Disordered Systems and Neural Networks
Non-zero Momentum Implies Long-Range Entanglement When Translation Symmetry is Broken in 1D
Amanda Gatto Lamas and Taylor L. Hughes
A result by Gioia and Wang [Phys Rev X 12, 031007 (2022)] showed that translationally symmetric states having nonzero momentum are necessarily long range entangled (LRE). Here, we consider the question: can a notion of momentum for non-translation symmetric states directly encode the nature of their
entanglement, as it does for translation symmetric states? We show the answer is affirmative for 1D systems, while higher dimensional extensions and topologically ordered systems require further work. While Gioia and Wang's result applies to states connected via finite depth
quantum circuits to a translation symmetric state, it is often impractical to find such a
circuit to determine the nature of the
entanglement of states that break translation
symmetry. Here, instead of translation eigenstates, we focus on the many-body momentum distribution and the expectation value of the translation operator in many-body states of systems having broken translation
symmetry. We show that in the continuum limit the magnitude of the expectation value of the translation operator $|<T>|$ necessarily goes to $1$ for delocalized states, a proxy for LRE states in 1D systems. This result can be seen as a momentum-space version of Resta's formula for the localization length. We investigate how accurate our results are in different
lattice models with and without well-defined continuum limits. To that end, we introduce two models: a deterministic version of the random dimer model, illustrating the role of the thermodynamic and continuum limits for our result at a
lattice level, and a simplified version of the Aubry-Andre model, with commensurate hopping for both momentum and position space. Finally, we use the random dimer model as a test case for the accuracy of $|<T>|$ as a localization (and thus
entanglement) probe for 1D periodic
lattice models without a well-defined continuum limit.
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Disordered Systems and Neural Networks
Learning Nonlinear Heterogeneity in Physical Kolmogorov-Arnold Networks
Fabiana Taglietti, Andrea Pulici, Maxwell Roxburgh et al. (+10 more)
Physical neural networks typically train linear synaptic weights while treating device nonlinearities as fixed. We show the opposite - by training the synaptic nonlinearity itself, as in Kolmogorov-Arnold Network (KAN) architectures, we yield markedly higher task performance per physical resource and improved performance-parameter scaling than conventional linear weight-based networks, demonstrating ability of KAN
topologies to exploit reconfigurable nonlinear physical dynamics. We experimentally realise physical KANs in silicon-on-
insulator devices we term 'Synaptic Nonlinear Elements' (SYNEs), operating at room temperature, microampere currents, 2 MHz speeds and ~750 fJ per nonlinear operation, with no observed degradation over 10^13 measurements and months-long timescales. We demonstrate nonlinear function regression, classification, and prediction of Li-Ion battery dynamics from noisy real-world multi-sensor data. Physical KANs outperform equivalently-parameterised software multilayer perceptron networks across all tasks, with up to two orders of magnitude fewer parameters, and two orders of magnitude fewer devices than linear weight based physical networks. These results establish learned physical nonlinearity as a hardware-native computational primitive for compact and efficient learning systems, and SYNE devices as effective substrates for heterogenous nonlinear computing.
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All authors Fabiana Taglietti, Andrea Pulici, Maxwell Roxburgh, Gabriele Seguini, Ian Vidamour, Stephan Menzel, Edoardo Franco, Michele Laus, Eleni Vasilaki, Michele Perego, Thomas J. Hayward, Marco Fanciulli, Jack C. Gartside
Superconductivity
Theory of Andreev and shot noise spectroscopy for topological superconductors probed by $s$-wave superconducting tips
Jushin Tei, Ryo Hanai, Satoshi Fujimoto et al. (+1 more)
Scanning tunneling microscopy (STM) and spectroscopy (STS) with $s$-wave superconducting tips has been widely applied to probe exotic
superconductors, but its potential for investigating topological
superconductors remains unclear. In junctions between an $s$-wave
superconductor and a topological
superconductor, the dominant tunneling process is Andreev reflection, in which Cooper pairs from the $s$-wave
superconductor tunnel as particle–hole excitations into the surface state of the topological
superconductor. In this work, we theoretically investigate the fundamental properties of Andreev and shot noise spectroscopy on topological
superconductors, focusing on the $dI/dV$ characteristics and current noise. We develop a real-time description of an effective tunneling action incorporating Andreev reflection processes in the Keldysh formalism and derive analytical expressions for the Andreev reflection current and the associated current noise. Furthermore, we perform numerical simulations for representative topological
superconductors and provide a catalog of $dI/dV$ spectra and the Fano factor. Our results establish guidelines for probing topological superconductivity using STM with $s$-wave superconducting tips, and provide theoretical
benchmarks for future STS experiments.
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All authors Jushin Tei, Ryo Hanai, Satoshi Fujimoto, Takeshi Mizushima
Mesoscale and Nanoscale Physics
Majorana Fermions in spin up and down electronic complexes in spin-orbit coupled array of semiconductor quantum dots in proximity to $s$-type superconductor and in magnetic field
Mijanur Islam, Mahan Mohseni, Ibsal Assi et al. (+2 more)
Semiconductor-s-type
superconductor nanowires host spinful
fermions and cannot be reduced to a single spinless Kitaev chain hosting single Majorana zero mode. Instead, such systems can be converted into two coupled p-wave Kitaev-like chains associated with different
spin sectors. Using the bond
Fermion transformation and exact diagonalization, we analyze parity resolved spectra and local spectral functions, demonstrating that zero-energy modes strongly localized at the system boundaries emerge only in one effective chain. Inter-chain coupling lifts parity degeneracy and redistributes the low-energy spectral weight, providing a controlled framework to assess the stability of Majorana-like modes in the finite spinful nanowires.
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All authors Mijanur Islam, Mahan Mohseni, Ibsal Assi, Daniel Miravet, Pawel Hawrylak
Materials Science
3D bulk-resolved $g$-wave altermagnetic order parameter in CrSb
Mengmeng Long, Theodore I. Weinberger, Zheyu Wu et al. (+7 more)
Electronic phases of matter, such as magnetism and superconductivity, are defined and distinguished by their order parameters quantifying the spontaneous
symmetry breaking underlying each phase. Simple cases include the uniform magnetisation of ferromagnets and isotropic gap function of conventional
superconductors. Unconventional
superconductors often have a nodal gap function, where the gap changes sign at nodes on the
Fermi surface. This concept of unconventional/nodal order parameter
symmetry has recently been extended to numerous
magnetic systems, including altermagnets, in which up- and down-
spin species are non-degenerate around the
Fermi surface. Here we demonstrate that
magnetic quantum oscillation measurements can provide a high resolution, bulk-sensitive, 3D mapping of the order parameter in an unconventional magnet. By rotating a
magnetic field through high- and low-
symmetry directions of the CrSb Brillouin zone, we show that this material's altermagnetic band structure leads to a reduction of
symmetry for each
spin-split
Fermi sheet away from nodal orientations. In momentum space, the exchange splitting between up and down
spins follows the profile of the $\mathcal{Y}_{4}^{-3}=zy(3x^2-y^2)$ real spherical harmonic - analogous to a $g$-orbital of the hydrogen atom. While notoriously difficult to resolve in unconventional
superconductors, our work demonstrates that the order parameter
symmetry of unconventional magnets can be precisely mapped via
quantum-oscillatory quasiparticle spectroscopy, establishing CrSb as a prototypical $g$-wave metallic altermagnet.
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All authors Mengmeng Long, Theodore I. Weinberger, Zheyu Wu, Mads F. Hansen, Ran Tao, Mridul Shrestha, Dave Graf, Yurii Skourski, F. Malte Grosche, Alexander G. Eaton
Mesoscale and Nanoscale Physics
Strain-tunable magnetic correlations in spin liquid candidate Nb$_3$Cl$_8$
Tharindu Fernando and Ting Cao
Recent research suggests the possibility of the two-dimensional breathing-Kagome magnet Nb$_3$Cl$_8$ hosting a
quantum spin liquid state, warranting further study into its
magnetic properties. Using ab initio calculations, we show that monolayer Nb$_3$Cl$_8$ has short-range
antiferromagnetic correlations among Nb$_3$ trimers with S = 1/2, and becomes magnetically frustrated due to the underlying effective triangular
lattice geometry, and is evidenced by a frustration index of f > 1. The high-temperature susceptibility shows a negative Weiss temperature from Monte Carlo calculations. Considering
spin-orbit coupling, we investigate the
magnetic anisotropy, including anisotropic exchange, single-ion anisotropy and the Dzyaloshinskii-Moriya interaction using the four-state energy mapping formalism. Although the elements have relatively small atomic numbers, the Dzyaloshinskii-Moriya interaction is comparable in magnitude to the anisotropic exchange. Additionally, we show that biaxial strain tunes the short-range correlations between
antiferromagnetic, paramagnetic and
ferromagnetic. These findings strengthen our understanding of Nb$_3$Cl$_8$ and advance its applications in current condensed matter physics and materials science research, including nanoscale mechanical and spintronics applications.
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Soft Condensed Matter
Diffusive buckling fronts in lattice-based metamaterials
Jochem G. Meijer, Faadil H. Shaik, Victoria V. McDermott et al. (+1 more)
Mechanical metamaterials can be designed to exhibit unique mechanical properties, including tunable auxetic behavior as well as multi-stability, which arise from the geometry and configuration of the constituent building blocks.
Lattice-based metamaterials, in particular, provide lightweight platforms where local instabilities can dictate the global response, with applications in energy routing and vibration isolation. In underdamped structures, perturbations have been found to propagate as nonlinear waves, e.g., transition waves or
solitons. Here we investigate the opposite limit of overdamped, highly dissipative
lattice metamaterials. Focusing on three-dimensional structures, we uncover how buckling instabilities, triggered by compression, propagate as fronts that shape the macroscopic behavior. We demonstrate in experiments on 3D-printed simple cubic
lattices how global and local buckling modes can be controlled via the
lattice geometry. By incorporating viscoelastic dissipation into a 3D-continuum model, we show that strain-driven buckling fronts obey coupled reaction-
diffusion equations. The
diffusion and reaction coefficients, determined by local geometry, material properties, and strain, select the propagation direction and enable steering of the fronts. This establishes a predictive and experimentally validated framework for the control of cascading mechanical instabilities in
lattice-based metamaterials.
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All authors Jochem G. Meijer, Faadil H. Shaik, Victoria V. McDermott, Heinrich M. Jaeger
Superconductivity
A Modulated Electron Lattice (MEL) Criterion for Metallic Superconductivity
Jaehwahn Kim, Davis A. Rens, Waqas Khalid et al. (+1 more)
A central unresolved question in the theory of superconductivity is why only a small subset of metallic elements exhibit a superconducting state, whereas many others remain strictly normal. Neither the conventional Bardeen Cooper Schrieffer (BCS) framework nor its extensions involving charge density wave (CDW) or pair density wave (PDW) order provide a predictive or material-selective criterion capable of distinguishing superconducting metals from non-superconducting ones. In particular, the persistent absence of superconductivity in simple noble metals with well-defined
Fermi surfaces poses a challenge for all traditional approaches. Here we address this problem using the Modulated Electron
Lattice (MEL) Ginzburg Landau (GL) framework introduced in our previous work. In this formulation, a coarse-grained MEL charge field $\rho_{\mathrm{MEL}}(\mathbf{r})$ with momentum dependent stiffness $\alpha(q)$ is coupled to the superconducting (SC) order parameter $\psi(\mathbf{r})$. We show that metallic superconductivity emerges only when the system satisfies a specific “MEL enhancement window,” characterized by a negative minimum of $\alpha(q)$ at either a finite modulation wave vector $q^{\ast}$ or at $q=0$, together with sufficiently strong coupling between $\rho_{\mathrm{MEL}}$ and $\psi$. This unified criterion naturally partitions metallic elements into three universal classes: (i) MEL-enhanced
superconductors with a finite-$q^{\ast}$ charge mode, (ii) conventional BCS
superconductors as the homogeneous $q^{\ast}=0$ limit of the MEL framework, and (iii) metals for which $\alpha(q)$ remains positive for all $q$, suppressing all MEL modes and preventing any superconducting instability. By applying this criterion to simple metallic elements, we identify why some metals develop superconductivity while others do not, possibly resolving a selection problem long open within the BCS paradigm.
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All authors Jaehwahn Kim, Davis A. Rens, Waqas Khalid, Hyunchul Kim
Strongly Correlated Electrons
Shi Feng and Nandini Trivedi
Quantum spin liquids (QSLs) host a variety of fractionalized particles. In Kitaev's paradigmatic honeycomb model a
spin-$\tfrac{1}{2}$ fractionalizes into $Z_2$ flux due to emergent $Z_2$ gauge field and matter Majorana
fermions. Although these excitations have well-defined dynamics in the integrable limit, their direct experimental identification is notoriously challenging: realistic materials inevitably host additional
symmetry-allowed interactions that break integrability and hybridize gauge and matter sectors, while
magnetic fields, which are often required to suppress competing order and stabilize a putative QSL regime, further entangle the responses of different fractionalized quasiparticles and may even drive the system into field-induced
spin-
liquid phases that are not adiabatically connected to the integrable limit. A prominent example is the
quantum Majorana metal, in which the distinct dynamics of fractionalized Majorana
fermions can become directly visible in scattering. This review highlights recent progress on these related questions: in which field-stabilized QSL regimes and nearby emergent phases, and under what conditions, can the response of a specific fractionalized quasiparticle be isolated and positively understood, thereby clarifying the existence and the experimental scope of putative
spin liquids? We review the progress on these questions across Abelian, non-Abelian, and emergent
quantum phases under
magnetic field that are not perturbatively connected to the integrable limit. We connect these field-induced dynamical phenomena to concrete experimental observables, relevant for
neutron scattering, resonant inelastic X-ray scattering, and pump-probe spectroscopy, techniques that are capable of identifying the nature of different
magnetic-field-induced phases and resolving specific types of fractionalized particles, including Majoranas and $Z_2$ fluxes.
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Soft Condensed Matter
Fracture initiation in silicate glasses via a universal shear localization mechanism
Matthieu Bourguignon, Gustavo Alberto Rosales-Sosa, Yoshinari Kato et al. (+6 more)
Shear bands lie at the root of fracture initiation in bulk metallic glasses and amorphous
polymers. For silicate glasses, in contrast, studies have largely emphasized permanent volumetric strain, commonly referred to as densification. Here we systematically investigate indentation-induced fracture in two distinct families of aluminoborosilicate glasses. The results demonstrate that plastic shear flow plays a decisive role in governing fracture initiation. In addition, molecular dynamics simulations reveal a pronounced composition dependence of softening associated with plastic shear flow, closely mirroring the experimentally observed propensity for strain localization. We conclude that silicate glasses conform to a universal pattern of rupture initiation governed by localization of shear-deformation, aligning with a broad range of amorphous materials, including bulk metallic glasses and glassy
polymers.
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All authors Matthieu Bourguignon, Gustavo Alberto Rosales-Sosa, Yoshinari Kato, Bruno Bresson, Hikaru Ikeda, Shingo Nakane, Gergely Molnár, Hiroki Yamazaki, Etienne Barthel
Materials Science
Nanoscopy of Excitons in Atomically Thin In-Plane Heterostructures with Nanointerfaces
Mahdi Ghafariasl, Tianyi Zhang, Sampath Gamage et al. (+8 more)
Atomically sharp 2D in-plane
heterostructures with nanoscale interfaces provide a powerful platform for tailoring optical and electrical properties at the nanoscale, enabling novel device engineering and the exploration of new physical phenomena. However, direct experimental correlation between local dielectric response and excitonic properties across such interfaces has remained elusive. Here, we probed the nanoscale complex dielectric function and the corresponding localized photoluminescence (PL) modulations in
heterostructure domains of lateral monolayer MoxW1-xS2 - WxMo1-xS2, synthesized using a
liquid-phase precursor-assisted approach. Near-field nano imaging across the visible-near-infrared range enables real space mapping of sharp amplitude and phase changes at the heterointerface, resolving the local complex dielectric function with nano-meter scale spatial resolution. Excitation energy-dependent nano spectroscopy reveals a reversal of dielectric contrast between Mo-rich and W-rich domains at their respective excitonic resonances, consistent with Lorentz-oscillator fits. Complementary hyperspectral nano-PL mapping resolves the
evolution of excitonic emission across the lateral heterointerface, with neutral-
exciton intensities varying continuously from W-rich to Mo-rich regions. Effective-medium theory modeling of the imaginary part of the effective dielectric function of the
heterostructure as a function of
photon energy and Mo filling fraction reproduces the observed excitonic trends, linking the PL
evolution to a composition-dependent dielectric response. Together, these results provide direct nanoscale correlation between dielectric and excitonic boundaries in laterally stitched monolayer
heterostructures and establish a
multimodal near-field spectroscopy framework for probing excitonic phenomena at the nanoscale.
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All authors Mahdi Ghafariasl, Tianyi Zhang, Sampath Gamage, Da Zhou, Muhammad Asjad, Sarabpreet Singh, Antonio Gomez-Rodriguez, Diego M. Solis, Venkataraman Swaminathan, Mauricio Terrones, Yohannes Abate
Soft Condensed Matter
Tissue shape from cell-scale active tensions
Nikolas H. Claussen, Fridtjof Brauns and Boris I. Shraiman
Connecting
cell and tissue mechanics is a fundamental challenge in the physics of morphogenesis. Conventional elasticity theory is generally inapplicable: cytoskeletal turnover precludes a fixed reference state, and the dominant forces are generated actively, independently of strain. Here, we study epithelia in quasi-static force balance between intracellular pressure and active interfacial tensions. The theory starts from a prescribed set of active tensions, represented as a Maxwell-Cremona tension triangulation dual to the
cell tiling. This
geometric formulation brings to bear the mathematics of discrete conformal geometry. Using generalized Voronoi diagrams, we construct the mechanically balanced
cell tiling resulting from the given tensions and compute the tissue-scale stress. Conceptually, we treat
cell interfaces as force dipoles whose
embedding in physical space -the
cell tiling- is determined by force balance. The tensions define an effective reference state in which the macroscopic stress vanishes as pressures and tensions cancel locally. Deformations from this reference result in macroscopic stress, constituting an emergent form of elasticity. Adiabatic tension dynamics change the reference shape. Thus, rather than fluidizing, tissues can deform -or "morph"-, while resisting external forces like a solid. We also define a conformal-
geometric representation of
cell network
topology, remodeled by plastic
cell rearrangement. We make experimentally testable predictions, notably that macroscopic stress is independent of local tension anisotropy. Overall, the unified description of emergent elasticity and plastic flow in epithelia is a step towards a theory of morphogenesis that puts active forces first and reflects the differences between inert and biological matter. Our framework also applies to 2D fluid foams and to frictionless granular media via a mechanical duality.
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Superconductivity
Lumped-Element Model of THz HEB Mixer Based on Sputtered MgB2 Thin Film
Changyun Yoo, Changsub Kim, Daniel P. Cunnane et al. (+1 more)
We present a comprehensive analysis and experimental study of THz hot-electron bolometer (HEB) mixers made from 40-nm-thick sputtered magnesium diboride (MgB2) thin films on high-resistivity silicon substrates. Using a lumped-element bolometric model, we achieve strong quantitative agreement with measurements of conversion gain, noise temperature, and local-oscillator (LO) coupling to the HEB devices. Our analysis shows that the sensitivity of current HEB devices is primarily limited by on-chip optical losses, with both Johnson and thermal-fluctuation noise contributing significantly to the overall noise temperature. Simulations of an optimized device with near-ideal optical coupling suggest that Johnson noise remains a substantial factor even with improved coupling. Further reduction of the noise temperature may require additional suppression of Johnson noise (via improved intrinsic conversion gain) beyond optimizing optical coupling efficiency. We emphasize the importance of accurate modeling to achieve good numerical agreement with experiments, thereby enabling understanding of the causes of sensitivity loss.
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All authors Changyun Yoo, Changsub Kim, Daniel P. Cunnane, Boris S. Karasik
Strongly Correlated Electrons
Chirality and quasi-long-range order in finite-flux Gutzwiller states for magnetized frustrated magnets
Wen O. Wang, Urban F. P. Seifert, Oleg A. Starykh et al. (+1 more)
We study Gutzwiller-projected wavefunctions for triangular-
lattice U(1) Dirac
spin liquids in a Zeeman field, where we allow the U(1) gauge field to develop a gauge flux, resulting in (
spin-split) spinon Landau levels. We find that at a given magnetization, the optimal candidate state has a finite flux chosen such that the spinon filling lies in a $|C|=1$ Landau-level gap: it gives the lowest variational energy and the smallest energy variance within our correlation-
matrix reconstruction for local Heisenberg-type models. By
symmetry, we argue that the finite gauge flux results in a non-zero (staggered) scalar
spin chirality, as also numerically observed, and further find that the $|C|=1$ state exhibits dominant quasi-long-ranged $120^\circ$
magnetic correlations. Studying the next-to-optimal wavefunction with a $|C|=2$ Landau-level gap, we observe unusual
spin-nematic correlations. Our results may provide guidance for analyzing the
magnetic-field response of DSL candidate materials and offer numerical diagnostics that can connect to the underlying theory of spinons coupled to an emergent U(1) gauge field.
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All authors Wen O. Wang, Urban F. P. Seifert, Oleg A. Starykh, Leon Balents
Mesoscale and Nanoscale Physics
A comparative study of perturbative and nonequilibrium Green's function approaches for Floquet sidebands in periodically driven quantum systems
Karun Gadge, Marco Merboldt, Michael Schüler et al. (+6 more)
We compare two complementary theoretical approaches to compute and interpret Floquet sidebands in periodically driven
quantum materials: a first-order perturbative approach (first-order perturbative Born approximation, PB1) and time-dependent nonequilibrium Green's functions (tdNEGF). Using
graphene as a model Dirac system, we disentangle in pump-probe setups Floquet-dressed initial states, Volkov-dressed final states (also known as
laser-assisted photoelectric effect, LAPE), and their interference. We quantify how photoemission
matrix elements, polarization, incidence angle, and near-surface screening shape the momentum-resolved sideband intensity observed in tr-ARPES. PB1 yields an analytical expression for the momentum-dependent sideband intensity, and for
graphene it captures the correct
symmetry trends, such as the magnitude of the intensities when considering the interference between the Floquet and Volkov states and photoemission
matrix elements. tdNEGF reproduces the full energy-momentum-resolved spectra, including hybridization gaps and spectral-weight redistribution. We find qualitative agreement between PB1 and tdNEGF once
matrix elements are included; quantitative differences arise near hybridization regions and at specific angles where higher-order processes and self-energies are essential. Thus, for systems with simple band structures and away from these regions, the two approaches can be used in a complementary way.
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All authors Karun Gadge, Marco Merboldt, Michael Schüler, Jan Philipp Bange, Wiebke Bennecke, Michael A. Sentef, Marcel Reutzel, Stefan Mathias, Salvatore R. Manmana
Soft Condensed Matter
Coupled concentration-charge dynamics in asymmetric 1:1 electrolytes, local transient response and fluctuations
Thê Hoang Ngoc Minh, Sleeba Varghese and Benjamin Rotenberg
We investigate the coupled dynamics of concentration and charge in asymmetric 1:1 electrolytes, focusing on the interplay between
diffusion asymmetry and external electric fields. Using Brownian dynamics simulations and linearized
stochastic density functional theory (SDFT), we analyze the transient response of charge and number currents to inhomogeneous electric fields, as well as the steady-state spatio-temporal fluctuations under uniform fields. Our results reveal that asymmetry in ionic
diffusion coefficients introduces a non-trivial coupling between charge and number transport, which modifies the two relaxation modes already present in symmetric electrolytes – a fast one associated with charge relaxation and a slow one linked to ambipolar
diffusion. The dynamics are further modulated by the applied field, which enhances
diffusion, alters screening lengths, and induces oscillatory behavior in the relaxation modes. The SDFT framework provides closed-form expressions for the intermediate scattering
matrix, capturing the dynamics of density fluctuations and cross-correlations between number and charge. These predictions are validated by simulations, demonstrating excellent agreement across a wide range of wave vectors, both at
equilibrium and under a finite electric field. Our findings highlight the critical role of
diffusion asymmetry and external fields in tuning the transport properties of electrolytes, with implications for nanofluidic devices, energy harvesting, and iontronic
circuits. This work bridges theoretical insights with practical applications, offering a robust framework for understanding and controlling electrolyte dynamics in asymmetric systems.
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Strongly Correlated Electrons
Pressure Tuning of Electronic Correlations and Flat Bands in CsCr$_3$Sb$_5$
Maria Chatzieleftheriou, Jonas B. Profe, Ying Li et al. (+1 more)
CsCr$_3$Sb$_5$ is a newly identified strongly correlated kagome
superconductor, characterized by non-
Fermi-
liquid behavior at elevated temperatures and intertwined charge- and
spin-density-wave order below $T_{DW}\approx 54$K. Under external pressure, this order is suppressed and a superconducting phase emerges. This phase diagram, which closely resembles that of high-$T_c$
superconductors, together with a kagome flat band near the
Fermi level and possible altermagnetic order, has motivated extensive theoretical and experimental investigations. To better understand how pressure influences the ordered states, we present a systematic study of the
evolution of the electronic properties under applied pressure. Performing DFT+DMFT (density functional theory combined with dynamical mean field theory) calculations, we uncover a complex interplay between the redistribution of spectral weight in the flat bands and the strength of electronic correlations under pressure. Our results further strengthen the interpretation that pressure effectively weakens electronic correlations through enhanced orbital hybridization. This, in turn, strongly suggests that superconductivity emerges as a direct consequence of the suppression of the system's ordered phase.
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All authors Maria Chatzieleftheriou, Jonas B. Profe, Ying Li, Roser Valentí
Strongly Correlated Electrons
Deconfined quantum criticality with internal supersymmetry
Zhi-Qiang Gao, Hui Yang and Yan-Qi Wang
Deconfined
quantum critical point (DQCP) describes direct, non-fine-tuned
quantum phase transition between two ordered phases that break distinct and seemingly unrelated
symmetries, providing a route to continuous phase transition beyond the conventional Ginzburg–Landau paradigm. In this work we extend the DQCP paradigm to systems with internal supersymmetry (SUSY), where the on-site
Hilbert space furnishes a representation of a Lie superalgebra, and the
Hamiltonian is invariant under the corresponding Lie supergroup. Focusing on the minimal supersymmetric generalization of
spin $SU(2)$, namely $OSp(1|2)$, we propose a supersymmetric deconfined
quantum critical point (sDQCP) between a phase that breaks internal $OSp(1|2)$ and a phase that instead breaks
lattice rotation
symmetry. We formulate a non-linear sigma model on the supersphere target space that captures the
symmetry intertwinement characteristic of the sDQCP, and we further develop a gauge theory description to address its dynamical properties, including a heuristic argument for 3D XY critical behavior. Finally, we show that explicitly breaking $OSp(1|2)$ down to $SU(2)$ continuously connects our sDQCP to the conventional DQCP scenario.
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Statistical Mechanics
Optimal control of bit erasure in stochastic random access memory
Songela W. Chen and David T. Limmer
Energy costs of information processing are growing exponentially. Bit erasure is a key problem in this energy-information nexus, and a number of seminal relationships have been deduced regarding the relationship between thermodynamic costs and
memory storage. To continue making progress in the modern era, however, requires confronting thermodynamic costs in realistic physical systems which operate away from
equilibrium. Here, we explore the thermodynamic costs of bit erasure in a complementary metal
oxide semiconductor model of two types of random access
memory. We find dynamic random access
memory dissipates the least amount of energy when operated in the quasistatic limit, where errors are also minimized. By contrast, static random access
memory is most efficiently operated in finite time due to the energy required to maintain the state of the bit. We demonstrate a numerically robust optimization scheme using mean field theory and automatic differentiation, finding optimal protocols compatible with electrical engineering insights. These results provide a framework for operating realistic
circuits in thermodynamically advantageous ways.
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Superconductivity
Vortex-parity-controlled diode effect in Corbino topological Josephson junctions
Joon Young Park, Thomas Werkmeister, Jonathan Zauberman et al. (+11 more)
Nonreciprocal supercurrents in Josephson junctions have recently emerged as a sensitive tool for investigating broken
symmetries in superconducting
quantum materials. Here, we report an even-odd Josephson diode effect (JDE) in Corbino-geometry junctions fabricated on the pristine surface of a bulk-insulating three-dimensional topological
insulator (3DTI). We find that the diode polarity, which indicates the preferred direction of supercurrent flow, robustly alternates its sign depending on the parity (even or odd) of the enclosed
vortex number. This behavior is absent in two key control devices: a non-topological
graphene Corbino Josephson junction and a 3DTI-based linear Josephson junction. These results indicate that the polarity-tunable JDE is intrinsically linked to the unique combination of the proximitized topological superconductivity in the 3DTI surface and the Corbino device's closed-loop geometry. Our theoretical modeling attributes the observed sign change in diode polarity to the alternating sign of periodic boundary conditions in topological
superconductors, supporting the interpretation that the
vortex-parity-controlled JDE is a direct manifestation of the underlying Andreev bound state
topology associated with the presence of non-Abelian anyons in the
vortices.
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All authors Joon Young Park, Thomas Werkmeister, Jonathan Zauberman, Omri Lesser, Laurel E. Anderson, Yuval Ronen, Cristian J. Medina Cea, Satya K. Kushwaha, Kenji Watanabe, Takashi Taniguchi, Robert J. Cava, Yuval Oreg, Amir Yacoby, Philip Kim