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Thursday 11 June

Chemical Physics

Orbital-optimized density functional calculations of excited electronic states: Recent advances and perspectives

Lorenzo Restaino, Giulia Gamboni, Elli Selenius et al. (+1 more)

Orbital-optimized (OO) density functional calculations provide a time-independent, variational route to electronic excitations, alternative to presently widely used time-dependent density functional theory (TDDFT) approaches. As the orbitals are optimized in a state specific way, these methods can provide a balanced description of excited states with different character, thereby overcoming several limitations of practical implementations of TDDFT. Driven by recent developments in algorithms for obtaining excited states as saddle points on the electronic energy surface, OO methods have attracted increasing interest, maturing into an active and rapidly expanding area of research. Here, the theoretical foundations of the approach are clarified and an overview of recent methodological developments in excited-state orbital optimization is provided. An overview of methods for treating open-shell singlet excited states and current approaches for computing transition properties and spectra is also provided. Finally, recent applications to molecular Rydberg, charge-transfer, and core excitations are reviewed, with the aim of assessing the present accuracy and range of applicability of OO density functional calculations with common exchange and correlation functionals.
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All authors Lorenzo Restaino, Giulia Gamboni, Elli Selenius, Gianluca Levi

Mathematical Physics · Cross-listed from math.CO

A local bijection between alternating sign matrices and descending plane partitions and a Striker–Fulmek-type $q$-statistic

Michael J. Schlosser

We prove a local bijection between alternating sign matrices (ASMs) and descending plane partitions (DPPs) in the refined fibres of Behrend–Di Francesco–Zinn-Justin. The map is constructed by moving a boundary line through the ASM and DPP pictures. At each step only a bounded neighbourhood of that boundary is changed. In growth-diagram language, the boundary states are ordinary ASM row frontiers and shifted DPP path frontiers, and the elementary moves are reversible Fomin-type square rules. The proof checks that overlapping local moves are confluent, that every square is invertible, and that the completed boundary again satisfies the ordinary ASM and DPP coordinate inequalities. The only terminal choice is resolved by a radius-two fan rule on the visible height contour. The same local framework gives a statistic on refined ASMs whose generating function is the DPP degree enumerator. The statistic has a Striker–Fulmek quadratic core \[ Q_{\rm SF}(A)= \sum_{1\le r<s\le n}\ \sum_{1\le b<a\le n} (n-r+1)A_{r,a}A_{s,b}, \] plus a bounded fan-boundary correction and, outside the normal boundary gauge, an explicit compact-potential endpoint term. In the normal gauge this is \[ W_{\rm ASM}^{\rm SF}(A)=Q_{\rm SF}(A)+B_{\rm fan}(A). \] Thus the paper gives both a local ASM–DPP bijection and a statistic-preserving refined \(q\)-enumeration. The supplementary files reproduce selected local checks and the displayed arithmetic examples.
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2606.13653 · 11 Jun · Withdrawn by the author because the present manuscript does not provide a complete, human-verifiable proof of the claimed ASM-DPP bijection. Several essential all-order steps remain insufficiently justified, and the main theorem should therefore not be regarded as established. A substantially revised version may be posted when these issues have been resolved

Abstract PDF $MTRX ×2$LANG ×1

Mesoscale and Nanoscale Physics

Engineering electrically-switchable quantum anomalous Hall states by spin-orbit coupling

Maosen Qin, Ziwei Wang, Gyeongmin Kim et al. (+5 more)

Nonvolatile gate-driven switching of quantum anomalous Hall (QAH) states in graphene moiré systems provides a promising route toward topological electronics based on chiral edge states. However, deliberate use of this switching mechanism requires control over both the magnetic properties and metastability of QAH states. While previous demonstrations mostly relied on the intrinsic magnetic energy landscape of moiré devices, here we show that this landscape can be engineered through proximity coupling to WSe2. We find that proximitizing twisted monolayer-bilayer graphene by WSe2 reshapes the magnetization reversals responsible for nonvolatile electrical switching of QAH states. We attribute this effect to the proximity-induced spin-orbit coupling (SOC), which can lock spin and valley and modify the magnetization of the competing states involved in switching compared with non-proximitized graphene systems. Our findings establish proximity-induced SOC as a new way to engineer magnetic properties and switchable magnetic states in graphene-based systems. We further demonstrate that strong magnetic metastability in tMBG allows the magnetic states to be gate-tuned between QAH and metallic regimes, and between QAH states with Chern numbers |C| = 2 and 1 without resetting the magnetic state. This functionality points toward new device architectures based on QAH chiral edge states.
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All authors Maosen Qin, Ziwei Wang, Gyeongmin Kim, Kenji Watanabe, Takashi Taniguchi, Steven H. Simon, Siddharth A. Parameswaran, Hryhoriy Polshyn

Quantum Physics

To Cool, or Not to Cool? Displacement Sensing with Hot Quantum States

Piotr T. Grochowski

Quantum-enhanced displacement sensing with bosonic systems is typically formulated assuming that the oscillator is cooled close to its ground state before nonclassical probe preparation. We investigate whether such near-ground-state initialization is necessary, or whether sensitive probes can instead be generated directly from thermal states. We analyze hot quantum probes produced by squeezing, number-raising, and Schrödinger-cat-state generation applied to thermal inputs. We identify two distinct mechanisms by which thermal mixedness can remain compatible with enhanced displacement sensitivity. First, projecting a mixed probe onto a definite parity sector removes the usual thermal suppression of the displacement quantum Fisher information, which can then increase with initial thermal occupation. Second, coherent superpositions of opposite displacements can retain sensitivity through coherence between their displaced components, even when the underlying state is mixed. We use these two mechanisms to classify hot-state protocols according to whether their sensitivity comes from parity selection, coherence between displaced components, or both. Finally, we formulate an experimentally relevant optimization problem comparing initial cooling with direct hot-state preparation under realistic decoherence and show that complete cooling is not universally optimal. Our results establish hot-state engineering as a route to quantum-enhanced bosonic displacement sensing without mandatory ground-state initialization.
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Nuclear Theory

Observable Dependence of Viscous Corrections in QGP: Heavy Quarks and Dileptons in Chapman–Enskog Theory

Lakshmi J. Naik, P. Parvathi, Nachiketa Sarkar et al. (+1 more)

We calculate, for the first time, heavy quark transport and thermal dilepton production from QGP using viscous correction up to second order in gradients. We use the form of viscous correction obtained from Chapman-Enskog like expansion of the Boltzmann transport equation in relaxation time approximation, and compare our results with that of Grad's 14-moment approximation. By employing the temperature and shear stress evolution profiles of QGP obtained from second-order causal relativistic viscous hydrodynamics, we study the heavy quark transport coefficients and thermal dilepton production from an evolving QGP. In the case of HQ transport, the CE corrections suppress the drag force substantially, induce a non-trivial momentum dependence in transverse momentum diffusion, and result in a comparatively less modification in longitudinal momentum diffusion. Whereas, for thermal dileptons, the CE corrections result in an enhanced early-time contribution which decreases and become converging to the first-order CE correction with the evolution of QGP, and remain well behaved compared to that of Grad's correction. Our results indicate that the modification of the observable due to viscous corrections is governed by the magnitude of the corrections as well as the interplay between their momentum dependence and momentum weighting of the transport and emission kernels. We demonstrate that the momentum structure of the various viscous corrections at the level of distribution function is not directly translated to the observables since the different observables are sensitive to distinct regions of momentum space.
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All authors Lakshmi J. Naik, P. Parvathi, Nachiketa Sarkar, V. Sreekanth

Quantum Gases

Driven dynamics of an attractive Bose polaron

Saptarshi Majumdar and Aleksandra Petković

We study the out-of-equilibrium dynamics of an impurity driven by a constant external force through a system of homogeneous weakly-interacting bosons in one spatial dimension. The impurity-boson interaction is assumed to be attractive. We show that the impurity exhibits drifted Bloch oscillations in a wide range of forces in the absence of a lattice. We characterize the dynamical response of the host bosons and explain the mechanism underlying the Bloch oscillations. We analyse the behavior of the drift velocity, the Bloch amplitude and the time period of oscillations in a wide range of forces and other system parameters. In contrast to the case of repulsive impurity-boson interaction, the drift velocity exhibits a sub-linear dependence on a weak applied force, $V_d\sim {F}^{\alpha}$ with a positive exponent $\alpha$ smaller than unity. The drift velocity monotonically increases with force, though the scaling behavior varies considerably across different regimes of $F$. Moreover, the amplitude of the velocity oscillations displays rich behavior: it first undergoes a decay with force, reaches a minimum, and then presents a revival, increasing with force.
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General Relativity and Quantum Cosmology

Search for High-Frequency Gravitational Waves via Geomagnetic Conversion with Radio Telescopes

Hongliang Tian, Lei Wu, Xiaolong Yang et al. (+2 more)

The detection of high-frequency gravitational waves (HFGWs) above 10 kHz provides a crucial probe of exotic astrophysical phenomena and new physics. We report the first search for HFGWs via their conversion to electromagnetic radiation through the inverse Gertsenshtein effect in Earth's magnetic field, utilizing radio telescopes including the Very Large Array (VLA) and the Atacama Large Millimeter/submillimeter Array (ALMA). Since no statistically significant signal is observed, we obtain new upper limits on the characteristic strain across the 1 GHz – 1 THz band, with the most stringent constraint reaching $h_c \lesssim 10^{-18}$, improving upon existing bounds by up to three orders of magnitude. These results significantly advance the exploration of uncharted parameter space for exotic gravitational-wave sources, paving the way for future discoveries with next-generation facilities such as the Square Kilometre Array (SKA).
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All authors Hongliang Tian, Lei Wu, Xiaolong Yang, Qiang Yuan, Bin Zhu

Quantum Physics

Generalized two-qubit Hamiltonian for Projective Quantum Feature Maps

Rafael Simões do Carmo, Edson Amaro Junior and Felipe Fanchini

Projected quantum feature maps provide a strategy for using quantum processors as feature generators for classical machine-learning models. Building on counterdiabatic Ising-glass and one-dimensional Heisenberg PQFMs, we introduce a generalized two-qubit Hamiltonian-based PQFM that provides a unified way to encode classical features through local Pauli fields and pairwise two-qubit Pauli interactions. This construction allows distinct classical variables to be embedded along different Pauli axes of the same qubit, increasing the information density of shallow circuits while remaining compatible with hardware constraints. We develop and implement these methods in pqfmlib, a publicly available Python library for constructing, executing, and benchmarking Hamiltonian-based PQFMs.We then benchmark the generalized Hamiltonian PQFMs against reference PQFMs on four biomedical classification datasets under a nested cross-validation protocol with paired statistical tests. Quantum features are generated using both IBM quantum processors with up to 156 qubits and statevector simulations. Our results show that the generalized two-qubit Hamiltonian family provides the most consistent pattern of statistically supported gains over matched classical baselines, although the performance of all methods depends on the dataset, encoding strategy, measured observables, and hardware conditions. These findings support generalized Hamiltonian PQFMs as a promising route toward near-term quantum utility.
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Quantum Physics

Optimal classical shadow estimation of unitary channels at Heisenberg limit

Entong He, Zihao Li, Noam Scully et al. (+2 more)

Full tomography of an unknown quantum evolution is resource-intensive and often unnecessary when the goal is only to predict selected properties. This motivates the study of classical shadow estimation of unitary channels (CSEU), a task in which one queries an unknown $d$-dimensional unitary $U$ and stores classical data that can later be used to predict expectation values $\mathrm{tr}[O U\rho U^\dagger]$ for arbitrary input states $\rho$ and observables $O$. Here we propose a parallel and non-adaptive CSEU protocol that uses $\mathcal{O}(\min\{d\varepsilon^{-2},d^{3/2}\varepsilon^{-1}\})$ queries to $U$ when the observables have constant effective size. This achieves Heisenberg scaling with respect to the additive error $\varepsilon$ and is query-optimal, as we prove a matching lower bound $\Omega(\min\{d\varepsilon^{-2},d^{3/2}\varepsilon^{-1}\})$ for the query complexity, which remains valid even when stronger access to the unknown unitary is available. Our CSEU protocol is a versatile primitive with applications to several quantum learning tasks. In particular, it yields a near-optimal algorithm for learning an arbitrary Hamiltonian from its real-time evolution in the high-precision regime and recovers the best-known bounds for several tasks in a unified way.
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All authors Entong He, Zihao Li, Noam Scully, Sisi Zhou, Yuxiang Yang

General Relativity and Quantum Cosmology

Hierarchical formulation of the self-gravitating, n-dimensional, charged scalar field in spherical symmetry in affine null formalism

Laura Bridera, Emanuel Gallo and Thomas Mädler

We develop an affine-null characteristic formulation of the Einstein-Maxwell system coupled to a charged complex scalar field in $n$-dimensional spherical symmetry. By introducing suitable auxiliary variables, the main field equations are cast into a hierarchical system of radial hypersurface equations, supplemented by a transport equation for the scalar field. We discuss the associated characteristic initial-boundary value problem for asymptotic, vertex and null-boundary configurations, and derive the corresponding asymptotic quantities and balance laws. As a consistency check, we recover the scalar-free Reissner-Nordström-Tangherlini family, including both the non-extremal and extremal branches, directly from the hierarchy. The resulting framework provides a systematic setting for the study of charged scalar dynamics and exact black-hole solutions in higher-dimensional affine-null coordinates.
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General Relativity and Quantum Cosmology

Geometrically Regular Black Object Solutions in Lower-Dimensional Gauss-Bonnet Gravity and Its Unimodular Extension

G. Alencar, T. M. Crispim and C. R. Muniz

We investigate the construction of regular compact objects in the recently proposed lower-dimensional Einstein–Gauss–Bonnet (EGB) gravity obtained through regularized dimensional reduction. Unlike the standard BTZ black hole, the corresponding vacuum EGB solution develops a genuine curvature singularity at the origin, providing an interesting setting in which higher-curvature corrections deteriorate the ultraviolet behavior of spacetime. To address this issue, we reconstruct matter sectors capable of restoring regularity while preserving the BTZ-like asymptotic structure. First, we derive regular black-hole solutions supported by nonlinear electrodynamics and determine the corresponding electromagnetic Lagrangians directly from the field equations. We then extend the analysis to Simpson–Visser black-bounce geometries, obtaining smooth throat configurations with finite curvature invariants throughout the spacetime. As an alternative regularization mechanism, we formulate a unimodular extension of lower-dimensional EGB gravity and show that standard Maxwell fields can support regular geometries through a dynamical exchange between the vacuum and matter sectors mediated by a spacetime-dependent cosmological function. We further investigate the thermodynamic properties of the regular black-hole and black-bounce solutions, showing that the matter sector modifies the evaporation process, allows for remnant formation, and produces nontrivial phase transitions. In the black-bounce case, the thermodynamic quantities smoothly recover the EGB-BTZ behavior in the appropriate limit. These results demonstrate that lower-dimensional EGB gravity provides a useful laboratory for exploring the interplay between higher-curvature corrections, regular compact objects, nonlinear electrodynamics, and unimodular gravity.
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High Energy Physics (Theory)

A Graphical Coaction for FRW Integrals from Partial/Relative Twisted (Co)homology

Andrew J. McLeod, Andrzej Pokraka and Lecheng Ren

We construct a graphical coaction for Friedmann-Robertson-Walker (FRW) integrals at all loop orders in conformally-coupled scalar theories with non-conformal polynomial interactions. Our construction makes use of intersection theory in the context of (partial/relative) twisted (co)homology, which we use to decompose FRW integrals (and their discontinuities and derivatives) into building blocks that can be represented as decorations of the original Feynman diagram. This facilitates a purely graphical description of the coaction, up to rational prefactors that can be read off from the graph. Our construction provides a comprehensive combinatorial framework for dissecting the analytic properties of cosmological observables; in particular, we demonstrate that the combinatorics of the differential equations that govern FRW integrals – their so-called kinematic flow – is a natural consequence of our coaction. We have also developed a user-friendly web application that computes the graphical coaction of any graph: https://frwcoaction.ca. Whenever possible, the web application also computes the differentials and discontinuities. A Mathematica notebook with the same functionality is also hosted at on a public GitHub repository.
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Optics

Electric-Field Mapping of Optically Perturbed CdTe Radiation Detectors

Adriano Cola, Lorenzo Dominici and Antonio Valletta

In radiation detectors, the spatial distribution of the electric field plays a fundamental role in their operation. Access to this field distribution is of strategic importance, especially when investigating the perturbing effects induced by incident radiation. For example, one dangerous effect that prevents their proper operation is the accumulation of internal space charge. Here, we probe the two-dimensional electric field in a Schottky CdTe detector using the Pockels effect and report on its local perturbation after exposure to an optical beam at the anode electrode. Our electro-optical imaging setup, together with a custom processing routine, allows the extraction of the electric-field vector maps and their dynamics during a voltage bias-optical exposure sequence. The results are in agreement with numerical simulations, allowing us to confirm a two-level model based on a dominant deep level. Such a simple model is indeed able to fully account for both the temporal and spatial dynamics of the perturbed electric field. This approach thus allows a deeper understanding of the main mechanisms affecting the non-equilibrium electric-field distribution in CdTe Schottky detectors, such as those leading to polarization. In the future, it could also be used to predict and improve the performance of planar or electrode-segmented detectors.
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Soft Condensed Matter

Geometric formulation of state-dependent Langevin dynamics using scalar free energy

Kento Yasuda, Zhongqiang Xiong, Zhanglin Hou et al. (+3 more)

Stochastic dynamics with state-dependent diffusion arise broadly in confined, anisotropic, and hydrodynamically coupled systems. The conventional Langevin equation contains a spurious drift associated with multiplicative noise. Since the restricted free energy is generally non-scalar, the covariance is not explicit. Here, we reformulate state-dependent Langevin dynamics using a scalar free energy and a diffusion metric defined by the inverse diffusion tensor. The conventional spurious drift is then expressed as a Christoffel contribution. Although our formulation is mathematically equivalent to the conventional one through the relation between the restricted and scalar free energies, it makes coordinate covariance explicit and enables the phenomenological construction of thermodynamic potentials directly from system symmetries. We demonstrate its consistency in representative examples of state-dependent diffusion arising from coordinate transformations, geometric confinement, and projection from curved to flat spaces.
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All authors Kento Yasuda, Zhongqiang Xiong, Zhanglin Hou, Kenta Ishimoto, Xinpeng Xu, Shigeyuki Komura

High Energy Physics (Experiment)

First Measurement of Sub-GeV $\nu_{\mu}$ Charged-Current Coherent Pion Production on Argon in MicroBooNE

MicroBooNE collaboration: P. Abratenko, D. Andrade Aldana, J. Asaadi et al. (+188 more)

We report a measurement of the charged-current coherent pion production cross section on argon using the MicroBooNE liquid argon time projection chamber exposed to the Booster Neutrino Beam at Fermilab. The measurement uses the MicroBooNE data set corresponding to $1.26 \times 10^{21}$ protons on target with a mean neutrino energy of $0.8$~GeV. The flux-averaged cross section is measured to be $(9.1 \pm 1.2_{\text{stat}} \pm 1.2_\text{syst}) \times 10^{-40}\,\text{cm}^2/\text{Ar}$. This result represents the first measurement of charged-current coherent pion production on argon at sub-GeV neutrino energies. Due to its clean two-body kinematics, where the neutrino interacts coherently with the entire nucleus producing a forward muon and pion with no nuclear breakup, this process provides a useful tool for constraining neutrino flux uncertainties in current and future oscillation experiments such as DUNE.
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All authors MicroBooNE collaboration: P. Abratenko, D. Andrade Aldana, J. Asaadi, A. Ashkenazi, S. Balasubramanian, B. Baller, A. Barnard, G. Barr, D. Barrow, J. Barrow, V. Basque, J. Bateman, B. Behera, O. Benevides Rodrigues, S. Berkman, A. Bhat, M. Bhattacharya, V. Bhelande, A. Binau, M. Bishai, A. Blake, B. Bogart, T. Bolton, M.B. Brunetti, L. Camilleri, D. Caratelli, F. Cavanna, G. Cerati, A. Chappell, Y. Chen, J.M. Conrad, M. Convery, L. Cooper-Troendle, J.I. Crespo-Anadon, R. Cross, M. Del Tutto, S.R. Dennis, P. Detje, R. Diurba, Z. Djurcic, K. Duffy, S. Dytman, B. Eberly, P. Englezos, A. Ereditato, J.J. Evans, C. Fang, B.T. Fleming, W. Foreman, D. Franco, A.P. Furmanski, F. Gao, D. Garcia-Gamez, S. Gardiner, G. Ge, S. Gollapinni, E. Gramellini, P. Green, H. Greenlee, L. Gu, W. Gu, R. Guenette, L. Hagaman, M. D. Handley, O. Hen, A. Hergenhan, M. Harrison, S. Hawkins, C. Hilgenberg, G.A. Horton-Smith, A. Hussain, B. Irwin, M.S. Ismail, C. James, X. Ji, J.H. Jo, A. Johnson, R.A. Johnson, D. Kalra, G. Karagiorgi, W. Ketchum, A. Kelly, M. Kirby, T. Kobilarcik, K. Kumar, N. Lane, J.-Y. Li, Y. Li, K. Lin, B.R. Littlejohn, L. Liu, S. Liu, W.C. Louis, X. Luo, T. Mahmud, N. Majeed, C. Mariani, J. Marshall, D.A. Martinez Caicedo, F. Martinez Lopez, M. G. Manuel Alves, S. Martynenko, A. Mastbaum, I. Mawby, N. McConkey, B. McConnell, L. Mellet, J. Mendez, J. Micallef, T. Mohayai, A. Mogan, M. Mooney, A.F. Moor, C.D. Moore, L. Mora Lepin, M. A. Hernandez Morquecho, M.M. Moudgalya, S. Mulleria Babu, D. Naples, A. Navrer-Agasson, N. Nayak, M. Nebot-Guinot, C. Nguyen, L. Nguyen, J. Nowak, N. Oza, O. Palamara, N. Pallat, V. Paolone, A. Papadopoulou, V. Papavassiliou, H. Parkinson, S.F. Pate, N. Patel, Z. Pavlovic, E. Piasetzky, K. Pletcher, I. Pophale, X. Qian, J.L. Raaf, V. Radeka, A. Rafique, M. Reggiani-Guzzo, J. Rodriguez Rondon, M. Rosenberg, M. Ross-Lonergan, I. Safa, C. Sauer, D.W. Schmitz, A. Schukraft, W. Seligman, M.H. Shaevitz, R. Sharankova, J. Shi, L. Silva, E.L. Snider, S. Soldner-Rembold, J. Spitz, M. Stancari, J. St. John, T. Strauss, A.M. Szelc, N. Taniuchi, K. Terao, C.Thorpe, D. Torbunov, D. Totani, M. Toups, A. Trettin, Y.-T. Tsai, J. Tyler, M.A. Uchida, T. Usher, B. Viren, J. Wang, L. Wang, M. Weber, H. Wei, A.J. White, S. Wolbers, T. Wongjirad, K. Wresilo, W. Wu, E. Yandel, T. Yang, L.E. Yates, H.W. Yu, G.P. Zeller, J. Zennamo, C. Zhang, Y. Zhang

High Energy Physics (Theory)

Cosmological Dynamics of the Thermal Scalar Near the Hagedorn Temperature

Arnab Pradhan, Luis Rufino and Scott Watson

We study the cosmological dynamics of the thermal scalar the winding string mode that becomes massless at the Hagedorn transition by coupling it to the string-frame gravi dilaton effective action. This provides a field-theoretic framework for investigating winding mode dynamics near the Hagedorn temperature and their role in string cosmology. Below the Hagedorn temperature, the phase space contains static configurations in which the thermal scalar balances the shifted dilaton evolution. These configurations are boundary states rather than attractors, and when the thermal scalar mass depends on the scale factor, winding mode back reaction opposes expansion and can reverse it. Above the Hagedorn temperature, the tachyonic thermal scalar generates negative effective energy density while preserving the null energy condition, enabling branch changes of the Brustein Veneziano type. These transitions do not provide the graceful exit required to connect the Hagedorn phase to standard cosmological evolution. At the Hagedorn temperature itself, the quadratic effective theory breaks down and higher order interactions become essential. Because the thermal scalar originates as a Euclidean order parameter, our Lorentzian treatment should be viewed as an effective dynamical model of the Hagedorn transition. Within this framework, the thermal scalar clarifies the dynamical structure surrounding the Hagedorn transition and shows how the Hagedorn exit problem cannot be resolved within the quadratic effective theory alone.
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Optics

Temporal glide symmetry enforces a parity sideband selection rule in scalar bulk media

Miguel Camacho

Symmetry is a powerful way to control coupling between photonic mode families. In spatially periodic structures, glide symmetry can protect band contacts and suppress stop bands. Here we show a different role for temporal glide, a spatiotemporal counterpart combining reflection with a half-period time translation. In a scalar time-modulated trilayer waveguide, temporal glide imposes an exact selection rule linking frequency conversion to transverse-mode symmetry: the parity content of every Floquet eigenstate alternates with sideband index, up to a state-dependent sign. In scattering, this means that a mode of definite parity can emit only into the opposite transverse parity at odd sidebands and into the same parity at even sidebands. We verify the rule directly in bulk Floquet eigenstates and in finite-section time-domain simulations. An incident odd waveguide mode is converted into an even frequency sideband, while all symmetry-forbidden output channels at the analysed sidebands are suppressed to numerically negligible values. Rather than acting as a temporal copy of spatial-glide band sticking, temporal glide provides a distinct symmetry principle for converting electromagnetic energy between selected modes and frequencies.
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Quantum Physics

Diffusive Dynamics of Nonstabilizerness

Zhenyu Xiao and Shinsei Ryu

Symmetries shape the quantum-information dynamics of many-body systems, but their effect on nonstabilizerness, the resource complementary to entanglement, is less understood. We compute the stabilizer Rényi entropy, a measure of nonstabilizerness, in $\mathrm{U}(1)$-symmetric one-dimensional random circuits. The disorder-averaged dynamics is captured by a four-replica tensor network, which we evaluate by $S_4$-adapted infinite time-evolving block decimation (iTEBD) directly in the thermodynamic limit. Together with a hydrodynamic argument, our results identify a diffusive universality class for the late-time approach of nonstabilizerness to its random-state value, with the stabilizer Rényi entropy gap closing as $1/t$. The same scaling is verified in an energy-conserving nonintegrable Ising chain. More broadly, our framework provides a hydrodynamic perspective on nonstabilizerness generation and offers insight into the design of approximate Haar-random states in Hamiltonian dynamics.
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Instrumentation and Methods for Astrophysics

Feasibility of up-the-ramp sampling under variable sky for ground-based spectrographs

Gaia Gaspar, Marcin Sawicki, Nelson Nunes et al. (+2 more)

Many modern near-infrared instruments employ HAWAII-2RG (H2RG) detectors with integration times that can reach 300-600s. Up-the-ramp (UTR) sampling offers advantages over Fowler sampling, including superior cosmic ray rejection and noise reduction, but requires fitting linear ramps from 30-60 reads. Ground-based K-band sky brightness has been reported to vary by 3-10% on timescales of minutes, potentially introducing systematic errors and compromising photometric accuracy. Additionally, UTR data formats involve higher-dimensional FITS files with larger file sizes impacting observatory operations. We present a feasibility study using the GIRMOS Data Simulator with high-fidelity flux budgets and empirical K-band sky variations estimated, for Mauna Kea, from Gemini-NIRI at 10-20s cadence. Using a Monte Carlo approach we assess whether linear ramp fitting remains viable under variable sky conditions, quantify SNRs and systematic biases, and report nightly data volume estimates. Our results show that, in the H-band, the advantages of the UTR readout hold for read-noise-limited targets placed in the inter-line regions, translating into 3-4% savings in observing time. The K-band inter-line regions do not show significant SNR improvement and can even degrade it due to the dominance of shot-noise generated by the thermal emission of the instrument+telescope system. In these regions, cosmic ray rejection recovers $>$ 98% of events with false positive rates below 0.1%, even under high sky variability. Over the sky emission lines, UTR fitting remains possible but its performance is compromised, both by a degradation in SNR and by a high rate of pixels falsely flagged by the cosmic ray rejection algorithm under highly variable sky. These findings address how ground-based conditions affect UTR implementation in near-infrared spectrographs, with GIRMOS as a concrete case of study.
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All authors Gaia Gaspar, Marcin Sawicki, Nelson Nunes, Rubén J. Díaz, James E. H. Turner

High Energy Physics (Theory)

Black Hole Thermodynamics Meets On-Shell Amplitudes: Local Detailed Balance and Thermal Spectrum from Spin Universality and Unitarity

Dogan Akpinar, Katsuki Aoki, Andrea Cristofoli et al. (+2 more)

We develop an on-shell framework for thermal dissipation and radiation by macroscopic objects, whose large degeneracy of internal states is encoded in their entropy. In this framework, equilibrium asymptotic states are represented as on-shell particles, while non-equilibrium processes are described by on-shell transition amplitudes between them. A central observation is that spinning states remain essential even for macroscopically non-rotating objects. Consistency with macroscopic symmetries then implies spin universality, whereby all spinning states are governed by a single universal coupling. A key consequence is that absorption and emission probabilities are controlled by the same coupling, yielding local detailed balance directly from on-shell data. Applied to black holes, our framework reproduces the thermal emission spectrum and relates the Hawking temperature to the condition of maximal absorption consistent with unitary time evolution.
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All authors Dogan Akpinar, Katsuki Aoki, Andrea Cristofoli, Hyun Jeong, Kaho Yoshimura

High Energy Physics (Phenomenology)

Natural Supercooling and Reheating along Supersymmetric Flat Directions and Observable Gravitational Waves at the Einstein Telescope and the Cosmic Explorer

Jinzheng Li and Pran Nath

We study supercooled first-order phase transitions in a supersymmetric hidden sector with a spontaneously broken $U(1)_X$, focusing on the frequency range of the Einstein Telescope and Cosmic Explorer. Along the D-flat direction the tree-level quartic vanishes, so the barrier is generated radiatively by soft SUSY-breaking splittings. In the $\overline{\rm DR}$ scheme the gaugino mass $M_{\tilde\lambda}$ sets the barrier depth, while the soft scalar mass $m_0$ stabilizes the broken vacuum. For $M_{\tilde\lambda}/v_X\simeq0.05$–$0.23$, the predicted signal reaches $\Omega_{\rm GW}h^2\sim3\times10^{-10}$ near the percolation boundary. The observable amplitude depends sensitively on the portal coupling $\delta$ through the hidden-to-visible temperature ratio at percolation: for a cold initial hidden sector the signal rises from the ET floor at $\delta=10^{-6}$ to $\Omega_{\rm GW}h^2\simeq7\times10^{-11}$ as the sectors approach thermal contact at $\delta=10^{-4}$, while a hotter initial hidden sector gives a large signal already for weak portal coupling. We follow this evolution with an 11-variable Boltzmann system that separates the cold nucleating exterior from the reheated true-vacuum interior; reheating mainly enters through the energy budget and redshift factors. The same hidden sector can reproduce $\Omega_{\rm CDM}h^2=0.12$ through relativistic dark-quark freeze-out followed by entropy dilution from hidden-Higgs decay, with $m_q\simeq30$–$800\;$keV and $N_{\rm eff}\lesssim{\rm few}\times10^{-5}$.
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Fluid Dynamics

Effects of mean flow skew on turbulent shear layers. Part II. Experimental investigation

Dipendra Gupta, Vedant Kumar, Johan Larsson et al. (+1 more)

Planar turbulent mixing layers, formed by the interactions of two parallel streams with different velocities, have been studied far more than three dimensional (3D) turbulent mixing layers, in which the incoming streams are skewed, and not parallel. Yet many practical shear flows are 3D. Here, we develop and validate an experimental methodology to generate and characterize skewed turbulent mixing layers and to quantify how mean-flow skew modifies mixing layer dynamics. We introduce skew with a spanwise deflection of the mean flow using turning vanes mounted near the trailing edge of a splitter plate, and we use cross-wire anemometry to investigate the downstream evolution of the flow. Relative to the planar configuration, the skewed mixing layer exhibits systematic reductions in both mean and turbulent quantities, with deviations reaching approximately 40%. Despite these quantitative differences, the fundamental characteristics of the mixing layer remain largely unchanged. Mean-velocity profiles collapse under similarity scaling, shear-layer thicknesses retain approximately linear downstream growth, and Reynolds-stress profiles preserve their characteristic near-Gaussian form. Townsend's structure parameter, which quantifies the efficiency of turbulent momentum transport, remains approximately invariant between the planar and skewed configurations, in contrast to skewed turbulent boundary layers, wherein comparable mean flow skewing reduces the parameter by approximately 30%. These results indicate that mean flow skew modifies turbulent mixing layers quantitatively while exerting only a secondary influence on their underlying dynamics. This study establishes a controlled experimental framework and empirical benchmark for future investigations of three-dimensional free-shear turbulence.
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All authors Dipendra Gupta, Vedant Kumar, Johan Larsson, Gregory P. Bewley

High Energy Physics (Phenomenology)

Probing Axion Dark Matter via the Chiral Magnetic Effect in Zero-Bias Weyl Semimetals

Debajit Bose, Prataya Chandra, Sudhansu S. Mandal et al. (+1 more)

Sub-eV axion dark matter behaves as a coherent classical field that can induce macroscopic current in quantum materials. We explore the possibility of axion detection via the chiral magnetic effect in zero-bias Weyl semimetals under a static external magnetic field. We demonstrate that for a $1 \, {\rm cm^2}$ sample in a realistic $10 \, {\rm T}$ magnetic field, the signal remains in the observable femto-ampere range. Utilizing state-of-the-art SQUID-based current readout, the setup can probe axion-electron couplings below existing stellar cooling bounds across a broad range of axion masses.
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All authors Debajit Bose, Prataya Chandra, Sudhansu S. Mandal, Tirtha Sankar Ray

General Relativity and Quantum Cosmology

Trapped Surface as a Cosmic Censor

Hideo Furugori, Daisuke Yoshida and Kaho Yoshimura

We formulate a local geometric criterion for weak cosmic censorship in black hole overcharging and overspinning thought experiments. Under the null convergence and generic conditions, matter injection turns a horizon cross section into a closed trapped surface. Any final spacetime unable to accommodate this surface is ruled out. This trapped surface criterion excludes superextremal Reissner-Nordström, Reissner-Nordström-de Sitter, and Kerr-Newman final states, as well as Weyl-class naked singularities. Our criterion does not rely on asymptotic charges or on an extremal condition characterizing naked singularities.
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Materials Science

Cepstral Analysis to accelerate Green-Kubo thermal conductivity calculations of Metal-Organic Frameworks

Florian P. Lindner, Egbert Zojer and Sandro Wieser

Metal-organic frameworks (MOFs) are promising porous materials for applications such as gas storage and separation, where heat transport can critically affect device performance. However, reliable computational prediction of their thermal conductivities remains challenging. In particular, equilibrium molecular-dynamics-based Green-Kubo (GK) simulations, as the most widely used approach, are severely affected by statistical noise. Moreover, they rely on multiple ambiguous, user-defined parameters, which hinder transferability and automation. Here, we demonstrate for metal-organic frameworks that cepstral analysis in combination with GK simulations provides a robust route to massively mitigate these problems, while simultaneously reducing the required sampling times. This is shown for three prototypical frameworks, MOF-5, HKUST-1, and ZIF-8, employing machine-learned moment tensor potentials trained on DFT reference data. In contrast to conventional, direct GK analysis, which shows erratic convergence and strong sensitivity to ad hoc choices of parameters, the cepstral approach yields stable results across a wide range of correlation lengths and achieves convergence within about 1-2 ns of total sampling time. This establishes cepstral analysis base Green-Kubo simulations combined with machine-learned potentials as an efficient, reproducible and automation-ready framework for near ab initio accuracy prediction of thermal transport in MOFs and other complex low-thermal-conductivity materials.
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Soft Condensed Matter

Exploratory digital alchemy for colloidal crystal discovery

Shih-Kuang Lee, Sun-Ting Tsai and Sharon C. Glotzer

Digital Alchemy (DA), introduced by Van Anders et al., is a statistical mechanics-based generalized thermodynamic ensemble method that employs computer simulations to optimize colloidal particle design. This approach applies the principles of statistical mechanics to predict and tailor particle attributes that lead to desired self-assembled structures or material properties. However, as an inverse design method, its main limitation is that the target structure must be known a priori. Therefore, the optimal design from DA does not guarantee the targeted structure is the most or the only stable one. This highlights the importance of forward design with an exploratory scheme for optimizing novel colloid designs, which becomes more suitable in such cases. In this paper, we introduce Exploratory Digital Alchemy (EDA), an enhanced forward design scheme that begins by releasing the constraint of the target crystal from DA, followed by an exploration-oriented bias that has been extensively used in enhanced sampling methods such as metadynamics (MetaD). We demonstrate the utility of EDA through examples involving particles interacting via a two-dimensional Lennard-Jones Gauss potential (LJGP) and a three-dimensional oscillating pair potential (OPP). We applied EDA to study the free energy landscapes given different potential parameters of LJGP at different temperatures. With the exploratory scheme, we've also successfully identified a wide range of OPP potential parameters that stabilize metastable Frank-Kasper phases. Our approach fuses the standard DA framework with metadynamics, which could potentially be useful for studying alchemical reactions in a generalized ensemble.
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Soft Condensed Matter

Limits of constant-parameter constitutive models for hydrogels under inertial cavitation

Tianyi Chu, Joseph Beckett, Zhiren Zhu et al. (+2 more)

Mechanical characterization of soft materials at high strain rates is challenging due to their high compliance, nonlinear viscoelastic behavior, and potentially history-dependent responses. Inertial microcavitation rheometry (IMR) addresses this challenge by coupling laser-induced cavitation (LIC) experiments with numerical simulations of bubble dynamics models to infer constitutive models and material parameters. Both IMR and its variants infer parameters that depend on the chosen fitting window, which suggests that a constant-parameter constitutive model is insufficient to describe the full cavitation event. We use this window dependence to identify when the constant-parameter assumption fails, rather than to report a single effective parameter set. The constitutive parameters are estimated over moving, overlapping windows using a modified iterative ensemble Kalman smoother with multiple data assimilation (MIEnKS-MDA). Within the neo-Hookean Kelvin–Voigt (NHKV) constitutive model, we obtain time-resolved estimates of the constitutive response in polyacrylamide (PAAm) hydrogels with different crosslinker concentrations. The inferred shear modulus and viscosity generally decrease and then plateau during cavitation, while exhibiting relatively weak temperature sensitivity. For gelatin gels, by contrast, the inferred property evolution shows a pronounced temperature dependence, with distinct trends at low and high temperatures. Moreover, both the apparent shear modulus and viscosity exhibit significant variations during the first two bubble collapses. These results show that time-resolved parameter estimation within the prescribed NHKV constitutive structure can diagnose where the constant-parameter model assumption falls short during cavitation, thereby guiding the development of improved physics-based models of complex bubble–material interactions.
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All authors Tianyi Chu, Joseph Beckett, Zhiren Zhu, Jonathan B. Estrada, Spencer H. Bryngelson

Physics and Society · Cross-listed from cs.CY

The Tone of Awareness: Topic, Sentiment, and Toxicity Maps During Mental Health Month on TikTok

Henrique Ferraz de Arruda, Andreia Sofia Teixeira, Pranay Gundala Reddy et al. (+3 more)

Despite raising concerns about the mental health effects associated with the usage of TikTok, little is known about how related content is framed by creators and received by audiences. We collect the content of 28,341 TikTok videos and 80,130 comments from Mental Health Awareness Month (May) in 2023 and 2024 via the TikTok Research API, and study how the tone of awareness varies across topics and years. We characterize "tone" as the emotional and interpersonal framing of mental health discourse, operationalized through sentiment and toxicity measures. We extract topics from video text using BERTopic and log-odds keywords, then quantify topic-conditioned sentiment (XLM-T) and toxicity (Detoxify) separately for video transcriptions and comments. Sentiment captures the affective valence of content, while toxicity reflects the presence of harmful or abusive language. We find a stable set of recurring themes across years, spanning clinical conditions, emotional disclosure, self-care, and campaign-oriented content, with engagement highly skewed toward a small subset of topics. All sentiment and toxicity analyses are computed separately for video content and comments, allowing us to distinguish between content production and audience reception. Sentiment in videos is often negative for emotionally charged topics, while comments tend to shift toward more mixed or positive polarity, especially for suicide prevention. Toxicity is low in median overall, but exhibits longer-tailed outliers in comments than in videos that are more pronounced in comments and concentrated in specific topics (e.g., "Duet", "Suicide Prevention", and "Psychisch"). Overall, our results provide a topic-level decomposition of mental health discourse on TikTok during awareness-month campaigns.
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All authors Henrique Ferraz de Arruda, Andreia Sofia Teixeira, Pranay Gundala Reddy, Anindya Mondal, Kleber Andrade Oliveira, Filipi Nascimento Silva

Earth and Planetary Astrophysics

AESTRA II: Generative Spectral Modeling of the Sun as a Star for Precise Radial Velocities

Yan Liang, Joshua N. Winn, Peter Melchior et al. (+2 more)

The detection of Earth analogs with extreme-precision radial velocities (EPRVs) is limited by spectral variability from stellar activity, telluric absorption, and instrumental systematics. We apply AESTRA, a generative spectrum modeling framework, to NEID Sun-as-a-star observations. AESTRA empirically decomposes the spectra into stellar line-shape variability, micro-telluric absorption, and continuum variability without external atmospheric or stellar templates. After removing the learned telluric and continuum components, we train a low-dimensional representation of the spectrum to infer activity-driven apparent RVs jointly with candidate Doppler signals. We evaluate the method with 500 single-planet injection-recovery tests spanning periods of 2.5 to 400 days and semi-amplitudes of K = 0.1 to 0.7 m s^-1, calibrating the detection criterion to yield zero spurious detections. At this matched confidence level, AESTRA recovers 238 injected planets, including 13 with K < 0.3 m s^-1, whereas traditional CCF-based activity-indicator detrending recovers 9 planets and none below K = 0.5 m s^-1.
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All authors Yan Liang, Joshua N. Winn, Peter Melchior, Sicong Lu, Quang H. Tran

Materials Science

Tuning perpendicular magnetic anisotropy in ultra-low damping Li$_{0.5}$Al$_{x}$Fe$_{(2.5-x)}$O$_4$ thin films for efficient spin-orbit torque switching

Daisy O'Mahoney, Sauviz P. Alaei, Anna Janni et al. (+5 more)

Ultra-thin magnetic insulator films that simultaneously exhibit ultra-low magnon damping, perpendicular magnetic anisotropy (PMA), and low spin-orbit torque (SOT) switching current densities are highly desirable, albeit challenging, for next-generation spintronic technologies that exploit spin waves to transport information without dissipative charge currents. Here, we demonstrate this combination of properties in ferrimagnetic spinel Li$_{0.5}$Al$_{x}$Fe$_{(2.5-x)}$O$_4$ (LAFO) thin films. Through this model system, we find that PMA can be tuned by epitaxial strain in the form of chemical composition and substrate choice and that low SOT switching current densities correlate with small but finite PMA. Ultra-low damping is stabilized primarily by having only Fe$^{3+}$ as magnetically active cations with secondary effects due to increased disorder from Al substitution distribution. SOT efficiency is governed by interface quality and independent of chemical composition. By varying the Al concentration, we systematically tune the saturation magnetization and magnetic anisotropy while maintaining ultra-low Gilbert damping parameters as low as $2\times10^{-4}$ and composition-independent damping-like SOT efficiencies. We identify an optimal composition LAFO x=0.7 (Li$_{0.5}$Al$_{0.7}$Fe$_{1.8}$O$_4$), which combines ultra-low damping, stable PMA with small anisotropy fields, and low critical current densities for SOT switching, establishing it as a promising material platform for energy-efficient spin-wave and spintronic devices.
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All authors Daisy O'Mahoney, Sauviz P. Alaei, Anna Janni, Muzhda Mehrzad, Christoph Klewe, Alpha T. N'Diaye, Zbigniew Galazka, Yuri Suzuki