Mesoscale and Nanoscale Physics · Cross-listed from quant-ph
FAlCon: A unified framework for algorithmic control of quantum dot devices
Tyler J. Kovach, Daniel Schug, Zach D. Merino et al. (+3 more)
As
spin-based
quantum systems scale, their setup and control complexity increase sharply. In
semiconductor quantum dot (QD) experiments, device-to-device variability, heterogeneous control-electronics stacks, and differing operational modalities make it difficult to reuse characterization, calibration, and control logic across laboratories. We present FAlCon, an open-source software ecosystem for portable, automated characterization and tuning measurement workflows. FAlCon provides (i) a lightweight domain-specific
language for expressing state-based tuning logic in a hardware-agnostic form; (ii) specialized transmittable libraries of physics-informed QD data structures (“tuning vernacula”); and (iii) extensible libraries of shared measurement protocols enabling an interoperable lab-agnostic measurement stack. By separating
algorithm intent from instrument realization, while preserving traceability and supporting typed scripting, FAlCon enables researchers and engineers to exchange, adapt, and deploy characterization and autotuning routines across heterogeneous QD setups. The framework supports all users, ranging from end users running prebuilt
algorithms with custom initial conditions to developers extending instrumentation support and contributing new tuning strategies. Although the present release targets QD experiments, other
qubit modalities and scientific experiments could reuse FAlCon's modular abstractions by providing new tuning data types and instrument control templates.
Read the full abstract ▾
All authors Tyler J. Kovach, Daniel Schug, Zach D. Merino, Mark Friesen, Mark A. Eriksson, Justyna P. Zwolak
Strongly Correlated Electrons
Discerning ground state and photoemission-induced spin textures in altermagnetic $\alpha$-MnTe
D.A. Usanov, S.W. D'Souza, A. Dal Din et al. (+12 more)
The recently discovered class of altermagnets provide a physical realization of an unconventional compensated
magnetic phase with a higher partial-wave type of ordering, reminiscent of unconventional superfluid phases. Their stability under normal conditions has sparked significant research interest, spanning fields from spintronics to topological and correlated
quantum materials.
Spin- and angle-resolved photoemission spectroscopy (SARPES) has great promise to resolve the momentum-dependent
spin textures, which are intricately interweaved with the altermagnetic direct space
spin order. Using the relativistic $d$-wave-like collinear
spin polarization on one of the non-relativistic nodal surfaces of the altermagnetic band structure of $\alpha$-MnTe as an example, we here identify and resolve the challenges associated with (S)ARPES studies on altermagnets. We focus particularly on the role of photoemission-induced electron polarization and the coupling between light and the Néel vector of a
magnetic domain. Our findings reveal an atypical behaviour of photoemission selection rules while using linearly-polarized light. Our methods allow to distinguish polarization of photoelectrons originating from the sample's ground state
spin texture, on one hand, and from the photoemission process, on the other hand. Our experimental results are supported by a combination of ab initio band-structure and 1-step photoemission calculations.
Read the full abstract ▾
All authors D.A. Usanov, S.W. D'Souza, A. Dal Din, J. Krempaský, F. Guo, O.J. Amin, C. Polley, M. Leandersson, G. Carbone, B. Thiagarajan, T. Jungwirth, L. Šmejkal, J. Minár, P. Wadley, J.H. Dil
Materials Science
Ligand-Controlled Phonon Dynamics in CsPbBr3 Nanocrystals Revealed by Machine-Learned Interatomic Potentials
Seungjun Cha, Chen Wang, Victor Fung et al. (+1 more)
Halide perovskite nanocrystals are leading candidates for next-generation optoelectronics, yet the role of surface ligands in controlling their
phonon dynamics remains poorly understood. These dynamics critically govern nonradiative relaxation, energy up-conversion, and
phonon-assisted anti-Stokes emission. Conventional ab initio methods, while accurate, are computationally infeasible for experimentally relevant nanocrystal sizes that require thousands of atoms to capture realistic ligand shells and dynamic disorder at finite temperatures. Here, we introduce a machine- learned interatomic potential fine-tuned on small CsPbBr3 nanocrystals with diverse ligands, enabling accurate prediction of ligand-induced
phonon properties far beyond the spatial and temporal scales of ab initio methods. We find that both cationic and anionic ligands systematically
redshift Pb-Br-Pb stretching modes while blueshifting the PbBr64- octahedral rotation mode, with stronger overall effects for anionic passivation. Notably, anionic ligands stiffen the rotation mode non-monotonically with respect to the ligand binding energy. Our findings reveal important roles of cationic and anionic ligands in modulating key dynamic modes of halide perovskite nanocrystals associated with detrimental nonradiative losses, offering mechanistic insights and design principles for high-performance perovskite nanocrystal optoelectronics.
Read the full abstract ▾
All authors Seungjun Cha, Chen Wang, Victor Fung, Guoxiang Hu
Materials Science · Cross-listed from physics.ins-det
Advances in the Fabrication of On-chip Superconducting Integral Field Units for CMB and Line-Intensity Astronomy
L. G. G. Olde Scholtenhuis, D. Perez Capelo, K. Karatsu et al. (+7 more)
Studying the polarization and spectral distortion of the
Cosmic Microwave Background (CMB) in tandem with intensity fluctuations of the
Cosmic Infrared Background (CIB) allows us to verify our assumptions on
cosmic inflation and investigate the dynamics and
evolution of
galaxy clusters in the last 10 billion years. Because of its broadband emission and being an all-sky extended source, observing the entire CMB in detail is a very time-consuming and expensive exercise. Fortunately, in the last few years, the on-chip superconducting spectrometer technology has moved out of the lab and into the
telescope. With its compact size and background-limited sensitivity, this family of instruments is particularly well-suited for fast and large area observations in a relatively unexplored range of the electromagnetic spectrum. However, recent examples of this technology do not yet reach the requirements needed for large spectroscopic and polarimetric surveys of the CMB. We formulate several of these requirements and introduce novel on-chip components and fabrication techniques. We introduce a cross-over to enable distinguishing signal polarization, minimize signal loss by locally optimized lithography of a coplanar-waveguide (CPW), lower the spectral resolution of microstrip filters by deposition of a dielectric layer, and increase the yield of the spectrometer array by removing individual line shorts. These together have culminated in the successful fabrication of a fourteen-spaxel IFU.
Read the full abstract ▾
All authors L. G. G. Olde Scholtenhuis, D. Perez Capelo, K. Karatsu, D. J. Thoen, A. J. van der Linden, S. O. Dabironezare, L. H. Marting, J. J. A. Baselmans, S. Vollebregt, A. Endo
Materials Science
$\mathrm{Cs_3V_9Te_{13}}$: A New Vanadium-Based Material with a Reuleaux-Triangle-Like Lattice and a Possible Phase Transition near 48 K
Zhen Zhao, Jianping Sun, Xin-Wei Yi et al. (+10 more)
Exploring and synthesizing materials with new
crystal structures provides an important route to discovering exotic
quantum phenomena. However, materials with unconventional
lattice geometries remain largely unexplored. Here, we report the discovery of a new vanadium-based material, $\mathrm{Cs_3V_9Te_{13}}$, featuring a Reuleaux-triangle-like
lattice. Electrical transport and
magnetic measurements consistently reveal an anomaly near 48 K, and this feature shows little sensitivity to the applied
magnetic field. A corresponding anomaly is also observed in the
Hall coefficient near 48 K, indicating a marked change in the carrier response. In addition, temperature-dependent x-ray diffraction results indicate no obvious structural change across 48 K. Taken together, these results suggest that the anomaly is not induced by the structural transition, but associated to a possible electronic and/or
magnetic phase transition. High-pressure transport measurements and first-principles calculations further reveal a highly tunable electronic state in $\mathrm{Cs_3V_9Te_{13}}$, with the kagome-like electronic feature and pressure-suppressed antiferromagnetism. These results demonstrate this material, with its structurally novel Reuleaux-triangle-like
lattice, as a new platform for exploring the interplay between nontrivial
lattice geometry and emergent physical phenomena.
Read the full abstract ▾
All authors Zhen Zhao, Jianping Sun, Xin-Wei Yi, Ruwen Wang, Lin Zhu, Tong Liu, Haisen Liu, Hui Guo, Wu Zhou, Jinguang Cheng, Gang Su, Haitao Yang, Hong-Jun Gao
Materials Science
Plasticity from Symmetry: A Gauge-Theoretic Framework
Kevin T. Grosvenor, Mario Solís and Piotr Surówka
Plastic deformation is widely regarded as an intrinsically dissipative phenomenon and its theoretical description is largely phenomenological. We argue instead that plasticity possesses a non-dissipative,
symmetry determined backbone: defect kinematics are fixed by
symmetry prior to dissipation and separate from constitutive assumptions. Starting from the spontaneous breaking of spacetime
symmetries in a crystalline phase, we construct an effective field theory in which elasticity and geometry reorganize into a coupled higher-rank tensor vector gauge structure. The gauge fields are not postulated, rather they emerge naturally from stress and defect conservation laws. Dislocations, disclinations, and torsional defects appear as gauge charges of non-integrable geometry whose continuity equations and mobility constraints follow directly from Gauss laws. This clarifies the long-standing ambiguity over which variables are fundamental in the gauge theory of defects and shows that plasticity admits an ideal gauge-theoretic formulation, with dissipative flow arising as a controlled deformation of this conservative theory.
Read the full abstract ▾
Strongly Correlated Electrons
Quantum Algorithms to Determine Spin-Resolved Exchange-Correlation Potential for Strongly Correlated Materials
H. Arslan Hashim, Volodymyr M. Turkowski and Eduardo R. Mucciolo
Accurate exchange-correlation (XC) potentials are essential for density functional theory, yet reliable approximations remain challenging for strongly correlated systems. In this work, we present a
quantum algorithmic framework to determine
spin-resolved XC potentials using a variational
quantum eigensolver. Using the Hubbard model as a prototypical strongly correlated
lattice system, we prepare ground states in fixed
spin sectors through a
Hamiltonian variational ansatz initialized from the non-interacting $(U=0)$ Slater-determinant ground state. From the resulting many-body ground states, we extract the XC energy and compute the corresponding
spin-resolved XC potentials via finite differences. The accuracy of the approach is benchmarked against exact diagonalization for one- and two-dimensional Hubbard systems of various
lattice sizes. We demonstrate that the variational ansatz reproduces the ground-state energies and densities with high fidelity, enabling accurate construction of both
magnetic and non-
magnetic XC potentials. We analyzed the dependence of the XC potentials on the interaction strength, charge,
spin densities, and magnetization. We also present an empirical complexity scaling relation for the computational cost of the method at a fixed fidelity. These results illustrate how
quantum computing can be used to construct
spin-resolved XC functionals for correlated
lattice models, providing a potential pathway for improving density functional approximations in strongly correlated materials.
Read the full abstract ▾
Materials Science
Fully anharmonic calculations of the free energy of migration of point defects in UO2 and PuO2
Dillon G. Frost, Johann Bouchet, Mihai-Cosmin Marinica et al. (+3 more)
Calculating
diffusion rates of point defects in materials typically relies on the harmonic approximation to estimate migration free energies. However, anharmonic effects can have a large impact on
diffusion properties, and explicitly accounting for them is usually computationally demanding and difficult to achieve in practice. In this work, we investigate the role of anharmonic effects on defect migration in UO2 and PuO2 using the potential of average force integration (PAFI) method. Fully anharmonic migration free energies are computed for several cation and anion defect types, using the Cooper-Rushton-Grimes (CRG) potential and a recently developed machine learning spectral neighbour analysis potential (SNAP) for UO2. Results are systematically compared to harmonic estimates based on attempt frequencies and the Debye approximation. Our results reveal that the validity of the harmonic approximation strongly depends on the defect type and the underlying potential, with significant deviations observed in several cases. In particular, defect migration barriers are found to decrease strongly with increasing temperature (up to 1 eV between 0 and 1200 K), and anharmonic contributions can substantially modify migration
entropies and, consequently,
diffusion coefficients. Comparing defect migration in UO2 and PuO2 using the CRG potential reveals that PuO2 has lower migration enthalpies at 0~K for all considered defects, but this is compensated by higher attempt frequencies, resulting in similar overall jump frequencies in UO2 and PuO2. These findings provide insight into the limitations of commonly used approximations and highlight the importance of anharmonic effects for predictive modeling of
diffusion in
nuclear fuels as well as in other classes of materials.
Read the full abstract ▾
All authors Dillon G. Frost, Johann Bouchet, Mihai-Cosmin Marinica, Clovis Lapointe, Jean-Bernard Maillet, Luca Messina
Strongly Correlated Electrons
Quasiparticle properties below coherence onset in YbAl3 nanostructures
Dale T. Lowder, Gage Eichman, Yuxin Wan et al. (+9 more)
Mesoscopic transport measurements are underexplored as probes of quasiparticles and their properties in correlated metals. The mixed valence compound YbAl$_3$ exhibits a single-ion Kondo temperature of 670 K, while thermodynamic and transport properties (probed with specific heat,
magnetic susceptibility,
Hall effect, and resistivity) imply the onset of coherence of heavy
fermion quasiparticles at T$* \approx$ 37 K. To characterize these quasiparticles, we utilize mesoscopic techniques familiar from weakly correlated conductors. In lithographically-defined nanowires etched from epitaxial films, we observe weak antilocalization magnetoresistance and universal conductance fluctuations, consistent with electronic coherence lengths of tens of nanometers. Additionally, analysis of Johnson-Nyquist noise measurements as a function of bias current reveal, within the context of a range of accepted models, a significant electron-
phonon energy loss that increases with decreasing temperature, a finding that we contextualize within the broader properties of YbAl$_3$.
Read the full abstract ▾
All authors Dale T. Lowder, Gage Eichman, Yuxin Wan, Karthik Rao, Ruiwen Xie, Hongbin Zhang, Debjoty Paul, Shouvik Chatterjee, Darrell G. Schlom, Kyle Shen, Emilia Morosan, Douglas Natelson
Strongly Correlated Electrons
Joel Bobadilla and Alberto Camjayi
Antiferromagnets are attractive for spintronics owing to their vanishing net magnetization and ultrafast
spin dynamics, yet their
spin-compensated electronic structure has long confined them to passive roles. Here we identify a
symmetry selection rule that overcomes this limitation: in a collinear antiferromagnet, a
spin-polarized dc charge current requires the simultaneous breaking of particle–hole
symmetry and of the equivalence between the two
magnetic sublattices, either one alone leaving the polarization identically zero. We demonstrate the rule in the doped
antiferromagnetic Hubbard model within dynamical mean-field theory: doping and a uniform
magnetic field each break one of the two
symmetries, and electronic correlations convert the resulting hierarchy of
spin-dependent scattering rates into a sizable, field-tunable polarization of the charge current. The polarization is largest deep in the ordered phase and reverses sign at an emergent compensation point, not dictated by
symmetry, at which the dominant conducting
spin species is interchanged. In correlated altermagnetic Hubbard models, the same two
symmetries are broken structurally, by the sublattice-alternating hopping pattern: the field-driven mechanism identified here and the altermagnetic one are two realizations of a single selection rule. Electronic correlations thus emerge as an active ingredient for spintronics in structurally conventional collinear antiferromagnets.
Read the full abstract ▾
Mesoscale and Nanoscale Physics · Cross-listed from quant-ph
Stroboscopic detection of itinerant microwave photons
Hanna Zeller, Lukas Danner, Max Hofheinz et al. (+3 more)
We present a novel scheme to detect itinerant microwave radiation at the single
photon level. Using existing Josephson-photonics devices, where two microwave cavities are coupled by a dc-voltage biased superconducting junction, we theoretically show how to implement a stroboscopically repeated, near-projective measurement of a
photon impinging on one of the cavities. Optimizing rate, duration, and strength of the measurement by flux control of the junction and developing a threshold protocol to detect the
photon from a homodyne measurement of the radiation output of the other cavity, we achieve highly efficient detection with low dark counts. By cascading the detector with a preamplifier, where a similar two-cavity Josephson-photonics device acts as a
photon multiplier, we can further improve the device to reach a detection efficiency of $88.5 \%$ with a dark count rate of $\sim10^{-4} \gamma_a$, set by the resonance width $\gamma_a$ of the absorbing cavity. These results for a multiplication factor of two suggest that near-unity efficiencies may be reached for higher multiplication factors.
Read the full abstract ▾
All authors Hanna Zeller, Lukas Danner, Max Hofheinz, Ciprian Padurariu, Joachim Ankerhold, Björn Kubala
Soft Condensed Matter
Time reversal breaking of colloidal particles in cells
Gabriel Knotz, Till M. Muenker, Timo Betz et al. (+1 more)
We investigate signatures of broken time reversal
symmetry in
stochastic trajectory data, employing the previously introduced three point correlation called mean back relaxation. We specifically investigate data from a simple driven model, as well as from colloidal particles within living or passivated biological
cells. Both in the model as well as in
cell data, MBR detects broken time reversal
symmetry, and furthermore, allows to determine relevant time and length scales of activity. For the
cells, we show, by applying various drugs, that it is predominantly the presence of microtubules which is needed for a time reversal
symmetry breaking. We employ a bound for
entropy production, finding that it is in striking relation to previously determined active energies that quantify violation of the fluctuation dissipation
theorem.
Read the full abstract ▾
All authors Gabriel Knotz, Till M. Muenker, Timo Betz, Matthias Krüger
Other Condensed Matter · Cross-listed from quant-ph
Dark state role in time-reversal symmetry breaking
Dario Fasone, Rita Veilande, Luigi Giannelli et al. (+5 more)
We investigate the role of the global driving phase $\Phi$ in the dynamics of driven few-level
quantum systems, a central setting in coherent control of atomic, molecular, and solid-state platforms. In particular, we focus on systems with closed-loop couplings, where external driving fields induce interference effects that strongly influence population transfer and
symmetry properties of time-
evolution. While full time-reversal
symmetry requires $\Phi=0,\pi$, leading to a real
Hamiltonian, we focus on a less restrictive transformation, the phase inversion (or complex conjugation of the
Hamiltonian), under which population dynamics can remain symmetric even though coherences generally do not. We show that the presence of a dark (spectator) state is a sufficient condition for this population phase
symmetry (P$\Phi$S), as it constrains the dynamics to reduced subspaces characterized by SU(2) or open-loop SU(3)
evolution. We analyze this mechanism in three- and four-level systems and derive general conditions for P$\Phi$S that extend to generic $n$-level configurations, with $n$ even. These findings provide practical guidelines for achieving robust control in
quantum systems, with potential applications in
quantum information processing and
quantum computing.
Read the full abstract ▾
All authors Dario Fasone, Rita Veilande, Luigi Giannelli, Giuseppe A. Falci, Teodora Kirova, Sandro Wimberger, Thomas Zanon-Willette, Ennio Arimondo
Disordered Systems and Neural Networks · Cross-listed from quant-ph
Monte Carlo sampling from a projected entangled-pair state in simulations of quantum annealing in the three dimensional random Ising model
Jacek Dziarmaga
Quantum annealing with the D-Wave Advantage system in the random Ising model on a cubic
lattice is simulated using a three-dimensional (3D) tensor network. The
Hamiltonian is driven across a
quantum phase transition from a paramagnetic phase to a
spin-glass phase. The network is represented as a tensor product state, also known-particularly in two dimensions-as a projected entangled-pair state (PEPS). The annealing procedure is repeated for a range of annealing times in order to test the Kibble-Zurek (KZ) power law governing the residual energy at the end of the annealing ramp. For an infinite
lattice with periodic nearest-neighbor random Ising couplings, the final energy is evaluated using a deterministic method. For a finite
lattice with open boundaries, we introduce a more efficient Monte Carlo sampling approach. In both cases, the residual energy as a function of annealing time approaches the KZ power law as the annealing time increases.
Read the full abstract ▾
Statistical Mechanics
Fractal and Spectral Dimensions as Determinants of Thermal Ablation Outcomes in Cancer Tissues
Mario Olmo-Fajardo, Alexander López, Malte Henkel et al. (+1 more)
Clinical thermal ablation outcomes display significant variability that classical bio-heat models cannot fully explain. One reason may lie in the fractal architecture of biological tissues, which has been identified as a robust biomarker directly correlated with cancer grades. This structural heterogeneity, together with
memory effects (e.g., thermotolerance), causes heat transfer in living tissues to differ from
Fourier diffusion, resulting in anomalous biological transport. In this work, we implemented a realistic fractal-fractional bio-heat model, with non-linear perfusion and PI-controlled power delivery, to quantify the role of tissue fractality in ablation outcomes. Our results reveal that the expansion of coagulation zones is jointly controlled by fractal geometry and its associated topological connectivity. These findings highlight spectral dimension as a key driver of clinical variability, successfully reproducing the reduced ablative efficacy in liver metastases compared to primary carcinomas, and provide evidence for topologically informed treatment strategies for the thermal ablation of malignant neoplasms.
Read the full abstract ▾
All authors Mario Olmo-Fajardo, Alexander López, Malte Henkel, Sébastien Fumeron
Materials Science
Anharmonicity Driven by Vacancy Ordering Unlocks High-performance Thermoelectric Conversion in Defective Chalcopyrites II-III$_2$-VI$_4$
Hui Zhang, Jincheng Yue, Jiongzhi Zheng et al. (+8 more)
Defective chalcopyrites have recently emerged as promising thermoelectric materials because their ordered intrinsic vacancies can profoundly reshape both
lattice dynamics and electronic structure. Here, we present a comprehensive theoretical investigation of the
lattice thermal and carrier transport properties of II-III$_2$-VI$_4$ defective chalcopyrites by combining first-principles calculations with machine-learning interatomic potentials. We show that vacancy ordering enhances
lattice distortion, leading to strong anharmonicity and metavalent bonding. The interplay of soft low-frequency
phonons, strongly negative Grüneisen parameters, and a substantially enlarged four-
phonon scattering phase space results in four-
phonon-scattering-dominated heat transport, yielding ultralow
lattice thermal conductivity. Meanwhile, systematic anion substitution at the VI-site provides an effective route to tune the electronic structure: reduced anion electronegativity weakens metal-anion hybridization, shifts anion $p$ states upward, narrows the band gap, and thereby improves electrical transport. Benefiting from this synergy between vacancy-induced
phonon suppression and anion-regulated electronic optimization, CdGa$_2$Te$_4$ exhibits an ultralow
lattice thermal conductivity of 0.19 W$\cdot$m$^{-1}$K$^{-1}$ and a high room-temperature $ZT$ of 0.957. This work not only predicts defective chalcopyrites as a promising platform for high-performance thermoelectrics but also provides a practical design strategy by integrating vacancy ordering, higher-order
phonon scattering, and anion-dependent band engineering.
Read the full abstract ▾
All authors Hui Zhang, Jincheng Yue, Jiongzhi Zheng, Ning Wang, Wenling Ren, Shuyao Lin, Chen Shen, Hao Gao, Yanhui Liu, Yue-Wen Fang, Tian Cui
Materials Science
Tritium for Nanoscale Hydrogen Analysis by Atom Probe Tomography
Maria Vrellou, Alexander Welle, Stefan Wagner et al. (+6 more)
Accurate nanoscale detection of hydrogen is essential for understanding hydrogen-related phenomena in materials, yet conventional tracing with deuterium is often complicated by residual background hydrogen. This study evaluates tritium as a highly resolvable isotopic marker for nanoscale hydrogen analysis in metals using atom probe
tomography. Titanium was selected for its ability to incorporate hydrogen isotopes, providing a suitable platform for tritium detection. Time of flight secondary ion mass spectrometry and electron backscatter diffraction were performed prior to tritium charging to characterize the initial composition and microstructure. Atom probe
tomography in
laser mode before and after tritium charging, at three post-charging time intervals, enables tracking of tritium incorporation over time. Thermal desorption analysis confirmed the presence of tritium and complemented the secondary ion mass spectrometry measurements, highlighting the role of the surface
oxide layer in modulating tritium release. While tritium, deuterium, and protium differ in their
diffusion and trapping behavior, the distinct mass signal associated with tritium provides a practical advantage for resolving hydrogen at very low concentrations. This work serves as a fundamental benchmarking study for leveraging tritium and atom probe
tomography as a combined tool for understanding hydrogen in materials, relevant for interpreting local processes such as hydrogen embrittlement.
Read the full abstract ▾
All authors Maria Vrellou, Alexander Welle, Stefan Wagner, Marco Weber, Rolf Rolli, Hans-Christian Schneider, Astrid Pundt, Xufei Fang, Christoph Kirchlechner
Statistical Mechanics · Cross-listed from quant-ph
Quantum Fisher Information for Entropy of Gibbs States
Francis J. Headley
We derive the
quantum Fisher information for
entropy estimation in a Gibbs state and show that it equals the inverse of the heat capacity, which is dual to the temperature Fisher information given by the heat capacity divided by the square of the temperature. Their product is independent of the
Hamiltonian and depends only on the temperature, leading to a metrological uncertainty relation between the variances of
entropy and temperature
estimators in which all system-specific quantities cancel. This relation arises from the dually-flat structure of the Gibbs exponential family expressed in thermodynamic coordinates, and holds for all standard thermodynamically conjugate pairs. We identify energy measurement as the optimal protocol for
entropy estimation, analyse critical-point scaling where the
entropy Fisher information vanishes, and connect it to the Ruppeiner metric in
entropy coordinates. We lastly examine the distinguished role of the von Neumann
entropy within the Rényi family. Generalisations to the grand canonical and generalised Gibbs ensembles are given.
Read the full abstract ▾
Mesoscale and Nanoscale Physics
Electron Tesla valve
Daniil I. Sarypov, Dmitriy A. Pokhabov, Arthur G. Pogosov et al. (+3 more)
In solids, frequent electron-electron collisions can induce collective, fluid-like electron transport. While this regime offers a powerful framework for exploring many-body phenomena, there is still a lack in functional electronic device actively exploiting hydrodynamic behaviour of electrons. Here, we introduce a solid-state analogue of a Tesla valve $\unicode{x2013}$ a passive fluidic diode that rectifies flow without moving parts. Lithographically defined in high-mobility GaAs two-dimensional electron gas, the device exhibits abrupt rectification producing a more than tenfold difference between forward and reverse resistances. This threshold behaviour, reminiscent of the onset of
turbulence in fluidic Tesla valves, points to the emergence of turbulent regime in the electron
liquid $\unicode{x2013}$ a long-predicted, but yet unobserved state of electronic matter. More broadly, our work demonstrates the fruitfulness of the hydrodynamic analogy: fluidic technologies can be readily adopted to create novel electronic devices. Here, this is realized through a solid-state rectifier whose operation relies on a new physical mechanism, interparticle collisions.
Read the full abstract ▾
All authors Daniil I. Sarypov, Dmitriy A. Pokhabov, Arthur G. Pogosov, Evgeny Yu. Zhdanov, Andrey A. Shevyrin, Askhat K. Bakarov
Quantum Gases
Quantized transport of solitons in Bose-Einstein condensates driven by spin-orbit coupling
Yaroslav V. Kartashov, Vladimir V. Konotop and Dmitry A. Zezyulin
We demonstrate that linear and nonlinear Thouless pumping can be realized in two-component elongated Bose-Einstein condensates using helicoidal
spin-orbit coupling that slides with respect to a static optical
lattice, identical for both spinor components. Stable quantized transport is found for
solitons in semi-infinite and finite gaps, within certain intervals of chemical potentials and numbers of atoms. In the semi-infinite gap, the transport is arrested for
solitons with sufficiently large number of atoms. We elucidate the important role of Zeeman splitting in the control of quantized transport, which disappears when the longitudinal component of the Zeeman field is removed.
Read the full abstract ▾
Materials Science
Early Prediction of Creep Failure via Bayesian Inference of Evolving Barriers
Juan Carlos Verano-Espitia, Tero Mäkinen, Mikko J. Alava et al. (+1 more)
Creep under a sustained load can persist for long times yet culminate in abrupt yielding or rupture, implying a finite lifetime even when the material appears solid. Here, we formulate lifetime prediction as
Bayesian inference over an evolving activation-energy landscape. A time-dependent distribution of activation barriers controls deformation: stress lowers barriers, while irreversible rearrangements deplete the weakest sites and reshape the low-barrier tail. Using early-time acoustic emission data,
Bayesian inference estimates the evolving barrier statistics in each sample and yields posterior predictive distributions for the time-to-failure. This approach provides online uncertainty-aware lifetime forecasts – already at around 10~% of the sample lifetime – that link microscopic barrier
evolution to macroscopic creep dynamics.
Read the full abstract ▾
All authors Juan Carlos Verano-Espitia, Tero Mäkinen, Mikko J. Alava, Jérôme Weiss
Mesoscale and Nanoscale Physics
Twist-angle-dependent quantum phase diagrams in twisted bilayer MoTe2
Zheng Sun, Fan Xu, Jiayi Li et al. (+17 more)
Two-dimensional semiconducting moiré superlattices provide a highly tunable platform for investigating strongly correlated and topological
quantum phases. As a prototypical example, twisted
bilayer MoTe2 (tMoTe2) has been shown to host fractional topological phases at zero
magnetic field. However, their
evolution with twist angle and competition with other correlated
quantum states remain largely unexplored. Here we report a systematic transport study of twist-angle-dependent phase diagrams in tMoTe2 across a range of 3.79{\deg}-5.76{\deg}, revealing an
evolution from valley-polarized, fractional topological states to valley-degenerate correlated states and superconductivity. At relatively small twist angles, partially-filled Chern bands of tMoTe2 host fractional
quantum anomalous
Hall (FQAH) states following the Jain sequence, together with signatures of an anomalous composite
Fermi liquid at moiré hole filling factor {\nu}h = 1/2. Increasing twist angle progressively suppresses fractional topological phases and reconstructs the half-filled Chern band into
symmetry-breaking integer Chern insulating states. At {\nu}h = 1, we observe a transition from robust integer
quantum anomalous
Hall (IQAH)
insulators at small angles to displacement-field-tuned, topologically trivial correlated
insulators at larger angles. Remarkably, at twist angles above approximately 5.6{\deg}, superconductivity emerges adjacent to the {\nu}h = 1 correlated
insulator, with a phase diagram closely resembling that recently reported in twisted
bilayer WSe2. Our results uncover a unified twist-angle-driven phase
evolution linking fractional
topology,
symmetry breaking,
magnetic order, and superconductivity, providing new insight into the emergent
quantum phenomena in moiré systems.
Read the full abstract ▾
All authors Zheng Sun, Fan Xu, Jiayi Li, Yifan Jiang, Jingjing Gao, Cheng Xu, Tongtong Jia, Kehao Cheng, Shaozheng Wang, Wanghao Tian, Jinyang Zhang, Kenji Watanabe, Takashi Taniguchi, Jinfeng Jia, Shengwei Jiang, Yang Zhang, Yuanbo Zhang, Shiming Lei, Xiaoxue Liu, Tingxin Li
Materials Science
First-Principles Investigation of the Pressure Dependent Physical Properties of Intermetallic Kagome ZrRe2
Mst. Irin Naher, A. F. M. Yusuf Haider, Dholon Kumar Paul et al. (+3 more)
We present a density functional theory investigation of the pressure dependent structural, electronic, mechanical, thermophysical, vibrational, and optical properties of the intermetallic Kagome compound ZrRe2. The calculated ground-state structural parameters are in excellent agreement with available experimental results. The estimated structural parameters, elastic constants, and
phonon dispersion confirm the structural, chemical, mechanical, and dynamical stability of ZrRe2 up to 25 GPa. The Kagome feature in the material has been identified from the electronic band structure for the first time. ZrRe2 exhibits topological feature at 0 GPa, which vanishes under 25 GPa.
Fermi surface (FS) analysis predicts that ZrRe2 could potentially host a charge density wave (CDW) phase. The electronic and optical studies confirmed its metallic nature. The Debye temperature and
phonon thermal conductivity are moderate, while the melting point is relatively high. Furthermore, ZrRe2 possesses moderate electron-
phonon coupling, which weakens under pressure as the
phonon modes harden. Consequently, the superconducting transition temperature decreases with increasing pressure. Most of the properties studied and analyses performed in this paper are novel in nature.
Read the full abstract ▾
All authors Mst. Irin Naher, A. F. M. Yusuf Haider, Dholon Kumar Paul, Md Lutfor Rahman, Firoze H. Haque, Saleh Hasan Naqib
Mesoscale and Nanoscale Physics
Observation of a Reconstructed Chern Insulator in Twisted Bilayer MoTe2
Min Wu, Lingxiao Li, Yunze Ouyang et al. (+12 more)
Twisted
bilayer MoTe2 is a prototypical moire material in which long-wavelength superlattices amplify electron correlations, enabling a wealth of emergent
quantum phases. To date, experimental efforts have focused primarily on small twist angles (typically smaller than 4deg ), whereas the larger-angle regime-where moire bands become more dispersive and correlations are reduced-has remained largely unexplored. Here we chart the topological phase space of tMoTe2 at a relatively large twist angle of approximately 4.54deg, accessing a moderately correlated regime with enhanced bandwidth. In contrast to small-angle devices that predominantly host fractional
quantum anomalous
Hall or
spin Hall responses, we uncover multiple Chern-insulating states with C = 1 at moire fillings v = -1, -0.53 and -1/2. Strikingly, at v = -2/3 a
magnetic field induces a fractional Chern
insulator accompanied by an
insulator-metal transition. Our results broaden the topological phase diagram of tMoTe2 and establish large-angle moire superlattices as a versatile platform for engineering robust topological states beyond the strong-correlation limit.
Read the full abstract ▾
All authors Min Wu, Lingxiao Li, Yunze Ouyang, Yifan Jiang, Wenxuan Qiu, Zaizhe Zhang, Zihao Huo, Qiu Yang, Ming Tian, Neng Wan, Kenji Watanabe, Takashi Taniguchi, Shiming Lei, Fengcheng Wu, Xiaobo Lu
Materials Science · Cross-listed from physics.comp-ph
Tuning Cu/Diamond Interfacial Thermal Conductance via Nitrogen-Termination Engineering
Guang Yang, Xinling Tang, Zhongkang Lin et al. (+4 more)
Cu-diamond composites are recognized as promising high-thermal-conductivity candidates for electronic cooling, offering tunable properties and competitive cost. However, their performance is significantly limited by the poor Cu/diamond interfacial thermal conductance (ITC). Here, we propose a nitrogen-termination strategy to tune the ITC of Cu/diamond interfaces and unravel atomistic mechanisms by which nitride interlayers tailor
phonon transport. Based on the MACE machine-learning interatomic potential (MLIP) framework, we fine-tune the pre-trained MACE-MPA-0 foundation model by incorporating customized C-N-Cu training
datasets. Through MLIP-driven
lattice dynamics simulations, we demonstrate that an atomically flat N-termination on diamond enhances the ITC by 21% compared to the bare Cu/diamond interface. Mode-resolved
phonon spectroscopy reveals that the LA
phonons with frequency above 4 THz and wavevectors near {\Gamma}-X and {\Gamma}-U directions are selectively modulated by N-termination engineering. Analyses of local vibrational states and interfacial bonding further indicate that the N-termination on diamond tunes the interfacial heat conduction via surficial mass modification and bonding regulation, as evidenced by variations in LDOS overlap and COHP spectra. These findings open venues for tuning heat transfer across Cu/diamond interfaces via non-metallic modification, which avoids the graphitization issues associated with metallic coatings, and provide novel guidelines for upgrading the
phonon-mediated heat transfer in Cu-diamond composites.
Read the full abstract ▾
All authors Guang Yang, Xinling Tang, Zhongkang Lin, Yulin Gu, Wei Hao, Yujie Du, Xiaoguang Wei
Strongly Correlated Electrons
Altermagnetic pseudogap from $\frac{t}{U}$ expansion
Rohit Hegde
Order parameter analysis of the t/U series reveals a uniform altermagnet endemic to the doped Mott
insulator, driven by kinetic interactions, occupying a position between the antiferromagnet and hole-doped d-wave
superconductor that is normally reserved for the pseudogap. The metastable boundary of the altermagnet punctures and divides the
superconductor into underdoped and overdoped regions, reminiscent of the $T^\ast$ crossover or transition in the cuprates. Similarly, the $T_{pair}$ boundary of the
superconductor divides the altermagnet, leading to a low temperature phase susceptible to Cooper fluctuations. The altermagnet is unstable to inhomegeneous
spin and charge order of sites, bonds, and currents. Its leading instability is to the $\pi$-flux state, suggesting the possible emergence of
spin-charge
liquids and
quantum ordered states from a physically realistic microscopic model.
Read the full abstract ▾
Materials Science
Dopability limits in Al-rich AlGaN alloys for far-UVC LEDs
Ling Zhang, Miao Zhou and Alex M. Ganose
Transitioning to solid-state ultraviolet (UV) lighting is critical for reducing global energy utilization to meet net-zero targets. AlGaN-based far-UVC LEDs offer a mercury-free, energy-efficient alternative to conventional mercury lamps, yet their performance is severely bottlenecked by poor carrier injection at Al compositions exceeding 80%. Point defects are known to significantly affect carrier concentrations and radiative recombination efficiency, however, systematic studies of point defects in AlGaN
alloys remain scarce. In this work, we investigate intrinsic and extrinsic defects in high-Al-content Al$_{1-x}$Ga$_x$N
alloys ($x$ = 1/6, 1/4, and 1/3). We reveal that explicit
alloy modeling and proper treatment of the temperature dependence of the band gap are essential to bring calculated carrier concentrations in line with experimental observations. We uncover that Si dopants preferentially substitute minority Ga atoms, forming compensating negative-U DX centers in Al-rich environments that severely limit n-type conductivity. We identify carbon as the most detrimental unintentional
impurity, while the impact of oxygen and hydrogen is negligible in Si-doped samples typically used for devices. These findings highlight the significance of explicit
alloy modeling and provide valuable insights into the design of AlN-based
alloys.
Read the full abstract ▾
Mesoscale and Nanoscale Physics · Cross-listed from physics.optics
Superballistic transport of thermal photons in confined many-body systems
Jian Dong, Junming Zhao, Philippe Ben-Abdallah et al. (+1 more)
Ballistic transport, realized when the system size is smaller than the mean free path of energy carriers, is traditionally regarded as the ultimate limit for energy transfer. Here, we predict a superballistic radiative heat transport regime that surpasses this limit in dilute chains of plasmonic nanoparticles confined within cavities. This anomalous regime exhibits superlinear scaling of the effective thermal conductivity (k ~L^1.5) and originates from the amplification of long-range interactions mediated by cavity-guided modes. Our results establish a framework for ultrafast photonic heat transport and open pathways for thermal management, information processing and energy transfer in
quantum and nanoscale systems.
Read the full abstract ▾
All authors Jian Dong, Junming Zhao, Philippe Ben-Abdallah, Linhua Liu
Soft Condensed Matter
Towards the Multiscale Design of Pressure Sensitive Adhesives
Nicolas Moreno, Elnaz Zohravi, Shaghayegh Hamzehlou et al. (+6 more)
Pressure-sensitive adhesives (PSAs) are soft polymeric materials that exhibit complex rheological and mechanical behavior gov- erned by the interplay between
polymer architecture, crosslink density, and
entanglement constraints. Predicting their rheological properties from underlying microstructure remains a central challenge in adhesive design. In this work, we adopt a multiscale com- putational framework based on the Lagrangian Heterogeneous Multiscale Method (LHMM), coupling a macroscopic continuum description with a mesoscale
polymer network model featuring breakable bonds embedded in a viscous medium. The approach enables consistent information transfer across scales and captures both elastic network response and viscous dissipation. The framework is calibrated using experimental rheological data and tensile measurements for four PSA formulations with varying gel fractions and crosslink densities. The simulations reproduce key experimental trends in storage modulus (G'), loss modulus (G"), and tensile stress-strain behavior under planar extension, while differentiating the distinct mechanical signatures of each formula- tion. The results elucidate how crosslink density and effective network connectivity control stiffness, stress localization, and failure characteristics. Overall, the proposed multiscale methodology provides a predictive platform for linking microstructural design pa- rameters to macroscopic mechanical properties and offers a rational basis for the formulation and optimization of next-generation PSAs.
Read the full abstract ▾
All authors Nicolas Moreno, Elnaz Zohravi, Shaghayegh Hamzehlou, Edgar Patino-Narino, Malavika Raj, Mercedes Fernandez, Nicholas Ballard, Jose M. Asua, Marco Ellero
Mesoscale and Nanoscale Physics
Influence of sulphur vacancies on ultrafast charge separation in WS$_2$-graphene heterostructures
Johannes Gradl, Niklas Hofmann, Leonard Weigl et al. (+6 more)
Understanding how defects influence charge separation in WS$_2$-
graphene heterostructures is crucial for future applications in light harvesting and detection. Previous studies have reported widely varying lifetimes for the charge-separated state, all supposedly linked to electron trapping at sulphur vacancies. The exact impact of these defects, however, has remained unclear. Here, we deliberately introduce sulphur vacancies by annealing the
heterostructures at high temperatures in ultrahigh
vacuum. Angle-resolved photoemission spectroscopy (ARPES) reveals that these vacancies modify both the band
alignment and doping level of the
heterostructure. Time-resolved ARPES (trARPES) further shows that increasing the sulphur vacancy concentration prolongs the lifetime of electrons in the WS$_2$ conduction band but shortens the lifetime of the charge-separated state. Guided by model calculations, we attribute this behaviour to shifts in the energy
alignment between sulphur vacancy states and
graphene's Dirac point, combined with a reduced excitonic absorption. The model also yields a transfer time for electrons tunneling from sulphur vacancies into
graphene's Dirac cone of $\sim$4ps, consistent with our trARPES measurements. Our study clarifies the role of sulphur vacancies in WS$_2$-
graphene heterostructures, further improving our microscopic understanding of charge dynamics for future optoelectronic applications.
Read the full abstract ▾
All authors Johannes Gradl, Niklas Hofmann, Leonard Weigl, Stiven Forti, Neeraj Mishra, Camilla Coletti, Raul Perea-Causin, Ermin Malic, Isabella Gierz