CMP Journal 2025-04-30
Statistics
Nature: 23
Nature Nanotechnology: 1
Physical Review Letters: 14
Physical Review X: 1
arXiv: 70
Nature
A DNA-gated molecular guard controls bacterial Hailong anti-phage defence
Original Paper | Bacterial structural biology | 2025-04-29 20:00 EDT
Joel M. J. Tan, Sarah Melamed, Joshua C. Cofsky, Deepsing Syangtan, Samuel J. Hobbs, Josefina Del Marmol, Marco Jost, Andrew C. Kruse, Rotem Sorek, Philip J. Kranzusch
Animal and bacterial cells use nucleotidyltransferase (NTase) enzymes to respond to viral infection and control major forms of immune signaling including cGAS-STING innate immunity and CBASS anti-phage defence1-4. Here we discover a family of bacterial defence systems, which we name Hailong, that use NTase enzymes to constitutively synthesize DNA signals and guard against phage infection. Hailong protein B (HalB) is an NTase that converts deoxy-ATP into single-stranded DNA oligomers. A series of X-ray crystal structures define a stepwise mechanism of HalB DNA synthesis initiated by a C-terminal tyrosine residue that enables de novo enzymatic priming. We show that HalB DNA signals bind to and repress activation of a partnering Hailong protein A (HalA) effector complex. A 2.0 Å cryo-EM structure of the HalA-DNA complex reveals a membrane protein with a conserved ion channel domain and a unique crown domain that binds the DNA signal and gates activation. Analyzing Hailong defence in vivo, we demonstrate that viral DNA exonucleases required for phage replication trigger release of the primed HalA complex and induce protective host cell growth arrest. Our results explain how inhibitory nucleotide immune signals can serve as molecular guards against phage infection and expand the mechanisms NTase enzymes use to control antiviral immunity.
Bacterial structural biology, Phage biology, X-ray crystallography
A MERS-CoV-like mink coronavirus uses ACE2 as entry receptor
Original Paper | Molecular modelling | 2025-04-29 20:00 EDT
Ningning Wang, Weiwei Ji, Houqi Jiao, Michael Veit, Ju Sun, Yanjun Wang, Xing Ma, Yu Wang, Yutong Wang, Xin-xin Li, Xiaoguang Zhang, Jie Chen, Jiayu Wei, Ying Xu, Dawei Guo, Xiaofeng Zhai, Andres Merits, Chang Li, Félix A. Rey, Georgi M. Dobrikov, George F. Gao, Shuijun Zhang, Yuhai Bi, Shuo Su
Despite accumulating evidence that bat-derived coronaviruses often require intermediate hosts to facilitate transmission to humans1, the potential role of fur animals in zoonotic coronavirus spillovers has largely been overlooked2. Here we report the isolation and characterization of a novel mink respiratory coronavirus (MRCoV) from farmed minks with pneumonia. Notably, MRCoV uses angiotensin-converting enzyme 2 (ACE2) as a receptor and can infect mink, bat, monkey, and human cells. Cryo-electron microscopy analysis revealed that the MRCoV receptor-binding domain (RBD) binds to the same interface on ACE2 receptors as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RBD, despite exhibiting notable structural differences. We identify the key determinants on ACE2 and MRCoV RBD that confer efficient binding. HKU5-33S, a bat coronavirus closely related to MRCoV, utilizes ACE2 of bat Pipistrellus abramus and requires only two amino acid substitutions to adapt to mink ACE2. Furthermore, SARS-CoV-2 protease and polymerase inhibitors potently block MRCoV infection, indicating a potential therapeutic strategy. Collectively, these findings enhance the understanding of coronavirus receptor dynamics and highlight their zoonotic potential. Given the risks posed by fur farms as reservoirs for emerging pathogens, our study underscores the urgent need for enhanced surveillance to mitigate future coronavirus outbreaks.
Molecular modelling, Virus-host interactions
Metal-centred planar [15]annulenes
Original Paper | Chemical bonding | 2025-04-29 20:00 EDT
Binbin Xu, Dafa Chen, Kaidong Ruan, Ming Luo, Yuanting Cai, Jia Qiu, Wenhao Zhou, Bula Cao, Zhenyang Lin, Jonathan L. Sessler, Haiping Xia
The discovery of ferrocene1 heralded the advent of modern organometallic chemistry. Characterized by the π-coordination of a metal by one or two planar annulene anions, ferrocenes and their analogues2,3,4 exemplify the archetype of out-of-plane annulene metal complexes. By contrast, the integration of metal within the annulene core to form in-plane annulene metal complexes featuring metal-carbon σ bonds has been obstructed not only by the synthetic difficulty and the non-planarity of annulenes with appropriate internal dimensions, but also by the difficulty of embedding the metal. These challenges have prevented the isolation of such in-plane annulene metal complexes. Here we report the preparation of three metal-centred planar [15]annulene frameworks. The most symmetrical fragment has D5h symmetry, with the metal centre shared by five identical five-membered rings. Density functional theory calculations demonstrate that metal d orbitals participate in conjugation with these five-membered rings, rendering all of them aromatic. The overall framework bears a loose structural and spectroscopic analogy to metallo-expanded porphyrins with multiple aza donors5, which thus provides a nexus between annulene chemistry and classic heteroatom-based coordination chemistry. The present systems display high stability and are easily functionalized. We thus suggest that metal-centred planar annulenes could emerge as promising building blocks for materials science.
Chemical bonding, Ligands
Adversarial testing of global neuronal workspace and integrated information theories of consciousness
Original Paper | Consciousness | 2025-04-29 20:00 EDT
Oscar Ferrante, Urszula Gorska-Klimowska, Simon Henin, Rony Hirschhorn, Aya Khalaf, Alex Lepauvre, Ling Liu, David Richter, Yamil Vidal, Niccolò Bonacchi, Tanya Brown, Praveen Sripad, Marcelo Armendariz, Katarina Bendtz, Tara Ghafari, Dorottya Hetenyi, Jay Jeschke, Csaba Kozma, David R. Mazumder, Stephanie Montenegro, Alia Seedat, Abdelrahman Sharafeldin, Shujun Yang, Sylvain Baillet, David J. Chalmers, Radoslaw M. Cichy, Francis Fallon, Theofanis I. Panagiotaropoulos, Hal Blumenfeld, Floris P. de Lange, Sasha Devore, Ole Jensen, Gabriel Kreiman, Huan Luo, Melanie Boly, Stanislas Dehaene, Christof Koch, Giulio Tononi, Michael Pitts, Liad Mudrik, Lucia Melloni
Different theories explain how subjective experience arises from brain activity1,2. These theories have independently accrued evidence, but have not been directly compared3. Here we present an open science adversarial collaboration directly juxtaposing integrated information theory (IIT)4,5 and global neuronal workspace theory (GNWT)6,7,8,9,10 via a theory-neutral consortium11,12,13. The theory proponents and the consortium developed and preregistered the experimental design, divergent predictions, expected outcomes and interpretation thereof12. Human participants (n = 256) viewed suprathreshold stimuli for variable durations while neural activity was measured with functional magnetic resonance imaging, magnetoencephalography and intracranial electroencephalography. We found information about conscious content in visual, ventrotemporal and inferior frontal cortex, with sustained responses in occipital and lateral temporal cortex reflecting stimulus duration, and content-specific synchronization between frontal and early visual areas. These results align with some predictions of IIT and GNWT, while substantially challenging key tenets of both theories. For IIT, a lack of sustained synchronization within the posterior cortex contradicts the claim that network connectivity specifies consciousness. GNWT is challenged by the general lack of ignition at stimulus offset and limited representation of certain conscious dimensions in the prefrontal cortex. These challenges extend to other theories of consciousness that share some of the predictions tested here14,15,16,17. Beyond challenging the theories, we present an alternative approach to advance cognitive neuroscience through principled, theory-driven, collaborative research and highlight the need for a quantitative framework for systematic theory testing and building.
Consciousness, Databases
Diet outperforms microbial transplant to drive microbiome recovery in mice
Original Paper | Gastrointestinal diseases | 2025-04-29 20:00 EDT
M. S. Kennedy, A. Freiburger, M. Cooper, K. Beilsmith, M. L. St George, M. Kalski, C. Cham, A. Guzzetta, S. C. Ng, F. K. Chan, O. DeLeon, D. Rubin, C. S. Henry, J. Bergelson, E. B. Chang
A high-fat, low-fibre Western-style diet (WD) induces microbiome dysbiosis characterized by reduced taxonomic diversity and metabolic breadth1,2, which in turn increases risk for a wide array of metabolic3,4,5, immune6 and systemic pathologies. Recent work has established that WD can impair microbiome resilience to acute perturbations such as antibiotic treatment7,8, although little is known about the mechanism of impairment and the specific consequences for the host of prolonged post-antibiotic dysbiosis. Here we characterize the trajectory by which the gut microbiome recovers its taxonomic and functional profile after antibiotic treatment in mice on regular chow (RC) or WD, and find that only mice on RC undergo a rapid successional process of recovery. Metabolic modelling indicates that a RC diet promotes the development of syntrophic cross-feeding interactions, whereas in mice on WD, a dominant taxon monopolizes readily available resources without releasing syntrophic byproducts. Intervention experiments reveal that an appropriate dietary resource environment is both necessary and sufficient for rapid and robust microbiome recovery, whereas microbial transplant is neither. Furthermore, prolonged post-antibiotic dysbiosis in mice on WD renders them susceptible to infection by the intestinal pathogen Salmonella enterica serovar Typhimurium. Our data challenge widespread enthusiasm for faecal microbiota transplant (FMT) as a strategy to address dysbiosis, and demonstrate that specific dietary interventions are, at a minimum, an essential prerequisite for effective FMT, and may afford a safer, more natural and less invasive alternative.
Gastrointestinal diseases, Microbial ecology, Microbiome, Nutrition therapy
TIR domains produce histidine-ADPR as an immune signal in bacteria
Original Paper | Bacterial host response | 2025-04-29 20:00 EDT
Dziugas Sabonis, Carmel Avraham, Renee B. Chang, Allen Lu, Ehud Herbst, Arunas Silanskas, Deividas Vilutis, Azita Leavitt, Erez Yirmiya, Hunter C. Toyoda, Audrone Ruksenaite, Mindaugas Zaremba, Ilya Osterman, Gil Amitai, Philip J. Kranzusch, Rotem Sorek, Giedre Tamulaitiene
Toll/interleukin-1 receptor (TIR) domains are central components of pattern recognition immune proteins across all domains of life1,2. In bacteria and plants, TIR-domain proteins recognize pathogen invasion and then produce immune signalling molecules exclusively comprising nucleotide moieties2,3,4,5. Here we show that the TIR-domain protein of the type II Thoeris defence system in bacteria produces a unique signalling molecule comprising the amino acid histidine conjugated to ADP-ribose (His-ADPR). His-ADPR is generated in response to phage infection and activates the cognate Thoeris effector by binding a Macro domain located at the C terminus of the effector protein. By determining the crystal structure of a ligand-bound Macro domain, we describe the structural basis for His-ADPR and its recognition and show its role by biochemical and mutational analyses. Our analyses furthermore reveal a family of phage proteins that bind and sequester His-ADPR signalling molecules, enabling phages to evade TIR-mediated immunity. These data demonstrate diversity in bacterial TIR signalling and reveal a new class of TIR-derived immune signalling molecules that combine nucleotide and amino acid moieties.
Bacterial host response, X-ray crystallography
Cell cycle duration determines oncogenic transformation capacity
Original Paper | Cancer | 2025-04-29 20:00 EDT
Danian Chen, Suying Lu, Katherine Huang, Joel D. Pearson, Marek Pacal, Phillipos Peidis, Sean McCurdy, Tao Yu, Monika Sangwan, Angela Nguyen, Philippe P. Monnier, Daniel Schramek, Liang Zhu, David Santamaria, Mariano Barbacid, Nagako Akeno, Kathryn A. Wikenheiser-Brokamp, Rod Bremner
Oncogenic mutations are widespread in normal human tissues1. Similarly, in murine chimeras, cells carrying an oncogenic lesion contribute normal cells to adult tissues without causing cancer2,3,4. How lineages that escape cancer via normal development differ from the minority that succumb is unclear. Tumours exhibit characteristic cancer hallmarks; we therefore searched for hallmarks that differentiate cancer-prone lineages from resistant lineages. Here we show that total cell cycle duration (Tc) predicts transformation susceptibility across multiple tumour types. Cancer-prone Rb- and p107-deficient retina (Rb is also known as Rb1 and p107 is also known as Rbl1) exhibited defects in apoptosis, senescence, immune surveillance, angiogenesis, DNA repair, polarity and proliferation. Perturbing the SKP2-p27-CDK2/CDK1 axis could block cancer without affecting these hallmarks. Thus, cancer requires more than the presence of its hallmarks. Notably, every tumour-suppressive mutation that we tested increased Tc, and the Tc of the cell of origin of retinoblastoma cells was half that of resistant lineages. Tc also differentiated the cell of origin in Rb-/- pituitary cancer. In lung, loss of Rb and p53 (also known as Trp53) transforms neuroendocrine cells, whereas KrasG12D or BrafV600E mutations transform alveolar type 2 cells5,6,7. The shortest Tc consistently identified the cell of origin, regardless of mutation timing. Thus, relative Tc is a hallmark of initiation that distinguishes cancer-prone from cancer-resistant lineages in several settings, explaining how mutated cells escape transformation without inducing apoptosis, senescence or immune surveillance.
Cancer, Oncogenes
Structurally complex phase engineering enables hydrogen-tolerant Al alloys
Original Paper | Mechanical properties | 2025-04-29 20:00 EDT
Shengyu Jiang, Yuantao Xu, Ruihong Wang, Xinren Chen, Chaoshuai Guan, Yong Peng, Fuzhu Liu, Mingxu Wang, Xu Liu, Shaoyou Zhang, Genqi Tian, Shenbao Jin, Huiyuan Wang, Hiroyuki Toda, Xuejun Jin, Gang Liu, Baptiste Gault, Jun Sun
Hydrogen embrittlement (HE) impairs the durability of aluminium (Al) alloys and hinders their use in a hydrogen economy1,2,3. Intermetallic compound particles in Al alloys can trap hydrogen and mitigate HE4, but these particles usually form in a low number density compared with conventional strengthening nanoprecipitates. Here we report a size-sieved complex precipitation in Sc-added Al-Mg alloys to achieve a high-density dispersion of both fine Al3Sc nanoprecipitates and in situ formed core-shell Al3(Mg, Sc)2/Al3Sc nanophases with high hydrogen-trapping ability. The two-step heat treatment induces heterogeneous nucleation of the Samson-phase Al3(Mg, Sc)2 on the surface of Al3Sc nanoprecipitates that are only above 10 nm in size. The size dependence is associated with Al3Sc nanoprecipitate incoherency, which leads to local segregation of magnesium and triggers the formation of Al3(Mg, Sc)2. The tailored distribution of dual nanoprecipitates in our Al-Mg-Sc alloy provides about a 40% increase in strength and nearly five times improved HE resistance compared with the Sc-free alloy, reaching a record tensile uniform elongation in Al alloys charged with H up to 7 ppmw. We apply this strategy to other Al-Mg-based alloys, such as Al-Mg-Ti-Zr, Al-Mg-Cu-Sc and Al-Mg-Zn-Sc alloys. Our work showcases a possible route to increase hydrogen resistance in high-strength Al alloys and could be readily adapted to large-scale industrial production.
Mechanical properties, Metals and alloys
Picuris Pueblo oral history and genomics reveal continuity in US Southwest
Original Paper | Anthropology | 2025-04-29 20:00 EDT
Thomaz Pinotti, Michael A. Adler, Richard Mermejo, Julie Bitz-Thorsen, Hugh McColl, Gabriele Scorrano, Motahareh Feizabadifarahani, Devlin Gandy, Matthew Boulanger, Charleen Gaunitz, Jesper Stenderup, Abigail Ramsøe, Thorfinn Korneliussen, Fabrice Demeter, Fabrício R. Santos, Lasse Vinner, Martin Sikora, David J. Meltzer, J. Víctor Moreno-Mayar, Craig Quanchello, Eske Willerslev
Indigenous groups often encounter significant challenges when asserting ancestral claims and cultural affiliations based on oral histories, particularly in the USA where such narratives have historically been undervalued. Although ancient DNA offers a tool to complement traditional knowledge and address gaps in oral history, longstanding disregard for Indigenous sovereignty and beliefs has understandably led many Indigenous communities to distrust DNA studies1,2,3,4. Earlier research often focused on repatriation claims5,6,7, whereas more recent work has increasingly moved towards enhancing Tribal histories8,9. Here we present a collaborative study initiated by a federally recognized Native American tribe, the sovereign nation of Picuris Pueblo in the Northern Rio Grande region of New Mexico, USA, to address gaps in traditional knowledge and further their understanding of their population history and ancestry. We generated genomes from 16 ancient Picuris individuals and 13 present-day members of Picuris Pueblo, providing genomic data spanning the last millennium. We show genetic continuity between ancient and present-day Picuris, and more broadly with Ancestral Puebloans from Pueblo Bonito in Chaco Canyon10, 275 km to the west. This suggests a firm spatiotemporal link among these Puebloan populations of the North American Southwest. Furthermore, we see no evidence of population decline before European arrival11,12,13, and no Athabascan ancestry in individuals predating 1500 ce, challenging earlier migration hypotheses14,15,16. This work prioritizes Indigenous control of genetic data and brings together oral tradition, archaeology, ethnography and genetics.
Anthropology, Archaeology, Genomics, Population genetics
Global evolution of inflammatory bowel disease across epidemiologic stages
Original Paper | Crohn’s disease | 2025-04-29 20:00 EDT
Lindsay Hracs, Joseph W. Windsor, Julia Gorospe, Michael Cummings, Stephanie Coward, Michael J. Buie, Joshua Quan, Quinn Goddard, Léa Caplan, Ante Markovinović, Tyler Williamson, Yvonne Abbey, Murdani Abdullah, Maria T. Abreu, Vineet Ahuja, Raja Affendi Raja Ali, Mansour Altuwaijri, Domingo Balderramo, Rupa Banerjee, Eric I. Benchimol, Charles N. Bernstein, Eduard Brunet-Mas, Johan Burisch, Vui Heng Chong, Iris Dotan, Usha Dutta, Sara El Ouali, Angela Forbes, Anders Forss, Richard Gearry, Viet Hang Dao, Juanda Leo Hartono, Ida Hilmi, Phoebe Hodges, Gareth-Rhys Jones, Fabián Juliao-Baños, Jamilya Kaibullayeva, Paul Kelly, Taku Kobayashi, Paulo Gustavo Kotze, Peter L. Lakatos, Charlie W. Lees, Julajak Limsrivilai, Bobby Lo, Edward V. Loftus Jr, Jonas F. Ludvigsson, Joyce W. Y. Mak, YingLei Miao, Ka Kei Ng, Shinji Okabayashi, Ola Olén, Remo Panaccione, Mukesh Sharma Paudel, Abel Botelho Quaresma, David T. Rubin, Marcellus Simadibrata, Yang Sun, Hidekazu Suzuki, Martin Toro, Dan Turner, Beatriz Iade, Shu Chen Wei, Jesus K. Yamamoto-Furusho, Suk-Kyun Yang, Siew C. Ng, Gilaad G. Kaplan
During the twentieth century, inflammatory bowel disease (IBD) was considered a disease of early industrialized regions in North America, Europe and Oceania1. At the turn of the twenty-first century, IBD incidence increased in newly industrialized and emerging regions in Africa, Asia and Latin America, while the prevalence in early industrialized regions continued to grow steadily2,3,4. Changes in the incidence and prevalence denote the evolution of IBD across four epidemiologic stages: stage 1 (emergence), characterized by low incidence and prevalence; stage 2 (acceleration in incidence), marked by rapidly rising incidence and low prevalence; and stage 3 (compounding prevalence), where the incidence decelerates, plateaus or declines while the prevalence steadily increases. A fourth stage (prevalence equilibrium) has been proposed in which the prevalence slope plateaus due to demographic shifts in an ageing IBD population, but it has not yet been evidenced. To date, these stages have remained theoretical, lacking specific numerical indicators to define transition points. Here, using real-world data from 522 population-based studies encompassing 82 global regions and spanning more than a century (1920-2024), we show spatiotemporal transitions across stages 1-3 and model stage 4 progression. Understanding the evolution of IBD across epidemiologic stages enables healthcare systems to better anticipate the future worldwide burden of IBD.
Crohn’s disease, Epidemiology, Ulcerative colitis
The distribution of subsurface microplastics in the ocean
Original Paper | Environmental sciences | 2025-04-29 20:00 EDT
Shiye Zhao, Karin F. Kvale, Lixin Zhu, Erik R. Zettler, Matthias Egger, Tracy J. Mincer, Linda A. Amaral-Zettler, Laurent Lebreton, Helge Niemann, Ryota Nakajima, Martin Thiel, Ryan P. Bos, Luisa Galgani, Aron Stubbins
Marine plastic pollution is a global issue, with microplastics (1 µm-5 mm) dominating the measured plastic count1,2. Although microplastics can be found throughout the oceanic water column3,4, most studies collect microplastics from surface waters (less than about 50-cm depth) using net tows5. Consequently, our understanding of the microplastics distribution across ocean depths is more limited. Here we synthesize depth-profile data from 1,885 stations collected between 2014 and 2024 to provide insights into the distribution and potential transport mechanisms of subsurface (below about 50-cm depth, which is not usually sampled by traditional practices3,6) microplastics throughout the oceanic water column. We find that the abundances of microplastics range from 10-4 to 104 particles per cubic metre. Microplastic size affects their distribution; the abundance of small microplastics (1 µm to 100 µm) decreases gradually with depth, indicating a more even distribution and longer lifespan in the water column compared with larger microplastics (100 µm to 5,000 µm) that tend to concentrate at the stratified layers. Mid-gyre accumulation zones extend into the subsurface ocean but are concentrated in the top 100 m and predominantly consist of larger microplastics. Our analysis suggests that microplastics constitute a measurable fraction of the total particulate organic carbon, increasing from 0.1% at 30 m to 5% at 2,000 m. Although our study establishes a global benchmark, our findings underscore that the lack of standardization creates substantial uncertainties, making it challenging to advance our comprehension of the distribution of microplastics and its impact on the oceanic environment.
Environmental sciences, Ocean sciences
Pacific hotspots reveal a Louisville-Ontong Java Nui tectonic link
Original Paper | Geochemistry | 2025-04-29 20:00 EDT
J. G. Konter, V. A. Finlayson, K. Konrad, M. G. Jackson, A. A. P. Koppers, P. Wessel, S. Beethe, M. Bizimis, A. Alverson, C. Kelley
Volcanic hotspots are thought to form by melting in an upwelling mantle plume head followed by melting of the plume tail. Plate motion then generates an age-progressive volcanic track originating from a large igneous province to a currently active hotspot. The most voluminous large igneous province, the approximately 120-million-year-old Ontong Java Nui Plateau (OJP-Nui) in the mid-Pacific, however, lacks an obvious volcanic track. Although the Louisville hotspot track was originally proposed as a candidate, limited constraints for Pacific absolute plate and plume motion before 80 million years ago (Ma) suggest a mismatch1. Existing Pacific models rely on age-distance data from the continuous Hawai‘i-Emperor and Louisville tracks, but their tracks older than approximately 80 Ma are subducted. Elsewhere on the Pacific Plate, only discontinuous seamount tracks that formed before 80 Ma are documented2,3,4,5,6,7. Currently, models require approximately 1,200 kilometres of latitudinal motion to link the Louisville plume to the OJP-Nui1, but palaeolatitude estimates from about 70 Ma to today remain within error of its present location8,9, suggesting that any substantial Louisville plume motion occurred earlier. Here, through a combination of geochemistry and geochronology9,10,<a data-test=”citation-ref” data-track=”click” data-track-action=”reference anchor” data-track-label=”link” href=”https://www.nature.com/articles/s41586-025-08889-0#ref-CR11“ id=”ref-link-section-d5889241e539_2” title=”Jackson, M. G. et al. Samoan hot spot track on a “hot spot highway”: implications for mantle plumes and a deep Samoan mantle source. Geochem. Geophys. Geosyst. 11, Q12009 (2010).”>11,12,13,14, we demonstrate that Samoa and Rurutu-Arago are the longest-lived Pacific hotspots, traceable to more than 100 Ma before subducting into the Mariana Trench. These tracks better constrain plate rotation between 80 Ma and 100 Ma, allowing us to update Pacific absolute plate motion models and link the Louisville volcanic track to OJP-Nui without requiring major plume motion.
Geochemistry, Geophysics, Tectonics
Regulation of PV interneuron plasticity by neuropeptide-encoding genes
Original Paper | Cellular neuroscience | 2025-04-29 20:00 EDT
Martijn Selten, Clémence Bernard, Diptendu Mukherjee, Fursham Hamid, Alicia Hanusz-Godoy, Fazal Oozeer, Christoph Zimmer, Oscar Marín
Neuronal activity must be regulated in a narrow permissive band for the proper operation of neural networks. Changes in synaptic connectivity and network activity–for example, during learning–might disturb this balance, eliciting compensatory mechanisms to maintain network function1,2,3. In the neocortex, excitatory pyramidal cells and inhibitory interneurons exhibit robust forms of stabilizing plasticity. However, although neuronal plasticity has been thoroughly studied in pyramidal cells4,5,6,7,8, little is known about how interneurons adapt to persistent changes in their activity. Here we describe a critical cellular process through which cortical parvalbumin-expressing (PV+) interneurons adapt to changes in their activity levels. We found that changes in the activity of individual PV+ interneurons drive bidirectional compensatory adjustments of the number and strength of inhibitory synapses received by these cells, specifically from other PV+ interneurons. High-throughput profiling of ribosome-associated mRNA revealed that increasing the activity of a PV+ interneuron leads to upregulation of two genes encoding multiple secreted neuropeptides: Vgf and Scg2. Functional experiments demonstrated that VGF is critically required for the activity-dependent scaling of inhibitory PV+ synapses onto PV+ interneurons. Our findings reveal an instructive role for neuropeptide-encoding genes in regulating synaptic connections among PV+ interneurons in the adult mouse neocortex.
Cellular neuroscience, Synaptic plasticity
Using life cycle assessment to drive innovation for sustainable cool clouds
Original Paper | Environmental impact | 2025-04-29 20:00 EDT
Husam Alissa, Teresa Nick, Ashish Raniwala, Alberto Arribas Herranz, Kali Frost, Ioannis Manousakis, Kari Lio, Brijesh Warrier, Vaidehi Oruganti, T. J. DiCaprio, Kathryn Oseen-Senda, Bharath Ramakrishnan, Naval Gupta, Ricardo Bianchini, Jim Kleewein, Christian Belady, Marcus Fontoura, Julie Sinistore, Mukunth Natarajan, Lauren Johnson, VeeAnder Mealing, Praneet Arshi, Madeline Frieze
Addressing climate change requires accelerating the development of sustainable alternatives to energy- and water-intensive technologies, particularly for rapidly growing infrastructure such as data centres and cloud1. Here we present a life cycle assessment study examining the impacts of advanced cooling technologies on cloud infrastructure, from virtual machines to server architecture, data centre buildings and the grid. Life cycle assessment is important for early-stage design decisions, enhancing sustainability outcomes alongside feasibility and cost analysis2. We discuss constructing a life cycle assessment for a complex cloud ecosystem (including software, chips, servers and data centre buildings), analysing how different advanced cooling technologies interact with this ecosystem and evaluating each technology from a sustainability perspective to provide adoption guidelines. Life cycle assessment quantifies the benefits of advanced cooling methods, such as cold plates and immersion cooling, in reducing greenhouse gas emissions (15-21%), energy demand (15-20%) and blue water consumption (31-52%) in data centres. This comprehensive approach demonstrates the transformative potential of life cycle assessment in driving sustainable innovation across resource-intensive technologies.
Environmental impact
Selective inhibition of stromal mechanosensing suppresses cardiac fibrosis
Original Paper | Biomaterials | 2025-04-29 20:00 EDT
Sangkyun Cho, Siyeon Rhee, Christopher M. Madl, Arianne Caudal, Dilip Thomas, Hyeonyu Kim, Ana Kojic, Hye Sook Shin, Abhay Mahajan, James W. Jahng, Xi Wang, Phung N. Thai, David T. Paik, Mingqiang Wang, McKay Mullen, Natalie M. Baker, Jeremy Leitz, Souhrid Mukherjee, Virginia D. Winn, Y. Joseph Woo, Helen M. Blau, Joseph C. Wu
Matrix-derived biophysical cues are known to regulate the activation of fibroblasts and their subsequent transdifferentiation into myofibroblasts1,2,3,4,5,6, but whether modulation of these signals can suppress fibrosis in intact tissues remains unclear, particularly in the cardiovascular system7,8,9,10. Here we demonstrate across multiple scales that inhibition of matrix mechanosensing in persistently activated cardiac fibroblasts potentiates–in concert with soluble regulators of the TGFβ pathway–a robust transcriptomic, morphological and metabolic shift towards quiescence. By conducting a meta-analysis of public human and mouse single-cell sequencing datasets, we identify the focal-adhesion-associated tyrosine kinase SRC as a fibroblast-enriched mechanosensor that can be targeted selectively in stromal cells to mimic the effects of matrix softening in vivo. Pharmacological inhibition of SRC by saracatinib, coupled with TGFβ suppression, induces synergistic repression of key profibrotic gene programs in fibroblasts, characterized by a marked inhibition of the MRTF-SRF pathway, which is not seen after treatment with either drug alone. Importantly, the dual treatment alleviates contractile dysfunction in fibrotic engineered heart tissues and in a mouse model of heart failure. Our findings point to joint inhibition of SRC-mediated stromal mechanosensing and TGFβ signalling as a potential mechanotherapeutic strategy for treating cardiovascular fibrosis.
Biomaterials, Cardiovascular diseases, Induced pluripotent stem cells, Target identification, Tissue engineering
Serotonin and neurotensin inputs in the vCA1 dictate opposing social valence
Original Paper | Neural circuits | 2025-04-29 20:00 EDT
Julia M. Zorab, Huanhuan Li, Richa Awasthi, Anna Schinasi, Yoonjeong Cho, Thomas O’Loughlin, Xiaoting Wu
The ability to evaluate valence of a social agent based on social experience is essential for an animal’s survival in its social group1. Although hippocampal circuits have been implicated in distinguishing novel and familiar conspecifics2,3,4,5,6,7, it remains unclear how social valence is constructed on the basis of social history and what mechanisms underlie the heightened valence versatility in dynamic relationships. Here we demonstrate that the ventral (v)CA1 integrates serotonin (5-HT) inputs from the dorsal raphe and neurotensin inputs from the paraventricular nucleus of the thalamus (PVT) to determine positive or negative valence of conspecific representations. Specifically, during an appetitive social interaction 5-HT is released into the vCA1 and disinhibits pyramidal neurons through 5-HT1B receptors, whereas neurotensin is released during an aversive social interaction and potentiates vCA1 neurons directly through NTR1s. Optogenetic silencing of dorsal raphe 5-HT and PVT neurotensin inputs into the vCA1 impairs positive and negative social valence, respectively, and excitation flexibly switches valence assignment. These results show how aversive and rewarding social experiences are linked to conspecific identity through converging dorsal raphe 5-HT and PVT neurotensin signals in the vCA1 that instruct opposing valence, and represent a synaptic switch for flexible social valence computation.
Neural circuits, Social behaviour
A battery-free nanofluidic intracellular delivery patch for internal organs
Original Paper | Biomedical engineering | 2025-04-29 20:00 EDT
Dedong Yin, Pan Wang, Yongcun Hao, Wei Yue, Xinran Jiang, Kuanming Yao, Yuqiong Wang, Xinxin Hang, Ao Xiao, Jingkun Zhou, Long Lin, Zhoulyu Rao, Han Wu, Feng Liu, Zaizai Dong, Meng Wu, Chenjie Xu, Jiandong Huang, Honglong Chang, Yubo Fan, Xinge Yu, Cunjiang Yu, Lingqian Chang, Mo Li
The targeted delivery of therapeutics to internal organs to, for example, promote healing or apoptosis holds promise in the treatment of numerous diseases1,2,3,4. Currently, the prevailing delivery modality relies on the circulation; however, this modality has substantial efficiency, safety and/or controllability limitations5,6,7,8,9. Here we report a battery-free, chipless, soft nanofluidic intracellular delivery (NanoFLUID) patch that provides enhanced and customized delivery of payloads in targeted internal organs. The chipless architecture and the flexible nature of thin functional layers facilitate integration with internal organs. The nanopore-microchannel-microelectrode structure enables safe, efficient and precise electroperforation of the cell membrane, which in turn accelerates intracellular payload transport by approximately 105 times compared with conventional diffusion methods while operating under relatively low-amplitude pulses (20 V). Through evaluations of the NanoFLUID patch in multiple in vivo scenarios, including treatment of breast tumours and acute injury in the liver and modelling tumour development, we validated its efficiency, safety and controllability for organ-targeted delivery. NanoFLUID-mediated in vivo transfection of a gene library also enabled efficient screening of essential drivers of breast cancer metastasis in the lung and liver. Through this approach, DUS2 was identified as a lung-specific metastasis driver. Thus, NanoFLUID represents an innovative bioelectronic platform for the targeted delivery of payloads to internal organs to treat various diseases and to uncover new insights in biology.
Biomedical engineering, Biotechnology
An asymmetric fission island driven by shell effects in light fragments
Original Paper | Experimental nuclear physics | 2025-04-29 20:00 EDT
P. Morfouace, J. Taieb, A. Chatillon, L. Audouin, G. Blanchon, R. N. Bernard, N. Dubray, N. Pillet, D. Regnier, H. Alvarez-Pol, F. Amjad, P. André, G. Authelet, L. Atar, T. Aumann, J. Benlliure, K. Boretzky, L. Bott, T. Brecelj, C. Caesar, P. Carpentier, E. Casarejos, J. Cederkäll, A. Corsi, D. Cortina-Gil, A. Cvetinović, E. De Filippo, T. Dickel, M. Feijoo, L. M. Fonseca, D. Galaviz, G. García-Jiménez, I. Gasparic, E. I. Geraci, R. Gernhäuser, B. Gnoffo, K. Göbel, A. Graña-González, E. Haettner, A.-L. Hartig, M. Heil, A. Heinz, T. Hensel, M. Holl, C. Hornung, A. Horvat, A. Jedele, D. Jelavic Malenica, T. Jenegger, L. Ji, H. T. Johansson, B. Jonson, B. Jurado, N. Kalantar-Nayestanaki, E. Kazantseva, A. Kelic-Heil, O. A. Kiselev, P. Klenze, R. Knöbel, D. Körper, D. Kostyleva, T. Kröll, N. Kuzminchuk, B. Laurent, I. Lihtar, Yu. A. Litvinov, B. Löher, N. S. Martorana, B. Mauss, S. Murillo Morales, D. Mücher, I. Mukha, E. Nacher, A. Obertelli, E. V. Pagano, V. Panin, J. Park, S. Paschalis, M. Petri, S. Pietri, S. Pirrone, G. Politi, L. Ponnath, A. Revel, H.-B. Rhee, J. L. Rodríguez-Sánchez, L. Rose, D. Rossi, P. Roy, P. Russotto, C. Scheidenberger, H. Scheit, H. Simon, S. Storck-Dutine, A. Stott, Y. L. Sun, C. Sürder, Y. K. Tanaka, R. Taniuchi, O. Tengblad, I. Tisma, H. T. Törnqvist, M. Trimarchi, S. Velardita, J. Vesic, B. Voss, F. Wamers, H. Weick, F. Wienholtz, J. Zhao, M. Zhukov
Nuclear fission leads to the splitting of a nucleus into two fragments1,2. Studying the distribution of the masses and charges of the fragments is essential for establishing the fission mechanisms and refining the theoretical models3,4. It has value for our understanding of r-process nucleosynthesis5,6, in which the fission of nuclei with extreme neutron-to-proton ratios is pivotal for determining astrophysical abundances and understanding the origin of the elements7 and for energy applications8,9. Although the asymmetric distribution of fragments is well understood for actinides (elements in the periodic table with atomic numbers from 89 to 103) based on shell effects10, symmetric fission governs the scission process for lighter elements. However, unexpected asymmetric splits have been observed in neutron-deficient exotic nuclei11, prompting extensive further investigations. Here we present measurements of the charge distributions of fission fragments for 100 exotic fissioning systems, 75 of which have never been measured, and establish a connection between the neutron-deficient sub-lead region and the well-understood actinide region. These new data comprehensively map the asymmetric fission island and provide clear evidence for the role played by the deformed Z = 36 proton shell of the light fragment in the fission of sub-lead nuclei. Our dataset will help constrain the fission models used to estimate the fission properties of nuclei with extreme neutron-to-proton ratios for which experimental data are unavailable.
Experimental nuclear physics, Nuclear astrophysics, Nuclear fusion and fission
Single-cell transcriptomics reveal how root tissues adapt to soil stress
Original Paper | Abiotic | 2025-04-29 20:00 EDT
Mingyuan Zhu, Che-Wei Hsu, Lucas L. Peralta Ogorek, Isaiah W. Taylor, Salvatore La Cavera, Dyoni M. Oliveira, Lokesh Verma, Poonam Mehra, Medhavinee Mijar, Ari Sadanandom, Fernando Perez-Cota, Wout Boerjan, Trevor M. Nolan, Malcolm J. Bennett, Philip N. Benfey, Bipin K. Pandey
Land plants thrive in soils showing vastly different properties and environmental stresses1. Root systems can adapt to contrasting soil conditions and stresses, yet how their responses are programmed at the individual cell scale remains unclear. Using single-cell RNA sequencing and spatial transcriptomic approaches, we showed major expression changes in outer root cell types when comparing the single-cell transcriptomes of rice roots grown in gel versus soil conditions. These tissue-specific transcriptional responses are related to nutrient homeostasis, cell wall integrity and defence in response to heterogeneous soil versus homogeneous gel growth conditions. We also demonstrate how the model soil stress, termed compaction, triggers expression changes in cell wall remodelling and barrier formation in outer and inner root tissues, regulated by abscisic acid released from phloem cells. Our study reveals how root tissues communicate and adapt to contrasting soil conditions at single-cell resolution.
Abiotic, Cell wall, Plant morphogenesis, Transcriptomics
Plant diversity dynamics over space and time in a warming Arctic
Original Paper | Biodiversity | 2025-04-29 20:00 EDT
Mariana García Criado, Isla H. Myers-Smith, Anne D. Bjorkman, Sarah C. Elmendorf, Signe Normand, Peter Aastrup, Rien Aerts, Juha M. Alatalo, Lander Baeten, Robert G. Björk, Mats P. Björkman, Noémie Boulanger-Lapointe, Ethan E. Butler, Elisabeth J. Cooper, J. Hans C. Cornelissen, Gergana N. Daskalova, Belen Fadrique, Bruce C. Forbes, Greg H. R. Henry, Robert D. Hollister, Toke Thomas Høye, Ida Bomholt Dyrholm Jacobsen, Annika K. Jägerbrand, Ingibjörg S. Jónsdóttir, Elina Kaarlejärvi, Olga Khitun, Kari Klanderud, Tiina H. M. Kolari, Simone I. Lang, Nicolas Lecomte, Jonathan Lenoir, Petr Macek, Julie Messier, Anders Michelsen, Ulf Molau, Robert Muscarella, Marie-Louise Nielsen, Matteo Petit Bon, Eric Post, Katrine Raundrup, Riikka Rinnan, Christian Rixen, Ingvild Ryde, Josep M. Serra-Diaz, Gabriela Schaepman-Strub, Niels M. Schmidt, Franziska Schrodt, Sofie Sjögersten, Manuel J. Steinbauer, Lærke Stewart, Beate Strandberg, Anne Tolvanen, Craig E. Tweedie, Mark Vellend
The Arctic is warming four times faster than the global average1 and plant communities are responding through shifts in species abundance, composition and distribution2,3,4. However, the direction and magnitude of local changes in plant diversity in the Arctic have not been quantified. Using a compilation of 42,234 records of 490 vascular plant species from 2,174 plots across the Arctic, here we quantified temporal changes in species richness and composition through repeat surveys between 1981 and 2022. We also identified the geographical, climatic and biotic drivers behind these changes. We found greater species richness at lower latitudes and warmer sites, but no indication that, on average, species richness had changed directionally over time. However, species turnover was widespread, with 59% of plots gaining and/or losing species. Proportions of species gains and losses were greater where temperatures had increased the most. Shrub expansion, particularly of erect shrubs, was associated with greater species losses and decreasing species richness. Despite changes in plant composition, Arctic plant communities did not become more similar to each other, suggesting no biotic homogenization so far. Overall, Arctic plant communities changed in richness and composition in different directions, with temperature and plant-plant interactions emerging as the main drivers of change. Our findings demonstrate how climate and biotic drivers can act in concert to alter plant composition, which could precede future biodiversity changes that are likely to affect ecosystem function, wildlife habitats and the livelihoods of Arctic peoples5,6.
Biodiversity, Climate-change ecology, Macroecology
Sustainable nickel enabled by hydrogen-based reduction
Original Paper | Materials science | 2025-04-29 20:00 EDT
U. Manzoor, L. Mujica Roncery, D. Raabe, I. R. Souza Filho
Nickel is a critical element in the shift to sustainable energy systems, with the demand for nickel projected to exceed 6 million tons annually by 20401,2,3,4, largely driven by the electrification of the transport sector. Primary nickel production uses acids and carbon-based reductants, emitting about 20 tons of carbon dioxide per ton of nickel produced5,6,7. Here we present a method using fossil-free hydrogen-plasma-based reduction to extract nickel from low-grade ore variants known as laterites. We bypass the traditional multistep process and combine calcination, smelting, reduction and refining into a single metallurgical step conducted in one furnace. This approach produces high-grade ferronickel alloys at fast reduction kinetics. Thermodynamic control of the atmosphere of the furnace enables selective nickel reduction, yielding an alloy with minimal impurities (<0.04 wt% silicon, approximately 0.01 wt% phosphorus and <0.09 wt% calcium), eliminating the need for further refining. The proposed method has the potential to be up to about 18% more energy efficient while cutting direct carbon dioxide emissions by up to 84% compared with current practice. Our work thus shows a sustainable approach to help resolve the contradiction between the beneficial use of nickel in sustainable energy technologies and the environmental harm caused by its production.
Materials science, Metals and alloys
Comparative connectomics of Drosophila descending and ascending neurons
Original Paper | Computational neuroscience | 2025-04-29 20:00 EDT
Tomke Stürner, Paul Brooks, Laia Serratosa Capdevila, Billy J. Morris, Alexandre Javier, Siqi Fang, Marina Gkantia, Sebastian Cachero, Isabella R. Beckett, Elizabeth C. Marin, Philipp Schlegel, Andrew S. Champion, Ilina Moitra, Alana Richards, Finja Klemm, Leonie Kugel, Shigehiro Namiki, Han S. J. Cheong, Julie Kovalyak, Emily Tenshaw, Ruchi Parekh, Jasper S. Phelps, Brandon Mark, Sven Dorkenwald, Alexander S. Bates, Arie Matsliah, Szi-chieh Yu, Claire E. McKellar, Amy Sterling, H. Sebastian Seung, Mala Murthy, John C. Tuthill, Wei-Chung Allen Lee, Gwyneth M. Card, Marta Costa, Gregory S. X. E. Jefferis, Katharina Eichler
In most complex nervous systems there is a clear anatomical separation between the nerve cord, which contains most of the final motor outputs necessary for behaviour, and the brain. In insects, the neck connective is both a physical and an information bottleneck connecting the brain and the ventral nerve cord (an analogue of the spinal cord) and comprises diverse populations of descending neurons (DNs), ascending neurons (ANs) and sensory ascending neurons, which are crucial for sensorimotor signalling and control. Here, by integrating three separate electron microscopy (EM) datasets1,2,3,4, we provide a complete connectomic description of the ANs and DNs of the Drosophila female nervous system and compare them with neurons of the male nerve cord. Proofread neuronal reconstructions are matched across hemispheres, datasets and sexes. Crucially, we also match 51% of DN cell types to light-level data5 defining specific driver lines, as well as classifying all ascending populations. We use these results to reveal the anatomical and circuit logic of neck connective neurons. We observe connected chains of DNs and ANs spanning the neck, which may subserve motor sequences. We provide a complete description of sexually dimorphic DN and AN populations, with detailed analyses of selected circuits for reproductive behaviours, including male courtship6 (DNa12; also known as aSP22) and song production7 (AN neurons from hemilineage 08B) and female ovipositor extrusion8 (DNp13). Our work provides EM-level circuit analyses that span the entire central nervous system of an adult animal.
Computational neuroscience, Neural circuits
Observation of edge and bulk states in a three-site Kitaev chain
Original Paper | Condensed-matter physics | 2025-04-29 20:00 EDT
Sebastiaan L. D. ten Haaf, Yining Zhang, Qingzhen Wang, Alberto Bordin, Chun-Xiao Liu, Ivan Kulesh, Vincent P. M. Sietses, Christian G. Prosko, Di Xiao, Candice Thomas, Michael J. Manfra, Michael Wimmer, Srijit Goswami
A chain of quantum dots (QDs) in semiconductor-superconductor hybrid systems can form an artificial Kitaev chain hosting Majorana bound states (MBSs)1,2,3. These zero-energy states are expected to be localized on the edges of the chain4, at the outermost QDs. The remaining QDs, comprising the bulk, are predicted to host an excitation gap that protects the MBSs at the edges from local on-site perturbations. Here we demonstrate this connection between the bulk and edges in a minimal system, by engineering a three-site Kitaev chain in a two-dimensional electron gas. Through direct tunnelling spectroscopy on each site, we show that the appearance of stable zero-bias conductance peaks at the outer QDs is correlated with the presence of an excitation gap in the middle QD. Furthermore, we show that this gap can be controlled by applying a superconducting phase difference between the two hybrid segments and that the MBSs are robust only when the excitation gap is present. We find a close agreement between experiments and the original Kitaev model, thus confirming key predictions for MBSs in a three-site chain.
Condensed-matter physics, Quantum physics, Topological matter
Nature Nanotechnology
Single-layer waveguide displays using achromatic metagratings for full-colour augmented reality
Original Paper | Metamaterials | 2025-04-29 20:00 EDT
Seokil Moon, Seokwoo Kim, Joohoon Kim, Chang-Kun Lee, Junsuk Rho
An ideal waveguide display for augmented reality would feature a single-layer waveguide substrate combined with dispersion-free couplers. While metasurfaces have been explored as a potential solution for waveguide displays, severe limitations–such as low efficiency, poor uniformity and chromatic aberration–remain unresolved. Here we introduce a single-layer waveguide display using achromatic metagratings. The proposed metagratings comprise periodic arrays of rectangular nanostructures, diffracting red, green and blue lights in the same direction. Therefore, they ensure an achromatic propagation angle within the single waveguide substrate maintaining high-quality projected images. As a proof of concept, we demonstrate a full-colour augmented reality waveguide display with a 500-μm-thick single-layer waveguide substrate that substantially reduces the device form factor and weight while enhancing brightness and colour uniformity with a sufficient eyebox. This approach overcomes the limitations of traditional augmented reality near-eye optical designs, which rely on multi-layer grating couplers that require complex fabrication processes and are too heavy for ergonomic head-mounted applications.
Metamaterials, Nanophotonics and plasmonics, Photonic devices, Sub-wavelength optics, Surface patterning
Physical Review Letters
Gibbs-Preserving Operations Requiring Infinite Amount of Quantum Coherence
Research article | Quantum coherence & coherence measures | 2025-04-29 06:00 EDT
Hiroyasu Tajima and Ryuji Takagi
Gibbs-preserving operations have been studied as one of the standard free processes in quantum thermodynamics. Although they admit a simple mathematical structure, their operational significance has been unclear due to the potential hidden cost to implement them using an operationally motivated class of operations, such as thermal operations. Here, we show that this hidden cost can be infinite—we present a family of Gibbs-preserving operations that cannot be implemented by thermal operations aided by any finite amount of quantum coherence. Our result implies that there are uncountably many Gibbs-preserving operations that require unbounded thermodynamic resources to implement, raising a question about employing Gibbs-preserving operations as available thermodynamics processes. This finding is a consequence of the general lower bounds we provide for the coherence cost of approximately implementing a certain class of Gibbs-preserving operations with a desired accuracy. We find that our lower bound is almost tight, identifying a quantity—related to the energy change caused by the channel to implement—as a fundamental quantifier characterizing the coherence cost for the approximate implementation of Gibbs-preserving operations.
Phys. Rev. Lett. 134, 170201 (2025)
Quantum coherence & coherence measures, Quantum thermodynamics, Resource theories
Analytic Solution for the Motion of Spinning Particles in Kerr Spacetime
Research article | Classical black holes | 2025-04-29 06:00 EDT
Viktor Skoupý and Vojtěch Witzany
The equations of motion of massive test particles near Kerr black holes are separable in Boyer-Lindquist coordinates, as established by Carter. This separability, however, is lost when the particles are endowed with classical spin. We show that separability of the equations of motion can be recovered to linear order in spin by a shift of the worldline derived with the use of the hidden symmetry of Kerr spacetime. Consequently, the closed-form solution of the motion is expressed in a way closely analogous to the solution for spinless particles. This finding enriches the understanding of separability and integrability properties of the dynamics of test particles and fields in Kerr spacetime and is particularly valuable for modeling inspirals of rotating compact objects into massive black holes.
Phys. Rev. Lett. 134, 171401 (2025)
Classical black holes, Gravitational wave sources, Astronomical black holes, Binary stars
Precision Evaluation of the $\eta $- and ${\eta }^{‘ }$-Pole Contributions to Hadronic Light-by-Light Scattering in the Anomalous Magnetic Moment of the Muon
Research article | Form factors | 2025-04-29 06:00 EDT
Simon Holz, Martin Hoferichter, Bai-Long Hoid, and Bastian Kubis
Next to the ${\pi }^{0}$ pole, $\eta $ and ${\eta }^{‘ }$ intermediate states give rise to the leading singularities of the hadronic light-by-light tensor, resulting in sizable contributions to the anomalous magnetic moment of the muon ${a}{\mu }$. The strength of the poles is determined by the respective transition form factors (TFFs) to two (virtual) photons. We present a calculation of these TFFs that implements a number of low- and high-energy constraints, including the ${\eta }^{(‘ )}\rightarrow \gamma \gamma $ decay widths, ${\eta }^{(‘ )}\rightarrow {\pi }^{+}{\pi }^{- }\gamma $ spectra, chiral symmetry for the ${\eta }^{(‘ )}\rightarrow 2({\pi }^{+}{\pi }^{- })$ amplitudes, vector-meson couplings, and asymptotic limits. Crucially, we investigate the role of the leading left-hand singularity generated by the exchange of the ${a}{2}$ tensor meson, yielding, for the first time, an estimate of the associated factorization-breaking corrections. Our final results, ${a}{\mu }^{\eta \text{ }\mathrm{pole}}=14.7(9)\times{}{10}^{- 11}$ and ${a}{\mu }^{ {\eta }^{‘ }\text{ }\mathrm{pole}}=13.5(7)\times{}{10}^{- 11}$, conclude a dedicated effort to evaluate the pseudoscalar-pole contributions to hadronic light-by-light scattering using dispersion relations, amounting to a combined ${a}{\mu }^{\text{PS poles}}={91.2}{- 2.4}^{+2.9}\times{}{10}^{- 11}$.
Phys. Rev. Lett. 134, 171902 (2025)
Form factors, Light mesons, Muons, Chiral symmetry, Magnetic moment, Real & complex analysis
Berry Curvature and Spin-One Color Superconductivity
Research article | Berry curvature | 2025-04-29 06:00 EDT
Noriyuki Sogabe and Yi Yin
We explore the interplay between Berry curvature and topological properties in single-flavor color superconductors, where quarks form spin-one Cooper pairs. By deriving a new relation, we connect the topological nodal structure of the gap function in momentum space to the (non-Abelian) Berry flux associated with paired quarks. This generalizes the early work by Li and Haldane [Phys. Rev. Lett. 120, 067003 (2018)] to systems with additional internal quantum numbers, such as color. In the ultrarelativistic limit, we uncover rich topological structures driven by the interplay of spin, chirality, and color. Specifically, we identify chirality-induced topological nodes in the transverse (opposite chirality pairing) polar and $A$ phases. In contrast, the color-spin-locking phase lacks these nodes due to a nontrivial color Berry flux, which in turn induces gapless excitations with total Berry monopole charges of $\pm{}3/2$—differing from conventional Weyl fermions. Our findings can be potentially extended to other fermionic systems carrying additional internal degrees of freedom.
Phys. Rev. Lett. 134, 171903 (2025)
Berry curvature, Quantum chromodynamics, Superconductivity
Heavy-Flavor Angular Correlations as a Direct Probe of the Glasma
Research article | Jets & heavy flavor physics | 2025-04-29 06:00 EDT
Dana Avramescu, Vincenzo Greco, Tuomas Lappi, Heikki Mäntysaari, and David Müller
We use classical equations of motion for heavy quarks to show that the preequilibrium glasma phase of a heavy ion collision has an extremely strong effect on heavy quark angular correlations. At the same time the effect on the single inclusive spectrum is much more moderate. This suggests that $D\overline{D}$ meson angular correlations in future LHC measurements could provide a direct experimental access to the physics of the preequilibrium stage.
Phys. Rev. Lett. 134, 172301 (2025)
Jets & heavy flavor physics, Non-Abelian gauge theories, Quark & gluon jets, Relativistic heavy-ion collisions, Strong interaction, Lattice gauge theory
Effects of Retardation on Many-Body Superradiance in Chiral Waveguide QED
Research article | Collective effects in quantum optics | 2025-04-29 06:00 EDT
Bennet Windt, Miguel Bello, Daniel Malz, and J. Ignacio Cirac
We study the superradiant decay of a chain of atoms coupled to a chiral waveguide, focusing on the regime of non-negligible photon propagation time. Using an exact master equation description that accounts for delay effects, we obtain evidence to suggest that competition between collective decay and retardation leads to the emergence of an effective maximum number of atoms able to contribute to the superradiant dynamics, resulting in a plateau of the peak emission rate. To develop this analysis further, we investigate the interatomic correlations to find features consistent with the formation of individual superradiant domains. Moreover, we find that retardation can also result in persistent oscillatory atomic dynamics accompanied by a periodic sequence of emission bursts.
Phys. Rev. Lett. 134, 173601 (2025)
Collective effects in quantum optics, Superradiance & subradiance, Waveguides
Decrease of Static Friction Coefficient with Interface Growth from Single to Multiasperity Contact
Research article | Friction | 2025-04-29 06:00 EDT
Liang Peng, Thibault Roch, Daniel Bonn, and Bart Weber
The key parameter for describing frictional strength at the onset of sliding is the static friction coefficient. Yet, how the static friction coefficient emerges at the macroscale from contacting asperities at the microscale is still an open problem. Here, we present friction experiments in which the normal load was varied over more than 3 orders of magnitude, so that a transition from a single asperity contact at low loads to multiasperity contacts at high loads was achieved. We find a remarkable reduction in the friction drop (the ratio of the static friction force to the dynamic friction force) with increasing normal load. Using a simple stick-slip transition model we identify the presence of presliding and subcritical contact points as the cause of smaller static friction coefficient at increased normal loads. Our measurements and model bridge the gap between friction behavior commonly observed in atomic force microscopy experiments at microscopic forces, and industrially relevant multiasperity contact interfaces loaded with macroscopic forces.
Phys. Rev. Lett. 134, 176202 (2025)
Friction, Tribology, Interfaces, Solid-solid interfaces, Atomic force microscopy
Substrate Polarization Alters the Jahn-Teller Effect in a Single Molecule
Research article | Electronic structure | 2025-04-29 06:00 EDT
Moritz Frankerl, Laerte L. Patera, Felix Giselbrecht, Thomas Frederiksen, Jascha Repp, and Andrea Donarini
Charge-state transitions of a single Cu-phthalocyanine molecule adsorbed on an insulating layer of NaCl on Cu(111) are probed by means of alternate charging scanning tunneling microscopy. Real-space imaging of the electronic transitions reveals the Jahn-Teller distortion occurring upon formation of the first and second anionic charge states. The experimental findings are rationalized by a theoretical many-body model that highlights the crucial role played by the substrate. The latter enhances and stabilizes the intrinsic Jahn-Teller distortion of the negatively charged molecule hosting a degenerate pair of single-particle frontier orbitals. Consequently, two excess electrons are found to occupy, in the ground state, the same localized orbital, despite a larger Coulomb repulsion than the one for the competing delocalized electronic configuration. Control over the charging sequence by varying the applied bias voltage is also predicted.
Phys. Rev. Lett. 134, 176203 (2025)
Electronic structure, Electronic transitions, Jahn-Teller effect, Pseudo Jahn-Teller effect, Molecules, Atomic force microscopy, Discrete symmetries in condensed matter, Scanning tunneling microscopy, Second quantization
Unified One-Parameter Scaling Function for Anderson Localization Transitions in Nonreciprocal Non-Hermitian Systems
Research article | Anderson localization | 2025-04-29 06:00 EDT
C. Wang, Wenxue He, X. R. Wang, and Hechen Ren
Using dimensionless conductances as scaling variables, the conventional one-parameter scaling theory of localization fails for nonreciprocal non-Hermitian systems such as the Hatano-Nelson model. Here, we propose a one-parameter scaling function using the participation ratio as the scaling variable. Employing a highly accurate numerical procedure based on exact diagonalization, we demonstrate that this one-parameter scaling function can describe Anderson localization transitions of nonreciprocal non-Hermitian systems in one and two dimensions of symmetry classes AI and A. The critical exponents of correlation lengths depend on symmetries and dimensionality only, a typical feature of universality. Then, we derive a complex-gap equation based on the self-consistent Born approximation to determine the critical disorder at which the point gap closes. The obtained critical disorders perfectly match those given by the one-parameter scaling function. Moreover, we propose a one-parameter $\beta $ function that can describe the critical properties of such Anderson localization transitions. Finally, we show that the one-parameter scaling function is also valid for Anderson localization transitions in reciprocal non-Hermitian systems such as the two-dimensional class ${\mathrm{AII}}^{\dagger{}}$ and can, thus, serve as a unified scaling function for disordered non-Hermitian systems.
Phys. Rev. Lett. 134, 176301 (2025)
Anderson localization, Non-reciprocal propagation, Quantum phase transitions, Non-Hermitian systems, Finite-size scaling, Nonequilibrium Green’s function, Symmetries in condensed matter
Compressible Quantum Liquid with Vanishing Drude Weight
Research article | Chern insulators | 2025-04-29 06:00 EDT
Ahmed Abouelkomsan, Nisarga Paul, Ady Stern, and Liang Fu
We explore the possibility of quantum liquids that are compressible but have vanishing dc conductivity in the absence of disorder. We show that the composite Fermi liquid emerging from strong interaction in a generic Chern band has zero Drude weight, in stark contrast to normal Fermi liquids. Our Letter establishes the absence of Drude weight as the defining property of the composite Fermi liquid phase, which distinguishes it from the Fermi liquid or other types of non-Fermi liquids. Our findings point to a possibly wide class of gapless quantum phases with unexpected transport and optical properties.
Phys. Rev. Lett. 134, 176501 (2025)
Chern insulators, Flat bands, Optical conductivity, Twistronics
Taming Spin Susceptibilities in Frustrated Quantum Magnets: Mean-Field Form and Approximate Nature of the Quantum-to-Classical Correspondence
Research article | Frustrated magnetism | 2025-04-29 06:00 EDT
Benedikt Schneider and Björn Sbierski
In frustrated magnetism, the empirically found quantum-to-classical correspondence (QCC) matches the real-space static susceptibility pattern of a quantum spin-$1/2$ model with its classical counterpart computed at a certain elevated temperature. This puzzling relation was observed via bold line diagrammatic Monte Carlo simulations in dimensions two and three. The matching was within error bars and seemed valid down to the lowest accessible temperatures $T$ about an order of magnitude smaller than the exchange coupling $J$. Here, we employ resummed spin diagrammatic perturbation theory to show analytically that the QCC breaks weakly at fourth order in $J/T$ and provide the approximate mapping between classical and quantum temperatures. Our treatment further reveals that QCC is an indication of the surprising accuracy with which static correlators can be approximated by a simple renormalized mean-field form. We illustrate this for all models discussed in the context of QCC so far, including a recent example of the $S=1$ material ${\mathrm{K}}{2}{\mathrm{Ni}}{2}({\mathrm{SO}}{4}{)}{3}$. The success of the mean-field form is traced back to partial diagrammatic cancellations.
Phys. Rev. Lett. 134, 176502 (2025)
Frustrated magnetism, Resummation methods, Heisenberg model, Mean field theory
Current-Driven Collective Control of Helical Spin Texture in van der Waals Antiferromagnet
Research article | Magnetism | 2025-04-29 06:00 EDT
Kai-Xuan Zhang, Suik Cheon, Hyuncheol Kim, Pyeongjae Park, Yeochan An, Suhan Son, Jingyuan Cui, Jihoon Keum, Joonyoung Choi, Younjung Jo, Hwiin Ju, Jong-Seok Lee, Youjin Lee, Maxim Avdeev, Armin Kleibert, Hyun-Woo Lee, and Je-Geun Park
The demonstration that helical spin arrangements can be manipulated using electric currents holds promise for spin-based electronics.
Phys. Rev. Lett. 134, 176701 (2025)
Magnetism, Spintronics, 2-dimensional systems, Chiral magnets, Van der Waals systems
Long-Range Angular Correlations of Particle Displacements at a Plastic-to-Elastic Transition in Jammed Amorphous Solids
Research article | Jamming | 2025-04-29 06:00 EDT
Yang Fu, Yuliang Jin, Deng Pan, and Itamar Procaccia
Understanding how a fluid turns into an amorphous solid is a fundamental challenge in statistical physics, during which no apparent structural ordering appears. In the athermal limit, the two states are connected by a well-defined jamming transition, near which the solid is marginally stable. A recent mechanical response screening theory proposes an additional transition above jamming, called a plastic-to-elastic transition here, separating anomalous and quasielastic mechanical behavior. Through numerical inflation simulations in two dimensions, we show that the onsets of long-range radial and angular correlations of particle displacements decouple, occurring, respectively, at the jamming and plastic-to-elastic transitions. The latter is characterized by a power-law diverging correlation angle and a power-law spectrum of the displacements along a circle. This work establishes two-step transitions on the mechanical properties during ‘’decompression melting’’ of an athermal overjammed amorphous solid, reminiscent of the two-step structural melting of a crystal in two dimensions. In contradistinction with the latter, the plastic-to-elastic transition exists also in three dimensions.
Phys. Rev. Lett. 134, 178201 (2025)
Jamming, Amorphous materials
Erratum: Measurement of the Cross Sections of ${\mathrm{\Xi }}{c}^{0}$ and ${\mathrm{\Xi }}{c}^{+}$ Baryons and of the Branching-Fraction Ratio $\mathrm{BR}({\mathrm{\Xi }}{c}^{0}\rightarrow {\mathrm{\Xi }}^{- }{e}^{+}{\nu }{e})/\mathrm{BR}({\mathrm{\Xi }}_{c}^{0}\rightarrow {\mathrm{\Xi }}^{- }{\pi }^{+})$ in $pp$ Collisions at $\sqrt{s}=13\text{ }\text{ }\mathrm{TeV}$ [Phys. Rev. Lett. 127, 272001 (2021)]
Correction | | 2025-04-29 06:00 EDT
S. Acharya et al. (ALICE Collaboration)
et al.
Phys. Rev. Lett. 134, 179902 (2025)
Physical Review X
Single-Crystal Diffuse Neutron Scattering Study of the Dipole-Octupole Quantum Spin-Ice Candidate ${\mathrm{Ce}}{2}{\mathrm{Zr}}{2}{\mathrm{O}}_{7}$: No Apparent Octupolar Correlations Above $T=0.05\text{ }\text{ }\mathrm{K}$
Research article | Frustrated magnetism | 2025-04-29 06:00 EDT
E. M. Smith, R. Schäfer, J. Dudemaine, B. Placke, B. Yuan, Z. Morgan, F. Ye, R. Moessner, O. Benton, A. D. Bianchi, and B. D. Gaulin
Magnetic octupolar correlations in Ce2Zr2O7 are less apparent in neutron diffraction signals than previously thought, a key insight for understanding a new family of quantum spin-ice candidate materials.
Phys. Rev. X 15, 021033 (2025)
Frustrated magnetism, Quantum spin liquid, Spin ice, Pyrochlores, Cluster expansion, Neutron scattering
arXiv
Dielectrophoretic response and electro-deformation of soft bioparticles interacting with a metallo-dielectric Janus active particle
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-30 20:00 EDT
Active (self-propelling) particles have emerged as innovative microscale tools in the field of single cell analysis with the advantages of being untethered, remotely controlled, hybrid powered, with sub-cellular precision. This study investigates the dielectrophoretic (DEP) response and electro-mechanical deformation of cell nuclei interacting with active metallo-dielectric Janus Particles (JPs) under an externally applied electric field. An equivalent droplet two-phase model is employed to simulate the bioparticle, coupling the Navier-Stokes equations with the Phase Field Model to capture fluid motion and interface dynamics. Good qualitative agreement is obtained among experimental, analytical, and numerical results. The findings reveal a nonlinear relationship between nucleus deformation and its surface coverage of the JP with respect to the applied voltage. The overall coverage ratio of the JP dielectric hemisphere increases with voltage as the positive DEP force on the dielectric side strengthens, exhibiting maximum at a certain voltage. The strong correlation between nucleus flexibility and JP surface coverage suggests that the JP coverage ratio could serve as a biomechanical marker for nucleus deformability, providing a novel method for in-situ evaluation of nucleus mechanics.
Soft Condensed Matter (cond-mat.soft)
Thermodynamics for an electron gas in a uniform magnetic field in nonextensive statistics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-30 20:00 EDT
Bienvenu Gnim Adewi, Isiaka Aremua, Laure Gouba
This work deals with the physical system governed by a Hamiltonian operator, in two-dimensional space, of spinless charged particles subject to a perpendicular magnetic field B, coupled with a harmonic potential in the context of nonextensive statistical thermodynamics. The thermodynamics of such a quantum gas system is elaborated in the framework of Tsallis statistics by obtaining the q versions of the partition function, magnetization, and susceptibility after performing the Hilhorst integral transformation. The results are discussed in the q $ \mapsto$ 1 limit.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
15 pages, 2 figures
Acoustic topological Jackiw-Rebbi states at symmetry broken interfaces
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Yifei Xia, An Chen, Ting Zhang, Jing Yang, Bin Liang, Johan Christensen, Jianchun Cheng
Topological insulators, a fundamental concept in modern condensed matter physics, support localized states at the interfaces between insulators exhibiting different topological phases, which conventionally rely on explicit symmetry breaking. Here, we propose a mechanism to induce a real-space topological phase transition by spontaneous symmetry breaking, thereby constructing an acoustic metagrating to generate nontrivial Jackiw-Rebbi states characterized by robust imaginary band degeneracy. Our experimental implementation verifies the acoustic delocalized interface state with a constant phase jump, demonstrating enhanced high-directivity topological radiation. We foresee that our findings may spark interest in engineering new acoustic topological devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Learning the Position of Image Vortices from Data
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-30 20:00 EDT
The point vortex model is an idealized model for describing the dynamics of many vortices with numerical efficiency, and has been shown to be powerful in modeling the dynamics of vortices in a superfluid. The model can be extended to describe vortices in fluids with a well defined boundary, as an image vortex can be added to the equations of motion to impose the correct velocity profile at the boundary. The mathematical formulation of the image vortex depends on the boundary in question, and is well known for a wide variety of problems, although the formulation of an image vortex in a fluid with a soft boundary remains under debate, as the boundary condition is ill-posed. Such a boundary is common-place in the dynamics of a vortex in an ultra-cold atomic Bose-Einstein condensate, for example, which is typically trapped in a harmonic potential.
In order to address this problem, the Sparse Identification of Nonlinear Dynamics framework is applied to data from mean-field simulations to extract an approximate point vortex model for a vortex in a circular power law trapping potential. A formulation for the position of an image vortex in such a trap is presented, and the accuracy of this model is evaluated.
Quantum Gases (cond-mat.quant-gas), Mathematical Physics (math-ph)
13 pages, 6 figures
Multiscale modelling of thermally stressed superelastic polyimide
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-30 20:00 EDT
Jerome Samuel S, Puneet Kumar Patra, Md Rushdie Ibne Islam
Many thermo-mechanical processes, such as thermal expansion and stress relaxation, originate at the atomistic scale. We develop a sequential multiscale approach to study thermally stressed superelastic polyimide to explore these effects. The continuum-scale smoothed particle hydrodynamics (SPH) model is coupled with atomistic molecular dynamics (MD) through constitutive modelling, where thermo-mechanical properties and equations of state are derived from MD simulations. The results are verified through benchmark problems of heat transfer. Finally, we analyse the insulating capabilities of superelastic polyimide by simulating the thermal response of an aluminium plate. The result shows a considerable reduction in the thermal stress, strain and temperature field development in the aluminium plate when superelastic polyimide is used as an insulator. The present work demonstrates the effectiveness of the multi-scale method in capturing thermo-mechanical interactions in superelastic polyimide.
Materials Science (cond-mat.mtrl-sci), Computational Engineering, Finance, and Science (cs.CE)
25 pages, 17 figures
Paired Parton Trial States for the Superfluid-Fractional Chern Insulator Transition
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-30 20:00 EDT
We consider a model of hard-core bosons on a lattice, half-filling a Chern band such that the system has a continuous transition between a fractional Chern insulator (FCI) and a superfluid state (SF) depending on the bandwidth to bandspacing ratio. We construct a parton-inspired trial wavefunction ansatz for the ground states that has remarkably high overlap with exact diagonalization in both phases and throughout the phase transition. Our ansatz is stable to adding some bosonic interactions beyond the on-site hard core constraint. We confirm that the transition is well described by a projective translation symmetry-protected multiple parton band gap closure, as has been previously predicted. However, unlike prior work, we find that our wavefunctions require anomalous (BCS-like) parton correlations to describe the phase transition and SF phase accurately.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Gases (cond-mat.quant-gas)
5+8 pages
Multi-Band Exact Diagonalization and an Iteration Approach to Hunt For Fractional Chern Insulators in Rhombohedral Multilayer Graphene
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-30 20:00 EDT
Heqiu Li, B. Andrei Bernevig, Nicolas Regnault
We perform a multi-band exact diagonalization (ED) study of rhombohedral pentalayer graphene twisted on hexagonal boron nitride with a focus on fractional Chern insulators (FCI) in systems with weak moiré gaps, complementing the results of [Yu et al., arXiv:2407.13770]. We consider both the charge-neutrality (CN) and average (AVE) interaction schemes. Saliently and surprisingly, we now find using the particle entanglement spectrum that the FCI at filling factor 1/3 in the CN scheme predicted by single-(Hartree-Fock) band ED is unstable towards a transition to charge density wave once a small fraction of electrons is allowed to occupy the higher bands. Meanwhile, the FCI at filling 2/3 in the AVE scheme remains more robust under similar band mixing until being suppressed when increasing band mixing. To tackle truncation errors that arise from including multiple bands in larger system sizes, we propose an ED iteration method that iteratively optimizes the single-particle basis so that the particles in the ground state should reside mainly in the lowest band. Nevertheless, we find that the FCI gap remains absent after convergence when the mixing with higher bands is considered. These findings highlight the delicate sensitivity of FCIs to multi-band effects and the shortcoming of all of the current models to explain the experimental emergence of such phases.
Strongly Correlated Electrons (cond-mat.str-el)
Easy-plane ferromagnetism in single-crystal ErB$_{2}$ at low temperatures
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-30 20:00 EDT
Christoph Resch, Georg Benka, Andreas Bauer, Christian Pfleiderer
We report a study of single crystals of the hexagonal rare-earth diboride ErB$ {2}$ prepared by means of the self-adjusted flux travelling-solvent floating-zone technique. Measurements of the magnetization, ac susceptibility, specific heat, and electrical resistivity consistently establish ferromagnetic order of the Er$ ^{3+}$ moments below a second-order phase transition at $ T{c} = 14$ ~K and a very strong easy-plane anisotropy. Curie–Weiss fits of the ac susceptibility are characteristic of ferromagnetic coupling within the easy hexagonal basal plane, and antiferromagnetic coupling along $ \langle001\rangle$ . Under magnetic field within the basal plane the magnetization is reminiscent of a soft ferromagnet that is polarized in fields above a few tenth of a Tesla, vanishing hysteresis and negligible in-plane anisotropy. Under field along $ \langle001\rangle$ , typical hard-axis behavior is observed with the magnetization increasing only weakly up to a spin-flip transition at $ \mu_{0}H_{c} = 12$ ~T. The easy-plane anisotropy emerges below a crossover temperature $ T_{x} \approx 50$ ~K , i.e. a broad paramagnetic temperature range above $ T_{c}$ is governed by strongly anisotropic magnetic fluctuations.
Strongly Correlated Electrons (cond-mat.str-el)
Shot-noise in strongly-correlated double quantum spin Hall edges
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Andreas Tsantilas, Trithep Devakul, Julian May-Mann
We consider the effects of interactions on the edges of ``double” quantum spin Hall insulators (DQSHIs), motivated by recent experiments on moiré twisted metal dichalcogenides. Without interactions, a DQSHI can be understood as two identical copies of a conventional quantum spin Hall insulator. If interactions are present and $ s^z$ -spin is conserved, we show that there are two possible phases for the DQSHI edge. First is a weakly-correlated edge which has two pairs of helical modes and is adiabatically equivalent to two conventional quantum spin Hall edges. Second is a strongly-correlated edge with only one pair of helical modes. The strongly-correlated edge also has a gap to single-electrons, but is gapless to pairs of electrons. In a quantum point contact geometry, this single-electron gap leads to a Fano factor of $ 2$ in shot noise measurements, compared to a Fano factor of $ 1$ for a weakly-correlated edge.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Gyrotropic magnetic effect in metallic chiral magnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Nisarga Paul, Takamori Park, Jung Hoon Han, Leon Balents
We study the gyrotropic magnetic effect (GME), the low-frequency limit of optical gyrotropy, in metals and semimetals coupled to chiral spin textures. In these systems, the chiral spin texture which lacks inversion symmetry can imprint itself upon the electronic structure through Hund’s coupling, leading to novel low-frequency optical activity. Using perturbation theory and numerical diagonalization of both relativistic and non-relativistic models of conduction electrons coupled to spin textures, we analyze how the GME manifests in both single-$ q$ and multi-$ q$ textures. Analytical expressions for the rotatory power are derived in terms of universal scaling functions. Estimates based on realistic material parameters reveal an experimentally viable range of values for the rotatory power. The GME arises from the orbital and spin magnetic moments of conduction electrons, with the orbital part closely tied to Berry curvature and playing a significant role in relativistic metals but not so in non-relativistic metals where there is no inherent Berry curvature. The spin contribution to the GME can be significant in non-relativistic metals with a large Fermi energy. Our work establishes the GME as a sensitive probe of magnetic chirality and symmetry breaking in metallic chiral magnets.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 + 10 pages
Terahertz Landau level spectroscopy of Dirac fermions in millimeter-scale twisted bilayer graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Benjamin F. Mead, Spenser Talkington, An-Hsi Chen, Debarghya Mallick, Zhaodong Chu, Xingyue Han, Seong-Jun Yang, Cheol-Joo Kim, Matthew Brahlek, Eugene J. Mele, Liang Wu
Exotic electronic physics including correlated insulating states and fractional Chern insulators have been observed in twisted bilayer graphene in a magnetic field when the Fermi velocity vanishes, however a question remains as to the stability of these states which is controlled by the gap to the first excited state. Free-space terahertz magneto-optics can directly probe the gap to charge excitations which bounds the stability of electronic states, but this measurement has thus-far been inaccessible due to the micron size of twisted bilayer graphene samples, while the wavelength of terahertz light is up to a millimeter. Here we leverage advances in fabrication to create twisted bilayer graphene samples over 5 mm x 5 mm in size with a uniform twist angle and study the magnetic field dependence of the cyclotron resonance by a complex Faraday rotation experiment in p-doped large angle twisted bilayer graphene. These measurements directly probe charge excitations in inter-Landau level transitions and determine the Fermi velocity as a function of twist angle.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
7+2 pages, 4+2 figures
Unconventional magnetization in the multiphase superconductor PdBi2
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-30 20:00 EDT
Wenjun Kuang, Ziyi Jiang, Lewis Powell, Sofiia Komrakova, Andre K. Geim, Irina V. Grigorieva
Unconventional superconductors have specific signatures in their magnetic properties, such as intrinsic magnetization at interfaces and around defects and fractional and multiquanta vortices, with much attention focused on heavy fermion and high-T_c superconductors. Here we report an observation of highly anomalous magnetization in a candidate topological superconductor beta-PdBi2, a layered material where hidden inversion symmetry breaking leads to spin polarization and spin-momentum locking of the electronic bands. We observe strictly linear, non-hysteretic dc magnetization, a transition to sharply reduced ac susceptibility vs the magnetic field H applied parallel to the ab plane, and a strong anisotropy between in-plane and out-of-plane H. Based on our earlier finding of a magnetic-field induced phase transition from s-wave to nodal p-wave superconductivity in the tunnelling spectra of PdBi2, we propose that this unusual behavior can be explained by a transition from a conventional vortex structure in low-H s-wave phase to a domain structure corresponding to spatial phase separation into superconducting (nodal p-wave) and normal domains, identifying new features of magnetization that can arise from the multiplicity of superconducting phases.
Superconductivity (cond-mat.supr-con)
18 pages, 9 figures
Phase-locking in dynamical systems and quantum mechanics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-30 20:00 EDT
Artem Alexandrov, Alexey Glutsyuk, Alexander Gorsky
In this study, we discuss the Prufer transform that connects the dynamical system on the torus and the Hill equation, which is interpreted as either the equation of motion for the parametric oscillator or the Schrodinger equation with periodic potential. The structure of phase-locking domains in the dynamical system on torus is mapped into the band-gap structure of the Hill equation. For the parametric oscillator, we provide the relation between the non-adiabatic Hannay angle and the Poincare rotation number of the corresponding dynamical system. In terms of quantum mechanics, the integer rotation number is connected to the quantization number via the Milne quantization approach and exact WKB. Using recent results concerning the exact WKB approach in quantum mechanics, we discuss the possible non-perturbative effects in the dynamical systems on the torus and for parametric oscillator. The semiclassical WKB is interpreted in the framework of a slow-fast dynamical system. The link between the classification of the coadjoint Virasoro orbits and the Hill equation yields a classification of the phase-locking domains in the parameter space in terms of the classification of Virasoro orbits. Our picture is supported by numerical simulations for the model of the Josephson junction and Mathieu equation.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Dynamical Systems (math.DS), Pattern Formation and Solitons (nlin.PS), Quantum Physics (quant-ph)
Hinge electronic structure of strained half-Heuslers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-30 20:00 EDT
Sanjib Kumar Das, Ion Cosma Fulga, Rakshanda Dhawan, Hem C. Kandpal, Jeroen van den Brink, Jorge I. Facio
Half-Heusler compounds are a class of materials with great potential for the study of distinct electronic states. In this work, we investigate, from first-principles, the possibility of hinge modes in closely related topological phases that are tunable by moderate uni-axial strain. We consider two compounds: LiSbZn and LiBiZn. While LiSbZn has a topologically trivial band structure, the larger spin-orbit coupling of Bi causes a band inversion in LiBiZn. We predict the existence of topologically trivial hinge states in both cases. The hinge modes are affected by both the crystal termination, and the bulk topological phase transitions, albeit indirectly: when present, topological surface modes hybridize with the hinge states and obscure their visibility. Thus, we find that the most visible hinge modes occur when no band inversions are present in the material. Our work highlights the interplay and competition between surface and hinge modes in half-Heuslers, and may help guide the experimental search for robust boundary signatures in these materials
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Texture evolution during the development of turbulence in a trapped atomic superfluid
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-30 20:00 EDT
Michelle A. Moreno-Armijos, Leandro Machado, Arnol D. García-Orozco, Sarah Sab, Amilson R. Fritsch, Vanderlei S. Bagnato
Understanding the temporal evolution of out-of-equilibrium systems, such as turbulent Bose-Einstein condensates, remains a significant challenge. Identifying characteristic timescales is crucial for describing this process, since interactions between excitations drive an energy cascade from large to small scales, influencing the evolution of the distribution and magnitude of density fluctuations in real and momentum space. Motivated by these considerations, we investigate the use of density texture as a potential tool to characterize the temporal evolution of turbulence. Our experiment and simulations demonstrate this approach and include an estimate of the characteristic time for texture relaxation.
Quantum Gases (cond-mat.quant-gas)
Nucleation of dislocations in metals: order parameters, transition state, and kinetic rates
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-30 20:00 EDT
Mattia Perrone, David D. Girardier, Giovanni M. Pavan, Fabio Pietrucci
Dislocations are prominent defects in metals, significantly influencing their mechanical, electronic, thermal, and chemical properties. The emergence of such collective defects is typically characterized by nucleation and amplification phases. However, while their dynamical propagation can be followed in great detail, e.g., via atomistic simulations, accurately characterizing the mechanism, transition state, and kinetic rates of dislocations’ nucleation is still a fundamental challenge. One main problem is that identifying well-suited descriptor(s) (order parameter) for characterizing the nucleation process is non-trivial, and a rigorous approach to assess and rank descriptors in this sense is still missing. In this work, we investigate the nucleation of dislocations in an ideal fcc copper crystal using replicated molecular dynamics (MD) simulations starting from configurations of the lattice close to the limit between the elastic and the plastic phases. Using different types of descriptors (order parameters), we obtain from the atomistic trajectories time-series data that we study via committor analyses and statistical inference methods. Our findings highlight the effect of the order parameter’s choice on the description of the nucleation phenomenon. By applying a recently-demonstrated variational principle to stochastic models built on our data, we estimate the free-energy barriers and kinetic rates for dislocation nucleation. Systematic comparison with the “ground truth” (brute force) nucleation rate then provides us a robust approach for ranking the order parameters based on their accuracy in describing the dislocation nucleation process in this copper crystalline system. This approach is general and useful for probing the transition state and studying nucleation events in a variety of other systems.
Materials Science (cond-mat.mtrl-sci)
Magnons in the strained Heisenberg-Kitaev magnet
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Miguel Letelier, Roberto E. Troncoso, Nicolas Vidal-Silva
The properties of magnons hosted in strained Heisenberg-Kitaev magnets are investigated using numerical and analytical calculations. Considering that deformation fields modulate the coupling parameters, we find a general expression for the weakly strained magnon Hamiltonian that depends on the (symmetric) strain tensor. We numerically tested our results in finite nanoribbon structures. We found that uniaxial deformations make the bulk bands more dispersive while topologically protected in-gap edge modes become nonreciprocal at the boundary of the Brillouin Zone. On the other hand, when applying a twist deformation, the simultaneous modulation of both Heisenberg and Kitaev parameters enables the apparition of flat bands, promoting the presence of non-propagative topologically protected magnonic edge states, whose properties strongly depends on the strain strength. In addition, the characteristic localization of magnon edge modes is preserved, which allows for testing the robustness of the bulk-boundary correspondence under lattice deformations. Our results contribute to a major understanding of Heisenberg-Kitaev magnets and how applying different strains allows for precise control over magnon properties.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Density Functional Tight-Binding Enables Tractable Studies of Quantum Plasmonics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Nikhil S. Chellam, Subhajyoti Chaudhuri, Abhisek Ghosal, Sajal K. Giri, George C. Schatz
Routine investigations of plasmonic phenomena at the quantum level present a formidable computational challenge due to the large system sizes and ultrafast timescales involved. This Feature Article highlights the use of density functional tight-binding (DFTB), particularly its real-time time-dependent formulation (RT-TDDFTB), as a tractable approach to study plasmonic nanostructures from a purely quantum mechanical purview. We begin by outlining the theoretical framework and limitations of DFTB, emphasizing its efficiency in modeling systems with thousands of atoms over picosecond timescales. Applications of RT-TDDFTB are then explored in the context of optical absorption, nonlinear harmonic generation, and plasmon-mediated photocatalysis. We demonstrate how DFTB can reconcile classical and quantum descriptions of plasmonic behavior, capturing key phenomena such as size-dependent plasmon shifts and plasmon coupling in nanoparticle assemblies. Finally, we showcase DFTB’s ability to model hot carrier generation and reaction dynamics in plasmon-driven \ch{H2} dissociation, underscoring its potential to model photocatalytic processes. Collectively, these studies establish DFTB as a powerful, yet computationally efficient tool to probe the emergent physics of materials at the limits of space and time.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Force chain dynamics in a quasi-static granular pile
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-30 20:00 EDT
Benjamin Allen, Nicholas W. Hayman
In nature, granular materials fail in abrupt avalanches, earthquakes, and other hazardous events, and also creep over time. Proposed failure mechanisms for these systems are broadly framed as friction-limited. However, mechanical descriptions of friction in granular system vary, including those that consider the non-linear, heterogeneous dynamics of grain-contact forces. In order to study granular controls on failure and creep, we imaged contact forces between quasi-2D photoelastic discs at 15-minute intervals in experiments over weeks- to one-month-long observation periods. In the experiments, the particles are distributed in a slope below the angle of repose with a concomitant establishment of the force-chain network approximately along the principal static stress directions. The discrete force-chain shifts are initially described by an age-weakening Weibull distribution in frequency over time, with the most common clusters of events $ <$ 1000 minutes apart, but there are long quiescent periods that are not well described by the distribution. The post-settling discrete events accompany a longer term strengthening of the localized stresses. We observe that some events may be related to 2$ ^o$ C temperature change, but associated ground motions measured by a seismometer appear to have no correlation with particle displacements or force-chain changes. The results illustrate that local, grain-scale changes in force-chain networks can occur long after a granular pile reaches a mesoscale apparently stable state, sometimes without obvious external forcings or imposed state changes. Such force-chain dynamics may underlie transitions in natural granular systems between large-scale failures and creep events.
Soft Condensed Matter (cond-mat.soft), Geophysics (physics.geo-ph)
22 pages, 9 figures
Impact of Broken Inversion Symmetry on Molecular States in multi-Weyl fermions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
W.C. Silva, J.E. Sanches, D.S. Rojo, L. Squillante, M. de Souza, M.S. Figueira, I.A. Shelykh, E. Marinho Jr., A.C. Seridonio
We study inversion-symmetry (IS) breaking in impurity dimers coupled to topological multi-Weyl systems in the low-energy dispersion domain. In the IS-preserved multi-Weyl semimetal phase, Hubbard bands split into symmetric and antisymmetric molecular-like subbands. Breaking IS induces a transition to a multi-Weyl metal, lifting the degeneracy of the Weyl node and closing the pseudogap. This causes opposite energy shifts: valence-band symmetric (antisymmetric) subbands red- (blue-) shift, reversing in the conduction band until a degeneracy point. Beyond this threshold, symmetric bands flatten near band cutoffs, whereas antisymmetric bands form quasi-zero energy modes asymptotically approaching -yet never crossing- the Fermi level. Crucially, identical molecular symmetries maintain nondegeneracy even as energy separation vanishes with stronger IS breaking. Our results demonstrate symmetry-selective mechanisms for topological molecular states in multi-Weyl systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
On-chip calibrated radio-frequency measurement at cryogenic temperatures for determination of SrTiO3-based capacitor properties
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Akitomi Shirachi, Motoya Shinozaki, Yasuhide Tomioka, Hisashi Inoue, Kenta Itoh, Yusuke Kozuka, Takanobu Watanabe, Shoichi Sato, Takeshi Kumasaka, Tomohiro Otsuka
Quantum computing has emerged as a promising technology for next-generation information processing, utilizing semiconductor quantum dots as one of the candidates for quantum bits. Radio-frequency (rf) reflectometry plays an important role in the readout of quantum dots but requires a precise rf measurement technique at cryogenic temperatures. While cryogenic calibration techniques, essential for rf reflectometry, have been developed, on-chip calibration near the device remains an important challenge. In this study, we develop an on-chip calibrated rf measurement system operating at 4K for characterizing SrTiO3-based varactors, which are promising components for tunable impedance matching circuits. Our system enables accurate measurements by eliminating errors associated with long rf circuit lines. We investigate the effects of annealing conditions, crystal orientation, and Ca doping of SrTiO3 crystals on the varactor properties in the frequency range for rf reflectometry. Our results provide insights for optimizing these components for cryogenic rf applications in quantum information processing systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 4 figures
Ant Colony Optimization for Density Functionals in Strongly Correlated Systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-30 20:00 EDT
G. M. Tonin, T. Pauletti, R. M. Dos Santos, V. V. França
The Ant Colony Optimization (ACO) algorithm is a nature-inspired metaheuristic method used for optimization problems. Although not a machine learning method per se, ACO is often employed alongside machine learning models to enhance performance through optimization. We adapt an ACO algorithm to optimize the so-called FVC density functional for the ground-state energy of strongly correlated systems. We find the parameter configurations that maximize optimization efficiency, while reducing the mean relative error ($ MRE$ ) of the ACO functional. We then analyze the algorithm’s performance across different dimensionalities ($ 1D-5D$ ), which are related to the number of parameters to be optimized within the FVC functional. Our results indicate that $ 15$ ants with a pheromone evaporation rate superior to $ 0.2$ are sufficient to minimize the $ MRE$ for a vast regime of parameters of the strongly-correlated system – interaction, particle density and spin magnetization. While the optimizations $ 1D$ , $ 2D$ , and $ 4D$ yield $ 1.5%< MRE< 2.7%$ , the $ 3D$ and $ 5D$ optimizations lower the $ MRE$ to $ \sim0.8%$ , reflecting a $ 67%$ error reduction compared to the original FVC functional ($ MRE = 2.4%$ ). As simulation time grows almost linearly with dimension, our results highlight the potential of ant colony algorithms for density-functional problems, combining effectiveness with low computational cost.
Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph), Data Analysis, Statistics and Probability (physics.data-an)
7 pages,3 figures
Spin-Exchange Induced Spillover on Poor Man’s Majoranas in Minimal Kitaev Chains
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
J.E. Sanches, L.T. Lustosa, L.S. Ricco, H. Sigurðsson, M. de Souza, M.S. Figueira, E. Marinho Jr., A.C. Seridonio
The “Poor Man’s Majoranas” (PMMs) [Phys. Rev. B 86, 134528 (2012)] devoid of topological protection can “spill over” from one edge into another of the minimal Kitaev chain when perturbed electrostatically. As aftermath, this leads to a delocalized Majorana fermion (MF) at both the edges. Additionally, according to recent differential conductance measurements in a pair of superconducting and spinless quantum dots (QDs), such a PMM picture was brought to reality [Nature 614, 445 (2023) and Nature 630, 329 (2024)]. Based on this scenario, we propose the spillover of the PMM when its QD is exchange coupled to a quantum spin $ S$ . We show that if this QD is perturbed by the exchange coupling $ J$ , solely the half $ 2S+1$ $ (2S+2)$ of the fine structure stays explicit for a fermionic (bosonic) $ S.$ Concurrently, the other half squeezes itself as the delocalized MF zero-mode. Particularly, turning-off the superconductivity the multiplicity $ 2S+1$ holds regardless the spin statistics. Meanwhile, the PMM spillover induced by $ J$ becomes a statistics dependent effect. Hence, our findings contribute to the comprehension of spin-phenomena interplay with superconductivity in minimal Kitaev chains, offering insights for future quantum computing devices hosting PMMs.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
Journal of Physics: Condensed Matter, Volume 37, Number 20, 205601 (2025)
2D Active Brownian run-and-tumble particles moment analysis
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-30 20:00 EDT
Aoran Sun, Da Wei, Yiyu Zhang, Fangfu Ye, Rudolf Podgornik
We study an active Brownian run-and-tumble particle (ABRTP) model, that consists of an active Brownian run state during which the active velocity of the particle diffuses on the unit circle, and a tumble state during which the active velocity is zero, both with exponentially distributed time. Additionally we add a harmonic trap as an external potential. In the appropriate limits the ABRTP model reduces either to the active Brownian particle model, or the run-and-tumble particle model. Using the method of direct integration the equation of motion, pioneered by Kac, we obtain exact moments for the Laplace transform of the time dependent ABRTP, in the presence or absence of a harmonic trap. In addition we estimate the distribution moments with the help of the Chebyshev polynomials. Our results are in excellent agreement with the experiments.
Statistical Mechanics (cond-mat.stat-mech)
12 pages, 4 figures
Sparse mixed linear modeling with anchor-based guidance for high-entropy alloy discovery
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-30 20:00 EDT
Ryo Murakami, Seiji Miura, Akihiro Endo, Satoshi Minamoto
High-entropy alloys have attracted attention for their exceptional mechanical properties and thermal stability. However, the combinatorial explosion in the number of possible elemental compositions renders traditional trial-and-error experimental approaches highly inefficient for materials discovery. To solve this problem, machine learning techniques have been increasingly employed for property prediction and high-throughput screening. Nevertheless, highly accurate nonlinear models often suffer from a lack of interpretability, which is a major limitation. In this study, we focus on local data structures that emerge from the greedy search behavior inherent to experimental data acquisition. By introducing a linear and low-dimensional mixture regression model, we strike a balance between predictive performance and model interpretability. In addition, we develop an algorithm that simultaneously performs prediction and feature selection by considering multiple candidate descriptors. Through a case study on high-entropy alloys, this study introduces a method that combines anchor-guided clustering and sparse linear modeling to address biased data structures arising from greedy exploration in materials science.
Materials Science (cond-mat.mtrl-sci), Applications (stat.AP), Methodology (stat.ME), Machine Learning (stat.ML)
Hydrostatic equilibrium in multi-Weyl semimetals
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-30 20:00 EDT
Jewel Kumar Ghosh, Francisco Peña-Benítez, Patricio Salgado-Rebolledo
We study the hydrostatic equilibrium of multi-Weyl semimetals, a class of systems with Weyl-like quasi-particles but anisotropic dispersion relation $ \omega^2 \sim k_\parallel^2 + k_\perp^{2n}$ , with $ n$ a possitive integer. A characteristic feature of multi-Weyl systems is the lack of Lorentz invariance, instead, they possess the reduced spacetime symmetry $ (SO(1,1)\times SO(2))\ltimes \mathbb R^4$ . In this work we propose a covariant formulation for the low energy theory, allowing for a minimal coupling of the fermion field to external geometric background and $ U(1)$ gauge field. The non-Lorentzian structure of the field theory demands introducing an Aristotelian spacetime analogous to the so-called stringy Newton-Cartan geometry \cite{Andringa:2012uz}. Our proposal allows for a systematic study of the hydrostatic properties via the derivation of the partition function of the system. In addition to multi-Weyl models, our formulation can be applied to systems with similar spacetime symmetry groups, such as Bjorken flow.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th)
23 pages
Quantized resonant tunneling effect in Josephson junctions with ferromagnetic bilayers
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-30 20:00 EDT
Hao Meng, Xiuqiang Wu, Jiansheng Wu
We study the Josephson effect in SF$ _1$ F$ _2$ S junctions, which consist of conventional s-wave superconductors (S) connected by two ferromagnets (F$ 1$ and F$ 2$ ). At low temperatures, the Josephson critical current displays periodic resonance peaks as exchange fields ($ h_1$ , $ h_2$ ) and thicknesses ($ d_1$ , $ d_2$ ) of the F$ 1$ and F$ 2$ layers vary, provided a potential barrier exists at the F$ 1$ /F$ 2$ interface. These resonance peaks emerge under the quantization conditions $ Q{1(2)}d{1(2)}=\left(n{1(2)}+1/2\right)\pi$ . Here, $ Q{1(2)} = 2h{1(2)}/(\hbar v_F)$ represents a center-of-mass momentum carried by Cooper pairs, where $ v_F$ is the Fermi velocity and $ n{1(2)} = 0, 1, 2, \cdots$ . This critical current feature arises from a resonant tunneling effect induced by spin-triplet pairs with zero spin projection along the magnetization axis. At resonance, the Josephson current primarily originates from the first harmonic in both parallel and antiparallel magnetization configurations, whereas the second harmonic becomes more significant in perpendicular configurations. In cases where both ferromagnetic layers have identical exchange fields and thicknesses, the potential barrier selectively suppresses the current in the 0-state while maintaining it in the $ \pi$ -state for parallel configurations. Conversely, in antiparallel configurations, the current in the 0-state is consistently preserved.
Superconductivity (cond-mat.supr-con)
Emergent superconductivity and non-reciprocal transport in a van der Waals Dirac semimetal/antiferromagnet heterostructure
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-30 20:00 EDT
Saurav Islam, Max Stanley, Anthony Richardella, Seungjun Lee, Kalana D. Halanayake, Sandra Santhosh, Danielle Reifsnyder Hickey, Tony Low, Nitin Samarth
We investigate emergent superconductivity and non-reciprocal transport (magnetochiral anisotropy, superconducting diode effect) at the heterointerface of two non-superconducting van der Waals (vdW) materials, the Dirac semimetal ZrTe$ _2$ and the antiferromagnetic iron chalcogenide FeTe, grown using molecular beam epitaxy. We show from electrical transport measurements that two dimensional (2D) superconductivity arises at the heterointerface below temperature $ T \sim 12$ ~K. When capped with a 2D ferromagnet (CrTe$ _2$ ), these heterostructures show a superconducting diode effect with efficiency of about 30%. With strong spin-orbit coupling in ZrTe$ _2$ , these epitaxial heterostructures provide an attractive epitaxial vdW platform for exploring unconventional superconductivity in Dirac semimetals and for developing non-reciprocal devices for superconducting electronics.
Superconductivity (cond-mat.supr-con)
Deterministic Formation of Single Organic Color Centers in Single-Walled Carbon Nanotubes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-30 20:00 EDT
Daichi Kozawa, Yuto Shiota, Yuichiro K. Kato
Quantum light sources using single-walled carbon nanotubes show promise for quantum technologies but face challenges in achieving precise control over color center formation. Here we present a novel technique for deterministic creation of single organic color centers in carbon nanotubes using \textit{in-situ} photochemical reaction. By monitoring discrete intensity changes in photoluminescence spectra, we achieve precise control over the formation of individual color centers. Furthermore, our method allows for position-controlled formation of color centers as validated through photoluminescence imaging. We also demonstrate photon antibunching from a color center, confirming the quantum nature of the defects formed. This technique represents a significant step forward in the precise engineering of atomically defined quantum emitters in carbon nanotubes, facilitating their integration into advanced quantum photonic devices and systems.
Materials Science (cond-mat.mtrl-sci)
8 pages, 5 figures
Tunable Thermal Expansion in Functionalized 2D Boron Nitride: A First-Principles Investigation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-30 20:00 EDT
Sk Mujaffar Hossain, Dobin Kim, Jaehyun Park, Seung-Cheol Lee, Satadeep Bhattacharjee
This study investigates the thermal expansion coefficient of two-dimensional (2D) functionalized boron nitride (f-BN) materials using first-principles density functional theory (DFT). Two-dimensional materials, particularly hexagonal boron nitride (h-BN), have attracted significant attention due to their exceptional mechanical, thermal, and electronic properties. However, the influence of functionalization on the thermal expansion behavior remains largely unexplored. In this work, DFT calculations are employed to analyze how different functionalized forms of h-BN impact the thermal expansion of BN sheets. Density functional perturbation theory (DFPT) and the quasiharmonic approximation (QAH) are utilized to determine the thermal expansion coefficient over a range of temperatures. The results reveal that functionalization induces notable modifications in the in-plane thermal expansion of BN, affecting material stability and suggesting potential applications in nanoelectronics and thermal management. This investigation provides critical insights into the tunability of the thermal properties of 2D BN, underscoring its suitability for next-generation flexible and high-performance devices.
Materials Science (cond-mat.mtrl-sci)
Moiré Band Engineering in Twisted Trilayer WSe2
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Naoto Nakatsuji, Takuto Kawakami, Hayato Tateishi, Koichiro Kato, Mikito Koshino
We present a systematic theoretical study on the structural and electronic properties of twisted trilayer transition metal dichalcogenide (TMD) WSe$ _2$ , where two independent moiré patterns form between adjacent layers. Using a continuum approach, we investigate the optimized lattice structure and the resulting energy band structure, revealing fundamentally different electronic behaviors between helical and alternating twist configurations. In helical trilayers, lattice relaxation induces $ \alpha\beta$ and $ \beta\alpha$ domains, where the two moiré patterns shift to minimize overlap, while in alternating trilayers, $ \alpha\alpha’$ domains emerge with aligned moiré patterns. A key feature of trilayer TMDs is the summation of moiré potentials from the top and bottom layers onto the middle layer, effectively doubling the potential depth. In helical trilayers, this mechanism generates a Kagome lattice potential in the $ \alpha\beta$ domains, giving rise to flat bands characteristic of Kagome physics. In alternating trilayers, the enhanced potential confinement forms deep triangular quantum wells, distinct from those found in bilayer systems. Furthermore, we demonstrate that a moderate perpendicular electric field can switch the layer polarization near the valence band edge, providing an additional degree of tunability. In particular, it enables tuning of the hybridization between orbitals on different layers, allowing for the engineering of diverse and controllable electronic band structures. Our findings highlight the unique role of moiré potential summation in trilayer systems, offering a broader platform for designing moiré-based electronic and excitonic phenomena beyond those achievable in bilayer TMDs.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
24 pages, 17 figures
Exact multiple complex mobility edges and quantum state engineering in coupled 1D quasicystals
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-04-30 20:00 EDT
Li Wang, Zhenbo Wang, Jiaqi Liu, Shu Chen
The key concept of mobility edge, which marks the critical transition between extended and localized states in energy domain, has attracted significant interest in the cutting-edge frontiers of modern physics due to its profound implications for understanding localization and transport properties in disordered systems. However, a generic way to construct multiple mobility edges (MME) is still ambiguous and lacking. In this work, we propose a brief scheme to engineer both real and complex exact multiple mobility edges exploiting a few coupled one-dimensional quasiperiodic chains. We study the extended-localized transitions of coupled one-dimensional quasiperiodic chains along the chain direction. The model combines both the well-established quasiperiodicity and a kind of freshly introduced staggered non-reciprocity, which are aligned in two mutually perpendicular directions, within a unified framework. Based on analytical analysis, we predict that when the couplings between quasiperiodic chains are weak, the system will be in a mixed phase in which the localized states and extended states coexist and intertwine, thus lacking explicit energy separations. However, as the inter-chain couplings increase to certain strength, exact multiple mobility edges emerge. This prediction is clearly verified by concrete numerical calculations of the Fractal Dimension and the scaling index $ \beta$ . Moreover, we show that the combination of quasiperiodicity and the staggered non-reciprocity can be utilized to design and realize quantum states of various configurations. Our results reveal a brief and general scheme to implement exact multiple mobility edges for synthetic materials engineering.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
Spin-orbital order and excitations in $3d^4$, $4d^4$, and $5d^4$ systems: Application to $\rm BaFeO_3$, $\rm Sr_2RuO_4$, $\rm Sr_2YIrO_6$, and $\rm K_2OsCl_64$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-30 20:00 EDT
Shahid Ahmad, Harshvardhan Parmar, Shubhajyoti Mohapatra, Avinash Singh
Evolution of composite spin-orbital order and coupled spin-orbital excitations is studied in a variety of $ d^4$ systems with $ n$ =$ 4$ electrons in the $ t_{2g}$ orbital sector using the generalised self-consistent + fluctuations approach for a realistic interacting-electron model. Within this unified approach, applications are discussed to compounds with $ 3d$ , $ 4d$ , $ 5d$ transition-metal ions such as $ \rm BaFeO_3$ ($ \rm Fe^{4+}$ ), $ \rm Ca_2RuO_4$ ($ \rm Ru^{4+}$ ), $ \rm Sr_2RuO_4$ ($ \rm Ru^{4+}$ ), $ \rm Sr_2YIrO_6$ ($ \rm Ir^{5+}$ ), and $ \rm K_2OsCl_6$ ($ \rm Os^{4+}$ ). Continuous interpolation from the nominally $ S=1$ antiferromagnetic order in $ \rm Ca_2RuO_4$ (strong crystal field, intermediate spin-orbit coupling (SOC) and Coulomb interaction) to the $ J=0$ state relevant for $ 5d^4$ compounds (strong SOC, weak Coulomb interaction) and to the half-metallic ferromagnetic order when crystal field is negligible as in $ \rm BaFeO_3$ (weak SOC, strong Coulomb interaction) and $ \rm Sr_2RuO_4$ (intermediate SOC and Coulomb interaction) provides new fundamental insights into the magnetism of spin-orbit coupled systems.
Strongly Correlated Electrons (cond-mat.str-el)
23 pages, 9 figures
Self-consistency error correction for accurate machine learning potentials from variational Monte Carlo
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-30 20:00 EDT
Giacomo Tenti, Kousuke Nakano, Michele Casula
Variational Monte Carlo (VMC) can be used to train accurate machine learning interatomic potentials (MLIPs), enabling molecular dynamics (MD) simulations of complex materials on time scales and for system sizes previously unattainable. VMC training sets are often based on partially optimized wave functions (WFs) to circumvent expensive energy optimizations of the whole set of WF parameters. However, frozen variational parameters lead to VMC forces and pressures not consistent with the underlying potential energy surface, a bias called the self-consistency error (SCE). Here, we demonstrate how the SCE can spoil the accuracy of MLIPs trained on these data, taking high-pressure hydrogen as test case. We then apply a recently introduced SCE correction [ Phys. Rev. B 109, 205151 (2024)] to generate unbiased VMC training sets based on a Jastrow-correlated single determinant WF with frozen Kohn-Sham orbitals. The MLIPs generated within this framework are significantly improved and can approach in quality those trained on datasets built with fully optimized WFs. Our conclusions are further supported by MD simulations, which show how MLIPs trained on SCE-corrected datasets systematically yield more reliable physical observables. Our framework opens the possibility of constructing extended high-quality training sets with VMC.
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci)
Laser-induced modulation of the ferromagnetic-antiferromagnetic phase fraction in FeRh films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-30 20:00 EDT
Alexis Pecheux (ENS Paris Saclay, SATIE, CNRS), Robin Salvatore (INSP, SU, CNRS), Laura Thevenard (INSP, SU, CNRS), Jon Ander Arregi, Vojtěch Uhlíř, Morgan Almanza (ENS Paris Saclay, CNRS, SATIE), Danièle Fournier (INSP, SU, CNRS), Catherine Gourdon (INSP, SU, CNRS), Martino Lobue (ENS Paris Saclay, CNRS, SATIE)
With his huge entropy change and a strong interplay between magnetic order, structural and electrical properties, the first-order antiferromagnetic/ferromagnetic phase transition is a paradigmatic example of the multicaloric effect. The unraveling of the physics underlying the phase transition needs a better understanding of the thermal hysteresis of FeRh within the AF-FM phase coexistence region. In this work, we compare the effect of two very different types of thermal cycling on the hysteresis of the magnetic order: quasi-static heating, and cooling of the entire 195 nm thick film, and a f =100 kHz modulated heating driven by a laser focused down to a spot of about ten micron squared at the film surface. Taking advantage of the reflectivity difference between both phases to probe optically their respective fraction, we show that whereas only temperature-driven reflectivity variations (dR/dT , thermoreflectance) are detected in the pure phases, a huge modulation of the phase-dependent reflectance at the driving frequency f is detected in the phase coexistence temperature range. This is quantitatively described as resulting from a substantial modulation of the FM fraction (up to 90%) with increasing laser power. A simplified rate-independent hysteresis model with return-point-memory (RPM), represented in terms of bistable units that undergo a temperature excursion corresponding to a given laser power, reproduces very well the optically measured FM phase modulation characteristics for a broad range of temperature excursions. This offers an insight into the leading role of quenched disorder in defining thermal hysteresis in FeRh under high excitation frequency, when the material is periodically driven out-of-equilibrium.
Materials Science (cond-mat.mtrl-sci)
Spin Wave Dispersion of the van der Waals Antiferromagnet NiPS$_3$
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Ritesh Das, Rob den Teuling, Artem V. Bondarenko, Elena V. Tartakovskaya, Gerrit E. W. Bauer, Jaime Ferrer, Yaroslav M. Blanter
We calculate the magnon dispersion spectra of the two-dimensional zigzag van der Waals antiferromagnet NiPS$ _3$ for monolayer, bilayer, and bulk systems as a function of an external magnetic field. We calculate the exchange and anisotropy constants in our spin model by first principles. We can accurately explain the transition from a collinear to a canted ground state for a magnetic field applied normal to the (in-plane) easy-axis, and a spin-flop transition when the field is parallel to it. A topologically protected Dirac nodal line is present and robust with respect to both external and anisotropy fields.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
12 pages, 12 figures
A foundry-fabricated spin qubit unit cell with in-situ dispersive readout
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Pierre Hamonic, Mathieu Toubeix, Guillermo Haas, Jayshankar Nath, Matthieu C. Dartiailh, Biel Martinez, Benoit Bertrand, Heimanu Niebojewski, Maud Vinet, Christopher Bäuerle, Franck Balestro, Tristan Meunier, Matias Urdampilleta
Spin qubits based on semiconductor quantum dots are a promising prospect for quantum computation because of their high coherence times and gate fidelities. However, scaling up those structures to the numbers required by fault-tolerant quantum computing is currently hampered by a number of issues. One of the main issues is the need for single-shot low-footprint qubit readout. Here, we demonstrate the single-shot in situ measurement of a compact qubit unit-cell. The unit cell is composed of two electron spins with a controllable exchange interaction. We report initialization, single-shot readout and two-electron entangling gate. The unit cell was successfully operated at up to 1 K, with state-of-the-art charge noise levels extracted using free induction decay. With its integrated readout and high stability, this foundry fabricated qubit unit cell demonstrates strong potential for scalable quantum computing architectures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
18 pages, 7 figures
Collapse of molecular orbital by ultrahigh magnetic fields in V$6$O${13}$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-30 20:00 EDT
Yuto Ishii, Akihiko Ikeda, Yasuhiro. H. Matsuda
V$ _6$ O$ _{13}$ exhibits the metal-insulator transition (MIT) with vanadium-vanadium (V-V) dimer formation. The magnetostriction of V$ _6$ O$ _{13}$ along the crystallographic $ b$ -axis has been measured in ultrahigh magnetic fields up to 186 T at several temperatures in this work. The large negative magnetostriction as large as $ \Delta L / L \sim10^{-3}$ was observed above 110 T below the transition temperature. Discussion based on experimental results and the physical property of V$ _6$ O$ _{13}$ suggests that the observed large negative magnetostriction corresponds to the collapse of V-V dimer molecular orbital (MO). This is the first case for direct observation of lattice change originating from the magnetic field-induced collapse of V-V dimer MO in vanadium oxides. In addition, the $ B$ -$ T$ phase diagram and the magnitude of magnetostriction indicate that the collapse of V-V dimer MO probably accompanies the insulator-to-metal transition. A large hysteresis that is larger than 50 T was observed, which probably arises from the non-equilibrated cross-correlation of such degrees of freedom as the charge, spin, and lattice. Comparison with the VO$ _2$ case suggests the magnetic entropy of the remanent paramagnetic spins in the insulating phase may play an important role for the MIT in V$ _6$ O$ _{13}$ .
Strongly Correlated Electrons (cond-mat.str-el)
Electroactive differential growth and delayed instability in accelerated healing tissues
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-30 20:00 EDT
Yafei Wang, Zhanfeng Li, Xingmei Chen, Yun Tan, Fucheng Wang, Yangkun Du, Yunce Zhang, Yipin Su, Fan Xu, Changguo Wang, Weiqiu Chen, Ji Liu
Guided by experiments contrasting electrically accelerated recovery with natural healing, this study formulates a model to investigate the importance of electroactive differential growth and morphological changes in tissue repair. It underscores the clinical potential of leveraging electroactive differential growth for improved healing outcomes. The study reveals that voltage stimulation significantly enhances the healing and growth of biological tissues, accelerating the regeneration process across various growth modalities and steering towards isotropic growth conditions that do not favor any specific growth pathways. Enhancing the electroelastic coupling parameters improves the efficacy of bioelectric devices, initiating contraction and fortification of biological tissues in alignment with the electric field. This process facilitates swift cell migration and proliferation, as well as oriented growth of tissue. In instances of strain stiffening at elevated strains, the extreme critical growth ratio aligns with the predictions of neo-Hookean models. Conversely, for tissues experiencing strain stiffening under moderate to very low strain conditions, the strain stiffening effect substantially delays the onset of electroelastic growth instability, ultimately producing a smooth, hyperelastic surface devoid of any unstable morphologies. Our investigation, grounded in nonlinear electroelastic field and perturbation theories, explores how electric fields influence differential growth and instability in biological tissues. We examine the interactions among dimensionless voltage, internal pressure, electroelastic coupling, radius ratio, and strain stiffening, revealing their effects on promoting growth and delaying instability. This framework offers insights into the mechanisms behind electroactive growth and its instabilities, contributing valuable knowledge to the tissue healing.
Soft Condensed Matter (cond-mat.soft)
Journal of Mechanics and Physics of Solids 2024
A DFT study on 18-crown-6-like-N$_8$ structure as a material for metal-ions storage: stability and performance
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-30 20:00 EDT
Irina I. Piyanzina, Regina M. Burganova, Sadegh Kaviani, Oleg V. Nedopekin, Hayk Zakaryan
Developing electrode materials with exceptional electrical conductivity, robust chemical stability, rapid charge and discharge rates, and high storage capacity is essential for advancing high-performance metal-ion batteries. This study explores the two-dimensional, 18-crown-6-like N8 structure (2D-N8) as a promising electrode material for next-generation rechargeable post-lithium batteries. We thoroughly investigated the pristine N8 structures, focusing on their stability and performance metrics. Our analysis revealed remarkable structural stability across the board. Additionally, electronic calculations indicated a small band gap of 0.54 eV for the N8 monolayer, suggesting favorable electronic properties for battery applications. When we evaluated a series of metal ions as adsorbates, we found that the pristine N8 monolayer achieved an impressive storage capacity of 1675 mAh/g for sodium (Na) and magnesium (Mg) ions, highlighting its potential for effective ion storage. Our findings suggest that the engineered 2D-N8 structure offers a unique combination of stability and electrochemical performance that could significantly contribute to developing efficient and durable energy storage technologies.
Materials Science (cond-mat.mtrl-sci)
Hydrodynamics converts chiral flagellar rotation into contactless actuation of microdiscs
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-30 20:00 EDT
Daniel Grober, Tanumoy Dhar, David Saintillan, Jérémie Palacci
Motile bacteria are a wonder of nature’s engineering: microscopic engines that transduce biochemical energy into the work they require to explore their environment. This added energy turns the surrounding fluid into a bath that departs from an equilibrium one. Bacterial baths agitate suspended spheres more vividly than thermal fluctuations and can power microscopic ratchets. A salient requirement to extract work from bacterial baths was the asymmetric shape of the ratchets, designed to rectify the interactions with bacteria. In contrast with past results, here we show that swimming E. coli power the persistent rotation of discs, in absence of asymmetry. Combining state-of-the art nanoprinting, quantitative measurements of the dynamics of individual bacteria, and hydrodynamic modeling, we elucidate the mechanism and show that the counter-rotation of the flagella and the bacterium body lead to a torque dipole and traction onto the disc, and subsequent rotation. Remarkably, the mechanism is independent of the direction or orientation of navigation of bacteria under the disc, hence additive and contactless. Resulting from the interplay of the torque dipole of flagellated bacteria with simple geometric confinement, this hydrodynamic mechanism bridges scales, leveraging the chirality of bacteria nanomotors towards the manipulation of objects at least ten thousand times larger. The study lays the groundwork for novel bio-hybrid micromachines that harness living microorganisms for controlled motion at the microscale. Our findings provide further fundamental insights into bacterial hydrodynamics and open avenues for the development of autonomous, self-powered microdiscs for the study of chiral fluids.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
Inhomogeneous Diffusion in Confined Colloidal Suspensions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-30 20:00 EDT
Gerhard Jung, Alejandro Villada-Balbuena, Thomas Franosch
We have performed confocal microscopy experiments and computer simulations of colloidal suspensions with moderate volume fraction confined between two quasi-parallel, rough walls [A. Villada-Balbuena et al., Soft Matter, 2022, 18, 4699-4714]. Here we investigate many facets of the dynamical properties of the system, such as confined and inhomogeneous diffusion, mean first-passage times and generalized incoherent scattering functions. We observe that the experiment features strong footprints of the confinement in the dynamical properties, such as inhomogeneous diffusion coefficients and non-zero off-diagonal elements in the incoherent scattering function which we can quantitatively model and analyze with computer simulations. This allows us, for example, to systematically investigate the impact of surface roughness. Our comparative study therefore advances the fundamental understanding of the impact of confinement on dynamics in fluids and colloidal suspensions.
Soft Condensed Matter (cond-mat.soft)
Soft Matter (2025)
Microcanonical ensemble out of equilibrium
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-30 20:00 EDT
Roman Belousov, Jenna Elliott, Florian Berger, Lamberto Rondoni, Anna Erzberger
Introduced by Boltzmann under the name “monode,” the microcanonical ensemble serves as the fundamental representation of equilibrium thermodynamics in statistical mechanics by counting all realizations of a system’s states. Ensemble theory connects this idea with probability and information theory, leading to the notion of Shannon-Gibbs entropy and, ultimately, to the principle of maximum caliber describing trajectories of systems in and out of equilibrium. While the latter generalization reproduces many results of nonequilibrium thermodynamics, given a proper choice of observables, its physical justification remains an open area of research. What is the microscopic origin and physical interpretation of this variational approach? What guides the choice of relevant observables? We address these questions by extending Boltzmann’s method to a microcanonical caliber principle and counting realizations of a system’s trajectories–all assumed equally probable. Maximizing the microcanonical caliber under the imposed macro- and microscopic constraints, we systematically develop generalized detailed-balance relations, clarify the statistical origins of inhomogeneous transport, and provide an independent derivation of key equations underlying the theories of random walks and stochastic thermodynamics. This approach introduces a dynamical ensemble theory for nonequilibrium steady states in spatially extended and active systems. While verifying the equivalence of ensembles, e.g. those of Norton and Thevenin, our theory highlights differences between nonequilibrium regimes not evident in the traditional formulation of the maximum-caliber principle. We validate our results by stochastic simulations. Our theory suggests further connections to the first principles of microscopic dynamics, which are critical for investigating systems where the conditions for thermodynamic behavior are not satisfied.
Statistical Mechanics (cond-mat.stat-mech)
19 pages, 3 figures
Inhomogeneous Phase Stiffness in $2$D $s$-wave Disordered Superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-30 20:00 EDT
Sudipta Biswas, A. Taraphder, Sudhansu S. Mandal
We investigate the effect of white-noise disorder on the local phase stiffness and thermodynamic properties of a two-dimensional $ s$ -wave superconductor. Starting from a local attractive model and using path-integral formalism, we derive an effective action by decoupling the superconducting order parameter into amplitude and phase components in a gauge-invariant manner. Perturbative techniques are applied to the phase fluctuation sector to derive an effective phase-only XY model for disordered superconducting systems. Solving the saddle-point Green’s function using Bogoliubov-de Gennes theory, we calculate the distributions of nearest-neighbor couplings for various disorder strengths. A single-peak distribution is observed for low disorder strength, which becomes bimodal with one peak at negative couplings as the disorder strength increases. The local phase stiffness remains randomly distributed throughout the lattice and shows no correlation with pairing amplitudes. The temperature dependence of the superfluid stiffness ($ J_s$ ) is studied using Monte Carlo simulations. At strong disorder and low temperatures, $ J_s$ increases with increasing temperature, exhibiting anomalous behavior that may indicate the onset of a glassy transition. Additionally, calculations of the Edwards-Anderson order parameter in this disorder regime suggest the emergence of a $ phase$ -$ glass$ state at very low temperatures.
Superconductivity (cond-mat.supr-con)
12 pages, 6 figures
Hamiltonian learning of triplon excitations in an artificial nanoscale molecular quantum magnet
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Rouven Koch, Robert Drost, Peter Liljeroth, Jose L. Lado
Extracting the Hamiltonian of nanoscale quantum magnets from experimental measurements is a significant challenge in correlated quantum matter. Here we put forward a machine learning strategy to extract the spin Hamiltonian from inelastic spectroscopy with scanning tunneling microscopy, and we demonstrate this methodology experimentally with an artificial nanoscale molecular magnet based on cobalt phthalocyanine (CoPC) molecules on NbSe$ _2$ . We show that this technique allows to directly extract the Hamiltonian parameters of a quantum magnet from the differential conductance, including the substrate-induced spatial variation of the different exchange couplings. Our methodology leverages a machine learning algorithm trained on exact quantum many-body simulations with tensor networks of finite quantum magnets, leading to a methodology that can be used to predict the Hamiltonian of CoPC quantum magnets of arbitrary size. Our results demonstrate how quantum many-body methods and machine learning enable learning a microscopic description of nanoscale quantum many-body systems with scanning tunneling spectroscopy.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
5 pages, 5 figures, supplementary information
AIM: A User-friendly GUI Workflow program for Isotherm Fitting, Mixture Prediction, Isosteric Heat of Adsorption Estimation, and Breakthrough Simulation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-30 20:00 EDT
Muhammad Hassan, Sunghyun Yoon, Yu Chen, Pilseok Kim, Hongryeol Yun, Hyuk Taek Kwon, Youn-Sang Bae, Chung-Yul Yoo, Dong-Yeun Koh, Chang-Seop Hong, Ki-Bong Lee, Yongchul G. Chung
Adsorption breakthrough modeling often requires complex software environments and scripting, limiting accessibility for many practitioners. We present AIM, a MATLAB-based graphical user interface (GUI) application that streamlines fixed-bed adsorption analysis through an integrated workflow for isotherm fitting, heat of adsorption estimation, mixture prediction, and multicomponent breakthrough simulations. AIM’s intuitive GUI requires no coding and supports a broad isotherm library (e.g., Langmuir, Toth, Dubinin-Astakhov, Structural-Transition-Adsorption). It also enables non-isothermal breakthrough simulations with axial dispersion. Case studies, such as Xe/Kr breakthrough curves in SBMOF-1, closely match the results from other software applications, such as RUPTURA. Mixture predictions can be done using the Ideal Adsorbed Solution Theory (IAST) and Extended Langmuir models, while isosteric heats are derived from Clausius-Clapeyron or Virial equations. Users can export detailed column and outlet profiles (e.g., composition, temperature) in multiple formats, enhancing reproducibility and data sharing among practitioners.
Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech)
70 pages, 15 figures
Frequency dependence of temporal spin stiffness and short-range magnetic order in the doped two-dimensional Hubbard model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-30 20:00 EDT
I. A. Goremykin, A. A. Katanin
We study doping and temperature dependencies of temporal and spatial spin stiffnesses of the Hubbard model within the mean field approach for incommensurate magnetic order. We show that the frequency dependence of temporal spin stiffness is crucial to obtain small values of correlation length, comparable to those observed in cuprates. Using the obtained spin stiffnesses, we obtain the temperature and doping dependence of correlation length within the large-$ N$ limit of the respective nonlinear sigma model. In agreement with the experimental data on La$ _{2-x}$ Sr$ _x$ CuO$ _4$ we obtain short range magnetic order with relatively small correlation length at $ 0.1 \lesssim x\lesssim 0.2$ , and magnetically ordered ground state in the narrow doping region $ 0.05\lesssim x \lesssim 0.1$ . The latter state may correspond to the spin-frosen state, observed in the experimental data on La$ _{2-x}$ Sr$ _x$ CuO$ _4$ .
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
7+6 pages, 3+5 figures
Particle-Hole Asymmetry and Pinball Liquid in a Triangular-Lattice Extended Hubbard Model within Mean-Field Approximation
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-30 20:00 EDT
Aleksey Alekseev, Agnieszka Cichy, Konrad Jerzy Kapcia
Recently, triangular lattice models have received a lot of attention since they can describe a number of strongly-correlated materials that exhibit superconductivity and various magnetic and charge orders. In this research we present an extensive analysis of the charge-ordering phenomenon of the triangular-lattice extended Hubbard model with repulsive onsite and nearest-neighbor interaction, arbitrary charge concentration, and $ \sqrt{3}\times\sqrt{3}$ supercell (3-sublattice assumption). The model is solved in the ground state with the mean-field approximation which allowed to identify $ 8$ charge-ordered phases and a large variety of phase transitions. An exotic pinball-liquid phase was found and described. Moreover, strong particle-hole asymmetry of the phase diagram is found to play an important role for triangular lattices. The analysis of band structures, unavailable for more advanced methods that take into account correlation effects, provided a great insight in the nature of triangular-lattice phases and phase transitions. The complexity of the mean-field phase diagram showed the importance and usefulness of the results for the further research with correlation effects included. Together with atomic-limit approximation it can serve them as both a starting point, and a tool to interpret results.
Strongly Correlated Electrons (cond-mat.str-el), Other Condensed Matter (cond-mat.other), Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech), Computational Physics (physics.comp-ph)
11 pages, 6 figures, 74 references; RevTeX class, double-column formatting, includes also Supplemental Materials (5 pages, 3 figures, 9 multimedia filies)
Nonsymmorphic Topological Phases of Non-Hermitian Systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Daichi Nakamura, Yutaro Tanaka, Ken Shiozaki, Kohei Kawabata
Non-Hermiticity appears ubiquitously in various open classical and quantum systems and enriches classification of topological phases. However, the role of nonsymmorphic symmetry, crystalline symmetry accompanying fractional lattice translations, has remained largely unexplored. Here, we systematically classify non-Hermitian topological crystalline phases protected by nonsymmorphic symmetry and reveal unique phases that have no counterparts in either Hermitian topological crystalline phases or non-Hermitian topological phases protected solely by internal symmetry. Specifically, we elucidate the $ \mathbb{Z}_2$ and $ \mathbb{Z}_4$ non-Hermitian topological phases and their associated anomalous boundary states characterized by distinctive complex-valued energy dispersions.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Mathematical Physics (math-ph), Quantum Physics (quant-ph)
7+16 pages, 3+1 figures, 1+6 tables
Geometric potential for a Bose-Einstein condensate on a curved surface
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-30 20:00 EDT
Sheilla M. de Oliveira, Natália Salomé Móller
We compute the ground state of a Bose-Einstein condensate confined on a curved surface and unravel the effects of curvatures. Starting with a general formulation for any smooth surface, we apply it to a prolate ellipsoid, which is inspired by recent bubble trap experiments. Using a perturbative approach to the Gross-Pitaevskii equation and a general Ansatz, followed by a dimensional reduction, we derive an effective two-dimensional equation that includes a curvature-dependent geometric potential. We compute the ground state using Thomas-Fermi approximation and, for an isotropic confinement, we find that the highest accumulation of atoms happens on the regions with the greatest difference between the principal curvatures. For a prolate ellipsoid, this accumulation happens on the equator, which is contrary to previous findings that describe accumulation on the poles of a bubble trap. Finally, we explain the reasons for this difference: the higher accumulation of atoms on the poles happens due to anisotropies in the confinement, while the higher accumulation on the equator happens exclusively due to the geometric properties of the surface.
Quantum Gases (cond-mat.quant-gas)
20 pages and 4 figures in the main text. 30 pages and 5 figures in total
Flexible Perovskite/Silicon Monolithic Tandem Solar Cells Approaching 30% Efficiency
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-30 20:00 EDT
Yinqing Sun, Faming Li, Hao Zhang, Wenzhu Liu, Zenghui Wang, Lin Mao, Qian Li, Youlin He, Tian Yang, Xianggang Sun, Yicheng Qian, Yinyi Ma, Liping Zhang, Junlin Du, Jianhua Shi, Guangyuan Wang, Anjun Han, Na Wang, Fanying Meng, Zhengxin Liu, Mingzhen Liu
Thanks to their excellent properties of low cost, lightweight, portability, and conformity, flexible perovskite-based tandem solar cells show great potentials for energy harvesting applications, with flexible perovskite/c-silicon tandem solar cells particularly promising for achieving high efficiency. However, performance of flexible perovskite/c-silicon monolithic tandem solar cells still greatly lags, due to challenges in simultaneously achieving both efficient photocarrier transport and reliable mitigation of residual stress. Here, we reveal the critical role of perovskite phase homogeneity, for achieving high-efficient and mechanical-stable flexible perovskite/c-silicon heterojunction monolithic tandem solar cells (PSTs) with textured surface. Through ensuring high phase homogeneity, which promotes charge transfer across all facets of the pyramid on the textured substrates and releases the residual stress at the perovskite/c-silicon interface, we demonstrate flexible PSTs with a bending curvature of 0.44 cm-1, and a certified power conversion efficiency of 29.88% (1.04 cm2 aperture area), surpassing all other types of flexible perovskite-based photovoltaic devices. Our results can lead to broad applications and commercialization of flexible perovskite/c-silicon tandem photovoltaics.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Self-assembly and time-dependent control of active and passive triblock Janus colloids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-30 20:00 EDT
Juri Franz Schubert, Salman Fariz Navas, Sabine H. L. Klapp
We perform Brownian Dynamics (BD) simulations to explore the self-assembly of a two-dimensional model system of triblock Janus colloids as an example of “patchy” colloids forming complex structures. Previous experiments and simulation studies have shown that such systems are capable of forming a two-dimensional Kagome lattice at room temperatures. However, it is well established that the crystallization is strongly hampered by the formation of long-living metastable aggregates. For this reason, recent studies have investigated activity, i.e., self-propulsion of the Janus particles as a mechanism to accelerate the formation of stable Kagome structures [Mallory and Cacciuto, JACS 141, 2500-2507 (2019)] at selected state points. Here we extend, first, the investigations of active Janus colloids for a broader range of densities and temperatures. We also characterize in detail the associated nucleation of Kagome clusters, as well as their structure in the steady state. Second, to make contact to the equilibrium case, we propose a simple activity time protocol where an initially chosen activity is switched off after a finite time. With this protocol, we not only find Kagome structures in a much broader range of densities than in the purely passive case, but also obtain a Kagome crystallization boundary very close to that proposed in earlier Monte Carlo simulations.
Soft Condensed Matter (cond-mat.soft)
The specific heat anomaly stems from a third-order phase transition in the 2D lattice sine-Gordon model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-30 20:00 EDT
Loris Di Cairano, Alexandre Tkatchenko
The specific heat anomaly (SHA) is broadly observed in statistical mechanics, appearing as a smooth, system-size-independent peak in the specific heat, in contrast to the singular behavior typical of second-order phase transitions (PTs). Its origin remains heavily debated: some attribute it to finite-size effects, others to unidentified phase transitions. Here we investigate SHA using the two-dimensional sine-Gordon (2D-sG) model and microcanonical inflection point analysis (MIPA), uncovering two key results. First, we show that the roughening transition in the 2D-sG model is a genuine third-order PT under MIPA, where the standard thermodynamic quantities remain continuous. This clarifies the ambiguity in the literature, where this transition was often, though inconclusively, attributed to a Berezinskii-Kosterlitz-Thouless (BKT) transition. Through the use of MIPA and a comprehensive analysis of standard thermodynamic observables, we provide a coherent thermodynamic characterization that redefines the nature of this transition. Second, we find that the SHA is not itself a PT but rather the thermodynamic fingerprint of this third-order transition. These findings clarify the nature of SHA within the 2D-sG model and suggest that similar anomalies in other systems, such as the XY model, may likewise originate from third-order PTs, rather than mere crossovers. Our results provide a consistent thermodynamic interpretation of the SHA and highlight the broader relevance of third-order transitions in systems previously thought to exhibit only low-order or crossover transition.
Statistical Mechanics (cond-mat.stat-mech)
Upper critical field and pairing symmetry of Ising superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-30 20:00 EDT
Lena Engström, Ludovica Zullo, Tristan Cren, Andrej Mesaros, Pascal Simon
Motivated by the fact that the measured critical field $ H_c$ in various transition metal dichalcogenide (TMD) superconductors is poorly understood, we reexamine its scaling behavior with temperature and spin-orbit coupling (SOC). By computing the spin-susceptibility in a multipocket system, we find that segments of the Fermi Surface (FS) at which the SOC has nodal points can have a contribution orders of magnitude larger than the remaining FS, hence setting the $ H_c$ , assuming the presence of a conventional singlet superconducting order parameter. Nodal lines of an Ising SOC in the Brillouin zone are imposed by symmetry, so they cause such nodal points whenever they intersect an FS pocket, which is indeed the case in monolayer NbSe$ _2$ and TaS$ _2$ , but not in gated MoS$ _2$ and WS$ _2$ . Our analysis reinterprets existing measurements, concluding that a dominant singlet-order parameter on pockets with SOC nodes is consistent with the $ H_c(T)$ data for all monolayer Ising superconductors, in contrast to previous contradictory pairing assumptions. Finally, we show that the theory is also consistent with data on homobilayer TMDs.
Superconductivity (cond-mat.supr-con)
5 pages, 3 figures
Critical clusters in liquid crystals: Fractal geometry and conformal invariance
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-30 20:00 EDT
Renan A. L. Almeida, Jeferson J. Arenzon
We study the two-dimensional domain morphology of twisted nematic liquid crystals during their phase-ordering kinetics [R. A. L. Almeida, Phys. Rev. Lett. 131 (2023) 268101], which is a physical candidate to self-generate critical clusters in the percolation universality class. Here we present experimental evidence that large clusters and their hulls are indeed both fractals with dimensions of the corresponding figures in critical percolation models. The asymptotic decay of a crossing probability, from a region in the vicinity of the origin to the boundary of disks, is described by the Lawler-Schramm-Werner theorem provided that a microscopic length in the original formulation is replaced by the coarsening length of the liquid crystal. Furthermore, the behavior for the winding angle of large loops is, at certain scales, compatible with that of Schramm-Loewner evolution curves with diffusivity $ \kappa = 6$ . These results show an experimental realization of critical clusters in phase ordering.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
6 pages
Phys. Rev. Lett. 134 (2025) 178101
Vibrational Energy Dissipation in Non-Contact Single-Molecule Junctions Governed by Local Geometry and Electronic Structure
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Lukas Hörmann, Reinhard J. Maurer
The vibrational dynamics of adsorbate molecules in single-molecule junctions depend critically on the geometric structure and electronic interactions between molecule and substrate. Vibrations, excited mechanochemically or by external stimuli, dissipate energy into substrate electrons and phonons. Energy dissipation leads to the broadening of spectral lines, vibrational lifetimes, and the coupling between molecular and substrate phonons. It affects molecular manipulation, giving rise to nanoscale friction, and contributes to scanning probe and surface spectroscopy signals. We present an approach to disentangle adsorbate vibrational dynamics in non-contact junctions by employing density functional theory, machine learning, and non-adiabatic molecular dynamics. Focusing on the CO-functionalised Cu surfaces representing a single-molecule junction, a widely studied system in scanning probe and energy dissipation experiments, we reveal strong vibrational mode specificity governed by the interplay of electron-phonon and phonon-phonon coupling. Electron-phonon relaxation rates vary by two orders of magnitude between modes and sensitively depend on the tip-substrate geometry. We find evidence of a weak non-additive effect between both energy dissipation channels, where electron-phonon coupling enhances phonon-phonon coupling. Our predicted vibrational lifetimes agree with infrared spectroscopy and helium scattering experiments. Finally, we outline how our findings can inform and enhance scanning probe experiments.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Materials Database from All-electron Hybrid Functional DFT Calculations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-30 20:00 EDT
Akhil S. Nair, Lucas Foppa, Matthias Scheffler
Materials databases built from calculations based on density functional approximations play an important role in the discovery of materials with improved properties. Most databases thus constructed rely on the generalized gradient approximation (GGA) for electron exchange and correlation. This limits the reliability of these databases, as well as the artificial intelligence (AI) models trained on them, for certain classes of materials and properties which are not well described by GGA. In this paper, we describe a database of 7,024 inorganic materials presenting diverse structures and compositions generated using hybrid functional calculations enabled by their efficient implementation in the all-electron code FHI-aims. The database is used to evaluate the thermodynamic and electrochemical stability of oxides relevant to catalysis and energy related applications. We illustrate how the database can be used to train AI models for material properties using the sure-independence screening and sparsifying operator (SISSO) approach.
Materials Science (cond-mat.mtrl-sci)
8 pages, 7 figures
Experimental Observation of Extremely Strong Defect-Phonon Scatterings in Semiconductor Single Crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-30 20:00 EDT
Zifeng Huang, Jianbo Liang, Yuxiang Wang, Zixuan Sun, Naoteru Shigekawa, Ming Li, Runsheng Wang, Zhe Cheng
The role of doping in tailoring thermal transport in semiconductors is critical for efficient thermal management in electronic devices. While the effects of doping have been extensively studied to tune electrical properties, its impact on thermal transport has not yet been thoroughly explored, particularly with respect to experimental investigations into exceptionally strong non-Rayleigh defect-phonon scattering phenomena. Herein, by combining the high-quality growth and advanced characterizations of cubic silicon carbide single crystals with well controlled boron doping, we experimentally observe anomalous strong defect-phonon scatterings, among the strongest reported in common semiconductors, that exceeds the predictions of the classic mass difference model by tens of times in magnitude. The measured thermal conductivity of doped 3C SiC match excellently with those predicted by first principle calculations in which resonant scattering of low frequency phonon is considered. Our findings not only shed light on the fundamental understanding of defect-phonon interactions and will also impact applications such as thermal management of electronics.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Two-dimensional non-van der Waals niobium nitride nanosheets with high-temperature two-gap superconductivity
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-30 20:00 EDT
Si-Yi Xiong, Peng Jiang, Yiming Wang, Yan-Ling Li
The exploration of the superconductivity in two-dimensional materials has garnered significant attention due to their promising low-power applications and fundamental scientific interest. Here, we report some novel stable non-van der Waals Nb$ _x$ N$ _{x+1}$ ($ x$ = 1-4) monolayers derived from the NbN bulk exfoliated along the (001) plane, as identified through first-principles calculations. Among these monolayers, Nb$ _2$ N$ _3$ , which crystallizes in the $ P \overline{6} m2$ symmetry, stands out with an exceptional superconducting transition temperature of 77.8 K, setting a new high-$ T_c$ benchmark for two-dimensional transition metal nitrides and binary compounds. Our detailed analysis reveals that the strong superconductivity in Nb$ _2$ N$ _3$ is driven by phonon modes dominated by N vibrations, with significant electron-phonon coupling contributions from N-$ p$ and Nb-$ d$ electronic states. Using the anisotropic Migdal-Eliashberg framework, we further determine the two-gap nature of the superconductivity in the Nb$ _2$ N$ _3$ monolayer, characterized by pronounced electron-phonon coupling and anisotropic energy gaps. These results advance our understanding of superconductivity in 2D transition metal nitride and highlight their potential for nanoscale superconducting applications.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
8 pages, 4 figures
Fluctuating magnetism in Zn-doped averievite with well-separated kagome layers
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-30 20:00 EDT
G. Simutis, L. Suárez-García, H. Zeroual, I. Villa, M. Georgopoulou, D. Boldrin, C. N. Wang, C. Baines, T. Shiroka, R. Khasanov, H. Luetkens, B. Fåk, Y. Sassa, M. Bartkowiak, A. S. Wills, E. Kermarrec, F. Bert, P. Mendels
Kagome lattice decorated with S=1/2 spins is one of the most discussed ways to realize a quantum spin liquid. However, all previous material realizations of this model have suffered from additional complications, ranging from additional interactions to impurity effects. Recently, a new quantum kagome system has been identified in the form of averievite Cu(5-x)ZnxV2O10(CsCl), featuring a unique double-layer spacing between the kagome planes. Using muon spin spectroscopy we show that only a complete substitution (i.e. $ x=2$ ) of interplanar copper ions leads to a quantum-disordered ground state. In contrast, the parent compound ($ x=0$ ) exhibits long-range magnetic order, with a phase transition around 24 K. Experiments performed on the partially substituted material ($ x=1$ ) show that the transformation proceeds through an intermediate disordered, partially frozen ground state, unaffected by pressures up to 23 kbar. Our study provides a microscopic view of the magnetism of the decoupling of the kagome layers and establishes the averievite as a new material platform for the experimental study of the fully-decoupled kagome layers.
Strongly Correlated Electrons (cond-mat.str-el)
Enhanced activity in layered-metal-oxide-based oxygen evolution catalysts by layer-by-layer modulation of metal ion identity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-30 20:00 EDT
Ran Ding, Daniel Maldonado-Lopez, Jacob E. Henebry, Jose Mendoza-Cortes, Michael J. Zdilla
Few-layered potassium nickel and cobalt oxides show drastic differences in catalytic activity based on metal ion preorganization. Uniform compositions $ [(\mathrm{CoO}_2/\mathrm{K})_6$ or $ (\mathrm{NiO}_2/\mathrm{K})_6]$ show limited activity, while homogenously-mixed-metal cobalt/nickel oxides $ [(\mathrm{Co}n\mathrm{Ni}{1-n}\mathrm{O}_2/\mathrm{K})_6]$ display moderate improvement. However, a layer-by-layer arrangement of cobalt and nickel oxide sheets [e.g., $ (\mathrm{CoO}_2/\mathrm{K}/\mathrm{NiO}_2/\mathrm{K})$ ] provides superior catalytic performance, reducing the oxygen evolution overpotential by more than 400 mV. Density functional theory simulations provide an illustration of the electronic properties (density of states and localization of orbitals) that promote catalysis in the layer-segregated materials over those of homogeneous composition. This study reveals that atomic preorganization of metal ions within layered catalysts plays a more crucial role than overall metal composition in enhancing catalytic efficiency for oxygen evolution.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Thermodynamic interpretation to Stochastic Fisher Information and Single-Trajectory Speed Limits
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-30 20:00 EDT
Pedro B. Melo, Fernando Iemini, Diogo O. Soares-Pinto, Sílvio M. Duarte Queirós, Welles A. M. Morgado
The Fisher information (FI) metric is a Riemannian metric that allows a geometric treatment of stochastic thermodynamics, introducing the possibility of computing thermodynamic lengths and deviations from equilibrium. At the trajectory level, a related quantity can be introduced, the stochastic Fisher information (SFI), which on average, is equivalent to the FI. In this work, we discuss two fundamental questions regarding the SFI; namely, (i) what is the thermodynamic interpretation of the SFI is and (ii) whether there are any trajectory-level thermodynamic bounds due to the SFI. We find that, contrary to previous results in the literature for the FI, the thermodynamic interpretation of the SFI depends only on the entropy produced by the system and on the thermodynamic force. Moreover, we find that the SFI allows one to derive single-trajectory speed limits, which we demonstrate to hold for a Brownian particle under a saturating drive force and a Brownian particle under a decreasing drive force. From the ensemble of single-trajectory bounds one can derive a hierarchy of average speed limits that are always less tight than the one derived from the FI. We test our results for speed limits on the adopted models and find that the hierarchy of average speed limits is respected and that the single-trajectory speed limits behave qualitatively similarly to the average and stochastic speed limits, with some trajectories achieving velocities higher than the tightest average bound whenever it does not saturate. Our results open avenues for the exploration of uncertainty relations at the trajectory level.
Statistical Mechanics (cond-mat.stat-mech)
11 pages, 7 figures
E. coli bacterium tumbling in bulk and close to surfaces: A simulation study
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-30 20:00 EDT
Pierre Martin, Tapan Chandra Adhyapak, Holger Stark
Motility is fundamental to the survival and proliferation of microorganisms. The E. coli bacterium propels itself using a bundle of rotating helical flagella. If one flagellum reverses its rotational direction, it leaves the bundle, performs a polymorphic transformation, and the bacterium tumbles. The E. coli bacterium is hydrodynamically attracted to surfaces. This prolongs its residence time, while tumbling facilitates surface detachment. We develop a model of E. coli that uses an extended Kirchhoff rod theory to implement flagellar flexibility as well as different polymorphic conformations and perform hydrodynamic simulations with the method of multiparticle collision dynamics (MPCD). To establish a reference case, we determine the distribution of tumble angles in the bulk fluid, which shows good agreement with experiments for a fixed tumble time. Increasing the hook stiffness, narrows the tumble angle distribution and reduces the flagellar dispersion during tumbling. Close to a bounding surface, the tumble angle distribution is shifted to smaller angles, while flagellar dispersion is reduced. Reorientation within the plane favors the forward direction, which might be an explanation for prolonged run times observed in experiments
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Resonant inelastic X-ray scattering investigation of Hund’s and spin-orbit coupling in $5d^2$ double perovskites
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-30 20:00 EDT
Felix Ivo Frontini, Christopher J. S. Heath, Bo Yuan, Corey M. Thompson, John Greedan, Adam J. Hauser, F. Y. Yang, Mark P. M. Dean, Mary H. Upton, Diego M. Casa, Young-June Kim
$ \mathrm{B}$ site ordered $ 5d^2$ double perovskites ($ \mathrm{A_2BB’O_6,\ B’}=5d^2)$ display a remarkable range of physical properties upon variation of the chosen $ \mathrm{B}$ and $ \mathrm{B’}$ site ions. This sensitivity to chemical substitution reflects the delicate balance and profound impact of strong electronic correlation and spin-orbit coupling in such systems. We present rhenium $ L_2$ and $ L_3$ resonant inelastic X-ray scattering (RIXS) measurements of two such physically dissimilar materials, Mott-insultating $ \mathrm{Ba_2YReO_6}$ and semiconducting $ \mathrm{Sr_2CrReO_6}$ . Despite these differences, our RIXS results reveal similar energy scales of Hund’s ($ J_H$ ) and spin-orbit coupling ($ \lambda$ ) in the two materials, with both systems firmly in the intermediate Hund’s coupling regime ($ \mathcal{O}(J_H/\lambda)\sim 1$ ). However, there are clear differences in their RIXS spectra. The conductive character of $ \mathrm{Sr_2CrReO_6}$ broadens and obfuscates the atomic transitions within an electron-hole continuum, while the insulating character of $ \mathrm{Ba_2YReO_6}$ results in sharp atomic excitations. This contrast in their RIXS spectra despite their similar energy scales reflects a difference in the itinerancy-promoting hopping integral and illustrates the impact of the local crystal environment in double perovskites. Finally, $ L_2$ and $ L_3$ edge analyses of the atomic excitations in $ \mathrm{Ba_2YReO_6}$ reveal that the energy scales of Hund’s and spin-orbit coupling are in fact inverted compared to previously reported values. We present exact diagonalization calculations of the RIXS spectra at both edges which show good agreement with our results for new energy scales of $ \lambda=0.290(5)$ eV and $ J_H=0.38(2)$ eV ($ J_H/\lambda=1.30(5)$ ).
Strongly Correlated Electrons (cond-mat.str-el)
Chemotactic aggregation dynamics of micro-swimmers in Brinkman flows
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-30 20:00 EDT
Yasser Almoteri, Enkeleida Lushi
We study through analysis and simulations of a continuum model the collective chemotactic dynamics of micro-swimmers immersed in viscous Brinkman flows. The Brinkman viscous flow approximates with a resistance or friction term the presence of inert impurities or stationary obstacles immersed in the fluid, an environment that can be regarded as a wet porous medium. Analysis of the linearized system reveals that resistance primarily affects the development of collective swimming instabilities and barely affects chemotactic instabilities. We present a parameter phase space for the distinct types of dynamics we can expect in the case of auto-chemotactic bacteria-like pusher swimmers for varying medium resistance, chemotactic response strength, and hydrodynamic coupling strength values. Simulations of the full nonlinear system show that resistance impacts the collective dynamics for each of these states because it inhibits the hydrodynamic interactions and the emergence of the collective swimmer. Surprisingly, and not expected from the linear analysis predictions, we find that resistance also hampers the chemotactic aggregation of the swimmers because it impedes their ability to navigate efficiently and collectively towards chemical cues and assemble into clusters. We show simulations of the complex system for parameters sets from each of the phase-space regions and quantify the observed behavior. Lastly, we discuss the experimental values of the parameters and discuss possible future experimental realizations of this system.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph), Fluid Dynamics (physics.flu-dyn)
Interfacial Behavior from the Atomic Blueprint: Machine Learning-Guided Design of Spatially Functionalized a-SiO2 Surfaces
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-30 20:00 EDT
Evgenii Strugovshchikov, Viktor Mandrolko, Dominika Lesnicki, Mariachiara Pastore, Laurent Chaput, Mykola Isaiev
Precise control over surface chemistry is essential for tuning interfacial behavior in technologies ranging from catalysis and protective coatings to energy conversion systems. Although chemical functionalization of alpha-quartz (alpha-SiO2) with hydroxyl (OH) and methyl (CH3) groups has been extensively studied, the impact of their spatial distribution at the atomic scale remains largely uncharted. In this work, we integrate density functional theory (DFT), ab initio molecular dynamics (AIMD), and on-the-fly machine-learned force fields (MLFFs) to systematically investigate how different arrangements of OH/CH3 groups modulate surface properties. Our results reveal that spatial patterning governs the formation of hydrogen-bonding networks, alters vibrational signatures, and has a significant influence on the thermodynamic stability of the functionalized surfaces. The MLFF framework enables high-fidelity simulations at unprecedented scales, bridging the gap between quantum accuracy and statistical sampling. By uncovering structure-property relationships inaccessible to conventional approaches, this study establishes spatial arrangement of functionalized groups as a critical and tunable design axis, paving the way for the predictive engineering of silica-based materials with optimized interfacial performance.
Materials Science (cond-mat.mtrl-sci)
A Quieter State of Charge – Ultra-Low-Noise Collective Current in Charge-Density-Wave Nanowires
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-30 20:00 EDT
Subhajit Ghosh, Nicholas Sesing, Tina Salguero, Sergey Rumyantsev, Roger K. Lake, Alexander A. Balandin
In quasi-one-dimensional (quasi-1D) charge-density-wave (CDW) systems, electric current comprises normal electrons and a collective, electron-lattice condensate current associated with CDW sliding. While achieving the dissipation-less Frohlich current of the sliding condensate is impossible in real materials, one can imagine an important related target, namely reaching the electron transport regime where electronic noise is inhibited due to the collective, strongly-correlated nature of the electron-lattice condensate current. Here we report that in nanowires of the fully-gapped CDW material (TaSe4)2I, low-frequency electronic noise is suppressed below the limit of thermalized charge carriers in passive resistors. When the current is dominated by the sliding Frohlich condensate, the normalized noise spectral density decreases linearly with current – a striking departure from the constant value observed in conventional conductors. This discovery signals intrinsically lower current fluctuations within a correlated transport regime. The dominant noise source due to fluctuations in the CDW depinning threshold is extrinsic and caused by lattice imperfections that locally pin the condensate. Once the bias voltage is well past threshold and the sliding mode is established, the normalized noise drops below the noise of normal electrons. No residual minimum noise level is observed for the current of the condensate. Since flicker noise limits phase stability in communication systems, reduces the sensitivity and selectivity of sensors, and degrades coherence in quantum devices, our discovery introduces a fundamentally new strategy for achieving ultra-low-noise performance in nanoscale and quantum electronics using strongly correlated materials.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
29 pages; 12 pages
Soft-X-ray momentum microscopy of nonlinear magnon interactions below 100-nm wavelength
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Steffen Wittrock, Christopher Klose, Salvatore Perna, Korbinian Baumgaertl, Andrea Mucchietto, Michael Schneider, Josefin Fuchs, Victor Deinhart, Tamer Karaman, Dirk Grundler, Stefan Eisebitt, Bastian Pfau, Daniel Schick
Magnons represent quantised collective motions of long-range ordered spins. For wavelength below 100 nm, exchange interactions dominate their physics, which gives rise to a so far unexplored regime of nonlinearities and couplings between magnons and other quasiparticles. Besides their selective excitation, also the detection of such short-wavelength spin waves remains a challenge of current research and technology. Here, we probe the amplitude and wave vector of magnons by means of quasi-elastic resonant soft-X-ray scattering. This Magnon Momentum Microscopy (MMM) can access magnons directly in momentum space with remarkable sensitivity and high photon efficiency up to THz frequencies and down to few-nanometre wavelengths. The two-dimensional information obtained by this light-scattering-based technique is especially valuable for studying the nonlinear interactions of exchange-dominated magnons within technologically relevant thin-film samples. In doing so, we uncover a rich variety of deeply nonlinear magnon interactions, highlighting their potential for applications in novel computing schemes. With its intrinsic element-selectivity and ability to probe also buried layers, soft-X-ray MMM has the potential to establish itself as an advanced tool for ultrabroadband studies of short-wavelength magnonics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Ancillary files include videos presenting MMM images during (a) a frequency sweep and (b) a power sweep
Optical Activity of Group III-V Quantum Dots Directly Embedded in Silicon
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Optically active III-V group semiconductor quantum dots (QDs) are the leading element of the upcoming safe quantum communication. However, the entire electronic and IT infrastructure relies on silicon-based devices, with silicon also providing a natural platform for photonic integration. Combining semiconductor optics with silicon electronics is thus a major technological challenge. This obstacle cannot be directly solved because silicon is optically inactive. Interfacing III-V quantum dots with silicon is thus a sought-after solution. A radical approach is to embed III-V material grains directly into silicon. The first realization of such technology was developed, and it gave InAs and core-shell InAs/GaAs QDs embedded in Si with bright and narrow single-QD emission lines. No theory has been given, though, and, as we show here, it is not even obvious if and how such QDs can be optically active. We first use general arguments, also supported by atomistic calculations, that InAs/Si QDs cannot confine both carrier types unless the structural strain is mostly relaxed, meaning many defects at the interface. This explains the lack of light emission from those dots. Then we show that the InAs/GaAs/Si QDs can confine both carrier types. Their electron states are, however, highly influenced by $ k$ -space valley mixing, which impacts emission spectra and deteriorates optical properties. We propose to overcome this by adding an additional wider-bandgap material layer.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
6 pages, 4 figures
Modification of the scattering mechanisms in bilayer graphene in proximity to a molecular thin film probed in the mesoscopic regime
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-30 20:00 EDT
Anise Mansour, Deanna Diaz, Movindu Kawshan Dissanayake, Erin Henkhaus, Jungyoun Cho, Vinh Tran, Francisco Ramirez, Eric Corona-Oceguera, Joshua Luna, Kenta Kodama, Yueyun Chen, Ho Chan, Jacob Weber, Blake Koford, Patrick Barfield, Maya Martinez, Kenji Watanabe, Takashi Taniguchi, B. C. Regan, Matthew Mecklenburg, Thomas Gredig, Claudia Ojeda-Aristizabal
Quantum coherent effects can be probed in multilayer graphene through electronic transport measurements at low temperatures. In particular, bilayer graphene is known to be susceptible to quantum interference corrections of the conductivity, presenting weak localization at all electronic densities, and dependent on different scattering mechanisms as well as on the trigonal warping of the electron dispersion near the K and K’ valleys. Proximity effects with a molecular thin film influence these scattering mechanisms, which can be quantified through the known theory of magnetoconductance for bilayer graphene. Here, we present weak localization measurements in a copper-phthalocyanine / bilayer graphene / h-BN heterostructure that suggest an important suppression of trigonal warping effects in bilayer graphene (BLG), restoring the manifestation of the chirality of the charge carriers in the localization properties of BLG. Additionally, we observe a charge transfer of 3.6$ \times$ 10$ ^{12}$ cm$ ^{-2}$ from the BLG to the molecules, as well as a very small degradation of the mobility of the BLG/h-BN heterostructure upon the deposition of copper phthalocyanine (CuPc). The molecular arrangement of the CuPc thin film is characterized in a control sample through transmission electron microscopy, that we relate to the electronic transport results.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 9 figures