Geophysics
Effects of Varying Incident Wave Inclination and Azimuthal Angles on Multi-Dimensional Ground Response Analyses at the Delaney Park Downhole Array Site
Nishkarsha Dawadi and Brady R. Cox
Even when large-scale, site-specific three-dimensional (3D) subsurface models are used to represent spatial variability, multi-dimensional ground response analyses (GRAs) at downhole array sites continue to exhibit amplitude discrepancies between simulated theoretical transfer functions (TTFs) and recorded empirical transfer functions (ETFs), with ETFs at the Delaney Park Downhole Array (DPDA) showing notably lower amplitudes at the fundamental frequency (f0). This discrepancy suggests greater apparent attenuation from wave scattering and destructive interference than is currently captured in multi-dimensional GRAs. However, most prior studies assume vertically propagating shear-wave input, neglecting inclined and azimuthally varying wavefields. This study evaluates the effects of inclination and azimuth in 2D and 3D GRAs at DPDA to assess whether non-vertical wave incidence improves agreement with observed ETFs. Two approaches for modeling inclined waves, the Input Lag Method (ILM) and the Inclined Domain Method (IDM), are compared, with ILM found to be more effective and computationally efficient for large-scale models. A parametric study using ILM shows that inclination angles up to 15{\deg} produce only minor reductions in TTF amplitudes near f0, with limited improvement in ETF agreement. Larger inclination angles reduce amplitudes but introduce systematic shifts in f0 to higher frequencies that are not observed in the ETFs. Azimuthal variation in 3D GRAs has a relatively minor effect, primarily influencing trough amplitudes while leaving f0 and higher-mode peaks largely unchanged.
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Instrumentation and Detectors
Construction and characterisation of the DarkSide-20k veto silicon photo-multiplier tiles
DarkSide-20k collaboration
Silicon photo-multipliers (SiPMs) are state-of-the-art sensors capable of detecting a single photoelectron under cryogenic conditions, with potentially lower radioactivity than widely used photomultiplier tubes. The DarkSide-20k experiment, designed to perform direct dark matter searches using
liquid argon as the target material, employs SiPM technology to detect interactions in the active detector volumes, including the central dual-phase Time Projection Chamber and the Inner and Outer Veto volumes. The vetoes are designed to discriminate against radiogenic
neutron and
cosmic muon backgrounds associated with the dark matter search. This paper describes the completed production and test protocols for the "Veto Tiles" (called vTiles, arrays of 24 SiPMs integrated on a printed
circuit board providing the power distribution and signal amplification); 16 vTiles are grouped into "Veto Photo-Detector Units" to instrument the Inner Veto volume. Each vTile underwent detailed testing at room and cryogenic temperatures, confirming stable operation, high signal-to-noise ratio, and low radioactive contamination, demonstrating the robustness of the proposed design for cryogenic conditions. The final production yield exceeded 87%, surpassing the 80% requirement and corresponding to 1920 Veto Tiles to populate 120 Veto Photo-Detector Units, plus an additional 6% as spares.
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Chemical Physics · Cross-listed from quant-ph
Open-source implementation of the anti-Hermitian contracted Schrödinger equation for electronic ground and excited states
Daniel Gibney, Anthony W Schlimgen and Jan-Niklas Boyn
Efficient simulation of strongly correlated electrons has become a routine tool in molecular electronic structure theory due to recent advances in approximate configuration interaction (CI) techniques. Nonetheless, the quantitative and predictive description of molecular electronic states remains a significant challenge due to the difficulty of computing all-electron correlation beyond CI. Here, we describe a new open-source implementation of the anti-Hermitian contracted Schrödinger equation (ACSE) for use in accurate simulation of all-electron correlation in molecules. In contrast to standard approaches via multireference perturbation theory, the scaling of the ACSE does not depend on the complexity of the strongly correlated reference wavefunction. Furthermore, the ACSE employs the exact electronic
Hamiltonian, rather than an approximate perturbative
Hamiltonian. Our
benchmark results demonstrate good accuracy for main group and transition metal systems, in weakly and strongly correlated regimes, with various basis sets, and for ground and excited states. The results suggest that the ACSE has potential as a scalable and robust technique for simulating all-electron correlation in molecular ground and excited states.
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Instrumentation and Detectors
Owen Lailey, Dusan Sarenac, David G. Cory et al. (+2 more)
Coherent control of
neutrons via Bragg diffraction forms the foundation of perfect
crystal neutron interferometry, facilitating both fundamental tests of
quantum mechanics and applications in
quantum information science. In cavity geometries, perfect
crystals enable
neutron confinement and have been employed in precision measurements of
spin-orbit interactions and for
neutron electric dipole moment (nEDM) searches. However, in these conventional configurations,
neutrons undergo a single pass through the
crystal geometry, placing a physical constraint on both
crystal and in-flight interaction times and measurement sensitivity. In this work, we introduce a
neutron loop cavity that coherently recirculates
neutrons through repeated Bragg reflections between perfect silicon
crystal blades. This structure is predicted to achieve a
neutron survival probability of $\sim64~\%$ for 10,000 Bragg reflections, corresponding to confinement times on the order of seconds. We propose a Schwinger interaction measurement that achieves a $\pi$
spin rotation in 800 Bragg reflections, representing more than a tenfold improvement in sensitivity over recent measurements. Further applications include high-sensitivity nEDM searches targeting the $10^{-27}~$e$\cdot$cm scale, as well as competitive experimental tests of
neutron parity violation, the
neutron lifetime, and the
quantum Zeno effect with
neutrons.
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All authors Owen Lailey, Dusan Sarenac, David G. Cory, Michael G. Huber, Dmitry A. Pushin
Atomic Physics
Angle-resolved photoelectron spectroscopy of the DABCO molecule probed with VUV radiation
Audrey Scognamiglio, Lou Barreau, Constant Schouder et al. (+6 more)
We report a study of the diazabicyclo[2.2.2]octane (DABCO) molecule photoionized using VUV synchrotron radiation in combination with an ion–electron coincidence spectrometer. We determine accurately the adiabatic ionization energy to $7.199\pm0.006$~eV. Two vibrational progressions of DABCO cation ground state are resolved at $847~\text{cm}^{-1}\pm27~\text{cm}^{-1}$ and $1257~\text{cm}^{-1}\pm67~\text{cm}^{-1}$, which we assign to modes of $e'$
symmetry. Analysis of the photoelectron angular distribution shows that the anisotropy parameter depends on the vibrational excitation. This dependence of the $\beta$ parameter with the vibrational excitation is attributed to the scattering of the outgoing wavefunction mediated by high-lying Rydberg states.
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All authors Audrey Scognamiglio, Lou Barreau, Constant Schouder, Denis Cubaynes, Bérenger Gans, Éric Gloaguen, Gustavo A. Garcias, Laurent Nahon, Lionel Poisson
Computational Physics · Cross-listed from math.DS
Hidden Harmonic Structure, Universal Damping, and Stability Bounds in Nonlinear Contact Dynamics
Y. T. Feng
Nonlinear contact dynamics are widely regarded as intrinsically nonlinear systems whose behaviour depends strongly on geometry and impact conditions. Here we show that any one-dimensional conservative contact system satisfying monotone energy-consistent conditions admits two complementary structures: (i) a canonical action-angle representation in physical time, and (ii) an exact harmonic oscillator representation under an energy-based coordinate transformation combined with time reparametrisation. This reveals a hidden linear structure underlying nonlinear contact interactions. Building on this result, we derive a unique universal damping law that preserves linear dissipative dynamics in the transformed harmonic space, and establish a rigorous, closed-form lower bound for the critical timestep in numerical simulations. The framework generalises classical power-law contact models and provides a unified basis for restitution control across arbitrary geometries, recovering known exact solutions as explicit monomial special cases.
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History and Philosophy of Physics · Cross-listed from astro-ph.IM
Speed-Error Cross-Correlation Dating of Ancient Star Catalogues, with Application to the Almagest
Carlos Baiget Orts
We present SESCC (Speed-Error Signals Cross-Correlation), a method for dating ancient
star catalogues from the cross-correlation between
stellar proper-motion speeds and positional residuals. At the true epoch, residuals are independent of proper-motion speed; the epoch estimate is the trial date that minimises this cross-correlation. For ecliptic latitudes, SESCC applies the dot product between speeds and residuals across all catalogue
stars without subset selection or linear modelling. For ecliptic longitudes, SESCC-pairs uses pairwise longitude differences between neighbouring
stars, making the method immune to any global longitude offset by algebraic construction. Validated against Tycho Brahe (1547 CE, true ~1580 CE) and Ulugh Beg (1452 CE, true 1437 CE), and confirmed invariant under offsets of +-6 deg, the method is applied to the Almagest. Both coordinates yield bootstrap distributions with 74% pre-Christian minima, consistent with a Hipparchan origin and inconsistent with a Ptolemaic one. The near-absence of quarter-degree fractions in the Almagest longitudes, explained as the deterministic consequence of Ptolemy's precession correction, provides independent corroboration.
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Data Analysis and Statistics
Neural posterior estimation for scalable and accurate inverse parameter inference in Li-ion batteries
Malik Hassanaly, Corey R. Randall, Peter J. Weddle et al. (+4 more)
Diagnosing the internal state of Li-ion batteries is critical for battery research, operation of real-world systems, and prognostic evaluation of remaining lifetime. By using physics-based models to perform probabilistic parameter estimation via
Bayesian calibration, diagnostics can account for the uncertainty due to model fitness, data noise, and the observability of any given parameter. However,
Bayesian calibration in Li-ion batteries using electrochemical data is computationally intensive even when using a fast surrogate in place of physics-based models, requiring many thousands of model evaluations. A fully amortized alternative is neural posterior estimation (NPE). NPE shifts the computational burden from the parameter estimation step to data generation and model training, reducing the parameter estimation time from minutes to milliseconds, enabling real-time applications. The present work shows that NPE calibrates parameters equally or more accurately than
Bayesian calibration, and we demonstrate that the higher computational costs for data generation are tractable even in high-dimensional cases (ranging from 6 to 27 estimated parameters), but the NPE method can lead to higher voltage prediction errors. The NPE method also offers several interpretability advantages over
Bayesian calibration, such as local parameter sensitivity to specific regions of the voltage curve. The NPE method is demonstrated using an experimental fast charge
dataset, with parameter estimates validated against measurements of loss of lithium inventory and loss of active material. The implementation is made available in a companion repository (https://github.com/NatLabRockies/BatFIT).
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All authors Malik Hassanaly, Corey R. Randall, Peter J. Weddle, Paul J. Gasper, Conlain Kelly, Tanvir R. Tanim, Kandler Smith
Atmospheric and Oceanic Physics
On the White-Noise Limit of the Colored Linear Inverse Model
Cristian Martinez-Villalobos
A recent paper by Lien et al. (2025) introduces the "colored linear inverse model" (colored LIM), in which
stochastic forcing is modeled using Ornstein-Uhlenbeck colored noise rather than idealized white noise. In that work, it is shown that the derivative-based identification formulas used to estimate model parameters do not admit a regular white-noise limit due to the loss of differentiability of the lag-correlation function at zero lag. Here we revisit the white-noise limit from the perspective of the underlying
stochastic differential equations. Treating the colored LIM as an augmented Ornstein-Uhlenbeck system, we show that as the correlation time tau -> 0 the colored-noise-driven system reduces to the classical LIM, and the corresponding stationary covariance satisfies the standard fluctuation-dissipation relation. Re-examining the same linear system used by Lien et al. (2025), we illustrate this convergence numerically. These results highlight a distinction between the singular behavior of derivative-based identification formulas and the regular limiting behavior of the underlying
stochastic model. Taken together with recent results showing convergence of estimated parameters in the white-noise limit, they provide a consistent interpretation in which the colored LIM recovers the classical LIM at the level of
stochastic dynamics even though certain estimation procedures become ill-defined in that limit.
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Applied Physics
Tunable Asymmetric Acoustic Absorption in Ventilated Metasurfaces
Keqiang Lyu, Mohamed Farhat and Ying Wu
Asymmetric sound absorption is essential for advanced acoustic manipulation. However, current frequency modulation and broadbanding highly depend on
geometric reconfiguration, leading to inevitable structural complexity that impedes their practical applications. Here, we propose a tunable, highly efficient, asymmetric ventilated acoustic system comprising two heterogeneous resonators. Specifically, it couples a highly dissipative space-coiling resonator (SCR) as a dark mode for energy consumption, alongside a weakly damped Helmholtz resonator as a bright mode acting as a reflective soft boundary. Theoretical and numerical analyses reveal strong asymmetry within the deep-subwavelength region (with a resonator size of approximately \lambda/9.4), achieving 99% absorption for left-incident waves and 98% reflection for right-incident ones. Furthermore, the SCR introduces an interesting degree of freedom for acoustic tuning. Simply rotating the resonator induces a 92% absorption drop (~11 dB attenuation), functioning as an "Acoustic Switch". Moreover, this rotation significantly shifts the operating band. By parallel-coupling multi-angle isomorphic resonators, we achieve efficient broadband absorption (>0.8) from 325 to 375 Hz, offering an attractive paradigm for tunable acoustic metasurfaces and ventilated absorbers.
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Optics
Simultaneous plane illumination and detection in confocal microscopy using a mode-selective photonic lantern
Rodrigo Itzamná Becerra-Deana, Simon Desrochers, Raphaël Maltais-Tariant et al. (+5 more)
Confocal microscopy is the cornerstone of cellular biology and biomedical research due to its non-destructive imaging, compatibility with live
cells, sensitivity, optical sectioning, and subcellular resolution. To meet the demand for rapid three-dimensional imaging, we propose a novel approach using a mode-selective photonic lantern (MSPL). This fiber-based device transforms single-mode light into multiple linearly polarized modes, allowing simultaneous detection of multiple planes. Using a four-port MSPL to manipulate three group modes (LP$_{01}$, LP$_{11}$, and LP$_{21}$), we demonstrate high-throughput imaging simultaneously with multiple planes. This technique exploits differences in focus sections across modes, enabling individual multi-plane detection via a spatial division multiplexer, with some trade-off in resolution and field of view.
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All authors Rodrigo Itzamná Becerra-Deana, Simon Desrochers, Raphaël Maltais-Tariant, Simon Brais-Brunet, Guillaume Ramadier, Stéphane Virally, Lucien E. Weiss, Caroline Boudoux
Fluid Dynamics
A Multimodal Vision Transformer-based Modeling Framework for Prediction of Fluid Flows in Energy Systems
Kiran Yalamanchi, Shivam Barwey, Ibrahim Jarrah et al. (+1 more)
Computational fluid dynamics (CFD) simulations of complex fluid flows in energy systems are prohibitively expensive due to strong nonlinearities and multiscale-multiphysics interactions. In this work, we present a
transformer-based modeling framework for prediction of fluid flows, and demonstrate it for high-pressure gas injection phenomena relevant to reciprocating engines. The approach employs a hierarchical
Vision Transformer (SwinV2-UNet) architecture that processes
multimodal flow
datasets from multi-fidelity simulations. The model architecture is conditioned on auxiliary
tokens explicitly encoding the data modality and time increment. Model performance is assessed on two different tasks: (1) spatiotemporal rollouts, where the model autoregressively predicts the flow state at future times; and (2) feature transformation, where the model infers unobserved fields/views from observed fields/views. We train separate models on
multimodal datasets generated from in-house CFD simulations of argon jet injection into a nitrogen environment, encompassing multiple grid resolutions,
turbulence models, and equations of state. The resulting data-driven models learn to generalize across resolutions and modalities, accurately
forecasting the flow
evolution and reconstructing missing flow-field information from limited views. This work demonstrates how large
vision transformer-based models can be adapted to advance predictive modeling of complex fluid flow systems.
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All authors Kiran Yalamanchi, Shivam Barwey, Ibrahim Jarrah, Pinaki Pal
Physics Education
What does it mean to think like a physicist? Insights from physics graduate students
Apekshya Ghimire and Chandralekha Singh
Learning to think like a physicist (LTP) is often cited as a central goal of graduate physics education, yet what this means in practice and the extent to which physics graduate education prepares students to develop LTP and view LTP as valuable to their research and teaching remain unclear. This interview-based study, conducted with seven physics graduate students at one US public research university, explores how students define thinking like a physicist and how their coursework and research experiences correlate with this development. Students emphasized that physics uniquely requires integrating physical and mathematical concepts in ways that go beyond other science disciplines. Our findings show that physics core courses, particularly electricity and magnetism, frequently emphasize mathematical techniques and content coverage at a rapid pace at the expense of deeper conceptual engagement and development of LTP. In contrast, physics elective courses and research experiences were more synergistic with and effective in fostering conceptual understanding, problem-solving skills, and identity development as physicists. Because graduate students simultaneously take core courses, conduct research and teach introductory physics, their perspectives on LTP are particularly valuable in how physics departments may consider transforming their preparation. Their voices highlight how this transformative stage of training can either support or hinder the development of physicist thinking.
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Space Physics
Proton Temperature Anisotropy Across Interplanetary Shocks: A Statistical Analysis with WIND observations
Zeping Jin, Lingling Zhao, Xingyu Zhu et al. (+6 more)
Interplanetary (IP) shocks efficiently modify the
proton temperature anisotropy of the
solar wind. Analyzing ~800 IP shocks observed by the Wind spacecraft from 1997-2024, we present a statistical study of upstream and downstream
proton temperature anisotropy and its dependence on shock geometry, compression, and distance from the shock. We find that (1) quasi-perpendicular shocks produce a pronounced enhancement of perpendicular temperature downstream (Tperp > Tpara), whereas parallel shocks remain near isotropic downstream due to typically stronger upstream Tpara; (2) comparisons with the Chew-Goldberger-Low (CGL) double-adiabatic model reveal geometry-dependent deviations. CGL overestimates downstream perpendicular heating and underestimates parallel heating at quasi-perpendicular shocks, with the opposite trend at quasi-parallel shocks, highlighting the importance of non-adiabatic processes beyond simple compression; (3) Shock-driven anisotropy is strongly localized near the shock and gradually relaxes toward typical
solar wind conditions farther downstream as the shock's influence diminishes; and (4) downstream anisotropy is regulated by kinetic instabilities, with quasi-perpendicular shocks constrained by
proton cyclotron and mirror instabilities and quasi-parallel shocks limited by the parallel firehose instability. Together, these results show that the
evolution of temperature anisotropy at interplanetary shocks is controlled by shock geometry, localized processes, and instability driven regulation.
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All authors Zeping Jin, Lingling Zhao, Xingyu Zhu, Vladimir Flosinski, Gary P. Zank, Jakobus Le Roux, Yiming Jiao, Ashok Silwal, Nibuna S. M. Subashchandar
Instrumentation and Detectors
ITACA revisited: Ion Tracking Apparatus with CMOS ASICs
J.J Gómez-Cadenas, L. Arazi, G. Martínez-Lema et al. (+3 more)
High-pressure xenon gas TPCs with electroluminescent amplification (HPXeEL) provide detailed topological reconstruction of charged-particle trajectories, offering a distinctive two-electron signature for neutrinoless double beta decay ($0\beta\beta\nu$) searches. We have recently proposed ITACA, a detector concept that images both the electron track and the corresponding ion track, carried by the positive ions drifting in the opposite direction. While electrons drift rapidly to the anode for standard EL imaging, the positive ions drift slowly to the cathode with millimetre-scale
diffusion, allowing time to determine the event energy and barycenter and to position a movable ion detector at the projected arrival point of the ion cloud. We present a conceptual design of the ITACA detector, addressing key feasibility questions. First, we define the detector geometry and operating parameters for a 1-tonne-scale instrument at 15 bar, including a modular tiled electroluminescent structure. Second, we present the conceptual design of the Magnetically Actuated Rotor System (MARS), the mechanism that positions the ion sensor at any $(r, \theta)$ coordinate below the cathode, and show that the expected movement time is fast enough to retain $\sim95\%$ of the drift volume for ion detection, while not significantly perturbing the gas on the scales of the ion drift. Third, we propose using a Topmetal CMOS ASIC-based ion detector as an alternative to the molecular sensor approach described in our original work, enabling real-time, 3D imaging of the ion track without the need for offline
laser scanning. Finally, we estimate the sensitivity of the proposed apparatus, showing that enhanced topological discrimination from the ion track, combined with an ultra-low background design, allows exploration of $0\beta\beta\nu$ half-lives in excess of $10^{28}$ yr.
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All authors J.J Gómez-Cadenas, L. Arazi, G. Martínez-Lema, J. Renner, S.R. Soleti, S. Torelli
Fluid Dynamics
Parametric Reduced-Order modeling and Closed-Loop Control of Tandem-Cylinder Wakes
Tea Vojkovic, Dimitris Boskos and Abel-John Buchner
The flow around two circular cylinders arranged in a tandem exhibits complex wake interactions that lead to amplified unsteady loads, particularly in the co-shedding regime where a fully developed wake forms in the gap between the cylinders. Although various control strategies have been proposed to mitigate these effects, most prior studies have focused primarily on load alleviation. Complete suppression of
vortex shedding, both in the gap region and in the wake of the second cylinder, has so far only been achieved using open-loop approaches. In this work, we propose a closed-loop control framework for suppressing
vortex shedding in tandem cylinder flows in the co-shedding regime. Focusing on low Reynolds numbers and sufficiently large spacings, we derive a parametric reduced-order model using a global weakly nonlinear analysis of the incompressible Navier-Stokes equations. The model is generalized to account for time dependent forcing and facilitates the real time prediction of the flow
evolution. Using this model, we design a model predictive controller and apply it to the full-order system via velocity measurements and volumetric forcing. The approach is demonstrated for a cylinder spacing of eight diameters.
Vortex shedding is fully suppressed in both the gap region and the downstream wake for Reynolds numbers $Re=50$, $60$, and $70$, while a significant reduction in flow unsteadiness is achieved at $Re=80$. We further show that effective control is possible with limited sensing: suppression is achieved using a single measurement point for $Re=50$ and two-point measurements for $Re=60$ and $70$.
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Chemical Physics
The correlation discrete variable representation revisited
Uwe Manthe
The correlation discrete variable representation (CDVR) enables efficient
quantum dynamics calculation with the multi-layer multi-configurational time-dependent Hartree (MCTDH) approach on general potential energy surfaces. It employs a time-dependent quadrature to compute potential energy
matrix elements, thereby eliminating the need to refit the potential to a sum of products form. The non-hierarchical CDVR conserves the inherent
symmetry properties of tree-shaped wavefunction representations and drastically reduces the number of grid points compared to the original hierarchical CDVR. However, it requires projection on the space spanned by the single-hole functions (SHFs) at each node of the tree, which can introduce unphysical couplings for unconverged basis sets. In this work, the non-hierarchical CDVR is revisited and a revised approach that avoids explicit projection on the single-hole space is introduced. The computational costs of the revised approach scale favorably with the number of single-particle functions (SPFs): for a tree with three edges at each node and $n$ SPFs at each edge, a n^4 scaling is achieved. Furthermore, a revised scheme that uses artificial SPFs to systematically increase the accuracy of the CDVR quadrature is presented. Computations studying the photodissociation of NOCl, the vibrational states of methyl, and the non-adiabatic
quantum dynamics of photoexcited pyrazine demonstrate the accuracy and efficiency of the revised non-hierarchical CDVR. Notably, for the 24-dimensional pyrazine system the use of the CDVR does not increase the required CPU time compared to calculations utilizing the sum of products form of the vibronic coupling model.
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Optics · Cross-listed from cs.ET
Photonic convolutional neural network with pre-trained in situ training
Saurabh Ranjan, Sonika Thakral and Amit Sehgal
Convolutional neural networks (CNNs) have transformed image processing, but the energy consumption and inference latency of electronic based implementations remain fundamental bottlenecks. These limitations have motivated the search for alternative hardware architectures beyond Complementary metal-
oxide-
semiconductor (CMOS) chips. Optical systems can perform linear
matrix operations at the speed of light with extremely low energy dissipation, making them attractive for CNN acceleration. However, building a fully coherent photonic CNN that performs both linear and nonlinear operations and training it efficiently remains an open challenge. Here we present a fully photonic convolutional neural network (PCNN) that executes image classification in the optical domain, including convolution, max-pooling, nonlinear activation, and fully connected layers. The network achieves 94.49 percent accuracy on the MNIST
dataset distributed across Mach Zehnder Interferometer (MZI) meshes, weighted Multimode Interferometer (MMI) trees, and a microring resonator based nonlinearity. A mathematically exact differentiable digital twin, enables backpropagation for ex situ pre training, reaches 97.45 percent digital accuracy. Trained phases are transferred one-to-one to the photonic hardware and refined via a gradient free
algorithm that estimates the full gradient with only two forward passes. The architecture exhibits inherent robustness to non idealities, under the compound effect of propagation loss, MZI insertion loss, fabrication disorder, and thermal crosstalk. A bottom-up power analysis yields 10.83 W static chip consumption and 843 ns inference latency, translating to 220 to 330 times greater energy efficiency than state of the art electronic GPUs for single-image inference.
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Physics and Society
The Retraction Epidemic in Science Across Publishers, Fields, and Countries
Sara Venturini, Alessandra Urbinati, Paola Gallo et al. (+2 more)
Retractions serve as an indicator of failures in research integrity, yet most analyses focus on absolute counts rather than risk per paper. We use one of the largest open bibliographic databases to develop incidence metrics normalized by population: retractions per publication and per active author annually. Applying an epidemiological framework that models counts with exposure, we find evidence of exponential growth in retraction incidence, with approximately a 5-year doubling time at both the paper and author levels. These patterns vary significantly across fields, publishers, and countries. While scientific output is becoming more democratized globally, retractions are concentrated in fewer countries, creating a "concentration" paradox that calls for targeted monitoring. Despite exponential growth, the absolute incidence remains low (0.12% in 2021), allowing for corrective intervention. Incidence-based monitoring provides a framework for evaluating policies that safeguard research integrity at scale.
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All authors Sara Venturini, Alessandra Urbinati, Paola Gallo, Jessica T. Davis, Alessandro Vespignani
Atmospheric and Oceanic Physics
A proposal for the safety and controllability requirements that SRM systems should meet
E. Waxman, A. Spector, Y. Lederer et al. (+5 more)
Solar Radiation Modification (SRM) may be the only way to limit global warming in the coming decades, leading to increased interest in the subject and to the expansion of related research & development (R&D) activity. Defining the safety and controllability requirements that any SRM system should meet is crucial for directing R&D activities and enabling governments to make informed decisions on the development and possible implementation of such systems. We present an initial proposal for this set of requirements, which also guides Stardust's R&D, as a basis for further discussion and consideration. While we focus on SRM systems based on Stratospheric Aerosol Injection (SAI), the proposed principles may be applicable more broadly.
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All authors E. Waxman, A. Spector, Y. Lederer, Y. Segev, T. Kislev, Y. Yedvab, D. Kushnir, R. Yahav
Computational Physics
Magboltz-GUI: a Python-based graphical user interface for Magboltz
Michele Renda. Dan Andrei Ciubotaru and Călin Alexa
Magboltz is widely used to compute electron transport properties in gas mixtures for detector applications. Its text-based workflow, however, can be a barrier for routine use, especially for users who are not already familiar with the program. We present Magboltz-GUI, a Python-based graphical user interface for defining gas mixtures, configuring simulation parameters, running Magboltz, and visualizing or exporting the resulting. The tool is designed as a lightweight frontend for common tasks in research and teaching environments involving gaseous detectors, including micropattern technologies such as Micromegas. This paper describes the software implementation, main interface components, and its availability as an open-source distributed package via Python tools.
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Optics
Temporal soliton generation in an ultra-high-effective-Q Kerr resonator enabled by Raman gain
Georges Semaan, Yifan Sun, Nicolas Englebert et al. (+2 more)
We demonstrate temporal pattern formation in a coherently driven fiber ring cavity whose effective finesse is continuously reconfigured using distributed Raman amplification. We achieve an effective finesse of up to $\mathcal{F}_{\mathrm{eff}}\approx800$, corresponding to a linewidth of approximately 725 Hz ($Q\approx2.7\times10^{11}$) at 1555 nm. By exploiting the resulting increase in effective
photon lifetime, we excite stable temporal cavity
solitons and generate a low-repetition-rate frequency comb with a spacing of 580~kHz. Finally, we analyze the impact of the Raman loss-compensation mechanism, particularly its associated noise and show that a trade-off exists between
soliton excitation threshold and stability.
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All authors Georges Semaan, Yifan Sun, Nicolas Englebert, Simon-Pierre Gorza, François Leo
Instrumentation and Detectors
X-ray Response of the Fully-Depleted, p-Channel SiSeRO-CCD
Julian Cuevas-Zepeda, Joseph Noonan, Claudio Chavez et al. (+6 more)
We present an X-ray characterization of a fully depleted, 725 $\mu$m thick p-channel SiSeRO-CCD. Measurements with a $^{55}$Fe source yield an energy resolution of $54 \pm 0.9$ eV ($14.6 \pm 0.25 e^{-}$) at 5.9 keV for single-pixel events, indicating that the SiSeRO amplifier preserves the intrinsic charge resolution of the CCD under multi-sample non-destructive readout. Characterization with a $^{241}$Am source extends the response to higher-energy
photons, with reconstructed spectral features observed between 9-26 keV and the 59.5 keV $\gamma$ emission. These measurements, together with a
muon-derived
diffusion calibration, show that charge transport and
diffusion are consistent with interactions spanning the full sensor depth. These results demonstrate that the SiSeRO-CCD simultaneously achieves sub-electron noise performance and efficient charge collection in a thick, fully depleted silicon detector. This combination enables X-ray spectroscopy across a broad energy range while maintaining sensitivity to faint signals.
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All authors Julian Cuevas-Zepeda, Joseph Noonan, Claudio Chavez, Miguel Sofo-Haro, Nathan Saffold, Juan Estrada, Kevan Donlon, Chris Leitz, Steve Holland
Optics · Cross-listed from cond-mat.dis-nn
Crossovers from nonlinear wave-packet acceleration to wave-mixing and self-trapping in the Hatano-Nelson model
Bertin Many Manda and Vassos Achilleos
We demonstrate that wave amplification enables even weak nonlinearities to reshape linear wave-packet transport in nonreciprocal systems. We study the dynamics of bulk Gaussian wave-packets in the Hatano–Nelson model with on-site cubic nonlinearity. We show that the interplay between nonlinearity and amplification generates growing frequency shifts that drive the wave-packet through three successive dynamical regimes: an early nonlinear-skin regime with coherent propagation, an intermediate wave-mixing regime driven by eigenmode resonances, and a self-trapping regime in which part of the packet localizes while the remainder ballistically spreads along the system favored direction. The crossover time scales are set by the width and averaged spacing of the eigenfrequency spectrum. Crucially, within the nonlinear-skin regime, we derive analytical predictions for the wave-packet dynamics and show that nonlinearity couples amplification, dispersion, and nonreciprocity, thereby modifying the magnitude of the wave-packet acceleration and introducing an explicit time dependence into its
evolution. Focusing nonlinearities suppress the acceleration and cause it to decrease in time, whereas defocusing nonlinearities enhance it and cause it to increase. We further show that nonlinear interactions typically break down the wave-packet before the non-Hermitian jump can occur. Our results provide a route toward accurate control of waves in nonreciprocal metamaterials.
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Optics
Theory of Lineshapes in Optical-Optical Double Resonance Spectroscopy
Kevin K. Lehmann
This paper presents lineshapes for molecular Optical-Optical Double Resonance (DR) Spectroscopy with arbitrary strength for both pump and probe field using the steady-state solutions for the 3-level density
matrix. When the Doppler broadening can be neglected, the results are analytical, and the probe spectrum is a pair of Lorentzian lines that display Autler-Townes splitting, and each has an angular frequency half-width half maximum equal to the relaxation rates, which are all assumed equal. When Doppler broadening is introduced, one must resort to numerical integration except for the limit of weak pump and probe fields. When the Doppler width is assumed much larger than the pump and probe Rabi Frequencies, the calculated DR lineshapes are found to be Lorentzian with a strong pump field limit that is proportional to the pump Rabi frequency, what is commonly known as power broadening. However, the width does not equal the Rabi frequency and is different for co- and counter-propagating pump and probe fields. Furthermore, that broadening is largely inhomogeneous, despite the Lorentzian shape. The saturation power is found to be about 4 times higher than for the bare probe transition with the same relaxation rate, dramatically lower than that expected if the width is interpreted as homogeneous.
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Instrumentation and Detectors · Cross-listed from hep-ex
Retrieval-Augmented Question Answering over Scientific Literature for the Electron-Ion Collider
Tina. J. Jat, T. Ghosh and Karthik Suresh
To harness the power of
Language Models in answering domain specific specialized technical questions,
Retrieval Augmented Generation (RAG) is been used widely. In this work, we have developed a Q&A application inspired by the
Retrieval Augmented Generation (RAG), which is comprised of an in-house database indexed on the arXiv articles related to the Electron-Ion
Collider (EIC) experiment - one of the largest international scientific collaboration and incorporated an open-source LLaMA model for answer generation. This is an extension to it's proceeding application built on proprietary model and Cloud-hosted external knowledge-base for the EIC experiment. This locally-deployed RAG-system offers a cost-effective, resource-constraint alternative solution to build a RAG-assisted Q&A application on answering domain-specific queries in the field of experimental
nuclear physics. This set-up facilitates data-
privacy, avoids sending any pre-publication scientific data and information to public domain. Future improvement will expand the knowledge base to encompass heterogeneous EIC-related publications and reports and upgrade the application pipeline orchestration to the LangGraph framework.
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Geophysics · Cross-listed from astro-ph.IM
A research roadmap for assessing the feasibility of warming Mars
E. S. Kite, A. Essunfeld, M. H. Hecht et al. (+22 more)
This roadmap outlines research pathways to determine whether Mars could be warmed with non-biological methods. It does not presuppose that warming Mars is desirable; its purpose is to identify what would need to be true for Mars to be warmed, what it would cost, and what could go wrong. Three complementary research tracks appear promising. Solid-state greenhouse membranes offer local warming, aiding water harvesting, food production, and oxygen supply near human bases. Orbiting reflectors can warm key sites such as bases and CO$_2$-ice reservoirs, although a large combined area would be required. Strengthening Mars' natural greenhouse effect might warm large regions or the globe, although many aspects remain to be worked out. Each approach carries scientific and technical risks that research must address. Near-term priorities are on-Earth testing of key parameters that will determine whether engineered aerosol warming is realistically possible, assessing whether exponential production of bioplastic habitats is possible, and designing at-Mars process experiments. In the near term, the research proposed here is closely aligned with and supports research needed to understand Mars' atmosphere and volatile
evolution and hazards to human explorers. The main external uncertainty is whether or not launch costs continue to fall. This is early-stage research, and we discuss key near-term decision points, alternative pathways, and payoffs if research outcomes are negative. We also outline build-out pathways if research succeeds and demand exists. Relatively modest research investments would keep open the option of extending life beyond Earth as Mars' scientific exploration continues.
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All authors E. S. Kite, A. Essunfeld, M. H. Hecht, M. A. Mischna, R. Wordsworth, H. Mohseni, A. Boies, N. Averesch, S. Ansari, M. I. Richardson, E. A. DeBenedictis, D. Stork, A. L. Bamba, C. J. Handmer, C. Jourdain, R. Ramirez, C. E. Mason, A. Kling, A. S. Braude, A. Dumitrescu, S. P. Worden, J. Cumbers, N. Lanza, R. Quayum, C. S. Cockell
Data Analysis and Statistics · Cross-listed from hep-ph
Many Wrongs Make a Right: Leveraging Biased Simulations Towards Unbiased Parameter Inference
Ezequiel Alvarez, Sean Benevedes, Manuel Szewc et al. (+1 more)
In particle physics, as in many areas of science, parameter inference relies on simulations to bridge the gap between theory and experiment. Recent developments in simulation-based inference have boosted the sensitivity of analyses; however, biases induced by simulation-data mismodeling can be difficult to control within standard inference pipelines. In this work, we propose a Template-Adapted Mixture Model to confront this problem in the context of signal fraction estimation: inferring the population proportion of signal in a mixed sample of signal and background, both of which follow arbitrarily complex distributions. We harness many biased simulations to perform data-driven estimates of each process distribution in the signal region, substantially reducing the bias on the signal fraction due to the domain shift between simulation and reality. We explore different methodological choices, including model selection, feature representation, and statistical method, and apply them to a Gaussian toy example and to a semi-realistic di-
Higgs measurement. We find that the presented methods successfully leverage the biased simulations to provide estimates with well-calibrated uncertainties.
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All authors Ezequiel Alvarez, Sean Benevedes, Manuel Szewc, Jesse Thaler
Optics · Cross-listed from quant-ph
High-bandwidth Coherence Cloning using Optical-Phase-Locking Feedforward
Chen Jia, Zhen-Xing Hua, Yu-Xin Chao et al. (+1 more)
Ultra-narrow-linewidth
lasers with suppressed high-frequency phase noise are critical for
quantum control and precision metrology. While optical phase locking (OPL) is the standard technique for cloning the coherence of such sources, its effectiveness is often limited at high frequencies by feedback latency. We present a robust feedforward architecture that overcomes this limitation by recycling and demodulating the existing master-slave beat signal to drive a single electro-optic modulator for near-instantaneous noise cancellation. This approach eliminates the extraneous sidebands and transmission losses typical of more complex modulators. Through active stabilization of the beat amplitude and demodulation phase, we demonstrate robust suppression exceeding 30 dB from 10 kHz to 10 MHz. This hardware-efficient framework is readily compatible with standard OPL setups, offering a scalable solution for high-fidelity coherent control.
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All authors Chen Jia, Zhen-Xing Hua, Yu-Xin Chao, Meng Khoon Tey
Biological Physics · Cross-listed from cs.ET
QuantumXCT: Learning Interaction-Induced State Transformation in Cell-Cell Communication via Quantum Entanglement and Generative Modeling
Selim Romero, Shreyan Gupta, Robert S. Chapkin et al. (+1 more)
Inferring
cell-
cell communication (CCC) from single-
cell transcriptomics remains fundamentally limited by reliance on curated ligand-receptor databases, which primarily capture co-expression rather than the system-level effects of signaling on cellular states. Here, we introduce QuantumXCT, a hybrid
quantum-classical generative framework that reframes CCC as a problem of learning interaction-induced state transformations between cellular state distributions. By encoding transcriptomic profiles into a high-dimensional
Hilbert space, QuantumXCT trains parameterized
quantum circuits to learn a
unitary transformation that maps a baseline non-interacting cellular state to an interacting state. This approach enables the discovery of communication-driven changes in cellular state distributions without requiring prior biological assumptions. We validate QuantumXCT using both synthetic data with known ground-truth interactions and single-
cell RNA-seq data from ovarian cancer-fibroblast co-culture model. The QuantumXCT model accurately recovered complex regulatory dependencies, including feedback structures, and identified dominant communication hubs such as the PDGFB-PDGFRB-STAT3 axis. Importantly, the learned
quantum circuit is interpretable: its entangling
topology was translated into biologically meaningful interaction networks, while post hoc contribution analysis quantified the relative influence of individual interactions on the observed state transitions. Notably, by shifting CCC inference from static interaction lookup to learning data-driven state transformations, QuantumXCT provides a generative framework for modeling intercellular communication. This work establishes a new paradigm for de novo discovery of communication programs in complex biological systems and highlights the potential of
quantum machine learning in the context of single-
cell biology.
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All authors Selim Romero, Shreyan Gupta, Robert S. Chapkin, James J. Cai