitigating the disproportionate impact of climate change on marginalized populations–we extract methods to demonstrate how quantitative intersectional analysis functions throughout the research process, from strategic considerations for establishing research priorities to formulating research questions, collecting and analysing data and interpreting results. Our goal is to offer a set of guidelines for researchers, peer-reviewed journals and funding agencies that facilitate systematic integration of intersectional analysis into relevant domains of science and technology. Precision in research best guides effective social and environmental policy aimed at achieving global equity and sustainability.
Ethics, Policy, Scientific community
Multimodal cell maps as a foundation for structural and functional genomics
Original Paper | Data integration | 2025-04-08 20:00 EDT
Leah V. Schaffer, Mengzhou Hu, Gege Qian, Kyung-Mee Moon, Abantika Pal, Neelesh Soni, Andrew P. Latham, Laura Pontano Vaites, Dorothy Tsai, Nicole M. Mattson, Katherine Licon, Robin Bachelder, Anthony Cesnik, Ishan Gaur, Trang Le, William Leineweber, Aji Palar, Ernst Pulido, Yue Qin, Xiaoyu Zhao, Christopher Churas, Joanna Lenkiewicz, Jing Chen, Keiichiro Ono, Dexter Pratt, Peter Zage, Ignacia Echeverria, Andrej Sali, J. Wade Harper, Steven P. Gygi, Leonard J. Foster, Edward L. Huttlin, Emma Lundberg, Trey Ideker
Human cells consist of a complex hierarchy of components, many of which remain unexplored1,2. Here we construct a global map of human subcellular architecture through joint measurement of biophysical interactions and immunofluorescence images for over 5,100 proteins in U2OS osteosarcoma cells. Self-supervised multimodal data integration resolves 275 molecular assemblies spanning the range of 10-8 to 10-5 m, which we validate systematically using whole-cell size-exclusion chromatography and annotate using large language models3. We explore key applications in structural biology, yielding structures for 111 heterodimeric complexes and an expanded Rag-Ragulator assembly. The map assigns unexpected functions to 975 proteins, including roles for C18orf21 in RNA processing and DPP9 in interferon signalling, and identifies assemblies with multiple localizations or cell type specificity. It decodes paediatric cancer genomes4, identifying 21 recurrently mutated assemblies and implicating 102 validated new cancer proteins. The associated Cell Visualization Portal and Mapping Toolkit provide a reference platform for structural and functional cell biology.
Data integration, Machine learning, Network topology, Proteome informatics
Supramolecular docking structure determination of alkyl-bearing molecules
Original Paper | Crystal engineering | 2025-04-08 20:00 EDT
Yitao Wu, Le Shi, Lei Xu, Jiale Ying, Xiaohe Miao, Bin Hua, Zhijie Chen, Jonathan L. Sessler, Feihe Huang
Numerous natural products and drugs contain flexible alkyl chains. The resulting conformational motion can create challenges in obtaining single crystals and thus determining their molecular structures by single-crystal X-ray diffraction (SCXRD)1,2,3,4,5,6,7,8,9,10,11. Here we demonstrate that by using pillar[5]arene-incorporated metal-organic frameworks (MOFs) and taking advantage of pillar[5]arene-alkyl chain host-guest recognition12,13,14,15, it is possible to reduce this motion and bring order to alkyl-chain-containing molecules as the result of docking within accessible pillar[5]arene units present in an overall MOF. This has allowed the single-crystal structures of 48 alkyl-chain-containing molecules, including 6 natural products, 2 approved drugs and 18 custom-made compounds collected from 16 research groups, to be determined using standard SCXRD instrumentation. The structures of alkyl-chain-containing molecules derived from crude reaction products can also be determined directly by SCXRD analyses without further purification. The simplicity, high efficiency and apparent generality of the present pillar[5]arene-incorporated MOF-based supramolecular docking approach suggest that it could emerge as a new tool for the analyses of natural products and drugs that might not be amenable to traditional SCXRD-based structure determination.
Crystal engineering, Metal-organic frameworks
Towards conversational diagnostic artificial intelligence
Original Paper | Diagnosis | 2025-04-08 20:00 EDT
Tao Tu, Mike Schaekermann, Anil Palepu, Khaled Saab, Jan Freyberg, Ryutaro Tanno, Amy Wang, Brenna Li, Mohamed Amin, Yong Cheng, Elahe Vedadi, Nenad Tomasev, Shekoofeh Azizi, Karan Singhal, Le Hou, Albert Webson, Kavita Kulkarni, S. Sara Mahdavi, Christopher Semturs, Juraj Gottweis, Joelle Barral, Katherine Chou, Greg S. Corrado, Yossi Matias, Alan Karthikesalingam, Vivek Natarajan
At the heart of medicine lies physician-patient dialogue, where skillful history-taking enables effective diagnosis, management and enduring trust1,2. Artificial intelligence (AI) systems capable of diagnostic dialogue could increase accessibility and quality of care. However, approximating clinicians’ expertise is an outstanding challenge. Here we introduce AMIE (Articulate Medical Intelligence Explorer), a large language model (LLM)-based AI system optimized for diagnostic dialogue. AMIE uses a self-play-based3 simulated environment with automated feedback for scaling learning across disease conditions, specialties and contexts. We designed a framework for evaluating clinically meaningful axes of performance, including history-taking, diagnostic accuracy, management, communication skills and empathy. We compared AMIE’s performance to that of primary care physicians in a randomized, double-blind crossover study of text-based consultations with validated patient-actors similar to objective structured clinical examination4,5. The study included 159 case scenarios from providers in Canada, the United Kingdom and India, 20 primary care physicians compared to AMIE, and evaluations by specialist physicians and patient-actors. AMIE demonstrated greater diagnostic accuracy and superior performance on 30 out of 32 axes according to the specialist physicians and 25 out of 26 axes according to the patient-actors. Our research has several limitations and should be interpreted with caution. Clinicians used synchronous text chat, which permits large-scale LLM-patient interactions, but this is unfamiliar in clinical practice. While further research is required before AMIE could be translated to real-world settings, the results represent a milestone towards conversational diagnostic AI.
Diagnosis, Medical research
An integrated large-scale photonic accelerator with ultralow latency
Original Paper | Integrated optics | 2025-04-08 20:00 EDT
Shiyue Hua, Erwan Divita, Shanshan Yu, Bo Peng, Charles Roques-Carmes, Zhan Su, Zhang Chen, Yanfei Bai, Jinghui Zou, Yunpeng Zhu, Yelong Xu, Cheng-kuan Lu, Yuemiao Di, Hui Chen, Lushan Jiang, Lijie Wang, Longwu Ou, Chaohong Zhang, Junjie Chen, Wen Zhang, Hongyan Zhu, Weijun Kuang, Long Wang, Huaiyu Meng, Maurice Steinman, Yichen Shen
Integrated photonics, particularly silicon photonics, have emerged as cutting-edge technology driven by promising applications such as short-reach communications, autonomous driving, biosensing and photonic computing1,2,3,4. As advances in AI lead to growing computing demands, photonic computing has gained considerable attention as an appealing candidate. Nonetheless, there are substantial technical challenges in the scaling up of integrated photonics systems to realize these advantages, such as ensuring consistent performance gains in upscaled integrated device clusters, establishing standard designs and verification processes for complex circuits, as well as packaging large-scale systems. These obstacles arise primarily because of the relative immaturity of integrated photonics manufacturing and the scarcity of advanced packaging solutions involving photonics. Here we report a large-scale integrated photonic accelerator comprising more than 16,000 photonic components. The accelerator is designed to deliver standard linear matrix multiply-accumulate (MAC) functions, enabling computing with high speed up to 1 GHz frequency and low latency as small as 3 ns per cycle. Logic, memory and control functions that support photonic matrix MAC operations were designed into a cointegrated electronics chip. To seamlessly integrate the electronics and photonics chips at the commercial scale, we have made use of an innovative 2.5D hybrid advanced packaging approach. Through the development of this accelerator system, we demonstrate an ultralow computation latency for heuristic solvers of computationally hard Ising problems whose performance greatly relies on the computing latency.
Integrated optics, Photonic devices, Silicon photonics
Spatial multi-omics reveals cell-type-specific nuclear compartments
Original Paper | Epigenetics in the nervous system | 2025-04-08 20:00 EDT
Yodai Takei, Yujing Yang, Jonathan White, Isabel N. Goronzy, Jina Yun, Meera Prasad, Lincoln J. Ombelets, Simone Schindler, Prashant Bhat, Mitchell Guttman, Long Cai
The mammalian nucleus is compartmentalized by diverse subnuclear structures. These subnuclear structures, marked by nuclear bodies and histone modifications, are often cell-type specific and affect gene regulation and 3D genome organization1,2,3. Understanding their relationships rests on identifying the molecular constituents of subnuclear structures and mapping their associations with specific genomic loci and transcriptional levels in individual cells, all in complex tissues. Here, we introduce two-layer DNA seqFISH+, which enables simultaneous mapping of 100,049 genomic loci, together with the nascent transcriptome for 17,856 genes and subnuclear structures in single cells. These data enable imaging-based chromatin profiling of diverse subnuclear markers and can capture their changes at genomic scales ranging from 100-200 kilobases to approximately 1 megabase, depending on the marker and DNA locus. By using multi-omics datasets in the adult mouse cerebellum, we showed that repressive chromatin regions are more variable by cell type than are active regions across the genome. We also discovered that RNA polymerase II-enriched foci were locally associated with long, cell-type-specific genes (bigger than 200 kilobases) in a manner distinct from that of nuclear speckles. Furthermore, our analysis revealed that cell-type-specific regions of heterochromatin marked by histone H3 trimethylated at lysine 27 (H3K27me3) and histone H4 trimethylated at lysine 20 (H4K20me3) are enriched at specific genes and gene clusters, respectively, and shape radial chromosomal positioning and inter-chromosomal interactions in neurons and glial cells. Together, our results provide a single-cell high-resolution multi-omics view of subnuclear structures, associated genomic loci and their effects on gene regulation, directly within complex tissues.
Epigenetics in the nervous system, Nuclear organization
Functional connectomics reveals general wiring rule in mouse visual cortex
Original Paper | Extrastriate cortex | 2025-04-08 20:00 EDT
Zhuokun Ding, Paul G. Fahey, Stelios Papadopoulos, Eric Y. Wang, Brendan Celii, Christos Papadopoulos, Andersen Chang, Alexander B. Kunin, Dat Tran, Jiakun Fu, Zhiwei Ding, Saumil Patel, Lydia Ntanavara, Rachel Froebe, Kayla Ponder, Taliah Muhammad, J. Alexander Bae, Agnes L. Bodor, Derrick Brittain, JoAnn Buchanan, Daniel J. Bumbarger, Manuel A. Castro, Erick Cobos, Sven Dorkenwald, Leila Elabbady, Akhilesh Halageri, Zhen Jia, Chris Jordan, Dan Kapner, Nico Kemnitz, Sam Kinn, Kisuk Lee, Kai Li, Ran Lu, Thomas Macrina, Gayathri Mahalingam, Eric Mitchell, Shanka Subhra Mondal, Shang Mu, Barak Nehoran, Sergiy Popovych, Casey M. Schneider-Mizell, William Silversmith, Marc Takeno, Russel Torres, Nicholas L. Turner, William Wong, Jingpeng Wu, Wenjing Yin, Szi-chieh Yu, Dimitri Yatsenko, Emmanouil Froudarakis, Fabian Sinz, Krešimir Josić, Robert Rosenbaum, H. Sebastian Seung, Forrest Collman, Nuno Maçarico da Costa, R. Clay Reid, Edgar Y. Walker, Xaq Pitkow, Jacob Reimer, Andreas S. Tolias
Understanding the relationship between circuit connectivity and function is crucial for uncovering how the brain computes. In mouse primary visual cortex, excitatory neurons with similar response properties are more likely to be synaptically connected1,2,3,4,5,6,7,8; however, broader connectivity rules remain unknown. Here we leverage the millimetre-scale MICrONS dataset to analyse synaptic connectivity and functional properties of neurons across cortical layers and areas. Our results reveal that neurons with similar response properties are preferentially connected within and across layers and areas–including feedback connections–supporting the universality of ‘like-to-like’ connectivity across the visual hierarchy. Using a validated digital twin model, we separated neuronal tuning into feature (what neurons respond to) and spatial (receptive field location) components. We found that only the feature component predicts fine-scale synaptic connections beyond what could be explained by the proximity of axons and dendrites. We also discovered a higher-order rule whereby postsynaptic neuron cohorts downstream of presynaptic cells show greater functional similarity than predicted by a pairwise like-to-like rule. Recurrent neural networks trained on a simple classification task develop connectivity patterns that mirror both pairwise and higher-order rules, with magnitudes similar to those in MICrONS data. Ablation studies in these recurrent neural networks reveal that disrupting like-to-like connections impairs performance more than disrupting random connections. These findings suggest that these connectivity principles may have a functional role in sensory processing and learning, highlighting shared principles between biological and artificial systems.
Extrastriate cortex, Machine learning, Neural circuits, Sensory processing, Striate cortex
Timing and trajectory of BCR::ABL1-driven chronic myeloid leukaemia
Original Paper | Cancer genetics | 2025-04-08 20:00 EDT
Aleksandra E. Kamizela, Daniel Leongamornlert, Nicholas Williams, Xin Wang, Kudzai Nyamondo, Kevin Dawson, Michael Spencer Chapman, Jing Guo, Joe Lee, Karim Mane, Kate Milne, Anthony R. Green, Timothy Chevassut, Peter J. Campbell, Patrick T. Ellinor, Brian J. P. Huntly, E. Joanna Baxter, Jyoti Nangalia
Mutation of some genes drives uncontrolled cell proliferation and cancer. The Philadelphia chromosome in chronic myeloid leukaemia (CML) provided the very first such genetic link to cancer1,2. However, little is known about the trajectory to CML, the rate of BCR::ABL1 clonal expansion and how this affects disease. Using whole-genome sequencing of 1,013 haematopoietic colonies from nine patients with CML aged 22 to 81 years, we reconstruct phylogenetic trees of haematopoiesis. Intronic breaks in BCR and ABL1 were not always observed, and out-of-frame exonic breakpoints in BCR, requiring exon skipping to derive BCR::ABL1, were also noted. Apart from ASXL1 and RUNX1 mutations, extra myeloid gene mutations were mostly present in wild-type cells. We inferred explosive growth attributed to BCR::ABL1 commencing 3-14 years (confidence interval 2-16 years) before diagnosis, with annual growth rates exceeding 70,000% per year. Mutation accumulation was higher in BCR::ABL1 cells with shorter telomere lengths, reflecting their excessive cell divisions. Clonal expansion rates inversely correlated with the time to diagnosis. BCR::ABL1 in the general population mirrored CML incidence, and advanced and/or blast phase CML was characterized by subsequent genomic evolution. These data highlight the oncogenic potency of BCR::ABL1 fusion and contrast with the slow and sequential clonal trajectories of most cancers.
Cancer genetics, Evolutionary genetics, Haematological cancer, Phylogenomics
Nature Materials
Enhanced energy storage in high-entropy ferroelectric polymers
Original Paper | Ferroelectrics and multiferroics | 2025-04-08 20:00 EDT
Chenyi Li, Yang Liu, Bo Li, Ze Yuan, Tiannan Yang, Yuquan Liu, Hanxiao Gao, Linxiao Xu, Xiang Yu, Quan Luo, Shengfei Tang, Minghai Yao, Yutie Gong, Zekai Fei, Long-Qing Chen, Haibo Zhang, Huamin Zhou, Qing Wang
Relaxor ferroelectrics have been intensively studied during the past two decades for capacitive energy storage in modern electronics and electrical power systems. However, the energy density of relaxor ferroelectrics is fundamentally limited by early polarization saturation and largely reduced polarization despite high dielectric constants. To overcome this challenge, here we report the formation of a high-entropy superparaelectric phase in relaxor ferroelectric polymers induced by low-dose proton irradiation, which exhibits delayed polarization saturation, reduced ferroelectric loss and markedly improved polarizability. Our combined theoretical and experimental results reveal that new chemical bonds generated by the irradiation-induced chemical reactions are essential to the formation of the high-entropy state in ferroelectric polymers. The high-entropy superparaelectric phase endows the polymer with a substantially enhanced intrinsic energy density of 45.7 J cm-3 at room temperature, outperforming the current ferroelectric polymers and nanocomposites under the same electric field. Our work widens the high-entropy concept in ferroelectrics and lays the foundation for the future exploration of high-performance ferroelectric polymers.
Ferroelectrics and multiferroics
DNA photofluids show life-like motion
Original Paper | DNA nanomachines | 2025-04-08 20:00 EDT
Qi-Hong Zhao, Jin-Ying Qi, Nan-Nan Deng
As active matter, cells exhibit non-equilibrium structures and behaviours such as reconfiguration, motility and division. These capabilities arise from the collective action of biomolecular machines continuously converting photoenergy or chemical energy into mechanical energy. Constructing similar dynamic processes in vitro presents opportunities for developing life-like intelligent soft materials. Here we report an active fluid formed from the liquid-liquid phase separation of photoresponsive DNA nanomachines. The photofluids can orchestrate and amplify nanoscale mechanical movements by orders of magnitude to produce macroscopic cell-like behaviours including elongation, division and rotation. We identify two dissipative processes in the DNA droplets, photoalignment and photofibrillation, which are crucial for harnessing stochastic molecular motions cooperatively. Our results demonstrate an active liquid molecular system that consumes photoenergy to create ordered out-of-equilibrium structures and behaviours. This system may help elucidate the physical principles underlying cooperative motion in active matter and pave the way for developing programmable interactive materials.
DNA nanomachines, Fluids, Organizing materials with DNA, Self-assembly
Physical Review Letters
Transition of Anticoncentration in Gaussian Boson Sampling
Research article | Boson sampling | 2025-04-08 06:00 EDT
Adam Ehrenberg, Joseph T. Iosue, Abhinav Deshpande, Dominik Hangleiter, and Alexey V. Gorshkov
Gaussian boson sampling is a promising method for experimental demonstrations of quantum advantage because it is easier to implement than other comparable schemes. While most of the properties of Gaussian boson sampling are understood to the same degree as for these other schemes, we understand relatively little about the statistical properties of its output distribution. The most relevant statistical property, from the perspective of demonstrating quantum advantage, is the ‘’anticoncentration’’ of the output distribution as measured by its second moment. The degree of anticoncentration features in arguments for the complexity-theoretic hardness of Gaussian boson sampling. In this Letter, we develop a graph-theoretic framework for analyzing the moments of the Gaussian boson sampling distribution. Using this framework, we show that Gaussian boson sampling undergoes a transition in anticoncentration as a function of the number of modes that are initially squeezed compared to the number of photons measured at the end of the circuit. When the number of initially squeezed modes scales sufficiently slowly with the number of photons, there is a lack of anticoncentration. However, if the number of initially squeezed modes scales quickly enough, the output probabilities anticoncentrate weakly.
Phys. Rev. Lett. 134, 140601 (2025)
Boson sampling, Quantum algorithms & computation, Quantum information processing with continuous variables, Quantum information theory, Quantum simulation
Dimming Starlight with Dark Compact Objects
Research article | Dark matter | 2025-04-08 06:00 EDT
Joseph Bramante, Melissa D. Diamond, and J. Leo Kim
Compact objects formed from dark matter could be detected by examining the dimming of background light when the dark objects pass across the line of sight with Earth.

Phys. Rev. Lett. 134, 141001 (2025)
Dark matter, Massive compact halo objects, Particle astrophysics, Particle dark matter
Adatom Engineering Magnetic Order in Superconductors: Applications to Altermagnetic Superconductivity
Research article | Altermagnetism | 2025-04-08 06:00 EDT
Lucas V. Pupim and Mathias S. Scheurer
Arranging nonmagnetic atoms on the surface of an unconventional superconductor could induce a novel phenomenon called altermagnetic superconductivity.

Phys. Rev. Lett. 134, 146001 (2025)
Altermagnetism, Berry curvature, Spin-orbit coupling, Spin-singlet pairing, Superconductivity, d-wave, s-wave, Superlattices
Doping Dependence of 2-Spinon Excitations in the Doped 1D Cuprate ${\mathrm{Ba}}{2}{\mathrm{CuO}}{3+\delta }$
Research article | 1-dimensional spin chains | 2025-04-08 06:00 EDT
Jiarui Li, Daniel Jost, Ta Tang, Ruohan Wang, Yong Zhong, Zhuoyu Chen, Mirian Garcia-Fernandez, Jonathan Pelliciari, Valentina Bisogni, Brian Moritz, Kejin Zhou, Yao Wang, Thomas P. Devereaux, Wei-Sheng Lee, and Zhi-Xun Shen
Recent photoemission experiments on the quasi-one-dimensional Ba-based cuprates suggest that doped holes experience an attractive potential not captured using the simple Hubbard model. This observation has garnered significant attention due to its potential relevance to Cooper pair formation in high-${T}{c}$ cuprate superconductors. To scrutinize this assertion, we examined signatures of such an attractive potential in doped 1D cuprates ${\mathrm{Ba}}{2}{\mathrm{CuO}}{3+\delta }$ by measuring the dispersion of the 2-spinon excitations using Cu ${L}{3}$-edge resonant inelastic x-ray scattering (RIXS). Upon doping, the 2-spinon excitations appear to weaken, with a shift of the minimal position corresponding to the nesting vector of the Fermi points, ${q}_{F}$. Notably, we find that the energy scale of the 2-spinons near the Brillouin zone boundary is substantially softened compared to that predicted by the Hubbard model in one dimension. Such a discrepancy implies missing ingredients, which lends support for the presence of an additional attractive potential between holes.
Phys. Rev. Lett. 134, 146501 (2025)
1-dimensional spin chains, Cuprates, High-temperature superconductors, Strongly correlated systems, Resonant inelastic x-ray scattering
Physical Review X
Bulk Superconductivity in Pressurized Trilayer Nickelate ${\mathrm{Pr}}{4}{\mathrm{Ni}}{3}{\mathrm{O}}_{10}$ Single Crystals
Research article | Superconducting phase transition | 2025-04-08 06:00 EDT
Enkang Zhang, Di Peng, Yinghao Zhu, Lixing Chen, Bingkun Cui, Xingya Wang, Wenbin Wang, Qiaoshi Zeng, and Jun Zhao
The discovery of bulk superconductivity in pressurized single crystals of Pr₄Ni₃O₁₀ establishes trilayer nickelates as genuine bulk high-temperature superconductors.

Phys. Rev. X 15, 021008 (2025)
Superconducting phase transition, Superconductivity, Superconductors, High-temperature superconductors, Strongly correlated systems, Crystal growth
Synthetic High Angular Momentum Spin Dynamics in a Microwave Oscillator
Research article | Quantum circuits | 2025-04-08 06:00 EDT
Saswata Roy, Alen Senanian, Christopher S. Wang, Owen C. Wetherbee, Luojia Zhang, B. Cole, C. P. Larson, E. Yelton, Kartikeya Arora, Peter L. McMahon, B. L. T. Plourde, Baptiste Royer, and Valla Fatemi
A new control scheme simplifies quantum harmonic oscillator manipulation, linking control parameters to quantum behavior. It enables spin-like behavior for novel quantum information processing.

Phys. Rev. X 15, 021009 (2025)
Quantum circuits, Quantum control, Quantum harmonic oscillator, Quantum simulation
arXiv
Constrained Search in Imaginary Time
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Markus Penz, Robert van Leeuwen
An optimization method for the expectation value of a self-adjoint operator under a finite number of expectation-value constraints based on imaginary-time evolution is introduced. It is formulated for finite-dimensional Hilbert spaces and uses linearly independent and commuting self-adjoint operators for the constraints. The method is applied to the problem of finding the universal functional of density-functional theory and allows theoretical insights into the density-potential mapping.
Materials Science (cond-mat.mtrl-sci), Optimization and Control (math.OC), Chemical Physics (physics.chem-ph), Quantum Physics (quant-ph)
First-passage properties of the jump process with a drift. Two exactly solvable cases
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-09 20:00 EDT
Ivan N. Burenev, Satya N. Majumdar
We investigate the first-passage properties of a jump process with a constant drift, focusing on two key observables: the first-passage time $ \tau$ and the number of jumps $ n$ before the first-passage event. By mapping the problem onto an effective discrete-time random walk, we derive an exact expression for the Laplace transform of the joint distribution of $ \tau$ and $ n$ using the generalized Pollaczek-Spitzer formula. This result is then used to analyze the first-passage properties for two exactly solvable cases: (i) both the inter-jump intervals and jump amplitudes are exponentially distributed, and (ii) the inter-jump intervals are exponentially distributed while all jumps have the same fixed amplitude. We show the existence of two distinct regimes governed by the strength of the drift: (i) a survival regime, where the process remains positive indefinitely with finite probability; (ii) an absorption regime, where the first-passage eventually occurs; and (iii) a critical point at the boundary between these two phases. We characterize the asymptotic behavior of survival probabilities in each regime: they decay exponentially to a constant in the survival regime, vanish exponentially fast in the absorption regime, and exhibit power-law decay at the critical point. Furthermore, in the absorption regime, we derive large deviation forms for the marginal distributions of $ \tau$ and n. The analytical predictions are validated through extensive numerical simulations.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph), Probability (math.PR)
50 pages, 16 figures
Realizing Scalable Chemical Vapour Deposition of Monolayer Graphene Films on Iron with Concurrent Surface Hardening by in situ Observations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Bernhard Fickl, Werner Artner, Daniel Matulka, Jakob Rath, Martin Nastran, Markus Hofer, Raoul Blume, Michael Hävecker, Alexander Kirnbauer, Florian Fahrnberger, Herbert Hutter, Dengsong Zhang, Paul H. Mayrhofer, Axel Knop-Gericke, Beatriz Roldan Cuenya, Robert Schlögl, Christian Dipolt, Dominik Eder, Bernhard C. Bayer
Graphene has been suggested as an ultimately thin functional coating for metallurgical alloys such as steels. However, even on pure iron (Fe), the parent phase of steels, growth of high quality graphene films remains largely elusive to date. We here report scalable chemical vapour deposition (CVD) of high quality monolayer graphene films on Fe substrates. To achieve this, we here elucidate the mechanisms of graphene growth on Fe using complementary in situ X-ray diffractometry (XRD) and in situ near ambient pressure X-ray photoelectron spectroscopy (NAP XPS) during our scalable CVD conditions. As key factors that set Fe apart from other common graphene CVD catalyst supports such as Ni or Cu, we identify that for Fe (i) carbothermal reduction of persistent Fe-oxides and (ii) kinetic balancing of carbon uptake into the Fe during CVD near the Fe-C eutectoid because of the complex multi-phased Fe-C phase diagram are critical. Additionally, we establish that the carbon uptake into the Fe during graphene CVD is not only important in terms of growth mechanism but can also be advantageously utilized for concurrent surface hardening of the Fe during the graphene CVD process akin to carburization/case hardening. Our work thereby forms a framework for controlled and scalable high-quality monolayer graphene film CVD on Fe incl. the introduction of concurrent surface hardening during graphene CVD.
Materials Science (cond-mat.mtrl-sci)
Flux attachment theory of fractional excitonic insulators
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-09 20:00 EDT
Steven Gassner, Ady Stern, C. L. Kane
The search for fractional quantized Hall phases in the absence of a magnetic field has primarily targeted flat-band systems that mimic the features of a Landau level. In an alternative approach, the fractional excitonic insulator (FEI) has been proposed as a correlated electron-hole fluid that arises near a band inversion between bands of different angular momentum with strong interactions. It remains an interesting challenge to find Hamiltonians with realistic interactions that stabilize this state. Here, we describe composite boson and composite fermion theories that highlight the importance of $ (p_x+ip_y)^m$ excitonic pairing in stabilizing FEIs in a class of band inversion models. We predict a sequence of Jain-like and Laughlin-like FEI states, the simplest of which has the topological order of the bosonic $ \nu=1/2$ fractional quantized Hall state. We discuss implications for recent numerical studies on a chiral spin liquid phase in interacting Chern insulator models.
Strongly Correlated Electrons (cond-mat.str-el)
Investigating electron conductivity regimes in the bacterial cytochrome wire OmcS
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
3. L.N. Mohanam, R. Umeda, L. Gu, Y. Song, D.J. Tobias, A.I. Hochbaum, R. Wu, S. Sharifzadeh
The anaerobic bacterium \textit{Geobacter sulfurreducens} produces extracellular, electronically conductive cytochrome polymer wires that are conductive over micron length scales. Structure models from cryo-electron microscopy data show OmcS wires form a linear chain of hemes along the protein wire axis, which is proposed as the structural basis supporting their electronic properties. The geometric arrangement of heme along OmcS wires is conserved in many multiheme c-type cytochromes and other recently discovered microbial cytochrome wires. However, the mechanism by which this arrangement of heme molecules support electron transport through proteins and supramolecular heme wires is unclear. Here, we investigate the site energies, inter-heme coupling, and long-range electronic conductivity within OmcS. We introduce an approach to extract charge carrier site information directly from Kohn-Sham density functional theory, without employing projector schemes. We show that site and coupling energies are highly sensitive to changes in inter-heme geometry and the surrounding electrostatic environment, as intuitively expected. These parameters serve as inputs for a quantum charge carrier model that includes decoherence corrections with which we predict a diffusion coefficient comparable with other organic-based electronic materials. Based on these simulations, we propose that dynamic disorder, particularly due to perturbative inter-heme vibrations allow the carrier to overcome trapping due to the presence of static disorder \textit{via} small frequency-dependent fluctuations. These studies provide insights into molecular and electronic determinants of long-range electronic conductivity in microbial cytochrome wires and highlight design principles for bioinspired, heme-based conductive materials.
Materials Science (cond-mat.mtrl-sci)
Field-tunable quantum disordered ground state in the triangular-lattice antiferromagnet TlYbSe2
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-09 20:00 EDT
Bishnu P. Belbase, Arjun Unnikrishnan, Eun Sang Choi, Arnab Banerjee
We introduce the triangular-lattice antiferromagnet TlYbSe2 belonging to the rare-earth delafossite family with a relatively disorder-free frustrated triangular lattice - extending the search for the quintessential chiral quantum spin liquid state. While DC magnetization suggests magnetic exchange interactions in the order of several kelvin, the zero-field AC magnetization and heat capacity measurements reveal no signs of long-range magnetic order down to 20 mK, indicating a highly frustrated quantum-disordered ground state. The high-field AC magnetization reveals a phase diagram generally consistent with a large family of Yb delafossites. We observe a spin glass transition around 35 mK at zero field, which we argue is due to free spins. A broad anomaly in the heat capacity measurements between 2 - 5 K - indicative of short-range spin correlations - along with a linear temperature dependence at low temperatures and the complete absence of long-range order at low fields, establishes the low-temperature, low-field regime of TlYbSe2 as a prime location for exploring field-tunable QSL behavior.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other), Quantum Physics (quant-ph)
Data-Driven Molecular Dynamics and TEM Analysis of Platinum Crystal Growth on Graphene and Reactive Hydrogen-Sensing Dynamics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Akram Ibrahim, Ahmed M. Hafez, Mahmooda Sultana, Can Ataca
Pt-functionalized graphene harnesses graphene’s exceptional carrier mobility with Pt’s catalytic activity for hydrogen sensing, yet the mechanisms of Pt crystal growth, its interaction with graphene, and the consequent impact on hydrogen sensitivity remain incompletely understood. We develop a high-fidelity equivariant machine-learned interatomic potential (MLIP) to perform large-scale molecular dynamics (MD) simulations with near-density functional theory (DFT) accuracy. Our simulations capture key growth stages-including Pt nucleation, coalescence, and the formation of either polycrystalline clusters or epitaxial thin films-under varying deposition loadings and rates. Transmission electron microscopy and Raman measurements validate the predicted morphologies, revealing small approximately spherical clusters at lower Pt loadings that evolve into slightly thicker, more planar domains with increased loading. Reactive MD shows hydrogen dissociates predominantly on Pt nanostructures at room temperature, with minimal spillover onto pristine graphene. Furthermore, hydrogen uptake increases with Pt loading at a diminishing rate, while reaction kinetics are significantly faster at lower coverages and rapidly decline with increasing loading. DFT calculations indicate undercoordinated Pt clusters induce $ n$ -type doping in graphene, which is diminished when hydrogen adsorption depletes Pt electron density, thereby transducing the adsorption events from Pt-surfaces to the Pt-graphene interface. By correlating deposition conditions, nanostructure morphology, and hydrogen sensing dynamics, our findings suggest that moderate Pt loadings can effectively balance sufficient doping with a pronounced Pt-mediated electronic response to graphene. These insights underscore the importance of combining DFT and MLIP simulations with experiments to guide next-generation chemiresistive gas sensor design.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn), Chemical Physics (physics.chem-ph)
QARPET: A Crossbar Chip for Benchmarking Semiconductor Spin Qubits
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
Alberto Tosato, Asser Elsayed, Federico Poggiali, Lucas Stehouwer, Davide Costa, Karina Hudson, Davide Degli Esposti, Giordano Scappucci
Large-scale integration of semiconductor spin qubits into industrial quantum processors hinges on the ability to characterize the performance of quantum components at scale. While the semiconductor industry has addressed scalable testing for transistors using device matrix arrays, extending this approach to quantum dot spin qubits is challenged by their operation at sub-kelvin temperatures, in the presence of magnetic fields, and by the use of radio-frequency signals. Here, we present QARPET (Qubit-Array Research Platform for Engineering and Testing), a scalable architecture for characterizing spin qubits using a quantum dot crossbar array with sublinear scaling of interconnects. The crossbar features tightly pitched (1 {\mu}m), individually addressable spin qubit tiles and is implemented in planar germanium, by fabricating a large device with the potential to host 1058 hole spin qubits. We focus our measurements on a patch of 40 tiles and demonstrate key device functionality at millikelvin temperature including unique tile addressability, threshold voltage and charge noise statistics, and characterisation of hole spin qubits and their coherence times in a single tile. These demonstrations pave the way for a new generation of quantum devices designed for the statistical characterisation of spin qubits and for developing automated routines for quantum dot tuning and spin qubit operation.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Contact theorems for electrolyte-filled hollow charged nanoparticles: Non-linear osmotic pressure in confined electrolytes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-09 20:00 EDT
Marcelo Lozada-Cassou, Sócrates Aníbal Rivera-Cerecero
Analytical expressions for the osmotic pressure of electrolytes confined within electrolyte-filled, hollow, charged nanoparticles are studied using contact theorems for cavity nanoshells immersed in a low-concentration electrolyte. Three shell geometries are considered: planar, cylindrical, and spherical. The nanoparticles are modeled as charged cavities of internal radius R and wall thickness d, and are assumed to be at infinite dilution in the surrounding bulk electrolyte. Numerical calculations of the osmotic pressure are presented as a function of several model parameters. For cylindrical and spherical shells, the osmotic pressure exhibits absolute maxima as a function of shell size. This behavior arises from the competition between the violation of the local electroneutrality condition (VLEC) within the shell cavity and the nonlinear profile of the effective electric field. In contrast, the osmotic pressure of the planar (slit-shell) geometry is a monotonic, nonlinear, decreasing function of cavity width. The results are analyzed in terms of the steric and electrostatic (Maxwell stress tensor) contributions appearing in the corresponding contact theorems. Because the analysis is restricted to low surface charge densities and low electrolyte concentrations, the electric double layers (EDLs) inside and outside the shells are obtained from analytical solutions of the linearized Poisson-Boltzmann equation. We report two novel phenomena: confinement charge reversal (CCR) and confinement overcharging (CO). These arise naturally from the topology of the system. By construction, the confined and bulk electrolytes are maintained at the same chemical potential. These findings have implications for the design of synthetic nanocapsules and ion-selective membranes.
Soft Condensed Matter (cond-mat.soft)
60 pages, 11 figures
Electron-magnon dynamics triggered by an ultrashort laser pulse: A real-time Dual $GW$ study
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-09 20:00 EDT
Nagamalleswararao Dasari, Hugo U. R. Strand, Martin Eckstein, Alexander I. Lichtenstein, Evgeny A. Stepanov
Ultrafast irradiation of correlated electronic systems triggers complex dynamics involving quasi-particle excitations, doublons, charge carriers, and spin fluctuations. To describe these effects, we develop an efficient non-equilibrium approach, dubbed D-$ GW$ , that enables a self-consistent treatment of local correlations within dynamical mean-field theory (DMFT) and spatial charge and spin fluctuations, that are accounted for simultaneously within a diagrammatic framework. The method is formulated in the real-time domain and provides direct access to single- and two-particle momentum- and energy-dependent response functions without the need for analytical continuation, which is required in Matsubara frequency-based approaches. We apply the D-$ GW$ method to investigate the dynamics of a photo-excited extended Hubbard model, the minimal system that simultaneously hosts strong charge and spin fluctuations. Focusing on the challenging parameter regime near the Mott transition, we demonstrate that correlated metals and narrow-gap Mott insulators undergo distinct thermalization processes involving complex energy transfer between single-particle and collective electronic excitations.
Strongly Correlated Electrons (cond-mat.str-el)
21 pages, 13 figures
Randomly measured quantum particle
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-04-09 20:00 EDT
We consider the motion of a quantum particle whose position is measured in random places at random moments in time. We show that a freely moving particle measured in this way undergoes superdiffusion, while a charged particle moving in a magnetic field confined to the lowest Landau level undergoes conventional diffusion. We also look at a particle moving in one dimensional space in a random time-independent potential, so that it is Anderson localized, which is also measured at random points in space and randomly in time. We find that random measurements break localization and this particle also undergoes diffusion. To address these questions, we develop formalism similar to that employed when studying classical and quantum problems with time-dependent noise.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Physics (quant-ph)
5 pages
Magnetic polaron formation in EuZn$_2$P$_2$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-09 20:00 EDT
Matthew S. Cook, Elizabeth A. Peterson, Caitlin S. Kengle, E. R. Kennedy, J. Sheeran, Clément Girod, G.S. Freitas, Samuel M. Greer, Peter Abbamonte, P.G. Pagliuso, J. D. Thompson, Sean M. Thomas, P. F. S. Rosa
Colossal magnetoresistance (CMR) has been observed across many Eu$ ^{2+}$ -based materials; however, its origin is not completely understood. Here we investigate the antiferromagnetic insulator EuZn$ _2$ P$ _2$ through single crystal x-ray diffraction, transmission electron microscopy, electrical transport, magnetization, dilatometry, and electron spin resonance measurements complemented by density functional theory calculations. Our electrical resistivity data reveal a large negative magnetoresistance, $ MR = [R(H)-R(0)]/R(0)$ , that reaches $ MR = -99.7%$ at 9~T near the antiferromagnetic ordering temperature $ T_N=23\ \text{K}$ . Dilatometry measurements show an accompanying field-induced lattice strain. Additionally, Eu$ ^{2+}$ electron spin resonance reveals a strong ferromagnetic exchange interaction between Eu$ ^{2+}$ and conduction electrons. Our experimental results in EuZn$ _2$ P$ _2$ are consistent with a magnetic polaron scenario and suggest magnetic polaron formation as a prevailing explanation of CMR in Eu$ ^{2+}$ -based compounds.
Strongly Correlated Electrons (cond-mat.str-el)
Tailoring Charge-Transfer at Metal-Organic Interfaces Using Designer Shockley Surface States
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Anubhab Chakraborty, Oliver L.A. Monti
Metal-organic interfaces determine critical processes in organic electronic devices. The frontier molecular orbitals (highest occupied and lowest unoccupied molecular orbital, HOMO and LUMO) are crucial in determining charge-injection and -collection processes into and from the organic semiconductor films. Here we show that we are able to tune the interfacial electronic structure of a strongly interacting interfacial system formed by adsorption of the electron acceptor 1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile (HATCN, C18N12) on Ag thin films on Cu(111). The thickness-dependent Shockley surface state emerging on this layered metallic system couples to the LUMO, which allows precise control over the energetic position and filling of the charge-transfer interface state relative to the Fermi level (EF). Our ability to tune the interfacial electronic structure while maintaining the structure of the molecular film represents an important step towards designing organic semiconductor interfaces.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Dial It Down: The Effect of Strongly Interacting Adsorbates on the BiAg2 Rashba Surface State
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Anubhab Chakraborty, Torsten Fritz, Percy Zahl, Oliver L.A. Monti
Organic semiconductors interfaced with spin-orbit coupled materials offer a rich playground for fundamental studies of controlling spin dynamics in spintronic devices. The adsorbate-surface interactions at such interfaces play a key role in determining the valence electronic and spin structure and consequently, the device physics as well. Here we present the adsorption and electronic structure of the strong organic electron acceptor 2,7-dinitropyrene-4,5,9,10-tetrone (NO2-PyT, C16H4N2O8) on the Rashba spin-orbit coupled surface alloy BiAg2/Ag(111). We show that the strong adsorbate-surface alloy interaction leads to weakening of the electronic coupling between the surface alloy atoms and quench the spin-orbit coupled surface state in BiAg2/Ag(111). Our findings demonstrate an important challenge associated with using molecular adsorbates to tailor the spin polarization in BiAg2/Ag(111), and our work provides guidelines to consider while designing interfacial systems to engineer the spin polarization in Rashba surface alloys.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Towards “on-demand” van der Waals epitaxy with hpc-driven online ensemble sampling
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Soumendu Bagchi, Ankita Biswas, Prasanna V. Balachandran, Ayana Ghosh, Panchapakesan Ganesh
Traditional approaches to achieve targeted epitaxial growth involves exploring a vast parameter space of thermodynamical and kinetic drivers (e.g., temperature, pressure, chemical potential etc). This tedious and time-consuming approach becomes particularly cumbersome to accelerate synthesis and characterization of novel materials with complex dependencies on local chemical environment, temperature and lattice-strains, specifically nanoscale heterostructures of layered 2D materials. We combine the strength of next generation supercomputers at the extreme scale, machine learning and classical molecular dynamics simulations within an adaptive real time closed-loop virtual environment steered by Bayesian optimization to enable asynchronous ensemble sampling of the synthesis space, and apply it to the recrystallization phenomena of amorphous transition-metal dichalcogenide (TMDC) bilayer to form stack moiré heterostructures under various growth parameters. We show that such asynchronous ensemble sampling frameworks for materials simulations can be promising towards achieving on-demand epitaxy of van der Waals stacked moiré devices, paving the way towards a robust autonomous materials synthesis pipeline to enable unprecedented discovery of new functionalities.
Materials Science (cond-mat.mtrl-sci)
Fast and direct preparation of a genuine lattice BEC via the quantum Mpemba effect
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-09 20:00 EDT
Philipp Westhoff, Sebastian Paeckel, Mattia Moroder
We present an efficient method for dissipatively preparing a Bose-Einstein condensate (BEC) directly on a lattice, avoiding the need for a two-staged preparation procedure currently used in ultracold atom platforms. Our protocol is based on driving the lattice-subsystem into a non-equilibrium steady state, which we show to exhibit a lattice analog of a true BEC, where the depletion can be controlled via the dissipation strength. Furthermore, exploiting a symmetry-based Mpemba effect, we analytically identify a class of simple, experimentally-realizable states that converge exponentially faster to the steady state than typical random initializations. We also show how to tune the momentum of the created high-fidelity BEC by combining superfluid immersion with lattice shaking. Our theoretical predictions are confirmed by numerical simulations of the dissipative dynamics, quantitatively assessing the speedups yielded by our protocol, as well as the fidelities of the prepared BEC.
Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
6+9 pages, 3+6 figures
Thermoelectric transport through a Majorana zero modes interferometer
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
Alejandro P. Garrido, David Zambrano, Juan Pablo ramos, Pedro Orellana
In this study, we examine the thermoelectric characteristics of a system consisting of two topological superconducting nanowires, each exhibiting Majorana zero modes at their ends, connected to leads within an interferometer configuration. By employing Green’s function formalism, we derive the spectral properties and transport coefficients. Our findings indicate that bound states in the continuum (BICs) manifest in symmetric setups, influenced by the length of the wires and coupling parameters. Deviations of the magnetic flux from specific values transform BICs into quasi-BICs with finite width, resulting in conductance antiresonances. The existence and interplay of Majorana zero modes enhance thermoelectric performance in asymmetric configurations. Modulating the magnetic flux transitions BICs into quasi-BICs significantly enhances the Seebeck coefficient and figure of merit, thereby proposing a strategy for optimizing thermoelectric efficiency in systems based on Majorana zero modes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
Cross-functional transferability in universal machine learning interatomic potentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Xu Huang, Bowen Deng, Peichen Zhong, Aaron D. Kaplan, Kristin A. Persson, Gerbrand Ceder
The rapid development of universal machine learning interatomic potentials (uMLIPs) has demonstrated the possibility for generalizable learning of the universal potential energy surface. In principle, the accuracy of uMLIPs can be further improved by bridging the model from lower-fidelity datasets to high-fidelity ones. In this work, we analyze the challenge of this transfer learning problem within the CHGNet framework. We show that significant energy scale shifts and poor correlations between GGA and r$ ^2$ SCAN pose challenges to cross-functional data transferability in uMLIPs. By benchmarking different transfer learning approaches on the MP-r$ ^2$ SCAN dataset of 0.24 million structures, we demonstrate the importance of elemental energy referencing in the transfer learning of uMLIPs. By comparing the scaling law with and without the pre-training on a low-fidelity dataset, we show that significant data efficiency can still be achieved through transfer learning, even with a target dataset of sub-million structures. We highlight the importance of proper transfer learning and multi-fidelity learning in creating next-generation uMLIPs on high-fidelity data.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
Entropic modulation of divalent cation transport through porous two-dimensional materials
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
Yechan Noh, Demian Riccardi, Alex Smolyanitsky
Aqueous cations permeate subnanoscale pores in two-dimensional materials by crossing free energy barriers dominated by competing enthalpic contributions from transiently decreased ion-solvent and increased ion-pore electrostatic interactions. This commonly accepted view is rooted in the studies of \textit{monovalent} cation transport. Divalent cations, however, have significantly higher desolvation costs, requiring considerably larger pores to enable retention of the first hydration shell and subsequently transport. We show that this scenario gives rise to a strong enthalpy-entropy competition. More specifically, the first hydration shell is shown to undergo rotational ordering inside the pore, resulting in a tight transition state with an entropic cost of order $ 9k_BT$ . Our results shed light on the basic mechanisms of transport barrier formation for aqueous divalent cations permeating nanoporous 2D membranes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
main text (5 pages, 4 figures) and supplementary material (8 pages, 6 figures)
Electron-Hole Separation Dynamics and Optoelectronic Properties of a PCE10:FOIC Blend
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
G. Ammirati, S. Turchini, F. Toschi, P. O Keeffe, A. Paladini, G. Mattioli, P. Moras, P. M. Sheverdyaeva, V. Milotti, C. J. Brabec, M. Wagner, I. McCulloch, A. Di Carlo, D. Catone
Understanding charge separation dynamics in organic semiconductor blends is crucial for optimizing the performance of organic photovoltaic solar cells. In this study, we explored the optoelectronic properties and charge separation dynamics of a PCE10:FOIC blend, by combining steady-state and time-resolved spectroscopies with high-level DFT calculations. Femtosecond transient absorption spectroscopy revealed a significant reduction of the exciton-exciton annihilation recombination rate in the acceptor when incorporated into the blend, compared to its pristine form. This reduction was attributed to a decrease in exciton density within the acceptor, driven by an efficient hole-separation process that was characterized by following the temporal evolution of the transient signals associated with the excited states of the donor when the acceptor was selectively excited within the blend. The analysis of these dynamics enabled the estimation of the hole separation time constant from the acceptor to the donor, yielding a time constant of (1.3 +- 0.3) ps. Additionally, this study allowed the quantification of exciton diffusion and revealed a charge separation efficiency of approximately 60%, providing valuable insights for the design of next-generation organic photovoltaic materials with enhanced charge separation and improved device efficiency.
Materials Science (cond-mat.mtrl-sci)
Interfacial Heat Transport via Evanescent Radiation by Hot Electrons
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
William D. Hutchins, Saman Zare, Mehran Habibzadeh, Sheila Edalatpour, Patrick E. Hopkins
We predict an additional thermal transport pathway across metal/non-metal interfaces with large electron-phonon non-equilibrium via evanescent radiative heat transfer. In such systems, electron scattering processes vary drastically and can be leveraged to guide heat across interfaces via radiative heat transport without engaging the lattice directly. We employ the formalism of fluctuational electrodynamics to simulate the spectral radiative heat flux across the interface of a metal film and a non-metal substrate. We find that the radiative conductance can exceed 300 MW m$ ^{-2}$ K$ ^{-1}$ at an electron temperature of 5000 K for an emitting tungsten film on a hexagonal boron nitride substrate, becoming comparable to its conductive counterpart. This allows for a more holistic approach to the heat flow across interfaces, accounting for electron-phonon non-equilibrium and ultrafast near-field phonon-polariton coupling.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Computational Physics (physics.comp-ph)
Synthesis, crystal and electronic structures, and second harmonic generation of La 4Ge 3S12
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Hiroya Ohtsuki, Suguru Nakata, Yu Yamane, Ryunosuke Takahashi, Koichi Kusakabe, Hiroki Wadati
The crystal structure of La 4 Ge 3S 12 has been known to be noncentrosymmetric for almost four decades. This characteristic inversion symmetry breaking suggests the presence of nonlinear optical properties. Yet only recently have nonlinear optical phenomena such as second harmonic generation (SHG) been reported in this material. In this study, we synthesized La4Ge3S12 using the direct reaction method and characterized the composition, crystal structure, and electronic structure using electron probe microanalysis, powder and single-crystal X-ray diffraction, and X-ray photoelectron spectroscopy. The experimentally measured electronic structure is in line with that obtained using first-principles calculations. In addition, we observed the nonlinear optical properties of La4Ge3S12 in response to an ultrashort infrared pulsed laser. We found that the intensity of the SHG depends quadratically on the intensity of the incident light, mirroring the intrinsic nature of nonlinear optics.
Materials Science (cond-mat.mtrl-sci)
Accepted for publication in ZAAC (7 pages, 8 figures)
Influence of doping on non-equilibrium carrier dynamics in graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
Leonard Weigl, Johannes Gradl, Peter Richter, Thomas Seyller, Domenica Convertino, Stiven Forti, Camilla Coletti, Isabella Gierz
Controlling doping is key to optimizing graphene for high-speed electronic and optoelectronic devices. However, its impact on non-equilibrium carrier lifetimes remains debated. Here, we systematically tune the doping level of quasi-freestanding epitaxial graphene on SiC(0001) via potassium deposition and probe its ultrafast carrier dynamics directly in the band structure using time- and angle-resolved photoemission spectroscopy (trARPES). We find that increased doping lowers both the peak electronic temperature and the cooling rate of Dirac carriers, which we attribute to higher electronic heat capacity and reduced phonon emission phase space. Comparing quasi-freestanding graphene with graphene on a carbon buffer layer reveals faster relaxation in the latter, likely due to additional phonon modes being available for heat dissipation. These findings offer new insights for optimizing graphene in electronic and photonic technologies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
18 pages, 4 figures
Limitations of the $g$-tensor formalism of semiconductor spin qubits
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
Zoltán György, András Pályi, Gábor Széchenyi
The $ g$ -tensor formalism is a powerful method for describing the electrical driving of semiconductor spin qubits. However, up to now, this technique has only been applied to the simplest qubit dynamics, resonant monochromatic driving by a single gate. Here we study the description of (i) monochromatic driving using two driving gates and bichromatic driving via (ii) one or (iii) two gates. Assuming a general Hamiltonian with qubit states well separated from excited orbital states, we find that when (i) two driving gates are used for monochromatic driving or (ii) a single one for bichromatic, the $ g$ -tensor formalism successfully captures the leading-order dynamics. We express the Rabi frequency and the Bloch-Siegert shift using the $ g$ -tensor and its first and second derivatives with respect to the gate voltage. However, when (iii) bichromatic driving is realized using two distinct driving gates, we see a breakdown of $ g$ -tensor formalism: the Rabi frequency cannot be expressed using the $ g$ -tensor and its derivatives. We find that beyond the $ g$ -tensor and its derivatives, three additional parameters are needed to capture the dynamics. We demonstrate our general results by assuming an electron (hole) confined in a circular quantum dot, subjected to Rashba spin-orbit interaction.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
20 pages, 4 figures
Dispersion-corrected Machine Learning Potentials for 2D van der Waals Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Mikkel Ohm Sauer, Peder Meisner Lyngby, Kristian Sommer Thygesen
Machine-learned interatomic potentials (MLIPs) based on message passing neural networks hold promise to enable large-scale atomistic simulations of complex materials with ab initio accuracy. A number of MLIPs trained on energies and forces from density functional theory (DFT) calculations employing semi-local exchange-correlation (xc) functionals have recently been introduced. Here, we benchmark the performance of six dispersion-corrected MLIPs on a dataset of van der Waals heterobilayers containing between 4 and 300 atoms in the moiré cell. Using various structure similarity metrics, we compare the relaxed heterostructures to the ground truth DFT results. With some notable exceptions, the model precisions are comparable to the uncertainty on the DFT results stemming from the choice of xc-functional. We further explore how the structural inaccuracies propagate to the electronic properties, and find excellent performance with average errors on band energies as low as 35 meV. Our results demonstrate that recent MLIPs after dispersion corrections are on par with DFT for general vdW heterostructures, and thus justify their application to complex and experimentally relevant 2D materials.
Materials Science (cond-mat.mtrl-sci)
11 pages, 8 figures
Magnetic Memory Driven by Orbital Current
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Jingkai Xu, Dongxing Zheng, Meng Tang, Bin He, Man Yang, Hao Li, Yan Li, Aitian Chen, Senfu Zhang, Ziqiang Qiu, Xixiang Zhang
Spin-orbitronics, based on both spin and orbital angular momentum, presents a promising pathway for energy-efficient memory and logic devices. Recent studies have demonstrated the emergence of orbital currents in light transition metals such as Ti, Cr, and Zr, broadening the scope of spin-orbit torque (SOT). In particular, the orbital Hall effect, which arises independently of spin-obit coupling, has shown potential for enhancing torque efficiency in spintronic devices. However, the direct integration of orbital current into magnetic random-access memory (MRAM) remains unexplored. In this work, we design a light metal/heavy metal/ferromagnet multilayer structure and experimentally demonstrate magnetization switching by orbital current. Furthermore, we have realized a robust SOT-MRAM cell by incorporating a reference layer that is pinned by a synthetic antiferromagnetic structure. We observed a tunnel magnetoresistance of 66%, evident in both magnetic field and current-driven switching processes. Our findings underscore the potential for employing orbital current in designing next-generation spintronic devices.
Materials Science (cond-mat.mtrl-sci)
Space-averaged non-equilibrium Green’s function approach for quantum transport in 3D
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
Vahid Mosallanejad, Kuei-Lin Chiu, Wenjie Dou
The non-equilibrium Green’s function (NEGF) approach offers a practical framework for simulating various phenomena in mesoscopic systems. As the dimension of electronic devices shrinks to just a few nanometers, the need for new effective-mass based 3D implementations of NEGF has become increasingly apparent. This work extends our previous Finite-Volume implementation – originally developed for the self-consistent solution of the Schrödinger and Poisson equations in 2D – into a full 3D NEGF framework. Our implementation begins with exploring a few problems with the common textbook Finite Difference implementations of NEGF. We then concisely demonstrate how Finite-Volume discretization addresses few key implementation challenges. Importantly, we explain how this type of discretization enables evaluating the self-energies, which account for the effects of reservoirs. The potential applications of this new method are illustrated through two examples. We anticipate that this implementation will be broadly applicable to open quantum systems, especially in cases where a fully three-dimensional domain is essential.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 4 figures
X-ray Strain and Stress Tensor Tomography
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Peter Modregger, James. A.D. Ball, Felix Wittwer, Ahmar Khaliq, Jonathan Wright
The microscopic distribution of strain and stress plays a crucial role for the performance, safety, and lifetime of components in aeronautics, automotive and critical infrastructure [1]. While non-destructive methods for measuring the stress close to the surface have long been long established, only a limited number of approaches for depth-resolved measurements based on x-rays or neutrons are available [2]. These feature significant limitations, including long scan times, intricate experimental set-ups, limited spatial resolution or anisotropic gauge volumes with aspect ratios of 1:10 or worse. Here, we present a method that overcomes these limitations and obtains tomographic reconstructions of the full six-dimensional strain and stress tensor components. Using a simple and wide spread experimental set-up that combines x-ray powder diffraction with single axis tomography, we achieve non-destructive determination of depth-resolved strain and stress distributions with isotropic resolution. The presented method could be of interest for additive manufacturing of metals [3,4], battery research [5], in-situ metallurgy [6] and the experimental validation of finite element simulations [7].
Materials Science (cond-mat.mtrl-sci), Instrumentation and Detectors (physics.ins-det)
Work statistics and thermal phase transitions
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-09 20:00 EDT
The investigation of nonequilibrium thermodynamics in quantum many-body systems underscores the importance of quantum work, which differs from its classical counterpart due to its statistical nature. Recent studies have shown that quantum work can serve as an effective indicator of quantum phase transitions in systems subjected to sudden quenches. However, the potential of quantum work to identify thermal phase transitions remains largely unexplored. In this paper, we examine several types of thermal phase transitions in a sudden-quench hard-core boson model, including Ising, three-state Potts, and Berezinskii-Kosterlitz-Thouless transitions. Through finite-size scaling analysis, we conclude that work statistics can also characterize the critical behaviors of thermal phase transitions in generic many-body systems. Our investigation paves the way for applying work statistics to characterize critical behavior in many-body systems, with implications that may extend to broader contexts.
Statistical Mechanics (cond-mat.stat-mech)
8 pages, 4 figures
Evanescent Orbital Pumping by Magnetization Dynamics Without Spin-Orbit Coupling
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
Chengyuan Cai, Hanchen Wang, Tao Yu
Converting magnetization spin to orbital current often relies on strong spin-orbit interaction that may cause additional angular momentum dissipation. We report that coherent magnetization dynamics in magnetic nanostructures can evanescently pump an orbital current into adjacent semiconductors due to the Zeeman coupling between its stray magnetic field and electron orbitals without relying on spin-orbit interaction. The underlying photonic spin of the AC magnetic field governs the orbital polarization that flows along the gradient of the driven field. Due to the orbital texture, the orbital Hall current that flows perpendicularly to the gradient of the AC field is also generated and does not suffer from the orbital torque. These findings extend the paradigm of orbital pumping to include photonic spin and pave the way for developing low-dissipation orbitronic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 3 figures
Work probability distribution of weakly driven process in overdamped dynamics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-09 20:00 EDT
Analytical work probability distributions for open classical systems are scarce; they can only be calculated in a few examples. In this work, I present a new method to derive such quantities for weakly driven processes in the overdamped regime for any switching time. The white noise Brownian motion in a harmonic linear stiffening trap illustrates the result. The work probability distribution is non-tabulated, with positive, semi-finite support, diverging at the minimal value, and non-Gaussian. An analysis of the range of validity of linear response is made by using the self-consistent criterion of the fluctuation-dissipation relation. The first, second, third, and fourth moments are correctly calculated for small perturbations.
Statistical Mechanics (cond-mat.stat-mech)
6 pages, 10 figures
Exact results for spin glass criticality
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-09 20:00 EDT
In recent years scale invariant scattering theory provided the first exact access to the magnetic critical properties of two-dimensional statistical systems with quenched disorder. We show how the theory extends to the overlap variables entering the characterization of spin glass properties. The resulting exact fixed point equations yield both the magnetic and, for the first time, the spin glass renormalization group fixed points. For the case of the random bond Ising model, on which we focus, the spin glass subspace of solutions is found to contain a line of fixed points. We discuss the implications of the results for Ising spin glass criticality and compare with the available numerical results.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), High Energy Physics - Theory (hep-th)
Structural and Electrical Transport Properties of NASICON type Na${3}$Zr${2-x}$Ti$_{x}$Si$2$PO${\rm 12}$ ($x=$ 0.1-0.4) Solid Electrolyte Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Ramcharan Meena, Rajendra S. Dhaka
We report the structural, resistivity, impedance, and dielectric studies of isovalent substituted Na$ _{3}$ Zr$ _{2-x}$ Ti$ _{x}$ Si$ _2$ PO$ _{\rm 12}$ ($ x=$ 0.1–0.4) NASICON type solid electrolyte materials. The Rietveld refinement of XRD patterns shows the monoclinic phase with space group of C 2/c for all the samples. The resistivity analysis shows the Arrhenius-type thermal conduction with an increase in activation energy with doping is explained based on decreased unit cell volume. We use Maxwell-Wagner-Sillars (MWS) relaxation and space charge or interfacial polarization models to explain the frequency and temperature-dependent variations of electric permittivity. The double relaxation peaks in the dielectric loss data show the two types of relaxation mechanisms of different activation energy. The real ($ \epsilon^{‘}$ ) and imaginary ($ \epsilon^{‘’}$ ) parts of permittivity are fitted using the modified Cole-Cole equation, including the conductivity term, which show the non-Debye type relaxation over the measured frequency and temperature range. The impedance analysis shows the contributions from grain and grain boundary relaxation. The fitting performed using the impedance and constant-phase element (CPE) confirm the non-Debye type relaxation. Moreover, the electric modulus analysis confirms the ionic nature having thermally activated relaxation and the modulus scaling analysis shows a similar type of relaxation in the measured temperature range. The modified power law is used to understand the frequency dependence of {\it a.c.} conductivity data. The temperature dependence of exponent ($ s$ ) in modified power law suggests the change in the conduction mechanism from near small polaron tunneling (NSPT) to correlated barrier hopping (CBH) above room temperature. The larger values of $ \epsilon$ _{r}$ indicate these materials as a potential candidate for charge-storage devices.
Materials Science (cond-mat.mtrl-sci)
to be published in Small
Gate-tunable hot electron extraction in a two-dimensional semiconductor heterojunction
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
Chenran Xu, Chen Xu, Jichen Zhou, Zhexu Shan, Wenjian Su, Wenbing Li, Xingqi Xu, Kenji Watanabe, Takashi Taniguchi, Shiyao Zhu, Da-Wei Wang, Yanhao Tang
Hot carrier solar cells (HCSCs), harvesting excess energy of the hot carriers generated by above-band-gap photoexcitation, is crucial for pushing the solar cell efficiency beyond the Shockley Queisser limit, which is challenging to realize mainly due to fast hot-carrier cooling. By performing transient reflectance spectroscopy in a MoSe2/hBN/WS2 junction, we demonstrate the gate-tunable harvest of hot electrons from MoSe2 to WS2. By spectrally distinguishing hot-electron extraction from lattice temperature increase, we find that electrostatically doped electrons in MoSe2 can boost hot-electron extraction density (n_ET) by factor up to several tens. Such enhancement arises from interaction between hot excitons and doped electrons, which converts the excess energy of hot excitons to excitations of the Fermi sea and hence generates hot electrons. Moreover, n_ET can be further enhanced by reducing the conduction band offset with external electric field. Our results provide in-depth insights into design of HCSCs with electrostatic strategies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
accepted by Nano Letters
Tunable spin-orbit splitting in bilayer graphene/WSe$_2$ quantum devices
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
Jonas D. Gerber, Efe Ersoy, Michele Masseroni, Markus Niese, Michael Laumer, Artem O. Denisov, Hadrien Duprez, Wei Wister Huang, Christoph Adam, Lara Ostertag, Chuyao Tong, Takashi Taniguchi, Kenji Watanabe, Vladimir I. Fal’ko, Thomas Ihn, Klaus Ensslin, Angelika Knothe
Bilayer graphene (BLG)-based quantum devices represent a promising platform for emerging technologies such as quantum computing and spintronics. However, their intrinsically weak spin-orbit coupling (SOC) presents a challenge for spin and valley manipulation, as these applications operate more efficiently in the presence of strong SOC. Integrating BLG with transition metal dichalcogenides (TMDs) significantly enhances SOC via proximity effects. While this enhancement has been experimentally demonstrated in 2D-layered structures, 1D and 0D-nanostructures in BLG/TMD remain unrealized, with open questions regarding device quality, SOC strength, and tunability. In this work, we investigate quantum point contacts and quantum dots in two BLG/WSe$ 2$ heterostructures with different stacking orders. Across multiple devices, we demonstrate a reproducible enhancement of spin-orbit splitting ($ \Delta\mathrm{SO}$ ) reaching values of up to $ 1.5\mathrm{meV}$ - more than one order of magnitude higher than in pristine bilayer graphene ($ \Delta_\mathrm{SO}=40-80\mu\mathrm{eV}$ ). Furthermore, we show that the induced SOC can be tuned in situ from its maximum value to near-complete suppression by varying the perpendicular electric field, thereby controlling layer polarization. This enhancement and in situ tunability establish SOC as an efficient control mechanism for dynamic spin and valley manipulation.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Multipolar Phase Transition in the 4$f^2$ fcc lattice compound PrCdNi$_{4}$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-09 20:00 EDT
Yuka Kusanose, Yasuyuki Shimura, Kazunori Umeo, Naomi Kawata, Toshiro Takabatake, Taichi Terashima, Naoki Kikugawa, Takako Konoike, Yuya Hattori, Kazuhiro Nawa, Hung-Cheng Wu, Taku J Sato, Takahiro Onimaru
Transport and magnetic properties of a 4$ f^{2}$ fcc lattice compound, PrCdNi$ 4$ , were studied. The magnetic susceptibility, $ \chi(T)$ , follows the Curie–Weiss law from 300 K to 20 K, as expected for a free Pr$ ^{3+}$ ion. As the temperature decreases below 5 K, $ \chi(T)$ approaches a constant, indicating van-Vleck paramagnetic behavior. The specific heat, $ C(T)$ , displays a broad shoulder at around 4 K, which can be reproduced by a doublet triplet two-level model with an energy gap of 12 K. These results suggest a non-magnetic $ \Gamma_3$ doublet ground state of the Pr$ ^{3+}$ ion in the cubic crystalline electric field. $ C(T)$ exhibits a peak at $ T{\rm O}$ = 1.0 K and this peak remains robust against magnetic fields up to 5 T. In powder neutron diffraction measurements, no magnetic reflection was observed at 0.32 K $ <$ $ T_{\rm O}$ . Two anomalies at $ B$ = 2.1 and 5.3 T in magnetoresistance $ \rho(B)$ at 0.05 K likely originate from switching in the order parameter. These results suggest that the phase transition at $ T_{\rm O}$ is ascribed to an antiferro-type order of the electric quadrupole or magnetic octupole of the $ \Gamma_3$ doublet in the 4$ f^2$ fcc lattice.
Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 8 figures. Additional 5 pages, 4 figures 3 tables in supplemental material
Inverse Design of Parameter-Controlled Disclination Paths
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-09 20:00 EDT
Yehonatan Tsubery, Hillel Aharoni
Topological defects, such as disclination lines in nematic liquid crystals, are fundamental to many physical systems and applications. In this work, we study the behavior of nematic disclinations in thin parallel-plate geometries with strong patterned planar anchoring. Building on prior models, we solve both the forward problem – predicting disclination trajectories from given surface patterns – and an extended inverse problem – designing surface patterns to produce a tunable family of disclination curves under varying system parameters. We present an explicit calculation for pattern construction, analyze parameter limitations and stability constraints, and highlight experimental and technological applications.
Soft Condensed Matter (cond-mat.soft)
12 pages, 4 figures, SI 1 page
Learning strategies for optimised fitness in a model of cyclic dominance
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-09 20:00 EDT
A major problem in evolutionary biology is how species learn and adapt under the constraint of environmental conditions and competition of other species. Models of cyclic dominance provide simplified settings in which such questions can be addressed using methods from theoretical physics. We investigate how a privileged (“smart”) species optimises its population by adopting advantageous strategies in one such model. We use a reinforcement learning algorithm, which successfully identifies optimal strategies based on a survival-of-the-weakest effect, including directional incentives to avoid predators. We also characterise the steady-state behaviour of the system in the presence of the smart species and compare with the symmetric case where all species are equivalent.
Statistical Mechanics (cond-mat.stat-mech), Populations and Evolution (q-bio.PE)
22 pages
Comparative Investigation of MAPbBr$x$I${1-x}$ and SbH$_4$Br$x$I${1-x}$ Perovskites: Electronic and Structural Properties
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
This paper comparatively investigates the structural and electronic properties of hybrid perovskites MAPbBr$ _x$ I$ _{1-x}$ and SbH$ _4$ PbBr$ _x$ I$ _{1-x}$ by means of DFT-based calculations. The main aim is to check if the increase in band gap due to substitution of I$ ^-$ ions with Br$ ^-$ ions can be overcome by introducing the inorganic SbH$ _4^+$ cation. Since the Br$ ^-$ ions merely enhance structural stability of the perovskite framework and SbH$ _4^+$ not only sustains that stability but also reduces the band gap to nearly ideal values and thereby improves electronic performance, these are the leading candidates among them. Of them, the reduced band gap SbH$ _4$ PbI$ _3$ ($ \sim$ 1.37 eV) and the perfectly matched SbH$ _4$ PbBrI$ _2$ with its band gap being exactly 1.51 eV are top prospects for being stable and having high-efficiency solar cell applications. The findings show that SbH$ _4^+$ -based perovskites have potential for future photovoltaic devices.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
9 pages, 12 figures
Theory of scanning tunneling spectroscopy beyond one-electron molecular orbitals: can we image molecular orbitals?
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Manish Kumar, Diego Soler, Marco Lozano, Enzo Monino, Libor Veis, Pavel Jelinek
The interpretation of experimental spatially resolved scanning tunneling spectroscopy (STS) maps of close-shell molecules on surfaces is usually interpreted within the framework of oneelectron molecular orbitals. Although this standard practice often gives relatively good agreement with experimental data, it contradicts one of the basic assumptions of quantum mechanics, postulating the impossibility of direct observation of the wavefunction, i.e., individual molecular orbitals. The scanning probe community often considers this contradiction about observing molecular orbitals as a philosophical question rather than a genuine problem. Moreover, in the case of polyradical strongly correlated molecules, the interpretation of STS maps based on one-electron molecular orbitals often fails. Thus, for a precise interpretation of STS maps and their connection to the electronic structure of molecules, a theoretical description, including non-equilibrium tunneling processes going beyond one-electron process, is required. In this contribution, we first show why, in selected cases, it is possible to achieve good agreement with experimental data based on one-electron canonical molecular orbitals and Tersoff-Hamann approximation. Next, we will show that for an accurate interpretation of strongly correlated molecules, it is necessary to describe the process of removing/adding an electron within the formalism of many-electron wavefunctions for the neutral and charged states. This can be accomplished by the concept of so-called Dyson orbitals.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Phonon mediated spin polarization in a one-dimensional Aubry-Andre-Harper chain
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
Moumita Mondal, Santanu K. Maiti
A comparative study of electronic transport and spin polarization between clean and Aubry-Andre-Harper chains in the presence of electron-electron (e-e) and electron-phonon (e-ph) interactions is presented. The entire system is simulated within a tight-binding framework based on the Hubbard-Holstein model. Transmission probability and spin polarization are evaluated using the Green’s function method under the Hartree-Fock mean-field approximation through a self-consistent procedure. The transmission profile is found to be consistent with the band structure, which is also discussed. An overall enhancement of spin polarization induced by e-ph interaction is reported for the first time, to the best of our knowledge. Our analysis may be useful for studying controlled spin-selective electron transmission in the presence of e-ph coupling.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
11 pages, 5 figures [Conference Paper]
Testing the parquet equations and the U(1) Ward identity for real-frequency correlation functions from the multipoint numerical renormalization group
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-09 20:00 EDT
Nepomuk Ritz, Anxiang Ge, Markus Frankenbach, Mathias Pelz, Jan von Delft, Fabian B. Kugler
Recently, it has become possible to compute real-frequency four-point correlation functions of quantum impurity models using a multipoint extension of the numerical renormalization group (mpNRG). In this work, we perform several numerical consistency checks of the output of mpNRG by investigating exact relations between two- and four-point functions. This includes the Bethe-Salpeter equations and the Schwinger-Dyson equation from the parquet formalism, which we evaluate in two formally identical but numerically nonequivalent ways. We also study the first-order U(1) Ward identity between the vertex and the self-energy, which we derive for the first time in full generality in the real-frequency Keldysh formalism. We generally find good agreement of all relations, often up to a few percent, both at weak and at strong interaction.
Strongly Correlated Electrons (cond-mat.str-el)
25 pages, 16 figures, 2 tables
The Interconnection Tensor Rank and the Neural Network Storage Capacity
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-04-09 20:00 EDT
Neural network properties are considered in the case of the interconnection tensor rank being higher than two. This sort of interconnection tensor occurs in realization of crossbar-based neural networks. It is intrinsic for a crossbar design to suffer from parasitic currents. It is shown that the interconnection tensor of a certain form makes the neural network much more efficient: the storage capacity and basin of attraction of the network increase considerably. A network like the Hopfield one is used in the study.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
8 pages, 2 figures
Multi-modal strain mapping of steel crack tips with micrometer spatial resolution
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Ahmar Khaliq, Felix Wittwer, Markus Hartmann, Matthias Thimm, Robert Brandt, Dennis Brueckner, Jan Garrevoet, Gerald Falkenberg, Peter Modregger
Due to their superior fatigue strength, martensitic steels are the material of choice for high cyclic loading applications such as coil springs. However, crack propagation is influenced by residual stresses and their interaction is poorly understood. In fact, Linear Elastic Fracture Mechanics predicts un-physical singularities in the strain around the crack tip. In this study, we have combined synchrotron-based x-ray diffraction, x-ray fluorescence, and optical microscopy to map the factual strain fields around crack tips with micrometer spatial resolution. X-ray fluorescence and optical images were co-registered to locate the crack in the x-ray diffraction maps. Observed crystal recovery close to cracks confirmed that the diffraction signal originates at least in parts from the cracks. The retrieved local strain field around the crack was further improved by averaging information over carefully selected diffraction peaks. This procedure provided strain maps around crack tips with a spatial resolution of about 1 micro meter and enabled a prediction of further crack growth.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Contrasting magnetism in VPS3 and CrI3 monolayers with the common honeycomb S = 3/2 spin lattice
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Ke Yang, Yueyue Ning, Yaozhenghang Ma, Yuxuan Zhou, Hua Wu
Two-dimensional (2D) magnetic materials are promising candidates for spintronics and quantum technologies. One extensively studied example is the ferromagnetic (FM) CrI$ 3$ monolayer with the honeycomb Cr$ ^{3+}$ ($ t{2g}^3$ , $ S$ = 3/2) spin lattice, while VPS$ 3$ has a same honeycomb $ S$ = 3/2 spin lattice (V$ ^{2+}$ , $ t{2g}^3$ ) but displays N$ \acute{e}$ el antiferromagnetism (AFM). In this work, we study the electronic structure and particularly the contrasting magnetism of VPS$ _3$ and CrI$ _3$ monolayers. We find that VPS$ _3$ is a Mott-Hubbard insulator but CrI$ _3$ is a charge-transfer insulator, and therefore their magnetic exchange mechanisms are essentially different. The first nearest-neighbor (1NN) direct $ d$ -$ d$ exchange dominates in VPS$ 3$ , thus leading to a strong antiferromagnetic (AF) coupling. However, the formation of vanadium vacancies, associated with instability of the low-valence V$ ^{2+}$ ions, suppresses the AF coupling and thus strongly reduces the N$ \acute{e}$ el temperature ($ T{\text{N}}$ ) in line with the experimental observation. In contrast, our results reveal that the major 1NN $ d$ -$ p$ -$ d$ superexchanges in CrI$ _3$ via different channels give rise to competing FM and AF couplings, ultimately resulting in a weak FM coupling as observed experimentally. After revisiting several important superexchange channels reported in the literature, based on our MLWFs and tight-binding analyses, we note that some antiphase contributions must be subtly and simultaneously considered, and thus we provide a deeper insight into the FM coupling of CrI$ _3$ . Moreover, we identify and compare the major contributions to the magnetic anisotropy, i.e., a weak shape anisotropy in VPS$ _3$ and a relatively strong exchange anisotropy in CrI$ _3$ .
Materials Science (cond-mat.mtrl-sci)
16 pages, 12 figures, 3 tables
Langevin dynamics with generalized time-reversal symmetry
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-09 20:00 EDT
Dario Lucente, Marco Baldovin, Massimiliano Viale, Angelo Vulpiani
When analyzing the equilibrium properties of a stochastic process, identifying the parity of the variables under time-reversal is imperative. This initial step is required to assess the presence of detailed balance, and to compute the entropy production rate, which is, otherwise, ambiguously defined. In this work we deal with stochastic processes whose underlying time-reversal symmetry cannot be reduced to the usual parity rules (namely, flip of the momentum sign). We provide a systematic method to build equilibrium Langevin dynamics starting from their reversible deterministic counterparts: this strategy can be applied, in particular, to all stable one-dimensional Hamiltonian dynamics, exploiting the time-reversal symmetry unveiled in the action-angle framework. The case of the Lotka-Volterra model is discussed as an example. We also show that other stochastic versions of this system violate time-reversal symmetry and are, therefore, intrinsically out of equilibrium.
Statistical Mechanics (cond-mat.stat-mech)
7 pages, 2 figures + supplemental material
Odd-parity ground state in dilute Yu-Shiba-Rusinov dimers and chains
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
Lisa M. Rütten, Harald Schmid, Werner M. J. van Weerdenburg, Eva Liebhaber, Kai Rossnagel, Katharina J. Franke
Magnetic adatoms on superconductors induce Yu-Shiba-Rusinov (YSR) states, which are key to the design of low-dimensional correlated systems and topological superconductivity. Competing magnetic interactions and superconducting pairing lead to a rich phase diagram. Using a scanning tunneling microscope (STM), we position Fe atoms on 2H-NbSe$ _2$ to build a dimer with an odd-parity ground state, i.e., a partially screened YSR channel with the hybridized states spanning the Fermi level. This ground state makes the dimer a promising precursor for a topological YSR chain. By adding one atom at a time, we track the formation of YSR bands. The lowest-energy band crosses the Fermi level and we find strong site-dependent spectral variations especially at the chain’s terminations. We attribute these features to quantum spin effects and ferromagnetic coupling influenced by the local chemical environment, rather than topological superconductivity or Majorana modes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
3D evolution of protein networks and lipid globules in heat-treated egg yolk
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-09 20:00 EDT
Felix Wittwer, Nimmi Das Anthuparambil, Frederik Unger, Randeer Pratap Gautam, Silja Flenner, Imke Greving, Christian Gutt, Peter Modregger
Upon heating, egg yolk transforms from a liquid to a gel due to protein denaturation. This process can serve as a useful model to better understand protein denaturation in general. Using x-ray holographic tomography, we investigated the structural changes in egg yolk during boiling without the need for complex sample fixation or drying. Our results reveal a developing separation between proteins and lipids, with fatty components rapidly aggregating into large globules that subsequently evolve into bubbles.
Soft Condensed Matter (cond-mat.soft)
Exchange-Biased multi-ring Planar Hall Magnetoresistive Sensors with nT resolution in Non-Shielded Environments
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-09 20:00 EDT
Jan Schmidtpeter, Proloy Taran Das, Yevhen Zabila, Conrad Schubert, Thomas Gundrum, Thomas Wondrak, Denys Makarov
Planar Hall magnetoresistive sensors (PHMR) are promising candidates for various magnetic sensing applications due to their high sensitivity, low power consumption, and compatibility with integrated circuit technology. However, their performance is often limited by inherent noise sources, impacting their resolution and overall sensitivity. Here the effect of three bilayer structures NiFe(10 nm)/IrMn(10 nm), NiFe(30 nm)/IrMn(10 nm), and NiFe(30 nm)/IrMn(20 nm) on noise levels is investigated at low-frequency (DC - 25 Hz). This study includes a detailed investigation on the optimization process and noise characteristics of multiring PHMR sensors, focusing on identifying and quantifying the dominant noise sources. The experimental measurements are complemented by a theoretical analysis of noise sources including thermal noise, 1/f noise, intermixing and environmental noise. The best magnetic resolution is observed for the NiFe(30 nm)/IrMn(10 nm) structure, which achieves a detectivity below 1.5 nT/sqrt(Hz) at 10 Hz in a non-shielded environment at room temperature. In addition, a substantial improvement in sensitivity is observed by annealing the sensors at 250 deg C for 1 hour. The findings of this study contribute to a deeper understanding of noise behavior in PHMR sensors, paving the way for developing strategies to improve their performance for demanding sensing applications at low frequencies.
Strongly Correlated Electrons (cond-mat.str-el), Applied Physics (physics.app-ph)
4 pages, 5 figures
IEEE Magnetics Letters, vol. 15, pp. 1-5, 2024, Art no. 4100205
Characteristic exciton energy scales in antiferromagnetic NiPS$_3$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-09 20:00 EDT
Jacob A. Warshauer, Huyongqing Chen, Qishuo Tan, Jing Tang, Xi Ling, Wanzheng Hu
Two-dimensional antiferromagnets are promising materials for spintronics. The van der Waals antiferromagnet NiPS$ _3$ has attracted extensive interest due to its ultra-narrow exciton feature which is closely linked with the magnetic ordering. Here, we use time-resolved terahertz spectroscopy to investigate photo-excited carriers in NiPS$ _3$ . We identify the onset of interband transitions and estimate the exciton dissociation energy from the excitation wavelength and fluence dependence of the transient spectral weight. Our results provide key insights to quantify the exciton characteristics and validate the band structure for NiPS$ _3$ .
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Physical Review B 111, 155111 (2025)
Fast summation of fermionic Feynman diagrams beyond Bravais Lattices and on-site Hubbard interactions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-09 20:00 EDT
We designed new algorithms for summing bold-line Feynman diagrams in arbitrary channels, where it can be readily modified for bare interaction series as well. When applied to magnetic channel bold-line series with on-site Hubbard interactions, the algorithm achieves competitive performance compared with the state-of-art RPADet. We then generalize it beyond square lattice and on-site Hubbard interactions and achieve better scaling in the number of sites within a unit cell, while there is substantial increase when there are more types of interactions. This work paves the way of diagrammatic Monte Carlo simulations for real materials, holding the premise for a robust replacement of state-of-art simulation tools in the thermodynamical limit.
Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 3 figures. Purely algorithmic constructions for diagrammatic Monte Carlo. More technical backgrounds can be found in arXiv: 2409.02032
Non-reciprocal waves in two-dimensional electron systems with temperature gradient
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
We demonstrate that the interaction of dc temperature gradient with ac magnetic field in temperature-biased two-dimensional electron systems leads to formation of a new electromagnetic mode, a two-dimensional thermomagnetic wave (2d TMW). This wave is transverse electric and non-reciprocal, and its damping rate can be lower than that of conventional 2d plasma waves. The Q-factor of 2d TMW is independent of the wave vector. Numerical estimates show that in state-of-the-art two-dimensional electrons systems the 2d TMW Q-factor is the order of $ 10^{-3}$ . We discuss possible ways to overcome this issue.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
4 page, 1 figure
Timescales for thermalization, quantum chaos, and self-averaging
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-09 20:00 EDT
Isaías Vallejo-Fabila, Lea F. Santos
This chapter discusses the conditions and timescales under which isolated many-body quantum systems, initially far from equilibrium, ultimately reach thermal equilibrium. We also examine quantities that, during the relaxation process, exhibit dynamical manifestations of spectral correlations as in random matrix theory and investigate how these manifestations affect their equilibration times. We refer to systems presenting these spectral correlations as chaotic quantum systems, although the correct term to be employed, whether chaotic or ergodic quantum systems, is debatable and both have limitations.
Statistical Mechanics (cond-mat.stat-mech)
13 pages, 3 figures. Chapter of the Proceedings of the III International Workshop on Quantum Nonstationary Systems (eds. Alexandre Dodonov and Lucas Chibebe Céleri)
Fractional chiral second-order topological insulator from a three-dimensional array of coupled wires
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
Viktoriia Pinchenkova, Katharina Laubscher, Jelena Klinovaja
We construct a model of a three-dimensional chiral second-order topological insulator (SOTI) from an array of weakly coupled nanowires. We show that, in a suitable parameter regime, the interplay between rotating magnetic fields and spatially modulated interwire tunnelings leads to the opening of gaps in the bulk and surface spectrum of the system, while one or more chiral hinge states propagating along a closed path of one-dimensional hinges are left gapless. The exact path of these hinge states is determined by the hierarchy of interwire couplings and the boundary termination of the sample. Depending on the ratio between the period of the rotating magnetic field and the Fermi wavelength, our model can realize both integer and fractional chiral SOTIs. The fractional regime emerges in the presence of strong electron-electron interactions and features hinge states carrying only a fraction $ e/p$ of the electronic charge $ e$ for a positive odd integer $ p$ .
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Interplay between trimer structure and magnetic ground state in Ba5Ru3O12 probed by Neutron and muSR techniques
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-09 20:00 EDT
E. Kushwaha, S. Ghosh, J. Sannigrahi, G. Roy, M. Kumar, S.Cottrell, M. B. Stone, Y. Fang, D. T. Adroja, X. Ke, T. Basu
We report a detailed inelastic neutron scattering (INS) and muon spin relaxation (muSR) investigations of a trimer Ruthenate Ba5Ru3O12 system, which undergoes long-range antiferromagnetic ordering at TN = 60 K. The INS reveals two distinct spin-wave excitations below TN : one around 5.6 meV and the other at 10 to 15 meV. The coexistence of such excitations at both low and high momentum transfer regions is speculated to be strong electronic correlation and spin-phonon coupling of Ruthenium. By accompanying the INS spectra based on a linear spin wave theory using SpinW software, we show that Ba5Ru3O12 exhibits spin frustration due to competing exchange interactions between neighboring and next-neighboring Ru-moments, exchange anisotropy and strong spin-orbit coupling, which yields a non-collinear spin structure, in contrast to other ruthenate trimers in this series. Interestingly, these magnetic excitations does not completely vanish even at high temperatures above TN , evidencing short-range magnetic correlations in this trimer system. This is further supported by muSR spectroscopy, which exhibits a gradual drop in the initial asymmetry around the magnetic phase transition and is further verified through maximum entropy analysis. The results of muSR spectroscopy indicates a dynamic nature of magnetic order, attributed to local magnetic anisotropy within the trimer as a result of local structural distortion and different hybridization, consistent with canted spin-structure. We predict the ground state of Ru3O12-isolated trimer through theoretical calculations which agree with the experimentally observed spin excitation.
Strongly Correlated Electrons (cond-mat.str-el)
Coexistence of magnetic and dielectric glassy states in alternating kagome and triangular lattice LuBaCo$_4$O$_7$ cobaltite
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-09 20:00 EDT
C. Dhanasekhar, D. Chandrasekhar Kakarla, Archana kumari, Monika Jawale, Ronit Hindoddikar, A. Tiwari, Patri Tirupathi, Cang Ting Lai, Mitch M.C. Chou, A. Venimadhav, H. D. Yang, Praveen Chaddah, A. V. Mahajan
To date, the alternating kagome and triangular lattice cobaltites, RBaCo$ _4$ O$ _7$ (R = Ca, Y, and rare earth elements), have been well studied for their large structural distortions, anisotropic exchange interactions, chiral spin liquid states, and giant multiferroic properties. Here, we report the co-existence of magnetic and dielectric glassy states in LuBaCo$ _4$ O$ _7$ below 50 K. AC magnetization studies show an absence of conventional spin-freezing behavior. The cooling and heating in unequal fields (CHUF), thermal cycling, and time-dependent magnetization measurements at low temperature ($ T$ ) show the presence of magnetic glassy state. The $ T$ -dependent dielectric constant $ \epsilon’$ measurements exhibit a strong frequency-independent response at the first-order structural phase transition $ T = 160$ K (trigonal $ P31c$ to monoclinic $ Cc$ ) and also significant features at the $ T = 110$ K (monoclinic $ Cc$ to orthorhombic $ Pbn2_1$ ) phase transition. Further, $ \epsilon’$ shows a frequency-independent peak at 43 K ($ Pbn2_1$ ) and also dipolar glassy features below 20 K ($ Cc$ ). The non-equilibrium magnetic glassy dynamics and dipolar glassy state at low-$ T$ arises from the kinetic arrest of $ Cc$ and $ Pbn2_1$ phases. From the dielectric probe, we are able to clearly distinguish the kinetically arrested phases at low-$ T$ , whereas the bulk magnetization studies are unable to do so as the arrested phases have low magnetic moments.
Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 12 figures
Uniform deposition of particles in large scale by drying of binary droplets
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-09 20:00 EDT
Zechao Jiang, Liyiming Tao, Xiuyuan Yang, Masao Doi, Ye Xu, Xingkun Man
The evaporation of liquid droplets often results in a ring-like deposition pattern of particles, presenting challenges for applications requiring highly uniform patterns. Despite extensive efforts to suppress the coffee ring effect, achieving a uniform particle distribution remains a great challenge due to the complex and non-equilibrium nature of the evaporation process. In this work, we introduce and demonstrate a one-step drying method for binary droplets (water and 2-methoxyethanol) that produces uniform deposition of nano- and micro-particles. By adjusting the initial water volume fraction, we effectively control the interplay between capillary and Marangoni flows, resulting in deposition patterns that vary from coffee ring to uniform and to volcano-like. Through both theoretical and experimental analyses, we determine the conditions necessary for achieving such high uniformity. This approach requires no special substrate treatment, particle modification, or controlled environments, and works for various particles, including silica and polystyrene. Our method provides a robust solution for fabricating uniform patterns that are crucial for many practical applications, ranging from printing to microelectronics to bio-pharmacy.
Soft Condensed Matter (cond-mat.soft)
15pages,5figures
Small, 2501549,1-10 (2025)
Magnetization process in epitaxial Fe${85}$Co${15}$ thin films via anisotropic magnetoresistance
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
L. Saba, J. E. Gómez, D. J. Pérez-Morelo, S. Anguiano, D. Velázquez Rodriguez, A. Butera, M. Granada, L. Avilés-Félix
The effects of the crystalline symmetry on the magnetotransport properties in ferromagnetic alloys are being reexamined in recent years particularly due to the role of the anisotropic magnetoresistance on the electrical detection of magnetization dynamics, which is relevant to estimate spin transport parameters such as the spin Hall angle or the damping constant. In this work we investigated the crystalline dependent anisotropic magnetoresistance in epitaxial Fe85Co15 films and discuss the magnetization process through the magnetotransport properties by varying the relative orientations between the electric current, the external magnetic field and the Fe85Co15 crystallographic directions. We have found that the anisotropic magnetoresistance ratio depends on the current direction with respect to the crystal axes of Fe85Co15 and determine a ratio of 0.20 % and 0.17 % when the current is applied along the [110] hard and [100] easy axes, respectively. We fit our experimental data using the Stoner-Wohlfarth model to describe the path followed by the magnetization during the magnetization process and to extract the anisotropy constants. The fitted cubic and uniaxial anisotropy constants are Kc = 21 kJ/m3 and Ku = 11 kJ/m3, which are comparable with reported values from the angular variation of ferromagnetic resonance experiments. Our results contribute to the understanding of the interplay between the crystalline structure and the magnetotransport properties of FeCo alloys.
Materials Science (cond-mat.mtrl-sci)
Antiferromagnetism and spin excitations in a two-dimensional non-Hermitian Hatano-Nelson flux model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-09 20:00 EDT
Eduard Naichuk, Ilya M. Eremin, Jeroen van den Brink, Flavio S. Nogueira
The one-dimensional Hatano-Nelson model with non-reciprocal hoppings is a prominent example of a relatively simple non-Hermitian quantum-mechanical system, which allows to study various phenomena in open quantum systems without adding extra gain and loss terms. Here we propose to use it as a building block to construct a correlated non-Hermitian Hamiltonian in two dimensions. It has the characteristic form of a flux model with clock-anticlockwise non-reciprocal hopping on each plaquette. Adding the on-site Hubbard type interaction we analyze the formation of the longe-range antiferromagnetic order and its spin excitations. Such a model is non-Hermitian, but $ \mathcal{PT}$ -symmetric, which leads to the existence of two regions: a region of unbroken $ \mathcal{PT}$ symmetry (real-valued spectrum) and a region of broken $ \mathcal{PT}$ symmetry with exceptional lines and complex-valued energy spectrum. The transition from one region to another is controlled by the value of the on-site interaction parameter and coincides with the metal-insulator transition. We also analyze the spin wave spectrum, which is characterized by two diffusive d-wave type of modes corresponding to gain and loss.
Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 5 figures
Quantum-stabilized states in magnetic dipolar quantum gases
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-09 20:00 EDT
A decade ago, a universal stabilization mechanism driven by quantum fluctuations was discovered in ultracold Bose gases of highly magnetic atoms. This mechanism prevents these systems from collapsing and instead allows exotic states of matter to arise, including ultradilute quantum droplets, crystallized quantum states, and specifically supersolids. We review the experimental and theoretical progress in understanding these quantum-stabilized states, their emergence, and intriguing properties.
Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech), Atomic Physics (physics.atom-ph), Quantum Physics (quant-ph)
Radiation-induced Instability of Organic-Inorganic Halide Perovskite Single Crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Ruitian Chen, Mingyu Xie, Tianyi Lyu, Jincong Pang, Lewei Zeng, Jiahui Zhang, Changjun Cheng, Renfei Feng, Guangda Niu, Jiang Tang, Yu Zou
Organic-inorganic halide perovskites (OIHPs) are promising optoelectronic materials, but their instability under radiation environments restricts their durability and practical applications. Here we employ electron and synchrotron X-ray beams, individually, to investigate the radiation-induced instability of two types of OIHP single crystals (FAPbBr3 and MAPbBr3). Under the electron beam, we observe that 3-point star-style cracks grow on the surface of FAPbBr3, and bricklayer-style cracks are formed on the surface of MAPbBr3. Under the X-ray beam, a new composition without organic components appears in both FAPbBr3 and MAPbBr3. Such cracking and composition changes are attributed to the volatilization of organic components. We propose a volume-strain-based mechanism, in which the energy conversion results from the organic cation loss. Using nanoindentation, we reveal that beam radiations reduce the Youngs modulus and increase the hardness of both OIHPs. This study provides valuable insights into the structural and mechanical stabilities of OIHP single crystals in radiation environments.
Materials Science (cond-mat.mtrl-sci)
Signatures of Candidate States of $ν=12/5$ in Shot Noise
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
Fractional quantum Hall (FQH) states are highly sought after because of their ability to host non-abelian anyons, whose braiding statistics make them excellent candidates for qubits in topological quantum computing. Multiple theoretical studies on the $ \nu=\frac{12}{5}$ FQH state predict various quasi-particle states hosted by the $ \frac{12}{5}$ plateau, which include $ \mathbb Z_3$ parafermions and Majorana modes. In this work, we provide a systematic protocol to distinguish among four possible candidate wavefunctions of the $ \frac{12}{5}$ plateau using zero-frequency short noise experiments on a filter-geometry. Qualitative comparisons of Fano-Factors provide a robust way to predict the candidate state across both the full and partial thermal equilibration regimes without prior knowledge of the experimental information, like thermal equilibration length, to allow for more realistic experiments.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
2 figures, 1 table, 8 pages
Orb-v3: atomistic simulation at scale
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Benjamin Rhodes, Sander Vandenhaute, Vaidotas Šimkus, James Gin, Jonathan Godwin, Tim Duignan, Mark Neumann
We introduce Orb-v3, the next generation of the Orb family of universal interatomic potentials. Models in this family expand the performance-speed-memory Pareto frontier, offering near SoTA performance across a range of evaluations with a >10x reduction in latency and > 8x reduction in memory. Our experiments systematically traverse this frontier, charting the trade-off induced by roto-equivariance, conservatism and graph sparsity. Contrary to recent literature, we find that non-equivariant, non-conservative architectures can accurately model physical properties, including those which require higher-order derivatives of the potential energy surface.
This model release is guided by the principle that the most valuable foundation models for atomic simulation will excel on all fronts: accuracy, latency and system size scalability. The reward for doing so is a new era of computational chemistry driven by high-throughput and mesoscale all-atom simulations.
Materials Science (cond-mat.mtrl-sci)
21 pages
The distinction between Ice phases VII, VIII and X
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-09 20:00 EDT
Graeme J Ackland, Andreas Hermann, Kazuki Komatsu, Keishiro Yamashita, J.S. Loveday
Ice phases VII, VIII and X are all based on a body-centered cubic arrangement of molecules, the differences coming from molecular orientation. There is some debate as to whether these should even be considered distinct phases. The standard definition of a transition between distinct phases involves a discontinuity in any derivative of the free energy. This can be hard to prove experimentally, and most previous theoretical works have been based on models which either have continuously differentiable free energies, or no straightforward way to determine the free energy. Here we build a free energy model based on the common definitions of the phases ; ordered ice-VIII, orientationally disordered ice VII and proton-disordered ice X. All transitions in this model might or might not be associated with a discontinuity in the specific heat, depending on paramaterization. By comparing with data, we find that a VII-X transition line exists, but it ends in a critical point hidden within the stability field of phase VIII. If the model is correct, there is a discontinuity between VII and X, so they are separate phases. We propose that the hidden phase boundary might be demonstrated experimentally by compression of supercooled ice VII.
Statistical Mechanics (cond-mat.stat-mech), Materials Science (cond-mat.mtrl-sci)
Appearance of Multiple Spectral Gaps in Voltage-Biased Josephson Junctions Without Floquet Hybridization
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
Teng Zhang, Tatiana de Picoli, Tyler Lindemann, Jukka I. Väyrynen, Michael J. Manfra
A time-periodic drive enables the engineering of non-equilibrium quantum systems by hybridizing Floquet sidebands. We investigated DC voltage-biased planar Josephson junctions built upon epitaxial Al/InAs heterostructures in which the intrinsic AC Josephson effect is theoretically expected to provide a time-periodic drive leading to Floquet hybridization. Tunneling spectroscopy is performed using probes positioned at the ends of the junction to study the evolution of the local density of states. With applied drive, we observe multiple coherence peaks which are studied as a function of DC voltage bias and in-plane magnetic field. Our analysis suggests that these spectral gaps arise from a direct mesoscopic coupling between the tunneling probe and the superconducting leads rather than from a Floquet-driven gap opening. Our numerical simulations indicate that an increase in the ratio of junction width to coherence length will enhance the contribution of Floquet hybridization. This work lays a foundation for the exploration of Floquet physics utilizing voltage-biased hybrid superconductor-semiconductor Josephson junctions and provides means for distinguishing direct couplings from genuine Floquet effects.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
15 pages, 12 figures
Electronic Structure Guided Inverse Design Using Generative Models
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Shuyi Jia, Panchapakesan Ganesh, Victor Fung
The electronic structure of a material fundamentally determines its underlying physical, and by extension, its functional properties. Consequently, the ability to identify or generate materials with desired electronic properties would enable the design of tailored functional materials. Traditional approaches relying on human intuition or exhaustive computational screening of known materials remain inefficient and resource-prohibitive for this task. Here, we introduce DOSMatGen, the first instance of a machine learning method which generates crystal structures that match a given desired electronic density of states. DOSMatGen is an E(3)-equivariant joint diffusion framework, and utilizes classifier-free guidance to accurately condition the generated materials on the density of states. Our experiments find this approach can successfully yield materials which are both stable and match closely with the desired density of states. Furthermore, this method is highly flexible and allows for finely controlled generation which can target specific templates or even individual sites within a material. This method enables a more physics-driven approach to designing new materials for applications including catalysts, photovoltaics, and superconductors.
Materials Science (cond-mat.mtrl-sci)
Moiré enhanced flat band in rhombohedral graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-09 20:00 EDT
Hongyun Zhang, Jinxi Lu, Kai Liu, Yijie Wang, Fei Wang, Size Wu, Wanying Chen, Xuanxi Cai, Kenji Watanabe, Takashi Taniguchi, Jose Avila, Pavel Dudin, Matthew D. Watson, Alex Louat, Takafumi Sato, Pu Yu, Wenhui Duan, Zhida Song, Guorui Chen, Shuyun Zhou
The fractional quantum anomalous Hall effect (FQAHE) is a fascinating emergent quantum state characterized by fractionally charged excitations in the absence of magnetic field,which could arise from the intricate interplay between electron correlation, nontrivial topology and spontaneous time-reversal symmetry breaking. Recently, FQAHE has been realized in aligned rhombohedral pentalayer graphene on BN superlattice (aligned R5G/BN), where the topological flat band is modulated by the moiré potential. However, intriguingly, the FQAHE is observed only when electrons are pushed away from the moiré interface. The apparently opposite implications from these experimental observations, along with different theoretical models, have sparked intense debates regarding the role of the moiré potential. Unambiguous experimental observation of the topological flat band as well as moiré bands with energy and momentum resolved information is therefore critical to elucidate the underlying mechanism. Here by performing nanospot angle-resolved photoemission spectroscopy (NanoARPES) measurements, we directly reveal the topological flat band electronic structures of R5G, from which key hopping parameters essential for determining the fundamental electronic structure of rhombohedral graphene are extracted. Moreover, a comparison of electronic structures between aligned and non-aligned samples reveals that the moiré potential plays a pivotal role in enhancing the topological flat band in the aligned sample. Our study provides experimental guiding lines to narrow down the phase space of rhombohedral graphene, laying an important foundation for understanding exotic quantum phenomena in this emerging platform.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
15 pages,4 figures
Two-Dimensional Ferroelectric Altermagnets: From Model to Material Realization
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-09 20:00 EDT
Ziye Zhu, Xunkai Duan, Jiayong Zhang, Bowen Hao, Igor Zutic, Tong Zhou
Multiferroic altermagnets offer new opportunities for magnetoelectric coupling and electrically tunable spintronics. However, due to intrinsic symmetry conflicts between altermagnetism and ferroelectricity, achieving their coexistence, known as ferroelectric altermagnets (FEAM), remains an outstanding challenge, especially in two-dimensional (2D) systems. Here, we propose a universal, symmetry-based design principle for 2D FEAM, supported by tight-binding models and first-principles calculations. We show that ferroelectric lattice distortions can break spin equivalence and introduce the necessary rotational symmetry, enabling altermagnetism with electrically reversible spin splitting. Guided by this framework, we identify a family of 2D vanadium oxyhalides and sulfide halides as promising FEAM candidates. In these compounds, pseudo Jahn-Teller distortions and Peierls-like dimerization cooperatively establish the required symmetry conditions. We further propose the magneto-optical Kerr effect as an experimental probe to confirm FEAM and its electric spin reversal. Our findings provide a practical framework for 2D FEAM and advancing electrically controlled spintronic devices.
Materials Science (cond-mat.mtrl-sci)
6 pages, 4 figures
Paraxial fluids of light
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-09 20:00 EDT
Quentin Glorieux, Clara Piekarski, Quentin Schibler, Tangui Aladjidi, Myrann Baker-Rasooli
Paraxial fluids of light are a promising platform for exploring collective phenomena in a highly tunable environment. These systems, which map the propagation of light through nonlinear media onto the wavefunction of effective 2D quantum fluids, offer a complementary approach to traditional platforms such as cold atomic gases or superfluid helium. In this review, we present a detailed overview of the theoretical framework underlying paraxial fluids of light, including the nonlinear Schrödinger equation (NLSE) and its mapping to the 2D+1 Gross-Pitaevskii equation (GPE). We explore the hydrodynamic formulation of these systems and we provide a comparative analysis of fluids of light and cold atomic gases, examining key parameters and figures of merit.
We then review the recent experimental advances and the experimental platforms currently used to realize paraxial fluids of light, including hot atomic vapors, photorefractive crystals, and thermo-optic media. Additionally, we question the geometry of the system extending the analogy from 2D+1 to lower or higher dimensions.
Looking forward, we outline the potential future directions for the field, including the use of laser cooled atoms as nonlinear media, the study of two-component mixtures, and the exploration of quantum effects beyond the mean-field approximation. These developments promise to deepen our understanding of quantum fluids and potentially contribute to advances in quantum technologies.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
Prethermalization of light and matter in cavity-coupled Rydberg arrays
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-09 20:00 EDT
Aleksandr N. Mikheev, Hossein Hosseinabadi, Jamir Marino
We explore the dynamics of two-dimensional Rydberg atom arrays coupled to a single-mode optical cavity, employing nonequilibrium diagrammatic techniques to capture nonlinearities and fluctuations beyond mean-field theory. We discover a novel prethermalization regime driven by the interplay between short-range Rydberg interactions and long-range photon-mediated interactions. In this regime, matter and light equilibrate at distinct - and in some cases opposite - effective temperatures, resembling the original concept of prethermalization from particle physics. Our results establish strongly correlated AMO platforms as tools to investigate fundamental questions in statistical mechanics, including quantum thermalization in higher-dimensional systems.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
13 pages, 4 figures