CMP Journal 2025-08-04
Statistics
Nature: 2
Nature Materials: 1
Nature Nanotechnology: 2
Nature Physics: 1
arXiv: 47
Nature
Real-time in-situ magnetization reprogramming for soft robotics
Original Paper | Biomedical engineering | 2025-08-03 20:00 EDT
Xianqiang Bao, Fan Wang, Jianhua Zhang, Mingtong Li, Shuaizhong Zhang, Ziyu Ren, Jiahe Liao, Yingbo Yan, Wenbin Kang, Rongjing Zhang, Zemin Liu, Tianlu Wang, Metin Sitti
Magnetic soft robots offer considerable potential across various scenarios, such as biomedical applications and industrial tasks, due to their shape programmability and reconfigurability, safe interaction, and biocompatibility1-4. Despite recent advances, magnetic soft robots are still limited by the difficulties in reprogramming their required magnetization profiles in real time on the spot (in situ), which is essential for performing multiple functions or executing diverse tasks5,6. Here, we introduce a method for real-time, in situ magnetization reprogramming that enables the rearrangement and recombination of magnetic units to achieve diverse magnetization profiles. We explore the applications of this method in structures of varying dimensions, from one-dimensional (1D) tubes to three-dimensional (3D) frameworks, showcasing a diverse and expanded range of configurations and their deformations. This method also demonstrates versatility in diverse scenarios, including navigating around objects without undesired contact, reprogramming cilia arrays, managing multiple instruments cooperatively or independently under the same magnetic field, and manipulating objects of various shapes. These capabilities extend the range of applications for magnetic actuation technologies. Furthermore, this method emancipates magnetic soft robots from the sole reliance on external magnetic fields for shape change, facilitating unprecedented modes and varieties of deformation while simultaneously reducing the need for complex magnetic field generation systems; thereby, opening new avenues for the development of magnetic actuation technologies.
Biomedical engineering, Mechanical engineering
Direct identification of Ac and No molecules with an atom-at-a-time technique
Original Paper | Nuclear chemistry | 2025-08-03 20:00 EDT
Jennifer L. Pore, Jacklyn M. Gates, David A. Dixon, Fatima H. Garcia, John K. Gibson, John A. Gooding, Mallory McCarthy, Rodney Orford, Ziad Shafi, David K. Shuh, Sarah Sprouse
The periodic table provides an intuitive framework for understanding chemical properties. However, its traditional patterns may break down for the heaviest elements occupying the bottom of the chart. The large nuclei of actinides (Z > 88) and superheavy elements (Z ≥ 104) give rise to relativistic effects that are expected to substantially alter their chemical behaviours, potentially indicating that we have reached the end of a predictive periodic table1. Relativistic effects have already been cited for the unusual chemistry of the actinides compared with those of their lanthanide counterparts2. Unfortunately, it is difficult to understand the full impact of relativistic effects, as research on the later actinides and superheavy elements is scarce. Beyond fermium (Z = 100), elements need to be produced and studied one atom at a time, using accelerated ion beams and state-of-the-art experimental approaches. So far, no experiments have been capable of directly identifying produced molecular species. Here ions of actinium (Ac, Z = 89) and nobelium (No, Z = 102) were synthesized through nuclear reactions at the 88-Inch Cyclotron facility at Lawrence Berkeley National Laboratory and then exposed to trace amounts of H2O and N2. The produced molecular species were directly identified by measuring their mass-to-charge ratios using FIONA (For the Identification Of Nuclide A)3. These results mark the first, to our knowledge, direct identification of heavy-element molecular species using an atom-at-a-time technique and highlight the importance of such identifications in future superheavy-element chemistry experiments to deepen understanding of their chemical properties.
Nuclear chemistry, Nuclear physics
Nature Materials
Fatigue in metals and alloys
Review Paper | Engineering | 2025-08-03 20:00 EDT
Qingsong Pan, Lei Lu
Fatigue failure in metals remains a concern across engineering disciplines, substantially influencing the design, reliability and economic viability of essential load-bearing structure components. Despite notable advances in materials science, fatigue-induced failures–particularly in extreme applications such as deep-space exploration–continue to pose challenges owing to their inherent complex and unpredictable nature. This Perspective provides a concise overview of emerging frontiers in improving fatigue resistance, along with key advancements in our understanding of metal fatigue. It also explores current opportunities and challenges, ranging from the development of promising fatigue-resistant materials through spatially heterogeneous composition and microstructure design to innovations in testing methods, characterization techniques, theoretical frameworks and modelling methodologies for metal fatigue.
Engineering, Materials science
Nature Nanotechnology
Real-time observation of topological defect dynamics mediating two-dimensional skyrmion lattice melting
Original Paper | Phase transitions and critical phenomena | 2025-08-03 20:00 EDT
Raphael Gruber, Jan Rothörl, Simon M. Fröhlich, Maarten A. Brems, Fabian Kammerbauer, Maria-Andromachi Syskaki, Elizabeth M. Jefremovas, Sachin Krishnia, Asle Sudbø, Peter Virnau, Mathias Kläui
Topological defects are the key feature mediating two-dimensional phase transitions. However, both resolution and tunability have been lacking to access the dynamics of these transitions in the various two-dimensional systems explored. Skyrmions in magnetic thin films are two-dimensional, topologically non-trivial quasi-particles that provide rich dynamics as well as tunability as an essential ingredient for the control of their phase behaviour. With dynamic Kerr microscopy, we directly capture the melting of a confined two-dimensional magnetic skyrmion lattice in a Ta/CoFeB/Ta/MgO/Ta magnetic multilayer system with high resolution in real time and real space. By the applied magnetic field, we tune the skyrmion size and effective temperature on the fly to drive the two-step melting through an intermediate hexatic regime between the solid lattice and the isotropic liquid. We quantify the characteristic occurrence of topological defects mediating the transitions and reveal the dynamics of the lattice dislocations. The full real-time and real-space imaging reveals the diffusion coefficient of dislocations, which is two orders of magnitude higher than that of skyrmions.
Phase transitions and critical phenomena, Spintronics
A versatile antibody capture system drives specific in vivo delivery of mRNA-loaded lipid nanoparticles
Original Paper | Drug delivery | 2025-08-03 20:00 EDT
Moore Z. Chen, Daniel Yuen, Victoria M. McLeod, Ken W. Yong, Cameron H. Smyth, Bruna Rossi Herling, Thomas. J. Payne, Stewart A. Fabb, Matthew J. Belousoff, Azizah Algarni, Patrick M. Sexton, Christopher J. H. Porter, Colin W. Pouton, Angus P. R. Johnston
Efficient and precise delivery of mRNA is critical to advance mRNA therapies beyond their current use as vaccines. Lipid nanoparticles (LNPs) efficiently encapsulate and protect mRNA, but non-specific cellular uptake may lead to off-target delivery and minimal delivery to target cells. Functionalizing LNPs with antibodies enables targeted mRNA delivery, but traditional modification techniques require complex conjugation and purification, which often reduces antibody affinity. Here we present a simple method for capturing antibodies in their optimal orientation on LNPs, without antibody modification or complex purification. This strategy uses an optimally oriented anti-Fc nanobody on the LNP surface to capture antibodies, resulting in protein expression levels more than 1,000 times higher than non-targeted LNPs and more than 8 times higher than conventional antibody functionalization techniques. These precisely targeted LNPs showed highly efficient in vivo targeting to T cells, with minimal delivery to other immune cells. This approach enables the rapid development of targeted LNPs and has the potential to broaden the use of mRNA therapies.
Drug delivery, Nanoparticles
Nature Physics
Control of collective activity to crystallize an oscillator gas
Original Paper | Phase transitions and critical phenomena | 2025-08-03 20:00 EDT
Marine Le Blay, Joshua H. K. Saldi, Alexandre Morin
Motility-induced phase separation occurs in assemblies of self-propelled units when activity is coupled negatively to density. By contrast, the consequences of a positive coupling between density and activity on the collective behaviour of active matter remain unexplored. Here we show that collective activity can emerge from such a positive coupling among non-motile building blocks. We perform experiments with self-sustained oscillators powered by contact-charge electrophoresis. Although the oscillators are non-motile by design, they spontaneously form an active gas when confined together. The super-elastic nature of collisions constitutes a positive density-activity coupling and underlies the active gas properties. Elucidating the origin of binary collisions allows us to precisely control the structure of the active gas and its eventual crystallization. Beyond considering the overlooked positive coupling between density and activity, our work suggests that rich collective properties can emerge not only from the symmetry of interactions between active building blocks but also from their adaptable and responsive behaviour.
Phase transitions and critical phenomena, Statistical physics
arXiv
Anyon superfluid in trilayer quantum Hall systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-04 20:00 EDT
Intertwining intrinsic topological order with gapless collective modes remains a central challenge in many-body physics. We show that a quantum-Hall trilayer at $ \nu_{1}=\nu_{2}=\nu_{3}= \frac13$ , tuned solely by the inter-layer spacing $ d$ , realizes this goal. Large-scale density-matrix renormalization group (DMRG) calculations and a Chern-Simons field theory analysis reveal an intermediate ``anyon-exciton condensate’’ separating the familiar $ \nu_{\mathrm{tot}}=1$ exciton condensate ($ d \to 0$ ) from three decoupled Laughlin liquids ($ d \to \infty$ ). In this phase, neutral bi-excitons condense while a $ \nu=\frac23$ Laughlin topological order survives, yielding a Goldstone mode coexisting with fractionalized anyons. A Ginzburg-Landau analysis maps out the finite-temperature phase diagram. The anyon-exciton condensate can be experimentally verified through a vanishing double-counter-flow resistance and a fractional layer-resolved Hall resistivity $ R_{xy}=\frac{5}{2} h/e^{2}$ , both within reach of existing high-mobility trilayer devices.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 1 figure
Double descent: When do neural quantum states generalize?
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-08-04 20:00 EDT
M. Schuyler Moss, Alev Orfi, Christopher Roth, Anirvan M. Sengupta, Antoine Georges, Dries Sels, Anna Dawid, Agnes Valenti
Neural quantum states (NQS) provide flexible wavefunction parameterizations for numerical studies of quantum many-body physics. While inspired by deep learning, it remains unclear to what extent NQS share characteristics with neural networks used for standard machine learning tasks. We demonstrate that NQS exhibit the double descent phenomenon, a key feature of modern deep learning, where generalization worsens as network size increases before improving again in an overparameterized regime. Notably, we find the second descent to occur only for network sizes much larger than the Hilbert space dimension, indicating that NQS typically operate in an underparameterized regime, where increasing network size can degrade generalization. Our analysis reveals that the optimal network size in this regime depends on the number of unique training samples, highlighting the importance of sampling strategies. These findings suggest the need for symmetry-aware, physics-informed architecture design, rather than directly adopting machine learning heuristics.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Physics (quant-ph)
17 pages, 14 figures
Fragmented eigenstate thermalization versus robust integrability in long-range models
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-04 20:00 EDT
Soumya Kanti Pal, Lea F Santos
Understanding the stability of integrability in many-body quantum systems is key to controlling their dynamics and predicting thermalization. While much is known about how integrability breaks down in short-range interacting systems, the corresponding picture for long-range couplings remains incomplete. Yet long-range interactions are both ubiquitous in nature and readily engineered in modern experimental platforms. Here, we show that integrability in fully connected models is either robust or extremely fragile depending on whether the perturbation is non-extensive, extensive one-body, or extensive two-body. In a finite system with short-range interactions, any of these perturbations can induce chaos when applied with finite strength. In contrast, in fully connected finite models, chaos is induced by extensive two-body perturbations, and they do so even at infinitesimal strength. In this case, chaos emerges within quasi-symmetry sectors, leading to a fragmented manifestation of the eigenstate thermalization hypothesis (ETH). This challenges previous claims of ETH violation in quantum systems with strong long-range interactions.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
6+5 pages, Comments are welcome
Contactless indentation of a soft boundary by a rigid particle in shear flow
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-04 20:00 EDT
The dynamics of a rigid particle above a fluid-fluid interface in shear flow is studied here numerically and analytically as a function of the downward force applied on the particle. It is found here that the particle goes below the equilibrium level of the interface for a strong enough downward force. Such states remain stable under flow, with a fluid film of a well-defined thickness separating the particle from the indented interface. This result contradicts the classical lubrication theory, which predicts an infinitely large downward force being necessary for the particle to approach the equilibrium level of the interface. It is found that the classical lubrication approximation is only valid in a narrow range of shear rates, which shrinks to a point when the particle approaches the equilibrium level of the interface. The gap renormalization model, proposed here, cures this limitation of the classical lubrication theory, showing quantitative agreement with the numerical results when the particle touches the equilibrium level of the interface. It is found that the gap renormalization model provides a quantitative interpretation of the recent experimental results, including the range of particle heights above the interface for which the classical lubrication approximation breaks down.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
Switchable Exchange Bias Resulting from Correlated Domain Structures in Orthogonally Coupled Antiferromagnet/Ferromagnet van der Waals Heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-04 20:00 EDT
Aditya Kumar, Sadeed Hameed, Thibaud Denneulin, Aravind Puthirath Balan, Joseph Vas, Kilian Leutner, Lei Gao, Olena Gomonay, Jairo Sinova, Rafal E. Dunin-Borkowski, Mathias Kläui
Van der Waals (vdW) magnetic heterostructures offer a versatile platform for engineering interfacial spin interactions with atomic precision, enabling nontrivial spin textures and dynamic behaviors. In this work, we report robust asymmetric magnetization reversal and exchange bias in Fe3GeTe2 (FGT), driven by interlayer exchange coupling with the A-type antiferromagnet CrSBr. Despite the orthogonal magnetic anisotropies out-of-plane easy axis in FGT and in-plane in CrSBr, we observe a strong interfacial exchange interaction that gives rise to pronounced and switchable exchange bias and asymmetric switching in FGT, persisting up to the Néel temperature of CrSBr (132 K) as revealed by anomalous Hall effect measurements.
We uncover the microscopic origin of this behavior through cross-sectional magnetic imaging of the domain structure using off-axis electron holography. The results reveal that the asymmetric switching and exchange bias arise from the influence of CrSBr on the domain configuration of FGT, where the in-plane antiferromagnetic state of CrSBr promotes the formation of stripe-like domain structures in FGT with circular rotation of magnetization in the cross-sectional bc plane defined by the easy axes of both FGT and CrSBr. These findings elucidate the mechanism of exchange bias in orthogonally coupled van der Waals systems and demonstrate a pathway for stabilizing three-dimensional domain structures in ferromagnets through interfacial exchange interactions.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Dynamical mean field theory with quantum computing
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-04 20:00 EDT
Near-term quantum processors are limited in terms of the number of qubits and gates they can afford. They nevertheless give unprecedented access to programmable quantum systems that can efficiently, although imperfectly, simulate quantum time evolutions. Dynamical mean field theory, on the other hand, maps strongly-correlated lattice models like the Hubbard model onto simpler, yet still many-body models called impurity models. Its computational bottleneck boils down to investigating the dynamics of the impurity upon addition or removal of one particle. This task is notoriously difficult for classical algorithms, which has warranted the development of specific classical algorithms called “impurity solvers” that work well in some regimes, but still struggle to reach some parameter regimes. In these lecture notes, we introduce the tools and methods of quantum computing that could be used to overcome the limitations of these classical impurity solvers, either in the long term – with fully quantum algorithms, or in the short term – with hybrid quantum-classical algorithms.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
Lecture notes for the 2025 Autumn School on Correlated Electrons. Comments welcome
Autumn School on Correlated Electrons: Understanding Correlated Materials with DMFT, Vol. 15, edited by E. Pavarini and E. Koch (Forschungszentrum Juelich, 2025)
Impact of Metal Cation on Chiral Properties of 2D Halide Perovskites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-04 20:00 EDT
Mike Pols, Helena Boom, Geert Brocks, Sofía Calero, Shuxia Tao
Chiral two-dimensional (2D) halide perovskites are formed by embedding chiral organic cations in a perovskite crystal structure. The chirality arises from distortions of the 2D metal halide layers induced by the packing of these organic cations. Sn-based octahedra spontaneously distort, but it remains unclear whether this intrinsic structural instability enhances the chirality. We investigate the effect of the metal cation on structural and phonon chirality in MBA$ _{2}$ Sn$ _{\mathrm{x}}$ Pb$ _{1-\mathrm{x}}$ I$ _{4}$ (x = 0, 1/2, and 1). Incorporating Sn does distort the metal halide octehedra, yet it only has a minor impact on the structural chirality. In contrast, the phonons in MBA$ _{2}$ SnI$ _{4}$ are substantially more chiral than in MBA$ _{2}$ PbI$ _{4}$ , especially the in-plane acoustic modes. However, this enhanced phonon chirality does not lead to a generation of a larger angular momentum under a temperature gradient, because the contributions of different chiral phonons tend to compensate one another.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
8 pages, 6 figures
Atomistic Simulations Reveal the Need to Reassess Standard Thermodynamic Models of Coherent Precipitates
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-04 20:00 EDT
Accurate models of precipitation kinetics are essential to control and design structural materials. These models are highly sensitive to the thermodynamic description of precipitates. We use atomistic simulations of a model Fe-Cr system to assess two commonly used assumptions in the thermodynamic modeling of coherent precipitates: that elastic effects can be neglected for systems with a small lattice misfit and that size effects can be neglected for low levels of supersaturation. We find that these assumptions cannot be maintained for an accurate description of interfacial equilibrium, even when lattice misfits are below 1 % and supersaturation values are below 1 %. Additionally, we find a surprising trend at large precipitate radii that suggests the importance of higher-order effects that are commonly neglected. The results and insights from this study highlight the need to revisit current approaches in modeling solid-state precipitation.
Materials Science (cond-mat.mtrl-sci)
Nambu Non-equilibrium Thermodynamics I: Foundation
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-04 20:00 EDT
So Katagiri, Yoshiki Matsuoka, Akio Sugamoto
We propose a novel framework of non-equilibrium thermodynamics, termed Nambu Non-equilibrium Thermodynamics (NNET), which integrates reversible dynamics governed by the Nambu bracket with irreversible dynamics driven by entropy gradients. This framework is developed axiomatically and enables the description of far-from-equilibrium systems in which entropy can transiently decrease – a regime difficult to handle within conventional approaches such as Onsager’s linear response theory, Prigogine’s General Evolution Criterion (GEC), or the GENERIC framework.
As an illustrative example, we analyze a triangular chemical reaction system. We demonstrate that, without assuming detailed balance or linearity, two geometric conserved quantities naturally emerge: one associated with cyclic symmetry in the reaction space, and another that vanishes under symmetric reaction rates. This highlights the extended descriptive power of NNET and its capacity to unify cyclic dynamics and dissipation within a covariant structure. The generalization to higher-order nonlinear systems and applications to oscillatory or spiking non-equilibrium behavior will be discussed in subsequent papers.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Mathematical Physics (math-ph)
10 pages
Explicit equivalence between the spectral localizer and local Chern and winding markers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-04 20:00 EDT
Lucien Jezequel, Jens H. Bardarson, Adolfo G. Grushin
Topological band insulators are classified using momentum-space topological invariants, such as Chern or winding numbers, when they feature translational symmetry. The lack of translation symmetry in disordered, quasicrystalline, or amorphous topological systems has motivated alternative, real-space definitions of topological invariants, including the local Chern marker and the spectral localizer invariant.
However, the equivalence between these invariants is so far implicit. Here, we explicitly demonstrate their equivalence from a systematic perturbative expansion in powers of the spectral localizer’s parameter $ \kappa$ . By leveraging only the Clifford algebra of the spectral localizer, we prove that Chern and winding markers emerge as leading-order terms in the expansion. It bypasses abstract topological machinery, offering a simple approach accessible to a broader physics audience.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn)
Atomic Interface Engineering of Battery Current Collectors via Ion Implantation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-04 20:00 EDT
Yue Li, Xuanguang Ren, Xueting Feng, Lingcheng Kong, Fengping Luo, Yang Xu, Liu Qian, Yusheng Ye, Ziqiang Zhao, Xin Gao, Jin Zhang
Atomic interface engineering (AIE) is critical for advancing technologies in energy storage, catalysis, and microelectronics. In anode-less lithium metal batteries (ALLMBs), AIE is essential for controlling interfacial chemistry governing lithium deposition and solid electrolyte interphase (SEI) formation on copper current collectors. However, native copper surfaces readily oxidize, forming electronically insulating oxides that degrade performance and obscure failure mechanisms. Here, we report a scalable ion implantation strategy to create an atomically clean and robust copper interface. By implanting copper ions into commercial foils, we simultaneously remove the native oxide and introduce subsurface vacancy clusters that act as oxygen traps, yielding an oxidation-resistant and conductive surface. Experimental characterization and multiscale simulations reveal that these engineered vacancies suppress reoxidation and guide the formation of an ultrathin Li2O-enriched solid electrolyte interphase. When applied in ALLMBs, the current collectors enable uniform lithium deposition, suppress parasitic reactions, and deliver a Coulombic efficiency of 99.0% over 400 cycles under lean electrolyte conditions. This work presents a generalizable and industry-compatible approach for stabilizing electrochemical interfaces.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
The Quadrupole Moment of Higher-Order Topological Insulator at Finite temperature
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-04 20:00 EDT
We study the higher-order topological insulators at finite temperature based on a generalized real-space quadrupole moment, which extends the ground state expectations to ensemble averages. Our study reveals that chiral symmetry alone dictates that the quadrupole moment must be quantized to two values of $ 0$ and $ 1/2$ , even at finite temperature. It is found that finite temperature can induce a topological phase transition from non-trivial to trivial. Furthermore, we found that the anisotropic intra-cell hopping can lead to a reentrant topological phase transition, in which the system becomes topological again with rising temperature. This reentrant behavior is in stark contrast to the results at zero temperature. We also investigate the effects of the quasi-disorder hopping on the topology. It is found that the initially trivial system can be driven into a topological phase with strong enough disorder strength, which closely resembles the topological Anderson transition. Our work provides an example for studying the finite temperature topology of higher-order topological insulators.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 6 figures
High-fidelity electronic structure and properties of InSb: $G_0W_0$ and Bayesian-optimized hybrid functionals and DFT+$U$ approaches
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-04 20:00 EDT
Ritwik Das, Anne-Sophie Grimault-Jacquin, Frédéric Aniel
This study presents a refined approach to computing the electronic structure of indium antimonide (InSb) using advanced \textit{ab initio} techniques with the In and Sb $ 4d^{10}$ semicore electrons included in the valence states. These states are modeled using fully relativistic projector augmented waves (PAW) and optimized norm-conserving Vanderbilt (ONCV) pseudopotentials. However, standard Kohn-Sham density-functional theory (DFT) calculations with these pseudopotentials often produce non-physical band inversions and incorrect band gaps at the $ \Gamma$ -point due to $ 5p$ -$ 4d$ repulsion and self-interaction errors (SIE). To resolve these issues, we apply a combination of hybrid Heyd-Scuseria-Ernzerhof (HSE) exchange-correlation (XC) functionals, many-body perturbation theory (MBPT) via quasiparticle $ G_0W_0$ , and DFT+$ U$ , significantly improving the accuracy of the band structure over previous studies. A Bayesian optimization framework is used to refine key parameters, including the inverse screening length ($ \mu$ ) and Hartree-Fock (HF) exchange fraction ($ \alpha$ ) in HSE-based XC functionals, as well as the Hubbard $ U$ parameters in DFT+$ U$ , leading to significantly improved band structure predictions. This approach yields highly precise band gaps, bulk moduli, effective masses, Luttinger parameters, valence bandwidth, and $ 4d$ band positions, achieving unprecedented agreement with experimental data. The resulting model resolves the long-standing incomplete description of InSb’s electronic band structure and provides a transferable computational framework for accurate electronic structure predictions across diverse material systems, offering valuable insights for future electronic, optoelectronic, energy, and quantum applications.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Accepted in Physical Review B (APS). 16 pages, 3 figures. Supplemental Material included in the source folder
High harmonic generation reflecting the sub-cycle evolution of the Mott transition under a mid-infrared electric field
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-04 20:00 EDT
Ryohei Ikeda, Yuta Murakami, Daiki Sakai, Tatsuya Miyamoto, Toshimitsu Ito, Hiroshi Okamoto
Solids in an intense laser field show high-harmonic generation (HHG), which can provide information on carrier dynamics and band structures in weakly correlated systems. In strongly correlated systems, a laser field can induce a transition between the various electronic phases formed by the entanglement of charge, spin, and orbital degrees of freedom via carrier generation. The HHG accompanying this process should contain information on the nonequilibrium electronic-state dynamics along the oscillating field - an aspect that remains unresolved to date. Here, we show that an intense mid-infrared (MIR) pulse induces a Mott insulator-metal transition in a one-dimensional cuprate, Sr2CuO3, the evolution of which is reflected by the spectral features of HHs. When the electric-field amplitude exceeds 6 MV/cm, carriers are efficiently generated and each harmonic frequency decreases from odd multiples of the MIR frequency. Dynamical mean-field theory indicates that these redshifts originate from a series of electronic-structure reconstructions in each electric-field cycle during the melting of the Mott-insulator state, which modifies the radiation phase from carrier recombination cycle-by-cycle. This phenomenon is negligible in rigid-band systems. This experimental-theoretical study confirms that HH spectroscopy research can potentially unravel the sub-cycle dynamics of nonequilibrium phase transitions in correlated materials.
Strongly Correlated Electrons (cond-mat.str-el), Optics (physics.optics)
Large phonon-drag thermopower polarity reversal in Ba-doped KTaO3
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-04 20:00 EDT
Mohamed Nawwar, Samuel Poage, Tobias Schwaigert, Maria N. Gastiasoro, Salva Salmani-Rezaie, Darrell G. Schlom, Kaveh Ahadi, Brandi L. Wooten, Joseph P. Heremans
This study reports the observation of phonon-drag thermopower polarity reversal in Ba-doped KTaO3 thin films, mediated by electron-phonon Umklapp scattering. Epitaxial films with distinct carrier concentrations (3.7 x 10^20 cm^-3 and 4.9 x 10^19 cm^-3) were grown via molecular-beam epitaxy. In heavily doped samples, where the Fermi surface spans 80% of the Brillouin zone, the Umklapp condition is satisfied, reversing electron momentum. This manifests as a sign-reversal in the thermopower around 80 K upon cooling despite the sample having only n-type carriers. On the other hand, the lightly doped sample (4.9 x 10^19 cm^-3) exhibits only a negative thermopower down to 2 K. These results advance the understanding of Umklapp electron-phonon drag in oxides and highlight KTaO3’s potential for engineering unconventional thermoelectric materials.
Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con)
Scale dependence of segregation patterns in the filling of silos
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-04 20:00 EDT
Shivakumar Athani, Benjy Marks, François Guillard, Alistair Gillespie, Itai Einav
Size segregation in granular flows is a well-known phenomenon: laboratory experiments consistently show that large particles migrate toward silo walls during filling, while smaller particles concentrate near the center. Paradoxically, field observations in large-scale industrial silos often report the opposite pattern, challenging these findings. We demarcate these patterns through a systematic experimental study spanning a range of dimensionless numbers relevant to bidisperse granular flows in quasi-2D silos under both dry and immersed conditions, varying container geometry and fluid viscosity. Image analysis reveals that the observed patterns are governed by two key dimensionless parameters: the slenderness of the silo and the Stokes number, which encapsulates the balance between particle inertia and viscous drag. Our results demonstrate the role of fluids on segregation dynamics and provide a unified scaling framework that reconciles laboratory- and field-scale observations in air.
Soft Condensed Matter (cond-mat.soft)
Etching-to-deposition transition in SiO$_2$/Si$_3$N$_4$ using CH$_x$F$_y$ ion-based plasma etching: An atomistic study with neural network potentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-04 20:00 EDT
Hyungmin An, Sangmin Oh, Dongheon Lee, Jae-hyeon Ko, Dongyean Oh, Changho Hong, Seungwu Han
Plasma etching, a critical process in semiconductor fabrication, utilizes hydrofluorocarbons both as etchants and as precursors for carbon film formation, where precise control over film growth is essential for achieving high SiO$ _2$ /Si$ _3$ N$ _4$ selectivity and enabling atomic layer etching. In this work, we develop neural network potentials (NNPs) to gain atomistic insights into the surface evolution of SiO$ _2$ and Si$ _3$ N$ _4$ under hydrofluorocarbon ion bombardment. To efficiently sample diverse local configurations without exhaustive enumeration of ion-substrate combinations, we propose a vapor-to-surface sampling approach using high-temperature, low-density molecular dynamics simulations, supplemented with baseline reference structures. The NNPs, refined through iterative training, yield etching characteristics in MD simulations that show good agreement with experimental results. Further analysis reveals distinct mechanisms of carbon layer formation in SiO$ _2$ and Si$ _3$ N$ _4$ , driven by the higher volatility of carbon-oxygen byproducts in SiO$ _2$ and the suppressed formation of volatile carbon-nitrogen species in Si$ _3$ N$ _4$ . This computational framework enables quantitative predictions of atomistic surface modifications under plasma exposure and provides a foundation for integration with multiscale process modeling, offering insights into semiconductor fabrication processes.
Materials Science (cond-mat.mtrl-sci)
Uniform electronic states and $s$-wave superconductivity in a strongly disordered high-entropy compound (RuRhPdIr)${0.6}$Pt${0.4}$Sb
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-04 20:00 EDT
Yufu Yamada, Shunsaku Kitagawa, Taishi Ihara, Kenji Ishida, Naoto Uematsu, Daigorou Hirai, Koshi Takenaka
High-entropy compounds, where multiple elements occupy a single crystallographic site in a highly disordered manner, challenge conventional understandings of electronic structure based on periodicity and well-defined band dispersion. Here, we report a detailed nuclear magnetic resonance study of the high-entropy superconductor (RuRhPdIr)$ _{0.6}$ Pt$ _{0.4}$ Sb, revealing a spatially homogeneous electronic environment in the normal state, in stark contrast to its crystallographically disordered lattice. The superconducting state exhibits a small but solid Hebel-Slichter coherence peak followed by a significant decrease in the nuclear spin-lattice relaxation rate, providing compelling evidence for fully gapped $ s$ -wave pairing. Our findings not only deepen the understanding of superconductivity in highly disordered quantum materials but also open a new pathway for exploring novel superconducting states in entropy-stabilized systems.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
5 pages, 5 figures
Phys. Rev. B 112, L020508 (2025)
Multivalent linkers mediated ultra-sensitive bio-detection
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-04 20:00 EDT
Xiuyang Xia, Yuhan Peng, Ran Ni
In biosensing and diagnostic applications, a key objective is to design detection systems capable of identifying targets at very low concentrations, i.e., achieving high sensitivity. Here, we propose a linker-mediated detection scheme in which the presence of target molecules (linkers) facilitates the adsorption of ligand-coated guest nanoparticles onto a receptor-coated host substrate. Through a combination of computer simulations and mean-field theory, we demonstrate that, at fixed overall binding strength, increasing the valency of linkers exponentially lowers the concentration threshold for detection. This enables the identification of targets at extremely low concentrations, which is critical for early-stage disease and pathogen diagnostics. Furthermore, superselectivity with respect to binding strength is preserved for multivalent linkers, allowing for effective discrimination between targets and non-targets. Our findings highlight multivalency engineering of linkers as a powerful strategy to dramatically enhance the sensitivity of biodetection systems.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph)
Self-strain suppression of the metal-to-insulator transition in phase-change oxide devices
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-04 20:00 EDT
Nicolò D’Anna, Nareg Ghazikhanian, Erik S. Lamb, Edoardo Zatterin, Mingze Wan, Ashley Thorshov, Ivan K. Schuller, Oleg Shpyrko
Quantum materials exhibiting phase transitions which can be controlled through external stimuli, such as electric fields, are promising for future computing technologies beyond conventional semiconductor transistors. Devices that take advantage of structural phase transitions have inherent built-in memory, reminiscent of synapses and neurons, and are thus natural candidates for neuromorphic computing. Of particular interest are phase-change oxides, which allow for control over the metal-to-insulator transition. Here, we report X-ray nano-diffraction structural imaging of micro-devices fabricated with the archetypal phase-change material vanadium sesquioxide (V$ _2$ O$ _3$ ). The devices contain a Ga ion-irradiated region where the metal-to-insulator transition critical temperature is lowered, a useful feature for controlling neuron-like spiking behavior. Results show that strain, induced by crystal lattice mismatch between the pristine and irradiated material, leads to a suppression of the metal-to-insulator-transition. Suppression occurs within the irradiated region or along its edges, depending on the defect-distribution and the size of the region. The observed self-straining effect could extend to other phase-change oxides and dominate as device dimensions are reduced and become too small to dissipate strain within the irradiated region. The findings are important for phase engineering in phase-change devices and highlight the necessity to study phase transitions at the nanoscale.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
8 pages, 5 figures
Extrinsic nature of the polarization in hafnia ferroelectrics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-04 20:00 EDT
Binayak Mukherjee (1), Natalya S. Fedorova (1), Jorge Íñiguez-González (1 and 2) ((1) Luxembourg Institute of Science and Technology, (2) University of Luxembourg)
Hafnia and related fluorites defy our understanding of ferroelectricity, even if we restrict ourselves to the intrinsic properties of ideal crystals. Here we focus on a critical puzzle, namely, the sign of the electric polarization. Using first-principles simulations, we show that a polar hafnia layer with a fixed atomic configuration can give rise to depolarizing fields of either positive or negative sign, depending on the environment. This implies that (the sign of) the polarization in hafnia is extrinsic in nature. We explain this result and discuss its relevance to other ferroelectric families.
Materials Science (cond-mat.mtrl-sci)
7 pages, 5 figures
Observation and control of potential-dependent surface state formation at a semiconductor-electrolyte interface via the optical anisotropy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-04 20:00 EDT
Marco Flieg, Margot Guidat, Matthias M. May
The interface between semiconductors and ion-conducting electrolytes is characterised by charge distributions and potential drops that vary substantially with the evolution of surface states. These surface states at the very interface to the liquid can form or be passivated, depending on the applied potential between electrode and electrolyte, and hereby fundamentally impact properties such as charge transfer. Characterisation and understanding of such potential-dependent surface states with high spatial and temporal resolution is a significant challenge for the understanding and control of semiconductor-electrolyte interfaces. Here, we show that the optical anisotropy of InP(100) can be used to detect the potential-dependent formation of highly ordered surface states under operating conditions. Upon formation of a surface state in the bandgap of the semiconductor, the potential drop and hence the electric field is shifted away from the semiconductor to the Helmholtz-layer of the electrolyte. This modifies the instantaneous response of the optical anisotropy to disturbances of the applied potential. We propose an electrochemical variant of the linear electro-optical effect and our findings open a novel route for understanding these interfaces. The results show how surface states from surface reconstructions at this reactive interface can be switched on or off with the applied potential.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
6 pages, 3 figures
The effect of dephasing and spin-lattice relaxation during the switching processes in quantum antiferromagnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-04 20:00 EDT
Asliddin Khudoyberdiev, Götz S. Uhrig
The control of antiferromagnetic order can pave the way to large storage capacity as well as fast manipulation of stored data. Here achieving a steady-state of sublattice magnetization after switching is crucial to prevent loss of stored data. The present theoretical approach aims to obtain instantaneous stable states of the order after reorienting the Néel vector in open quantum antiferromagnets using time-dependent Schwinger boson mean-field theory. The Lindblad formalism is employed to couple the system to the environment. The quantum theoretical approach comprises differences in the effects of dephasing, originating from destructive interference of different wave vectors, and spin-lattice relaxation. We show that the spin-lattice relaxation results in an exponentially fast convergence to the steady-state after full ultrafast switching.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Gapless superconductivity from extremely dilute magnetic disorder in 2H-NbSe2-xSx
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-04 20:00 EDT
Jose Antonio Moreno, Mercè Roig, Víctor Barrena, Edwin Herrera, Alberto M. Ruiz, Samuel Mañas-Valero, Antón Fente, Anita Smeets, Jazmín Aragón, Yanina Fasano, Beilun Wu, Maria N. Gastiasoro, Eugenio Coronado, José J. Baldoví, Brian M. Andersen, Isabel Guillamón, Hermann Suderow
Most superconducting materials exhibit a vanishing density of states at the Fermi level and Anderson’s theorem posits that the superconducting gap is robust against nonmagnetic disorder. Although dilute magnetic impurities lead to localized in-gap states, these states typically have no bearing on the material’s bulk superconducting properties. However, numerous experiments reveal a finite density of states at the Fermi level in systems with an apparently negligible number of magnetic impurities. Here, using scanning tunneling microscopy and self-consistent Bogoliubov-de Gennes calculations, we find that gapless superconductivity emerges in 2H-NbSe2-xSx at remarkably low magnetic impurity concentrations. Furthermore, our density functional theory calculations and in-gap quasiparticle interference measurements demonstrate that the Se-S substitution significantly modifies the band structure. This modification favours nesting and dictates the in-gap scattering for x>0, in stark contrast to the dominant charge density wave interactions in pure 2H-NbSe2. Our findings reveal an unusual superconducting response to disorder and highlight the importance of incorporating material-specific band structures in the understanding of a superconductor’s response to even very low concentrations of magnetic impurities.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Precision high-speed quantum logic with holes on a natural silicon foundry platform
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-04 20:00 EDT
Isaac Vorreiter, Jonathan Y. Huang, Scott D. Liles, Joe Hillier, Ruoyu Li, Bart Raes, Stefan Kubicek, Julien Jussot, Sofie Beyne, Clement Godfrin, Sugandha Sharma, Danny Wan, Nard Dumoulin Stuyck, Will Gilbert, Chih Hwan Yang, Andrew S. Dzurak, Kristiaan De Greve, Alexander R. Hamilton
Silicon spin qubits in gate-defined quantum dots leverage established semiconductor infrastructure and offer a scalable path toward transformative quantum technologies. Holes spins in silicon offer compact all-electrical control, whilst retaining all the salient features of a quantum dot qubit architecture. However, silicon hole spin qubits are not as advanced as electrons, due to increased susceptibility to disorder and more complex spin physics. Here we demonstrate single-qubit gate fidelities up to 99.8% and a two-qubit gate quality factor of 240, indicating a physical fidelity limit of 99.7%. These results represent the highest performance reported in natural silicon to date, made possible by fast qubit control, exchange pulsing, and industrial-grade fabrication. Notably, we achieve these results in a near-identical device as used for highly reproducible, high-fidelity electron spin qubits. With isotopic purification and device-level optimisations in the future, our hole spin qubits are poised to unlock a new operation regime for quantum CMOS architectures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Hybrid magnon – Nambu-Goldstone excitations in topological superconductor/ferromagnetic insulator thin-film heterostructures
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-04 20:00 EDT
T. Karabassov, I. V. Bobkova, A. M. Bobkov, A. S. Vasenko, A. A. Golubov
We address a previously unexplored type of dynamical proximity effect that occurs in s-wave topological superconductor/ferromagnetic insulator (TS/FI) heterostructures. It is predicted that magnons in the FI and the Nambu-Goldstone (NG) collective superconducting phase mode in the TS are coupled, forming composite magnon-NG excitations. The mechanism of this coupling is associated with the complete spin-momentum locking of electrons in the helical surface state of the TS. The strength of the magnon-NG coupling is strongly anisotropic with respect to the mutual orientation of the magnon wave vector and the equilibrium magnetization of the FI. This effect provides a mechanism for the interconversion of spin signals and the spinless signals carried by collective superconducting excitations, thereby giving new impetus to the development of superconducting spintronics.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Quantum Geometry Phenomena in Condensed Matter Systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-04 20:00 EDT
Anyuan Gao, Naoto Nagaosa, Ni Ni, Su-Yang Xu
Quantum geometry, which describes the geometry of Bloch wavefunctions in solids, has become a cornerstone of modern quantum condensed matter physics. The quantum geometrical tensor encodes this geometry through two fundamental components: the quantum metric (real part) and the Berry curvature (imaginary part). While the Berry curvature gained prominence through its manifestation in the intrinsic anomalous Hall effect, recent advances have revealed equally significant effects arising from the quantum metric. This includes its signatures in nonlinear transport, superfluid density of flat-band superconductors, and nonlinear optical responses. These advances underscore how quantum geometry is reshaping our understanding of condensed matter systems, with far-reaching implications for future technologies. In this review, we survey recent progress in the field, focusing on both foundational concepts and emergent phenomena in transport and optics-with particular emphasis on the pivotal role of the quantum metric.
Strongly Correlated Electrons (cond-mat.str-el)
Your comments and suggestions are welcome! (62 pages, 28 figures)
The Bose-Hubbard polaron from weak to strong coupling
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-04 20:00 EDT
Tom Hartweg, Tanul Gupta, Guido Pupillo
We investigate the zero-temperature properties of a mobile impurity immersed in a bath of bosonic particles confined to a square lattice. We analyze the regimes of attractive and repulsive coupling between the impurity and the bath particles for different strengths of boson-boson interactions in the bath, using exact large-scale quantum Monte-Carlo simulations in the grand canonical ensemble. For weak coupling, the polaron mass ratio is found to decrease around the Mott insulator (MI) to superfluid (SF) transition of the bath, as predicted by recent theory, confirming the possible use of the impurity as a probe for the transition. For strong coupling in the MI regime, instead, the impurity is found to modify the bath density by binding to an extra bath particle or a hole, depending on the sign of the polaron-bath interactions. While the binding prevent the aforementioned use of the polaron mass ratio as an MI-SF transition probe, we show that it can be used instead as a probe of the binding itself. Our exact numerical results provide a benchmark for comparing lattice Bose polaron theories and are relevant for experiments with cold atoms trapped in optical lattices, where the presence of a confining harmonic potential can be modeled by a slowly varying local chemical potential.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
Theory of hybrid collective excitations in topological superconductor/ferromagnetic insulator heterostructures
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-04 20:00 EDT
T. Karabassov, I. V. Bobkova, A. M. Bobkov, A. S. Vasenko, A. A. Golubov
We develop a linear response theory for the dynamical proximity effect in topological superconductor/ferromagnetic insulator (TS/FI) hybrid structures. Our approach combines the nonequilibrium quasiclassical Keldysh-Usadel equations for the electronic Green’s functions in the TS with the Landau-Lifshitz-Gilbert equation governing the magnetization dynamics in the FI. Within this framework, we study the proximity-induced coupling between magnons and superconducting collective excitations. We find that the spin-momentum locking intrinsic to the surface state of the TS leads to a hybridization between the superconducting Nambu-Goldstone (phase) collective mode and magnons, resulting in the emergence of composite magnon-Nambu-Goldstone excitations. The dependence of the coupling strength on relevant physical parameters is analyzed both analytically and numerically. In contrast, we show that the Higgs (amplitude) mode does not couple to magnons at linear order and therefore does not participate in the formation of hybrid collective excitations.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Localized states and skin effect around non-Hermitian impurities in tight-binding models
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-04 20:00 EDT
We use the generalized Bloch theorem formalism of Alase {\it et al.} [{\it Phys. Rev. Lett.} {\bf 117} 076804 (2016)] to analyze simple one-dimensional tight-binding lattice systems connected by Hermitian bonds (all with the same hopping parameter $ t$ ), but containing one bond impurity which can be either Hermitian or non-Hermitian. We calculate the band structure, the bulk-boundary correspondence indicator ($ D_L(\epsilon)$ ) and analyze the eigenvalues of the lattice translation operator ($ z$ ), for each eigenstate. From the $ z$ values the generalized Brillouin zone can be reconstructed. If the impurity is Hermitian (and $ \mathcal{PT}$ -symmetric), we find a parameter regime in which two localized edge states separate from the tight-binding band. We then simulate a non-Hermitian impurity by keeping hopping in one direction of the bond impurity the same as the rest of the tight-binding system, and varying only its reciprocal. Again, we find a region with localized edge states, but in this case the energy eigenvalues are purely imaginary. We also find that in this case the two zero energy eigenvectors coalesce, hence this system is an exceptional line. We then perform an interpolative scan between the above two scenarios and find that there is an intermediate region exhibiting a non-Hermitian skin effect. In this region a macroscopic fraction of states acquire complex energy eigenvalues and exhibit localization towards the impurity. Our numerical results are supported by a detailed analysis of the solutions of the boundary/impurity equation.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas), Superconductivity (cond-mat.supr-con), Mathematical Physics (math-ph), Quantum Physics (quant-ph)
Wave-mixing cathodoluminescence microscopy of low-frequency excitations
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-04 20:00 EDT
Leila Prelat, Eduardo J. C. Dias, F. Javier García de Abajo
Nonlinear optical phenomena such as parametric amplification and frequency conversion are typically driven by external optical fields. Free electrons can also act as electromagnetic sources, offering unmatched spatial precision. Combining optical and electron-induced fields via the nonlinear response of material structures therefore holds potential for revealing new physical phenomena and enabling disruptive applications. Here, we theoretically investigate wave mixing between external light and the evanescent fields of free electrons, giving rise to inelastic photon scattering mediated by the second-order nonlinear response of a specimen. Specifically, an incident photon may be blue- or red-shifted, while the passing electron correspondingly loses or gains energy. These processes are strongly enhanced when the frequency shift matches an optical resonance of the specimen. We present a general theoretical framework to quantify the photon conversion probability and demonstrate its application by revealing far-infrared vibrational fingerprints of retinal using only visible light. Beyond its fundamental interest, this phenomenon offers a practical approach for spatially mapping low-frequency excitations with nanometer resolution using visible photon energies and existing electron microscopes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 5 figures, 37 references
A More Convex Ising Formulation of Max-3-Cut Using Higher-Order Spin Interactions
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-04 20:00 EDT
Robbe De Prins, Guy Van der Sande, Peter Bienstman, Thomas Van Vaerenbergh
Many combinatorial optimization problems (COPs) are naturally expressed using variables that take on more than two discrete values. To solve such problems using Ising machines (IMs) - specialized analog or digital devices designed to solve COPs efficiently - these multi-valued integers must be encoded using binary spin variables. A common approach is one-hot encoding, where each variable is represented by a group of spins constrained so that exactly one spin is in the “up” state. However, this encoding introduces energy barriers: changing an integer’s value requires flipping two spins and passing through an invalid intermediate state. This creates rugged energy landscapes that may hinder optimization. We propose a higher-order Ising formulation for Max-3-Cut, which is the smallest fundamental COP with multi-valued integer variables. Our formulation preserves valid configurations under single-spin updates. The resulting energy landscapes are smoother, and we show that this remains true even when the binary variables are relaxed to continuous values, making it well-suited for analog IMs as well. Benchmarking on such an IM, we find that the higher-order formulation leads to significantly faster solutions than the Ising baseline. Interestingly, we find that an empirical rescaling of some terms in the Ising formulation - a heuristic proposed in prior work - approaches the performance of the higher-order Ising formulation, underscoring the importance of empirical parameter tuning in COP encodings.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph), Adaptation and Self-Organizing Systems (nlin.AO), Cellular Automata and Lattice Gases (nlin.CG), Applied Physics (physics.app-ph)
11 pages, 8 figures, including appendices
Triplet correlations in superconductor/antiferromagnet heterostructures: dependence on type of antiferromagnetic ordering
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-04 20:00 EDT
G. A. Bobkov, V. A. Bobkov, I. V. Bobkova, A. M. Bobkov, A. A. Golubov
In recent years, a number of studies have predicted the emergence of a nontrivial proximity effect in superconductor/antiferromagnet (S/AF) heterostructures. This effect is of considerable interest for the efficient integration of antiferromagnetic materials into the fields of superconducting spintronics and electronics. A key element of this proximity effect is the Neel triplet correlations, initially predicted for S/AF heterostructures with checkerboard G-type antiferromagnetic ordering. However, various forms of antiferromagnetic ordering exist, and an important open question concerns the generalization of these results to such cases. In this paper, we develop a theory of the proximity effect in S/AF heterostructures with arbitrary two-sublattice antiferromagnetic ordering, aiming to clarify which antiferromagnets are capable of inducing triplet correlations and what structure these correlations may exhibit. We show that, in S/AF heterostructures with collinear compensated antiferromagnets, the dominant superconducting triplet correlations are of the checkerboard Neel type, as originally predicted for G-type antiferromagnets. In contrast, layered Neel triplet correlations, although potentially generated by layered antiferromagnets, are significantly weaker. Consequently, in S/AF heterostructures with layered antiferromagnetic ordering, the proximity-induced triplet correlations may exhibit either a checkerboard Neel or a conventional ferromagnetic structure, depending on the specific antiferromagnet and its orientation relative to the S/AF interface.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Low-Energy Boundary-State Emergence and Delocalization in Finite-sized Mosaic Wannier-Stark Lattices
New Submission | Other Condensed Matter (cond-mat.other) | 2025-08-04 20:00 EDT
Yi Kang, Zhenjia Yu, Xiumei Wang, Xingping Zhou
The mosaic Wannier Stark lattice has gained increasing prominence as a disorder free system exhibiting unconventional localization behavior induced by spatially periodic Stark potentials. In the infinite size limit, exact spectral analysis reveals an almost pure point spectrum. There is no true mobility edge, except for (M 1) isolated extended states, which are accompanied by weakly localized modes with diverging localization lengths. Motivated by this spectral structure, we investigate the mosaic Wannier Stark model under finite-size. In such systems, additional low energy boundary localized states emerge due to boundary residuals when the system length is not commensurate with the modulation period. These states are effectively distinguished and identified using the inverse participation ratio (IPR) and spatial expectation values. To explore their response to non-Hermitian perturbations, complex on site potentials are introduced to simulate gain and loss. As the non-Hermitian strength increases, only the weakly localized states undergo progressive delocalization, exhibiting a smooth crossover from localization to spatial extension.
Other Condensed Matter (cond-mat.other)
Amortized Clustering Assistant Classification of Anomalous Hybrid Floquet Modes in a Periodically Driven non-Hermitian Lattice
New Submission | Other Condensed Matter (cond-mat.other) | 2025-08-04 20:00 EDT
Yifei Xia, Xiumei Wang, Yali Li, Xingping Zhou
The interplay between Floquet periodically driving and non-Hermiticity could bring about intriguing novel phenomena with anomalous Floquet topological phases of a finite-size, tight-binding lattice model. How to efficiently investigate on quasi-energy and eigenfield of a non-Hermitian Floquet system with complicated driving protocol remains a challenging task. In this work, we define a somewhat complex driving protocol for a bipartite lattice system and discover two nontrivial topological phases that support Floquet {\pi} mode. Thereafter, we introduce unsupervised learning method in order to explore distribution features of system eigenfunctions under different magnitude of system energy gain/loss. We utilize the idea of amortized clustering and construct an algorithm selector that could dynamically upgrade with increasing gain/loss as input parameter. Proper employment of the selector enables us to reveal the regulation of dynamic localization from abundant possible wave function distribution in two-dimension lattice in another efficient way. In addition, our work provides a feasible methodology via machine learning method to assist in classification of Floquet modes.
Other Condensed Matter (cond-mat.other)
From Thermalization to Multifractality: Spin-Spin Correlation in Disordered $SU(2)$-Invariant 1D Heisenberg Spin Chains
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-08-04 20:00 EDT
Debasmita Giri, Julian Siegl, John Schliemann
We investigate spin correlations in one-dimensional $ SU(2)$ -invariant Heisenberg chains with exchange disorder for spin lengths $ S=1/2$ and $ S=1$ . In the weak-disorder regime, the eigenmodes of the spin-spin correlation matrix are delocalized, consistent with ergodic behavior. Under strong disorder, the system enters a quasi-localized multifractal phase characterized by exponentially decaying, dimer-like spin correlations. Finite-size scaling of the inverse participation ratios of the correlation-matrix eigenmodes yields a correlation dimension, $ D_2\approx 0.37-0.39$ , confirming the stability of a multifractal regime that is distinct from both the ergodic limit ($ D_2=1$ ) and the fully localized limit ($ D_2=0$ ).
Disordered Systems and Neural Networks (cond-mat.dis-nn)
10 pages, 10 figures
Two-photon-assisted collisions in ultracold gases of polar molecules
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-04 20:00 EDT
Charbel Karam, Gohar Hovhannesyan, Romain Vexiau, Maxence Lepers, Nadia Bouloufa-Maafa, Olivier Dulieu
We present a theoretical formalism to treat the ultracold dynamics of a pair of colliding polar molecules submitted to two laser fields. We express the dressed Hamiltonian including the dipole-dipole interaction of the colliding molecular pair, both in their ground and electronic excited states, as well as their interaction with the two laser fields. We apply adiabatic elimination of the electronic excited state to reduce the size of the dressed-state basis in which the dressed Hamiltoninan is expressed. In an application, we investigate the feasibility of two-photon collisional shielding between two \NaK molecules, which could be favored by the Raman resonance condition suppressing unwanted spontaneous emission and photon scattering. We demonstrate the influence of the laser Rabi frequencies on the dynamics through the computation of elastic, inelastic, and reactive collision rates.
Quantum Gases (cond-mat.quant-gas)
Electronic properties of Kagome metal YbV$_3$Sb$_4$: A First-Principles Study
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-04 20:00 EDT
D. Gurung, Keshav Shrestha, Shalika R. Bhandari, Samy Brahimi, Samir Lounis, D. P. Rai
We have investigated the vanadium-based Kagome metal YbV$ _3$ Sb$ _4$ using density functional theory (DFT) combined with the Wannier function analysis. We explore the electronic properties, de Haas-van Alphen (dHvA) effect and Fermi surface. The inclusion of spin-orbit coupling SOC induces the splitting of Yb-4f states, while its impact on the V-3d states is moderate. Furthermore, we have incorporated SOC+U, where U being the Hubbard parameter, which drastically changes the Yb-4f states creating additional splitting leading to three distinct peaks in the density of states (DOS). The V-3d atoms with the Kagome lattice contribute maximum to the transport properties, exhibits flat bands near the EF while being protected under SOC and U+SOC. Herein, we report the vulnerability of the Yb-4f states under SOC and U+SOC. Furthurmore, The Fermi surface is found to comprise of quasi-2D cylindrical sheets centered at the Gamma-point, along with smaller pockets near the Brillouin zone boundaries, which under combined U+SOC, a small spherical pocket emerges and the cylindrical sheet exhibits slight deformations. The dHvA frequencies reach as high as 70 kilotesla, which increase with tilt angle, exhibiting a nearly parabolic trend as expected for cylindrical orbits, while a low-frequency branch remains below 1 kT. Only the U+SOC case shows noticeable modification in both the Fermi surface and the dHvA oscillation. Crucially, the $ Z_2$ invariant calculation identifies YbV$ _3$ Sb$ _4$ as a strong topological metal ($ r_0 = 1$ ). These findings not only advance our understanding of the underlying quantum phenomena in rare-earth Kagome systems, but also establish YbV$ _3$ Sb$ _4$ as a compelling and promising platform for exploring intertwined topology and electron correlations in kagome lattices, thereby offering valuable insights for engineering quantum phases in layered materials.
Strongly Correlated Electrons (cond-mat.str-el)
Lippmann-Schwinger Approach for Accurate Photoelectron Wavefunctions and Angle-Resolved Photoemission Spectra from First Principles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-04 20:00 EDT
We present a conceptually simple and technically straightforward method for calculating photoelectron wavefunctions that is easily integrable with standard wavefunction-based density-functional-theory packages. Our method is based on the Lippmann-Schwinger equation, naturally incorporating the boundary condition that the final photoelectron state must satisfy. The calculated results are in good agreement with the measured photon-energy- and polarization-dependence of the angle-resolved photoemission spectroscopy (ARPES) of graphene, the photon-energy-dependent evolution of the so-called dark corridor arising from the pseudospin, and WSe\textsubscript{2}, the circular dichroism reflecting the hidden orbital polarization. Our study opens doors to do-it-yourself simulations of ARPES with standard density-functional-theory packages, of crucial importance in the era of ``quantum materials,’’ whose key experimental tool is ARPES.
Materials Science (cond-mat.mtrl-sci)
8 pages, 2 figures
Phys. Rev. Lett. 135, 056403 (2025)
Screw Symmetry, Chiral Hydrodynamics and Odd Instability in Active Cholesterics
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-04 20:00 EDT
Gareth P. Alexander, S.J. Kole, Ananyo Maitra, Sriram Ramaswamy
Active cholesterics are chiral in both their structure, which has continuous screw symmetry, and their active stresses, which include contributions from torque dipoles. Both expressions of chirality give rise to curl forces in the hydrodynamics, which we derive from the active Ericksen-Leslie equations using a geometric approach. This clarifies the hydrodynamics of continuous screw symmetry and provides an example of generalised odd elastic forces that originate from an equilibrium free energy. We discuss also the nonlinear structure of the active hydrodynamics in terms of the Eulerian displacement field of the cholesteric pseudolayers. For the active instability, screw symmetry generates a contribution of chiral activity to the linearised pseudolayer hydrodynamics that is absent in materials with chiral activity but achiral structure. When the two forms are sufficiently antagonistic, this term produces a new active instability with threshold and characteristic wavevector distinct from those of the active Helfrich-Hurault instability in chiral active smectics. Finally, we comment on the isotropic chiral hydrodynamics of materials with three-dimensional screw symmetry.
Soft Condensed Matter (cond-mat.soft)
12 pages, 3 figures
XANES absorption spectra of penta-graphene and penta-SiC2 with different terminations: a computational study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-04 20:00 EDT
Andrea Pedrielli, Tommaso Morresi, Simone Taioli
In recent research, penta-graphene and penta-SiC2 have emerged as innovative 2D materials consisting exclusively of pentagons. However, there is still a significant gap in the theoretical characterization of these materials, which hinders progress in their synthesis and potential technological applications. This study aims to close this gap by investigating the X-ray absorption near-edge spectroscopy (XANES) of these materials through ab initio calculations. In particular, we analyze the XANES spectra of penta-graphene in its pristine, hydrogenated, and hydroxylated states, and we investigate the effects of substitution by a single silicon in both penta-graphene and pentagraphane. In addition, we calculate the XANES spectra for pristine and hydrogenated penta-SiC2. This work sets the stage for the possible identification of penta-graphene and penta-SiC2 phases by X-ray spectroscopy at the experimental level and lays the foundation for the future engineering of the absorption properties of these materials in optical devices.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Rigid body rotation and chiral reorientation combine in filamentous E. coli swimming in low-Re flows
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-04 20:00 EDT
Richard Z. DeCurtis, Yongtae Ahn, Jane Hill, Sara M. Hashmi
Antibiotic doses below a minimum inhibitory concentration turn off bacteria cell division, but not cell growth. As a result, rod-like bacteria including E. coli can elongate many times their original length without increasing their width. The swimming behavior of these filamentous bacteria through small channels may provide insights into how antibiotic-resistant bacteria swim to channel walls. Such swimming behaviors in settings like hospital tubing may facilitate adhesion, biofilm formation and infection. Despite the importance of understanding the behavior of bacteria not killed by antibiotics, the swimming of filamentous bacteria in external flows has not received much attention. We study the swimming of stressed, filamentous E. coli. In quiescence, highly elongated E. coli swim with a sinusoidal undulation, suggesting rigid body rotation of the long, slightly segmented cell bodies. In low Reynolds number pressure-driven flows through a microchannel, undulation becomes irregular and may stop and start within a particular bacteria trajectory. We refer to this behavior in flow as wiggling.' Rigid body rotation persists in flow, appearing as a high frequency change in body orientation on top of a slower frequency of reorientation. Chiral reorientation can explain the slower reorientation. We quantify swimming in two flow rates and observe both rheotaxis and preferential orientation of bacteria bodies. We find that the faster flow constrains wiggling bacteria trajectories and orientations more than slower flow does. Interestingly, not all bacteria in flow wiggle. Populations of non-wiggling’ filamentous E. coli follow streamlines, without preferential orientation, flowing faster than wigglers. Non-wigglers do not behave like chiral rods propelled by flagellar bundles, but like rigid rods. Differentiating these populations may have important implications for understanding motility loss.
Soft Condensed Matter (cond-mat.soft)
13 pages, 7 figures, SI pdf, SI videos
On the interaction of dilatancy and friction in the behavior of fluid-saturated sheared granular materials: a coupled Computational Fluid Dynamics–Discrete Element Method study
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-04 20:00 EDT
Bimal Chhushyabaga, Behrooz Ferdowsi (Department of Civil and Environmental Engineering, University of Houston)
Frictional instabilities in fluid-saturated granular materials underlie critical natural hazards such as submarine landslides and earthquake initiation. Distinct failure behaviors emerge under subaerial and subaqueous conditions due to the coupled effects of mechanical deformation, interparticle friction, and fluid interactions. This study employs three-dimensional coupled Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) simulations to investigate the collapse and runout dynamics of dense and loose granular assemblies across these settings. Parametric analyses reveal that pore pressure evolution plays a central role in governing failure mechanisms: dense assemblies stabilize through dilation, while loose assemblies undergo rapid compaction and fluidization, particularly under subaqueous conditions. Spatiotemporal analyses of coarse-grained fields further highlight strain-rate-dependent behavior driven by evolving porosity and effective stress. Both environments exhibit rate-strengthening behavior that scales with the inertial number (In) and viscous number (Iv), though driven by distinct mechanisms: subaerial systems are dominated by interparticle contact networks, whereas subaqueous systems are influenced by fluid drag, pore-pressure buildup, and lubrication. An analytical solution for excess pore pressure is compared with breaching-induced pressure distributions from CFD-DEM simulations, using input parameters derived from numerical triaxial DEM tests. The model captures fluid-particle coupling effectively, reproducing comparable excess pore pressures at steady state, while early-time discrepancies underscore the complexities of transient interactions. These findings advance the understanding of failure mechanics in saturated granular media and support the development of physics-based models for mitigating hazards associated with subaqueous granular flows.
Soft Condensed Matter (cond-mat.soft), Geophysics (physics.geo-ph)
On the criticality of the configuration-space statistical geometry
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-04 20:00 EDT
Yu-Jing Liu, Wen-Yu Su, Yong-Feng Yang, Nvsen Ma, Chen Cheng
While phases and phase transitions are conventionally described by local order parameters in real space, we present a unified framework characterizing the phase transition through the geometry of configuration space defined by the statistics of pairwise distances $ r_H$ between configurations. Focusing on the concrete example of Ising spins, we establish crucial analytical links between this geometry and fundamental real-space observables, i.e., the magnetization and two-point spin correlation functions. This link unveils the universal scaling law in the configuration space: the standard deviation of the normalized distances exhibits universal criticality as $ \sqrt{\mathrm{Var}(r_H)}\sim L^{-2\beta/\nu}$ , provided that the system possesses zero magnetization and satisfies $ 4\beta/\nu < d$ . Numerical stochastic series expansion quantum Monte Carlo simulations on the transverse-field Ising model (TFIM) validate this scaling law: (i) It is perfectly validated in the one-dimensional TFIM, where all theoretical criteria are satisfied; (ii) Its robustness is confirmed in the two-dimensional TFIM, where, despite the theoretical applicability condition being at its marginal limit, our method robustly captures the effective scaling dominated by physical correlations; (iii) The method’s specificity is demonstrated via a critical control experiment in the orthogonal $ \hat{\sigma}^x$ basis, where no long-range order exists, correctly reverts to a non-critical background scaling. Moreover, the distribution probability $ P(r_H)$ parameterized by the transverse field $ h$ forms a one-dimensional manifold. Information-geometric analyses, particularly the Fisher information defined on this manifold, successfully pinpoint the TFIM phase transition, regardless of the measuring basis.
Statistical Mechanics (cond-mat.stat-mech)
12 pages, 10 figures
Persistent spin textures, altermagnetism and charge-to-spin conversion in metallic chiral crystals TM${3}$X${6}$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-04 20:00 EDT
Karma Tenzin, Berkay Kilic, Raghottam Sattigeri, Zhiren He, Chao Chen Ye, Marcio Costa, Marco Buongiorno Nardelli, Carmine Autieri, Jagoda Slawinska
Chiral crystals, due to the lack of inversion and mirror symmetries, exhibit unique spin responses to external fields, enabling physical effects rarely observed in high-symmetry systems. Here, we show that materials from the chiral dichalcogenide family TM$ _3$ X$ _6$ (T = 3d, M = 4d/5d, X = S) exhibit persistent spin texture (PST) - unidirectional spin polarization of states across large regions of the reciprocal space - in their nonmagnetic metallic phase. Using the example of NiTa$ _{3}$ S$ _{6}$ and NiNb$ _{3}$ S$ _{6}$ , we show that PSTs cover the full Fermi surface, a rare and desirable feature that enables efficient charge-to-spin conversion and suggests long spin lifetimes and coherent spin transport above magnetic ordering temperatures. At low temperatures, the materials that order antiferromagnetically become chiral altermagnets, where spin textures originating from spin-orbit coupling and altermagnetism combine in a way that sensitively depends on the orientation of the Neel vector. Using symmetry analysis and first-principles calculations, we classify magnetic ground states across the family, identify cases with weak ferromagnetism, and track the evolution of spin textures and charge-to-spin conversion across magnetic phases and different Neel vector orientations, revealing spin transport signatures that allow one to distinguish Neel vector directions. These findings establish TM$ _3$ X$ _6$ as a tunable platform for efficient charge-to-spin conversion and spin transport, combining structural chirality, persistent spin textures, and altermagnetism.
Materials Science (cond-mat.mtrl-sci)
Magnetic Octupole Hall Effect in d-Wave Altermagnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-04 20:00 EDT
Order parameters not only characterize symmetry-broken equilibrium phases but also govern transport phenomena in the nonequilibrium regime. Altermagnets, a class of magnetic systems integrating ferromagnetic and antiferromagnetic features, host multipolar orders in addition to dipolar Neel order. In this work, we demonstrate the multipole Hall effect in d-wave altermagnets–a transverse flow of multipole moments induced by an electric field. Using symmetry analysis and linear response theory, we show that the magnetic octupole Hall effect persists even in symmetries where the spin-splitter effect is forbidden and thus provides a robust experimental signature. In addition, we identify a sizable electric quadrupole Hall effect, originating from quadrupole splittings in the band structure. Our results expand the family of Hall effects to include higher-order multipolar responses and establish altermagnets as a versatile platform for exploring multipole transport beyond spin and orbital degrees of freedom.
Materials Science (cond-mat.mtrl-sci)
7 pages, 3 figures
Chiral anomaly-induced nonlinear Hall effect in spin-orbit coupled noncentrosymmetric metals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-04 20:00 EDT
Gautham Varma K, Mohd. Hashim Raza, Azaz Ahmad
Recent studies have shown that chiral anomaly is not limited to WSMs, but are also shown by a larger class of materials called spin orbit coupled noncentrosymmetric metals (SOC-NCMs),which has shed more insight into the origin of chiral anomaly as a Fermi surface property rather than a nodal property. In this study, we explore nonlinear transport responses in SOC-NCMswithin the framework of semiclassical dynamics, employing the Maxwell-Boltzmann transport theory augmented by charge conservation and momentum-dependent scattering processes. We take into account both non-magnetic and magnetic impurity scattering mechanisms. We demonstrate that the chiral-anomaly-induced nonlinear Hall (CNLH) response exhibits a characteristic quadratic dependence on the applied magnetic field and remains negative for both types of impurities. We find that magnetic scatterers leading to enhanced/suppressed interband scattering modifies the magnitude of the signal, but does not affect its qualitative behavior. In contrast, the presence of tilt in the band dispersion induces a pronounced anisotropic response, including a magnetic-field-direction dependent sign reversal that can be categorized into weak and strong regimes. Furthermore, the CNLH response shows substantial directional anisotropy governed by the relative orientation of the external magnetic field and the tilt vector. Our findings will be helpful in designing the experimental setup to get direction-dependent conductivity, which can be tuned externally with the help of magnetic impurity sites.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 12 figures. Comments are welcome