CMP Journal 2025-07-14
Statistics
Nature: 1
Nature Nanotechnology: 1
Nature Physics: 1
arXiv: 60
Nature
Microbiota-driven antitumour immunity mediated by dendritic cell migration
Original Paper | Bacterial host response | 2025-07-13 20:00 EDT
Nina Yi-Tzu Lin, Shota Fukuoka, Shohei Koyama, Daisuke Motooka, Dieter M. Tourlousse, Yuko Shigeno, Yuki Matsumoto, Hiroyuki Yamano, Kazutoshi Murotomi, Hideyuki Tamaki, Takuma Irie, Eri Sugiyama, Shogo Kumagai, Kota Itahashi, Tokiyoshi Tanegashima, Kaori Fujimaki, Sachiko Ito, Mariko Shindo, Takahiro Tsuji, Hiroaki Wake, Keisuke Watanabe, Yuka Maeda, Tomohiro Enokida, Makoto Tahara, Riu Yamashita, Takao Fujisawa, Motoo Nomura, Akihito Kawazoe, Koichi Goto, Toshihiko Doi, Kohei Shitara, Hiroyuki Mano, Yuji Sekiguchi, Shota Nakamura, Yoshimi Benno, Hiroyoshi Nishikawa
Gut microbiota influence the antitumour efficacy of immune checkpoint blockade1,2,3,4,5,6, but the mechanisms of action have not been fully elucidated. Here, we show that a new strain of the bacterial genus Hominenteromicrobium (designated YB328) isolated from the faeces of patients who responded to programmed cell death 1 (PD-1) blockade augmented antitumour responses in mice. YB328 activated tumour-specific CD8+ T cells through the stimulation of CD103+CD11b- conventional dendritic cells (cDCs), which, following exposure in the gut, migrated to the tumour microenvironment. Mice showed improved antitumour efficacy of PD-1 blockade when treated with faecal transplants from non-responder patients supplemented with YB238. This result suggests that YB328 could function in a dominant manner. YB328-activated CD103+CD11b- cDCs showed prolonged engagement with tumour-specific CD8+ T cells and promoted PD-1 expression in these cells. Moreover, YB238-augmented antitumour efficacy of PD-1 blockade treatment was observed in multiple mouse models of cancer. Patients with elevated YB328 abundance had increased infiltration of CD103+CD11b- cDCs in tumours and had a favourable response to PD-1 blockade therapy in various cancer types. We propose that gut microbiota enhance antitumour immunity by accelerating the maturation and migration of CD103+CD11b- cDCs to increase the number of CD8+ T cells that respond to diverse tumour antigens.
Bacterial host response, Cancer microenvironment, Immunotherapy
Nature Nanotechnology
Strain-induced crumpling of graphene oxide lamellas to achieve fast and selective transport of H2 and CO2
Original Paper | Chemical engineering | 2025-07-13 20:00 EDT
Pengxiang Zhang, Qian Wang, Yixin Zhang, Mo Lin, Xin Zhou, Ashish David, Andrey Ustyuzhanin, Musen Chen, Mikhail I. Katsnelson, Maxim Trubyanov, Kostya S. Novoselov, Daria V. Andreeva
Graphene oxide (GO) membranes offer high selectivity and energy-efficient gas separation. However, their dense, layered structure and tortuous diffusion paths limit permeability, posing a barrier to industrial use. Here we present a method to enhance selectivity and permeability, maintaining the structural stability of such membranes. With an industrially friendly manufacturing method, we produce crumpled GO membranes with gas diffusion pathways controlled by a multidomain structure. These membranes achieve H2 permeability of approximately 2.1 × 104 barrer, significantly surpassing the permeability of flat lamellar GO membranes, which is below 100 barrer. Its H2/CO2 selectivity of 91 outperforms current membrane technologies. In addition, the crumpled membranes demonstrate stability under harsh conditions (-20 °C, 96% relative humidity), a critical requirement for practical applications. This work addresses the long-standing permeability-selectivity trade-off and establishes a robust, scalable platform for integrating two-dimensional materials into membrane technology for real-world applications.
Chemical engineering, Two-dimensional materials
Nature Physics
Entanglement accelerates quantum simulation
Original Paper | Quantum information | 2025-07-13 20:00 EDT
Qi Zhao, You Zhou, Andrew M. Childs
Quantum entanglement is an essential feature of many-body systems that impacts both quantum information processing and fundamental physics. Classical simulation methods can efficiently simulate many-body states with low entanglement, but struggle as the degree of entanglement grows. Here we investigate the relationship between quantum entanglement and quantum simulation, and show that product formula approximations for simulating many-body systems can perform better for entangled systems. We establish an upper bound for algorithmic error in terms of entanglement entropy that is tighter than previous results, and develop an adaptive simulation algorithm that incorporates measurement gadgets to estimate the algorithmic error. This shows that entanglement is not only an obstacle to classical simulation, but also a feature that can accelerate quantum algorithms.
Quantum information, Quantum simulation
arXiv
Long-Term Stability of Superconducting Metal Superhydrides
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-14 20:00 EDT
Vasily S. Minkov, Mikhail A. Kuzovnikov, Panpan Kong, Alexander P. Drozdov, Feng Du, Jiafeng Yan, Jaeyong Kim, Stella Chariton, Vitali B. Prakapenka, Mohamed Mezouar, Björn Wehinger, G. Alexander Smith, Fedor F. Balakirev, Evgeny F. Talantsev
Zhou et al., in their recent publication (Nat. Commun. 16, 1135, 2025), reported the synthesis of lanthanum superhydride, LaHx (x = 10.2-11.1), by laser heating LaH3 with NH3BH3 at a pressure of 170 GPa and investigated the temporal evolution of the NMR spectra of the reaction products. They observed a gradual decrease in the 1H-NMR signal intensity assigned to the synthesized metal hydride, accompanied by an increase in molecular hydrogen within the sample chamber over a period of 50 days. Based on these observations, the authors concluded that LaH10 progressively decomposes into LaH3 and H2 within two months after synthesis at its formation pressure of 170 GPa. Here, we demonstrate that, under their formation conditions, metal superhydrides are thermodynamically more stable than metal trihydrides. Furthermore, we present direct experimental evidence - based on X-ray diffraction and four-probe electrical resistance measurements - confirming the stability of both the crystal lattice and high-temperature superconducting properties of the Fm-3m-LaH10 phase for more than five years. This long-term stability is consistent with predictions from quantum chemistry calculations.
Superconductivity (cond-mat.supr-con)
7 Pages, 3 Figures. Comment on arXiv:2408.13419 / doi: https://doi.org/10.1038/s41467-025-56033-3
Temperature
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-14 20:00 EDT
Conversations about weather, environment, health, cuisine, and even politics, all involve the word “temperature”. It was an attempt to understand the working of heat engines that gave the temperature a clear definition. In this Note we put the equilibrium-thermodynamics definition into a larger context of the multiscale thermodynamics, the multiscale rate thermodynamics, and nonphysical environments.
Statistical Mechanics (cond-mat.stat-mech)
12 pages, no figure
Fractional Thouless pumping of solitons: a unique manifestation of bulk-edge correspondence of nonlinear eigenvalue problems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
Recent foundational studies have established the bulk-edge correspondence for nonlinear eigenvalue problems using auxiliary eigenvalues $ \hat{H}\Psi=\omega S(\omega)\Psi$ , spanning both linear [T. Isobe et al., Phys. Rev. Lett. 132, 126601 (2024)] and nonlinear [Chenxi Bai and Zhaoxin Liang, Phys. Rev. A. 111, 042201 (2025)] Hamiltionians. This raises a fundamental question: Can eigenvalue nonlinearity generate observable physical phenomena absent in conventional approaches ($ \hat{H}\Psi=E\Psi$ )? In this work, we demonstrate the first uniquely nonlinear manifestation of this correspondence: fractional Thouless pumping of solitons. Through systematic investigation of nonlinear Thouless pumping in an extended Rice-Mele model with next-nearest-neighbor (NNN) couplings, we discover that the NNN parameters can induce fractional topological phases despite quantized topological invariants from conventional approaches. Crucially, these fractional phases are explained within the auxiliary eigenvalue framework, linking nonlinear spectral features directly to bulk-boundary correspondence. This work reveals novel phenomena emerging from the interplay between nonlinearity and NNN couplings, providing key insights for designing topological insulators and controlling quantum edge states in nonlinear regimes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas)
11 pages, 8 figures. arXiv admin note: text overlap with arXiv:2501.02478
Ultrasensitive Magnetometer based on Cusp Points of the Photon-Magnon Synchronization Mode
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
Xinlin Mi, Jinwei Rao, Lijun Yan, Xudong Wang, Bingbing Lyu, Bimu Yao, Shishen Yan, Lihui Bai
Ultrasensitive magnetometers based on spin resonances have led to remarkable achievements. However, the gyromagnetic ratios of these spin resonances that determine the responsivity of magnetometers to weak magnetic fields are inherently constrained by the Land$ \acute{e}$ g-factor of particles, such as the electron, with a constant gyromagnetic ratio of $ \gamma_e=2\pi\times28$ GHz/T. Here, we demonstrate an ultrasensitive magnetometer based on the cusp point (CP) of photon-magnon synchronization modes (PMSMs). The PMSM’s gyromagnetic ratio at the CP is enhanced to $ 37\gamma_e$ and further amplified to $ 236\gamma_e$ by utilizing the sixth-order oscillating mode of the PMSM. Moreover, the emission linewidth of the PMSM can be reduced to 0.06 Hz, resulting in excellent sensitivity to weak magnetic fields. These outstanding properties position our magnetometer to potentially achieve superior sensitivity to conventional magnetometers. Our work introduces a cost-effective prototype for the next generation of magnetometry, and may advance scientific research and technologies that rely on ultrasensitive magnetic field detection.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
Quantum theory of nonlinear electromagnetic response
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
In recent years, the investigation of nonlinear electromagnetic responses has received significant attention due to its potential for elucidating the quantum properties of matter. Although remarkable progress has been achieved in developing quantum theories of nonlinear responses to electric field, a comprehensive quantum theory framework that systematically addresses nonlinear responses to both electric and magnetic fields has yet to be thoroughly discussed. Here, we present a systematic quantum theory of nonlinear electromagnetic response using the Matsubara Green’s function approach, which explicitly incorporates the wave vector dependence of external electromagnetic fields. We provide diagrammatic representation and reveal the general properties of transport coefficients. We apply our theory to second-order responses, deriving the nonlinear Hall effects and magneto-nonlinear Hall effects in both time-reversal symmetric and time-reversal breaking systems. These effects stem from diverse quantum geometric sources. Additionally, we analyze the contributions arising from the Zeeman interaction. Our work presents a unified quantum theory of nonlinear electromagnetic response, paving the way for further exploration of novel phenomena in this field.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
27 pages, 2 figures
Electric and spin current vortices in altermagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
A.A. Herasymchuk, Karl Bergson Hallberg, Erik Wegner Hodt, Jacob Linder, E.V. Gorbar, Pavlo Sukhachov
Altermagnets constitute a class of collinear magnets with momentum-dependent spin splitting and vanishing net magnetization. Direct observation of the characteristic altermagnetic spin splitting, however, remains challenging. Indirect signatures can be obtained via transport studies, which so far have only considered homogeneous fields driving currents. We propose to leverage nonuniform electric fields and spin density gradients to probe the shape and the spin polarization of altermagnetic Fermi surfaces via transport measurements. By using both a semiclassical Boltzmann approach and a lattice Keldysh formalism, we show that altermagnets excite swirling electric and spin currents whose profiles depend on the relative orientation of altermagnetic lobes with respect to the sample boundaries. These currents can be measured via magnetometry techniques. Unlike previous proposals considering the hydrodynamic regime of transport, swirling currents are observed even in the Ohmic regime and rely exclusively on the altermagnetic spin splitting, with no swirls observed in ferromagnets. The electric and spin current vortices predicted here provide a unique altermagnetic signature in an experimentally accessible setup.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9+12 pages, 4+10 figures
Partial suppression of magnetism in the square lattice SU(3) Hubbard model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-14 20:00 EDT
Samuel Bird, Sebastian Huber, Jannes Nys
The SU(N) Hubbard model is a natural extension of the SU(2) model. However, even the N=3 case remains poorly understood. We report a substantially new ground-state phase diagram of the square lattice SU(3) Fermi-Hubbard model. Using a backflow ansatz, we identify strong signatures of a Mott transition and a subsequent magnetic transition, and the suppression of a previously predicted magnetic phase. We study the hole-doped model, identifying a transition from magnetic to paramagnetic behavior in the strong-coupling regime. Our findings offer a qualitatively new ground state picture. More broadly, our work suggests a path to study general SU(N) Hubbard models with arbitrary filling and geometry.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Gases (cond-mat.quant-gas)
10 pages, 8 figures
Diagonal Isometric Form for Tensor Product States in Two Dimensions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-14 20:00 EDT
Benjamin Sappler, Masataka Kawano, Michael P Zaletel, Frank Pollmann
Isometric tensor product states (isoTPS) generalize the isometric form of the one-dimensional matrix product states (MPS) to tensor networks in two and higher dimensions. Here, we introduce an alternative isometric form for isoTPS by incorporating auxiliary tensors to represent the orthogonality hypersurface. We implement the time evolving block decimation (TEBD) algorithm on this new isometric form and benchmark the method by computing ground states and the real time evolution of the transverse field Ising model in two dimensions on large square lattices of up to 1250 sites. Our results demonstrate that isoTPS can efficiently capture the entanglement structure of two-dimensional area law states. The short-time dynamics is also accurately reproduced even at the critical point. Our isoTPS formulation further allows for a natural extension to different lattice geometries, such as the honeycomb or kagome latice.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
14 pages, 14 figures
Long range to short range crossover in one dimension
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-14 20:00 EDT
Mrinal Sarkar, Nicolò Defenu, Tilman Enss
This work investigates the critical behavior of one-dimensional systems with long-range (LR) interactions, focusing on the crossover to short-range (SR) universality. Through large-scale Monte Carlo simulations of self-avoiding Lévy flights on a 1D lattice, we compute the anomalous dimension \eta, the correlation length exponent \nu, and the susceptibility exponent \gamma across a wide range of LR decay parameters \sigma. Our results provide strong numerical evidence that supports Sak’s scenario. They identify the crossover at \sigma^\ast = 1 and demonstrate the continuity of critical exponents across this point, with strong corrections to scaling. The study also reveals deviations from Flory-type scaling predictions and discusses the limitations of effective dimension approaches in general. These findings clarify the nature of the LR-SR crossover in low-dimensional systems and open avenues for exploring criticality in disordered and complex networks.
Statistical Mechanics (cond-mat.stat-mech)
9 (5+4) pages, 7 (4+3) figures
Charge distribution and magnetism in bilayer La$_3$Ni$_2$O$_7$: a hybrid functional study
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-14 20:00 EDT
Kateryna Foyevtsova, Ilya Elfimov, George A. Sawatzky
An accurate understanding of the ground state electronic properties of La$ _3$ Ni$ _2$ O$ _7$ , a high-temperature superconductor under pressure, is key for unveiling the origin of its superconductivity. In this paper, we conduct a theoretical study of the electronic structure of the bilayer polymorph of La$ _3$ Ni$ _2$ O$ 7$ using the hybrid functional approach, which is well suited to tackle the non-local correlation effects arising in this system from the molecular orbital splitting of the Ni $ 3d{3z^2-r^2}$ states inside Ni-Ni dimers. Our calculations reveal that bilayer La$ _3$ Ni$ _2$ O$ _7$ is a strongly correlated magnetic system with robust Ni spin moments. Spin moments on individual Ni sites take on unusually small values because of the electron delocalization over molecular orbitals involving multiple Ni and O sites. We further find that the magnetism of bilayer La$ _3$ Ni$ 2$ O$ 7$ is intimately linked with charge distribution between different Ni and O orbitals. Two distinct regimes are identified in this regard. In one, molecular orbital physics drives the Ni $ 3d{x^2-y^2}$ band towards half-filling, which is a well-established condition for unconventional high-temperature superconductivity upon hole doping in cuprates. In the other, the Ni $ 3d{x^2-y^2}$ band is quarter-filled favouring spin- and charge-density wave states and Ni-O bond-disproportionation, which is consistent with several recent experimental claims. It is possible that superconductivity in La$ _3$ Ni$ _2$ O$ _7$ occurs as a result of a pressure-induced transition between these two competing regimes. Since none of the low energy phases discovered in this study are metallic, non-stoichiometry would be required for superconductivity to occur.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
Phonon mode splitting and phonon anomaly in multiband electron systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
We investigate the topological consequences of coupling chiral fermions to local, dispersionless phonons. This interaction induces a splitting of the phonon spectrum into three bands: a flat band and two bands with linear dispersion, all of which are degenerate at a nodal point located at zero wavevector. The flat band exhibits vanishing Berry curvature, while the linearly dispersing bands carry nontrivial topological features. Their Berry curvature fields assume a hedgehog-like structure in momentum space, analogous to monopole configurations, and reflect the chirality of the underlying fermionic system. Moreover, the effective phonon response reveals a phonon parity anomaly, observable as a discontinuity in the phonon current. This anomaly originates from the singularities of the fermion Green’s function and signals the transfer of topological information from fermions to phonons. Our results demonstrate that phonon currents provide a direct probe of electronic chirality and topological structures. The framework offers a foundation for extending topological concepts to interacting bosonic systems and may guide the engineering of phononic materials with tunable geometric and topological properties.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
11 pages, 3 figures
Exciting terahertz magnons with amplitude modulated light: spin pumping, squeezed states, symmetry breaking and pattern formation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
Egor I. Kiselev, Jonas F. Karcher, Mark S. Rudner, Rembert Duine, Netanel H. Lindner
We show how amplitude modulated, coherent high-frequency drives can be used to access otherwise difficult to reach collective resonances and off-resonantly induce parametric instabilities. In particular, we demonstrate that difficult to access antiferromagnetic resonances in the THz range can be parametrically excited with signals at optical frequencies via a mechanism that we call Modulated Floquet Parametric Driving (MFPD). We study spin pumping and the formation of entangled, two-mode squeezed magnon pairs in anisotropic antiferromagnets under MFPD. Furthermore, we show that MFPD induces transitions to symmetry breaking steady-states in which dynamical spin patterns are formed by resonant magnon pairs.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Tunable chiral and nematic states in the triple-Q antiferromagnet Co$_{1/3}$TaS$_2$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-14 20:00 EDT
Erik Kirstein, Pyeongjae Park, Woonghee Cho, Cristian D. Batista, Je-Geun Park, Scott A. Crooker
Complex spin configurations in magnetic materials, ranging from collinear single-Q to noncoplanar multi-Q states, exhibit rich symmetry and chiral properties. However, their detailed characterization is often hindered by the limited spatial resolution of neutron diffraction techniques. Here we employ magnetic circular dichroism (MCD) and magnetic linear dichroism (MLD) to investigate the triangular lattice antiferromagnet Co$ _{1/3}$ TaS$ _2$ , revealing three-state (Z3) nematicity and also spin chirality across its multi-Q magnetic phases. At intermediate temperatures, the presence of MLD identifies nematicity arising from a single-Q stripe phase, while at high magnetic fields and low temperatures, a phase characterized solely by MCD emerges, signifying a purely chiral non-coplanar triple-Q state. Notably, at low temperatures and small fields, we discover a unique phase where both chirality and nematicity coexist. A theoretical analysis based on a continuous multi-Q manifold captures the emergence of these distinct magnetic phases, as a result of the interplay between four-spin interactions and weak magnetic anisotropy. Additionally, MCD and MLD microscopy spatially resolves the chiral and nematic domains. Our findings establish Co$ _{1/3}$ TaS$ _2$ as a rare platform hosting diverse multi-Q states with distinct combinations of spin chirality and nematicity while demonstrating the effectiveness of polarized optical techniques in characterizing complex magnetic textures.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
23 pages total, 5 figures and 9 Supplementary figures
Off-resonant light-induced topological phase transition and thermoelectric transport in semi-Dirac materials
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
Vassilios Vargiamidis, P. Vasilopoulos, Neophytos Neophytou
We show that a semi-Dirac (SD) system with an inversion symmetry breaking mass exhibits a topological phase transition when irradiated with off-resonant light. Using Floquet theory, we derive the band structure, Chern numbers, phase diagram, and we show that as the light intensity is swept at fixed mass, the SD system undergoes normal-Chern-normal insulator transition. Along the phase boundaries we observe single semi-Dirac-cone (SSDC) semimetal states in which one SD cone is gapless and the other gapped. The nontrivial Berry curvature distribution $ \Omega(\mathbf{k}) \neq -\Omega ( - \mathbf{k} )$ generates an orbital magnetization $ M$ and anomalous Nernst ($ \alpha_{xy}$ ) and thermal Hall ($ \kappa_{xy}$ ) conductivities. We show that $ M$ remains constant as the Fermi level $ E_F$ scans the insulating gap, but it changes linearly with it in the Chern insulator (CI) phase, as expected. In the normal insulator phase, we find that $ \alpha_{xy}$ exhibits a dip-peak profile which is reversed in the CI phase. We also find that switching the light’s circular polarization from left to right induces a sign change in $ M$ , $ \alpha_{xy}$ , and $ \kappa_{xy}$ , regardless of the topological phase, thereby allowing us to reverse the direction of flow of the transverse charge and heat currents. Further, we evaluate the components of the charge ($ \sigma_{aa}$ ), thermoelectric ($ \alpha_{aa}$ ), and thermal ($ \kappa_{aa}$ ) conductivity tensors ($ a=x, y$ ) and examine the effect of light on them. With a linear dispersion along the $ y$ -direction, we find that $ \alpha_{yy}$ and $ \kappa_{yy}$ are significantly larger than $ \alpha_{xx}$ and $ \kappa_{xx}$ , respectively, due to the much larger squared Dirac velocity $ v_y^2$ compared to $ v_x^2$ .
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 11 figures
Physical Review B 112, 045406 (2025)
Stability of discrete-symmetry flocks: sandwich state, traveling domains and motility-induced pinning
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-14 20:00 EDT
Swarnajit Chatterjee, Mintu Karmakar, Matthieu Mangeat, Heiko Rieger, Raja Paul
Polar flocks in discrete active systems are often assumed to be robust, yet recent studies reveal their fragility under both imposed and spontaneous fluctuations. Here, we revisit the four-state active Potts model (APM) and show that its globally ordered phase is metastable across a broad swath of parameter space. Small counter-propagating droplets disrupt the flocking phase by inducing a persistent sandwich state, where the droplet-induced opposite-polarity lane remains embedded within the original flock, particularly pronounced at low noise, influenced by spatial anisotropy. In contrast, small transversely propagating droplets, when introduced into the flock, can trigger complete phase reversal due to their alignment orthogonal to the dominant flow and their enhanced persistence. At low diffusion and strong self-propulsion, such transverse droplets also emerge spontaneously, fragmenting the flock into multiple traveling domains and giving rise to a short-range order (SRO) regime. We further identify a motility-induced pinning (MIP) transition in small diffusion and low-temperature regimes when particles of opposite polarity interact, flip their state, hop, and pin an interface. Our comprehensive phase diagrams, encompassing full reversal, sandwich coexistence, stripe bands, SRO, and MIP, delineate how thermal fluctuations, self-propulsion strength, and diffusion govern flock stability in discrete active matter systems.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Unveiling the electronic structure of the charge density wave and topological semimetal TaTe4 through high-field magnetotransport measurements
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-14 20:00 EDT
D. Silvera-Vega, J. Rojas-Castillo, E. Herrera-Vasco, E. Ramos-Rodríguez, A. F. Santander-Syro, J. A. Galvis, B. Uribe, R. González-Hernández, A. C. García-Castro, P. Giraldo-Gallo
Understanding the interplay between topology and correlated electron states is central to the study of quantum materials. TaTe$ _4$ , a charge density wave (CDW) compound predicted to host topological phases, offers a platform to explore this interplay. Here, we report a comprehensive study of the Fermi surface (FS) of TaTe$ _4$ via high-field magnetotransport measurements and density functional theory (DFT) calculations. Using three distinct field-current configurations, we resolve four out of five FS pockets predicted in the CDW phase, with no evidence of residual non-CDW features - in contrast to recent ARPES studies. Remarkably, we identify a previously unobserved quasi-cylindrical hole pocket and a high-frequency quantum oscillation contribution to the magnetoresistance attributable to magnetic breakdown between reconstructed FS sheets, from which we estimate a CDW gap of $ \sim$ 0.29 eV. Additionally, we observe a robust linear magnetoresistance (MR) for all field orientations when current flows along the $ a-$ axis, with a distinct high-field linear MR regime emerging near the $ c-$ axis, consistent with FS hot spots and magnetic breakdown. Our results establish TaTe$ _4$ as a paradigmatic system where CDW-driven FS reconstruction governs the bulk electronic structure, enabling new routes to probe the novel physics that can arise in the intersection between correlated electronic states and topological band features.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
15 pages, 6 figures
Consciousness as a Jamming Phase
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-14 20:00 EDT
This paper develops a neural jamming phase diagram that interprets the emergence of consciousness in large language models as a critical phenomenon in high-dimensional disordered this http URL establishing analogies with jamming transitions in granular matter and other complex systems, we identify three fundamental control parameters governing the phase behavior of neural networks: temperature, volume fraction, and this http URL theory provides a unified physical explanation for empirical scaling laws in artificial intelligence, demonstrating how computational cooling, density optimization, and noise reduction collectively drive systems toward a critical jamming surface where generalized intelligence emerges. Remarkably, the same thermodynamic principles that describe conventional jamming transitions appear to underlie the emergence of consciousness in neural networks, evidenced by shared critical signatures including divergent correlation lengths and scaling this http URL work explains neural language models’ critical scaling through jamming physics, suggesting consciousness is a jamming phase that intrinsically connects knowledge components via long-range correlations.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Artificial Intelligence (cs.AI)
18 pages, 13 figures
Corner-Sharing PS$_4$-BS$_4$ Modes Facilitate Fast Ion Conduction in Lithium Thioborophosphate Iodide Glassy Solid Electrolytes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-14 20:00 EDT
Glassy solid electrolytes (GSEs), with their amorphous nature and the absence of grain boundaries, make them highly attractive for applications in all-solid-state lithium batteries (ASSLBs), a leading candidate for next-generation energy storage technologies. A recently developed lithium thioborophosphate iodide GSE, composed of 30Li$ _2$ S-25B$ _2$ S$ _3$ -45LiI-5P$ _2$ S$ _5$ (LBPSI), has demonstrated excellent room-temperature ionic conductivity and low activation energy. Despite this exciting finding, the underlying mechanism behind this ultrafast ion transport remains ambiguous. Here, we accurately fine-tune the foundational MACE-MP-0 model and perform large-scale machine learning molecular dynamics simulations to investigate the structural and ion dynamics in LBPSI GSE. Our results reveal that B$ _2$ S$ _3$ glass formers primarily form multi-bridged B$ _x$ S$ _y$ long-chain networks that impede Li$ ^+$ conduction. In contrast, P$ _2$ S$ _5$ gives rise to mono-tetrahedral PS$ _4$ ^{3-}$ and di-tetrahedral P$ _2$ S$ _7$ ^{4-}$ tetrahedra, which engage in distinctive corner-sharing modes with BS$ _4$ ^{5-}$ tetrahedra, effectively disrupting the B$ _x$ S$ _y$ chains and enhancing Li$ ^+$ mobility. Furthermore, the polyhedral anion rotations of PS$ _4$ ^{3-}$ and BS$ _4$ ^{5-}$ in the corner-sharing PS$ _4$ -BS$ _4$ motifs may further promote fast Li$ ^+$ conduction.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn)
Symmetry and Thermodynamic Bounds on Cross-Coupling Transport in Chiral Liquid Crystals
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-14 20:00 EDT
Shunsuke Takano, Takuya Nakanishi, Kenta Nakagawa, Toru Asahi
We reformulate the Leslie effects that describe the dynamic cross-couplings in chiral liquid crystals driven by the transport of heat, electric charge, and mass. The Ericksen–Leslie model is extended in the linear response framework by representing nematic order with the Q-tensor. Subsequently, the thermodynamic uncertainty relation is applied to identify the upper bounds of the Leslie cross-coupling coefficients. We reveal that the cross-coupling coefficients are dependent on the scalar order parameter and vanish in the isotropic phase. In addition, the chirality of the phase allows torque induced by a transport current parallel to the director. The mutual signs of the Leslie thermohydrodynamic and thermomechanical coefficients are likely to be opposite in calamitic liquid crystals, as suggested by recent experimental observations. Our model is applicable to the thermal, chemical, and electrical Leslie effects. The present arguments suggest that a common underlying principle may govern both the Leslie effects and the thermal Edelstein effect in chiral solid crystals attributed to chiral phonons.
Soft Condensed Matter (cond-mat.soft)
Thermoelectric optimization and quantum-to-classical crossover in gate-controlled two-dimensional semiconducting nanojunctions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
We investigate the thermoelectric performance of 2D nanojunctions with gate tunable architectures and varying channel lengths from 3 to 12 nm using a combination of first principles simulations, including density functional theory, DFT with nonequilibrium Greens function formalism (nanoDCAL), and nonequilibrium molecular dynamics simulations. Our study reveals a gate, temperature, and length dependent transition from quantum to classical in electron transport, transitioning from quantum tunneling in short junctions to thermionic emission in longer ones. We observe nontrivial dependencies of the thermoelectric figure of merit on the Seebeck coefficient, electrical conductivities, and thermal conductivities as a result of this crossover and gate controlling. We identify that maximizing ZT requires tuning the chemical potential just outside the band gap, where the system lies at the transition between insulating and conducting regimes. While extremely large Seebeck coefficients are observed in the insulating state, they do not yield high ZT due to suppressed electrical conductivity and dominant phononic thermal transport. The optimal ZT larger than 2.3 is achieved in the shortest 3 nm junction at 500 K, where quantum tunneling and thermionic emission coexist. These findings offer fundamental insights into transport mechanisms in 2D semiconducting nanojunctions and present design principles for high efficiency nanoscale thermoelectric devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 Figures
Validity of perturbation theory in calculations of magnetocrystalline anisotropy in Co-based layered systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
Validity of second-order perturbation theory (PT) is examined for magnetocrystalline anisotropy (MCA) energy in Co films with enhanced spin-orbit coupling (SOC) and Co/Pt bilayers. Comparison with accurate results obtained with the force theorem (FT) reveals significant discrepancies in the dependence of the MCA energy on the Co thickness. For systems with strong SOC, the PT fails to correctly describe the oscillations of the MCA energy, largely overestimating their amplitude and even failing (for Co/Pt bilayers) to reproduce their specific periodicity. These failures specifically concern the dominating oscillations with the 2-monolayer period which arise from pairs of quantum well (QW) minority-spin d states in the Co layer, degenerate at the centre of the Brillouin zone (BZ). A simplified model of such states demonstrates that the large discrepancies between PT and FT predictions arise from the breakdown of the PT in a region around the BZ centre where the energy spacing between states within each pair is small compared to the SOC strength. The oscillation amplitude of the MCA energy calculated with the FT is limited by the finite energy spacing between consecutive QW pairs, whereas this amplitude grows quadratically with the SOC strength in the PT calculations. Furthermore, for weak and moderate SOC strengths, the accuracy of the PT diminishes with increasing the ratio of the SOC constant to temperature. This explains why the PT overestimates the amplitude of MCA energy oscillations at low temperatures, even for the Co film with a relatively weak nominal SOC. For the Co/Pt bilayer, the strong temperature dependence of the oscillation amplitude in the PT approach leads to the MCA energies markedly different at low and zero temperatures, of opposite sign and several times larger in magnitude, compared to the FT results.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
24 pages, 26 figures
Symmetry-based theory of Dirac fermions on two-dimensional hyperbolic crystals: Coupling to the spin connection
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
Ana Djordjević, Marija Dimitrijević Ćirić, Vladimir Juričić
Discrete fermionic and bosonic models for hyperbolic lattices have attracted significant attention across a range of fields since the experimental realization of hyperbolic lattices in metamaterial platforms, sparking the development of hyperbolic crystallography. However, a fundamental and experimentally consequential aspect remains unaddressed: fermions propagating in curved space inherently couple to the underlying geometry via the spin connection, as required by general covariance - a feature not yet incorporated in studies of hyperbolic crystals. Here, we introduce a symmetry-based framework for Dirac fermions on two-dimensional hyperbolic lattices, explicitly incorporating spin-curvature coupling via a discrete spin connection. Starting from the continuous symmetries of the Poincaré disk, we classify the irreducible representations and construct a symmetry-adapted basis, establishing a direct correspondence to the continuum Dirac theory. We show that this continuum theory predicts a finite density of states at zero energy for any finite curvature in $ D-$ dimensional hyperbolic space with $ 2\leq D \leq 4$ , suggesting enhanced susceptibility of Dirac fermions to interaction-driven instabilities at weak coupling. We then derive explicit forms of discrete translational and rotational symmetries for lattices characterized by Schläfli symbols $ {p,q}$ , and explicitly construct the discrete spin connection, represented as hopping phases, via parallel transport. Our results pave the way for experimental realization of spin-curvature effects in metamaterial platforms and systematic numerical studies of correlated Dirac phases in hyperbolic geometries.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), General Relativity and Quantum Cosmology (gr-qc), High Energy Physics - Lattice (hep-lat), High Energy Physics - Theory (hep-th)
25 pages, 8 figures
Sensitive infrared surface photovoltage in quasi-equilibrium in a layered semiconductor at low-intensity low-temperature condition
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-14 20:00 EDT
Qiang Wan, Keming Zhao, Guohao Dong, Enting Li, Tianyu Yang, Hao Wang, Yaobo Huang, Yao Wen, Yiwei Li, Jun He, Youguo Shi, Hong Ding, Nan Xu
Benefit to layer-dependent bandgap, van der Waals materials with surface photovoltaic effect (SPV) enable photodetection over a tunable wavelength range with low power consumption. However, sensitive SPV in the infrared region, especially in a quasi-steady illumination condition, is still elusive in layered semiconductors. Here, using angle-resolved photoemission spectroscopy, we report a sensitive SPV in quasi-equilibrium in NbSi0.5Te2, with photoresponsivity up to 2.4\ast10^6 V/(W\astcm^(-2)) at low intensity low temperature condition (LILT). The sensitive SPV is further confirmed by observing the Dember effect, where the photogenerated carrier density is high enough and diffusion currents suppress SPV. Temperature-dependent measurements indicate that intrinsic carriers freezing at low temperature leads to the ultrahigh photoresponse, while a small amount of photon-generated carriers in quasi-equilibrium dominate the system. Our work not only provides a promising layered semiconductor for Infrared optoelectronic devices with strong infrared SPV at LILT, which has application potential in fields such as quantum information and deep-space exploration, but also paves a novel way to enhance light-matter interaction effect by freezing bulk carriers.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 4 figures
Anomalous diffusion in coupled viscoelastic media: A fractional Langevin equation approach
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-14 20:00 EDT
Anomalous diffusion often arises in complex environments where viscoelastic or crowded conditions influence particle motion. In many biological and soft-matter systems, distinct components of the medium exhibit unique viscoelastic responses, resulting in time-dependent changes in the observed diffusion exponents. Here, we develop a theoretical model of two particles, each embedded in a distinct viscoelastic medium, and coupled via a harmonic potential. By formulating and solving a system of coupled fractional Langevin equations (FLEs) with memory exponents $ 0<\alpha<\beta\leq 1$ , we uncover rich transient anomalous diffusion phenomena arising from the interplay of memory kernels and bilinear coupling. Notably, we identify recovery dynamics, where a subdiffusive particle ($ \alpha$ ) transiently accelerates and eventually regains its intrinsic long-time mobility. This recovery emerges only when memory exponents differ ($ \alpha<\beta$ ), whereas identical exponents ($ \alpha=\beta$ ) suppress recovery. Our theoretical predictions offer insight into experimentally observed transient anomalous diffusions, such as polymer–protein complexes and cross-linked cytoskeletal networks, highlighting the critical role of memory heterogeneity and mechanical interactions in biological anomalous diffusion.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph)
Rocksalt rare-earth monoxides as electronic and magnetic materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-14 20:00 EDT
Tomoteru Fukumura, Satoshi Sasaki, Masamichi Negishi, Daichi Oka
Stable binary rare earth (RE) oxides are usually trivalent RE ion sesquioxides (RE2O3), that are highly insulating and either nonmagnetic or antiferromagnetic. On the other hand, rocksalt-type divalent RE ion monoxides (REOs) have been scarcely synthesized owing to their metastable nature. Accordingly, their fundamental properties have not been unveiled. Recently, thin film epitaxy was successfully applied to synthesize various REOs. In stark contrast with RE2O3, REOs are highly electrically conducting, and exhibit superconductivity, room temperature ferromagnetism, and so on. Therefore, REOs are new and simple f-electron system, promising as electronic, magnetic, and spintronic materials. In this review, their fundamental properties are introduced, and their significance and future prospects are discussed toward a new paradigm in f-electron systems.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
22 pages, 5 figures
Trends in Chemistry 7, 384 (2025)
Quantized order parameters of approximate symmetry for metals and insulators
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-14 20:00 EDT
We develop a simple scheme to distinguish between metals and insulators, or more generally gapless and gapped phases, by introducing the notion of an approximate symmetry order parameter. For one dimensional systems, we provide an explicit proof for the known criteria of metals and insulators based on the polarization operator which have been widely accepted for decades without a rigorous proof. For higher dimensions, we introduce a tiny magnetic flux to control the system, where the translation symmetry becomes approximate. We show that insulators and metals can be well distinguished with use of the approximate symmetry operators and they work as quantized order parameters in the thermodynamic limit characterizing gapless and gapped nature of the system.
Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 5 figures
Control of nonreciprocal charge transport in topological insulator/superconductor heterostructures with Fermi level tuning and superconducting-layer thickness
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-14 20:00 EDT
Soma Nagahama, Yuki Sato, Minoru Kawamura, Ilya Belopolski, Ryutaro Yoshimi, Atsushi Tsukazaki, Naoya Kanazawa, Kei S Takahashi, Masashi Kawasaki, Yoshinori Tokura
Nonreciprocal charge transport (NCT) is defined as a phenomenon where electrical resistance depends on the current direction. It has been drawing much attention because it sensitively reflects the symmetry breaking of material systems. A topological insulator (TI)/superconductor (SC) heterostructure where the topological surface state (TSS) of the TI layer is proximitized with the SC layer is one such system that presents a sizable NCT due to a large spin-orbit coupling and superconductivity. Here, we report a control of the magnitude and sign of NCT: reversal of the direction of NCT by tuning the Fermi energy of TSS of the TI layer with respect to the charge neutral point by systematic regulation of Sb composition $ x$ in a TI/SC heterostructures of (Bi$ _{1-x}$ Sb$ _x$ )$ _2$ Te$ _3$ /FeSe$ _{0.1}$ Te$ _{0.9}$ . The result is consistent with the model of a TSS proximitized with superconductivity. Furthermore, we find a significant enhancement of the magnitude of NCT in the TI/SC heterostructures by reducing the thickness of the SC layer. The enhancement can be ascribed to the inversion-symmetry breaking of the FeSe$ _{0.1}$ Te$ _{0.9}$ SC-layer itself adjacent to the TI layer. Our results highlight the essential role of the TSS for exhibiting NCT and offer new knobs to control the direction and magnitude of NCT.
Superconductivity (cond-mat.supr-con)
24 pages, 4 figures, and supplemental material
Electronic and optical properties of the thio-apatites phases Ba$_5$(VS$_α$O$_β$)$_3$X [X=Cl, F, Br, I]: impact of multiple anionic substitution
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-14 20:00 EDT
A systematic study of the electronic structure and optical properties of the thio-apatites Ba$ _5$ (VS$ _{\alpha}$ O$ _{\beta}$ )$ _3$ X (X= Cl, F, Br, I) is carried out through first principles density functional theory simulations. The band gap and properties evolution from fluorine to iodine on fixed O/S ratios, as well as by substituting sulfur (S) for oxygen (O) are discussed. The reduction of the band gap by raising valence band energy levels, with an increasing S/O ratio can also be further modulated by the type of halide in the channels of the structure, thus promoting fine tuning of the band gap region. Defect states also play a crucial role in band gap modulation. Furthermore, the examination of the band edges properties in Ba$ _5$ (VS$ _{\alpha}$ O$ _{\beta}$ )$ _3$ X compounds suggests they can be potential photocatalysts candidates for the water splitting reaction, with reduced band gaps enabling efficient light-driven reactions, particularly in Ba$ _5$ (VS$ _{\alpha}$ O$ _{\beta}$ )$ _3$ I. Optical investigations reveal that sulfur doping induces optical anisotropy, enhancing light absorption and offering tailored optical behaviour. These results provide new insights for the design of functional materials in the broad family of apatites.
Materials Science (cond-mat.mtrl-sci)
Nanoscale symmetry protection of the reciprocal acoustoelectric effect
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-14 20:00 EDT
Sandeep Vijayan, Stephan Suffit, Scott E. Cooper, Yejun Feng
Neumann’s principle states that all physical properties of a material are bound by its symmetry. While bulk crystals follow well-defined point and space groups, phenomena at a substrate’s surface could have less apparent symmetry origins. Here we experimentally explore both reciprocal and non-reciprocal types of acoustoelectric (AE) effects driven by surface acoustic waves (SAW). The non-reciprocal AE voltage is connected to the natural single-phase unidirectional transducer from device engineering. On the other hand, reciprocal AE effect exists in certain SAW configurations that are of different symmetry origins. Half of the configurations have a valid reciprocity-preserving symmetry element of either a mirror plane or an even-order rotational axis that is perpendicular to the substrate surface. The other half of the configurations do not possess reciprocity-preserving symmetry operations of the half-space but have the SAW propagation and the surface normal directions interchanged from the first scenario. Here, the reciprocity of SAW states is protected by the symmetric structure of the nanoscale strain tensor. The correspondence between two types of configurations has its origin imbedded in the SAW composition of both compression and shear waves along two orthogonal directions respectively.
Materials Science (cond-mat.mtrl-sci)
Interfacially ordered phase states enable high-strength ductile eutectic Al alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-14 20:00 EDT
Hemant Kumar, Praveen Kumar, Dierk Raabe, Baptiste Gault, Surendra Kumar Makineni
Lightweight, high-strength structural materials are component enablers in transportation and aerospace, improving carbon footprint and fuel efficiency. Aluminium (Al)-based eutectics have property combinations that qualify them for such applications. However, they are prone to catastrophic failure because of insufficient load transfer across the interfaces between the brittle eutectic phase and the ductile matrix. Here we present a general solution to this problem by engineering these interfaces at the atomic scale, equipping them with excellent load transfer capabilities, thus qualifying such composites for lightweight structural applications. We demonstrate the approach by adding Zr to an Al-Gd-based hypoeutectic alloy, promoting the formation of a coherent Interfacial-Ordered-Phase (IOP) around the brittle Al3Gd eutectic phase and nanosized core-shell ordered precipitates in the primary Al matrix. This enables a 400% increase in tensile plasticity while retaining a high tensile strength of 295 MPa at room temperature and 130 MPa at 250C. This exceptional increase in formability is attributed to the ability of the IOP layer to prevent dislocations from accumulating at the weak fibre/matrix interfaces, avoiding stress concentrations that would otherwise initiate fibre breakage and debonding. The core-shell precipitates in Al cause a large number of dislocation cross/multiple-slips on different {111} planes, forming ultra-fine (10 nm) dislocation networks that leverage substantial plastic strain accumulation. The approach shows how atomic interface design overcomes the ductility limitations of lightweight high-strength ductile eutectic alloys for structural applications.
Materials Science (cond-mat.mtrl-sci)
Dynamic scaling of growing interfaces
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-14 20:00 EDT
We give a brief overview of the seminal paper which introduced the Kardar-Parisi-Zhang equation as a paradigmatic model for random growth in 1986. We describe some of the developments to which it gave rise in mathematics and physics over the years, and some examples of applications.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Mathematical Physics (math-ph), Probability (math.PR), Cellular Automata and Lattice Gases (nlin.CG), Exactly Solvable and Integrable Systems (nlin.SI)
“Chapter of the book “From Quantum Fields to Spin Glasses - Seminal contributions of Giorgio Parisi to theoretical physics”, Cambridge University Press , to appear”, 25 pages, 6 figures
Enhanced dispersion of active microswimmers in confined flows
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-14 20:00 EDT
Marc Lagoin (LOMA), Juliette Lacherez (LOMA), Guirec de Tournemire (LOMA), Ahmad Badr (LOMA), Yacine Amarouchene (LOMA), Antoine Allard (LOMA, UB), Thomas Salez (LOMA)
In the presence of a laminar shear flow, the diffusion of passive colloidal particles is enhanced in the direction parallel to the flow. This classical phenomenon is known as Taylor-Aris dispersion. Besides, microorganisms, such as active microswimmers, exhibit an effective diffusive behavior at long times. Combining the two ingredients above, a natural question then emerges on how the effective diffusion of active microswimmers is altered in shear flows - a widespread situation in natural environments with practical implications, e.g. regarding biofilm formation. In this Letter, we investigate the motility and dispersion of Chlamydomonas reinhardtii microalgae, within a rectangular microfluidic channel subjected to a sinusoidal Poiseuille flow. Using high-resolution optical microscopy and a particle-tracking algorithm, we reconstruct individual trajectories in various flow conditions and statistically analyze them through moment theory and wavelet decomposition. We find that the velocity fluctuations and the dispersion coefficient increase as the flow amplitude is increased, with only weak dependencies on the flow periodicity. Importantly, our results demonstrate that the generalization of Taylor-Aris law to active particles is valid.
Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph), Classical Physics (physics.class-ph)
The effects of knot topology on the collapse of active polymers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-14 20:00 EDT
Davide Breoni, Emanuele Locatelli, Luca Tubiana
We use numerical simulations to study tangentially active flexible ring polymers with different knot topologies. Simple, unknotted active rings display a collapse transition upon increasing the degree of polymerization. We find that topology has a significant effect on the polymer size at which the collapse takes place, with twist knots collapsing earlier than torus knots. Increasing knot complexity further accentuates this difference, as the collapse point of torus knots grows linearly and that of twist knots shrinks, eventually canceling the actively stretched regime altogether. This behavior is a consequence of the ordered configuration of torus knots in their stretched active state, featuring an effective alignment for non-neighboring bonds which increases with the minimal crossing number. Twist knots do not feature ordered configurations or bond alignment, increasing the likelihood of collisions, leading to collapse. These results yield a degree of control on the collapse point of active ring polymers, as it can be tuned by changing the topology.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
28 pages, 11 figures
Learning the bulk and interfacial physics of liquid-liquid phase separation
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-14 20:00 EDT
Silas Robitschko, Florian Sammüller, Matthias Schmidt, Robert Evans
We use simulation-based supervised machine learning and classical density functional theory to investigate bulk and interfacial phenomena associated with phase coexistence in binary mixtures. For a prototypical symmetrical Lennard-Jones mixture our trained neural density functional yields accurate liquid-liquid and liquid-vapour binodals together with predictions for the variation of the associated interfacial tensions across the entire fluid phase diagram. From the latter we determine the contact angles at fluid-fluid interfaces along the line of triple-phase coexistence and confirm there can be no wetting transition in this symmetrical mixture.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
7 pages, 4 figures
Strengthened correlations near [110] edges of $d$-wave superconductors in the t-J model with the Gutzwiller approximation
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-14 20:00 EDT
Ambjorn Joki, Mikael Fogelstrom, Tomas Lofwander
We report results of a study of strongly correlated $ d$ -wave superconducting slabs within a t-J model solved using the statistically consistent Gutzwiller approach. For different dopings, we model slabs cut at 45$ ^\circ$ relative to the main crystallographic $ ab$ -axes, i.e., [110] orientation, and conclude that quasiparticle charge is drawn to the edges. Thus, the correlations are locally strengthened, and a region near the edge is closer to the Mott insulating state with reduced hopping amplitudes on the links. Superconductivity is locally weakened near the edges in the correlated state, and the spectral weight of zero-energy Andreev bound states is substantially reduced compared to weak coupling theory. The renormalization of the edge states leaves no room for an extended $ s$ -wave component to form for hole dopings ranging from strongly underdoped to slightly overdoped.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 8 figures
Thermodynamic theory of square skyrmion lattice in tetragonal frustrated antiferromagnets
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-14 20:00 EDT
Oleg I. Utesov, Danila P. Budylev
High-temperature part of the phase diagram of tetragonal frustrated antiferromagnets is discussed within the framework of the mean-field approach. Based on recent experimental and theoretical studies, we consider a model including frustrated Heisenberg exchange, biquadratic exchange, anisotropic exchange, and magnetodipolar interaction. It is analytically demonstrated that a subtle interplay among these interactions results in a variety of phase diagrams in the temperature-magnetic field plane. We argue that the phase diagram obtained for the easy axis along the high-symmetry direction $ [001]$ and moderate biquadratic exchange reproduces all crucial features of the phase diagram experimentally observed for\gdrucompound. The topological properties of the respective double-modulated square skyrmion lattice phase are discussed. The developed analytical approach can also be useful for the refinement of the microscopic model parameters when comparing its predictions with experimental findings.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
16 pages, 7 figures
Observation of quasi-steady dark excitons and gap phase in a doped semiconductor
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-14 20:00 EDT
Shangkun Mo, Yunfei Bai, Chunlong Wu, Xingxia Cui, Guangqiang Mei, Qiang Wan, Renzhe Li, Cao Peng, Keming Zhao, Dingkun Qin, Shuming Yu, Hao Zhong, Xingzhe Wang, Enting Li, Yiwei Li, Limin Cao, Min Feng, Sheng Meng, Nan Xu
Exciton plays an important role in optics and optics-related behaviors and leads to novel correlated phases like charge order, exciton insulator, and exciton-polariton condensation. Dark exciton shows distinct properties from bright one. However, it cannot be directly detected by conventional optic measurements. The electronic modulation effect of dark excitons in quasi-equilibrium distribution, critical for electronic devices in working status, is still elusive. Here, using angle-resolved photoemission spectroscopy, we report creating, detecting, and controlling dark excitons in the quasi-equilibrium distribution in a doped semiconductor SnSe2. Surprisingly, we observe an excitonic gap phase, with a conduction band opening an anisotropic gap. Our results broaden the scope of dark excitons, extending their studies from the picosecond timescale in the ultrafast photoemission process to conditions occurring under quasi-equilibrium. We reveal the light-matter interaction in the engineering of electronic structures and provide a new way to realize the excitonic gap phase in semiconductors with large band gaps.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
16 pages, 5 figures
A Cryogenic Uniaxial Strain Cell for Elastoresistance Measurements
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-14 20:00 EDT
Eckelt Franz, Cavallaro Isidoro, Wagner Ralph, Haghighirad Amir-Abbas, Wolf Thomas, Wilmers Jana, Bargmann Swantje, Hess Christian
We present the design, implementation, and validation of a cryo-compatible strain cell for elastoresistance measurements in quantum materials. The cell is actuated by three large-format piezoelectric stacks and enables both compressive and tensile strain up to approximately $ \pm5%$ . The relative displacement of the sample holders is measured in situ using a high-resolution capacitive displacement sensor, ensuring precise strain control throughout measurement. To operate the strain cell over a broad temperature range from 4.2,K to 300,K, a modular measurement probe was developed, allowing efficient thermal coupling and integration into cryogenic environments. The functionality and precision of the setup were demonstrated by elastoresistance measurements on the iron-based superconductor BaFe$ _2$ As$ _2$ along the [110] direction. The results were validated against conventional techniques based on glued samples and strain gauges, showing excellent agreement in amplitude and temperature dependence of the elastoresistance coefficient. Additional tests revealed that the system remains robust under mechanical vibrations introduced by vacuum pumps, enabling stable operation even with liquid nitrogen cooling. This highlights the high mechanical and thermal reliability of the developed platform for low-temperature transport measurements under controlled uniaxial strain.
Superconductivity (cond-mat.supr-con), Instrumentation and Detectors (physics.ins-det)
Extending Nonlocal Kinetic Energy Density Functionals to Isolated Systems via a Density-Functional-Dependent Kernel
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-14 20:00 EDT
The Wang-Teter-like nonlocal kinetic energy density functional (KEDF) in the framework of orbital-free density functional theory, while successful in some bulk systems, exhibits a critical Blanc-Cances instability [J. Chem. Phys. 122, 214106 (2005)] when applied to isolated systems, where the total energy becomes unbounded from below. We trace this instability to the use of an ill-defined average charge density, which causes the functional to simultaneously violate the scaling law and the positivity of the Pauli energy. By rigorously constructing a density-functional-dependent kernel, we resolve these pathologies while preserving the formal exactness of the original framework. By systematically benchmarking single-atom systems of 56 elements, we find the resulting KEDF retains computational efficiency while achieving an order-of-magnitude accuracy enhancement over the WT KEDF. In addition, the new KEDF preserves WT’s superior accuracy in bulk metals, outperforming the semilocal functionals in both regimes.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
5 pages, 4 figures
Nonconserved critical dynamics of the two-dimensional Ising model as a surface kinetic roughening process
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-14 20:00 EDT
Hector Vaquero del Pino, Rodolfo Cuerno
We have revisited the non-conserved (or model A) critical dynamics of the two-dimensional Ising model through numerical simulations of its lattice and continuum formulations –Glauber dynamics and the timedependent Ginzburg-Landau (TDGL) equation, respectively–, to analyze them with current tools from surface kinetic roughening. Our study examines two critical quenches, one from an ordered and a different one from a disordered initial state, for both of which we assess the dynamic scaling ansatz, the critical exponent values, and the fluctuation field statistics that occur. Notably, the dynamic scaling ansatz followed by the system strongly depends on the initial condition: a critical quench from the ordered phase follows Family-Vicsek (FV) scaling, while a critical quench from the disordered phase shows an initial overgrowth regime with intrinsic anomalous roughening, followed by relaxation to equilibrium. This behavior is explained in terms of the dynamical instability of the stochastic Ginzburg-Landau equation at the critical temperature, whereby the linearly unstable term is eventually stabilized by nonlinear interactions. For both quenches we have determined the occurrence of probability distribution functions for the field fluctuations, which are time-independent along the non-equilibrium dynamics when suitably normalized by the time-dependent fluctuation amplitude. Additionally, we have developed a related interface model for a field which scales as the space integral of the TDGL field (integral GL model). Numerical simulations of this model reveal either FV or faceted anomalous roughening, depending on the critical quenched performed, as well as an emergent symmetry in the fluctuation statistics for a critical quench from the ordered phase.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Adaptation and Self-Organizing Systems (nlin.AO), Computational Physics (physics.comp-ph)
28 pages, 32 figures, submitted
Modulation of energy and angular momentum radiation of two-dimensional altermagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
This paper investigates the energy and angular momentum radiation of altermagnets under Rashba spin-orbit coupling (RSOC) and external magnetic fields. Using an effective low-energy Hamiltonian, we derive electronic energy bands and calculate optical conductivity via the Kubo formula. Results show that RSOC strength, altermagnet interactions strength, and Neel vector direction notably affect the optical conductivity of altermagnet metals. Energy radiation is highly sensitive to Rashba spin-orbit coupling, with a saturation effect beyond a particular value, and its peak emission rate is lower than that of graphene due to reduced conductivity. Different from usual semi-conductor, semi-metal or Dirac materials, eg. graphene or silicene, altermagnets generate angular momentum radiation with specific Rashba spin-orbit coupling and altermagnet interaction strength. Angular momentum radiation is minimally reactive to Rashba spin-orbit coupling at low altermagnet interactions strength values but exhibits drastic oscillations between extreme values as altermagnet interactions strength reaches a critical point, showing high sensitivity. These findings suggest that adjusting these parameters can tailor altermagnet applications in spintronics and quantum technologies, potentially leading to innovative devices with customized radiation attributes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
11 pages, 14 figures
Coarse Graining Photo-Isomerization Reactions: Thermodynamic Consistency and Implications for Molecular Ratchets
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-14 20:00 EDT
Francesco Avanzini, Massimiliano Esposito, Emanuele Penocchio
We formulate thermodynamically consistent coarse-graining procedures for molecular systems undergoing thermally and photo-induced transitions: starting from elementary vibronic transitions, we derive effective photo-isomerization reactions interconverting ground-state species. Crucially, the local detailed balance condition, that constrains reaction kinetics to thermodynamics, remains satisfied throughout the coarse-graining procedures. It applies to the effective photo-isomerization reactions just as it does to the elementary vibronic transitions. We then demonstrate that autonomous photo-driven molecular ratchets operate via the same fundamental mechanism as chemically driven ones. Because the local detailed balance remains satisfied, autonomous photo-driven molecular ratchets, like chemically driven ones, operate exclusively through an information ratchet mechanism. This reveals new key principles for their design and optimization.
Statistical Mechanics (cond-mat.stat-mech), Chemical Physics (physics.chem-ph)
Virtual walks in the Ising model: a different criticality in two dimensions?
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-14 20:00 EDT
Amit Pradhan, Parongama Sen, Sagnik Seth
The dynamics of the spins in the Ising model are analysed using a virtual walk scenario. The system is quenched from a very high temperature to a lower one using the Glauber scheme. A walk is associated with each spin which evolves according to the current state of the spin. The known critical temperatures can be accurately detected in both one and two dimensions using the properties of the distribution of the displacements of the walkers. In one dimension, exponentially diverging quantities are obtained close to zero temperature. In two dimensions, a second type of walk involving local energies is considered and several quantities are found to exhibit power law behavior near the critical point. The results in two dimensions suggest an unconventional phase transition occurring in terms of the walk dynamics at the known critical temperature.
Statistical Mechanics (cond-mat.stat-mech)
8 pages, 11 figures
The viscoelastic rheology of transient diffusion creep
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-14 20:00 EDT
Polycrystalline materials have a viscoelastic rheology where the strains produced by stresses depend on the timescale of deformation. Energy can be stored elastically within grain interiors and dissipated by a variety of different mechanisms. One such dissipation mechanism is diffusionally-accommodated/-assisted grain boundary sliding, also known as transient diffusion creep. Here we detail a simple reference model of transient diffusion creep, based on finite element calculations with simple grain shapes: a regular hexagon in 2D and a tetrakaidecadedron in 3D. The linear viscoelastic behaviour of the finite element models can be well described by a parameterised extended Burgers model, which behaves as a Maxwell model at low frequencies and as an Andrade model at high frequencies. The parametrisation has a specific relaxation strength, Andrade exponent and Andrade time. The Andrade exponent depends only on the angles at which grains meet at triple junctions, and can be related to the exponents of stress singularities that occur at triple junctions in purely elastic models without diffusion. A comparison with laboratory experiments shows that the simple models here provide a lower bound on the observed attenuation. However, there are also clearly additional dissipative processes occurring in laboratory experiments that are not described by these simple models.
Materials Science (cond-mat.mtrl-sci), Geophysics (physics.geo-ph)
34 pages, 9 figures
Quantum register based on double quantum dots in semiconductor nanowires
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
Vladimir Vyurkov, Leonid Fedichkin, Igor Semenikhin, Denis Drozhzhin, Konstantin Rudenko, Vladimir Lukichev
An implementation of a universal solid-state quantum register based on electron space states in field-defined double quantum dots (DQD possesses one electron in two adjacent tunnel bound dots) in an ultrathin semiconductor nanowire is discussed. To some extent, the structure resembles that of a field-effect transistor with multiple controlling electrodes (gates). Scalability is audible and it opens up a possibility of large-scale quantum computer fabricated by advanced silicon technology. Moreover, the structure could be developed into an ensemble quantum register where instead of single nanowire an array of them with common controlling electrodes and contacts is fabricated. This ensemble register is much more resistant against environment noise caused by phonons and stray charges due to averaging and compensation. It is crucial that an individual qubit consists of two DQDs. The basic states of that qubit correspond to symmetric state of one DQD and antisymmetric state of another, and vice versa. Then the quantum information can be encoded and processed without charge transfer between dots. The probability to find an electron in a dot constantly equals 1/2 thus the Coulomb interaction between DQDs is also constant. Although the Coulomb interaction is incessant, the strength of its action depends on mutual states of interacting DQDs (in-resonance or off-resonance). Therefore, a quantum algorithm could be effectuated via manipulation solely with steady and pulse gate potentials that reminds an operation of a digital integrated circuit. The final read-out of the register is performed after decoding into charge states of DQDs and a transmission of current through the wire.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
9 pages, 8 figures
Hydrogen toggling between Yoshimori spin spirals and elliptical Dzyaloshinskii-Moriya skyrmions in Fe on Ir(110)
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
Timo Knispel, Vasily Tseplyaev, Gustav Bihlmayer, Stefan Blügel, Thomas Michely, Jeison Fischer
Skyrmions are particle-like spin textures that arise from spin spiral states in the presence of an external magnetic field. These spirals can originate from either frustrated Heisenberg exchange interactions or the interplay between exchange interactions and the relativistic Dzyaloshinskii-Moriya interaction, leading to atomic- and mesoscale textures, respectively. However, the conversion of exchange-stabilized spin spirals into skyrmions typically requires magnetic fields that exceed practical laboratory limits. Here, we demonstrate a strategy leveraging hydrogen adsorption to expand the range of magnetic films capable of hosting stable or metastable skyrmions. In a structurally open and anisotropic system of two pseudomorphic Fe layers on Ir(110), spin-polarized scanning tunneling microscopy combined with ab initio calculations reveals that a right-handed, exchange-stabilized Néel-type spin spiral propagating along the [$ \overline{1}10$ ] direction with a $ 1.3$ ~nm period transitions upon hydrogen adsorption to a Dzyaloshinskii-Moriya type spiral with a sevenfold longer period of $ 8.5$ ~nm. This transition enables elliptical skyrmions to form at moderate magnetic fields. Hydrogenation thus provides a non-volatile mechanism to toggle between distinct magnetic states, offering a versatile platform for controlling spin textures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Phase analysis of Ising machines and their implications on optimization
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-14 20:00 EDT
Shu Zhou, K. Y. Michael Wong, Juntao Wang, David Shui Wing Hui, Daniel Ebler, Jie Sun
Ising machines, which are dynamical systems designed to operate in a parallel and iterative manner, have emerged as a new paradigm for solving combinatorial optimization problems. Despite computational advantages, the quality of solutions depends heavily on the form of dynamics and tuning of parameters, which are in general set heuristically due to the lack of systematic insights. Here, we focus on optimal Ising machine design by analyzing phase diagrams of spin distributions in the Sherrington-Kirkpatrick model. We find that that the ground state can be achieved in the phase where the spin distribution becomes binary, and optimal solutions are produced where the binary phase and gapless phase coexist. Our analysis shows that such coexistence phase region can be expanded by carefully placing a digitization operation, giving rise to a family of superior Ising machines, as illustrated by the proposed algorithm digCIM.
Statistical Mechanics (cond-mat.stat-mech), Data Analysis, Statistics and Probability (physics.data-an)
5 pages, 4 figures
Emergent Softening and Stiffening Dictate Transport of Active Filaments
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-14 20:00 EDT
Bipul Biswas, Prasanna More, Hima Nagamanasa Kandula
Active semiflexible filaments are crucial in various biophysical processes, yet insights into their single-filament behavior have predominantly relied on theory and simulations, owing to the scarcity of controllable synthetic systems. Here, we present an experimental platform of active semiflexible filaments composed of dielectric colloidal particles, activated by an alternating electric field that induces contractile or extensile electrohydrodynamic (EHD) flows. Our experiments reveal that contractile flow generating filaments undergo softening, significantly expanding the range of accessible conformations, whereas filaments composed of extensile flow monomers exhibit active stiffening. By independently tuning filament elasticity and activity, we demonstrate that the competition between elastic restoring forces and emergent hydrodynamic interactions along the filament governs conformational dynamics. Crucially, we discover that the timescale of conformational dynamics directly governs transport behavior: enhanced fluctuations promote diffusion while stiffening facilitates directed propulsion of nonlinear filaments. Together, our direct visualization studies elucidate the links between inherent filament properties, microscopic activity, and emergent transport while establishing a versatile experimental platform of synthetic filamentous active matter.
Soft Condensed Matter (cond-mat.soft), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Abinit 2025: New Capabilities for the Predictive Modeling of Solids and Nanomaterials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-14 20:00 EDT
Matthieu J. Verstraete, Joao Abreu, Guillaume E. Allemand, Bernard Amadon, Gabriel Antonius, Maryam Azizi, Lucas Baguet, Clementine Barat, Louis Bastogne, Romuald Bejaud, Jean-Michel Beuken, Jordan Bieder, Augustin Blanchet, Francois Bottin, Johann Bouchet, Julien Bouquiaux, Eric Bousquet, James Boust, Fabien Brieuc, Veronique Brousseau-Couture, Nils Brouwer Fabien Bruneval, Alois Castellano, Emmanuel Castiel, Jean-Baptiste Charraud, Jean Clerouin, Michel Cote, Clement Duval, Alejandro Gallo, Frederic Gendron, Gregory Geneste, Philippe Ghosez, Matteo Giantomassi, Olivier Gingras, Fernando Gomez-Ortiz, Xavier Gonze, Felix Antoine Goudreault, Andreas Gruneis, Raveena Gupta, Bogdan Guster, Donald R. Hamann, Xu He, Olle Hellman, Natalie Holzwarth, Francois Jollet, Pierre Kestener, Ioanna-Maria Lygatsika, Olivier Nadeau, Lorien MacEnulty, Enrico Marazzi, Maxime Mignolet, David D. O’Regan, Robinson Outerovitch, Charles Paillard, Guido Petretto, Samuel Ponce, Francesco Ricci, Gian-Marco Rignanese, Mauricio Rodriguez-Mayorga, Aldo H. Romero, Samare Rostami, Miquel Royo, Marc Sarraute, Alireza Sasani, Francois Soubiran, Massimiliano Stengel, Christian Tantardini, Marc Torrent, Victor Trinquet, Vasilii Vasilchencko, David Waroquiers, Asier Zabalo, Austin Zadoks, Huazhang Zhang, Josef Zwanziger
Abinit is a widely used scientific software package implementing density functional theory and many related functionalities for excited states and response properties. This paper presents the novel features and capabilities, both technical and scientific, which have been implemented over the past 5 years. This evolution occurred in the context of evolving hardware platforms, high-throughput calculation campaigns, and the growing use of machine learning to predict properties based on databases of first principles results. We present new methodologies for ground states with constrained charge, spin or temperature; for density functional perturbation theory extensions to flexoelectricity and polarons; and for excited states in many-body frameworks including GW, dynamical mean field theory, and coupled cluster. Technical advances have extended abinit high-performance execution to graphical processing units and intensive parallelism. Second principles methods build effective models on top of first principles results to scale up in length and time scales. Finally, workflows have been developed in different community frameworks to automate \abinit calculations and enable users to simulate hundreds or thousands of materials in controlled and reproducible conditions.
Materials Science (cond-mat.mtrl-sci)
Band Meandering due to Charged Impurity Effects and Carrier Transport in Ternary Topological Insulators
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-14 20:00 EDT
Kanav Sharma, Niranjay K R, Radha Krishna Gopal, Chiranjib Mitra
In this study, we investigated the impact of charged impurities on the electrical properties of the topological insulator $ \left(\mathrm{Bi}{0.3} \mathrm{Sb}{0.7}\right)2 \mathrm{Te}3$ (BST) and its indium-doped counterpart, $ \mathrm{In}{0.14}\left(\mathrm{Bi}{0.3} \mathrm{Sb}{0.7}\right){1.86} \mathrm{Te}3$ (IBST), using field-effect gating. For thin BST (30 nm), charged impurities, potentially from silicon dioxide substrate traps, contribute to band tail-type localization, with the impurity density ($ n{\text{imp}} = 10^{11} \text{ cm}^{-2} $ ) suggesting an external influence, though quantitative confirmation is needed. In contrast, thick BST (60 nm) exhibits potential fluctuations driven by inherent impurities ($ n_{\text{imp}} = 2.23 \times 10^{14} \text{ cm}^{-2} $ ), forming electron-rich (n-type) and hole-rich (p-type) regions that cause band meandering near the chemical potential. Indium doping in thin IBST significantly increases the impurity density to $ 1.53 \times 10^{15} \text{ cm}^{-2} $ , exacerbating these fluctuations and reducing mobility due to enhanced scattering. Gate-dependence analysis further revealed a temperature-driven transition from n-type to p-type characteristics at elevated temperatures (~170 K), attributed to thermal activation of holes in p-type regions. These findings highlight the critical role of impurity management in optimizing topological insulators for applications in spintronics and quantum computing.
Materials Science (cond-mat.mtrl-sci)
Local persistence exponent and its log-periodic oscillations
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-14 20:00 EDT
We investigate the local persistence exponent of the survival probability of a particle diffusing near an absorbing self-similar boundary. We show by extensive Monte Carlo simulations that the local persistence exponent exhibits log-periodic oscillations over a broad range of timescales. We determine the period and mean value of these oscillations in a family of Koch snowflakes of different fractal dimensions. The effect of the starting point and its local environment on this behavior is analyzed in depth by a simple yet intuitive model. This analysis uncovers how spatial self-similarity of the boundary affects the diffusive dynamics and its temporal characteristics in complex systems.
Statistical Mechanics (cond-mat.stat-mech), Chemical Physics (physics.chem-ph)
Chiral-split magnons in the S = 1 Shastry-Sutherland model
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
In ferromagnets, magnons have only one chirality; while in common antiferromagnets, bands with opposite chiralities are degenerate across the Brillouin zone. Recent studies have shown that it is possible to observe non-degenerate bands of opposite chiralities in altermagnetic materials. Here we take the S = 1 Shastry-Sutherland model, which shows the collinear Néel (I) phase, and investigate the magnon band structure showing alternate chirality-splitting and the resulting transport properties. In magnon bands, we find a notable feature of the chirality-split magnon bands, and the split is opposite along two different directions in the Brillouin zone. We also calculate the spin and thermal conductivities using Kubo formalism. Our calculations show robust spin Seebeck and spin Nernst effects due to the alternating chirality split across the Brillouin zone, without any external magnetic field and spin-orbit coupling.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5 pages, 3 figures
Granular jamming and rheology in microgravity
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-14 20:00 EDT
Qing Yu, Thorsten Pöschel, Olfa D’Angelo
Understanding how granular materials behave in low gravity is crucial for planetary science and space exploration. It can also help us understand granular phenomena usually hidden by gravity. On Earth, gravity dominates granular behavior, but disentangling its role from intrinsic particle interactions is challenging. We present a series of compression and shear experiments conducted in microgravity using the Center of Applied Space Technology and Microgravity (ZARM) drop tower and GraviTower Bremen (GTB). Our in-house developed experimental setup enables precise measurement of packing density and in-situ shear stress via a Taylor-Couette rheometer. We find that the jamming transition occurs at lower packing density in microgravity than on Earth, confirming that gravity promotes densification. Rheological measurements further reveal that in microgravity, the lack of a secondary force field and predominance of cohesive interparticle forces increase the stress needed for granular media to flow. These findings highlight gravity’s dual role in enhancing both compaction and flow, and demonstrate the need for tailored granular models, valid in low- and microgravity environments.
Soft Condensed Matter (cond-mat.soft), Space Physics (physics.space-ph)
Microscopic Scattering Approach to In-Gap States: Cr Adatoms on Superconducting β-Bi2Pd
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-14 20:00 EDT
Joseph Sink, Hari Paudyal, Divya Jyoti, Andreas J. Heinrich, Deung-Jang Choi, Nicolás Lorente, Michael E. Flatté
We develop a microscopic scattering formalism to describe Yu-Shiba-Rusinov (YSR) states due to a single Cr adatom on the Bi-terminated surface of $ \beta-Bi_2Pd$ , by combining ab initio Wannier functions with a real-space Green’s function approach in the Bogoliubov-de Gennes formalism. Our framework reproduces key scanning tunneling spectroscopy features, including a single particle-hole asymmetric YSR peak and isotropic dIdV maps around the impurity. Decomposing the YSR states reveals contributions from four nearly degenerate C4v representations, with energy broadening masking their individual signatures. Spin-orbit coupling induces partial spin polarization, while the spatial asymmetry between particle and hole components arises from Cr d-Bi p hybridization. These results highlight the importance of realistic band structures and microscopic modeling for interpreting STM data and provide a foundation for studying impurity chains hosting topological excitations.
Superconductivity (cond-mat.supr-con)
Screened superexchange mechanism for superconductivity applied to cuprates
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-14 20:00 EDT
In 1965, Kohn and Luttinger published a note revealing that dynamical screening of the repulsive Coulomb interaction leads under certain conditions to an effective attraction necessary for the formation of Cooper pairs. We propose such a formalism adapted to the cuprates where the screening arises from the superexchange dynamics of virtual holes in the oxygen orbitals of the $ Cu O_2$ plane. Using an adequate Schrieffer-Wolff transformation, the basic Hartree-Fock-Bogoliubov (HFB) method and the {\it ab initio} data on orbitals (energy, hopping, interaction), we derive some predictions for the temperature-doping phase diagram (pseudo-gap, strange metal, antiferromagnetism, superconducting and normal states) and for the doping dependant band energy spectrum in semi-quantitative agreement with observations.
Superconductivity (cond-mat.supr-con)
14 pages, 4 figures
Interplay of polar order and positional order in liquid crystals – observation of re-entrant ferroelectric nematic phase
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-14 20:00 EDT
Grant Strachan, Shona Ramsay, Marijus Juodka, Damian Pociecha, Jadwiga Szydlowska, John M.D. Storey, Natasa Vaupotic, Rebecca Walker, Ewa Gorecka
We show that development of polar order may spontaneously destroy the lamellar structure of a liquid crystal. This results in an unusual sequence of phases with the ferroelectric nematic phase appearing below a non-polar smectic phase. The effect is related to unfavourable dipole interactions within the smectic layers and can be explained by Landau theory in which the temperature dependent term is non-monotonic as it is renormalized by spontaneous electric polarization.
Soft Condensed Matter (cond-mat.soft)
Suppression of Intertwined Density Waves in La$4$Ni${3-x}$Cu$x$O${10+δ}$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-14 20:00 EDT
Stephen Zhang, Danrui Ni, Ruyi Ke, Guangming Cheng, Nan Yao, Robert J. Cava
Superconductivity in La$ _{4}$ Ni$ _{3}$ O$ _{10}$ has been reported to emerge upon suppression of intertwined spin and charge density wave (SDW/CDW) order, suggesting a possible connection to the pairing mechanism. Here we report a systematic investigation of La$ _{4}$ Ni$ _{3-x}$ Cu$ _{x}$ O$ _{10+\delta}$ ($ 0 \leq x \leq 0.7$ ), focusing on the evolution of the SDW/CDW order as a function of chemical substitution. Temperature-dependent resistivity, magnetic susceptibility, and Hall effect measurements reveal a linear suppression of density wave transition temperature $ T{\text{dw}}$ and a concurrent enhancement of hole concentration with increasing Cu content. At higher substitution levels ($ x > 0.15$ ), the transition-induced anomaly in the resistivity becomes undetectable while a magnetic signature persists, indicating a partial decoupling of spin and charge components and the possible survival of short-range spin correlations. The absence of superconductivity across the substitution series highlights the importance of additional factors in stabilizing the superconducting state in pressurized La$ _{4}$ Ni$ _{3}$ O$ _{10}$ .
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
13 pages, 4 figures
Singular density correlations in chiral active fluids in three dimensions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-14 20:00 EDT
Yuta Kuroda, Takeshi Kawasaki, Kunimasa Miyazaki
We investigate density fluctuations in three-dimensional chiral active fluids by using a simple particle model of helical self-propelled particles. Each particle is driven by a self-propelled force and a constant uniaxial chiral torque, whose direction is identical for all particles. Due to the helical nature of the particle motion, the system is generically anisotropic even when it is spatially homogeneous. Numerical simulations demonstrate that the helicity induces an anisotropic pattern and a singularity in the static structure factor (the density correlation function in Fourier space) in the low-wavenumber limit. Moreover, the system in the limit of infinite persistence time exhibits hyperuniformity in the direction perpendicular to the chiral torque, while giant density fluctuations emerge along the parallel direction. We then construct a fluctuating hydrodynamic theory for the system to describe the singular behavior. A linear analysis of the resulting equations yields an analytical expression for the static structure factor, which qualitatively agrees with our numerical findings.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
12 pages, 5 figures
Probing electron spin dynamics in single telecom InAs(P)/InP quantum dots using the Hanle effect
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
Maja Wasiluk, Helena Janowska, Anna Musiał, Johann P. Reithmaier, Mohamed Benyoucef, Wojciech Rudno-Rudziński
Spins of carriers confined in quantum dots (QDs) are promising candidates for qubits due to their relatively long spin relaxation times. However, the electron spin dephasing, primarily driven by hyperfine interactions with nuclear spins, can limit their coherence. Here, we report the first Hanle effect demonstration in single InAs(P)/InP QDs emitting in the telecom C-band leading to experimental determination of electron spin dephasing time. Using polarization-resolved photoluminescence spectroscopy, we identified excitonic complexes and confirmed the presence of a negatively charged trion, exhibiting a degree of circular polarization (DOCP) of $ -36%$ under quasi–resonant excitation. From the analysis of Hanle linewidth and employing a previously reported value of the electron $ g$ -factor, we extracted an electron spin dephasing time of $ T_2^{\ast} = 1.59 \pm 0.49~\mathrm{ns}$ . Despite the large indium nuclear spin, the obtained $ T_2^{\ast}$ is comparable to values reported for GaAs-based QDs, which we attribute to the larger volume of the InAs(P)/InP QDs. These findings confirm the potential of InP-based telecom QDs for use in spin-photon interfaces.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
This manuscript has been submitted to Applied Physics Letters for publication
Distinct Lifetimes for $X$ and $Z$ Loop Measurements in a Majorana Tetron Device
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-14 20:00 EDT
Morteza Aghaee, Zulfi Alam, Rikke Andersen, Mariusz Andrzejczuk, Andrey Antipov, Mikhail Astafev, Lukas Avilovas, Ahmad Azizimanesh, Bela Bauer, Jonathan Becker, Umesh Kumar Bhaskar, Andrea G. Boa, Srini Boddapati, Nichlaus Bohac, Jouri D.S. Bommer, Jan Borovsky, Léo Bourdet, Samuel Boutin, Lucas Casparis, Srivatsa Chakravarthi, Hamidreza Chalabi, Benjamin J. Chapman, Nikolaos Chatzaras, Tzu-Chiao Chien, Jason Cho, Patrick Codd, William Cole, Paul W. Cooper, Fabiano Corsetti, Ajuan Cui, Tareq El Dandachi, Celine Dinesen, Andreas Ekefjärd, Saeed Fallahi, Luca Galletti, Geoffrey C. Gardner, Gonzalo Leon Gonzalez, Deshan Govender, Flavio Griggio, Ruben Grigoryan, Sebastian Grijalva, Sergei Gronin, Jan Gukelberger, Marzie Hamdast, A. Ben Hamida, Esben Bork Hansen, Caroline Tynell Hansen, Sebastian Heedt, Samantha Ho, Laurens Holgaard, Kevin van Hoogdalem, John Hornibrook, Lovro Ivancevic, Max Jantos, Thomas Jensen, Jaspreet Singh Jhoja, Jeffrey C Jones, Vidul Joshi, Konstantin V. Kalashnikov, Ray Kallaher, Rachpon Kalra, Farhad Karimi, Torsten Karzig, Seth Kimes, Evelyn King, Maren Elisabeth Kloster, Christina Knapp, Jonne V. Koski, Pasi Kostamo, Tom Laeven, Jeffrey Lai, Gijs de Lange, Thorvald W. Larsen, Kyunghoon Lee, Kongyi Li, Guangze Li, Shuang Liang, Tyler Lindemann, Matthew Looij, Marijn Lucas, Roman Lutchyn, Morten Hannibal Madsen, Nasiari Madulid, Michael J. Manfra, Laveena Manjunath, Signe Markussen, Esteban Martinez, Marco Mattila, J. R. Mattinson, R. P. G. McNeil, Alba Pérez Millan, Ryan V. Mishmash, Sarang Mittal, Christian Møllgaard, M. W. A. de Moor, Eduardo Puchol Morejon, Trevor Morgan, George Moussa, B.P. Nabar, Anirudh Narla
We present a hardware realization and measurements of a tetron qubit device in a superconductor-semiconductor heterostructure. The device architecture contains two parallel superconducting nanowires, which support four Majorana zero modes (MZMs) when tuned into the topological phase, and a trivial superconducting backbone. Two distinct readout interferometers are formed by connecting the superconducting structure to a series of quantum dots. We perform single-shot interferometric measurements of the fermion parity for the two loops, designed to implement Pauli-$ X$ and $ Z$ measurements of the tetron. Performing repeated single-shot measurements yields two widely separated time scales $ \tau_X = 14.5\pm 0.3 , \mathrm{\mu s}$ and $ \tau_Z = 12.4\pm 0.4, \mathrm{ms}$ for parity switches observed in the $ X$ and $ Z$ measurement loops, which we attribute to intra-wire parity switches and external quasiparticle poisoning, respectively. We estimate assignment errors of $ \mathrm{err}^X_a=16%$ and $ \mathrm{err}^Z_a=0.5%$ for $ X$ and $ Z$ measurement-based operations, respectively.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)