Soft Condensed Matter
Folding-Driven Auxetic Weft Knit Textiles with Integrated Capacitive Sensing
Kausalya Mahadevan, Helen E. Read, Anya X. Zhang et al. (+3 more)
Machine knitting provides a scalable platform for manufacturing multifunctional textiles in which geometry, mechanics, and embedded functionality can be programmed at the stitch level. However, predictive design tools capable of linking knit architecture to large-deformation mechanical response remain limited. Here, we develop a reduced-order spring-network model that captures the relaxation, unfolding, and deformation of knitted fabrics composed of checkerboard arrangements of rib and garter patches. The model accurately predicts the corrugated relaxed configuration of the knits and the
evolution of local deformations under tensile loading using only linear extensional and torsional springs. Combining simulations with experiments, we show that the programmed unfolding of the corrugations generates tunable auxetic behavior, with both the magnitude of the negative Poisson's ratio and the strain at which it occurs governed by the unit-
cell geometry. We further integrate capacitive strain sensing directly during fabrication through partial plating of conductive yarns, eliminating post-processing. The resulting knitted capacitors exhibit programmable tradeoffs between strain sensitivity and sensing range, enabling either highly sensitive sensors over narrow deformation windows or lower-sensitivity sensors capable of measuring larger strains. Together, our modeling framework and fabrication strategy provide a route toward the rational design of mechanically programmable, sensorized knits with tailored shape-morphing and sensing functionalities.
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All authors Kausalya Mahadevan, Helen E. Read, Anya X. Zhang, Louis-Justin Tallot, Michelle C. Yuen, Katia Bertoldi
Mathematical Physics · Cross-listed from math.PR
Parameter-Space Heat Flow, Gaussian Density Ratios, and Sharp Hermite Truncation Rates
Jae Wan Shim
We reinterpret the classical Hermite generating function as a Gaussian density ratio: relative to the unit Gaussian reference, it is the density ratio of a Gaussian with shifted mean and unchanged covariance. Applying the heat
semigroup in the mean-parameter variable to this generating function produces the corresponding temperature variation. Thus the heat-
semigroup time variable is reinterpreted as the temperature variation of the Gaussian density ratio. This parameter-space formulation also gives a
parabolic control principle for Hermite approximation errors. Since Hermite projections act in the velocity variable and the heat flow acts in the mean variable, Hermite block energies and truncation tails are subsolutions of the same parameter-space heat equation. This remains useful for heat-evolved non-Gaussian perturbations where no usable closed coefficient formula is available. For Gaussian density ratios with general covariance, the Hermite coefficients satisfy a weighted homogeneity in the mean and covariance-defect parameters. This yields Ornstein–Uhlenbeck covariance, an exact generating function for total-degree Hermite block energies, and the sharp
geometric Hermite truncation rate, equal to the square root of the largest absolute covariance defect. We also derive precise isotropic block and tail asymptotics and interpret the estimates for near-Gaussian kinetic distributions.
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High Energy Astrophysical Phenomena
Caterina Tiburzi, M. T. Lam, D. J. Reardon et al. (+17 more)
The ionised media that permeate the Milky Way have been active topics of research since the discovery of
pulsars in 1967. In fact,
pulsars allow one to study several aspects of said
plasma, such as their column density,
turbulence, scattering measures, and discrete, intervening structures between the
neutron star and the observer, and aspects of the
magnetic field throughout. Such sources of information allow us to characterise the electron distribution in the terrestrial ionosphere, the
Solar Wind, and our
Galaxy and have an important impact on other experiments involving
pulsars such as
Pulsar Timing Arrays. In this article, we review the state-of-the-art of
plasma research using
pulsars, the aspects that should be taken into consideration for optimal
plasma studies, and we provide future perspectives on improvements to those enabled by the SKA.
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All authors Caterina Tiburzi, M. T. Lam, D. J. Reardon, N. K. Porayko, M. Mevius, S. K. Ocker, S. C. Susarla, J. R. Dawson, J. P. W. Verbiest, A. Deller, G. M. Shaifullah, N. D. R. Bhat, J.-M. Grießmeier, M. Walker, W. Jing, F. A. Iraci, M. Geyer, L. Levin, M. J. Keith, The SKA Pulsar Science Working Group
General Relativity and Quantum Cosmology · Cross-listed from math.DG
A conformal reduction for the X-ADM mass
Stephen McCormick
The X-ADM mass is a generalisation of the ADM mass for asymptotically flat
manifolds, recently introduced by Mantegazza and Oronzio [arXiv:2602.11372], who proved a positive mass
theorem for this quantity in dimension $3$ under a certain topological condition. In this article, we prove the X-positive mass
theorem with
rigidity in all dimensions $n\geq3$ without any topological restrictions. To this end, we first prove that the scalar
curvature condition appearing in the X-positive mass
theorem implies the metric is of positive Yamabe type. We then show that the X-ADM mass of the given metric is equal to the ADM mass of a scalar-flat representative in its conformal class plus a term that is explicitly non-negative. From this, the X-positive mass
theorem follows from the standard positive mass
theorem. As a corollary, we obtain the Riemannian mass–charge inequality of general relativity in all dimensions, which was previously only known for
spin manifolds. Finally, we give a version of the X-positive mass
theorem for a
manifold with boundary.
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Instrumentation and Methods for Astrophysics
Robo-AO-2: entering the era of automated science operations, hybrid wavefront sensing, and adaptive secondary integration
Christoph Baranec, Reed Riddle, James Ou et al. (+10 more)
We present the first science results and new technical milestones from the Robo-AO-2 facility at the University of Hawaii 2.2-m
telescope. Following successful commissioning, the system began science operations in 2025. We are starting a large-scale survey of young
stars in the Scorpius-Centaurus association to detect sub-
stellar companions, vetting the Habitable Worlds Observatory Target
Stars and Systems list, and discovering
stellar blends for TESS
exoplanet host candidates. We report on the commissioning of the natural guide
star wavefront sensor, supporting science and future hybrid
laser-
stellar sensing demonstrations. Finally, we detail the automation of the
telescope facility, Robo88, via updated
telescope control systems and absolute encoders, and the integration of Robo-AO-2 with the
telescope's new adaptive secondary mirror.
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All authors Christoph Baranec, Reed Riddle, James Ou, Ruihan Zhang, Guillaume Huber, Zachary Werber, Luke Mckay, Rachel Rampy, Michael C. Liu, Carl Ziegler, Mark Chun, Keith Powell, Marcos A. van Dam
Atmospheric and Oceanic Physics
Enhancing a high resolution data-driven weather prediction model with surface descriptors
Åsmund Bakketun, Håvard Homleid Haugen, Jostein Blyverket et al. (+2 more)
We study the importance of surface characteristics when
forecasting near-surface variables with a data-driven weather prediction model. To target the challenge of predicting small-scale weather conditions at high resolution, we introduce a range of surface descriptors in the training of a state-of-the-art data-driven model. The input data includes surface descriptors inherited from the numerical weather prediction model used to produce the training
dataset and topographic neighbourhood indices. We found that errors of 2-metre temperature and 10-metre wind speed forecasts were reduced by 1.9% and 3.0% respectively compared to a baseline model over the model domain. Over certain surfaces, the improvements were significantly larger. For example, we found a 12% reduction of temperature mean absolute errors over urban areas when the urban fraction was included in the model input. Furthermore, we investigated how the model responded to removal of glaciers, resulting in an increase of temperature. This indicates that 1) the model produce a physically reasonable response and 2) input
datasets can be updated without the need to retrain the model. The latter suggests a great benefit for operational systems as training is expensive compared to running these models. This study highlights the importance of including surface conditions in the prediction of near-surface variables.
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All authors Åsmund Bakketun, Håvard Homleid Haugen, Jostein Blyverket, Thomas Nils Nipen, Malte Müller
Materials Science
Twist-configured moire-moire reconstruction governs diverse commensurate double-moire phases in twisted bilayer graphene on h-BN
Yuta Seo, Naoto Nakatsuji, Jimpei Kawase et al. (+6 more)
The coexistence of multiple moire
lattices in van der Waals
heterostructures raises a fundamental question: how do distinct moire patterns interact and reconstruct? Here, we investigate twisted
bilayer graphene (tBG) on hexagonal boron nitride (h-BN), where tBG and
graphene/h-BN moire structures coexist, using conductive atomic force microscopy combined with continuum-model simulations. We show that reconstruction between these moire
lattices-moire-moire reconstruction-manifests across multiple length scales, giving rise to diverse commensurate double-moire phases. Locally, the stacking registry between the two moire
lattices is uniquely selected by the global twist configuration (helical or alternate), mediated by rotational relaxation of the shared
graphene layer. This registry, together with twist angle and strain, governs commensurate domains from C3z-symmetric to strained
symmetry-modified structures. These results establish moire-moire reconstruction as a general framework for engineering structural and electronic order – including theoretically predicted topological flat bands below the magic angle – in multilayer moire materials.
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All authors Yuta Seo, Naoto Nakatsuji, Jimpei Kawase, Naoto Hishida, Kenji Watanabe, Takashi Taniguchi, Takuto Kawakami, Mikito Koshino, Tomoki Machida
Physics and Society
From graphons to real-world networks: kinetic opinion dynamics under selective media influence
Bertram Düring, Martina Fraia and Alessandro Licciardi
We propose a kinetic model of opinion dynamics under selective media influence on both graphon-based and real-world networks. The media action, inspired by Hallin's theory of spheres, is incorporated through a model predictive control strategy designed to steer
agents' opinions toward a desired target opinion. For the resulting Boltzmann-type description, we analyse the
evolution of the moments and, in the quasi-invariant interaction limit, derive a Fokker–Planck-type equation together with a characterisation of its stationary states. We also prove exponential convergence to
equilibrium in the
Fourier metric. Numerical experiments are performed on networks generated by a Gaussian graphon and on real-world, single-issue Twitter networks, allowing us to investigate the role of control and interaction parameters, as well as the impact of the subset of
agents subject to media influence. Using real-world social networks data to initialise opinions and infer the interaction structure, we then compare the dynamics obtained on the original networks with those produced by Gaussian graphons fitted to their adjacency
matrices, thereby assessing the descriptive power of the graphon approach for real-world opinion dynamics.
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Medical Physics
Body Habitus Dominates Solver Choice as a Source of Uncertainty in MRI Safety Assessment of Active Implantable Medical Devices
Safa Hameed, Fuchang Jiang, Bhumi Bhusal et al. (+3 more)
MRI is increasingly critical for patients with active implantable medical devices (AIMDs), yet access depends on safety labeling derived from computational heating predictions under ISO/TS 10974 Tier 3. Published assessments have relied predominantly on a single electromagnetic solver class and one or two standard-BMI reference anatomies, leaving the relative contributions of solver choice, tissue property uncertainty, and patient anatomy to predictive variability uncharacterized within a common workflow. We performed a cross-platform evaluation of finite-difference time-domain (FDTD, Sim4Life) and finite element method (FEM, ANSYS HFSS) implementations of the full Tier 3 workflow for a deep
brain stimulation system at 1.5 T, extending the analysis across more than 250 clinically realistic trajectories spanning standard male and female references (Duke, HBM, Ella), an elderly male (Glenn), and elevated-BMI models of both sexes (Fats, Ella BMI 30). FDTD and FEM agreed closely in standard anatomies, with Maximum Allowable B1+ limits converging near 2.6-3.0 uT. The elderly male model produced a comparable limit to Duke, indicating BMI rather than age drives heating variability. Elevated BMI reduced safe B1+ by 19-31% in both sexes, while sex at matched BMI had no significant effect.
Geometric morphing approximated the native obese limit, whereas dielectric property sweeps failed to reproduce elevated-BMI heating distributions. Body habitus is the dominant source of predictive uncertainty in Tier 3 assessment, exceeding solver choice, dielectric assumptions, and sex. Anatomical diversity, including elevated-BMI female phenotypes, should be treated as a primary variable.
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All authors Safa Hameed, Fuchang Jiang, Bhumi Bhusal, Sana Ullah, Pia Sanpitak, Laleh Golestanirad
Atomic Physics
Reconfigurable Bitter-Type Electromagnet for Zeeman Slowing
Emma G. Hataway, Emma K. Falk, Kaia E. O'Neill et al. (+2 more)
Many Zeeman slower magnets are geometrically captured by a
vacuum chamber, preventing modification or repair without breaking
vacuum. We describe a Bitter-type electromagnet coil design that can be easily disassembled, reconfigured, repaired, and replaced without disturbing the
vacuum system. This coil, designed to slow lithium atoms, produces a near-ideal field profile with a single DC power supply. With a resistance of 5.7(9) m$\Omega$, an inductance of 8.8(2) $\mu$H, and switching times as low as $\sim100$ $\mu$s, the coil compares favorably to other designs, and can be disassembled, modified, and reassembled repeatedly without loss of performance. With forced-air cooling, the coil experiences moderate heating. This coil design offers greater flexibility than traditional electromagnet designs, and it can retrofitted onto existing UHV chambers.
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All authors Emma G. Hataway, Emma K. Falk, Kaia E. O'Neill, Morgan P. Berghof, Ben A. Olsen
Superconductivity
Theoretical investigation of power absorbed by superconductors with Rashba spin-orbit coupling in the presence external time-dependent perturbation
Reza Afzali, Bahman Takrim and Amir Hossein Asghari
The absorbed power in
superconductors driven by a time-dependent external perturbation is investigated through transitions between Bogoliubov quasiparticle states. The transition
matrix element contains the superconducting coherence factor, which determines the role of the gap, excitation spectrum, and external frequency in the absorption process. The formulation is applied to a Hubbard-model
superconductor including correlated hopping and Rashba
spin-orbit coupling. In this model, numerical calculations are used to obtain the quasiparticle energies, density of states, chemical potential, and temperature-dependent superconducting gap. The normalized absorbed power is then evaluated for different values of temperature, interaction strength, correlated hopping parameter, and
spin-orbit coupling strength. The results show that the absorption response is strongly affected by the superconducting gap and by changes in the quasiparticle spectrum. Rashba
spin-orbit coupling changes the density of states and therefore modifies the absorption. These results show that hopping processes, interaction strength, and
spin-orbit coupling play important roles in the ultrasonic and electromagnetic absorption of superconducting systems.
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Quantum Physics
An approach for calculating astrophysical opacities on quantum computers
Shivesh Pathak, Alina Kononov and Andrew D. Baczewski
We propose a
quantum algorithmic protocol for calculating astrophysical opacities. Our implementation uses first- and second-quantized representations of interacting electronic and photonic subsystems and
Hamiltonian simulation via the interaction picture. Inferring opacity from momentum-resolved measurements of the photonic register yields a direct relationship between
qubit count and spectral range/resolution. Logical resource estimates for the classically challenging problem of
solar iron opacity are comparable to another high-energy-density physics problem (Rubin et al., PNAS 121(3) (2024)).
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Quantum Physics
Locally Passive, Globally Charged Quantum Batteries: Coherence-Controlled Work and the Robustness of the Stored Charge
Asad Ali, Saif Al-kuwari and James Q. Quach
A solvable charger–battery model is introduced in which
quantum coherence controls both where a
quantum battery's charge is stored and how robustly it survives noise. Charging converts the charger's coherence into charger–battery
entanglement and splits the deposited work between a locally extractable part and a correlation-locked part accessible only through joint operations; for a
qubit, the split obeys an exact complementarity, and at maximal coherence, the battery is locally passive with the entire charge locked in correlations. Robustness follows local accessibility: the stored energy and locally extractable work are population-based, immune to pure dephasing, and limited only by relaxation, with an energy half-life, whereas the correlation-locked work is fragile to both dephasing and relaxation. Dephasing, global and local depolarization, and amplitude damping are treated through a single gain–loss competition
algebra, and the resulting storage lifetimes are made concrete with superconducting-transmon parameters.
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Instrumentation and Methods for Astrophysics
Tracing the Boundary of the South Atlantic Anomaly Region with SPHEREx Transient Flagging Rates
Chi H. Nguyen, James Bock, Sean Bryan et al. (+10 more)
The NASA SPHEREx satellite was launched in 03/2025 to survey the full sky between 0.75 - 5.0 um. The image processing of SPHEREx H2RG detectors includes real-time flagging of transient events during integration. SPHEREx follows a polar orbit passing over the South Atlantic Anomaly (SAA) zone multiple times daily, where the transient counts reach as high as >80% of pixels, depleting the pixel inventory for further analysis. The science pipeline flags all exposures taken while in the SAA for re-observation, as well as any with >10% transients regardless of the spacecraft location. After six months, ~1.5% of the exposures outside of the pre-defined SAA zone were flagged. While some exposures are adjacent to the edge of the SAA, the majority appear to trace the geomagnetic field near the poles. Given the importance of the SAA to designing and operating space instruments, in this paper we present the SAA boundary traced by SPHEREx transient flags as a reference for future mission.
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All authors Chi H. Nguyen, James Bock, Sean Bryan, Walter R. Cook, Brendan Crill, C. Darren Dowell, Olivier Doré, Beth Fabinsky, Candice Fazar, Howard Hui, Phillip Korngut, Steve Padin, Michael Zemcov
Optics
Coupling loss and transmission in a multimode fiber-fed virtually imaged phased array (VIPA)
Matthew C. H. Leung, Andrew Szentgyorgyi, Colby Jurgenson et al. (+1 more)
The Virtually Imaged Phased Array (VIPA) is a spectral disperser that has seen increasing adoption across various applications, including optical telecommunications, high-resolution spectroscopy, and
LiDAR. Although VIPAs are typically fed by single-mode optical fiber in these applications, there is growing interest in using a multimode optical fiber feed to enable higher throughput. However, a multimode fiber feed introduces several challenges, one of which is a fundamental limit on how much light can be coupled into a VIPA. In this work, we derive a closed-form expression for the minimum tilt angle of a multimode fiber-fed VIPA required for no etendue coupling loss, and we show that this angle depends solely on the input fiber's etendue, the focal ratio of the injection cylindrical lens, and the VIPA's intrinsic parameters. Moreover, we derive the 2D and 3D etendue that can be coupled into a VIPA, as well as the VIPA's etendue coupling efficiency and total transmission, given a particular configuration. We validate our mathematical models using ray-tracing simulations in Zemax OpticStudio non-sequential mode. Our results provide practical guidance for the design of high-throughput optical systems based on multimode fiber-fed VIPAs.
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All authors Matthew C. H. Leung, Andrew Szentgyorgyi, Colby Jurgenson, David Charbonneau
Quantum Physics
Fault-tolerant quantum computation with static atomic buses
Matteo Bergonzoni, Laura Pecorari, Sam Norrell et al. (+3 more)
Efficient
quantum error correction and fault-tolerant
quantum computing require scalable, high-fidelity long-range connectivity. In neutral-atom
quantum computers, this is commonly achieved through atom transport, but shuttling introduces latency and motional heating that worsen with system size. Here, we introduce a neutral-atom architecture based on static atomic buses, in which auxiliary mediator atoms enable long-range entangling operations without
qubit transport. The architecture naturally supports long-range stabilizer measurements in high-rate LDPC codes and transversal logical gates between neighboring surface-code patches, enabling a modular framework for efficient logical
memories, Clifford computation, and magic-state
distillation. To realize these capabilities, we co-design optimal-control protocols for bus-mediated controlled-Z gates that incorporate both microscopic neutral-atom dynamics and architectural constraints. We obtain smooth bus-mediated gates with fidelities approaching 99.9% and durations of a few hundred nanoseconds by combining time-optimal control with interaction-flatness and robustness constraints. Large-scale simulations of
quantum error correction and logical entangling operations between neighboring surface-code patches predict more than an order-of-magnitude improvement in logical error rates compared with atom-shuttling architectures under realistic noise. The architecture achieves logical gate times of approximately 100 us and
quantum-error-correction cycle times of about 1 ms for code distances d<12. These results establish static atomic buses as a practical alternative to atom shuttling for scalable fault-tolerant neutral-atom
quantum computing.
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All authors Matteo Bergonzoni, Laura Pecorari, Sam Norrell, Cody Poole, Guido Pupillo, Mark Saffman
Astrophysics of Galaxies
Satellite quenching by radio jets of central galaxies in galaxy groups
Yijun Wang, Tao Wang, Dingyi Zhao et al. (+9 more)
Feedback from active
galactic nuclei (AGN) is now recognized as a key component of
galaxy formation models. It plays a central role in regulating the growth and quenching of
galaxies in the center of groups. However, the impact of AGN feedback from central
galaxies on satellite
galaxies remains largely unexplored. Here based on the largest sample to date of
radio AGNs in
galaxy groups (Yang et al. 2007) and a comprehensive consideration of multiple physical parameters that may influence the
star formation of satellite
galaxies, we demonstrate that the quiescent satellite fraction around
radio AGNs is higher than that around normal
galaxies. The most significant enhancement is observed around AGNs with large
radio lobes. These findings demonstrate that the impact of kinetic AGN feedback beyond their host
galaxies to their satellites. These results provide novel insights into the physical origins of some long-standing puzzles in extragalactic astronomy, including, e.g.,
galactic conformity and the strong small-scale clustering of quiescent
galaxies.
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All authors Yijun Wang, Tao Wang, Dingyi Zhao, Yingjie Peng, Ziwen Zhang, Houjun Mo, Feng Yuan, Zhaozhou Li, Lingyu Wang, Yu Qiu, Yangyao Chen, Ke Xu
Quantum Physics
Reducing quantum measurements in qubit-based overlapping grouping methods for quantum energy estimation through better initializations
Isaac L. Huidobro-Meezs and Rodrigo A. Vargas-Hernández
The measurement cost for estimating expectation values of
Hamiltonians is a central bottleneck in variational
quantum algorithms. Grouping strategies significantly reduce this cost, with overlapping techniques as the state of the art. Overlapping grouping methods require i) a non-overlapping grouping of the
Hamiltonian, typically obtained from the Sorted Insertion (SI)
algorithm as initialization, and ii) the construction of covariance dictionaries from approximate wavefunctions to guide the optimization. It was recently shown that different initializations can potentially reduce measurement costs for overlapping methods. Motivated by these findings, we introduce variance-aware SI (VarSI), a family of covariance-informed non-overlapping Pauli grouping heuristics to reduce measurement counts. VarSI grouping leverages the covariance dictionaries, already required by overlapping methods, to construct better non-overlapping groups. We propose three variants: a global greedy grouping insertion rule, a variance-informed SI analog, and a local refinement step initialized from SI or our variance-informed variant. We showcase the use of the VarSI groupings as initialization of overlapping methods using the iterative coefficient-splitting (ICS)
algorithm. Molecular
benchmarks with 130
Hamiltonians demonstrate consistent, non-overlapping measurement improvements over SI of 36–39% and enhanced downstream ICS results when initialized from VarSI groups. We find that the initializations considered here achieve larger reductions of up to 48% for systems whose covariances deviate from idealized cases. Compared to the standard SI initialization, VarSI reaches mean reductions of 10.3–13.5% depending on
qubit mappings and covariance dictionaries used. These results show that non-overlapping grouping remains a consequential design step even when the final
estimator uses overlapping fragments.
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Applied Physics
Synergistic enhancement of Bi2Te3 Sb2Te3 PMMA thermoelectric generators via dithiol assisted conductivity and FEM based geometry optimization
Bejan Hamawandi, Jose F. Serrano Claumarchirant, Adem B. Ergul et al. (+6 more)
In recent decades, thermoelectric (TE) materials have proven to be a complementary source of renewable energy, as they can directly convert waste heat into electrical energy. Energy-efficient, reliable, and scalable synthetic routes for the fabrication of TE materials and their processing into functional devices via low-energy and low-waste routes are necessary for the broader adoption of these materials in various applications. In this work, we report the formulation of hybrid thermoelectric (hTE) inks based on nanostructured Sb2Te3 and Bi2Te3, using PMMA as the
polymer matrix and hexanedithiol (HDT) as the binder. Percolation studies were conducted to determine the optimal film composition, with an 80% nanoparticle content yielding the highest TE performance. Finite element modelling (FEM) was employed to optimize the device geometry, including the cross-sectional area ratio of p- and n-type legs, to maximize power output. Based on these results, a flexible hTEG was fabricated using the optimized ink composition. The device exhibited an output power of 950 nW and a Power Output Density (PoD) of 40.37 nW cm-2 under a 30 K temperature gradient, significantly outperforming previously reported
polymer-based flexible hTEGs incorporating chalcogenides. This study presents a sustainable and effective strategy for developing high-performance hybrid thermoelectric devices through ink formulation, composition optimization, and simulation-guided device design.
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All authors Bejan Hamawandi, Jose F. Serrano Claumarchirant, Adem B. Ergul, Kaspars Pudzs, Inga Pudza, Parva Parsa, Metehan Kirsanli, Oskars Bitmets, Muhammet S.Toprak
General Relativity and Quantum Cosmology
Interacting Holographic Dark Energy in $f(Q)$ Gravity: Cosmological Evolution and Gravitational Wave Signatures
N. Amiriborkhani, Alireza Amani and M. A. Ramzanpour
In this paper, an interactive
Holographic Dark Energy (HDE) model is studied in the framework of modified
gravity \(f(Q)\). By adopting a power parameterization for the Hubble parameter, the field equations are reconstructed and the
evolution of the universe at the background level and tensor perturbations are investigated. Then, using observational data \(H(z)\), the model parameters are constrained and the dynamical behavior of dark energy throughout the history of the universe is analyzed. Also, the study of the
evolution of energy density, pressure and the Equation of State (EoS) parameter of dark energy shows that dark energy in the late universe naturally tends to a region close to the cosmological constant behavior, while in the past it followed a distinct dynamical
evolution. Stability analysis based on the speed of sound also indicates that the model has good classical stability around the present era. In addition, the compatibility of the current values of the relative density parameters of matter and dark energy with the observational constraints confirms the ability of the model to reproduce the main features of the observed universe. Next, the propagation of gravitational waves in the cosmological context of the model is investigated. The results show that the corrections due to \(f(Q)\)
gravity and the interaction between matter and dark energy can affect the
evolution of tensor perturbations and produce signatures distinct from the standard scenario. Overall, the findings of this study indicate that the interactive HDE in the gravitational framework \(f(Q)\) can provide a consistent framework for describing the
cosmic acceleration and studying the cosmological consequences of gravitational waves.
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Chemical Physics
Auditing Haldane Consistency in Reversible Enzyme Kinetics: A Curated Two-Sided Backbone and a Labeled Fold-Error Benchmark
Megan Simons and Jonathan Washburn
Reversible enzyme kinetic constants can be audited through the Haldane relation: the apparent
equilibrium constant implied by the rate law should match biochemical thermodynamics under matched conditions. We use the reciprocal cost $C_{\mathrm{Haldane}}=J(K'_{\mathrm{eq,kin}}/K'_{\mathrm{eq,thermo}})$, with $J(x)=\tfrac12(x+x^{-1})-1=\cosh(\ln x)-1$, as a calibrated, direction-symmetric reporting scale. The score is zero at agreement, penalizes reciprocal over- and underestimates equally, encodes the free-energy discrepancy in $RT$ units, and ranks records identically to $|\Delta\Delta G|$; the contribution is therefore biochemical curation, a reproducible workflow, and fold-error calibration rather than a new ordering. We apply the score to a curated demonstration set and, under prespecified inclusion criteria, assemble a two-sided backbone of twenty-one audited single-study records. Eight genuinely independent tests pair kinetics fit without a thermodynamic prior against separately measured
equilibria; all eight fall within twofold (maximum $C_{\mathrm{Haldane}}=0.069$), although this remains a feasibility demonstration. Across the full backbone, eighteen records fall within twofold and three are flagged. The backbone is concentrated in carbohydrate isomerases and epimerases, so these results are within-family observations. Because real records carry no ground-truth labels, a semi-synthetic
benchmark (twenty-nine within-twofold seeds, $1{,}885$ injected known-error cases) quantifies detectability: AUC $0.784$ ($95\%$ bootstrap CI $0.725$–$0.838$), conditional on the injected error taxonomy and invariant under monotone rescaling of $|\ln x|$. All data, code, protocol, and
benchmark generator are archived for exact reproduction.
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Instrumentation and Detectors
First measurement of flux of the neutron background induced by accelerated neutrinos at the J-PARC facility
Hiroshi Ito, Ryo Shibayama, Chisako Ise et al. (+3 more)
This article reports the measurement of the
neutron background flux accidentally induced by the
neutrino beam at the J-PARC facility in Japan. In particular,
neutrino-
nucleus neutral-current quasi-elastic (NCQE) scattering events, $\nu~(\bar{\nu})+\rm{N}\to\nu~(\bar{\nu})+\rm{N'}$, can be obscured by a massive background of
neutron-
nucleus scattering events. The
neutrons are produced within the materials (such as sand and concrete) located between the beam dump and the experimental area where the detectors are placed. We measured the accidental
neutron events at the J-PARC
neutrino facility using BGO and
liquid scintillation detectors, with a plastic scintillation detector serving as an active veto counter. Based on a
neutrino-mode data set of $2.972 \times 10^{20}$ POT, we observed 88
neutron-induced
recoil proton events within an electron-equivalent
recoil energy range of 0.98-11.60 $\rm MeV_{ee}$, selected via pulse-shape discrimination in the
liquid scintillation detector. Accounting for the detection efficiency and resolution, and through comparison with simulations, the
neutron flux was determined to be$[1.45^{+0.22}_{-0.24}~\rm{(stat.)} \pm 0.55~\rm{(sys.)}] \times 10^{-7}~\rm{cm}^{-2} \rm{s}^{-1}\rm{POT}^{-1}$,assuming an exponential
neutron energy spectrum. This result will contribute to the evaluation of
neutron backgrounds for
neutrino experiments at the J-PARC facility.
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All authors Hiroshi Ito, Ryo Shibayama, Chisako Ise, Akihiro Minamino, Yusuke Koshio, Masaki Ishitsuka
Mathematical Physics · Cross-listed from math.PR
Zhen-Qing Chen, Martin Grothaus and Onno Pfohl
We establish $L^2$-exponential strong ergodicity (strong mixing) with an explicit rate of convergence for a class of degenerate
diffusions with multiplicative noise and with singular drift in both the noisy and noise-free components. This class includes
diffusions with an additional inert drift given by the gradient of a singular potential, as well as singular generalized
stochastic Hamiltonian systems. Cases in which the
diffusion is confined to a proper, bounded or unbounded subset of $\mathbb{R}^{d_1+d_2}$ are included. Concrete examples of admissible potentials are provided. To obtain these results, we use an analytical approach and study the long-time behavior of the strongly continuous contraction
semigroup generated by the formal Kolmogorov backward operator. Using the theory of generalized Dirichlet forms, these objects are then identified with the transition
semigroup and generator of the unique weak solution to the original
stochastic differential equation. The existence and uniqueness of this solution are established under near-minimal conditions.
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Materials Science
First principles study of chalcogen vacancy effect on the optoelectronic and photocatalytic properties of transition metal dichalcogenides monolayers
Tahir Wahab, Antonio Cammarata and Tomas Polcar
In working conditions, chalcogen vacancies spontaneously occur in two-dimensional transition metal dichalcogenides (TMDCs) monolayers, affecting their optoelectronic and photocatalytic properties. To study how chalcogen vacancies affect such properties, we use
quantum mechanical calculations considering prototypical MX$_2$ (M = Mo, W, X = S and Se) TMDCs monolayers. Structural optimisations show that M-X bond lengths about a vacancy are different compared to the bond lengths in the pristine structure. Band structure calculations reveal that the introduction of vacancies produce electronic states about the
Fermi level, hence resulting in the reduction of the band gap. Work function and electrostatic potential calculations show that the introduction of vacancies induce an asymmetry in the electrostatic potential facilitating the charge separation; such feature is absent in a pristine monolayer. All the considered defective structures are capable of performing hydrogen
evolution reaction, while co-catalyst is required to perform oxygen
evolution reaction when used for water splitting. WS$_2$ and WSe$_2$ defective monolayers can serve as an efficient photocatalytic material for reducing CO$_2$ into useful chemical products. The presented results show that vacancy-containing TMDCs monolayers own photocatalytic capabilities compared to the pristine counterparts, thus showing that defective TMD monolayers have prospective applications and should not be regarded as flawed products to be discarded. Finally, the results might constitute guidelines for the experimental synthesis of vacancy-engineered MX$_2$ monolayers for optoelectronic devices and photocatalytic applications.
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Solar and Stellar Astrophysics
The Stellar Observations Network Group (SONG) – A Legacy Archive of Stellar Time-Domain Spectroscopy
M. N. Lund, F. Grundahl, M. S. Fredslund et al. (+41 more)
The
Stellar Observations Network Group (SONG) network has operated for more than a decade, providing long-baseline, high-cadence spectroscopic observations of bright
stars and the Sun. The observations, from 2014 through 2025, constitute a substantial archive of high-resolution spectra and precise radial velocities for a broad range of time-domain
stellar astrophysics. We present an overview of the status, instrumentation, and scientific capabilities of the SONG network, and describe the scope and accessibility of the SONG Data Archive (SODA). We further illustrate the breadth of science enabled by SONG observations, including asteroseismology,
stellar variability studies, binary-
star characterisation, and
exoplanet research. We summarise the operational status and observing strategies of the SONG facilities, describe the available data products and archive infrastructure, and outline procedures for accessing archival observations and proposing new observations within the SONG community framework. The SODA archive currently contains more than 580,000 spectra of 3091
stars obtained with SONG using either iodine-
cell or Thorium-Argon wavelength calibration. The archive spans over a decade and includes extensive time-series data for bright targets across a wide range of
stellar types and variability classes. Access to the archive is available to members of the SONG community, which remains open to new participants who agree to follow the community policies. The SONG archive has developed into a major long-baseline resource for
stellar spectroscopy and radial-velocity time-series analysis. Continued expansion of the archive, together with coordinated observations obtained contemporaneously with TESS and future PLATO observations, is expected to enable new studies of
stellar oscillations, variability, and
exoplanet host
stars through combined radial-velocity and photometric analyses.
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All authors M. N. Lund, F. Grundahl, M. S. Fredslund, P. L. Pallé, S. Simon-Diaz, J. Christensen-Dalsgaard, R. A. Wittenmyer, L. Deng, J. Jackiewicz, H. Kjeldsen, V. Antoci, H. Korhonen, S. H. Albrecht, K. Wang, J. Rudrasingam, R. Handberg, T. R. Bedding, J. L. Rørsted, P. M. Sørensen, D. J. Wright, J. A. Holtzman, J. Klusmeyer, S. Frandsen, E. Weiss, J. Jessen-Hansen, P. Heeren, R. Tronsgaard, T. Arentoft, P. G. Beck, U. G. Jørgensen, A. N. Sørensen, M. I. Andersen, P. Kjærgaard, M. Bizzarro, R. P. Butler, E. Corsaro, R. A. García, D. Stello, S. Murphy, J. Horner, S. Martell, M. J. Martínez González, L. Casagrande, J. Lattanzio
Instrumentation and Methods for Astrophysics
The Habitable Worlds Observatory Technology Development Plan
Matthew Bolcar, Feng Zhao, Paul Scowen et al. (+5 more)
The Habitable Worlds Observatory (HWO) is NASA's next large space
telescope, selected by the 2020 Decadal Survey in Astronomy and Astrophysics to search for and characterize habitable
exoplanets while enabling a broad range of transformative astrophysics. In August 2024, the HWO Technology Maturation Project Office (TMPO) was formed to begin exploring the HWO science, technology, and mission architectures toward a Mission Concept Review (MCR) at the end of the decade. A primary deliverable of this effort is this technology development plan that identifies critical technologies that enable the mission, defines a process for assessing the readiness of those technologies, and outlines a strategy for developing those technologies to a Technology Readiness Level (TRL) of 5 before the MCR. This document covers technologies organized along three tracks: Coronagraph System technologies, Ultra-stable
Telescope System technologies, and High-sensitivity Ultraviolet and Visible Instrumentation technologies. Additional emerging and enhancing technologies are also discussed.
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All authors Matthew Bolcar, Feng Zhao, Paul Scowen, Lee Feinberg, Breann Sitarski, Alice Liu, J. Scott Smith, Josh Abel
Quantum Physics
Anuj Gore, Roopayan Ghosh, Dylan Lewis et al. (+1 more)
Quantum entanglement is a powerful resource for
quantum-enhanced technologies. However, its reliable quantification remains challenging due to the exponential scaling of the
Hilbert space with system size, which renders full state
tomography infeasible. Moreover, experimentally estimating
entanglement typically requires a large number of measurement samples leading to a significant overhead. In this work, we present two models, a feed-forward neural network and an
attention-based model, to accurately predict the bipartite second Renyi from projective measurements of
quantum states. We
benchmark their performance against standard classical shadow
estimators and find that the machine-learning approaches achieve higher accuracy and improved sample efficiency across a range of system sizes. Our results demonstrate the potential of machine learning for scalable and efficient estimation of
quantum correlations.
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All authors Anuj Gore, Roopayan Ghosh, Dylan Lewis, Sougato Bose
Soft Condensed Matter
Shear and crystallization in deformable granular packings: why don't auxetics order?
Joel T. Clemmer, Nicholas W. Hackney and Gary S. Grest
Shear of three-dimensional, highly compressed granular packings is simulated using a bonded particle approach that explicitly resolves elastic deformation. Varying Poisson's ratio $\nu$ produces significant changes in rheology, packing structure, and grain morphology. During flow, conventional systems ($\nu > 0$) readily crystallize while auxetics ($\nu < 0$) resist ordering. This duality reflects the fact that conventional grains develop polyhedral-like facets but conserve volume while auxetics behave oppositely, demonstrating an unexpected interaction between elasticity, geometry, and crystallization.
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Exactly Solvable and Integrable Systems
Analysis of Lie symmetries and traveling wave solutions for the (2+1)-dimensional Boussinesq equation with general nonlinearity
Şeyma Gönül and Cihangir Özemir
In this study, we investigate Lie
symmetries of the (2+1)-dimensional Boussinesq equation, which has been proposed to model the propagation of
gravity waves on the water surface, with particular emphasis on the head-on collision of oblique waves. We consider this equation in a more general form involving an arbitrary function f(u) and establish a complete Lie
symmetry classification with respect to the admissible forms of the nonlinearity. For the canonical equations arising from the classification, we construct reductions to ordinary differential equations by using an optimal system of two-dimensional subalgebras. Furthermore, we examine the exact solutions of the equation and analyze the stability of the traveling wave solutions.
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Materials Science
Magnetic ordering in VI3: a van der Waals material combining vastly different magnetic anisotropies
K. K. Pokhrel, S. Ray, N. Machavcova et al. (+2 more)
Among
magnetic van der Waals materials, the vanadium trihalide family exhibits unique features. In particular, VI3 contains V atoms of two different types, as two energetically close electronic occupations can coexist in real samples. These types show strikingly different
magnetic anisotropy, predicted to differ by more than an order of magnitude. The combination forms a distinctive
magnetic system. VI3 also displays an unusual thickness dependence: the monolayer Curie temperature (TC) is higher than that of the bulk, contrary to the expectation that interlayer coupling reinforces
magnetic order. Using atomistic
spin-dynamics simulations informed by first-principles calculations, we investigate the critical temperature behavior from the combined perspective of single-ion anisotropy and exchange interactions. The strong anisotropy contrast significantly affects thermal stability: increasing the fraction of high-anisotropy sites raises the energy cost of transverse
spin fluctuations and increases the ordering temperature. Furthermore, V-atom inhomogeneity makes the interlayer super-superexchange network spatially nonuniform, creating competing exchange pathways. This weakens coherent interlayer order while preserving robust intralayer
ferromagnetic correlations, thus modifying the bulk-monolayer TC relation. Our model reproduces experimental TC values when the ratio of the two V types is close to 1:1, in agreement with two experimental methods. This supports the coexistence of two V configurations in VI3. The monolayer TC is reproduced with a slightly modified ratio, possibly linked to polaron concentration. The sensitivity of TC to this ratio suggests that the ordering temperature of VI3 can in principle be tuned over a broad range by controlling the relative occupation of the two vanadium configurations.
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All authors K. K. Pokhrel, S. Ray, N. Machavcova, A. Koliogiorgos, K. Carva