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Saturday 12 September

Medical Physics

Fail-closed conformal multiresolution error control for conservative three-dimensional dose remapping in synthetic phantoms

Yuntao Wang

Conservative dose remapping can be formulated by transporting mass and deposited energy across nonmatching grids, but fixed sampling uses the same number of points per active source cell regardless of case difficulty. We developed conformal multiresolution error control (CoMERC), a fail-closed multilevel quasi-Monte Carlo (QMC) controller for reference-relative target-cell allocation error in a fixed piecewise-constant source model with known deformation. Two randomized nested replicates were evaluated at a probe level of 4 and candidate levels of 8 and 16. Four endpoints were controlled jointly: reference-mass-weighted global, high-gradient, and density-gradient-threshold root-mean-square error, plus eligible-cell maximum absolute error. A split-conformal multiplier was calibrated from 240 synthetic cases, frozen, and evaluated on 400 independent cases from the same generator and 120 cases from a prespecified shifted generator. In the primary set, joint coverage was 394/400 (98.50%; one-sided 95% lower limit, 97.06%), 388/400 cases (97.00%; lower limit, 95.18%) received an output, and 0/388 released outputs exceeded any tolerance (one-sided 95% upper limit, 0.769%). Final actions were level 8 for 190 cases, level 16 for 198, and ABSTAIN for 12. The mean of the case-normalized, policy-implied production-sample ratios was 0.5844, with each case normalized to always running both randomized replicates through level 16; the prespecified 95th-percentile bootstrap upper limit was 0.6194. All seven primary gates passed. In the shifted-generator set, 113/120 cases were released and one released output exceeded a tolerance. CoMERC provided marginal finite-sample error control and lower modeled production-sample work in the locked synthetic population, but not patient-level, registration-level, conditional-on-release, or clinical safety validation.
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Materials Science

Physics-aware global Rietveld refinement for high-energy X-ray diffraction microscopy with application to reconstructing intragranular orientation and strain fields

Carter K. Cocke, Eitan Camacho, Sara F. Gorske et al. (+2 more)

High-energy X-ray diffraction microscopy (HEDM) has emerged as a critical technique for studying the microstructure and, increasingly, strain fields in solids. However, current algorithmic or experimental methods to obtain intragranular fields are time-intensive, provide limited spatial resolution, or yield stress and strain fields that do not satisfy the universal laws of deformation (compatibility and equilibrium). In the context of standard HEDM, a novel physics-aware approach is presented in which the physics of deformation is included in the forward diffraction simulation to ensure that the reconstructed fields are physically meaningful. The entire simulated and experimental diffractograms are compared with a differentiable optimal transport–type objective, and a Rietveld refinement is carried out globally on the internal fields and grain topology using gradient-based optimization. The method is developed, verified with synthetic data, and demonstrated experimentally using near-field HEDM data from aluminum oxynitride (a brittle ceramic), with a reference implementation released as PARA-X. The reconstructions show remarkable improvement over existing methods (improved completeness and loss), and the high-fidelity, high-resolution recovery paves the way for using HEDM to study fine-scale deformation mechanics over large polycrystalline volumes.
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All authors Carter K. Cocke, Eitan Camacho, Sara F. Gorske, Katherine T. Faber, Kaushik Bhattacharya

Chaotic Dynamics

First-order integrability-breaking phase transitions in dynamical systems

Anne Ketri P. da Fonseca, Marcelo de Almeida Presotto, Diego F. M. Oliveira et al. (+1 more)

We investigate a discontinuous route from integrability to chaos using a confined stochastic random walk and a deterministic stadium-like billiard. In both systems, the stationary diffusive observable exhibits a finite jump at the transition: it vanishes at the unperturbed limit but approaches a finite, geometry-controlled value for arbitrarily small nonzero perturbations, providing the characteristic order-parameter signature of a first-order transition. Despite this discontinuity, the relaxation timescale diverges as the transition is approached, revealing critical slowing down. Both models exhibit normal diffusion with $\beta=1/2$, a perturbation-independent stationary state with $\alpha=0$, and a crossover iteration scaling as $n_x\propto\lambda^{-2}$, yielding $z=-2$, where $\lambda$ denotes the corresponding perturbation parameter. The common exponent set $(\alpha,\beta,z)=(0,1/2,-2)$ originates from the same coarse-grained mechanism: normal diffusion within a finite accessible domain with a diffusion coefficient that vanishes quadratically at the transition. The agreement between stochastic transport and deterministic chaotic scattering provides strong evidence for a common class of discontinuous dynamical transitions and extends the statistical-mechanics description of phase transitions to integrability-breaking dynamics.
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All authors Anne Ketri P. da Fonseca, Marcelo de Almeida Presotto, Diego F. M. Oliveira, Edson D. Leonel

Chaotic Dynamics

First-Order Transition to Chaos with Critical Slowing Down

Anne Ketri P. da Fonseca, Marcelo de Almeida Presotto, Diego F. M. Oliveira et al. (+1 more)

Can the transition from integrability to chaos be discontinuous? We show that it can, and that the resulting first-order dynamical transition coexists with critical slowing down. Using an analytically tractable confined random walk and a deterministic stadium-like billiard, we find a finite jump of the stationary diffusive observable at the transition while the relaxation time diverges. Both systems display normal diffusion and the same exponent set $(\alpha,\beta,z)=(0,1/2,-2)$. We trace this agreement to a common coarse-grained mechanism: diffusion in a finite accessible domain with a diffusion coefficient that vanishes quadratically with the perturbation. The results identify a discontinuous route from integrability to chaos and provide evidence for a broader universality class of first-order dynamical transitions.
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All authors Anne Ketri P. da Fonseca, Marcelo de Almeida Presotto, Diego F. M. Oliveira, Edson D. Leonel

Friday 11 September

Instrumentation and Detectors

The Skin Detector System of the LZ Dark Matter Experiment

D.S. Akerib, A.K. Al Musalhi, F. Alder et al. (+209 more)

This paper presents the design, calibration, and performance of the Skin Detector component of the LUX-ZEPLIN (LZ) dark matter experiment. The Skin Detector consists of approximately 2 tonnes of liquid xenon instrumented with 131 photomultiplier tubes, surrounding the central time-projection chamber and functions as an active veto system for background rejection. Energy calibration with monoenergetic gamma sources established a position-dependent energy scale and determined prompt and delayed veto thresholds. Radon decays in the Skin can be identified with less than 15~mm spatial resolution, revealing stable convective flow patterns with measured velocities ranging from 2-4 mm/s that persisted throughout extended data-taking periods. The achieved Skin veto threshold meets or exceeds the design goal of 100~keV throughout the Skin volume. The prompt veto efficiency for gamma rays emitted following electron capture in $^{127}$Xe is found to be ($88 \pm 2$)%, consistent with the simulated value of ($90.4 \pm 0.6$)%. M-shell EC decays are used to validate the LZ detector sensitivity for low-mass dark matter during the first science run.
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All authors D.S. Akerib, A.K. Al Musalhi, F. Alder, B.J. Almquist, C.S. Amarasinghe, A. Ames, T.J. Anderson, N. Angelides, H.M. Araújo, J.E. Armstrong, M. Arthurs, A. Baker, S. Balashov, J. Bang, J.W. Bargemann, E.E. Barillier, K. Beattie, A. Beauchene, A. Bhatti, T.P. Biesiadzinski, H.J. Birch, E. Bishop, G.M. Blockinger, C.A.J. Brew, P. Brás, S. Burdin, M.C. Carmona-Benitez, M. Carter, A. Chawla, Y.T. Chin, S. Contreras, M.V. Converse, R. Coronel, A. Cottle, G. Cox, D. Curran, C.E. Dahl, I. Darlington, S. Dave, A. David, J. Delgaudio, S. Dey, L. de Viveiros, L. Di Felice, C. Ding, J.E.Y. Dobson, E. Druszkiewicz, S. Dubey, C.L. Dunbar, S.R. Eriksen, N.M. Fearon, N. Fieldhouse, S. Fiorucci, H. Flaecher, E.D. Fraser, T.M.A. Fruth, P.W. Gaemers, R.J. Gaitskell, A. Geffre, J. Genovesi, C. Ghag, J. Ghamsari, A. Ghosh, S. Ghosh, R. Gibbons, S. Gokhale, J. Green, M.G.D. van der Grinten, J.J. Haiston, C.R. Hall, T. Hall, R.N. Hampp, S.J. Haselschwardt, M.A. Hernandez, S.A. Hertel, G.J. Homenides, M. Horn, D.Q. Huang, D. Hunt, E. Jacquet, R. James, K. Jenkins, A.C. Kaboth, A.C. Kamaha, M.K. Kannichankandy, D. Khaitan, A. Khazov, J. Kim, Y.D. Kim, D. Kodroff, E.V. Korolkova, H. Kraus, S. Kravitz, L. Kreczko, V.A. Kudryavtsev, T.A. Kumar, C. Lawes, E.B. Leon, D.S. Leonard, K.T. Lesko, C. Levy, Z. Li, J. Lin, A. Lindote, W.H. Lippincott, J. Long, M.I. Lopes, W. Lorenzon, C. Lu, S. Luitz, V. Mahajan, P.A. Majewski, A. Manalaysay, R.L. Mannino, R.J. Matheson, C. Maupin, M.E. McCarthy, D.N. McKinsey, J. McLaughlin, J.B. McLaughlin, R. McMonigle, B. Mitra, E. Mizrachi, M.E. Monzani, K. Morå, E. Morrison, B.J. Mount, M. Murdy, A.St.J. Murphy, H.N. Nelson, F. Neves, A. Nguyen, C.L. O'Brien, F.H. O'Shea, I. Olcina, K.C. Oliver-Mallory, J. Orpwood, K.Y. Oyulmaz, K.J. Palladino, N.J. Pannifer, S.J. Patton, B. Penning, G. Pereira, E. Perry, T. Pershing, A. Piepke, S.S. Poudel, Y. Qie, J. Reichenbacher, G.R.C. Rischbieter, E. Ritchey, H.S. Riyat, R. Rosero, N.J. Rowe, T. Rushton, D. Rynders, S. Saltão, D. Santone, A.B.M.R. Sazzad, R.W. Schnee, G. Sehr, B. Shafer, S. Shaw, W. Sherman, K. Shi, T. Shutt, C. Silva, G. Sinev, J. Siniscalco, A.M. Slivar, A.M. Softley-Brown, R. Smith, V.N. Solovov, P. Sorensen, J. Soria, T.J. Sumner, A. Swain, M. Szydagis, D.R. Tiedt, D.R. Tovey, J. Tranter, M. Trask, K. Trengove, M. Tripathi, A. Usón, A.C. Vaitkus, O. Valentino, V. Velan, A. Wang, J.J. Wang, Y. Wang, L. Weeldreyer, T.J. Whitis, K. Wild, M. Williams, J. Winnicki, L. Wolf, F.L.H. Wolfs, S. Woodford, D. Woodward, C.J. Wright, Q. Xia, J. Xu, Y. Xu, M. Yeh, D. Yeum, J. Young, H.D. Zenger, W. Zha, H. Zhang, T. Zhang, Y. Zhou

Quantum Physics

Symmetry Discovery in Quantum Learning: Observable-Level and Task-Level Inference from Finite Measurements

Zeyu Chen

Symmetry reduces the capacity of a quantum learning model, but the imposed group must match both the measured information and the label transformation. We establish a finite-measurement theory for inferring this group from candidate transformations. The central structural result identifies observable-invisible transformations with the stabilizer of a projected state whenever the probe span is invariant. It turns recovered generators into a valid subgroup and identifies the continuous invisible space with its Lie algebra. For finite dictionaries, an unbiased shadow statistic distinguishes zero from positive squared expectation discrepancies with an inverse-gap measurement rate, improving the inverse-square-gap rate of uniform discrepancy estimation. A commuting qubit lower bound proves the gap dependence optimal at fixed snapshot scale, and simultaneous intervals support data-dependent tolerances. Task validation then tests either the joint distribution through a characteristic kernel or its encoded mean through a classical–quantum discrepancy. An exact group-average identity relates the latter to joint-state asymmetry and specifies its conversion to binary task breaking mass. Projection bias quantifies the cost of excessive symmetry, while an $\ell_1$ readout bound quantifies the capacity gained by relaxing it. At an invariant pure-state backbone, retained and nontrivial breaking sectors are Fisher-orthogonal. Ising-chain calculations connect finite-shot recovery, label-dependent symmetry, and physical sector drift. These results determine which symmetry the measurements support and provide the statistical and geometric basis for a subsequent release decision.
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Classical Physics · Cross-listed from cs.LG

Energy-aware frugal Bayesian optimization

Gaston Plat, Paul Saves, Nathalie Bartoli et al. (+2 more)

Modern design optimization frameworks aim first and foremost for models with the most accurate predictions without balancing computational overhead. It remains a reason why scaled architecture and multidisciplinary design optimization problems are difficult to address, even with sample-efficient Bayesian optimizers. In this paper, a metric quantifying the computational energy footprint is introduced within a Bayesian optimization framework to guide the parameter setting of a model towards configurations that balance both performance and frugality. The computer experiments highlighted existing tradeoffs between optimum convergence and the underlying energy footprint, and sometimes resulted in both a better-found optimum and lower energy consumption.
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All authors Gaston Plat, Paul Saves, Nathalie Bartoli, Thierry Lefebvre, Joseph Morlier

General Relativity and Quantum Cosmology · Cross-listed from math.MG

Monge's transport problem in synthetic Lorentzian spacetimes

Afiny Akdemir

We prove the existence of solutions to the Lorentzian Monge problem on synthetic Lorentzian spacetimes that satisfy the forward timelike measure contraction property $TMCP^+(K,N)$. The cost for this problem is the time separation function $\ell(x,y)$ (the Lorentz distance), which represents the maximum amount a particle can age when traveling from $x$ to $y$. The solution is based on the needle decomposition technique, and amounts to a reduction of the full problem to its one-dimensional counterparts. As an application of needle decomposition, we show that the Lorentzian timelike measure contraction property $TMCP^+(K,N)$ is equivalent to the $TMCP^+_{rLip}(K,N)$ condition, where the curvature dimension conditions are defined on gradient flow curves of reverse 1-Lipschitz functions.
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General Relativity and Quantum Cosmology

From Geometry to Gravity: A Friendly Introduction to the Schwarzschild Metric

Jorge Pinochet

The first exact solution to the field equations of general relativity was found by the German physicist and astronomer Karl Schwarzschild in 1916. Due to its simplicity and its various astronomical applications, the Schwarzschild solution is the most important, which gives it great educational potential. However, this potential is not usually exploited, since the Schwarzschild solution is generally taught in advanced undergraduate physics courses or in specialized graduate courses. The objective of this article is to offer a friendly introduction to the Schwarzschild solution, and at the same time analyze some concepts of Riemannian geometry and general relativity, employing only simple mathematical tools that do not go beyond the rudiments of differential and integral calculus.
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High Energy Physics (Phenomenology)

Astrophysical Signatures of Fermionic Dark Matter

Vinit D Tyagi, Suhas S S and Arun Kenath

Fermionic dark matter particles remain one of the most compelling candidates for the dark matter content of the Universe, yet no positive results have been obtained from direct detection experiments. In this work, we investigate the possibility that such particles form compact gravitationally bound objects supported by degeneracy pressure. Through an extensive review of microlensing surveys, we derive constraints on the masses of these compact objects. We further analyze the accretion of baryonic matter onto these objects and evaluate their thermal and radiative properties. The estimated burst emission is found to be well below the energies associated with the Galactic Center GeV excess, suggesting that these compact objects are unlikely to be the source of the observed signal. Our analysis suggests that admixed dark matter and baryonic matter objects could potentially account for a fraction of the presently unobserved baryonic matter, thereby providing a possible explanation for a fraction of the missing baryons in the Universe.
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General Relativity and Quantum Cosmology

First-Law Entropy and a Degenerate Extremal Remnant in a Minimal-Length Simpson–Visser-Type Regular Black Hole: Geometrothermodynamics, Phase Structure, and Observational Discriminants

T. Toghrai, N. Mansour, A. Daassou et al. (+1 more)

We construct the first-law-consistent entropy of a geometrically minimal-length-deformed Schwarzschild spacetime, obtained via the areal-radius substitution $R(r)=\sqrt{r^{2}+\ell^{2}}$ on $r\in[0,+\infty)$ with $f(R)=1-2M/R$, whose nonvanishing Einstein tensor sources an effective geometric fluid with no classical matter counterpart. Integrating the first law gives $S=\pi[r_{h}R_{h}+\ell^{2}\ln((r_{h}+R_{h})/\ell)]$. This coincides in functional form with the semiclassical term found independently by Joshi and Joshi, but we fix its boundary condition $S(r_h=0)=0$ on independent physical grounds and adopt it, rather than the Bekenstein–Hawking area law, as the complete entropy of the model, building the free energy, geometrothermodynamics, and mode-stability analysis on it. Evaporation, governed by the Helmholtz free energy $F(M)$, terminates at $M_{\min}=\ell/2$ in a previously unrecognised endpoint: a degenerate extremal regular black hole, where the regular centre coincides with a degenerate Killing horizon of quadratic order, $f\approx r^{2}/(2\ell^{2})$, at areal radius $\ell$, with $T_{H}\to 0$, $S\to 0$, $C\to 0^{+}$, and finite curvature everywhere; we display its Penrose–Carter structure for the first time. The same entropy, with $\ell$, defines the equilibrium state space of a Legendre-invariant geometrothermodynamic (GTD) description whose curvature scalar diverges independently at the Davies-type transition $M^{*}=\ell/\sqrt{2}$ and at $M_{\min}$, a divergence with no counterpart in the minimal-length black hole literature, specific to a genuine horizon at $S=0$. We embed this remnant within the observational discriminant noted qualitatively by Tsukamoto: exact shadow degeneracy combined with a measurable photon-ring flux enhancement $r_{n}=e^{-2\pi/a}>e^{-2\pi}$, accessible to next-generation very-long-baseline interferometry.
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All authors T. Toghrai, N. Mansour, A. Daassou, R. Benbrik

General Physics

Observational Constraints and Cosmic Growth Index of Realistic $f(G)$ Gravity Frameworks using MCMC Analysis

Praveen Kumar Dhankar, Munyeshyaka Albert, Mohit Thakre et al. (+3 more)

We present a comprehensive observational analysis of modified Gauss–Bonnet, or $f(G)$, gravity by investigating both the background cosmological expansion and sub-horizon linear matter perturbations. We consider two viable functional forms: an arctangent parameterization (Model~I) and a generalized polynomial power-law model (Model~II). Using a Markov Chain Monte Carlo (MCMC) ensemble sampler, we constrain their parameter spaces through background and structure-growth observations. Our analysis employs cumulative combinations of Cosmic Chronometers (CC), the Pantheon+ Type Ia Supernovae compilation (PP), Redshift-Space Distortions (RSD), and the Year-1 Baryon Acoustic Oscillation measurements from the Dark Energy Spectroscopic Instrument (DESI BAO). The inclusion of DESI BAO data produces a noticeable downward shift in the preferred values of the Hubble constant, $H_0$, and present matter density parameter, $\Omega_{m0}$. For Model~II, the full analysis yields $H_0=64.02^{+4.13}*{-3.08},\mathrm{km,s^{-1},Mpc^{-1}}$ and $\Omega*{m0}=0.249^{+0.047}_{-0.038}$. We further assess the statistical performance of the models relative to $\Lambda$CDM using $\Delta\mathrm{AIC}_c$, $\Delta\mathrm{BIC}$, and $\Delta\mathrm{DIC}$. For Model~II, the full dataset gives $\Delta\mathrm{AIC}_c=4.233$ and $\Delta\mathrm{DIC}=5.971$, favoring the $\Lambda$CDM baseline. At the perturbation level, both models exhibit stable growth histories compatible with large-scale structure observations. The models predict transitions in the late-time expansion dynamics at $z\approx0.5005$ and $z\approx0.6086$ for Models~I and II, respectively, highlighting differences in their cosmological evolution.
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All authors Praveen Kumar Dhankar, Munyeshyaka Albert, Mohit Thakre, Joseph Ntahompagaze, Safiqul Islam, Farook Rahaman

Cosmology and Nongalactic Astrophysics

CHEX-MATE: X-ray surface brightness discontinuities across a representative cluster sample

Maria Giulia Campitiello, Stefano Ettori, Lorenzo Lovisari et al. (+20 more)

We analyze the presence of X-ray surface brightness (SB) discontinuities, such as shocks and cold fronts, in the intracluster medium (ICM) of the 116 galaxy clusters from the CHEX-MATE sample. These features arise from accretion-related processes, including the merging of subclumps onto the main cluster halo and the sloshing of cold gas in a higher-entropy environment. We identify these structures in the XMM CHEX-MATE maps by examining both the SB residuals, obtained by subtracting a cluster model from the observations, and the gradient variations across X-ray images. We validate our method with an extensive analysis and comparison of the discontinuities described already in the literature. Our analysis reveals 66 discontinuities, 32 of which are newly detected, in 48 objects ($\sim$41%). We find that discontinuities in relaxed systems tend to be closer to the core, weaker, and less aligned with the global X-ray morphology compared to those in disturbed systems. Using wavelet-based temperature maps, we provide a preliminary classification of these discontinuities, proposing the occurrence of 8 putative shocks and 34 cold fronts. Furthermore, about 48% of the systems with extended radio emission show evidence of ICM discontinuities; conversely, $\sim$88% of the objects with detected discontinuities have an associated diffuse radio emission. This work also explores the limitations of using XMM data, characterized by relatively low spatial resolution, for detecting and analyzing such features, highlighting the challenges and potential biases introduced by instrumental constraints.
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All authors Maria Giulia Campitiello, Stefano Ettori, Lorenzo Lovisari, Fabio Gastaldello, Hervé Bourdin, Pasquale Mazzotta, Mariachiara Rossetti, Marco Balboni, Andrea Botteon, Rossella Cassano, Federico De Luca, Dominique Eckert, William Forman, Massimo Gaspari, Simona Ghizzardi, Myriam Gitti, Scott T. Kay, Ben J. Maughan, Etienne Pointecouteau, Gabriel W. Pratt, Elena Rasia, Jack Sayers, Mauro Sereno

Quantum Physics

Braid map definition of SLH-networks and the series product

Luc Bouten

This article investigates a cascade of quantum systems within an SLH-network. The original definition of an SLH-network depends on an open conjecture regarding the essential selfadjointness of the generator of the time evolution of the network. This problem is avoided by using the so-called braid-map, which leads to a rigorous definition of the SLH-network. An expression is derived for the time-evolution of the network with finite delay. The series product is recovered in the instantaneous feed-forward limit as a theorem that no longer depends on the conjecture.
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High Energy Physics (Experiment)

Density-Guided Conditional Neural Processes for Detector Efficiency Estimation

Yue Ma and Aobo Li

Selection efficiency connects observed counts to physical rates and rare-event search limits. With scarce calibration data, strong smoothing can erase sharp physical changes, while highly flexible models can overfit the data and mistake statistical fluctuations for physical structure. We introduce a density-guided conditional neural process (CNP) that uses spectral concentrations to control where high-frequency features are available. On MAJORANA data, it reconstructs local structure while matching measured efficiencies within twice their binomial statistical uncertainty in an average of 89% of bins across two continuum windows, versus 37% for Attentive CNP with positional encoding. With 5,000 efficiency-model training events and 500 context events, it exceeds CNP and Attentive CNP trained on twice as many events in both peak-core and continuum summaries, and also exceeds context-only KDE and Bernoulli GP. Our method thus balances the reconstruction of sharp physical features with resistance to statistical overfitting, and achieves this with fewer training events.
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Quantum Physics

Identifiability in Quantum State, Process, and Network Tomography

Athira Kalavampara Raghunadhan, Matheus Guedes De Andrade, Don Towsley et al. (+3 more)

Quantum State Tomography (QST), Quantum Process Tomography (QPT), and Quantum Network Tomography (QNT) are related parameter-estimation problems that aim to reconstruct different physical quantities. QST estimates an unknown quantum state, represented by its density matrix, from the measurement outcomes. QPT characterises an unknown quantum channel using known input states and measurements of the corresponding outputs. QNT, in contrast, aims to infer parameters associated with individual links from end-to-end probe measurements collected at accessible monitor nodes. A key distinction among the three tomography problems lies in the conditions required to achieve identifiability, the ability to determine unknown parameters uniquely from the available measurement statistics. In QST and QPT, the experimenter can choose an Informationally Complete (IC) measurement set. QNT limits the reachable measurements to what topology and monitor placement allow, so the admissible probe paths fix the information available about the link parameters. This work studies all three tomography problems through a common Fisher Information Matrix (FIM). We factorise QNT FIM and show that its rank equals the rank of the path-link incidence matrix at every interior parameter value, so local and global identifiability coincide. We then show that QST and QPT attain full rank under IC settings, QNT loses rank when the probe paths leave link parameters indistinguishable, and increasing the number of copies scales the FIM eigenvalues while leaving its rank fixed.
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All authors Athira Kalavampara Raghunadhan, Matheus Guedes De Andrade, Don Towsley, Indrakshi Dey, Daniel Kilper, Nicola Marchetti

Materials Science

Reducing the Gate-Induced Drain-Leakage Current of Carbon-Nanotube Transistors by Subliming Dispersants with Back-End-of-Line Compatible Temperature

Takumi Inaba, Yuichi Kato, Yoko Iizumi et al. (+4 more)

Carbon nanotube field-effect transistors (CNTFETs) are promising for monolithic 3D integration with silicon CMOS circuits in back-end-of-line (BEOL) processes. Further reduction in off-state leakage is essential for practical applications. In this study, we develop a low-temperature cleaning process for CNT-deposited wafers using a sublimable CNT dispersant. The process is carried out below 250 {\deg}C, making it BEOL-compatible, and does not deteriorate CNT morphology or lattice structure, as confirmed by atomic force microscopy and Raman spectroscopy. As a result, gate-induced drain leakage current originating from residual dispersants is reduced by approximately one order of magnitude. In addition, improvements in on-current, subthreshold slope, and threshold voltage variability are observed after the cleaning process. This study demonstrates a material-enabled approach to improve the transfer characteristics of CNTFETs and provides a practical route toward low-power CNT electronics.
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All authors Takumi Inaba, Yuichi Kato, Yoko Iizumi, Yasuhiko Fujita, Kazufumi Kobashi, Takahiro Morimoto, Toshiya Okazaki

Fluid Dynamics

Vertical vortex gust encounters of a delta wing

Zhecheng Liu, Kunihiko Taira and Jeff D. Eldredge

The present study analyzes encounters of a vertical vortex with a tailless NACA 0012 delta wing with a sweep angle of 60 degrees at an angle of attack of 10 degrees and Reynolds number 1000 using direct numerical simulations. Motivated by the need to fly in complex settings such as urban canyons, mountainous areas, wildfires, or vehicle swarms, we focus on the influence of a vertical vortex gust on the delta wing, complementing previous efforts that predominantly studied spanwise and streamwise vortex encounters. The vertical orientation can impose strong transient loads on all six degrees of freedom, and particular attention is devoted to connecting these loads to the flow response. By varying the gust's lateral position, size, and strength, we find a fundamental process that characterizes vertical vortex gust encounters. The gust consistently imprints a low-pressure core on the wing surface. The evolving core creates an adverse pressure gradient that distorts the baseline skin-friction pattern and induces separation that lifts the boundary layers. These lifted boundary layers are elongated and twisted by the gust's strain into lobed vortical structures, which are shown by force element analysis to make a critical contribution to the lift. As the gust's lateral position is varied from root to tip, the low-pressure core and the induced flow separation are increasingly localized around the leading edge closest to the gust, modifying the lobe evolution and leading to complex dependence of the force and moment response on gust position compared to the largely monotonic dependence on gust size and strength.
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Instrumentation and Methods for Astrophysics

Sensing ELT petal modes with a discrete beam combiner: an end-to-end theoretical model

Kalaga V. Madhav, Abani Shankar Nayak, Lucas Labadie et al. (+1 more)

The European Southern Observatory's Extremely Large Telescope (ELT), the 39-m telescope under construction in Chile, forms its entrance pupil from 798 hexagonal segments that the six 0.5-m-wide spider arms fragment into six "petals". The low-wind / island effect, adaptive-optics residuals, and mechanical drift imprint an independent piston on each petal. These differential-piston (petal) modes remain largely undetected by the ELT's baseline continuous-pupil wavefront sensors, a major bottleneck for diffraction-limited, high-contrast imaging. This paper presents a complete theoretical model of a single-mode photonic discrete beam combiner (DBC) configured to sense the six petal pistons. The model constructs the coupled-mode description of a two-dimensional evanescently coupled waveguide lattice with six inputs and forty-five outputs and derives its visibility-to-pixel matrix (V2PM); treats the pupil remapping that routes one sub-aperture per petal into the six inputs; develops the five-dimensional petal-mode basis of the fragmented pupil; and propagates the petal modes through the DBC to quantify the sensitivity. Optimising the input-port spacing and interaction length by minimising the V2PM condition number yields a well-conditioned device (CN = 10.4). It recovers petal pistons with unit linear gain over the full +/-lambda/2 (+/-800 nm) unambiguous range and separates the five modes with negligible cross-talk (< 10^-3). For 1% photometric noise, the reconstructed-piston error is 4.7 nm rms at lambda_0 = 1.6 micron. Tested against petal amplitudes from end-to-end ELT simulations (~40-300 nm rms atmospheric residual; ~0.3-1 micron low-wind events), the DBC recovers each piston to a few nm rms at H band, with a two-wavelength extension capturing the larger events. The DBC is therefore a compact, chromatically robust petalometer for the fragmented ELT pupil.
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All authors Kalaga V. Madhav, Abani Shankar Nayak, Lucas Labadie, Robert R. Thomson

Superconductivity

Disorder-driven transport in ZrN thin films grown by ion-beam-assisted sputtering

Maximo DiPreta, Samuel Jiang, Serhii Kruhlov et al. (+3 more)

We investigate the structural and electronic transport properties of zirconium nitride (ZrN) thin films grown by dc ion-beam assisted sputtering (IBAS) as a function of nitrogen partial pressure, sputtering power and deposition temperature. Variation of growth conditions enables controlled tuning from disordered metallic and superconducting behavior to insulating transport. Increasing nitrogen flow drives an increase in sheet resistance, suppression of superconducting transition temperature, and non-metallic conduction. XRD shows no measurable change in long range crystallinity or order. In the insulating regime, low-temperature transport is well described by 3D Mott variable-range hopping (VRH), with the characteristic temperature $T_0$ increasing monotonically with sheet resistance over four orders of magnitude. Despite this strong correlation between $T_0$ and disorder, $T_c$ exhibits no systematic dependence on $T_0$, indicating a decoupling between localization physics and the superconducting energy scale. Magnetotransport measurements are not well described by the standard BCS model nor the dirty type-II Werthamer-Helfand-Hohenberg model. The phase boundary is instead captured by a free-exponent power law, $\mu_0 H_{c2}(T) = \mu_0 H_{c2}(0)[1 - (T/T_c)^{n}]$ with $n \approx 3.47$, and extrapolates to $\mu_0 H_{c2}(0) \approx 6.4$ T. The films have an extracted coherence length of 7 nm. These results establish IBAS-grown ZrN as a broadly tunable platform for investigating disorder-driven transport and the crossover between metallic conduction, electronic localization, and superconductivity.
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All authors Maximo DiPreta, Samuel Jiang, Serhii Kruhlov, Yi Li, Valentine Novosad, Tomas Polakovic

High Energy Physics (Phenomenology)

Direct detection of right-handed fermionic dark matter: electron-recoil measurements in Xe atoms

Santiago Collazo, Carlos Argüelles, Soroush Shakeri et al. (+1 more)

We present theoretical estimations of the event rates for the interaction between a right-handed fermionic dark matter with an electron bound to a xenon atom. Motivated by recent astrophysical and cosmological constraints on a fermionic dark matter candidate in the sub-MeV mass range, we study such an interaction through an effective electromagnetic channel where the output consists of standard-model particles. This mechanism allows right-handed neutral dark matter fermions to couple with standard-model particles with the interchange of $W^{\pm}$ or $Z$ bosons, without the need to add extra fields. We generalize and extend previous results on this type of channels, by including for the ionization form factor arising from the interaction of the fermionic candidate with bound electrons. In addition, we compute the sensitivity curves for different direct detection experiments in such a challenging light particle mass range.
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All authors Santiago Collazo, Carlos Argüelles, Soroush Shakeri, Osvaldo Civitarese

Fluid Dynamics

A learning-based joint flow and kinematic state estimation for bodies in highly disturbed flows

Hanieh Mousavi, Anya Jones and Jeff Eldredge

Accurate estimation of unsteady aerodynamic flows from sparse measurements remains a fundamental challenge, particularly in the presence of strong disturbances, unknown body kinematics, and incomplete observations. This study presents a data-driven sequential estimation framework for joint reconstruction of unsteady flow fields, aerodynamic loads, and airfoil kinematics from sparse measurements. The approach combines a kinematics-aware nonlinear flow autoencoder with online filtering of streaming measurements. In the resulting reduced-order representation, the forecast and observation operators are learned directly from data, with each forecast-assimilation cycle requiring only a few milliseconds. The framework is evaluated on two-dimensional incompressible flow over an airfoil subjected to random vortical gusts while undergoing arbitrary pitch-up motions. Results demonstrate accurate reconstruction from surface pressure sensors, vertical lines of vorticity sensors, and synthetic velocimetry data with representative shadow regions. The transient informativeness of pressure sensors is quantified through their time-varying contributions to dominant observation modes. While lift is reconstructed from the leading modes, drag, pitch angle, and angular velocity require higher modes. Incorporating limited off-body measurements alongside surface pressure improves observability and reduces estimation error and uncertainty.
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High Energy Physics (Theory)

Electromagnetic Duality Sensitivity of Holographic Complexity

Mojtaba Shahbazi and Mehdi Sadeghi

We investigate electromagnetic duality as a diagnostic of the sensitivity of information content of holographic complexity via "complexity=anything" in Einstein-ModMax theory. Functionals constructed solely from gravitational invariants are duality invariant, whereas matter-sensitive functionals can distinguish electromagnetic configurations that share the same bulk geometry and energy-momentum tensor. As an explicit example, we consider a functional involving $F_{\mu\nu}F^{\mu\nu}$ and show that its complexity and complexity growth vary along the duality orbit, interpolating between purely electric, mixed electric-magnetic, and purely magnetic configurations. This provides an explicit realization of the freedom inherent in generalized holographic complexity and shows that different choices of complexity functional can retain different sensitivity to information about the bulk matter sector even when the gravitational geometry is insensitive to that information.
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Plasma Physics

Hydrogen and Lithium Isotope Analysis via Optical Spectroscopy of Laser-Produced Plasmas

Elizabeth Kautz, Caleb Clark, Nusrat Karim et al. (+2 more)

Accurate detection and quantification of light-element isotopes, particularly hydrogen (H) and lithium (Li), are essential across chemistry, materials science, geology, nuclear energy, forensics, and defense applications. Their isotopic compositions provide insight into fuel cycles, materials degradation, mass transport, and environmental processes. Hydrogen and Li isotopes are especially relevant in nuclear environments because neutron-induced reactions directly connect their isotopic inventories. Despite their importance, analysis of these light isotopes remains challenging due to their low atomic mass, high mobility, and, in some cases, radiological constraints. While some existing analytical techniques can detect and measure H and/or Li, they typically require extensive sample preparation, laboratory-based instrumentation, or extended analysis times that preclude real-time monitoring capabilities. To address these limitations, optical spectroscopy of laser-produced plasmas offers a promising solution, enabling field-deployable, standoff sensing of isotopic signatures with real-time analysis capability and no sample preparation requirement. This Topical Review summarizes fundamentals and recent advances in H and Li isotopic analysis using optical spectroscopy, with emphasis on laser-produced plasmas generated by laser ablation of solid targets. Key concepts relevant to isotope-resolved optical measurements are introduced, including isotope shifts, fine and hyperfine structure, and line-broadening mechanisms. Progress in optical emission, laser induced fluorescence, and absorption spectroscopy is reviewed for H and Li isotopes.
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All authors Elizabeth Kautz, Caleb Clark, Nusrat Karim, Mark C. Phillips, Sivanandan S. Harilal

Quantum Physics

An entropic characterization of Haag duality

Ruizhi Liu and Lauritz van Luijk

Motivated by Haag duality in quantum spin systems, we show that Haag duality for a pair of commuting factors generated by increasing sequences of finite-dimensional matrix algebras is equivalent to the asymptotic vanishing of a suitable conditional mutual information. For spin systems, let an annulus separate a finite region from the exterior. Haag duality then holds for a region $A$ if and only if the mutual information of the inner region and the exterior, conditioned on the part of $A$ inside the annulus, vanishes as the outer radius becomes large. As a corollary, assuming a strict area law with subleading corrections, Haag duality holds for single cones, and it holds for unions of two or more disjoint cones precisely when the topological entanglement entropy vanishes. For translation-invariant pure states on spin chains, half-chain Haag duality is equivalent to vanishing entropy density.
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Quantum Physics

Practical Considerations for Processing Massive Classical Data via Quantum Oracle Sketching

Stefano Markidis

Classical-to-quantum I/O is a critical bottleneck for data-intensive quantum workloads. Quantum Oracle Sketching (QOS) has been proposed to address this problem. We identify its practical requirements, including the representation of data as a probability distribution over oracle addresses, the relation between sample count, approximation error, and update cost, and the coherence and runtime support required for online execution. To study QOS on current quantum computing devices, we develop an offline realization that compiles sample blocks into empirical phase oracles and evaluate it using DNA fingerprinting. The application converges with relatively few samples, while exact phase fusion combines repeated updates to the same address. However, the compiled circuits remain too deep for current quantum computing devices. Practical QOS therefore requires lower depth oracle synthesis and interactive quantum runtimes.
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Quantum Physics

WISER: Systematic Design-Space Exploration of Trapped Ions with Multiplexed Control

Scott Jones, Song-qing-hao Yang and Prakash Murali

Trapped-ion Quantum Charge-Coupled Devices (QCCD) are a leading contender for quantum computing, but their scalability is constrained by control wiring and electronics. Wiring using Integrated Switching Electronics (WISE), a recently proposed QCCD architecture, reduces wiring through multiplexing and integrated switching hardware. However, this leaves an execution model with limited parallelism and limited flexibility in ion movement. Further, these devices need to be paired with a quantum error correction (QEC) code to enable fault-tolerant quantum computation (FTQC). Can WISE architectures efficiently support FTQC requirements? Which QEC choices, device and control parameters are practical? We present WISER, a cross-layer design-space exploration framework for trapped-ion systems with multiplexed control. WISER combines a WISE-specific SAT-based compiler, a physics-informed noise model and logical-memory simulation to estimate logical error rates, logical clock speeds and control power across hardware parameters and QEC families. Its compiler reduces routing time by $2.6$–$18.8\times$ relative to a greedy WISE-compatible baseline. Our analysis provides concrete design guidance. Two-ion traps with $16$-way multiplexing, $8\times$ lower than the original WISE proposal, give the fastest logical clock that meets our reliability and cold-stage power targets. With current hardware parameters, the distance-7 surface code is the only evaluated code to meet our early-FTQC screen, at $4.58\,$Hz and $2.04\,$W of DAC power per logical qubit. At this operating point, ion transport and recooling take $94$–$96\%$ of the WISE cycle, and even without them sample-and-hold electrode charging leaves millisecond-scale syndrome-extraction rounds.
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Materials Science

Local Response Theory of Electrified Interfaces from Screened Effective Charges

Nicolas G. Hörmann, Nicolas Bergmann and Karsten Reuter

First-principles, electronic-structure simulations provide direct access to ground-state, global system properties. In the context of computational electrochemistry these are, e.g., bias-dependent energies, free energies, work functions, and capacitances. However, a comparably systematic local description of how these quantities respond to biasing via interfacial charging is still missing. Here, we introduce the screened electrochemical Born effective charge (SEBEC), a mixed total-energy derivative that measures the force response of an atomic degree of freedom to interfacial charging under electrochemical boundary conditions. SEBECs play the role for electrochemistry that Born effective charges play in the modern theory of polarization: they provide an unambiguous decomposition of global response and generate the same formal structures for structural relaxation, capacitance, and electrochemical Stark tuning that are familiar from solid-state response theory. The broader implication is a local response framework that brings electrochemical interfaces closer to the conceptual rigor long established for insulating solids.
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Materials Science

Slow Thermalization and Long-Lived Coherence across Acoustic Phonon Branches in BAs

Zeyu Xiang, Ying Peng, Ange Benise Niyikiza et al. (+11 more)

The exceptionally high thermal conductivity of cubic boron arsenide (BAs) arises from suppressed three-phonon scattering associated with its large acoustic–optical gap. In this regime, four-phonon processes become non-negligible, creating an unusual scattering hierarchy with unexplored consequences for nonequilibrium phonon dynamics. Here, time-resolved x-ray diffuse scattering reveals exceptionally slow, branch-dependent acoustic phonon thermalization and long-lived coherence. Exploiting branch sensitivity in one-phonon diffuse scattering, we resolve transverse acoustic (TA) and longitudinal acoustic (LA) thermalization times of 29.2 and 13.9~ps, respectively; even the LA timescale is at least three times that in common semiconductors. Phonon dispersion calculations assign coherent oscillations at 0.19 and 0.27~THz to the TA and LA modes, respectively; both persist with little decay over 50~ps, with comparable coherence found only in diamond. These findings provide a direct dynamical manifestation of the weak phonon scattering underlying the exceptional thermal transport of BAs.
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All authors Zeyu Xiang, Ying Peng, Ange Benise Niyikiza, Fanghao Zhang, Haoyuan Li, Takahiro Sato, Thomas Linker, Yanwen Sun, Meredith Henstridge, Vincent Esposito, James F. Cotter, Diling Zhu, Zhifeng Ren, Bolin Liao

High Energy Astrophysical Phenomena

Observable Signatures of Supernova Shock Breakout in Confined Circumstellar Medium

Wun-Yi Chen, Ke-Jung Chen, Keiichi Maeda et al. (+1 more)

Supernova shock breakout encodes rich information about stellar explosions, including the properties of the progenitor, the explosion mechanism, and the circumstellar environment. We present the first two-dimensional multigroup radiation-hydrodynamic simulations of shock breakout from Red Supergiant (RSG) progenitor stars embedded in confined circumstellar medium (CSM) produced shortly before core collapse. Our simulations reveal that radiation escaping ahead of the shock forms a radiative precursor that modifies the shock dynamics, drives multidimensional mixing within the radiating gas layers, and alters the emergent radiation from the CSM. For the CSM models explored here, the resulting bolometric light curves reach peak luminosities of ${\sim}1\text{-}3 \times 10^{44}\ \mathrm{erg\ s^{-1}}$ with durations of ${\sim}4\text{-}35$~hr, with these signatures controlled by the CSM mass and the confined radius. Our multi-wavelength calculations further reveal a pronounced extreme-ultraviolet emission, where ionizing photons of energies ${\ge}54.4$~eV can sustain flash-ionized He II and power strong emission from its recombination line of $\lambda 4686\ \mathring{A}$. Furthermore, we identify diagnostic signatures of shock breakout with dense CSM and assess their detectability with Einstein Probe and ULTRASAT. Our models and predictions provide promising diagnostics of shock breakout in CSM that may be detectable by current and forthcoming high-cadence ultraviolet and X-ray space telescopes.
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All authors Wun-Yi Chen, Ke-Jung Chen, Keiichi Maeda, Friedrich K. Röpke