CMP Journal 2025-08-27
Statistics
Nature: 23
Nature Materials: 1
Nature Physics: 1
Physical Review Letters: 16
Physical Review X: 2
arXiv: 75
Nature
Ultrabroadband on-chip photonics for full-spectrum wireless communications
Original Paper | Electrical and electronic engineering | 2025-08-26 20:00 EDT
Zihan Tao, Haoyu Wang, Hanke Feng, Yijun Guo, Bitao Shen, Dan Sun, Yuansheng Tao, Changhao Han, Yandong He, John E. Bowers, Haowen Shu, Cheng Wang, Xingjun Wang
The forthcoming sixth-generation and beyond wireless networks are poised to operate across an expansive frequency range–from microwave, millimetre wave to terahertz bands–to support ubiquitous connectivity in diverse application scenarios1,2,3. This necessitates a one-size-fits-all hardware solution that can be adaptively reconfigured within this wide spectrum to support full-band coverage and dynamic spectrum management4. However, existing electrical or photonic-assisted solutions face a lot of challenges in meeting this demand because of the limited bandwidths of the devices and the intrinsically rigid nature of system architectures5. Here we demonstrate adaptive wireless communications over an unprecedented frequency range spanning over 100 GHz, driven by a thin-film lithium niobate (TFLN) photonic wireless system. Leveraging the Pockels effect and scalability of the TFLN platform, we achieve monolithic integration of essential functional elements, including baseband modulation, broadband wireless-photonic conversion and reconfigurable carrier and local signal generation. Powered by broadband tunable optoelectronic oscillators, our signal sources operate across a record-wide frequency range from 0.5 GHz to 115 GHz with high-frequency stability and consistent coherence. Based on the broadband and reconfigurable integrated photonic solution, we realize full-link wireless communication across nine consecutive bands, achieving record lane speeds of up to 100 Gbps. The real-time reconfigurability further enables adaptive frequency allocation, a crucial ability to ensure enhanced reliability in complex spectrum environments. Our proposed system represents a marked step towards future full-spectrum and omni-scenario wireless networks.
Electrical and electronic engineering, Integrated optics, Optoelectronic devices and components
Thioester-mediated RNA aminoacylation and peptidyl-RNA synthesis in water
Original Paper | Nucleic acids | 2025-08-26 20:00 EDT
Jyoti Singh, Benjamin Thoma, Daniel Whitaker, Max Satterly Webley, Yuan Yao, Matthew W. Powner
To orchestrate ribosomal peptide synthesis, transfer RNAs (tRNAs) must be aminoacylated, with activated amino acids, at their 2’,3’-diol moiety1,2, and so the selective aminoacylation of RNA in water is a key challenge that must be resolved to explain the origin of protein biosynthesis. So far, there have been no chemical methods to effectively and selectively aminoacylate RNA-2’,3’-diols with the breadth of proteinogenic amino acids in water3,4,5. Here we demonstrate that (biological) aminoacyl-thiols (1) react selectively with RNA diols over amine nucleophiles, promoting aminoacylation over adventitious (non-coded) peptide bond formation. Broad side-chain scope is demonstrated, including Ala, Arg, Asp, Glu, Gln, Gly, His, Leu, Lys, Met, Phe, Pro, Ser and Val, and Arg aminoacylation is enhanced by unprecedented side-chain nucleophilic catalysis. Duplex formation directs chemoselective 2’,3’-aminoacylation of RNA. We demonstrate that prebiotic nitriles, N-carboxyanhydrides and amino acid anhydrides, as well as biological aminoacyl-adenylates, all react with thiols (including coenzymes A and M) to selectively yield aminoacyl-thiols (1) in water. Finally, we demonstrate that the switch from thioester to thioacid activation inverts diol/amine selectivity, promoting peptide synthesis in excellent yield. Two-step, one-pot, chemically controlled formation of peptidyl-RNA is observed in water at neutral pH. Our results indicate an important role for thiol cofactors in RNA aminoacylation before the evolution of proteinaceous synthetase enzymes.
Nucleic acids, Organic chemistry, Chemical origin of life
Mapping urban gullies in the Democratic Republic of the Congo
Original Paper | Climate-change impacts | 2025-08-26 20:00 EDT
Guy Ilombe Mawe, Eric Lutete Landu, Elise Dujardin, Fils Makanzu Imwangana, Charles Bielders, Aurélia Hubert, Caroline Michellier, Charles Nzolang, Jean Poesen, Olivier Dewitte, Matthias Vanmaercke
Large urban gullies cause damage in many tropical cities across the Global South1,2. They can result from inappropriate urban planning and insufficient infrastructure to safely store and evacuate rainfall in environments that are already highly sensitive to soil erosion1,3,4. Although they can cause large destruction and societal impacts such as population displacement1,2,5, the magnitude of this geo-hydrological hazard remains poorly documented and understood6,7. Here we provide an assessment of the extent and impact of urban gullies at the scale of the Democratic Republic of the Congo (DRC). Through mapping, we identify 2,922 urban gullies across 26 cities. By combining their formation and growth rates with population density data8, we estimate that around 118,600 people (uncertainty range: ± 44,400 people) have been displaced by urban gullies over the period 2004-2023. We find that average displacement rates increased from about 4,650 persons yr-1 (pre-2020) to about 12,200 persons yr-1 (post-2020). Between 2010 and 2023, the number of people living in the potential expansion zone of urban gullies doubled from 1.6 (±0.6) to 3.2 (±1.3) million, with more likely to be exposed due to urban sprawl9,10 and climate change11. We suggest that there is a need for tools and strategies to prevent and mitigate this hazard.
Climate-change impacts, Environmental impact, Natural hazards, Sustainability
Rate and noise in human amygdala drive increased exploration in aversive learning
Original Paper | Amygdala | 2025-08-26 20:00 EDT
Tamar Reitich-Stolero, Kristoffer C. Aberg, Dean Halperin, Carmel Ariel, Genela Morris, Lilach Goldstein, Firas Fahoum, Ido Strauss, Rony Paz
To cope in uncertain environments, animals must balance their actions between using current resources and searching for new ones1. This exploration-exploitation dilemma has been studied extensively in paradigms involving positive outcomes, and neural correlates have been identified in frontal cortices and subcortical structures2,3,4,5,6,7,8,9,10,11, including the amygdala12. Importantly, exploration is just as essential for survival or well-being when trying to avoid negative outcomes, yet we do not know whether the single-neuron mechanisms that drive exploration are shared across positive and negative environments. Here we examined the dynamics of exploration when human participants engaged in a probabilistic learning task with intermixed loss and gain trials, while simultaneously recording single-neuron activity. We show that neurons of the amygdala and temporal cortex modulate their activity before a decision to explore in both loss and gain. Moreover, we find that humans exhibit more exploration when trying to avoid losses, and that an increase in the levels of noise in amygdala neurons contributes to this behaviour. Overall, we report that human exploration is driven by two distinct neural mechanisms, a valence-independent rate signal and a valence-dependent global noise signal. The results suggest a link between the heightened amygdala activity observed in mood disorders13,14 and higher exploration rates15,16,17 that underlie maladaptive and even pathological behaviours.
Amygdala, Learning and memory
Crystal structures of agonist-bound human cannabinoid receptor CB1
Original Paper | Medicinal chemistry | 2025-08-26 20:00 EDT
Tian Hua, Kiran Vemuri, Spyros P. Nikas, Yiran Wu, Lu Qu, Mengchen Pu, Anisha Korde, Shan Jiang, Jo-Hao Ho, Gye Won Han, Kang Ding, Xuanxuan Li, Haiguang Liu, Michael A. Hanson, Suwen Zhao, Laura M. Bohn, Alexandros Makriyannis, Raymond C. Stevens, Zhi-Jie Liu
Cannabinoid receptor 1 (CB1) is the primary target of the partial agonist Δ9-tetrahydrocannabinol (Δ9-THC), the psychoactive constituent of marijuana1. Here we report two agonist-bound crystal structures of human CB1 in complex with a tetrahydrocannabinol (AM11542) and a hexahydrocannabinol (AM841). The two CB1-agonist complexes reveal important conformational changes in the overall structure relative to the antagonist-bound state2, including a 53% reduction in the volume of the ligand-binding pocket and an increase in the surface area of the G protein-binding region. Furthermore, a twin toggle switch of Phe2003.36 and Trp3566.48 (where the superscripts denote Ballesteros-Weinstein numbering3) is experimentally observed and seems to be essential for receptor activation. The structures reveal important insights into the activation mechanism of CB1 and provide a molecular basis for predicting the binding modes of Δ9-THC, and endogenous and synthetic cannabinoids. The plasticity of the binding pocket of CB1 seems to be a common feature among certain class A G protein-coupled receptors. These findings should inspire the design of chemically diverse ligands with distinct pharmacological properties.
Medicinal chemistry, X-ray crystallography
Maternal stress triggers early-life eczema through fetal mast cell programming
Original Paper | Mast cells | 2025-08-26 20:00 EDT
Nadine Serhan, Nasser S. Abdullah, Nadine Gheziel, Alexia Loste, Rüçhan Ekren, Elodie Labit, Anne-Alicia Gonzalez, Giulia Oliva, Pauline Tarot, Camille Petitfils, Gaëlle Payros, Paolo D’Avino, Allison Voisin, Holly Freya Grace Tinsley, Rebecca Gentek, Carole Brosseau, Marie Bodinier, Laurent Reber, Pierre Val, Cezmi A. Akdis, Yasutaka Mitamura, Anand Kumar Andiappan, Jerry Kok Yen Chan, Florent Ginhoux, Amaury François, Nicolas Cénac, Lilian Basso, Nicolas Gaudenzio
Prenatal stress (PS) is a repeated exposure to aversive situations during pregnancy, including high emotional strain, which is suspected to affect homeostatic systems in infants. Paediatric eczema develops quickly after birth at flexural sites subjected to continuous mechanical constraints1,2. Although epidemiological studies have suggested an association between PS and a higher risk of eczema in children3,4,5,6, no causative biological link has yet been identified. Here we show that eczema at birth originates from molecular dysregulations of neuroimmune circuits in utero, triggered by fluctuations in the maternal hypothalamic-pituitary-adrenal axis. We found that offspring of stressed pregnant dams have dysregulated mast cells and skin-projecting neurons and quickly develop eczema in response to harmless mechanical friction. We demonstrated that PS transiently modulates amniotic fluid corticosterone concentrations, which directly alters the activation program of skin mast cells expressing the glucocorticoid receptor Nr3c1 and the adjacent sensory neurons conveying mechanosensation. Therapeutic normalization of maternal corticosterone concentrations or genetic depletion of Mcpt5+ mast cells during stressed gestation prevents fetal immune dysregulation and protects against eczema development after birth. Our findings support a new model in which early-onset paediatric eczema originates from dysregulations in the fetal immune system, caused by fluctuations in maternal glucocorticoids induced by stress.
Mast cells, Neuroimmunology
Electrically driven lasing from a dual-cavity perovskite device
Original Paper | Electronics, photonics and device physics | 2025-08-26 20:00 EDT
Chen Zou, Zhixiang Ren, Kangshuo Hui, Zixiang Wang, Yangning Fan, Yichen Yang, Bo Yuan, Baodan Zhao, Dawei Di
Solution-processed semiconductor lasers promise lightweight, wearable and scalable optoelectronic applications. Among the gain media for solution-processed lasers, metal halide perovskites stand out as an exceptional class because of their ability to achieve wavelength-adjustable, low-threshold lasing under optical pumping1,2,3,4,5,6,7,8. Despite the progress in this field, electrically driven lasing from perovskite semiconductors remains a critical challenge. Here we demonstrate an electrically driven perovskite laser, constructed by vertically integrating a low-threshold single-crystal perovskite microcavity sub-unit with a high-power microcavity perovskite LED (PeLED) sub-unit. Under pulsed electrical excitation, the dual-cavity perovskite device shows a minimum lasing threshold of 92 A cm-2 (average threshold: 129 A cm-2, at about 22 °C, in air), which is an order of magnitude lower than that of state-of-the-art electrically driven organic lasers9,10. Key to this demonstration is the integrated dual-cavity device architecture, which allows the microcavity PeLED sub-unit to deliver directional emission into the single-crystal perovskite microcavity sub-unit (at a coupling efficiency of about 82.7%) to establish the lasing action. An operational half-life (T50) of 1.8 h (6.4 × 104 voltage pulses at 10 Hz) is achieved, outperforming the stability of electrically pumped organic lasers9,10. The dual-cavity perovskite laser can be rapidly modulated at a bandwidth of 36.2 MHz, indicating its potential for data transmission and computational applications.
Electronics, photonics and device physics, Lasers, LEDs and light sources, Materials for devices, Nanoscale devices, Optical materials
Mechanical confinement governs phenotypic plasticity in melanoma
Original Paper | Cancer imaging | 2025-08-26 20:00 EDT
Miranda V. Hunter, Eshita Joshi, Sydney Bowker, Emily Montal, Yilun Ma, Young Hun Kim, Zhifan Yang, Laura Tuffery, Zhuoning Li, Eric Rosiek, Alexander Browning, Reuben Moncada, Itai Yanai, Helen Byrne, Mara Monetti, Elisa de Stanchina, Pierre-Jacques Hamard, Richard P. Koche, Richard M. White
Phenotype switching is a form of cellular plasticity in which cancer cells reversibly move between two opposite extremes: proliferative versus invasive states1,2. Although it has long been hypothesized that such switching is triggered by external cues, the identity of these cues remains unclear. Here we demonstrate that mechanical confinement mediates phenotype switching through chromatin remodelling. Using a zebrafish model of melanoma coupled with human samples, we profiled tumour cells at the interface between the tumour and surrounding microenvironment. Morphological analysis of interface cells showed elliptical nuclei, suggestive of mechanical confinement by the adjacent tissue. Spatial and single-cell transcriptomics demonstrated that interface cells adopted a gene program of neuronal invasion, including the acquisition of an acetylated tubulin cage that protects the nucleus during migration. We identified the DNA-bending protein HMGB2 as a confinement-induced mediator of the neuronal state. HMGB2 is upregulated in confined cells, and quantitative modelling revealed that confinement prolongs the contact time between HMGB2 and chromatin, leading to changes in chromatin configuration that favour the neuronal phenotype. Genetic disruption of HMGB2 showed that it regulates the trade-off between proliferative and invasive states, in which confined HMGB2high tumour cells are less proliferative but more drug-resistant. Our results implicate the mechanical microenvironment as a mechanism that drives phenotype switching in melanoma.
Cancer imaging, Cancer microenvironment, Cancer models, Melanoma, Tumour heterogeneity
Neural networks of the mouse visceromotor cortex
Original Paper | Network models | 2025-08-26 20:00 EDT
Houri Hintiryan, Muye Zhu, Pingping Zhao, Mingmin Zhang, Joshua Barry, Sumit Nanda, Mitchell Rudd, Angela Wong, Samara Miller, Lin Gou, Jinxing Wei, Brian Zingg, Jiandong Sun, Adriana Gutierrez, Hyun-Seung Mun, Yeji E. Han, Ian Bowman, Luis Garcia, Darrick Lo, Tyler Boesen, Chunru Cao, Qiuying Zhao, Nicholas N. Foster, Keivan Moradi, Seita Yamashita, Christian Estrada, Aishwarya Dev, Jennifer Gonzalez, Hanpeng Xu, Gavin Yang, Chang Sin Park, X. William Yang, Michael S. Levine, Li I. Zhang, Paul Micevych, Carlos Cepeda, Peyman Golshani, Weizhe Hong, Hong-Wei Dong
The medial prefrontal cortex (MPF) regulates autonomic and neuroendocrine responses to stress1,2 and coordinates goal-directed behaviours such as attention, decision-making and social interactions3,4,5,6,7,8. However, the underlying mechanisms remain unclear due to incomplete circuit-level MPF characterization7. Here, using integrated neuroanatomical, physiological and behavioural approaches, we construct a comprehensive wiring diagram of the MPF, focused on the dorsal peduncular area (DP)–a poorly understood prefrontal area. We identify its deep (DPd) and superficial (DPs) layers, along with the infralimbic area, as major components of the visceromotor cortex that directly project to hypothalamic and brainstem structures to govern neuroendocrine, sympathetic and parasympathetic output. Notably, the DP functions as a network hub integrating diverse cortical inputs and modulating goal-directed behaviour through a largely unidirectional cortical information flow. On the basis of the mesoscale MPF connectome, we propose a unified network model in which distinct MPF areas orchestrate physiological and behavioural responses to internal and external stimuli.
Network models, Neural circuits
Two-billion-year transitional oxygenation of the Earth’s surface
Original Paper | Atmospheric chemistry | 2025-08-26 20:00 EDT
Haiyang Wang, Chao Li, Yongbo Peng, Junpeng Zhang, Meng Cheng, Xiaobin Cao, Wenkun Qie, Zihu Zhang, Matthew S. Dodd, Mingcai Hou, Malcolm Wallace, Ashleigh v. S. Hood, Timothy W. Lyons, Huiming Bao
Earth’s surface underwent stepwise oxygenation before persistently reaching modern levels late in its history1,2,3,4,5, but the details of this transition remain unclear5,6,7,8,9,10,11,12,13,14,15,16. Here we present a high-resolution 2.5-Gyr record of mass-independent oxygen isotopes in sedimentary sulfate (Δ’17Osulfate), a proxy linked to the atmospheric partial pressure of O2 (({p}{ { {\rm{O}}}{2}}))17,18,19. This record, together with existing sedimentary Δ33S data20,21,22, demonstrates a 2-Gyr transition characterized by generally low, fluctuating ({p}{ { {\rm{O}}}{2}}) between an O2-free state before 2.4 billion years ago (Ga) and a modern ({p}{ { {\rm{O}}}{2}}) state after 0.41 Ga, with relatively elevated levels after 1.0 Ga. Our data also show coupled declines in Δ’17Osulfate and sulfate-δ34S during major negative carbonate-δ13C excursions in the Neoproterozoic. Quantitative biogeochemical modelling indicates that these isotopic couplings reflect the increasing ({p}{ { {\rm{O}}}{2}}), which may have driven episodic ocean oxygenation through an increased atmospheric O2 influx. This process intensified the oxidation of marine organics and reduced-sulfur species, while triggering temporary ({p}{ { {\rm{O}}}{2}}) drawdowns as negative feedback15. These findings support a dynamic, lengthy co-oxygenation history for the atmosphere and oceans–marked by long-term positive coupling and short-term negative feedbacks–offering a coherent explanation for the anomalous Neoproterozoic carbon cycles23,24 and the protracted, episodic rise of complex life25,26,27.
Atmospheric chemistry, Carbon cycle, Element cycles, Geochemistry, Marine chemistry
One-shot design of functional protein binders with BindCraft
Original Paper | Biochemistry | 2025-08-26 20:00 EDT
Martin Pacesa, Lennart Nickel, Christian Schellhaas, Joseph Schmidt, Ekaterina Pyatova, Lucas Kissling, Patrick Barendse, Jagrity Choudhury, Srajan Kapoor, Ana Alcaraz-Serna, Yehlin Cho, Kourosh H. Ghamary, Laura Vinué, Brahm J. Yachnin, Andrew M. Wollacott, Stephen Buckley, Adrie H. Westphal, Simon Lindhoud, Sandrine Georgeon, Casper A. Goverde, Georgios N. Hatzopoulos, Pierre Gönczy, Yannick D. Muller, Gerald Schwank, Daan C. Swarts, Alex J. Vecchio, Bernard L. Schneider, Sergey Ovchinnikov, Bruno E. Correia
Protein-protein interactions are at the core of all key biological processes. However, the complexity of the structural features that determine protein-protein interactions makes their design challenging. Here we present BindCraft, an open-source and automated pipeline for de novo protein binder design with experimental success rates of 10-100%. BindCraft leverages the weights of AlphaFold2 (ref. 1) to generate binders with nanomolar affinity without the need for high-throughput screening or experimental optimization, even in the absence of known binding sites. We successfully designed binders against a diverse set of challenging targets, including cell-surface receptors, common allergens, de novo designed proteins and multi-domain nucleases, such as CRISPR-Cas9. We showcase the functional and therapeutic potential of designed binders by reducing IgE binding to birch allergen in patient-derived samples, modulating Cas9 gene editing activity and reducing the cytotoxicity of a foodborne bacterial enterotoxin. Last, we use cell-surface-receptor-specific binders to redirect adeno-associated virus capsids for targeted gene delivery. This work represents a significant advancement towards a ‘one design-one binder’ approach in computational design, with immense potential in therapeutics, diagnostics and biotechnology.
Biochemistry, Protein design
Topological prethermal strong zero modes on superconducting processors
Original Paper | Quantum physics | 2025-08-26 20:00 EDT
Feitong Jin, Si Jiang, Xuhao Zhu, Zehang Bao, Fanhao Shen, Ke Wang, Zitian Zhu, Shibo Xu, Zixuan Song, Jiachen Chen, Ziqi Tan, Yaozu Wu, Chuanyu Zhang, Yu Gao, Ning Wang, Yiren Zou, Aosai Zhang, Tingting Li, Jiarun Zhong, Zhengyi Cui, Yihang Han, Yiyang He, Han Wang, Jia-Nan Yang, Yanzhe Wang, Jiayuan Shen, Gongyu Liu, Jinfeng Deng, Hang Dong, Pengfei Zhang, Weikang Li, Dong Yuan, Zhide Lu, Zheng-Zhi Sun, Hekang Li, Junxiang Zhang, Chao Song, Zhen Wang, Qiujiang Guo, Francisco Machado, Jack Kemp, Thomas Iadecola, Norman Y. Yao, H. Wang, Dong-Ling Deng
Symmetry-protected topological phases1,2,3,4 cannot be described by any local order parameter and are beyond the conventional symmetry-breaking model5. They are characterized by topological boundary modes that remain stable under symmetry respecting perturbations1,2,3,4,6,7,8. In clean, gapped systems without disorder, the stability of these edge modes is restricted to the zero-temperature manifold; at finite temperatures, interactions with mobile thermal excitations lead to their decay9,10,11. Here we report the observation of a distinct type of topological edge mode12,13,14, which is protected by emergent symmetries and persists across the entire spectrum, in an array of 100 programmable superconducting qubits. Through digital quantum simulation of a one-dimensional disorder-free stabilizer Hamiltonian, we observe robust long-lived topological edge modes over up to 30 cycles for a wide range of initial states. We show that the interaction between these edge modes and bulk excitations can be suppressed by dimerizing the stabilizer strength, leading to an emergent U(1) × U(1) symmetry in the prethermal regime of the system. Furthermore, we exploit these topological edge modes as logical qubits and prepare a logical Bell state, which exhibits persistent coherence, despite the system being disorder-free and at finite temperature. Our results establish a viable digital simulation approach15,16,17,18 to experimentally study topological matter at finite temperature and demonstrate a potential route to construct long-lived, robust boundary qubits in disorder-free systems.
Quantum physics, Topological matter
Microbial iron oxide respiration coupled to sulfide oxidation
Original Paper | Element cycles | 2025-08-26 20:00 EDT
Song-Can Chen, Xiao-Min Li, Nicola Battisti, Guoqing Guan, Maria A. Montoya, Jay Osvatic, Petra Pjevac, Shaul Pollak, Andreas Richter, Arno Schintlmeister, Wolfgang Wanek, Marc Mussmann, Alexander Loy
Microorganisms have driven Earth’s sulfur cycle since the emergence of life1,2,3,4,5,6, yet the sulfur-cycling capacities of microorganisms and their integration with other element cycles remain incompletely understood. One such uncharacterized metabolism is the coupling of sulfide oxidation with iron(iii) oxide reduction, a ubiquitous environmental process hitherto considered to be strictly abiotic7,8. Here we present a comprehensive genomic analysis of sulfur metabolism across prokaryotes, and reveal bacteria that are capable of oxidizing sulfide using extracellular solid phase iron(iii). Based on a phylogenetic framework of over hundred genes involved in dissimilatory transformation of sulfur compounds, we recorded sulfur-cycling capacity in most bacterial and archaeal phyla. Metabolic reconstructions predicted co-occurrence of sulfur compound oxidation and iron(iii) oxide respiration in diverse members of 37 prokaryotic phyla. Physiological and transcriptomic evidence demonstrated that a cultivated representative, Desulfurivibrio alkaliphilus, grows autotrophically by oxidizing dissolved sulfide or iron monosulfide (FeS) to sulfate with ferrihydrite as an extracellular iron(iii) electron acceptor. The biological process outpaced the abiotic process at environmentally relevant sulfide concentrations. These findings expand the known diversity of sulfur-cycling microorganisms and unveil a biological mechanism that links sulfur and iron cycling in anoxic environments, thus highlighting the fundamental role of microorganisms in global element cycles.
Element cycles, Environmental microbiology
Attosecond control and measurement of chiral photoionization dynamics
Original Paper | Atomic and molecular interactions with photons | 2025-08-26 20:00 EDT
Meng Han, Jia-Bao Ji, Alexander Blech, R. Esteban Goetz, Corbin Allison, Loren Greenman, Christiane P. Koch, Hans Jakob Wörner
Many chirality-sensitive light-matter interactions are governed by chiral electron dynamics. Therefore, the development of advanced technologies making use of chiral phenomena would critically benefit from measuring and controlling chiral electron dynamics on their natural attosecond timescales. Such endeavours have so far been hampered by the lack of characterized circularly polarized attosecond pulses, an obstacle that has recently been overcome1,2. Here we introduce chiroptical spectroscopy with attosecond pulses and demonstrate attosecond coherent control over photoelectron circular dichroism (PECD)3,4, as well as the measurement of chiral asymmetries in the forward-backward and angle-resolved photoionization delays of chiral molecules. We show that co-rotating attosecond and near-infrared (IR) pulses can nearly double the PECD and even change its sign compared with single-photon ionization. We demonstrate that chiral photoionization delays depend on both polar and azimuthal angles of photoemission in the light-propagation frame, requiring 3D momentum resolution. We measure forward-backward chiral-sensitive delays of up to 60 as and polar-angle-resolved photoionization delays of up to 240 as, which include an asymmetry of about 60 as originating from chirality in the continuum-continuum transitions. Attosecond chiroptical spectroscopy opens the door to quantitatively understanding and controlling the dynamics of chiral molecules on the electronic timescale.
Atomic and molecular interactions with photons, Chemical physics, Circular dichroism
Global phenology maps reveal the drivers and effects of seasonal asynchrony
Original Paper | Biogeography | 2025-08-26 20:00 EDT
Drew E. Terasaki Hart, Thảo-Nguyên Bùi, Lauren Di Maggio, Ian J. Wang
Terrestrial plant communities show great variation in their annual rhythms of growth, or seasonal phenology1,2. The geographical patterns resulting from this variation, known as land surface phenology (LSP)3, contain valuable information for the study of ecosystem function4,5, plant ecophysiology6,7,8, landscape ecology9,10 and evolutionary biogeography11,12,13. Yet globally consistent LSP mapping has been hampered by methods that struggle to represent the full range of seasonal phenologies occurring across terrestrial biomes14, especially the subtle and complex phenologies of many arid and tropical ecosystems1,15,16. Here, using a data-driven analysis of satellite imagery to map LSP worldwide, we provide insights into Earth’s phenological diversity, documenting both intercontinental convergence between similar climates and regional heterogeneity associated with topoclimate, ecohydrology and vegetation structure. We then map spatial phenological asynchrony and the modes of asynchronous seasonality that control it, identifying hotspots of asynchrony in tropical mountains and Mediterranean climate regions and reporting evidence for the hypothesis that climatically similar sites exhibit greater phenological asynchrony within the tropics. Finally, we find that our global LSP map predicts complex geographical discontinuities in flowering phenology, genetic divergence and even harvest seasonality across a range of taxa, establishing remote sensing as a crucial tool for understanding the ecological and evolutionary consequences of allochrony by allopatry.
Biogeography, Evolutionary ecology, Phenology, Population genetics, Tropical ecology
Haematopoietic stem cell number is not solely defined by niche availability
Original Paper | Haematopoietic stem cells | 2025-08-26 20:00 EDT
Shoichiro Takeishi, Tony Marchand, Wade R. Koba, Daniel K. Borger, Chunliang Xu, Chandan Guha, Aviv Bergman, Paul S. Frenette, Kira Gritsman, Ulrich Steidl
Haematopoietic stem cells (HSCs) reside in specialized microenvironments, referred to as niches, and the classical model suggests that HSC numbers are predominantly determined by the niche size1,2,3,4,5. However, the vast excess of niche cells relative to HSCs challenges this perspective. To rigorously define the role of niche size in regulating HSC numbers, we developed a femur-transplantation system, enabling us to increase available HSC niches. Notably, the addition of niches did not alter the total HSC numbers in the body, suggesting the presence of a systemic mechanism that limits HSC numbers. Additionally, HSC numbers in transplanted wild-type femurs did not exceed physiological levels when HSCs were mobilized from defective endogenous niches to the periphery, indicating that HSC numbers are constrained at the local level as well. The notion of dual restrictions at systemic and local levels was further supported by other experimental approaches, including parabiosis and non-conditioned transfer of HSCs after bone transplantation. Moreover, we found that thrombopoietin has a pivotal role in determining the total number of HSCs in the body, even in the context of increased niche availability. Our study redefines key principles underlying HSC number regulation, providing insights into this critical biological process.
Haematopoietic stem cells, Stem cells
Dual-scale chemical ordering for cryogenic properties in CoNiV-based alloys
Original Paper | Mechanical engineering | 2025-08-26 20:00 EDT
Tiwen Lu, Binhan Sun, Yue Li, Sheng Dai, Ning Yao, Wenbo Li, Xizhen Dong, Xiyu Chen, Jiacheng Niu, Fan Ye, Alisson Kwiatkowski da Silva, Shuya Zhu, Yu Xie, Xiaofeng Yang, Sihao Deng, Jianping Tan, Zhiming Li, Dirk Ponge, Lunhua He, Xian-Cheng Zhang, Dierk Raabe, Shan-Tung Tu
The mechanical properties of metallic materials often degrade under harsh cryogenic conditions, posing challenges for low-temperature infrastructures1. Here we introduce a dual-scale atomic-ordering nanostructure, characterized by an exceptionally high number density of co-existing subnanoscale short-range ordering (approximately 2.4 × 1026 m-3) and nanoscale long-range ordering (approximately 4.5 × 1025 m-3) domains, within a metallic solid-solution matrix in a CoNiV-based alloy to improve the synergy of strength and ductility at low temperatures. We observe an ordering-induced increase in dislocation shear stress as well as a more rapid dislocation multiplication owing to the dislocation blocking effect of nanoscale long-range ordering and the associated generation of new dislocations. The latter effect also releases stress concentrations at nanoscale long-range-ordered obstacles that otherwise would promote damage initiation and failure. Consequently, the alloy shows a strength-elongation product of 76 GPa % with a yield strength of approximately 1.2 GPa at 87 K, outperforming materials devoid of such ordering hierarchy, containing only short-range ordered or coherent precipitates of a few tens of nanometres. Our results highlight the impact of dual co-existing chemical ordering on the mechanical properties of complex alloys and offer guidelines to control these ordering states to enhance their mechanical performance for cryogenic applications.
Mechanical engineering, Mechanical properties, Metals and alloys
A compressed hierarchy for visual form processing in the tree shrew
Original Paper | Neural circuits | 2025-08-26 20:00 EDT
Frank F. Lanfranchi, Joseph Wekselblatt, Daniel A. Wagenaar, Doris Y. Tsao
Our knowledge of the brain processes that govern vision is largely derived from studying primates, whose hierarchically organized visual system1 inspired the architecture of deep neural networks2. This raises questions about the universality of such hierarchical structures. Here we examined the large-scale functional organization for vision in one of the closest living relatives to primates, the tree shrew. We performed Neuropixels recordings3,4 across many cortical and thalamic areas spanning the tree shrew ventral visual system while presenting a large battery of visual stimuli in awake tree shrews. We found that receptive field size, response latency and selectivity for naturalistic textures, compared with spectrally matched noise5, all increased moving anteriorly along the tree shrew visual pathway, consistent with a primate-like hierarchical organization6,7. However, tree shrew area V2 already harboured a high-level representation of complex objects. First, V2 encoded a complete representation of a high-level object space8. Second, V2 activity supported the most accurate object decoding and reconstruction among all tree shrew visual areas. In fact, object decoding accuracy from tree shrew V2 was comparable to that in macaque posterior IT and substantially higher than that in macaque V2. Finally, starting in V2, we found strongly face-selective cells resembling those reported in macaque inferotemporal cortex9. Overall, these findings show how core computational principles of visual form processing found in primates are conserved, yet hierarchically compressed, in a small but highly visual mammal.
Neural circuits, Object vision
Cocaine chemogenetics blunts drug-seeking by synthetic physiology
Original Paper | Neural circuits | 2025-08-26 20:00 EDT
Juan L. Gomez, Christopher J. Magnus, Jordi Bonaventura, Oscar Solis, Fallon P. Curry, Marjorie R. Levinstein, Reece C. Budinich, Meghan L. Carlton, Emilya N. Ventriglia, Sherry Lam, Le Wang, Ingrid Schoenborn, William Dunne, Michael Michaelides, Scott M. Sternson
Chemical feedback is ubiquitous in physiology but is challenging to study without perturbing basal functions. One example is addictive drugs, which elicit a positive-feedback cycle of drug-seeking and ingestion by acting on the brain to increase dopamine signalling1,2,3. However, interfering with this process by altering basal dopamine also adversely affects learning, movement, attention and wakefulness4. Here, inspired by physiological control systems, we developed a highly selective synthetic physiology approach to interfere with the positive-feedback cycle of addiction by installing a cocaine-dependent opposing signalling process into this body-brain signalling loop. We used protein engineering to create cocaine-gated ion channels that are selective for cocaine over other drugs and endogenous molecules. Expression of an excitatory cocaine-gated channel in the rat lateral habenula, a brain region that is normally inhibited by cocaine, suppressed cocaine self-administration without affecting food motivation. This artificial cocaine-activated chemogenetic process reduced the cocaine-induced extracellular dopamine rise in the nucleus accumbens. Our results show that cocaine chemogenetics is a selective approach for countering drug reinforcement by clamping dopamine release in the presence of cocaine. In the future, chemogenetic receptors could be developed for additional addictive drugs or hormones and metabolites, which would facilitate efforts to probe their neural circuit mechanisms using a synthetic physiology approach. As these chemogenetic ion channels are specific for cocaine over natural rewards, they may also offer a route towards gene therapies for cocaine addiction.
Neural circuits, Synthetic biology
Optical generative models
Original Paper | Applied optics | 2025-08-26 20:00 EDT
Shiqi Chen, Yuhang Li, Yuntian Wang, Hanlong Chen, Aydogan Ozcan
Generative models cover various application areas, including image and video synthesis, natural language processing and molecular design, among many others1,2,3,4,5,6,7,8,9,10,11. As digital generative models become larger, scalable inference in a fast and energy-efficient manner becomes a challenge12,13,14. Here we present optical generative models inspired by diffusion models4, where a shallow and fast digital encoder first maps random noise into phase patterns that serve as optical generative seeds for a desired data distribution; a jointly trained free-space-based reconfigurable decoder all-optically processes these generative seeds to create images never seen before following the target data distribution. Except for the illumination power and the random seed generation through a shallow encoder, these optical generative models do not consume computing power during the synthesis of the images. We report the optical generation of monochrome and multicolour images of handwritten digits, fashion products, butterflies, human faces and artworks, following the data distributions of MNIST15, Fashion-MNIST16, Butterflies-10017, Celeb-A datasets18, and Van Gogh’s paintings and drawings19, respectively, achieving an overall performance comparable to digital neural-network-based generative models. To experimentally demonstrate optical generative models, we used visible light to generate images of handwritten digits and fashion products. In addition, we generated Van Gogh-style artworks using both monochrome and multiwavelength illumination. These optical generative models might pave the way for energy-efficient and scalable inference tasks, further exploiting the potentials of optics and photonics for artificial-intelligence-generated content.
Applied optics, Engineering, Optical techniques
The evolution of hominin bipedalism in two steps
Original Paper | Biological anthropology | 2025-08-26 20:00 EDT
Gayani Senevirathne, Serena C. Fernandopulle, Daniel Richard, Stephanie L. Baumgart, Anika Liv Christensen, Matteo Fabbri, Jakob Höppner, Harald Jüppner, Peishu Li, Vivien Bothe, Nadia Fröbisch, Ian Simcock, Owen J. Arthurs, Alistair Calder, Naomi Freilich, Niamh C. Nowlan, Ian A. Glass, April Craft, Terence D. Capellini
Bipedalism is a human-defining trait1,2,3. It is made possible by the familiar, bowl-shaped pelvis, whose short, wide iliac blades curve along the sides of the body to stabilize walking and support internal organs and a large-brained, broad-shouldered baby4,5,6. The ilium changes compared with living primates are an evolutionary novelty7. However, how this evolution came about remains unknown. Here, using a multifaceted histological, comparative genomic and functional genomic approach, we identified the developmental bases of the morphogenetic shifts in the human pelvis that made bipedalism possible. First, we observe that the human ilium cartilage growth plate underwent a heterotopic shift, residing perpendicular to the orientation present in other primate (and mouse) ilia. Second, we observe heterochronic and heterotopic shifts in ossification that are unlike those in non-human primate ilia or human long bones. Ossification initiates posteriorly, resides externally with fibroblast (and perichondral) cells contributing to osteoblasts, and is delayed compared with other bones in humans and with primate ilia. Underlying these two shifts are regulatory changes in an integrated chondrocyte-perichondral-osteoblast pathway, involving complex hierarchical interactions between SOX9-ZNF521-PTH1R and RUNX2-FOXP1/2. These innovations facilitated further growth of the human pelvis and the unique formation of the ilium among primates.
Biological anthropology, Bone development, Evolutionary developmental biology, Functional genomics
Extreme armour in the world’s oldest ankylosaur
Original Paper | Palaeontology | 2025-08-26 20:00 EDT
Susannah C. R. Maidment, Driss Ouarhache, Kawtar Ech-charay, Ahmed Oussou, Khadija Boumir, Abdessalam El Khanchoufi, Alison Park, Luke E. Meade, D. Cary Woodruff, Simon Wills, Mike Smith, Paul M. Barrett, Richard J. Butler
The armoured ankylosaurian dinosaurs are best known from Late Cretaceous Northern Hemisphere ecosystems, but their early evolution in the Early-Middle Jurassic is shrouded in mystery due to a poor fossil record1,2. Spicomellus afer was suggested to be the world’s oldest ankylosaur and the first from Africa, but was based on only a single partial rib from the Middle Jurassic of Morocco3. Here we describe a new, much more complete specimen that confirms the ankylosaurian affinities of Spicomellus, and demonstrates that it has uniquely elaborate dermal armour unlike that of any other vertebrate, extant or extinct. The presence of ‘handle’ vertebrae in the tail of Spicomellus indicates that it possessed a tail weapon, overturning current understanding of tail club evolution in ankylosaurs, as these structures were previously thought to have evolved only in the Early Cretaceous4. This ornate armour may have functioned for display as well as defence, and a later reduction to simpler armour with less extravagant osteoderms in Late Cretaceous taxa might indicate a shift towards a primarily defensive function, perhaps in response to increased predation pressures or a switch to combative courtship displays.
Palaeontology, Sexual selection, Taxonomy
Epidemiology models explain rumour spreading during France’s Great Fear of 1789
Original Paper | Complex networks | 2025-08-26 20:00 EDT
Stefano Zapperi, Constant Varlet-Bertrand, Cécile Bastidon, Caterina A. M. La Porta, Antoine Parent
The Great Fear of 1789, a wave of panic and unrest in rural France fuelled by the spreading of rumours, was an important moment at the onset of the French Revolution, marking the collapse of feudalism and the rise of the new regime1. The Great Fear provides a vivid example of the role the spreading of rumours has in driving political changes that might be relevant today2,3. Here, we collect existing historical records related to the Great Fear and use epidemiology tools and models4 to reconstruct the network of its transmission from town to town. In this way, we quantify the spatiotemporal spread of the rumours and compute key epidemiological parameters, such as the basic reproduction number. Exploiting information on the structure of the road network in eighteenth century France5, we estimate the most probable diffusion paths of the Great Fear and quantify the distribution of spreading velocities. By endowing the nodes in our reconstructed network with indicators related to the institutional, demographic and socio-economic conditions of the time6, including literacy, population size, political participation, wheat prices7,8, income and ownership laws9, and the unequal distribution of land ownership, we compute factors associated with spread of the Great Fear. Our analysis sheds light on unresolved historiographic issues on the significance of the Great Fear for the French Revolution, providing a quantitative answer to the unresolved debate between the role of emotions and rationality in explaining its diffusion.
Complex networks, Epidemiology, History
Nature Materials
High-quality narrow black phosphorus nanoribbons with nearly atomically smooth edges and well-defined edge orientation
Original Paper | Electronic devices | 2025-08-26 20:00 EDT
Teng Zhang, Youxin Chen, Zhiyan He, Qinran Liu, Le Chen, Kai Wang, Wenzhe Chen, Kunchan Wang, Xiaowo Ye, Zhuoyang He, Yuyang Zhang, Yanming Zhang, Chenghao Liao, Yuan He, Wenpei Gao, Tianyu Zhang, Bei Hu, Shenghao Jiang, Fangyuan Shi, Shengguang Gao, Xinyue Li, Changxin Chen
Black phosphorus nanoribbons (BPNRs) with a tunable bandgap and intriguing electronic and optical properties hold strong potential for logic applications. However, efficiently producing high-quality BPNRs with precise control over their size and structure remains a great challenge. Here we achieved high-quality, narrow and clean BPNRs with nearly atomically smooth edges and well-defined edge orientation at high yield (up to ~95%) through the sonochemical exfoliation of the synthesized bulk BP crystals with a slightly enlarged lattice parameter along the armchair direction. The resulting BPNRs have widths centred at 32 nm and can be as narrow as 1.5 nm, with edges consistently aligned along the zigzag direction in measured BPNRs with widths ≤340 nm. The formation of one-dimensional BPNRs with zigzag edges is attributed to the introduction of pre-stress along the armchair direction of the grown bulk BP and the application of suitable sonication conditions. The BPNR bandgap increases as the BPNR width decreases from 83 nm to 13 nm, with a large bandgap of 0.64 eV for a 13-nm-wide BPNR. A typical graphene-contacted field-effect transistor fabricated with a 13-nm-wide and 10-nm-thick BPNR can achieve an on/off ratio of 1.7 × 106, mobility of 1,506 cm2 V-1 s-1 and on-state channel conductivity of 1,845 µS. The devices also exhibit excellent photodetection performance. Our method opens up a route to produce BPNRs with high material quality and defined edge chirality for fundamental studies and practical applications in electronic and optoelectronic fields.
Electronic devices, Electronic properties and materials, Nanowires
Nature Physics
Flexoelectricity and surface ferroelectricity of water ice
Original Paper | Phase transitions and critical phenomena | 2025-08-26 20:00 EDT
X. Wen, Q. Ma, A. Mannino, M. Fernandez-Serra, S. Shen, G. Catalan
Frozen water at ambient pressure–common ice, also known as hexagonal Ih ice–is a non-polar material, even though individual water molecules are polar. Consequently, ice is not piezoelectric and cannot generate electricity under pressure. However, it may in principle generate electricity under bending, because the coupling between polarization and strain gradient (flexoelectricity) is always allowed by symmetry. Here we measure the flexoelectricity of ice and find it to be comparable to that of benchmark electroceramics such as TiO2 and SrTiO3. Moreover, the sensitivity of flexoelectric measurements to surface boundary conditions has revealed a ferroelectric phase transition around 160 K confined within the near-surface region of the ice slabs. Beyond potential applications in low-cost transducers made in situ in cold locations, these findings have profound consequences for our understanding of natural phenomena involving ice: our calculations of the flexoelectric charge density generated in ice-graupel collisions inside thunderstorm clouds compare favourably to the experimental charge transferred in such events, suggesting a possible participation of ice flexoelectricity in the generation of lightning.
Phase transitions and critical phenomena, Surfaces, interfaces and thin films
Physical Review Letters
Minimal Example of Quantum Nonclassicality without Freedom of Choice
Research article | Quantum communication | 2025-08-26 06:00 EDT
Pedro Lauand, Davide Poderini, Rafael Rabelo, and Rafael Chaves
Bell’s theorem is often considered the most stringent notion of nonclassicality. The generalization of Bell’s theorem to causal networks offers interesting new perspectives on the phenomenon of quantum nonclassicality and prompts us with a fundamental inquiry: what is the simplest scenario leading to the incompatibility between quantum correlations and the classical theory of causality? Here, we demonstrate that quantum nonclassicality is possible in an entanglement swapping network consisting of only three dichotomic variables, without the need for the locality assumption or external measurement choices. We also show that interventions, a central tool in the field of causal inference, significantly improve the noise robustness of this new kind of nonclassical behavior, making it feasible for experimental tests with current technology.
Phys. Rev. Lett. 135, 090201 (2025)
Quantum communication, Quantum correlations in quantum information, Quantum correlations, foundations & formalism, Quantum foundations
No Practical Quantum Broadcasting: Even Virtually
Research article | Quantum correlations, foundations & formalism | 2025-08-26 06:00 EDT
Yunlong Xiao, Xiangjing Liu, and Zhenhuan Liu
Quantum information cannot be broadcast—an intrinsic limitation imposed by quantum mechanics. However, recent advances in virtual operations offer new insights into the no-broadcasting theorem. Here, we focus on the practical utility and introduce sample efficiency as a fundamental constraint, requiring any practical broadcasting protocol perform no worse than the naive approach of direct preparation and distribution. We prove that no linear process—whether quantum or beyond—can simultaneously uphold sample efficiency, unitary covariance, permutation invariance, and classical consistency. This leads to a no-practical-broadcasting theorem, which places strict limits on the practical distribution of quantum information. By applying Schur-Weyl duality, we establish the uniqueness of the canonical 1-to-$N$ virtual broadcasting map that satisfies the latter three conditions, provide its construction, and determine its sample complexity through semidefinite programming. Finally, we explore the interplay between virtual broadcasting and a quantum spacetime framework, known as the pseudodensity operator, showing that their correspondence holds only in the 1-to-2 case, underscoring the fundamental asymmetry between spatial and temporal statistics in the quantum world.
Phys. Rev. Lett. 135, 090202 (2025)
Quantum correlations, foundations & formalism, Quantum foundations, Quantum information theory
Neutrino Flavor Transformation in Neutron Star Mergers
Research article | Astrophysical studies of gravity | 2025-08-26 06:00 EDT
Yi Qiu, David Radice, Sherwood Richers, and Maitraya Bhattacharyya
A novel numerical-relativity simulation of binary neutron star mergers finds the neutrino flavor transformations could affect the composition and structure of the merger’s remnant.
Phys. Rev. Lett. 135, 091401 (2025)
Astrophysical studies of gravity, Gravitational waves, Nuclear matter in neutron stars, Binary stars, Astrophysical & cosmological simulations, Numerical relativity, Numerical simulations in gravitation & astrophysics
Muon Colliders and the Neutrino Slice
Research article | Lepton colliders | 2025-08-26 06:00 EDT
Luc Bojorquez-Lopez, Matheus Hostert, Carlos A. Argüelles, and Zhen Liu
Muon colliders provide an exciting new direction to expand the energy frontier of particle physics. We point out a new use of these facilities for neutrino and beyond the standard model physics using their main detectors. Muon decays along the accelerator rings create an intense and highly collimated neutrino beam that crosses a thin slice of the kt-scale detector. As a result, it would induce an unprecedented number of neutrino interactions, with $\mathcal{O}({10}^{4})$ events per second for a 10 TeV ${\mu }^{+}{\mu }^{- }$ collider. These interactions are highly energetic and possess a distinct timing signature and a large transverse displacement. We discuss promising applications of these events for instrumentation, electroweak, and beyond-the-standard model physics. For instance, a subpercent measurement of the neutrino-electron scattering rate enables new precision measurements of the Weak angle and a novel detection of the neutrino charge radius.
Phys. Rev. Lett. 135, 091803 (2025)
Lepton colliders, Muon accelerators & neutrino factories, Neutrinos
Axion Dark Matter Search with Sensitivity near the Kim-Shifman-Vainshtein-Zakharov Benchmark Using the ${\mathrm{TM}}_{020}$ Mode
Research article | Dark matter direct detection | 2025-08-26 06:00 EDT
Sungjae Bae, Junu Jeong, Younggeun Kim, SungWoo Youn, Jinsu Kim, Arjan F. van Loo, Yasunobu Nakamura, Seonjeong Oh, Taehyeon Seong, Sergey Uchaikin, Jihn E. Kim, and Yannis K. Semertzidis
Axions, originally proposed to resolve the $CP$ problem in the strong interaction, remain a leading dark matter candidate. While cavity haloscopes offer the most sensitive technique for detecting axions, searches have largely been limited to masses below $10\text{ }\text{ }\mathrm{\mu eV}$. We report a sensitive search for axion dark matter with masses around $21\text{ }\text{ }\mathrm{\mu eV}$, utilizing the ${\mathrm{TM}}_{020}$ mode of a cylindrical cavity equipped with an innovative tuning mechanism. Our search achieved a sensitivity of $1.7\times{}$ the Kim-Shifman-Vainshtein-Zakharov benchmark over a 100-MHz range, representing a significant advance in this mass range. These results demonstrate that higher-order modes provide a viable strategy for extending haloscope searches into previously unexplored higher-mass regions.
Phys. Rev. Lett. 135, 091804 (2025)
Dark matter direct detection, Axions, Cavity resonators
Amplification of Spontaneous Emission from Doubly Excited He Atoms
Research article | Collective effects in atomic physics | 2025-08-26 06:00 EDT
J. Turnšek, Š. Krušič, A. Mihelič, K. Bučar, L. Foglia, R. Mincigrucci, M. Krstulović, M. Coreno, G. Bonano, K. C. Prince, C. Callegari, A. Simoncig, Z. Ebrahimpour, E. Paltanin, A. Benediktovitch, R. Osellame, A. G. Ciriolo, R. Martínez Vázquez, C. Vozzi, E. Principi, and M. Žitnik
We have observed amplification of weak fluorescence from He atoms in the 3a $^{1}{P}^{o}$ autoionizing state, which decay by spontaneous emission of 40.74 eV photons in one out of 1600 cases. On average, a $4.1\pm{}1.6%$ conversion of 63.67 eV photons was detected in the forward direction at $20\text{ }\text{ }\mathrm{\mu }\mathrm{J}$ pump pulse energy and 40 mbar He gas pressure. A comparison with state-of-the-art theoretical simulations shows an unexpected spectral line shift at high gas pressure that is ascribed to transient molecular and electron scattering effects.
Phys. Rev. Lett. 135, 093001 (2025)
Collective effects in atomic physics, Nonlinear optics, Atomic gases, Atomic Properties, Dipole approximation, First-principles calculations, Fluorescence spectroscopy, Nonperturbative methods, Resonance fluorescence, Stochastic differential equations
Cavity-Enabled Real-Time Observation of Individual Atomic Collisions
Research article | Cavity quantum electrodynamics | 2025-08-26 06:00 EDT
Matthew L. Peters, Guoqing Wang (王国庆), David C. Spierings, Niv Drucker, Beili Hu, Meng-Wei Chen, Yu-Ting Chen, and Vladan Vuletić
Using the strong dispersive coupling to a high-cooperativity cavity, we demonstrate fast and nondestructive number-resolved detection of atoms in optical tweezers. We observe individual atom-atom collisions, quantum state jumps, and atom loss events with a time resolution of $100\text{ }\text{ }\mathrm{\mu }\mathrm{s}$ through continuous measurement of cavity transmission. Using adaptive feedback control in combination with the nondestructive measurements, we further prepare a single atom with 92(2)% probability.
Phys. Rev. Lett. 135, 093402 (2025)
Cavity quantum electrodynamics, Cooling & trapping, Interatomic & molecular potentials, Optical pumping, Quantum control, Ultracold collisions
Incoherent Measurement of a Sub-10 kHz Optical Linewidth
Research article | Quantum coherence & coherence measures | 2025-08-26 06:00 EDT
Félix Montjovet-Basset, Jayash Panigrahi, Diana Serrano, Alban Ferrier, Emmanuel Flurin, Patrice Bertet, Alexey Tiranov, and Philippe Goldner
Quantum state lifetimes ${T}{2}$, or equivalently homogeneous linewidths ${\mathrm{\Gamma }}{h}=1/\pi {T}{2}$, are a key parameter for understanding decoherence processes in quantum systems and assessing their potential for applications in quantum technologies. The most common tool for measuring narrow optical homogeneous linewidths, i.e., long ${T}{2}$, is the measurement of coherent photon echo emissions, which however gives very weak signal when the number of emitters is small. This strongly hampers the development of nanomaterials, such as those based on rare earth ions, for quantum communication and processing. In this work, we propose, and demonstrate in an erbium doped crystal, a measurement of photon echoes based on incoherent fluorescence detection and its variance analysis. It gives access to ${T}{2}$ through a much larger signal than direct photon echo detection, and, importantly, with a laser which is incoherent over the measurement timescale, on the order of a few ${T}{2}$. Our results thus open the way to efficiently assess the properties of a broad range of emitters and materials for applications in quantum nanophotonics.
Phys. Rev. Lett. 135, 093601 (2025)
Quantum coherence & coherence measures, Quantum fluids & solids, Rare-earth doped crystals, Coherent control
Self-Injection Locking Dynamics with Raman Actions in Aluminum Nitride Microresonators
Research article | Integrated optics | 2025-08-26 06:00 EDT
Yulei Ding, Yifei Wang, Shunyu Yao, Yanan Guo, Jianchang Yan, Junxi Wang, Changxi Yang, and Chengying Bao
Self-injection locking in an aluminum nitride chip enables stimulated Raman lasers and tunable microcombs via nonlinear Kerr effects and Raman scattering.
Phys. Rev. Lett. 135, 093801 (2025)
Integrated optics, Laser dynamics, Frequency combs & self-phase locking
Analysis of the Blowout Plasma Wakefields Produced by Drive Beams with Elliptical Symmetry
Research article | Plasma-beam interactions | 2025-08-26 06:00 EDT
P. Manwani, Y. Kang, J. Mann, B. Naranjo, G. Andonian, and J. B. Rosenzweig
In the underdense, or blowout regime, of plasma wakefield acceleration, the particle beam is denser than the plasma. In this scenario, the plasma electrons are nearly completely rarefied from the beam channel, leaving only a nominally uniform ion-filled ‘’bubble.’’ Extensive investigations of this interaction assuming axisymmetry have been undertaken. However, the blowout produced by a transversely asymmetric (flat) driver, which would be present in linear collider ‘’afterburner’’ schemes, possesses quite different characteristics. Such beams create an asymmetric plasma bubble which leads to unequal focusing in the two transverse dimensions, accompanied by a nonuniform accelerating gradient. The asymmetric blowout cross section is found through simulation to be elliptical, and treating it as such permits a simple extension of the symmetric theory. In particular, focusing fields linear in both transverse directions inside the bubble are found. The form of the wake potential and the associated beam-matching conditions in this elliptical cavity are discussed. We also examine blowout boundary estimation in the long driver limit and applications of the salient asymmetric features of the wakefield.
Phys. Rev. Lett. 135, 095001 (2025)
Plasma-beam interactions, Advanced accelerator test facilities, Plasma acceleration & new acceleration techniques
Non-Hermitian Origin of Detachable Boundary States in Topological Insulators
Research article | Edge states | 2025-08-26 06:00 EDT
Daichi Nakamura, Ken Shiozaki, Kenji Shimomura, Masatoshi Sato, and Kohei Kawabata
While topology can impose obstructions to exponentially localized Wannier functions, certain topological insulators are exempt from such Wannier obstructions. The absence of the Wannier obstructions can further accompany topological boundary states that are detachable from the bulk bands. Here, we elucidate a close connection between these detachable topological boundary states and non-Hermitian topology. Identifying Hermitian topological boundary states as non-Hermitian topology, we demonstrate that intrinsic non-Hermitian topology leads to the inevitable spectral flow. By contrast, we show that extrinsic non-Hermitian topology underlies the detachment of topological boundary states and clarify anti-Hermitian topology of the detached boundary states. Based on this connection and $K$-theory, we complete the tenfold classification of Wannier localizability and detachable topological boundary states.
Phys. Rev. Lett. 135, 096601 (2025)
Edge states, Surface states, Topological phases of matter, Non-Hermitian systems, Topological materials, Mathematical physics methods, Topology
Structural Contribution to Light-Induced Gap Suppression in ${\mathrm{Ta}}{2}{\mathrm{NiSe}}{5}$
Research article | Exotic phases of matter | 2025-08-26 06:00 EDT
Zijing Chen, Chenhang Xu, Chendi Xie, Weichen Tang, Qiaomei Liu, Dong Wu, Qing Xu, Tao Jiang, Pengfei Zhu, Xiao Zou, Jun Li, Zhiwei Wang, Nanlin Wang, Dong Qian, Alfred Zong, and Dao Xiang
An excitonic insulator is a material that hosts an exotic ground state, where an energy gap opens due to spontaneous condensation of bound electron-hole pairs. ${\mathrm{Ta}}{2}{\mathrm{NiSe}}{5}$ is a promising candidate for this type of material, but the coexistence of a structural phase transition with the gap opening has led to a long-standing debate regarding the origin of the insulating gap. Here we employ MeV ultrafast electron diffraction to obtain quantitative insights into the atomic displacements in ${\mathrm{Ta}}{2}{\mathrm{NiSe}}{5}$ following photoexcitation, which has been overlooked in previous time-resolved spectroscopy studies. In conjunction with first-principles calculations using the measured atomic displacements, we find that the structural change can largely account for the photoinduced reduction in the energy gap without considering excitonic effects. Our Letter illustrates the importance of a quantitative reconstruction of individual atomic pathways during nonequilibrium phase transitions, paving the way for a mechanistic understanding of a diverse array of phase transitions in correlated materials where lattice dynamics can play a pivotal role.
Phys. Rev. Lett. 135, 096901 (2025)
Exotic phases of matter, First-principles calculations, Lattice dynamics, Phase transitions, Ultrafast femtosecond pump probe
Fluctuation-Response Inequalities for Kinetic and Entropic Perturbations
Research article | Fluctuations & noise | 2025-08-26 06:00 EDT
Euijoon Kwon, Hyun-Myung Chun, Hyunggyu Park, and Jae Sung Lee
We derive fluctuation-response inequalities for Markov jump processes that link the fluctuations of general observables to the response to perturbations in the transition rates within a unified framework. These inequalities are derived using the Cram'er-Rao bound, enabling broader applicability compared to existing fluctuation-response relations formulated for static responses of currentlike observables. The fluctuation-response inequalities are valid for a wider class of observables and are applicable to finite observation times through dynamic responses. Furthermore, we extend these inequalities to open quantum systems governed by the Lindblad quantum master equation and find the quantum fluctuation-response inequality, where dynamical activity plays a central role.
Phys. Rev. Lett. 135, 097101 (2025)
Fluctuations & noise, Nonequilibrium statistical mechanics, Quantum thermodynamics, Stochastic thermodynamics, Linear response theory
Three Strongly Coupled Kerr Parametric Oscillators Forming a Boltzmann Machine
Research article | NP-hard problems | 2025-08-26 06:00 EDT
Gabriel Margiani, Orjan Ameye, Oded Zilberberg, and Alexander Eichler
Coupled Kerr parametric oscillators (KPOs) are a promising resource for classical and quantum analog computation, for example to find the ground state of Ising Hamiltonians. Yet, the state space of strongly coupled KPO networks is very involved. As such, their phase diagram sometimes features either too few or too many states, including some that cannot be mapped to Ising spin configurations. This complexity makes it challenging to find and meet the conditions under which an analog optimization algorithm can be successful. Here, we demonstrate how to use three strongly coupled KPOs as a simulator for an Ising Hamiltonian, and estimate its ground state using a Boltzmann sampling measurement. While fully classical, our Letter is directly relevant for quantum systems operating on coherent states.
Phys. Rev. Lett. 135, 097201 (2025)
NP-hard problems, Network optimization, Nonlinear resonance, Parametric resonance, Ising model
Quantifying Disorder in Data
Research article | Chaos | 2025-08-26 06:00 EDT
João Vitor Vieira Flauzino, Thiago Lima Prado, Norbert Marwan, Jürgen Kurths, and Sergio Roberto Lopes
The quantification of disorder in data remains a fundamental challenge in science, as many phenomena yield short length datasets with order-disorder behavior, significant (un)correlated fluctuations, and indistinguishable characteristics even when arising from distinct natures, such as chaotic or stochastic processes. In this Letter, we propose a novel method to directly quantify disorder in data through recurrence microstate analysis, showing that maximizing this measure is essential for its optimal estimation. Our approach reveals that the disorder condition corresponds to the action of the symmetric group on recurrence space, producing classes of equiprobable recurrence microstates. By leveraging information entropy, we define a robust quantifier that reliably differentiates between chaotic, correlated, and uncorrelated stochastic signals even using just small time series. Additionally, it uncovers the characteristics of corrupting noise in dynamical systems. As an application, we show that disorder minima over time often align with well-known stage transitions of the Cenozoic era, indicating periods of dominant drivers in paleoclimatic data.
Phys. Rev. Lett. 135, 097401 (2025)
Chaos, Climate research, Complex systems, Fluctuations & noise, Shannon entropy, Stochastic analysis
Cluster Dynamics in Macroscopic Photoactive Particles
Research article | Clustering | 2025-08-26 06:00 EDT
Sára Lévay, Axel Katona, Hartmut Löwen, Raúl Cruz Hidalgo, and Iker Zuriguel
We present an experimental study on the collective behavior of macroscopic self-propelled particles that are externally excited by light. This property allows for testing the system response to the excitation intensity in a very versatile manner. We discover that, for low excitation intensities, clustering at the boundaries is always present, even when this is prevented by implementing flower-shaped confining walls. For high excitation intensities, however, clusters are dissolved more or less easily depending on their size. Then, a thorough analysis of the cluster dynamics allows us to depict a phase diagram depending on the number of agents in the arena and the excitation intensity. To explain this, we introduce a simple kinetic model where cluster evolution is governed by a balance between adsorption and desorption processes. Interestingly, this simple model is able to reproduce the phase space observed experimentally.
Phys. Rev. Lett. 135, 098301 (2025)
Clustering, Emergence of patterns, Granular materials, Dry active matter, Living matter & active matter, Self-propelled particles
Physical Review X
Experimentally Probing Entropy Reduction via Iterative Quantum Information Transfer
Research article | Fluctuation theorems | 2025-08-26 06:00 EDT
Toshihiro Yada, Pieter-Jan Stas, Aziza Suleymanzade, Erik N. Knall, Nobuyuki Yoshioka, Takahiro Sagawa, and Mikhail D. Lukin
Tracking real-time feedback on a spin qubit reveals how quantum information flow sets thermodynamic limits and shows that feedback with memory enables enhanced control performance compared to memoryless methods.
Phys. Rev. X 15, 031054 (2025)
Fluctuation theorems, Information thermodynamics, Quantum feedback, Quantum information with solid state qubits, Quantum thermodynamics
High-Power Clock Laser Spectrally Tailored for High-Fidelity Quantum State Engineering
Research article | Atomic, optical & lattice clocks | 2025-08-26 06:00 EDT
Lingfeng Yan, Stefan Lannig, William R. Milner, Max N. Frankel, Ben Lewis, Dahyeon Lee, Kyungtae Kim, and Jun Ye
A custom-designed optical clock laser achieves notably high, single-qubit optical-gate fidelity across 3000 atoms, advancing scalable, high-precision control for quantum computing, sensing, and next-generation atomic clocks.
Phys. Rev. X 15, 031055 (2025)
Atomic, optical & lattice clocks, Coherent control, Lasers, Light-matter interaction, Quantum control, Quantum sensing, Atomic gases, Laser systems, Ultracold gases, Optical lattices & traps
arXiv
Computational study of alpha-ray induced electron excitation in diamonds for radiation detection
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Atsuhiro Umemoto, Yoshiyuki Miyamoto
To investigate the mechanism of radiation detection in diamonds, we developed a real time time dependent density functional theory based calculation scheme to evaluate changes in the density of states induced by alpha ray irradiation. A bulk diamond structural model was constructed, with impurities optionally introduced to assess their effect on electronic excitation. Simulations revealed that the passage of high speed helium ions, representing alpha particles, produced significant electronic excitation in the diamond model. Subsequent calculations of the excited state dynamics after ion removal indicated that excitation can persist for several hundred femtoseconds without triggering nonradiative relaxation. These findings demonstrate that the proposed approach offers a robust theoretical framework for evaluating the performance of diamond-based radiation detectors.
Materials Science (cond-mat.mtrl-sci)
13 pages, 8 figures
Odd relaxation in three-dimensional Fermi liquids
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Seth Musser, Sankar Das Sarma, Johannes Hofmann
Recent theoretical works predict a hierarchy of long-lived, non-hydrodynamic modes in two-dimensional Fermi liquids arising from the feature – supposedly unique to two dimensions – that relaxation by head-on scattering is not efficient in the presence of Pauli blocking. This leads to a parity-based separation of scattering rates, with odd-parity modes relaxing much more slowly than even-parity ones. In this work, we establish that a similar effect exists in isotropic three-dimensional Fermi liquids, even though relaxation does not proceed solely by head-on scattering. We show that while the relaxation rates of even and odd modes in 3D share the same leading-order $ \sim T^2$ low-temperature scaling typical of Fermi liquids, their magnitudes differ, with odd-parity modes relaxing more slowly than even ones for a broad class of interactions. We find a relative difference between odd-and even-parity relaxation rates as large as $ 40%$ just by Pauli blocking alone, with a strong additional dependence on the scattering potential, such that the odd-even staggering is further enhanced by interactions that favor large-angle scattering. We identify signatures of these odd-parity relaxation rates in the static transverse conductivity as well as the transverse collective mode structure. Our results establish the unexpected existence of a tomographic-like regime in higher-dimensional Fermi liquids and suggest experimental probes via transport measurements.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el)
18 pages, 6 figures
Light-induced odd-parity altermagnets on dimerized lattices
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Dongling Liu, Zheng-Yang Zhuang, Di Zhu, Zhigang Wu, Zhongbo Yan
Altermagnets are an emerging class of collinear magnets with momentum-dependent spin splitting and zero net magnetization. These materials can be broadly classified into two categories based on the behavior of spin splitting at time-reversal-related momenta: even-parity and odd-parity altermagnets. While even-parity altermagnets have been thoroughly investigated both theoretically and experimentally, the systems capable of hosting odd-parity altermagnetism remain largely unexplored. In this work, we demonstrate that circularly polarized light dynamically converts collinear PT-symmetric antiferromagnets on dimerized lattices into odd parity p-wave altermagnets. Because of the underlying Dirac band structure of the dimerized lattice, we find that the resulting p-wave altermagnets can realize Chern insulators (2D) and Weyl semimetals (3D) under appropriate drive conditions. Our findings demonstrate that collinear antiferromagnets on dimerized lattices provide ideal platforms to investigate the dynamical generation of odd-parity altermagnetism.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 4 figures
Odd-Parity Altermagnetism Originated from Orbital Orders
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Zheng-Yang Zhuang, Di Zhu, Dongling Liu, Zhigang Wu, Zhongbo Yan
Odd-parity spin-splitting plays a central role in spintronics and unconventional superconductivity, yet its microscopic realization in collinear magnetic systems remains elusive. We propose a general symmetry-based strategy for realizing odd-parity altermagnetism by stacking two noncentrosymmetric monolayers in an interlayer antiferromagnetic configuration and applying an in-plane layer-flip operation. In this setting, odd-parity spin-splitting originates from nonrelativistic orbital orders rather than spin-orbit coupling, and is protected by an effective time-reversal symmetry despite the explicit time-reversal symmetry being broken. By exploiting lattice symmetries, our framework enables the realization of both $ p$ - and $ f$ -wave altermagnets. The resulting models generically host quantum spin Hall insulator phases, featuring topologically protected helical edge states and quantized spin Hall conductance. Our work expands the landscape of altermagnetic phases and opens a pathway toward spintronics and unconventional superconductivity in altermagnetic systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
5 pages, 4 figures. Comments are welcome
3D microwave imaging of a van der Waals heterostructure
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Leonard W. Cao, Chen Wu, Lingyuan Lyu, Liam Cohen, Noah Samuelson, Ziying Yan, Sneh Pancholi, Kenji Watanabe, Takashi Taniguchi, Daniel E. Parker, Andrea F. Young, Monica T. Allen
Van der Waals (vdW) heterostructures offer a tunable platform for the realization of emergent phenomena in layered electron systems. While scanning probe microscopy techniques have proven useful for the characterization of surface states and 2D crystals, the subsurface imaging of quantum phenomena in multi-layer systems presents a significant challenge. In 3D heterostructures, states that occupy different planes can simultaneously contribute to the signal detected by the microscope probe, which complicates image analysis and interpretation. Here we present a quantum imaging technique that offers a glimpse into the third dimension by resolving states out of plane: it extracts the charge density landscape of individual atomic planes inside a vdW heterostructure, layer by layer. As a proof-of-concept, we perform layer-resolved imaging of quantum Hall states and charge disorder in double-layer graphene using milliKelvin microwave impedance microscopy. Here the discrete energy spectrum of the top layer enables transmission of microwaves through gapped states, thus opening direct access to quantum phases in the subsurface layer. Resolving how charge is distributed out-of-plane offers a direct probe of interlayer screening, revealing signatures of negative quantum capacitance driven by many-body correlations. At the same time, we extract key features of the band structure and thermodynamics, including gap sizes. Notably, by imaging the charge distribution on different atomic planes beneath the surface, we shed light on the roles of surface impurities and screening on the stability of fractional quantum Hall states. We also show that the uppermost graphene layer can serve as a top gate: This unlocks access to a wide range of phenomena that require displacement field control, from fractional Chern insulators in Moiré superlattices to correlated states in multilayer graphene.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Destructive Interference induced constraints in Floquet systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-27 20:00 EDT
Somsubhra Ghosh, Indranil Paul, K. Sengupta, Lev Vidmar
We introduce the paradigm of destructive many-body interference between quantum trajectories as a means to systematically generate prethermal kinetically constrained dynamics in Floquet systems driven at special frequencies. Depending on the processes that are suppressed by interference, the constraint may or may not be associated with an emergent global conservation; the latter kind having no mechanism of generation in time-independent settings. As an example, we construct an one-dimensional interacting spin model exhibiting strong Hilbert space fragmentation with and without dipole moment conservation, depending on the drive frequency. By probing the spatiotemporal profile of the out-of-time-ordered correlator, we show that this model, in particular, has initial states in which quantum information can be spatially localized - a useful feature in the field of quantum technologies. Our paradigm unifies various types of Hilbert space fragmentation that can be realized in driven systems.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
4.5 + 12 pages, 3 + 5 figures
High-throughput superconducting $T_{\mathrm{c}}$ predictions through density of states rescaling
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-27 20:00 EDT
Kieran Bozier, Kang Wang, Bartomeu Monserrat, Chris J. Pickard
First principles computational methods can predict the superconducting critical temperature $ T_{\mathrm{c}}$ of conventional superconductors through the electron-phonon spectral function. Full convergence of this quantity requires Brillouin zone integration on very dense grids, presenting a bottleneck to high-throughput screening for high $ T_{\mathrm{c}}$ systems. In this work, we show that an electron-phonon spectral function calculated at low cost on a coarse grid yields accurate $ T_{\mathrm{c}}$ predictions, provided the function is rescaled to correct for the inaccurate value of the density of states at the Fermi energy on coarser grids. Compared to standard approaches, the method converges rapidly and improves the accuracy of predictions for systems with sharp features in the density of states. This approach can be directly integrated into existing materials screening workflows, enabling the rapid identification of promising candidates that might otherwise be overlooked.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
11 pages, 6 figures
Multiple Dirac Spin-Orbital Liquids in SU(4) Heisenberg Antiferromagnets on the Honeycomb Lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-27 20:00 EDT
Manoj Gupta, Arijit Haldar, Subhro Bhattacharjee, Tanusri Saha-Dasgupta
We study the strong coupling model of $ d^1$ transition metal tri-halides in the large spin-orbit coupled limit. By considering ab-initio-calculation-inspired hierarchy of hopping pathways of these compounds, SU(4) symmetry is found to emerge at multiple points in the parameter space of the hopping parameters. The resultant Dirac spin-orbital liquids, within the parton mean field description, are distinct. The calculated dynamical structure factor fingerprints this distinctive nature, giving rise to observable effects. This opens up a playground for SU(4) Dirac Spin-Orbital liquid in $ d^1$ Honeycomb lattice systems.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
6 pages, 5 figures; supplementary material included with additional details
Higher-Dimensional Chirally Stabilized Fixed Points and Their Deformations
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-27 20:00 EDT
Aleksandar Ljepoja, L. C. R. Wijewardhana, Yashar Komijani
Non-Fermi liquids in $ d>2$ remain poorly understood, particularly when relevant perturbations destabilize them. In one spatial dimension, chirally stabilized fixed points provide a rare class of analytically tractable non-Fermi-liquid critical points, but their higher-dimensional analogues have been elusive. Here, we develop a Wilsonian operator-product-expansion renormalization group scheme that captures power-divergent terms and use it to construct finite-$ N$ higher-dimensional analogues of chirally stabilized fixed points in arbitrary dimension $ d\le4$ . This exposes a conformal window at finite $ N$ . We further show that symmetry-breaking masses, far from being trivial, can collapse this window and drive the system to strong coupling, triggering dynamical mass generation.
Strongly Correlated Electrons (cond-mat.str-el)
Interplay of Intersite Charge Transfer, Antiferromagnetism, and Strain in Barocaloric ACu$_3$Fe$4$O${12}$ Quadruple Perovskites
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-27 20:00 EDT
J. Delgado-Quesada, G. G. Guzmán-Verri
We develop a minimal Landau theory for the concomitant intersite charge-transfer, antiferromagnetic, and isostructural phase transitions in ACu$ _3$ Fe$ _4$ O$ _{12}$ perovskites (A = La, Pr, Nd, Sm, Eu, Gd, Tb). The model incorporates the difference in average ligand-hole occupancy between Cu and Fe, the staggered magnetization of the Fe sublattice, volume strain, and intrinsic thermal expansion, together with their couplings. It qualitatively reproduces key thermodynamic properties of the ACu$ _3$ Fe$ _4$ O$ _{12}$ family, including the staggered magnetization, lattice volume, magnetic susceptibility, and the nearly linear temperature-pressure phase boundary. The framework predicts a pronounced elastic softening near the phase boundary, consistent with experiments where the bulk modulus of the low-pressure, charge-transferred antiferromagnetic phase exceeds that of the high-pressure, non-transferred paramagnetic phase. It also yields pressure-driven isothermal entropy changes, revealing that the intrinsic thermal expansion of the high- and low-temperature phases significantly shapes the overall barocaloric response. These results contrast with previous analyses of NdCu$ _3$ Fe$ _4$ O$ _{12}$ , where thermal expansion was neglected in the entropy construction, and call for a reevaluation of barocaloric effects in quadruple perovskites.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
19 pages, 4 figures
Parity Breaking at Faceted Crystal Growth Fronts during Ice Templating
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Directional solidification of water-based solutions has emerged as a versatile technique to template hierarchical porous materials, but this nonequilibrium process remains incompletely understood. Here we use phase-field simulations to shed light on the mechanism that selects the growth direction of the lamellar ice structure that templates those materials. Our results show that this selection can be understood within the general framework of spontaneous parity breaking, yielding quantitative predictions for the tilt angle of lamellae with respect to the thermal axis. The results provide a theoretical basis to interpret a wide range of experimental observations.
Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft)
Phase-Field Model of Freeze Casting
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Directional solidification of water-based solutions has emerged as a versatile technique for templating hierarchical porous materials. However, the underlying mechanisms of pattern formation remain incompletely understood. In this work, we present a detailed derivation and analysis of a quantitative phase-field model for simulating this nonequilibrium process. The phase-field model extends the thin-interface formulation of dilute binary alloy solidification with anti-trapping to incorporate the highly anisotropic energetic and kinetic properties of the partially faceted ice-water interface. This interface is faceted in the basal plane normal to the <0001> directions and atomically rough in other directions within the basal plane. On the basal plane, the model reproduces a linear or nonlinear kinetic relationship that can be linked to experimental measurements. In both cases, spontaneous parity breaking of the solidification front is observed, leading to the formation of partially faceted ice lamellae that drift laterally in one of the <0001> directions. We demonstrate that the drifting velocity is controlled by the kinetics on the basal plane and converges as the thickness of the diffuse solid-liquid interface decreases. Furthermore, we examine the effect of the form of the kinetic anisotropy, which is chosen here such that the inverse of the kinetic coefficient varies linearly from a finite value in the <0001> directions to zero in all other directions within the basal plane. Our results indicate that the drifting velocity of ice lamellae is not affected by the slope of this linear relation, and the radius and undercooling at the tip of an ice lamella converge at relatively small slope values. Consequently, the phase-field simulations remain quantitative with computationally tractable choices of both the interface thickness and the slope assumed in the form of the kinetic anisotropy.
Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft)
Why Compressed Metal Hydrides are Near-room-temperature Superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-27 20:00 EDT
This contribution provides a partial response to the titular statement since, it will be claimed,the why'' is not yet understood, but there is a pathway for achieving a more complete understanding. The sense of the community has been that, given a prospective metal hydride and pressure, the energy landscape can be surveyed computationally for thermodynamic and dynamic stability, the Eliashberg spectral function with its required input (energy bands, phonon modes, coupling matrix elements) can be calculated, and the critical temperature T$ _c$ obtained. Satisfyingly large values of the electron-phonon coupling strength $ \lambda$ =2-3 at high mean frequency are obtained, giving very reasonable agreement with existing high T$ _c$ hydrides. Typically 80-85\% of $ \lambda$ is attributable to high frequency H vibrations. This much was envisioned by Ashcroft two decades ago, so why should there be any angst? This paper addresses more specifically the question {\it why hydrogen?} Light mass is indeed a factor, but with possibilities not yet explored. This paper provides a concise overview of related formal developments occurring sporadically over several decades that, when implemented, could resolve the question of {\it why hydrogen, why so high T$ _c$ .} The dearth of success of numerous high throughput searches proposing higher T$ _c$ materials, especially hydrides, is touched on briefly. Based on as yet unapplied developments in simplifying effects of atomic displacement, it is proposed that there is a straightforward path toward a deeper understanding of metallic hydrogen superconductivity” in conjunction with added computational efficiency, and that some human-learning should assist in focusing the search for higher T$ _c$ superconductors.
Superconductivity (cond-mat.supr-con)
14 pages, 6 figures
Rigidity and mechanical response in biological structures
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-27 20:00 EDT
Kelly Aspinwall, Tyler Hain, M. Lisa Manning
Rigidity is an emergent property of materials - it is not a feature of individual components that comprise the structure, but instead arises from interactions between many constituent parts. Recently, it has been recognized that floppy-rigid or fluid-solid transitions are harnessed by biological systems at all scales to drive form and function. This review focuses on the different mechanisms that can drive emergent rigidity transitions in biomechanical networks, and describes how they arise in mathematical formalisms and how they are observed in practice in experiments. The goal is to aid researchers in identifying mechanisms governing rigidity in their biological systems of interest, highlight mechanical features that are universal across different systems, and help drive new scientific hypotheses for observed mechanical phenomena in biology. Looking forward, we also discuss how biological systems might tune themselves towards or away from such transitions over developmental or evolutionary timescales.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Exploration of Hexagonal, Layered Carbides and Nitrides as Ultra-High Temperature Ceramics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Kat Nykiel, Brian Wyatt, Babak Anasori, Alejandro Strachan
Layered, hexagonal crystal structures, like zeta and eta phases, play an important role in ultra-high temperature ceramics, often significantly increasing toughness of carbide composites. Despite their importance open questions remain about their structure, stability, and compositional pervasiveness. We use high-throughput density functional theory to characterize the thermodynamic stability and elastic constants of layered carbides and nitrides M$ _{n+1}$ X$ _{n}$ with $ n$ = 1, 2, and 3, $ M$ = Ta, Ti, Hf, Zr, Nb, Mo, V, W, Sc, Cr, Mn and $ X$ = C, N. The stacking sequences explored are inspired by the possible use of MXenes as precursors to enable relatively low temperature processing of high-temperature ceramics. We identified 67 new hexagonal, layered materials with thermal stability comparable or better than previously observed zeta phases. To assess their potential for high temperature applications, we used machine learning and physics-based models with DFT inputs to predict their melting temperatures and discovered several candidates on par with the current state of the art zeta-like phases and five with predicted melting temperatures above 2500 K. The findings expand the range of chemistries and structures for high-temperature applications.
Materials Science (cond-mat.mtrl-sci)
Scalable Effective Models for Superconducting Nanostructures: Applications to Double, Triple, and Quadruple Quantum Dots
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Daniel Bobok, Lukáš Frk, Vladislav Pokorný, Martin Žonda
We introduce a versatile and scalable framework for constructing effective models of superconducting (SC) nanostructures described by the generalized SC Anderson impurity model with multiple quantum dots and leads. Our Chain Expansion (ChE) method maps each SC lead onto a finite tight-binding chain with parameters obtained from Padé approximants of the tunneling self-energy. We provide an explicit algorithm for the general case as well as simple analytical expressions for the chain parameters in the wide-band and infinite-chain limits. This mapping preserves low-energy physics while enabling efficient simulations: short chains are tractable with exact diagonalization, and longer ones with density matrix renormalization group methods. The approach remains reliable and computationally efficient across diverse geometries, both in and out of equilibrium. We use ChE to map the ground-state phase diagrams of double, triple, and quadruple quantum dots coupled to a single SC lead. While half-filled symmetric systems show similar overall diagrams, the particular phases differ substantially with dot number. Here, large parameter regions are entirely missed by the widely used zero-bandwidth approximation but are captured by ChE. Away from half-filling, additional dots markedly increase diagram complexity, producing a rich variety of stable phases. These results demonstrate ChE as a fast, accurate, and systematically improvable tool for exploring complex SC nanostructures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
26 pages, 30 figures
Parameter degeneracy in the vertex model for tissues
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-27 20:00 EDT
Paulo C. Godolphim, Leonardo G. Brunnet, Rodrigo Soto
The vertex model with homogeneous cell properties is known to exhibit a parameter degeneracy in which the system’s dynamics is independent of the target area. Here, we show, for the heterogeneous vertex model where cells differ in size and stiffness, that degeneracy is also present with the average product of target areas and stiffness becoming dynamically irrelevant. Fixing this quantity is equivalent to fixing the global internal tissue pressure. Unless properly treated, this degeneracy undermines the physical relevance of key observables’ numerical values, such as the shape index, cell pressure, and cell stress tensor. We present methods to resolve the degeneracy and to correctly set the gauge pressure via symmetry transformations applied to the cells’ target areas. We further demonstrate that the degeneracy is removed under certain boundary conditions and partially lifted when spherical tissues are modeled using a locally planar approximation, leading to numerical consequences when fitting model parameters to experimental data. The approach extends beyond vertex models and provides a framework for testing whether the parameter spaces of other physical models are free from degeneracy.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Electron-Phonon interaction and lattice thermal conductivity from metals to 2D Dirac crystals: a review
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Sina Kazemian, Giovanni Fanchini
Electron–phonon (e–ph) coupling governs electrical resistivity, hot-carrier cooling, and critically, thermal transport in solids. Recent first-principles advances now predict e–ph limited thermal conductivity from d-band metals and wide-band-gap semiconductors to 2D Dirac crystals without empirical parameters. In bulk metals, ab-initio lifetimes show that phonons, though secondary, still carry up to 40% of the heat once e–ph scattering is included. We next survey coupled Boltzmann frameworks, exemplified by \textsc{elphbolt}, that capture mutual drag and ultrafast non-equilibrium in semiconductors. For 2D Dirac crystals, mirror symmetry, carrier density, strain, and finite size rearrange the scattering hierarchy: ZA modes dominate pristine graphene yet become the main resistive branch in nanoribbons once symmetry is broken. At low Fermi energies and high temperatures, the standard 3-particle decay is partially cancelled, elevating 4-particle processes and necessitating dynamically screened, higher-order theory. Throughout, we identify the microscopic levers such as the electronic density of states, phonon frequency, deformation potential, and show how doping, strain, or dielectric environment can tune e–ph damping. We conclude by outlining open challenges such as: developing coupled e–ph solvers, solving the full mode-to-mode Peierls–Boltzmann equation with 4-particle terms, embedding correlated electron methods in e–ph workflows, and leveraging higher-order e–ph coupling and symmetry breaking to realise phononic thermal diodes and rectifiers. Solving these challenges will elevate e–ph theory from a diagnostic tool to a predictive, parameter-free platform that links symmetry, screening, and many-body effects to heat and charge transport in next-generation electronic, photonic, and thermoelectric devices.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Twisted light drives chiral excitations of interacting electrons in nanostructures with magnetic field
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
F.J. Rodríguez, L. Quiroga, N.F.Johnson
Twisted light (TL), a special kind of light carrying orbital angular momentum, provides a powerful tool for driving symmetry resolved transitions in quantum confined nanostructures. We study a realistic model where a TL pulse excites two interacting electrons in a nanostructure under a perpendicular magnetic field. To include image charge effects in layered systems, we use an effective electron electron potential of the form 1/r^n. For n = 2, the system exhibits an underlying su(1,1) dynamical symmetry, enabling analytical solutions and a clear interpretation of selection rules, parity changes, and angular momentum resolved absorption. We show that the bare Coulomb 1/r interaction produces similar spectra, indicating that twisted light driven excitations are robust against the precise interaction form. The excitation spectrum reveals strong chiral properties: TL pulses, unlike conventional dipolar fields, directly access interaction-driven transitions otherwise symmetry-forbidden. In particular, TL breaks the generalized Kohn theorem, exposing internal excitations through multi quanta orbital processes. More broadly, our results establish TL as a sensitive probe of correlations, symmetry, and magneto-optical dynamics in strongly interacting quantum systems, uncovering features that remain invisible to standard infrared absorption.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
8 figures. Accepted for publication in PRB
Long lifetimes of nanoscale skyrmions in lithium-decorated van der Waals ferromagnet Fe$_3$GeTe$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Soumyajyoti Haldar, Moritz A. Goerzen, Stefan Heinze, Dongzhe Li
The Dzyaloshinskii-Moriya interaction (DMI), which originates from spin-orbit coupling and relies on broken inversion symmetry, is recognized as a key ingredient in forming magnetic skyrmions. However, most 2D magnets exhibit inversion symmetry; therefore, the DMI is suppressed. Here, we propose a strategy to induce large DMI via lithium absorption on the surface of 2D magnets – an experimentally feasible approach. Using first-principles and atomistic spin simulations, we predict the formation of nanoscale skyrmions in lithium-decorated monolayer Fe$ _3$ GeTe$ _2$ by imposing small out-of-plane magnetic fields ($ B_z$ ). Notably, we find very large skyrmion energy barriers of more than 300 meV at $ B_z = 0.4$ T, comparable to those observed in ferromagnet/heavy-metal interfaces. The origin of these unique skyrmions is attributed to the competition between strong DMI, exchange frustration, and small magnetocrystalline anisotropy energy. We further show that the lifetimes of metastable skyrmions exceed one hour for temperatures up to 75 K.
Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
Diverse, Distinct, and Densely Packed DNA Droplets
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-27 20:00 EDT
Aria S. Chaderjian, Sam Wilken, Omar A. Saleh
The liquid-liquid phase separation of biomolecules is an important process for intracellular organization. Biomolecular sequence combinatorics leads to a large variety of proteins and nucleic acids which can interact to form a diversity of dense liquid (`condensate’) phases. The relationship between sequence design and the diversity of the resultant phases is therefore of interest. Here, we explore this question using the DNA nanostar system which permits the creation of multi-phase condensate droplets through sequence engineering of the sticky end bonds that drive particle-particle attraction. We explore the theoretical limits of nanostar phase diversity, then experimentally demonstrate the ability to create 9 distinct, non-adhering nanostar phases that do not share components. We further study how thermal processing affects the morphology and dynamics of such a highly diverse condensate system. We particularly show that a rapid temperature quench leads to the formation of a densely packed 2-D layer of droplets that is transiently stabilized by caging effects enabled by the phase diversity, leading to glassy dynamics, such as slow coarsening and dynamic heterogeneity. Generally, our work provides experimental insight into the thermodynamics of phase separation of complex mixtures and demonstrates the rational engineering of complex, long-range, multi-phase droplet structures.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
A supplemental PDF and 3 supplemental videos are included
Ice-assisted soft-landing deposition for van der Waals integration
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Xinyu Sun, Xiang Xu, BinBin Jin, Yihan Lu, Jichuang Shen, Wei Kong, Ding Zhao, Min Qiu
Van der Waals integration enables the creation of electronic and optoelectronic devices with unprecedented performance and novel functionalities beyond the existing material limitations. However, it is typically realized using a physical pick-up-and-place process to minimize interfacial damages and is hardly integrated into conventional lithography and metallization procedures. Here we demonstrate a simple in situ transfer strategy for van der Waals integration, in which a thin film of amorphous water ice acts as a buffer layer to shield against the bombardment of energetic clusters during metallization. After ice sublimation, the deposited metal film can be gently and in situ placed onto underlying substrates, to form an atomically clean and damage-free metal-semiconductor interface. This strategy allows ultra-clean and non-destructive fabrication of high-quality contacts on monolayer MoS2, which is extremely beneficial to produce a high-performance 2D field-effect transistor with an ultra-high on/off ratio of 1010, mobility of 80 (cm2 V-1s-1), and also with reduced Fermi level pinning effect. We also demonstrate the batch production of CVD-grown MoS2 transistor arrays with uniform electrical characteristics. Such a gentle and ultra-clean fabrication approach has been further extended to materials with high reactivity, such as halide perovskites. Our method can be easily integrated with mature semiconductor manufacturing technology and may become a generic strategy for fabricating van der Waals contacted devices.
Materials Science (cond-mat.mtrl-sci), Instrumentation and Detectors (physics.ins-det)
Light-programmable reorientation of the crystallographic c-axis of Tellurium thin films
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Yuta Kobayashi, Arata Mitsuzuka, Haruo Kondo, Makoto Shoshin, Jun Uzuhashi, Tadakatsu Ohkubo, Masamitsu Hayashi, Masashi Kawaguchi
Tellurium (Te), a two-dimensional material with pronounced structural anisotropy, exhibits exceptional electrical and optical properties that are highly sensitive to its crystallographic orientation. However, conventional synthesis techniques offer limited control over the in-plane alignment of Te’s crystallographic c-axis, hindering large-scale integration. Here, we report a novel, non-contact method to dynamically manipulate the c-axis orientation of Te thin films using linearly polarized picosecond laser pulses. We show that the c-axis can be omnidirectionally reoriented perpendicular to the laser polarization, even in initially polycrystalline films. This reorientation is fully reversible, allowing for rewritable and spatially selective control of the c-axis orientation post-deposition. Our light-driven approach enables programmable anisotropy in Te, opening new avenues for reconfigurable optoelectronic and photonic devices, such as active metasurfaces and CMOS-compatible architectures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Spin-Orbit Coupling-Driven Chirality Switching of Spin Waves in Altermagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Wen-Tong Li, Yu-Biao Wu, Lin Zhuang, Jian-Tao Wang, Wu-Ming Liu
Chirality of spin waves offers an advantageous binary carrier for data transmission and processing with ultrafast dynamics and low power consumption. Altermagnets possess intrinsic chirality-splitting spin waves and vanishing net magnetization, thus emerging as ideal platforms to host chirality bits. However, active control of the chiral states remains a key challenge for realizing logic operations in chirality-based circuits. Here, we propose a novel scheme for reversibly switching spin-wave chirality in altermagnets between right- and left-handedness by tuning spin-orbit coupling (SOC) strength. Specifically, for in-plane spin polarization, SOC hybridizes with the altermagnetism, which induces a momentum-dependent competition. The chirality-splitting structure of spin waves is dominated by either SOC or altermagnetism in different Brillouin zone regions, allowing chirality switching by altering their relative strength. An experimental design utilizing an antiferromagnetic substrate to induce SOC and a heavy-metal stripe for chirality detection is proposed. Our work establishes a novel pathway for controlling spin-wave chirality in altermagnets via SOC, laying the groundwork for developing spintronic devices utilizing switchable chiral spin waves as dynamic information carriers.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Rigidity of generic random tensegrity structures
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-27 20:00 EDT
Vishal Sudhakar, William Stephenson, James P. McInerney, D. Zeb Rocklin
Many mechanical structures, both engineered and biological, combine heavy rigid elements such as bones and beams with lightweight flexible ones such as cables and membranes. These are referred to as tensegrities, reflecting that cables can only support extensile tension. We model such systems via simulations of depleted triangular lattices in which we minimize the energies of tensegrities subject to strained boundary conditions. When there are equal numbers of cables and struts (which support only compressive tension), a cable and a strut together each contribute as much toward rigidity as a rod, with the two contributions being equal in the case of shear strain. Due to the highly nonaffine deformations at the rigidity transitions, the contribution of a cable (strut) can be significant even under global compression (dilation) despite a cable’s inability to resist local compression. Further, we find that when neighboring elements tend to point away from one another, as is common in real systems, cables interact significantly more strongly with other cables than do cables with struts in supporting stress. These phenomena shed new light on a variety of realistic, disordered systems at the threshold of mechanical stability.
Soft Condensed Matter (cond-mat.soft)
7 pages, 4 figures
Full counting statistics and first-passage times in quantum Markovian processes: Ensemble relations, metastability, and fluctuation theorems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-27 20:00 EDT
Paul Menczel, Christian Flindt, Fredrik Brange, Franco Nori, Clemens Gneiting
We develop a comprehensive framework for characterizing fluctuations in quantum transport and nonequilibrium thermodynamics using two complementary approaches: full counting statistics and first-passage times. Focusing on open quantum systems governed by Markovian Lindblad dynamics, we derive general ensemble relations that connect the two approaches at all times, and we clarify how the steady states reached at long times relate to those reached at large jump counts. In regimes of metastability, long-lived intermediate states cause violations of experimentally testable cumulant relations, as we discuss. We also formulate a fluctuation theorem governing the probability of rare fluctuations in the first-passage time distributions based on results from full counting statistics. Our results apply to general integer-valued trajectory observables that do not necessarily increase monotonically in time. Three illustrative applications, a two-state emitter, a driven qubit, and a variant of the Su-Schrieffer-Heeger model, highlight the physical implications of our results and provide guidelines for practical calculations. Our framework provides a complete picture of first-passage time statistics in Markovian quantum systems, encompassing multiple earlier results, and it has direct implications for current experiments in quantum optics, superconducting circuits, and nanoscale heat engines.
Statistical Mechanics (cond-mat.stat-mech), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
27 pages, 8 figures
Optical Control of Integer and Fractional Chern Insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
William Holtzmann, Weijie Li, Eric Anderson, Jiaqi Cai, Heonjoon Park, Chaowei Hu, Takashi Taniguchi, Kenji Watanabe, Jiun-Haw Chu, Di Xiao, Ting Cao, Xiaodong Xu
Optical control of topology, particularly in the presence of electron correlations, is a fascinating topic with broad scientific and technological impact. Twisted MoTe$ _2$ bilayer (tMoTe$ _2$ ) is a newly discovered zero-field fractional Chern insulator (FCI), exhibiting the fractionally quantized anomalous Hall (FQAH) effect. Since the chirality of the edge states and sign of the Chern number are determined by the underlying ferromagnetic polarization, manipulation of ferromagnetism would realize control of the CI/FCI states. Here, we demonstrate control and switching of ferromagnetic polarization, and thus the CI and FCI states by circularly polarized optical pumping in tMoTe$ _2$ . At low optical excitation power, we achieve on-demand preparation of ferromagnetic polarization by optical training, i.e., electrically tuning the system from non-ferromagnetic to desirable ferromagnetic states accompanied with helicity-selective optical pumping. With increased excitation power, we further realize direct optical switching of ferromagnetic polarization at a temperature far below the Curie temperature. Both optical training and direct switching of ferromagnetism are most effective near CI/FCI states, which we attribute to a gap enhanced valley polarization of photo-injected holes. We show that the magnetization can be dynamically switched by modulating the helicity of optical excitation. Spatially resolved measurements further demonstrate optical writing of a ferromagnetic, and thus a CI (or FCI) domain. Our work realizes precise optical control of a topological quantum many-body system with potential applications in topological spintronics, quantum memories, and creation of exotic edge states by programmable patterning of integer and fractional QAH domains.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
First submitted version on April 24th, 2025
Emergent topology of flat bands in a twisted bilayer $α$-$T_3$ lattice
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Gourab Paul, Srijata Lahiri, Kuntal Bhattacharyya, Saurabh Basu
We investigate an interesting interplay of destructive interference due to lattice geometry and band folding due to enlargement of the Brillouin zone in generating and subsequently modifying the band topology in a twisted bilayer $ \alpha$ -$ T_3$ system. The pronounced degeneracy of the emergent flat band in the dice limit of the $ \alpha$ -$ T_3$ lattice is removed on alignment with h-BN layers, resulting in the formation of sub-bands with varying topological characteristics. Remarkably, while the sub-band near charge neutrality exhibits a trivial behavior, a topologically non-degenerate singular sub-band emerges away from charge neutrality. The topological band remains isolated from the rest of the bands for a substantial area of the $ \alpha - \theta$ plane (where $ \alpha$ and $ \theta$ correspond to the hopping ratio and twist angle respectively) while exhibiting multiple phase transitions as a function of the aforementioned parameters via hybridization with its nearest bands. We study the evolution of the hybrid Wannier charge center and the Chern number to characterize the different emergent topological phases. Finally, the degree of flatness of the topological band is studied as a function of both $ \alpha$ and $ \theta$ to explicitly show the influence of quantum interference and band folding on the width of the topological band.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 7 figures
Theoretical investigation of Quantum Anomalous Hall Effect in Potassium Tri-vanadium Pentantimonide
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
The Kagome metal Potassium Tri-vanadium Pent-antimonide can support the quantum anomalous Hall effect theoretically. This is justified by flat bands and Dirac points susceptible to gap opening by spin-orbit coupling or magnetic ordering. The theoretical investigation of this quantum effect is possible exploring strategies like magnetic proximity, and strain or electric gating tuning. Our goal here is to explore the possibility of quantum anomalous Hall effect with a system Hamiltonian involving nearest-neighbour and complex next nearest-neighbour hopping, Rashba spin-orbit coupling, exchange field due to magnetic proximity, and charge density wave. Our preliminary analysis with these ingredients reveals that the system hosts multiple bands whose Chern numbers values suggest weak topological characteristics-not yet quantized, but showing signs of nontrivial Berry curvature accumulation. Upon introducing momentum-space winding, mimicking an orbital magnetic flux, through the momentum-dependence of the phase of the complex hopping, we find that two bands in the multiple band system carry opposite Chern numbers, indicating the emergence of chiral edge states and a quantized anomalous Hall effect. The rest remain trivial, but the system as a whole is no longer topologically inert.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 4 figures
Origin of Glass-like Thermal Conductivity in Crystalline TlAgTe
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Shantanu Semwal (1), Yi Xia (2), Chris Wolverton (3), Koushik Pal (1) ((1) Department of Physics, Indian Institute of Technology Kanpur, Kanpur, India (2) Department of Mechanical and Materials Engineering, Portland State University, Portland, USA (3) Department of Materials Science and Engineering, Northwestern University, Evanston, United States)
Ordered crystalline compounds exhibiting ultralow and glass-like thermal conductivity are both fundamentally and technologically important, where phonon quasi-particles dominate their heat transport. Understanding the microscopic mechanisms that govern such unusual transport behavior is necessary to unravel the complex interplay of crystal structure, phonons, and collective excitations of these quasi-particles. Here, we use state-of-the-art first-principles calculations based on quantum density functional theory to investigate the origin of experimentally measured unusually low and glassy thermal conductivity in semiconducting TlAgTe. Utilizing a unifying framework of anharmonic lattice dynamics theory that combine phonon self-energy induced frequency renormalization, particle-like Peierls ($ kappa_l^P$ ) and wave-like coherent ($ kappa_l^C$ ) thermal transport contributions including three and four-phonon scattering channels, we successfully explain the experimental results both in terms of magnitude and temperature dependence. Our analysis reveals that TlAgTe exhibits several localized phonon modes arising from concerted rattling-like vibration of Tl atoms, which show strong temperature dependence and enhanced four-phonon scattering rates that are dominated by Umklapp processes, suppressing $ kappa_l^P$ to ultralow values. The ensuing strong anharmonicity induced by local structural distortions, lone-pair electrons, and rattling-like vibrations of the heavy cations lead to a transition from particle-like behavior to wave-like tunneling characteristics of the phonon modes above 40 cm$ ^-1$ , contributing significantly to $ kappa_l^C$ which increases with temperature. Our analysis uncovers important structure-property relationship, which may be used in designing of novel materials with tunable thermal conductivity.
Materials Science (cond-mat.mtrl-sci)
Flexible orbital torque device with ultralow switching current
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Liguang Gong, Jian Song, Bin Lao, Run-Wei Li, Zhiming Wang
Orbital torque (OT) offers a highly efficient way for electrical magnetization manipulation. However, its potential in the emerging field of flexible spintronics remains largely unexplored. Here, we demonstrate a flexible and robust OT device based on a mica/SrRuO3(SRO)/CoPt heterostructure. We measure a large torque efficiency of -0.31, which originates from the significant orbital Hall effect in the SRO layer. Leveraging the low thermal conductivity of the mica substrate, a thermally-assisted switching mechanism is activated, enabling an ultralow threshold current density of 9.2x109 A/m2. This value represents a 90% reduction compared to conventional spin-torque devices and a 52% reduction against its rigid counterpart on a SrTiO3 substrate. The superior performances is well-maintained after 103 bending cycles, conforming its exceptional flexibility and durability. Our work pioneers the development of flexible OT devices, showcasing a viable path toward next-generation, low-power wearable spintronic applications.
Materials Science (cond-mat.mtrl-sci)
Room temperature giant magnetoresistance detection of spin hall nano-oscillator dynamics in synthetic antiferromagnetic Spin-Valve
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Chunhao Li, Xiaotian Zhao, Wenlong Cai, Long Liu, Wei Liu, Zhidong Zhang
Conventional spin Hall nano-oscillators (SHNOs) face fundamental power limitations due to the low anisotropic magnetoresistance (AMR < 0.3%) of ferromagnetic layers. To address this, we developed a synthetic antiferromagnetic spin-valve (SAF-SV) heterostructure [Ta/NiFe/Ru/NiFe/Cu/NiFe/Hf/Pt] that enables efficient giant magnetoresistance (GMR)-based detection of SHNO dynamics at room temperature. The NiFe/Ru/NiFe SAF reference layer, operating in the spin-flop state, couples with the NiFe free layer through a Cu spacer to achieve a remarkable GMR ratio of 0.568% - exhibiting complete independence of magnetic field/current orientation. Spin-torque ferromagnetic resonance (ST-FMR) verifies that the ferromagnetic resonance linewidth of the free layer can be effectively modulated by dc current through the Pt heavy metal layer, while maintaining decoupled dynamics from the SAF layer. Thermal management via high-thermal-conductivity SiC substrates and AlN capping layers successfully mitigates current-shunting-induced Joule heating. Notably, stable auto-oscillation peaks are observed at 820 mA bias current, with oscillation frequency tunable by external magnetic field and potential dual-mode behavior at low fields. This work establishes a new paradigm for room-temperature, high-power spintronic oscillators, offering significant potential for neuromorphic computing and coherent RF communication applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Isofrequency spin-wave imaging using color center magnetometry for magnon spintronics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Samuel Mañas-Valero, Yasmin C. Doedes, Artem Bondarenko, Michael Borst, Samer Kurdi, Thomas Poirier, James H. Edgar, Vincent Jacques, Yaroslav M. Blanter, Toeno van der Sar
Magnon spintronics aims to harness spin waves in magnetic films for information technologies. Color center magnetometry is a promising tool for imaging spin waves, using electronic spins associated with atomic defects in solid-state materials as sensors. However, two main limitations persist: the magnetic fields required for spin-wave control detune the sensor-spin detection frequency, and this frequency is further restricted by the color center nature. Here, we overcome these limitations by decoupling the sensor spins from the spin-wave control fields -selecting color centers with intrinsic anisotropy axes orthogonal to the film magnetization- and by using color centers in diamond and hexagonal boron nitride to operate at complementary frequencies. We demonstrate isofrequency imaging of field-controlled spin waves in a magnetic half-plane and show how intrinsic magnetic anisotropies trigger bistable spin textures that govern spin-wave transport at device edges. Our results establish color center magnetometry as a versatile tool for advancing spin-wave technologies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
5 figures + supplement
Chemical control of polymorphism and ferroelectricity in PbTiO3 and SrTiO3 monolayers and bilayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Shaowen Xu, Jeffrey R. Reimers, Fanhao Jia, Wei Ren
Layers of perovskites, found in 3D materials, 2D heterostructures, and nanotubes, often distort from high symmetry to facilitate dipole polarisation that is exploitable in many applications. Using density-functional theory calculations, ferroelectricity in bilayers of the 2D materials PbTiO3 and SrTiO3 is shown to be controlled by bond breakage and formation processes that act as binary switches. These stacking-dependent processes turn on and off as a function of relaxation from high-symmetry structures and the application of biaxial strain, and their concerted rearrangements lead to low energy barriers for ferroelectric polarisation switching. Structures with symmetry intermediate between high-symmetry octahedral forms and low-symmetry ferroelectric forms are identified, allowing the intrinsic processes associated with traditional “ferrodistortive” and “antiferrodistortive” distortions of TiO6 octahedra to be identified. Ferrodistortive-mode activity is shown to be generated by the simultaneous application of two different types of curvilinear antiferrodistortive motions. In this way, four angular variabes control polarisation switching through the concerted making and breaking of chemical bonds. These subltities make the polarisation sensitive to chemical-environment and temperature effects that manipulate strain and structure, features exploitable in futuristic devices.
Materials Science (cond-mat.mtrl-sci)
Self-similarity in creeping salt crystallization
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-27 20:00 EDT
R.J. Wijnhorst, M. Prat, N. Shahidzadeh
The self-amplifying creeping of salts can produce striking macroscopic structures, such as desert roses in arid regions and salt pillars near saline lakes. While these formations are visually remarkable, salt crystallization, often seen as efflorescence on surfaces, also poses significant challenges for cultural heritage conservation, materials science, and soil management. In this study, we investigate the mechanisms underlying self-organized crystallization within efflorescence deposits. Our findings reveal that these porous salt deposits exhibit pronounced self-similarity, with the crystallization process recurring at multiple length scales. This results in smaller replicas of the overall structure nested within larger ones, creating fractal geometries similar to those found in cauliflower and broccoli. By performing controlled evaporation experiments and microscale analysis using advanced imaging techniques combined with fractal dimension analysis, we uncover the hierarchical and size-controlled precipitation of cubic microcrystals within the porous efflorescence. Furthermore, we develop a hierarchical growth model demonstrating that the ultimate height of the macroscopic salt deposit is primarily determined by the initial mass of salt, rather than by the interplay of capillary and viscous forces when salt solution flows within the porous salt structure.
Soft Condensed Matter (cond-mat.soft), Applied Physics (physics.app-ph)
Locally tuned hydrodynamics of active polymer chains
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-27 20:00 EDT
Lisa Sappl, Christos N. Likos, Andreas Zöttl
We employ mesoscopic simulations to study active polymers in a solvent via multi-particle collision dynamics. We investigate linear chains in which either the head or tail monomer exerts an active force, directed away from or towards its neighbor, respectively, while the remaining monomers are passive. We find that, in contrast to flexible chains, for stiff chains the position of the active monomer has minimal influence on both the structural and dynamic properties of the chain. An active head monomer pulls the chain behind it, straightening the backbone – an effect that can be interpreted as activity-induced stiffening. In contrast, an active tail pushes into the chain, causing crumpling. This leads to faster decorrelation of the polymer backbone over time, rendering the active motion less persistent. These effects occur regardless of whether hydrodynamic interactions are included or not. Hydrodynamics is included by the imposition of a local counter-force in the surrounding fluid, as opposed to distributing the former equally to all fluid elements. By specifying the position of this counterforce onto the fluid, we can tune the hydrodynamic flow fields of the active polymers being both contractile and extensile. Interestingly, the emerging pusher- and puller flow fields are strongly influenced by the force propagation inside the polymer chain.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph), Computational Physics (physics.comp-ph)
16 pages, 12 figures
Itinerant and topological excitations in a honeycomb spiral spin liquid candidate
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-27 20:00 EDT
Yuqian Zhao, Xuping Yao, Xun Chen, Zongtang Wan, Zhaohua Ma, Xiaochen Hong, Yuesheng Li
The frustrated insulating magnet can stabilize a spiral spin liquid, arising from cooperative fluctuations among a subextensively degenerate manifold of spiral configurations, with ground-state wave vectors forming a continuous contour or surface in reciprocal space. The atomic-mixing-free honeycomb antiferromagnet GdZnPO has recently emerged as a promising spiral spin-liquid candidate, hosting nontrivial topological excitations. Despite growing interest, the transport and topological properties of spiral spin liquids remain largely unexplored experimentally. Here, we report transport measurements on high-quality, electrically insulating GdZnPO single crystals. We observe a giant low-temperature magnetic thermal conductivity down to $ \sim$ 50 mK, described by $ \kappa_{xx}^\mathrm{m}$ $ \sim$ $ \kappa_0+\kappa_1T$ , where both $ \kappa_0$ and $ \kappa_1$ are positive constants associated with excitations along and off the spiral contour in reciprocal space, respectively. This behavior parallels the magnetic specific heat, underscoring the presence of mobile low-energy excitations intrinsic to the putative spiral spin liquid. Furthermore, the observed positive thermal Hall effect confirms the topological nature of at least some of these excitations. Our findings provide key insights into the itinerant and topological properties of low-lying spin excitations in the spiral spin-liquid candidate.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
accepted in Nature Communications. Supporting Information is available from the authors
In silico investigation of Ba-based ternary chalcogenides for photovoltaic applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Ramya Kormath Madam Raghupathy, Hossein Mirhosseini, Thomas D. Kühne
In solar cells, the absorbers are the key components for capturing solar energy and converting photons into electron-hole pairs. The search for high-performance absorbers with advantageous characteristics is an ongoing task for researchers. In this work, we investigated promising and environmentally benign Ba-based ternary chalcogenides for photovoltaic applications. The total number of Ba-based ternary chalcogenides in the Materials Project database was found to be 279. Materials screening based on bandgap size and stability reduced the number of compounds to 19. The performance of an absorber depends on the charge carrier lifetime, which is controlled by non-radiative processes involving defects. Hence, we investigated the intrinsic defects and p-type dopability of the compounds. We identified two Ba-based compounds, namely \ch{BaCu2Se2} and \ch{ZrBaSe3}, as promising absorbers for single-junction and tandem cells and investigated them in detail.
Materials Science (cond-mat.mtrl-sci)
Weighted Hartree-Fock-Bogoliubov method for interacting fermions: An application to ultracold Fermi superfluids
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-27 20:00 EDT
Nikolai Kaschewski, Axel Pelster, Carlos A. R. Sá de Melo
For several decades it has been known that divergences arise in the ground-state energy and chemical potential of unitary superfluids, where the scattering length diverges, due to particle-hole scattering. Leading textbooks and research articles recognize that there are serious issues but ignore them due to the lack of an approach that can regularize these divergences. We find a solution to this difficulty by proposing a general method, called the weighted Hartree-Fock-Bogoliubov theory, to handle multiple decomposition channels originating from the same interaction. We distribute the interaction in weighted channels determined by minimization of the action, and we apply this idea to unpolarized Fermi superfluids. Using our method, we solve a long-standing difficulty in the partitioning of the interaction into Hartree, Fock, and Bogoliubov channels for Fermi superfluids, and we obtain a phase diagram at the saddle-point level, which contains multichannel nonperturbative corrections. In particular, we find a previously overlooked superfluid phase for weak interactions, which is dominated by particle-hole processes, in addition to the usual superfluid phase only containing particle-particle physics.
Quantum Gases (cond-mat.quant-gas), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
26 pages, 12 figures
Phys. Rev. Research 7, 033186 (2025)
Temperature-Aware Recurrent Neural Operator for Temperature-Dependent Anisotropic Plasticity in HCP Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Yannick Hollenweger, Dennis M. Kochman, Burigede Liu
Neural network surrogate models for constitutive laws in computational mechanics have been in use for some time. In plasticity, these models often rely on gated recurrent units (GRUs) or long short-term memory (LSTM) cells, which excel at capturing path-dependent phenomena. However, they suffer from long training times and time-resolution-dependent predictions that extrapolate poorly. Moreover, most existing surrogates for macro- or mesoscopic plasticity handle only relatively simple material behavior. To overcome these limitations, we introduce the Temperature-Aware Recurrent Neural Operator (TRNO), a time-resolution-independent neural architecture. We apply the TRNO to model the temperature-dependent plastic response of polycrystalline magnesium, which shows strong plastic anisotropy and thermal sensitivity. The TRNO achieves high predictive accuracy and generalizes effectively across diverse loading cases, temperatures, and time resolutions. It also outperforms conventional GRU and LSTM models in training efficiency and predictive performance. Finally, we demonstrate multiscale simulations with the TRNO, yielding a speedup of at least three orders of magnitude over traditional constitutive models.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
Quantum geometry in low-energy linear and nonlinear optical responses of magnetic Rashba semiconductor (Ge,Mn)Te
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Tsubasa Takagi, Hikaru Watanabe, Ryutaro Yoshimi, Yuki Sato, Shingo Toyoda, Atsushi Tsukazaki, Kei S. Takahashi, Masashi Kawasaki, Yoshinori Tokura, Naoki Ogawa
Quantum geometry appears as a key factor in understanding the optical properties of quantum materials, with the anticipation on diverging or quantized responses near the Dirac and Weyl points. Here we investigate linear and nonlinear optical responses-optical conductivity and injection current- in a magnetic Rashba semiconductor in the mid-infrared region, with varying the Fermi energy across the Dirac point. We reveal that the linear optical conductivity reflects quantum metric, which remains finite irrespective of the diminishing joint density-of-states at lower photon energy. It is also confirmed that the magnetic injection current enhances depending on the energy of the Fermi level relative to the Dirac point. These optical spectra are nicely reproduced by our theoretical calculations with geometrical effects taken into account.
Materials Science (cond-mat.mtrl-sci)
Kolmogorov-type non-thermal fixed points and beyond of far-from-equilibrium dilute system: ultra-cold Fermi gas
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-27 20:00 EDT
The far-from-equilibrium dynamics driven by the scattering from next-to-leading-order (NLO) corrections in the quantum field theory has stationary solutions for the particle distribution characterized as the Kolmogorov-type non-thermal fixed points. The dynamics of the spatially homogeneous, isotropic dilute ultra-cold Fermi gas is investigated, and its kinetic equation confirms the Kolmogorov-type non-thermal fixed points in the perturbation theory by the quasi-particle assumption, in contrast to the wave turbulence of the weakly coupled ultra-cold Bose gas. In addition, other stationary states are found without the quasi-particle assumption and in a strongly coupled system. These analytical solutions provide chances for future experiments and numerical simulations in search of far-from-equilibrium stationary states of the dilute system.
Quantum Gases (cond-mat.quant-gas), Other Condensed Matter (cond-mat.other), High Energy Physics - Phenomenology (hep-ph)
10 pages
Single-Photon Detection in Few-Layer NbSe$_2$ Superconducting Nanowires
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-27 20:00 EDT
Lucio Zugliani, Alessandro Palermo, Bianca Scaparra, Aniket Patra, Fabian Wietschorke, Pietro Metuh, Athanasios Paralikis, Domenico De Fazio, Christoph Kastl, Rasmus Flaschmann, Battulga Munkhbat, Kai Müller, Jonathan J. Finley, Matteo Barbone
Superconducting Nanowire Single-Photon Detectors (SNSPDs) are key building blocks for photonic quantum technologies due to their ability to detect single photons with ultra-high efficiency, low dark counts and fast temporal resolution. Superconducting materials exhibiting high uniformity, large absorption cross-section and atomic-scale thickness are desirable to extend single-photon detection from the near-infrared up to the terahertz regime, where existing material choices are especially constrained. Substrate independence would further open the way to integrate detectors onto functional materials and heterostructures, enhancing performance and enabling proximal read-out of a wide range of individual excitations. Here, we top-down shape the prototypical two-dimensional superconductor niobium diselenide (NbSe$ _2$ ) into few-layer nanowires less than 100 nm wide and demonstrate single-photon detection at 780 and 1550 nm. At the same time, the dark-count rate remains below 1 Hz up to the switching current and we achieve a timing jitter below 50 ps. We use a diffusive hot-spot model to estimate a theoretical cut-off wavelength that surpasses the millimetre range. Our results open up routes toward quantum limited detectors integrated into quantum-photonic circuits and quantum devices, with the potential for novel detection capabilities and unprecedented energy sensitivity.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
12 pages
Designing Antiferromagnetic Spin-1/2 Chains in Janus Fullerene Nanoribbons
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
We computationally design antiferromagnetic spin-1/2 chains in fullerene nanoribbons by introducing extra C$ _{60}$ cages at one of their edges. The resulting odd number of intermolecular bonds induces an unpaired $ \pi$ -electron and hence a quantised magnetic moment in otherwise non-magnetic nanoribbons. We further reveal the formation of an antiferromagnetic ground state upon the linear arrangement of spin-$ 1/2$ C$ _{60}$ cages that is insensitive to the specific structural motifs. Compared with graphene nanoribbons, Janus fullerene nanoribbons may offer an experimentally more accessible route to magnetic edge states with atomic precision in low-dimensional carbon nanostructures, possibly serving as a versatile nanoarchitecture for scalable spin-based devices and the exploration of many-body quantum phases.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph), Atomic and Molecular Clusters (physics.atm-clus), Chemical Physics (physics.chem-ph)
7 pages, 3 figures
Striking Similarities in Dynamics and Vibrations of 2D Quasicrystals and Supercooled Liquids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-27 20:00 EDT
Edwin A. Bedolla-Montiel, Marjolein Dijkstra
We investigate the interplay between structure and dynamics in two structurally distinct two-dimensional systems: a dodecagonal quasicrystal (DDQC) and a supercooled binary liquid. Using molecular dynamics simulations, we uncover striking dynamical similarities despite their fundamentally different structural organizations. Both systems exhibit pronounced dynamic heterogeneities, as evidenced by the cage-trapping plateaus in the mean-squared displacement and the pronounced peaks in the non-Gaussian parameter. In both cases, we observe a strong correlation between local structural order and dynamic propensity, indicating similar structure-dynamics relationships, albeit driven by distinct microscopic mechanisms. Despite these parallels, their vibrational properties diverge: the DDQC exhibits multiple peaks linked to phason dynamics, while the supercooled liquid displays a characteristic boson peak. Analysis of vibrational eigenmodes shows that both systems exhibit extended modes at low frequencies. At high frequencies, however, the DDQC maintains a higher density of topological defects, reflecting its quasi-long-range order. Finally, we contextualize these findings by comparing both systems to a square crystal. While the dynamics appears similar across all three systems, the vibrational and topological features clearly distinguish the DDQC and glass from the crystalline state. These results underscore a surprising universality in dynamical behavior across structurally diverse systems and provide new insights into how structural organization shapes motion in soft-matter systems.
Soft Condensed Matter (cond-mat.soft)
19 pages, 14 figures
Strong and Engineerable Optical Anisotropy in Easily Integrable Epitaxial SrO(SrTiO 3 ) N Ruddlesden–Popper Thin Layers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Mohamed Oussama Bounab (INL - MFN), Clarisse Furgeaud (INL - MFN), Sébastien Cueff (INL, INL - I-Lum), Lotfi Berguiga (INL - I-Lum), Romain Bachelet (INL - MFN), Mohamed Bouras, Laurent Pedesseau (FOTON), Jacky Even (INSA Rennes, FOTON), Ludovic Largeau (C2N), Guillaume Saint-Girons (INL - MFN)
Optical anisotropy is a key property for numerous photonic devices. However, bulk anisotropic materials suitable for such applications remain relatively scarse and are often challenging to synthesize as thin films. Additionally, the optical losses as well as the complex structuration of anisotropic metamaterials hinder their integrability in photonic devices. Based on ellipsometry measurements coupled with reflectance, it is demonstrated here that Ruddlesden-Popper (RP) SrO(SrTiO 3 ) N phases (STO-RP N ), epitaxial thin films composed of a SrTiO 3 lattice periodically interrupted by one SrO atomic plane every N unit cells, exhibit pronounced dichroism and birefringence over a broad spectral range. Notably, this anisotropy is tunable by adjusting the RP order N. In contrast to most other anisotropic materials reported in the literature, STO-RP N thin layers can be fabricated using industry-standard growth processes. As it can be epitaxially grown on Si and GaAs using SrTiO 3 templates, the work paves the way for their compact integration on these photonic platforms.
Materials Science (cond-mat.mtrl-sci)
Advanced Optical Materials, 2025
Microscale optoelectronic synapses with switchable photocurrent from halide perovskite
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Jeroen J. de Boer, Agustin O. Alvarez, Moritz C. Schmidt, Dimitrios Sitaridis, Bruno Ehrler
Efficient visual data processing by neuromorphic networks requires volatile artificial synapses that detect and process light inputs, ideally in the same device. Here, we demonstrate microscale back-contacted optoelectronic halide perovskite artificial synapses that leverage ion migration induced by a bias voltage to modulate their photocurrent. The photocurrent changes are due to the accumulation of mobile ions, which induces a transient electric field in the perovskite. The photocurrent changes are volatile, decaying on the order of seconds. The photocurrent changes can be controlled by both the applied voltage and illumination. The symmetric device supports changing of the photocurrent polarity, switching between inhibitory and exhibitory functioning. The photocurrent can be updated by spike-timing-dependent plasticity (STDP)-learning rules inspired by biology. We show with simulations how this could be exploited as an attention mechanism in a neuromorphic detector. Our fabrication procedure is compatible with high-density integration with CMOS and memristive neuromorphic networks for energy-efficient visual data processing inspired by the brain.
Materials Science (cond-mat.mtrl-sci)
Stochastic Forces Enhance Tracer Diffusion in Non-motile Active Matter
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-27 20:00 EDT
Henry Alston, Raphael Voituriez, Thibault Bertrand
Stochasticity is a defining feature of the pairwise forces governing interactions in biological systems-from molecular motors to cell-cell adhesion-yet its consequences on large-scale dynamics remain poorly understood. Here, we show that reciprocal but randomly fluctuating interactions between particles create active suspensions which can enhance the diffusion of an external tracer particle, even in the absence of self-propulsion or non-reciprocity. Starting from a lattice model with pairwise dynamics that minimally break detailed balance, we derive a coarse-grained dynamical theory for spatio-temporal density fluctuations and reveal an elevated effective temperature at short wavelengths. We then compute the self-diffusion coefficient of a tracer particle weakly coupled to our active fluid, demonstrating that purely reciprocal stochastic interactions provide a distinct and generic route to enhanced diffusivity in dense non-equilibrium suspensions.
Soft Condensed Matter (cond-mat.soft)
7+9 pages, 5 figures
Non-Exponential Relaxation in the Rotating Frame of a Driven Nanomechanical Mode
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Hyunjin Choi, Oriel Shoshani, Ryundon Kim, Younghun Ryu, Jinhoon Jeong, Junho Suh, Steven W. Shaw, M. I. Dykman, Hyoungsoon Choi
We present direct observation of the ring-down dynamics in the rotating frame of a resonantly driven single-mode nonlinear nanomechanical resonator. An additional close to resonance harmonic force excites nonlinear oscillations about the fixed point in the rotating frame. When the secondary drive is removed, we measure decay of the in-phase and quadrature components toward this fixed point. We show that the decay of the in-phase signal is non-exponential, even though the vibration amplitude decays exponentially if both forces are switched off. A minimalistic model captures these dynamics as well as the spectrum of the vibrations excited by the additional force, relating them to the dissipation-induced symmetry breaking of the dynamics in the rotating frame.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 4 figures with supplemental material (9 pages, 5 figures)
3D Strain Field Reconstruction by Inversion of Dynamical Scattering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Laura Niermann, Tore Niermann, Chengyu Song, Colin Ophus
Strain governs not only the mechanical response of materials but also their electronic, optical, and catalytic properties. For this reason, the measurement of the 3D strain field is crucial for a detailed understanding and for further developments of material properties through strain engineering. However, measuring strain variations along the electron beam direction has remained a major challenge for (scanning-) transmission electron microscopy (S/TEM). In this article, we present a method for 3D strain field determination using 4D-STEM. The method is based on the inversion of dynamical diffraction effects, which occur at strain field variations along the beam direction. We test the method against simulated data with a known ground truth and demonstrate its application to an experimental 4D-STEM dataset from an inclined pseudomorphically grown Al$ _{0.47}$ Ga$ _{0.53}$ N layer.
Materials Science (cond-mat.mtrl-sci)
The article has been submitted to Applied Physics Letters
A comparative nanotribological investigation on amorphous and polycrystalline forms of MoS2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Hesam Khaksar, Prashant Mittal, Nabil Daghbouj, Grzegorz Cios, Tomas Polcar, Enrico Gnecco
The wear behavior of two amorphous and polycrystalline forms of MoS2 prepared by magnetron sputtering has been characterized in a combined nanoindentation and atomic force microscopy study. From the analysis of the depth and width of wear tracks estimated after scratching the surfaces with a Berkovich indenter and a loading force up to 2 mN, we conclude that both forms follow the Archard wear equation, and the wear resistance is about four times higher on the amorphous MoS2. Moreover, a comparison of lateral force maps on pristine and worn areas shows a considerable reduction of friction on both forms, which is possibly due to the significant smoothing of the surfaces caused by scratching. With normal forces in the micro N range, the analysis is made difficult by the fact that the linear dimensions of the wear tracks are comparable to those of the granular structures forming the surfaces. Even if the Archard equation could not be tested in this case, the wear resistance is considerably larger on amorphous MoS2 also on the nanoscale. In this way, our results disclose information on the nanotribology of MoS2 thin films in forms different from the layered structures commonly discussed in the literature. The amorphous form outperforms the polycrystalline one.
Materials Science (cond-mat.mtrl-sci)
Exploring nanoscale metallic multilayer Ta/Cu films: Structure and some insights on deformation and strengthening mechanisms
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Daniel Karpinski, Tomas Polcar, Andrey Bondarev
Nanoscale metallic multilayer (NMM) films are systems offering insight into the role of interfaces in metal plasticity, deformation, and strengthening mechanisms. Magnetron sputtering was used to fabricate the Ta-Cu NMM films with a periodicity (equal Ta and Cu layer thickness) from 6 to 80 nm, with resulting structure exhibiting strongly incoherent tetragonal beta-Ta and face-centered cubic Cu phase. The high-load indentation test, TEM studies, and the rCLS model collectively demonstrate that all NMM films predominantly undergo plastic deformation. This plastic deformation primarily occurs within the soft Cu layer, while the propagation of dislocations across the incoherent interface is largely excluded.
Materials Science (cond-mat.mtrl-sci)
Localized and delocalized modes on random geometric graphs in 1D
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-08-27 20:00 EDT
Luca Schaefer, Barbara Drossel
We perform an extensive investigation of the localization properties of the eigenmodes of the Laplace and adjacency matrix for one-dimensional random geometric graphs. We evaluate the density of states, the probability distribution of the participation ratio and its relation to the eigenvalue. By disentangling the influence of system size, graph component size distribution, mean degree of nodes, network motifs, and degeneracy, we provide a comprehensive understanding of this system. We compare our findings to ordered graphs with the same mean degree and to one-dimensional tight-binding models.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
Mass-induced Coulomb drag in capacitively coupled superconducting nanowires
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Aleksandr Latyshev, Adrien Tomà, Eugene V. Sukhorukov
We investigate Coulomb drag in a system of two capacitively coupled superconducting nanowires. In this context, drag refers to the appearance of a stationary voltage in the passive wire in response to a current bias applied to the active one. Quantum phase slips (QPS) in the biased wire generate voltage fluctuations that can be transmitted to the other. Using perturbative and semiclassical approaches, we show that when both wires are superconducting the induced voltage vanishes due to exact cancellation of plasmon contributions. By contrast, when the second wire is tuned below the superconductor-insulator transition and develops a mass gap, this cancellation is lifted and a finite drag voltage emerges. The drag coefficient exhibits a crossover from weak drag in short wires to a maximal value set by the mutual capacitance in long wires. A semiclassical picture of voltage pulse propagation clarifies the physical origin of the effect: the mass term synchronizes plasmon modes and prevents complete cancellation of induced signals. Our results establish a mechanism of mass-induced Coulomb drag in low-dimensional superconductors and suggest new routes for probing nonlocal transport near quantum criticality.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Shubnikov-de Haas oscillations and planar Hall effect in HfTe2
New Submission | Other Condensed Matter (cond-mat.other) | 2025-08-27 20:00 EDT
Qixuan Li, Gangjian Jin, Nannan Tang, Bin Wang, Bing Shen, Donghui Guo, Dingyong Zhong, Huakun Zuo, Huichao Wang
Layered transition-metal dichalcogenide (TMD) HfTe2 is a topological semimetal candidate with increasing attentions recently. The map of the Fermi surface is of interest and importance to understand its properties. Here we present a study of Shubnikov-de Haas (SdH) oscillations and planar Hall effect (PHE) in HfTe2. The single crystals grown by flux method show the largest unsaturated magnetoresistance (MR) effect of 1.1\ast104 % at 14 T and 2 K. The angle-resolved SdH oscillations reveal that the Fermi surface consists of three pockets with different anisotropy. In addition, we observe PHE and anisotropic MR (AMR) effect in the material for a wide temperature range. The effective mass, carrier density and quantum transport mobility are quantified in the system, and the Berry phase is discussed. Our work provides crucial insights into the electronic structure and the Fermi surface of the semimetal.
Other Condensed Matter (cond-mat.other), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Polarity-dependent Electroadhesion at Silicon Interfaces with Nanoscale Roughness
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-27 20:00 EDT
Liang Peng, Stefan Kooij, HT Ciftci, Daniel Bonn, Bart Weber
We measure and model electroadhesion across multi-asperity silicon interfaces with nanometer scale roughness. When electrically biased, our naturally oxidized silicon interfaces display a leakage current consistent with the Fowler-Nordheim model and electroadhesion that can be successfully captured using a boundary element contact model. We show that polysilicon exhibits electroadhesion only under positive bias applied to the substrate monocrystalline wafer, which we interpret as a result of the reduced mobility of holes, with respect to electrons, within polysilicon. Overall, our findings reveal that electrostatic interactions can significantly enhance adhesion and friction between stiff and smooth surfaces, which can be important for example in precision positioning applications.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
Linear approximations of large deviations: Cubic diffusion test
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-27 20:00 EDT
Pelerine Tsobgni Nyawo, Hugo Touchette
We propose a method for approximating the large deviation rate function of time-integrated observables of diffusion processes, used in statistical physics to characterize the fluctuations of nonequilibrium systems. The method is based on linearizing the effective process associated with the large deviations of the process and observable considered, and is tested for a simple one-dimensional nonlinear diffusion model involving a cubic drift. The results show that the linear approximation compares well with the exact rate function, especially in the large fluctuation regime, and that its accuracy is related to the way the linearized process localizes in space. Possible extensions and applications to more complex diffusion models are proposed for future work.
Statistical Mechanics (cond-mat.stat-mech)
8 pages, 3 figures
Junctional-Fluctuation-Mediated Fluidisation of Multi-Phase Field Epithelial Monolayers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-27 20:00 EDT
We analyse a multi-phase field model for an epithelial monolayer with pairwise adhesions between neighbouring cells following an Ornstein-Uhlenbeck process, representing the stochastic turnover of junctional molecular motors. These fluctuations in junctional adhesion result in rearrangements in the tissue, fluidising it and producing diffusive cell motion. Similar junctional fluctuations have proven a very useful tool in the vertex model literature, and we hope they will be equally helpful to the multi-phase field model approach. Moreover, we observe that the cells’ effective diffusion coefficient depends non-monotonically on the persistence time of the fluctuations, confirming results previously observed in the vertex model.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Channel flows of deformable nematics
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-27 20:00 EDT
Ioannis Hadjifrangiskou, Sumesh P. Thampi, Julia M. Yeomans
We describe channel flows in a continuum model of deformable nematic particles. In a simple shear flow, deformability leads to a nonlinear coupling of strain rate and vorticity, and results in shape oscillations or flow alignment. The final steady state can depend on initial conditions, and we explain this behaviour by considering a phase space representation of the dynamics. In Poiseuille flow, particle deformability and nematic elasticity induce banding, where particles near the walls are aligned, and those near the centre of the channel oscillate in direction and shape. Our results show that particle deformability can lead to complex behaviour even in simple flows, suggesting new microfluidic experiments.
Soft Condensed Matter (cond-mat.soft)
Density-Velocity Relation Is Scale-Dependent in Epithelial Monolayers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-27 20:00 EDT
Hengdong Lu, Tianxiang Ma, Amin Doostmohammadi
The relationship between cell density and velocity is often assumed to be negative, reflecting crowding-induced suppression of movement. However, observations across systems reveal a more nuanced picture: while some emphasize contact inhibition of locomotion, others suggest that dense regions exhibit enhanced activity due to force generation and stress buildup. Here, using experimental measurements we show that density-velocity relations in epithelial monolayers are inherently scale dependent. By coarse-graining cell trajectories over multiple spatial windows, we find that cell velocity correlates positively with local density at small scales, but negatively at large scales. Employing traction force measurements, we find that this crossover coincides with the emergence of mechanical pressure segregation, defining a characteristic length scale beyond which crowding dominates. A minimal model incorporating activity-induced shape changes reproduces this crossover and identifies the competition between active force generation and mechanical confinement as the underlying mechanism. Our results reconcile conflicting views of density-regulated migration and highlight an emergent length scale as a key factor in interpreting collective cell dynamics.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
9 pages, 5 figures
Giant octupole moment in magnetic multilayers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Chang Niu, Lulu Li, Yiqing Wang, Lei Wang, Ke Xia
Multipole moments serve as order parameters for characterizing higher-order magnetic effects in momentum space, providing a framework to describe diverse magnetic responses by extending the concept of magnetism. In this letter, we introduce a methodology to quantitatively determine the multipole moment contributions in anomalous Hall effect through angle-dependent anomalous Hall current, with explicit incorporation of discrete crystal symmetries. Our technique uniquely enables the investigation of octupole contribution in non-periodic systems, particularly at interfaces and surfaces. Typically, in (Ag$ _{2}$ Fe$ _{5}$ )$ _{n}$ multilayers with quantum-well-engineered $ k$ -point selectivity, we observe an octupole-dominated anomalous Hall effect in conventional ferromagnetic materials, through first-principles calculations. These results fundamentally challenge the existing theoretical understanding of the anomalous Hall effect, showing that even the conventional contribution arises not only from the dipole moment (net magnetization). Furthermore, we establish practical control over the octupole contribution through two distinct approaches: interface engineering and magnetic ordering reconfiguration, opening new possibilities for manipulating higher-order transport effects.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
On the role played by electrons in the stress-strain curves of ideal crystalline solids
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Margherita Marsili, Elisa Damiani, Davide Dalle Ave, Gabriele Losi, M. Clelia Righi
The mechanical properties of a solid, which relate its deformation to external applied forces, are key factors in enabling or disabling the use of an otherwise optimal material in any application, strongly influencing also its service lifetime. Intrinsic crystal deformation mechanisms, investigated experimentally on single crystals with low dislocation densities, have been studied theoretically through atomistic simulations, mainly focusing on lattice-induced instabilities. Here, instead, we employ density functional theory and a thermodynamic analysis to probe and analyze the way in which the electronic charge of crystalline solids (Cu, Al and diamond) responds to uniaxial strain and affects their mechanical properties. Indeed, despite the very simple nature of our models, and in the presence of minimal atomic displacements, we find that the stress strain curves of Cu and Al deviate from a simple linear elastic behavior. Within a thermodynamics perspective, the features of such curves can be interpreted in terms of first and second order phase transitions. Within a thermodynamics perspective, the features of such curves can be interpreted in terms of first and second order phase transitions, which originate from Van-Hove singularities of the electronic density of states crossing the Fermi level and electron redistribution within the solid, respectively.
Materials Science (cond-mat.mtrl-sci)
YSGAG: The Ideal Substrate for YIG in Quantum Magnonics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Rostyslav O. Serha, Carsten Dubs, Christo Guguschev, Bernd Aichner, David Schmoll, Jaganandha Panda, Matthias Weiler, Philipp Pirro, Michal Urbánek, Andrii V. Chumak
Quantum magnonics leverages the quantum mechanical properties of magnons for advancing nanoscale quantum information technologies. Ferrimagnetic yttrium iron garnet (YIG), known for its exceptionally long magnon lifetimes, is a cornerstone material for magnonics and is typically grown into thin films on gadolinium gallium garnet (GGG) substrates due to near-perfect lattice matching. However, the paramagnetic nature of GGG introduces damping mechanisms detrimental to quantum applications at low temperatures. Here, we present a study of magnetic damping in a 150$ ,$ nm-thick YIG film grown on a 500$ ,\mu$ m-thick yttrium scandium gallium aluminium garnet (YSGAG) substrate, a newly developed diamagnetic alternative to GGG. Using ferromagnetic resonance (FMR) spectroscopy at temperatures as low as 30$ ,$ mK, we compare the damping characteristics of the YIG/YSGAG system with those of a conventional YIG/GGG reference system. Our results demonstrate that the YIG/YSGAG system maintains low magnetic damping from room temperature, with $ \alpha = 4.29\times10^{-5}$ , which is the lowest value reported so far for YIG/GGG films and comparable to the best YIG bulk material, and down to 30$ ,$ mK, with no significant temperature-dependent increase in damping. In this substrate, the low-temperature damping mechanisms associated with paramagnetic spins, prominent in GGG, are effectively eliminated. Consequently, YSGAG serves as an ideal substrate for YIG films in quantum magnonics and is paving the way for the development of spin-wave-based quantum technologies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Other Condensed Matter (cond-mat.other)
Optical control over topological Chern number in moiré materials
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Olivier Huber, Kilian Kuhlbrodt, Eric Anderson, Weijie Li, Kenji Watanabe, Takashi Taniguchi, Martin Kroner, Xiaodong Xu, Atac Imamoglu, Tomasz Smolenski
Controlling quantum matter with light offers a promising route to dynamically tune its many-body properties, ranging from band topology to superconductivity. However, achieving such optical control for strongly correlated electron systems in the steady-state has remained elusive. Here, we demonstrate all-optical switching of the spin-valley degree of freedom of itinerant ferromagnets in twisted MoTe2 homobilayers. This system uniquely features flat valley-contrasting Chern bands and exhibits a range of strongly correlated phases at various moiré lattice fillings, including Chern insulators and ferromagnetic metals. We show that the spin-valley orientation of all of these phases can be dynamically reversed by resonantly exciting the attractive polaron transition with circularly-polarized light. These findings not only constitute the first direct evidence for non-thermal switching of a ferromagnetic spin state at zero magnetic field, but also demonstrate the possibility of dynamical control over topological order parameter, paving the way for all-optical generation of chiral edge modes and topological quantum circuits.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 4 figures
Quantum diatomic chain: a supersolid structure in three-component Bose mixture
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-27 20:00 EDT
The formation and properties of a supersolid structure in a three-component ultracold Bose gas mixture at T=0 are investigated theoretically. The system consists of 23Na, 39K, and 41K atomic species, in which the binary mixtures of (23Na,39K) and (39K,41K) can form self-bound quantum droplets stabilized by quantum fluctuations. Two such droplets can bind together by the shared 39K component, forming a stable “dimer” structure, which displays vibrational modes analogous to a classical diatomic molecule. A simple protocol is proposed to create a stable linear chain formed by periodic repetition of this basic building block, i.e. an alternating sequence of (23Na,39K) and (39K,41K) droplets. This structure exhibits both periodic density modulations from the droplet ordering and global phase coherence due to the shared 39K component, satisfying the criteria for supersolidity, and therefore adding another system to the gallery of supersolid structures in cold atoms arena. The low-energy excitation spectrum, probed by density perturbations, identifies modes corresponding to droplet vibrations close to the ones expected from a classical diatomic chain.
Quantum Gases (cond-mat.quant-gas)
10 pages, 11 figures
Tunneling spectroscopy of the spinon-Kondo effect in one-dimensional Mott insulators
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-27 20:00 EDT
Rodrigo G. Pereira, Bruno F. Marquez, Karen Hallberg, Tim Bauer, Reinhold Egger
We study the tunneling density of states (TDOS) in one-dimensional Mott insulators at energies below the charge gap. By employing nonlinear Luttinger liquid theory and density-matrix renormalization group (DMRG) simulations, we predict that in the presence of a magnetic impurity at the boundary, characteristic Fermi-edge singularity features can appear at subgap energies in the TDOS near the boundary. In contrast to the Kondo effect in a metal, these resonances are strongly asymmetric and of power-law form. The power-law exponent is universal and determined by the spinon-Kondo effect.
Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 5 figures
Thermoelectric evidence of the electronic structure changes from the charge-density-wave transition in FeGe
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-27 20:00 EDT
Kaila Jenkins, Yuan Zhu, Dechen Zhang, Guoxin Zheng, Kuan-Wen Chen, Aaron Chan, Sijie Xu, Mason L. Klemm, Bin Gao, Ming Yi, Pengcheng Dai, Lu Li
Kagome metals provide a material platform for probing new correlated quantum phenomena due to the naturally incorporated linear dispersions, flat bands, and Van Hove singularities in their electronic structures. Among these quantum phenomena is the charge density wave (CDW), or the distortion of the lattice structure due to the motion of correlated electrons through the material. CDWs lower the energy of the compound, creating an energy gap that facilitates behaviors akin to superconductivity, nonlinear transport, or other quantum correlated phenomena. The kagome metal FeGe has been shown to host a CDW transition at approximately 100 K, and its occurrence is strongly influenced by the sample annealing conditions. However, a notable gap in the literature is the lack of clear thermoelectric transport evidence for electronic structure changes associated with this CDW transition. Here we present evidence of electron behavior modification due to annealing disorder via thermoelectric measurements on FeGe crystals presenting a CDW transition and those without a CDW. The observed Nernst effect and Seebeck effect under sufficient annealing demonstrate modified electrical transport properties resulting from induced disorder, including a change in carrier sign and an enhancement of the Nernst effect due to the CDW. Our results provide evidence of multiple phase transitions, which confirms the influence of CDW on the thermal properties of FeGe and demonstrates the suppression of CDW with sufficient disordering.
Strongly Correlated Electrons (cond-mat.str-el)
4 figures
Lattice vacancy migration barriers in Fe-Ni alloys, and why Ni atoms diffuse slowly: An ab initio study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Adam M. Fisher, Christopher D. Woodgate, Xiaoyu Zhang, George C. Hadjipanayis, Laura H. Lewis, Julie B. Staunton
The mobility of both Fe and Ni atoms in ferromagnetic $ \textrm{Fe}x \textrm{Ni}{1-x}$ alloys ($ 0.4 \leq x \leq 0.6$ ) is investigated within the framework of ab initio electronic structure calculations, using the nudged elastic band (NEB) method to accurately quantify energetic barriers to lattice vacancy migration. Both the atomically disordered ($ A1$ ) fcc phase, as well as the atomically ordered, tetragonal $ \textrm{L}1_0$ phase - which is under consideration as a material for a rare-earth-free ‘gap’ magnet for advanced engineering applications - are investigated. Across an ensemble of NEB calculations performed on supercell configurations spanning a range of compositions and containing disordered, partially ordered, and fully ordered structures, we find that Ni atoms are consistently significantly less mobile than Fe atoms. Crucially, we are able to interpret these findings in terms of the ferromagnetic alloy’s underlying spin-polarised electronic structure. Specifically, we report a coupling between the size of local lattice distortions and the magnitude of the local electronic spin polarisation around vacancies. This causes Fe atoms to relax into lattice vacancies, while Ni atoms remain rigidly fixed to their original lattice positions. This effect plays a key role in determining the reduced mobility of Ni atoms compared to that of Fe atoms. These results shed atomic-scale insight into the longstanding experimental observation that Ni exhibits remarkably slow atomic diffusion in Fe-Ni alloys.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Computational Physics (physics.comp-ph)
12 pages, 8 figures, 2 tables
Interferences Measure Topology
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Yuval Abulafia, Eric Akkermans
Topological materials are characterized by integer invariants that underpin their robust quantized electronic features, as famously exemplified by the Chern number in the integer quantum Hall effect. Yet, in most candidate systems, the observable linked to the topological invariant is unknown, preventing direct verification of their topological nature. Here we present a general method to identify topological materials by analyzing the local electronic density, $ \delta \rho(\boldsymbol{r})$ , and connecting it to Atiyah Singer index theorems. This approach enables a direct measurement of the winding number, the topological invariant of Hamiltonians with chiral symmetry, through a contour independent dislocation pattern of $ \delta \rho(\boldsymbol{r})$ created by interference from topological defects. Our method thus provides a direct route to detect and characterize quantum topological states, paving the way for their use as robust and entangleable building blocks in quantum technologies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 7 figures
Alloyed cementite (Fe-Ni-Cr)3C: structure and hyperfine field from DFT calculations and experimental comparison
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
The alloying elements introduced into carbon steel to enhance its mechanical properties also diffuse into cementite (Fe3C) particles, modifying their characteristics and thereby influencing the overall performance of the steel. This study employs density functional theory (DFT) calculations to investigate cementite doped with Ni and Cr which exhibit contrasting effects. The preferred lattice sites of impurity atoms were determined through a comparison of calculated and experimental structural parameters. The formation mechanism of the hyperfine magnetic field (HFF) and its correlation with atomic magnetic moments were systematically investigated. The validity of common approximations in Mössbauer spectroscopy analysis was evaluated for the cementite system. HFF distribution functions were modeled using calculated values and compared with experiments.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
19 pages, 12 figures. Submitted to Physics and Chemistry of Minerals
Measuring high field gradients of cobalt nanomagnets in a spin-mechanical setup
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Felix Hahne, Teresa Klara Pfau, Liza Žaper, Lucio Stefan, Thibault Capelle, Andrea Ranfagni, Martino Poggio, Albert Schliesser
Hybrid systems composed of a single nitrogen-vacancy center spin magnetically coupled to a macroscopic mechanical resonator constitute promising platforms for the realization of quantum information protocols and for quantum sensing applications. The magnetic structure that mediates the interaction must ensure high field gradients while preserving the spin and mechanical properties. We present a spin-mechanical setup built around a cobalt nanomagnet grown with focused electron beam-induced deposition. The magnetic structure is fully characterized, and a maximum gradient of $ 170,\mathrm{kT/m}$ is directly measured at a spin-oscillator distance of a few hundred nanometers. Spin coherence was preserved at the value of $ 20,\mathrm{ \mu s}$ up to a gradient of $ 25,\mathrm{kT/m}$ . The effect of the mechanical motion onto the spin dynamics was observed, thus signifying the presence of spin-mechanics coupling. Given the noninvasive nature of the nanomagnet deposition process, we foresee the adoption of such structures in hybrid platforms with high-quality factor resonators, in the “magnet on oscillator” configuration.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
The charge-carrier trapping effect on 1/f noise in monolayer graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
The frequency exponent of 1/f noise in graphene-boron nitride heterostructures is known to have multiple extrema in its dependence on the charge carrier concentration. This behavior is explained in the present paper as a result of the charge carrier trapping by impurities in the boron nitride. A kinetic equation for the charge carriers subject to trapping and interacting with acoustic phonons is derived. This equation is solved numerically, and the equilibrium solutions are used to evaluate the frequency exponent according to the quantum theory of 1/f noise. It is found that the frequency exponent does develop several minima and maxima, provided that the trapping probability is sufficiently wide and has a threshold with respect to the charge carrier energy. A detailed comparison with the experimental data is made, and the results are used to estimate the energy threshold and the trapping cross-section.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech)
22 pages, 6 figures
MC3D: The Materials Cloud computational database of experimentally known stoichiometric inorganics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-27 20:00 EDT
Sebastiaan P. Huber, Michail Minotakis, Marnik Bercx, Timo Reents, Kristjan Eimre, Nataliya Paulish, Nicolas Hörmann, Martin Uhrin, Nicola Marzari, Giovanni Pizzi
DFT is a widely used method to compute properties of materials, which are often collected in databases and serve as valuable starting points for further studies. In this article, we present the Materials Cloud Three-Dimensional Structure Database (MC3D), an online database of computed three-dimensional (3D) inorganic crystal structures. Close to a million experimentally reported structures were imported from the COD, ICSD and MPDS databases; these were parsed and filtered to yield a collection of 72589 unique and stoichiometric structures, of which 95% are, to date, classified as experimentally known. The geometries of structures with up to 64 atoms were then optimized using density-functional theory (DFT) with automated workflows and curated input protocols. The procedure was repeated for different functionals (and computational protocols), with the latest version (MC3D PBEsol-v2) comprising 32013 unique structures. All versions of the MC3D are made available on the Materials Cloud portal, which provides a graphical interface to explore and download the data. The database includes the full provenance graph of all the calculations driven by the automated workflows, thus establishing full reproducibility of the results and more-than-FAIR procedures.
Materials Science (cond-mat.mtrl-sci)
18 pages, 10 figures
Phase Coherent Transport in Two-Dimensional Tellurium Flakes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-27 20:00 EDT
Mohammad Hafijur Rahaman, Nathan Sawyers, Mourad Benamara, Trudie Culverhouse, Repaka Maheswar, Qiyuan He, Hugh Churchill, Dharmraj Kotekar Patil
Elemental tellurium (Te) is a compelling van der Waals material due to its interesting chiral crystal structure and predicted topological properties. Here, we report the fabrication and comprehensive quantum transport study of devices based on Te flakes with varying thicknesses. We demonstrate a hole mobility reaching up to 1000 cm2/V.s in a 17 nm thick flake at 30 Kelvin. At deep cryogenic temperatures (< 50mK), the transport characteristics transition from Coulomb blockade in the low carrier density regime to pronounced Fabry-Pérot (F-P) interference at higher densities. Notably, the visibility of these F-P oscillations is significantly enhanced in the thinner flake device. The application of a magnetic field reveals a clear Zeeman splitting of the conductance peaks. The rich variety of quantum transport phenomena observed underscores the high quality of our thin Te flakes and establishes them as a promising platform for exploring novel physics and device concepts, such as topological superconductivity and low-power spintronic applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft), Quantum Physics (quant-ph)
25 pages, 4 figures, Supplementary 6 figures
Disorder-induced proximate quantum spin ice phase in Pr$_2$Sn$_2$O$_7$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-27 20:00 EDT
Yi Luo, Joseph A. M. Paddison, Brenden R. Ortiz, Miles Knudtson, Stephen D. Wilson, Jue Liu, Benjamin A. Frandsen, Si Athena Chen, Matthias Frontzek, Andrey Podlesnyak, Adam A. Aczel
We report a comprehensive bulk characterization and neutron scattering investigation of single-crystalline Pr$ _2$ Sn$ 2$ O$ 7$ , a magnetic pyrochlore synthesized via a flux-growth method. Unpolarized neutron diffuse scattering reveals the emergence of spin-ice correlations below $ T \sim 1$ K, evidenced by the development of anisotropic pinch-point features that are consistent with quantum-spin-ice (QSI) behavior. A.C. susceptibility measurements indicate a progressive slowing of spin dynamics in this regime, culminating in complete spin freezing below $ T_f \approx 0.15$ K. Inelastic neutron scattering at $ T = 0.5$ K reveals a broad spectrum of quasi-elastic magnetic excitations, with intensity in the low-energy range $ [0, 0.2]$ meV significantly suppressed below $ T_f$ . Meanwhile, an incipient (100)-type magnetic order begins to nucleate, and a gapped excitation centered at $ \hbar\omega = 0.23$ meV persists. We further identify two distinct dynamical timescales above $ T_f$ , a slow component $ \tau{\mathrm{slow}} \sim 10^{-5}$ s and a fast component $ \tau{\mathrm{fast}} \sim 10^{-10}$ s, in quantitative agreement with theoretical predictions for QSI systems. Taken together, these results indicate that Pr$ _2$ Sn$ _2$ O$ _7$ enters a disorder-induced spin-frozen phase below $ T_f$ , lying in close proximity to a $ U(1)$ quantum spin liquid.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
20 pages, 17 figures, 2 tables