Computational Physics · Cross-listed from astro-ph.HE
GenASiS: General Astrophysical Simulation System. II. Self-gravitating Baryonic Matter
Christian Y. Cardall, Reuben D. Budiardja, R. Daniel Murphy et al. (+1 more)
GenASiS (General Astrophysical Simulation System) is a code being developed initially and primarily, though not exclusively, for the simulation of core-collapse
supernovae on the world's leading capability supercomputers. This paper – the second in a series – documents capabilities for Newtonian self-gravitating fluid dynamics, including tabulated microphysical equations of state treating
nuclei and
nuclear matter (`baryonic matter'). Computation of the gravitational potential of a spheroid, and simulation of the gravitational collapse of
dust and of an ideal fluid, provide tests of self-gravitation against known solutions. In multidimensional computations of the adiabatic collapse, bounce, and explosion of spherically symmetric pre-
supernova progenitors – which we propose become a standard
benchmark for code comparisons – we find that the explosions are
prompt and remain spherically symmetric (as expected), with an average shock expansion speed and total kinetic energy that are inversely correlated with the progenitor mass at the onset of collapse and the compactness parameter.
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All authors Christian Y. Cardall, Reuben D. Budiardja, R. Daniel Murphy, Eirik Endeve
General Physics
Statistical physics on Euclidean Snyder space: connections with the GUP and cosmological implications
Boris Ivetić and Giuseppe Gaetano Luciano
We develop a systematic formulation of statistical mechanics on Euclidean Snyder space, where noncommutativity is geometrically encoded in the
curvature of momentum space. Adopting a realization independent approach based on momentum-space invariants, we derive modified partition functions and thermodynamic quantities for systems obeying Maxwell-Boltzmann, Bose-Einstein and
Fermi-Dirac statistics in both non-relativistic and ultrarelativistic regimes. We show that momentum-space
curvature induces temperature-dependent corrections that suppress the energy,
entropy and energy density with respect to their standard counterparts. We apply these results to early-Universe cosmology, deriving the corresponding corrections to the Friedmann equations driven by the modified energy density of radiation. Using Big Bang Nucleosynthesis as a precision probe, we derive bounds on the Snyder deformation parameter and, via a phenomenological mapping, on the Generalized Uncerainty Principle (GUP) parameter, providing one of the most stringent cosmological and astrophysical constraints currently available. Our analysis demonstrates that high-energy cosmological processes provide a predictive arena for testing momentum-space
curvature and noncommutative geometry effects.
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Chemical Physics
The Illusion of Simplicity: The Dramatic Failure of Koopmans Theorem for Antioxidants in Solvents – The Ascorbic Acid Paradigm
Ioan Bâldea
Antioxidants operate in biological environments where solvent effects dramatically alter their redox properties. Using ascorbic acid (vitamin C) as a paradigmatic example, we present a comprehensive
quantum-chemical investigation of its global chemical reactivity indices – ionization potential, electron affinity, HOMO-LUMO gap, hardness, softness, electronegativity, electrophilicity, and electrodonating/accepting powers – computed at the compound chemistry CBS-QB3 and various DFT levels in vacuo and across six solvents. The results demonstrate that solvation stabilizes charged species so strongly that reactivity indices shift by several electronvolts, following a roughly Born-like dependence on dielectric constant. Most importantly, we show unequivocally that Koopmans'
theorem, often used to estimate these indices from orbital energies, fails catastrophically in solution: it predicts solvent-independent values that are qualitatively and quantitatively wrong, missing the essential physics of dielectric screening and
geometric relaxation. We therefore conclude that Koopmans'
theorem must be abandoned for antioxidant studies in condensed phases; adiabatic calculations with solvent are mandatory for meaningful predictions.
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Fluid Dynamics
Elucidating Three-Dimensional Coherent Structures in a Multi-Stream Jet
Mitesh Thakor, Datta V Gaitonde and Yiyang Sun
Nominal two-dimensional (2D) shear layers have been studied extensively, and their principal dynamics are well understood. In practical configurations, however, the behavior of such shear layers is affected by proximal surfaces. In this study, we investigate three-dimensional (3D) coherent structures developing downstream of a relatively thick splitter plate in a realistic nozzle featuring sidewalls, an upper boundary formed by a single expansion ramp, and a lower boundary defined by a protruding deck. As a result, in addition to the primary splitter plate shear layer (SPSL) arising from mixing between the core and bypass streams, the flow contains upper (USL) and lower (LSL) shear layers with the ambient. Large-eddy simulation data are analyzed to characterize the unsteady flow dynamics, while the mean flow provides insight into the underlying amplification mechanisms. Spectral proper orthogonal decomposition reveals a clear separation of broadband and tonal dynamics across frequency bands. The broadband low-frequency modes are highly 3D and originate in the USL and LSL. In contrast, tonal high-frequency content is associated with a 2D instability in the SPSL. Both the broadband and tonal signatures also appear in the nonlinear energy transfer mechanisms. Triglobal resolvent analysis further clarifies the amplification mechanisms within the USL and LSL. Low-frequency response modes are excited by forcing localized near the nozzle geometry and are governed by 3D Kelvin-Helmholtz dynamics. The low-frequency streamwise
vortices generated at the nozzle corners drive the axis-switching behavior characteristic of rectangular jets. Wavemaker analysis further demonstrates that these corner
vortices are part of self-sustaining low-frequency dynamics.
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Computational Physics
Physics Informed Differentiable Solvers for Learning Parametric Solution Manifolds in Heterogeneous Physical Systems
Milad Panahi, Giovanni Michele Porta, Monica Riva et al. (+1 more)
Learning the full family of solutions to parameterized partial differential equations (PDEs) is a central challenge to our ability to model the behavior of heterogeneous systems, with a variety of fundamental and application-oriented implications in fields such as hydrogeology where system properties exhibit significant (and often uncertain) spatial heterogeneity. We address this by reformulating a Physics-Informed Neural Network (PINN) as a differentiable solver that learns the continuous solution
manifold for steady-state Darcy flow. Our framework requires only a single training run, circumventing the need for costly re-training for each new parameter instance. Its versatility is demonstrated through two representations of spatially heterogeneous hydraulic conductivity fields: a direct analytical form and a novel data-driven formulation resting on an autoencoder to create a low-dimensional latent encoding. A key innovation is the integration of the differentiable decoder into the physics-informed loss function, enabling on-the-fly reconstruction of complex conductivity fields via automatic differentiation. The approach yields accurate, mass-conserving flow solutions and supports efficient uncertainty quantification, providing a general methodology for physics-constrained data-driven modeling of heterogeneous systems.
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All authors Milad Panahi, Giovanni Michele Porta, Monica Riva, Alberto Guadagnini
Chemical Physics
Accuracy and Efficiency Benchmarks of Pretrained Machine Learning Potentials for Molecular Simulations
Peter Eastman, Evan Pretti and Thomas E. Markland
The rapid development of pretrained Machine Learning Interatomic Potentials (MLIPs) that cover a wide range of molecular species has made it challenging to select the best model for a given application. We
benchmark 15 pretrained MLIPs, evaluating each one on accuracy, speed,
memory use, and ability to produce stable simulations. This provides an objective basis for practitioners to select the most appropriate MLIP for their own simulations, and offers insight into which factors most strongly influence model accuracy. We find that the number of model parameters and the size of the training set are both strongly correlated with accuracy, but observe no benefit from including explicit Coulomb energy terms. Speed and
memory use are determined as much by the model architecture as by the size of the model.
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Optics
Single-View Holographic Volumetric 3D Printing with Coupled Differentiable Wave-Optical and Photochemical Optimization
Felix Wechsler, Riccardo Rizzo and Christophe Moser
Volumetric additive manufacturing promises near-instantaneous fabrication of 3D objects, yet achieving high fidelity at the micro-scale remains challenging due to the complex interplay between optical diffraction and chemical effects. We present Single-View
Holographic Volumetric Additive Manufacturing (SHVAM), a mechanically static system that shapes volumetric dose distributions using time-multiplexed, phase-only holograms projected from a single optical axis. To achieve high resolution with SHVAM, we formulate hologram synthesis as a coupled inverse problem, integrating a differentiable wave-optical forward model with a simplified photochemical model that explicitly captures inhibitor
diffusion and non-linear dose response. Optimizing hologram sequences under these coupled constraints allows us to pre-compensate for chemical blur, yielding higher print fidelity than optical-only optimization. We demonstrate the efficacy of SHVAM by fabricating simple 2D and 3D structures with lateral feature sizes of approximately \SI{10}{\micro\meter} within a $\SI{0.8}{\milli\meter} \times \SI{0.8}{\milli\meter} \times \SI{3}{\milli\meter}$ volume in seconds.
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Physics and Society
National Quantum Strategies: A Data-Driven Approach to Understanding the Quantum Ecosystem
Simon Richard Goorney, Emre Aslan, Aleksandrs Baskakovs et al. (+2 more)
As
quantum technologies (QT) move from foundational research toward industrial and societal deployment, national strategies have become critical instruments for shaping the future of this emerging field. In this study, we conduct the first large-scale, data-driven analysis of 62 national
quantum strategic documents (QSDs) from 20 countries. Using AI-based natural
language processing (topic modeling), we identify 12 topics present in the text, ranging from technical development areas to transversal aspects such as workforce development and governance. Temporal analysis reveals a distinct shift in policy discourse toward applications of QT and commercialisation, and relatively away from basic science. Our findings highlight the increasing diversification of the QT field, and contribute to the growing area of
quantum policy studies. We advocate for more AI and data-driven analyses of the
quantum ecosystem, to work toward a scalable framework for understanding the technological and societal challenges of the second
quantum revolution.
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All authors Simon Richard Goorney, Emre Aslan, Aleksandrs Baskakovs, Borja Muñoz, Jacob Sherson
Atomic Physics
Bichromatic Tweezers for Qudit Quantum Computing in ${}^{87}$Sr
Enrique A. Segura Carrillo, Eric J. Meier and Michael J. Martin
Neutral atoms have become a competitive platform for
quantum metrology, simulation, sensing, and computing. Current magic trapping techniques are insufficient to engineer magic trapping conditions for qudits encoded in hyperfine states with $J \neq 0$, compromising qudit coherence. In this paper we propose a scheme to engineer magic trapping conditions for qudits via bichromatic tweezers. We show it is possible to suppress differential light shifts across all
magnetic sublevels of the $5s5p$ $\mathrm{^{3}P_2}$ state by using two carefully chosen wavelengths (with comparable tensor light shift magnitude and opposite sign) at an appropriate intensity ratio, thus suppressing light-shift induced dephasing, enabling scalar magic conditions between the ground state and $5s5p$ $\mathrm{^{3}P_2}$, and tensor magic conditions for qudits encoded within it. Furthermore, this technique enables robust operation at the tensor magic angle 54.7$^\circ$ with linear trap polarization via reduced sensitivity to uncertainty in experimental parameters. We expect this technique to enable new loading protocols, enhance cooling efficiency, and enhance
nuclear spins' coherence times, thus facilitating qudit-based
quantum computing in ${}^{87}$Sr in the $5s5p$ $\mathrm{^{3}P_2}$
manifold.
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Classical Physics · Cross-listed from gr-qc
Does Gravity Care About Electric Charge? A Minimalist Model and Experimental Test
Renato Vieira dos Santos
Does
gravity care about electric charge? Precision tests of the weak equivalence principle achieve remarkable sensitivity but deliberately minimize electric charge on test masses, leaving this fundamental question experimentally open. We present a minimalist framework coupling electromagnetism to linearized
gravity through conservation of a complex charge-mass current, predicting charge-dependent violations $\Delta a/g = \kappa(q/m)$. Remarkably, this prediction occupies unexplored experimental territory precisely because precision
gravity tests avoid charge variation. We identify this as a significant gap and propose a modified torsion balance experiment where $q/m$ is treated as a controlled variable. Such an experiment could test whether gravitational acceleration depends on electric charge, probing physics in genuinely new parameter space. This work exemplifies how theoretical minimalism can reveal overlooked opportunities in fundamental physics.
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Optics · Cross-listed from cond-mat.quant-gas
Controlled Switching of Bose-Einstein Condensation in a Mixture of Two Species of Polaritons
Hassan Alnatah, Shuang Liang, Qiaochu Wan et al. (+5 more)
We report temperature-dependent switching between lower and upper polariton condensation in a GaAs/AlGaAs microcavity when both of these species have comparable populations in a mixture. Using angle-resolved photoluminescence, we observe that at low temperatures, condensation occurs in the lower polariton branch, while at elevated temperatures, the upper polariton branch can become favored. At an intermediate temperature, we observe instability in the condensate formation, characterized by metastable correlations of the fluctuations in intensity and linewidth of the lower and upper polariton branches.
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All authors Hassan Alnatah, Shuang Liang, Qiaochu Wan, Jonathan Beaumariage, Kirk Baldwin, Adbhut Gupta, Loren N. Pfeiffer, David W. Snoke
Instrumentation and Detectors
Performance of a SuperCDMS HVeV Detector with Sub-eV Energy Resolution and Single Charge-sensitivity
Kyle Kennard, Aditi Pradeep, Mason Buchanan et al. (+41 more)
We present a detailed characterization of a new generation of athermal-
phonon single-charge sensitive Si HVeV detectors, the best of which achieved 589~meV~$\pm$~5~meV baseline resolution. Our sub-eV energy resolution enables precise measurements of single-
photon events and reveal consistent energy losses of 0.92~eV~$\pm$~0.02~eV per charge excitation across two facilities. We demonstrate that the noise for these detectors is well described using a standard Transition Edge Sensor noise model. We also measure a nominal
phonon collection efficiency of 45%~$\pm$~3%~(stat.)~$\pm$~6%~(syst.) in the best performing device, establishing these detectors as the most efficient athermal
phonon detectors to date, limited only by intrinsic limitations of quasiparticle generation.
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All authors Kyle Kennard, Aditi Pradeep, Mason Buchanan, Hope Fu, Aviv Simchony, Qihua Wang, Emanuele Michielin, Taylor Aralis, Elspeth Cudmore, Priscilla Cushman, Miriam Diamond, Enectali Figueroa-Feliciano, Caleb Fink, Simon Harms, Bruce A. Hines, Ziqing Hong, Martin E. Huber, Andrew Kubik, Noah Kurinsky, Rupak Mahapatra, Valentina Novati, Lekhraj Pandey, Pratyush K. Patel, Weigeng Peng, Mark Platt, Ry Pressman-Cyna, Wolfgang Rau, Runze Ren, Tyler Reynolds, James Ryan, Tarek Saab, David Sadek, Benjamin Schmidt, Zoë Smith, Sidney Stevens, Kelly Stifter, Matthew Stukel, Julius Viol, Yongqi Wang, Matthew James Wilson, Betty Young, Stefan Zatschler, Hazal Zenger, Ariel Zuñiga-Reyes
Computational Physics
Collective Rabi-driven vibrational activation in molecular polaritons
Carlos M. Bustamante, Franco P. Bonafé, Richard Richardson et al. (+5 more)
Molecular polaritons arise from electronic or vibrational strong coupling (ESC and VSC) with confined electromagnetic fields. While these have been widely studied, the influence of electron-
nuclear dynamics in driven cavities remains largely unknown. Here, we report a previously unrecognized mechanism of vibrational activation that emerges under collective ESC in driven optical cavities. Using simulations that self-consistently combine Maxwell's equations with
quantum molecular dynamics, we show that collective electronic Rabi oscillations coherently drive
nuclear motion. This effect is captured using both vibrational wave-packet dynamics in a minimal two-level model and atomistic simulations based on time-dependent density-functional tight-binding theory. Vibrational activation depends non-monotonically on the Rabi frequency and is maximized when the collective polaritonic splitting resonates with a molecular vibrational mode. The mechanism exhibits features consistent with a stimulated Raman-like relaxation mechanism. Our predictions are robust under realistic cavity conditions and provide the conditions in which they could be verified experimentally.
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All authors Carlos M. Bustamante, Franco P. Bonafé, Richard Richardson, Michael Ruggenthaler, Wenxiang Ying, Abraham Nitzan, Maxim Sukharev, Angel Rubio
Instrumentation and Detectors
VUV Reflectance Measurements for Materials Relevant to Argon and Xenon Experiments
J. Soto-Oton, H. Amar, A. Cervera et al. (+1 more)
Accurate knowledge of material reflectance in the
vacuum ultraviolet (VUV) range is crucial for optimizing
photon detection in noble gas detectors such as DUNE. Despite its importance, reflectance values for detector materials in the VUV region remain poorly characterized, with literature values showing significant variation depending on surface termination and finish. We present an angular-resolved reflectance measurement system developed at IFIC that operates in a gaseous argon atmosphere, enabling realistic measurements of detector materials under controlled conditions. The setup couples a deuterium lamp to a monochromator and employs a motorized PMT rotating around the sample to measure reflected light distributions across a wide angular range. We have characterized two key DUNE materials – aluminum field cage profiles and stainless steel cryostat membranes – in both the UV-VIS (300-500 nm) and VUV (128-200 nm) ranges. In the UV-VIS region, we confirm literature values of approximately 60% reflectance for aluminum and 40% for stainless steel. Preliminary VUV measurements at 45{\deg} angle of incidence yield reflectance values of 10-15% for both materials, significantly lower than their UV-VIS counterparts. The reflected light distributions exhibit a mixed character between specular and diffuse reflection. These results have direct implications for detector simulations and light yield predictions in next-generation experiments.
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All authors J. Soto-Oton, H. Amar, A. Cervera, A. Roche
Fluid Dynamics
A Study of Improved Limiter Formulations for Second-Order Finite Volume Schemes Applied to Unstructured Grids
Frederico Bolsoni Oliveira and João Luiz F. Azevedo
A general, compact way of achieving second-order in finite-volume numerical methods is to perform a MUSCL-like, piecewise linear reconstruction of flow properties at each
cell interface. To avoid the surge of spurious oscillations in the discrete solution, a limiter function is commonly employed. This strategy, however, can add a series of drawbacks to the overall numerical scheme. The present paper investigates this behavior by considering three different limiter formulations in the context of a second-order, finite volume scheme for the simulation of steady, turbulent flows on unstructured meshes. Three limiter formulations are considered: the original Venkatakrishnan limiter, Wang's modification to the Venkatakrishnan limiter and Nishikawa's recently introduced R3 limiter. Three different configurations of the fully-developed, two-dimensional, transonic NACA 0012 airfoil are analyzed, configured with different angles of attack and similar freestream properties. The gas dynamics are modeled using the Reynolds-averaged Navier-Stokes (RANS) equations, where the negative Spalart-Allmaras
turbulence model is used to solve the closure problem. All limiters are shown to yield similar results for all configurations of this case, although with different dissipative characteristics, provided their control constants are used within appropriate intervals. The presented numerical results are in good agreement with experimental data available in the literature.
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Popular Physics
A Brief Guide to Science Communication
Donald W. Lincoln
An introduction into techniques that lead to effective communication techniques of scientific concepts to general audiences.
Optics
Active learning for photonic crystals
Ryan Lopez, Charlotte Loh, Rumen Dangovski et al. (+1 more)
Active learning for photonic
crystals explores the integration of analytic approximate
Bayesian last layer neural networks (LL-BNNs) with uncertainty-driven sample selection to accelerate photonic band gap prediction. We employ an analytic LL-BNN formulation, corresponding to the infinite Monte Carlo sample limit, to obtain uncertainty estimates that are strongly correlated with the true predictive error on unlabeled candidate structures. These uncertainty scores drive an active learning strategy that prioritizes the most informative simulations during training. Applied to the task of predicting band gap sizes in two-dimensional, two-tone photonic
crystals, our approach achieves up to a 2.7x reduction on average in required training data compared to a random sampling baseline while maintaining predictive accuracy. The efficiency gains arise from concentrating computational resources on high uncertainty regions of the design space rather than sampling uniformly. Given the substantial cost of full band structure simulations, especially in three dimensions, this data efficiency enables rapid and scalable surrogate modeling. Our results suggest that analytic LL-BNN based active learning can substantially accelerate topological optimization and inverse design workflows for photonic
crystals, and more broadly, offers a general framework for data efficient regression across scientific machine learning domains.
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All authors Ryan Lopez, Charlotte Loh, Rumen Dangovski, Marin Soljačić
Atomic Physics · Cross-listed from quant-ph
Experimental observation of conformal field theory spectra
Xiangkai Sun, Yuan Le, Stephen Naus et al. (+6 more)
Conformal field theories (CFTs) feature prominently in high-energy physics, statistical mechanics, and condensed matter. For example, CFTs govern emergent universal properties of systems tuned to
quantum phase transitions, including their
entanglement, correlations, and low-energy excitation spectra. Much of the rich structure predicted by CFTs nevertheless remains unobserved in experiment. Here we directly observe the energy excitation spectra of emergent CFTs at
quantum phase transitions – recovering universal energy ratios characteristic of the underlying field theories. Specifically, we develop and implement a modulation technique to resolve a Rydberg chain's finite-size spectra, variably tuned to
quantum phase transitions described by either Ising or tricritical Ising CFTs. We also employ local control to distinguish parities of excitations under reflection and, in the tricritical Ising chain, to induce transitions between distinct CFT spectra associated with changing boundary conditions. By utilizing a variant of the modulation technique, we furthermore study the dynamical structure factor of the critical system, which is closely related to the correlation of an underlying Ising conformal field. Our work not only probes the emergence of CFT features in a
quantum simulator, but also provides a technique for diagnosing a priori unknown universality classes in future experiments.
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All authors Xiangkai Sun, Yuan Le, Stephen Naus, Richard Bing-Shiun Tsai, Lewis R. B. Picard, Sara Murciano, Michael Knap, Jason Alicea, Manuel Endres
Applied Physics · Cross-listed from quant-ph
Engineering Near-Infrared Two-Level Systems in Confined Alkali Vapors
Gilad Orr, Golan Ben-Ari and Eliran Talker
We combined experimental and theoretical investigations of an effective two-level atomic system operating in the near-infrared telecom wavelength regime, realized using hot rubidium vapor confined within a sub-micron-thick
cell. In this strongly confined geometry, atomic coherence is profoundly influenced by wall-induced relaxation arising from frequent atom-surface collisions. By analyzing both absorption and fluorescence spectra, we demonstrate that the optical response is dominated by a closed cycling transition, which effectively isolates the atomic dynamics to a two-level configuration despite the presence of multiple hyperfine states. This confinement-induced selection suppresses optical pumping into uncoupled states and enables robust, controllable light-matter interaction at telecom wavelengths within a miniature atomic platform. Our results establish a practical route to realizing near-infrared atomic two-level systems in compact vapor-
cell devices, opening new opportunities for integrated
quantum photonic technologies, including on-chip
quantum memories, telecom-band frequency references, and scalable
quantum information processing.
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Instrumentation and Detectors
A First Demonstration of the SQUAT Detector Architecture: Direct Measurement of Resonator-Free Charge-Sensitive Transmons
H. Magoon, T. Aralis, T. Dyson et al. (+18 more)
The Superconducting Quasiparticle-Amplifying Transmon (SQUAT) is a new sensor architecture for THz (meV) detection based on a weakly charge-sensitive transmon directly coupled to a transmission line. In such devices, energy depositions break Cooper pairs in the
qubit capacitor islands, generating quasiparticles. Quasiparticles that tunnel across the Josephson junction change the transmon
qubit parity, generating a measurable signal. In this paper, we present the design of first-generation SQUATs and demonstrate an architecture validation. We summarize initial characterization measurements made with prototype devices, comment on background sources that influence the observed parity-switching rate, and present experimental results showing simultaneous detection of charge and quasiparticle signals using aluminum-based SQUATs.
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All authors H. Magoon, T. Aralis, T. Dyson, J. Anczarski, D. Baxter, G. Bratrud, R. Carpenter, S. Condon, A. Droster, E. Figueroa-Feliciano, C.W. Fink, S. Harvey, A. Simchony, Z.J. Smith, S. Stevens, N. Tabassum, B.A. Young, C.P. Salemi, K. Stifter, D.I. Schuster, N.A. Kurinsky
Instrumentation and Detectors
Probing dark matter interactions with a RES-NOVA prototype cryogenic detector
D. Alloni, G. Benato, P. Carniti et al. (+44 more)
We report on the operation of a 13 g PbWO$_4$
crystal, grown from archaeological Pb and operated as a cryogenic calorimeter in an underground environment. Read out with a Ge thermistor, the detector achieves a low energy threshold and, for the first time, enables the derivation of a dark matter exclusion limit using PbWO$_4$ as target material, for both
spin-dependent interactions on
neutrons and
spin-independent interactions. Although limited in mass and not representative of the final RES-NOVA detector design, this prototype demonstrates effective control of mechanical vibrations and low-energy noise in a cryogenic system, which is a key requirement for rare-event searches. The experiment therefore provides a proof of principle for the RES-NOVA detection concept, validating the use of archaeological Pb-based PbWO$_4$
crystals, low-background operation, and robust data-analysis procedures. These results establish a solid technological and methodological foundation for future RES-NOVA detectors employing larger target masses and advanced thermal readout technologies.
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All authors D. Alloni, G. Benato, P. Carniti, M. Cataldo, L. Chen, M. Clemenza, M. Consonni, G. Croci, I. Dafinei, F.A. Danevich, C. de Vecchi, D. Di Martino, E. Di Stefano, N. Ferreiro Iachellini, F. Ferroni, F. Filippini, S. Ghislandi, A. Giachero, L. Gironi, C. Gotti, D.L. Helis, D.V. Kasperovych, V.V. Kobychev, G. Marcucci, A. Melchiorre, A. Menegolli, S. Nisi, M. Musa, L. Pagnanini, L. Pattavina, G. Pessina, S. Pirro, S. Pozzi, M.C. Prata, A. Puiu, S. Quitadamo, M.P. Riccardi, M. Ricci, M. Rossella, R. Rossini, E. Sala, F. Saliu, A. Salvini, V.I. Tretyak, L. Trombetta, D. Trotta, H. Yuan
History and Philosophy of Physics
Recovering Einstein Mature View of Gravitation: A Dynamical Reconstruction Grounded in the Equivalence Principle
Jaume de Haro and Emilio Elizalde
The historical and conceptual foundations of General Relativity are revisited, putting the main focus on the physical meaning of the invariant ds, the Equivalence Principle, and the precise interpretation of spacetime geometry. It is argued that Albert Einstein initially sought a dynamical formulation in which ds encoded the gravitational effects, without invoking
curvature as a physical entity. The now more familiar geometrical interpretation (identifying gravitation with spacetime
curvature) gradually emerged through his collaboration with Marcel Grossmann and the adoption of the
Ricci tensor in 1915. Anyhow, in his 1920 Leiden lecture, Einstein explicitly reinterpreted spacetime geometry as the state of a physical medium (an ether endowed with metrical properties but devoid of mechanical substance) thereby actually rejecting geometry as an independent ontological reality. Building upon this mature view, gravitation is reconstructed from the Weak Equivalence Principle, understood as the exact compensation between inertial and gravitational forces acting on a body under a uniform gravitational field. From this fundamental principle, together with an extension of Fermat Principle to massive objects, the invariant ds is obtained, first in the static case, where the gravitational potential modifies the flow of proper time. Then, by applying the Lorentz transformation to this static invariant, its general form is derived for the case of matter in motion. The resulting invariant reproduces the relativistic form of Newton second law in proper time and coincides with the weak field limit of General Relativity in the harmonic gauge.
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Chemical Physics
Electron Transfer, Diabatic Couplings and Vibronic Energy Gaps in a Phase Space Electronic Structure Framework
Zain Zaidi, Xuezhi Bian and Joseph E. Subotnik
We investigate the well-known Shin-Metiu model for an electronic crossing, using both a standard Born-Huang (BH) framework and a novel phase space (PS) electronic
Hamiltonian framework. We show that as long as we are not in the strongly nonadiabatic region, a phase space framework can obtain a relative error in vibrational energy gap and other vibronic
matrix elements that are consistently one order of magnitude smaller than what is found within a BH framework. In line with recent results showing that dynamics on one phase space surface can outperform dynamics on one Born-Oppenheimer surface, our results indicate that the same advantages should largely hold for curve crossings and dynamics on two or a handful of electronic surfaces, from which several implications can be surmised as far as the possibility of
spin-dependent electron transfer dynamics.
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Atomic Physics · Cross-listed from cond-mat.quant-gas
Universal non-Gaussian order parameter statistics in 2D superfluids
Abel Beregi, En Chang, Erik Rydow et al. (+2 more)
Fluctuations are an intrinsic feature of many-body systems, and their full statistical distributions reveal a wealth of information about the underlying physics. Of particular interest are non-Gaussian, extreme-value statistics that arise when nontrivial correlations and criticality dominate over the central limit
theorem. Strikingly, in two-dimensional (2D)
quantum fluids, such effects have been predicted to manifest in the order parameter distribution in the Berezinskii-Kosterlitz-Thouless (BKT) superfluid phase, which approaches a universal extreme-value form in the low-temperature limit. Here, we measure the order parameter statistics of 2D Bose gases across the BKT critical point using matter-wave interferometry. This allows us to confirm the predicted convergence of the observed statistics to a universal Gumbel distribution at low temperatures, to the 0.1% level of the probability density. Furthermore, the intrinsic precision of the atom interferometer allows the robust extraction of higher-moment observables such as skewness and kurtosis; in particular, we report direct measurements of the Binder cumulant which allows us to precisely identify the onset of the phase transition. Extending this approach to the investigation of non-
equilibrium systems, we probe
vortex unbinding dynamics following a quench across the BKT critical point and identify parameter-independent scaling behaviour of higher moments.
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All authors Abel Beregi, En Chang, Erik Rydow, Christopher J. Foot, Shinichi Sunami
Chemical Physics
Pushing the limits of unconstrained machine-learned interatomic potentials
Filippo Bigi, Paolo Pegolo, Arslan Mazitov et al. (+2 more)
Machine-learned interatomic potentials (MLIPs) are increasingly used to replace computationally demanding electronic-structure calculations to model matter at the atomic scale. The most commonly used model architectures are constrained to fulfill a number of physical laws exactly, from
geometric symmetries to energy conservation. Evidence is mounting that relaxing some of these constraints can be beneficial to the efficiency and (somewhat surprisingly) accuracy of MLIPs, even though care should be taken to avoid qualitative failures associated with the breaking of physical
symmetries. Given the recent trend of scaling up models to larger numbers of parameters and training samples, a very important question is how unconstrained MLIPs behave in this limit. Here we investigate this issue, showing that – when trained on large
datasets – unconstrained models can be superior in accuracy and speed when compared to physically constrained models. We assess these models both in terms of
benchmark accuracy and in terms of usability in practical scenarios, focusing on static simulation workflows such as geometry optimization and
lattice dynamics. We conclude that accurate unconstrained models can be applied with confidence, especially since simple inference-time modifications can be used to recover observables that are consistent with the relevant physical
symmetries.
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All authors Filippo Bigi, Paolo Pegolo, Arslan Mazitov, Jonathan Schmidt, Michele Ceriotti
Physics and Society
Engineering polarization: How contradictory stimulation systematically undermines political moderation
Renato Vieira dos Santos
Political moderation, a key attractor in democratic systems, proves highly fragile under realistic information conditions. We develop a
stochastic model of opinion dynamics to analyze how noise and differential susceptibility reshape the political spectrum. Extending Marvel et al.'s deterministic framework, we incorporate
stochastic media influence $\zeta(t)$ and neuropolitically-grounded sensitivity differences ($\sigma_y > \sigma_x$). Analysis reveals the moderate population – stable in deterministic models – undergoes catastrophic collapse under
stochastic forcing. This occurs through an effective deradicalization asymmetry ($u_{B}^{\text{eff}} = u + \sigma_y^2/2 > u_{A}^{\text{eff}}$) that drives conservatives to extinction, eliminating cross-cutting interactions that sustain moderates. The system exhibits a phase transition from multi-stable coexistence to liberal dominance, demonstrating how information flow architecture – independent of content – systematically dismantles the political center. Our findings reveal moderation as an emergent property highly vulnerable to
stochastic perturbations in complex social systems.
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Biological Physics
In vitro binding energies capture Klf4 occupancy across the human genome
Anne Schwager, Jonas Neipel, Yahor Savich et al. (+4 more)
Transcription factors (TFs) regulate gene expression by binding to specific genomic loci determined by DNA sequence. Their sequence specificity is commonly summarized by a consensus binding motif. However, eukaryotic genomes contain billions of low-affinity DNA sequences to which TFs associate with a sequence-dependent binding energy. We currently lack insight into how the genomic sequence defines this spectrum of binding energies and the resulting pattern of TF localization. Here, we set out to obtain a quantitative understanding of sequence-dependent TF binding to both motif and non-motif sequences. We achieve this by first pursuing accurate measurements of physical binding energies of the human TF Klf4 to a library of short DNA sequences in a fluorescence-anisotropy-based bulk competitive binding assay. Second, we show that the highly non-linear sequence dependence of Klf4 binding energies can be captured by combining a linear model of binding energies with an Ising model of the coupled recognition of nucleotides by a TF. We find that this statistical mechanics model parametrized by our in vitro measurements captures Klf4 binding patterns on individual long DNA molecules stretched in the optical tweezer, and is predictive for Klf4 occupancy across the entire human genome without additional fit parameters.
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All authors Anne Schwager, Jonas Neipel, Yahor Savich, Douglas Diehl, Frank Jülicher, Anthony A. Hyman, Stephan W. Grill
Physics and Society · Cross-listed from cond-mat.stat-mech
Random Walks Across Dimensions: Exploring Simplicial Complexes
Diego Febbe, Duccio Fanelli and Timoteo Carletti
We introduce a novel operator to describe a random walk process on a simplicial complex. Walkers are allowed to wonder across simplices of various dimensions, bridging nodes to edges, and edges to triangles, via a nested organization that hierarchically extends to higher structures of arbitrary large, but finite, dimension. The asymptotic distribution of the walkers provides a natural ranking to gauge the relative importance of higher order simplices. Optimal search strategies in presence of
stochastic teleportation are addressed and the peculiar interplay of noise with higher order structures unraveled.
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Geophysics
Physics-Informed Neural Networks for Viscoacoustic Wave Propagation: Forward Modelling, Inversion and Discretization Sensitivity
Chaohua Liang, Xingliang Peng and Jun Matsushima
Seismic wave forward and inverse modeling are fundamental tools for subsurface imaging and geological hazard assessment. Conventional grid-based numerical methods, such as finite-difference and finite-element approaches, often require dense discretization and repeated forward simulations, leading to high computational cost in inverse problems. Although deep learning has shown promise in seismic applications, its performance is commonly limited by the need for large labeled
datasets and weak enforcement of physical constraints. In this study, we propose a unified physics-informed neural network (PINN) framework for forward modeling and parameter inversion of viscoacoustic wave propagation. By
embedding the viscoacoustic wave equation into the learning process, the proposed framework accurately reproduces wavefields, attenuation, and phase characteristics, while enabling the simultaneous inversion of velocity and attenuation parameters from temporally sparse observations. Numerical experiments demonstrate that the PINN approach achieves stable and reliable accuracy compared with finite-difference solutions, while exhibiting reduced sensitivity to spatial discretization. These results highlight the potential of PINNs as a data-efficient and physically consistent alternative for high-resolution seismic modeling and inversion in attenuative media.
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