Chemical Physics
X-ray Driven Trihydrogen Formation on Silica Nanosurfaces
Samuel Sahel-Schackis, Adam Summers, Ritika Dagar et al. (+29 more)
The trihydrogen cation ($\mathrm{H_3^+}$) initiates the ion-molecule reactions that build molecular complexity in interstellar space. Whether its canonical formation reaction, $\mathrm{H_2^+ + H_2 \rightarrow H_3^+ + H}$, proceeds on inorganic surfaces under radiation-driven ionization has remained untested. Here we drive $\mathrm{H_3^+}$ formation on hydrated silica nanoparticles using intense 1.88 keV X-ray pulses, combining ion velocity map imaging, electron time-of-flight spectroscopy, and single-particle coherent diffractive imaging to resolve this chemistry on individual particles. The self-induced surface electric field on the V/nm scale drives interfacial charge transfer and water fragmentation. This field is the dominant parameter governing the relative yields of $\mathrm{H^+}$, $\mathrm{H_2^+}$, and $\mathrm{H_3^+}$ across particle size, composition, and aggregation. Density functional theory and nonadiabatic
quantum molecular dynamics simulations trace this field-driven charge transfer, directly analogous to band bending at
semiconductor photoelectrodes. These results establish surface-field-driven charge transfer as a unifying mechanism between radiation dominated astrophysical environments and field-driven surface catalysis.
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All authors Samuel Sahel-Schackis, Adam Summers, Ritika Dagar, Alexandra Feinberg, Martin Grassl, Simon Dold, Rebecca Boll, Yevheniy Ovcharenko, Chris Aikens, Cesar Costa Vera, Alberto De Fanis, Avijit Duley, Felix Gerke, Daniel Jost, Regina Leiner, Michael Meyer, Ilana J. P. Molesky, Razib Obaid, Jeffrey Powell, Nils Rennhack, Björn Senfftleben, Hendrik Tackenberg, Paul Tuemmler, Sergey Usenko, Christian Peltz, Thomas Fennel, Markus Gallei, Eckart Rühl, Artem Rudenko, Daniel Rolles, Thomas Linker, Matthias F. Kling
Computational Physics · Cross-listed from cs.CE
A hybrid s-version isogeometric strategy for dynamic crack propagation in 2D and 3D problems
Tianyu He, Kosei Kurosaki, Naoki Morita et al. (+2 more)
A hybrid s-version of isogeometric analysis (hS-IGA) strategy is proposed for accurate and efficient evaluation of near-crack fracture quantities in dynamic crack propagation analysis. The strategy retains the global-local superposition framework of the conventional s-method, while introducing B-spline basis functions only into the global discretisation and preserving a Lagrange-based local mesh in the crack domain. This hybrid formulation is motivated by the continuity-related bottleneck in the global-local coupling integration of the conventional Lagrange-based s-method, and by the need to retain a Lagrange-based local mesh for crack representation and post-processing of the dynamic stress intensity factor (DSIF) and local stress. The resulting formulation removes discontinuities in the coupling integrands caused by the global approximation and enables accurate coupling integration by standard Gauss quadrature without recursive subdivision. The proposed strategy is verified using two-dimensional stationary and dynamic straight-crack problems against the standard finite element method and the conventional s-method, and is further assessed using three-dimensional stationary and dynamically propagating circular-crack problems against the conventional s-method. Results show that the proposed hS-IGA strategy accurately evaluates the DSIF and local stress while retaining the global-local modelling advantages of the s-method. It also substantially reduces the number of integration points required for coupling integration, by approximately 81% in the two-dimensional dynamic
benchmark and 95.6% in the three-dimensional dynamic
benchmark relative to the conventional s-method. These results demonstrate that the proposed hS-IGA framework provides an accurate and efficient global-local strategy for dynamic crack propagation analyses requiring reliable evaluation of near-crack fracture quantities.
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All authors Tianyu He, Kosei Kurosaki, Naoki Morita, Naoto Mitsume, Kazuki Shibanuma
High Energy Astrophysical Phenomena
Influence of effective mass of the relativistic mean field theory on core collapse supernovae and compact objects
Kohsuke Sumiyoshi, Hajime Togashi, Shun Furusawa et al. (+4 more)
We study the influence of the effective mass in the relativistic mean field (RMF) theory on the properties of the central core of collapse-driven
supernovae and the formation of compact objects. Influence of the effective mass has been so far studied within the non-relativistic frameworks. In order to clarify the role of the effective mass in the relativistic frameworks, which is different from non-relativistic ones, we adopt the set of equation of state (EOS) tables using the parameterizations TM1e and TM1m, which have different effective masses but with the same saturation properties, in the RMF theory. We show that choices of the effective mass in
supernova matter affect both the stiffness of the EOS through pressure and the thermodynamical behavior through temperature under the RMF frameworks. We explore differences in matter
evolution with
neutrino emissions by performing a set of numerical simulations of the gravitational collapse and bounce of massive
stars and the cooling of the proto-
neutron stars. The EOS with large effective mass leads to compact proto-
neutron stars and early collapse to black holes with high densities and temperatures due to the softness. It leads to high energy
neutrinos in long emission from the proto-
neutron star cooling and in short burst from the black hole formation.
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All authors Kohsuke Sumiyoshi, Hajime Togashi, Shun Furusawa, Shuying Li, Hong Shen, Ken'ichiro Nakazato, Hideyuki Suzuki
Solar and Stellar Astrophysics
Distribution of magnetic helicity and energy with height in solar atmosphere
Hongyan Li, Shangbin Yang, Haiqing Xu et al. (+3 more)
Magnetic helicity and
magnetic energy are key to understanding the
solar dynamo and eruptions, and their three-dimensional distributions are of great significance. However, how these quantities vary with height remains poorly understood. Moreover, because the three-dimensional distribution depends on
magnetic field extrapolation, determining the optimal extrapolation height from physical rather than empirical criteria remains an open problem. To address this issue, this work investigates the vertical distributions of
magnetic helicity and
magnetic energy in the
solar corona within active regions. We analyze 150 active regions observed by the
Solar Magnetic Field
Telescope (SMFT) from 1988 to 2019, grouped by absolute
magnetic flux, perform nonlinear force-free field (NLFFF) extrapolations, and compute the relative
magnetic helicity with a finite volume method. It is found that an extrapolation height of at least 81 Mm retains 97% of the total
magnetic helicity and energy while reducing computational costs by approximately 38% under the adopted configuration. This work provides important parameter constraints for the long-term statistical study of
magnetic helicity in
solar active regions.
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All authors Hongyan Li, Shangbin Yang, Haiqing Xu, Quan Wang, Anda Xiong, PeiXin Luo
Strongly Correlated Electrons
Local Spin Excitations Mediate Quasiparticle Breakdown in the Orbital-Selective Mott Phase
Yuekun Niu, Yu Ni, Jia-Ming Wang et al. (+3 more)
The orbital-selective Mott phase (OSMP) is commonly described as a coexistence of localized and itinerant electrons within effectively decoupled orbitals, but emerging evidence for quasiparticle breakdown points to physics beyond this picture, whose microscopic origin remains unknown. Using dynamical mean-field theory for the two-band Hubbard model, we show that the
spin-flip and Ising-type components of Hund's coupling generate local
spin excitations (LSEs). These LSEs couple electrons between different orbitals, renormalize quasiparticle lifetimes and binding energies, and thereby destroy well-defined quasiparticles in the OSMP. Removing these two components of Hund's coupling restores coherent quasiparticle behavior and fully decouples the charge dynamics of the two bands. Our results therefore identify electronic coupling to LSEs as the fundamental mechanism driving quasiparticle breakdown within the OSMP.
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All authors Yuekun Niu, Yu Ni, Jia-Ming Wang, Zhong-Yi Lu, Yun Song, Shiping Feng
Plasma Physics
Millisecond-Scale Neural Operator Surrogates for Double-Null Free-Boundary Grad-Shafranov Equilibria
Plamen G. Krastev
The Grad-Shafranov (GS) equation governs ideal magnetohydrodynamic
equilibrium in tokamak
plasmas. Free-boundary GS solvers are central to diverted-
equilibrium modeling, but nonlinear Picard iteration introduces computational cost and sample-dependent latency that can become prohibitive in optimization, modeling, and control-oriented loops. Here we train a geometrically conditioned
Fourier Neural Operator (FNO) to learn a constrained forward map from spatial coordinates, scalar operating parameters $(P_{\mathrm{axis}}, I_p, f_{\mathrm{vac}})$, and prescribed X-point locations to the poloidal-flux field $\psi(R,Z)$. The model is trained on a controlled family of constrained double-null free-boundary
equilibria generated with FreeGS for a single fixed machine geometry and prescribed
topology. The best model achieves a mean relative $L^2$ error of $0.05\%$, with test error following an empirical $N^{-0.68}$ power law over $N_{\mathrm{train}}\in\{500,1000,2000,5000\}$. It recovers both X-points to within $0.2$ cm and localizes the O-point to $0.03$ cm. As a physics-consistency diagnostic, the predicted fields satisfy an external finite-difference GS residual evaluation at the same level as the ground-truth fields, with mean normalized residual $2.29$, indistinguishable from the $2.29\pm0.06$ FreeGS baseline using the same diagnostic. The trained FNO evaluates one
equilibrium in $2.77$ ms on GPU and $25.6$ ms on CPU, corresponding to speedups of ${\sim}640\times$ and ${\sim}69\times$ relative to FreeGS as configured here, with near-deterministic latency (p95/median $=1.01$). These results show that neural-operator surrogates can provide accurate, geometrically precise, millisecond-scale
equilibrium evaluations for
magnetic-confinement fusion workflows within a prescribed
topology and machine geometry.
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Instrumentation and Methods for Astrophysics
MARS: A Lightweight Morphology-Aware RFI Segmentation Network for Mask-Guided Mitigation in Radio Astronomy
Zhaocheng Gong, Jack White, Jayanta Roy et al. (+1 more)
Next-generation
radio telescopes generate filterbank data at rates that make storing all observations for later offline mitigation impractical. Mitigation must therefore operate in real or near-real time within the search pipeline while preserving dispersed astrophysical signals. CPU tools fit GPU-centred search pipelines poorly, while neural alternatives can be computationally heavy. We present MARS, a GPU-based RFI mitigation pipeline centred on a lightweight Morphology-Aware RFI
Segmentation Network. The model is a reduced-width, full-resolution U-Net with a bottleneck containing local, horizontal, and vertical filters to capture compact and elongated RFI structures in the frequency-time plane. Normalisation, patch construction, mask reconstruction, replacement, baseline removal, and output rescaling are also implemented on GPU. Training includes an astronomical-signal preservation loss that discourages false flagging of dispersed pulses. In controlled patch-level tests, MARS achieves an RFI-mask F1 score of $0.978$ and a precision of $0.995$. It retains $97.6\%$ of the injected dispersed-signal fluence in clean patches and $96.4\%$ of the non-overlapping signal fluence in patches containing mixed injected RFI. Ablation experiments show that the astronomical-signal preservation loss particularly improves the protection of compact, low-DM, high-S/N pulses. At filterbank level, period-matched PRESTO candidates recovered after MARS mitigation have median significance ratios of $0.90$–$0.99$ relative to filtool. Both methods also recover the known
pulsars in two real GMRT observations. On an NVIDIA GH200 GPU, MARS achieves a compute-only speedup of $6.2\times$–$7.0\times$ over the fastest tested multi-threaded filtool configurations on an AMD EPYC 9825 CPU.
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All authors Zhaocheng Gong, Jack White, Jayanta Roy, Wesley Armour
High Energy Physics (Phenomenology)
Coherent and Stochastic Axion Dark Matter from Thermal Relaxation
Shahid Hussain Gurmani, Arzu Cilli, Phongpichit Channuie et al. (+3 more)
An
axion driven toward a thermal minimum need not remain a coherent condensate. We derive the coupled attenuation of the field mean and production of
stochastic momentum modes in an expanding
plasma. A single momentum dependent optical depth partitions every mode between coherent power and Bose occupation, placing standard misalignment, partial relaxation, and
stochastic production in one dynamical relation. Finite spatial and temporal response suppresses high momentum production, so the
stochastic relic has lower mean momentum and a shorter free streaming length than an
equilibrium population at fixed mass and bath temperature. A weakly coupled realization produces the dark matter abundance, reduces inherited coherent isocurvature, and confines production correlations to scales removed by collisionless propagation. Thermal relaxation therefore determines the composition, momentum distribution, and transported structure of
axion dark matter.
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All authors Shahid Hussain Gurmani, Arzu Cilli, Phongpichit Channuie, Ahmadjon Abdujabbarov, Farruh Atamurotov, Ertan Güdekli
Quantum Physics
Quantum information loss
James Fullwood, Wu-zhong Guo and Boyu Yang
We introduce a measure of information loss for any
quantum process that may be modeled by a prepare-evolve-measure scenario: Alice prepares an ensemble of states that gets sent via a
quantum channel to Bob, who then measures the output. As a
quantum channel models open system dynamics, our measure of information loss quantifies Bob's inability to retrodict with certainty which state Alice sent through the channel. By minimizing this measure over all possible pure state ensemble decompositions of a fixed state $\rho$, and over all POVMs on the output of a channel $\mathcal{E}$, we arrive at an intrinsic notion of information loss for any state-channel pair $(\rho,\mathcal{E})$. We show that the vanishing of information loss with respect to all states supported on a fixed codespace $\mathcal{H}_{\text{code}}$ is equivalent to a condition we term universal pristineness, which ensures that orthogonal pure states in $\mathcal{H}_{\text{code}}$ get sent via the channel $\mathcal{E}$ to possibly mixed states whose supports are orthogonal. Moreover, we prove universal pristineness is equivalent to the Knill-Laflamme conditions in
quantum error correction, which are necessary and sufficient for the existence of a perfect recovery channel for all states supported on $\mathcal{H}_{\text{code}}$. As an application, we apply our framework to the Hayden-Preskill model of black hole evaporation, demonstrating that the evaporation channel becomes asymptotically universally pristine, thereby providing a purely channel-theoretic formulation of Page-time information
retrieval.
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High Energy Astrophysical Phenomena
No evidence for a supermassive black hole binary in GSN 069
Yuhe Zeng, Zhen Pan, Bin Liu et al. (+1 more)
Quasi-periodic eruptions (QPEs) are recurrent soft X-ray
flares from
galactic nuclei and provide a new time-domain probe of
stellar-mass objects (SMOs) orbiting supermassive black holes (SMBHs). In an extreme-mass-ratio inspiral (EMRI) system interacting with an
accretion disk, QPEs are produced when the SMO repeatedly crosses an
accretion disk, so that the eruption times trace the orbital motion of the EMRI. We investigate whether such timing information can be used to probe a more distant SMBH companion. We develop two complementary diagnostics: (1) the motion of the EMRI host SMBH around the SMBH-binary (SMBHB) center of mass induces a light-travel-time modulation in the observed QPE arrival times, specifically an in-phase modulation in arrival times of even and odd eruptions; (2) if the QPE source contains a surviving
stellar orbiter, the external SMBH must not drive the SMO into
tidal disruption through eccentricity excitation by the von Zeipel–Lidov–Kozai (ZLK) mechanism. Using GSN 069 as an example, we find no in-phase modulation in the QPE timing (i.e., no evidence for a SMBHB) and constrain the excluded parameter space of the companion SMBH. These results demonstrate that QPE timing and
stellar survival offer complementary routes for constraining otherwise hidden SMBH companions in nearby
galactic nuclei.
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All authors Yuhe Zeng, Zhen Pan, Bin Liu, Cong Zhou
Strongly Correlated Electrons
Strongly Enhanced Charge-Density Waves and Correlated Insulating State in Atomically Thin 1$T$-TaS$_2$
Gan Liu, Yulu Liu, Qiling Luo et al. (+7 more)
We investigate thickness-dependent charge-density-wave (CDW) transitions in 1$T$-TaS$_2$ using temperature-dependent Raman spectroscopy and electrical transport. Raman measurements show that the incommensurate, nearly commensurate, and commensurate CDW phases persist down to the monolayer limit. As the thickness is reduced, the transition temperatures increase, accompanied by an orders-of-magnitude rise in sheet resistance and a sharp reduction in the carrier localization length. The first-order hysteretic CCDW-NCCDW transition is uniquely absent in the monolayer. Calculations suggest that the enhanced CDW in thin layers originates from strengthened Coulomb interactions due to reduced out-of-plane screening, particularly in the nonlocal component. These findings highlight the cooperative roles of electron correlation, electron-
phonon interaction, and interlayer coupling in shaping the ground state and transition dynamics of atomically thin 1$T$-TaS$_2$, opening pathways for engineering correlated phases in two-dimensional CDW systems.
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All authors Gan Liu, Yulu Liu, Qiling Luo, Zhentao Huang, Kenji Watanabe, Takashi Taniguchi, Meiyu Wang, Jinsheng Wen, Yi Lu, Xiaoxiang Xi
High Energy Astrophysical Phenomena
A Roadmap for Transient Hunters: Mapping Stellar Mass and Star Formation Rate Anisotropies in the Local Universe
Ye-Hao Cheng, Yuan-Pei Yang and Ye Li
Over the past few decades, an increasing number of transients in nearby
galaxies have been discovered through various survey projects. Unlike astrophysical phenomena at cosmological distances, transients in the local universe exhibit a pronounced anisotropy in their sky distribution. Consequently, adopting an appropriate survey strategy is essential to improve the efficiency of transient searches in the local universe. In this work, we utilized a large
galaxy catalog to map the sky distributions of
stellar mass and
star formation rate (SFR) across different luminosity distance thresholds and angular resolutions of the grid on the celestial sphere. These maps can further serve to characterize the anisotropic spatial distribution of nearby extragalactic transients. For different angular resolutions of the celestial sphere, we find that the sky distributions of
stellar mass of
galaxies are similar to those of the SFR in the main anisotropic structures. As the luminosity distance threshold increases, the anisotropic structures of the sky distributions become more isotropic. We calculate the angular power spectra and fluctuations of the sky distribution of
stellar mass and SFR at a given angular resolution and find that the angular power spectra and fluctuations decrease rapidly as the luminosity distance threshold increases. Finally, by qualitatively comparing the sky distribution of core-collapse
supernovae with our SFR sky distribution, we find that the two exhibit consistent patterns in several prominent structures. The mapped sky distributions of
stellar mass and SFR can serve as valuable references for future surveys in searching for extragalactic transients.
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Cosmology and Nongalactic Astrophysics
photo-3x2-pt: Cosmology from cosmic shear and galaxy clustering with a single photometric galaxy catalog
Takashi Hamana
We perform a joint cosmological analysis using angular power spectra of
galaxy clustering,
galaxy-shear cross correlation, and
cosmic shear (hereafter referred to as photo-3x2-pt) measured from the Hyper Suprime-Cam year-3 (HSC-Y3) weak
lensing shape catalog. We employ the pseudo-$C_\ell$ method to measure these power spectra and use the template deprojection method to mitigate systematics in the
galaxy density maps. We perform a standard
Bayesian likelihood analysis for cosmological inference based on the measured photo-3x2-pt, including contributions from intrinsic
alignments of
galaxies,
galaxy clustering bias,
lensing magnification effect, baryonic feedback effect, and source
redshift distribution errors. For a flat cold dark matter model, we find a 68% credible interval of $0.76 \le S_8 \le 0.81$. This result is consistent with the HSC-Y3
cosmic shear analyses (Dalal et al. 2023, Li et al. 2023) but is $\sim 25$% tighter. We also find that the measured B-mode power spectra are consistent with zero. We also perform a performance test using mock catalogs that mimic the HSC-Y3 data to validate our photo-3x2-pt analysis. Through
Bayesian parameter inference of mock data, we verify that unbiased estimates can be obtained for the key cosmological and nuisance parameters, including $S_8$, intrinsic
alignment model parameters,
galaxy clustering bias, and shift parameters of the source
redshift distributions.
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Materials Science
Emergent Surface Altermagnetism
Yuzhong Hu, Pan Zhou, Baoru Pan et al. (+3 more)
Research on altermagnetism has thus far primarily focused on
spin-polarized bulk electronic states in
magnetic materials. In this work, we advance the field by introducing the concept of surface altermagnetism (SAM), wherein altermagnetic
spin polarization emerges at the surfaces of collinear antiferromagnets (AFMs) or altermagnets (AMs). To lay the theoretical groundwork for this phenomenon, we construct a thorough
symmetry-based framework that systematically connects bulk
spin groups to surface
spin groups for both types of systems. Through
symmetry analysis, we identify all
symmetry-breaking surfaces capable of supporting SAM, identifying 35 for $PT$-symmetric AFMs and 61 distinct cases for bulk AMs. Moreover, we show that 203 collinear
spin space groups—including 100 without and 103 with the $[C_2 \Vert P]$ operation—permit the appearance of SAM on the surface of $tT$-symmetric AFMs via the breaking of fractional translational
symmetries. The proposed framework is verified using tight-binding models and first-principles calculations, with practical material implementations shown in representative compounds like NaMnP, LiMnAs, and CrSb. Our results establish SAM as a robust,
symmetry-protected
magnetic state, extending altermagnetic phenomena to material surfaces and paving the way for advanced, field-free
spin manipulation in next-generation spintronic technologies.
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All authors Yuzhong Hu, Pan Zhou, Baoru Pan, Songmin Liu, Binchang Zhou, Lizhong Sun
Materials Science
Intra-unit-cell resolved intertwining of multi-$Q$ charge and spin textures in an itinerant skyrmion magnet
Christopher J. Butler, Katsuki Nihongi, Haruto Yoshimochi et al. (+4 more)
The mechanisms stabilizing non-collinear magnetism in centrosymmetric
crystals remain unclear, but likely involve
spin-
spin interactions mediated by itinerant electrons, such as the RKKY interaction. Finite-$Q$
magnetic order may then be accompanied by electronic modulations that are observable using a scanning tunneling microscope. In five successive
magnetic phases of GdRu$_{2}$Ge$_{2}$, including two nano-scale skyrmion
crystal phases, we show that multi-$Q$ magnetism among Gd 4$f$
spins entails a corresponding multi-$Q$ texture among the Ru 4$d$ orbitals that contribute itinerant electron bands. With atomically-resolved images of each electronic texture's motif, and a simple numerical modeling scheme drawing on the underlying
spin structures, we infer their key relationship: The
alignment between nearest-neighbor Gd
spins tightly correlates with the local density-of-states of the Ru 4$d$ orbitals on the two bond-centered sublattices of the Gd square net. These analyses offer a microscopic view of the atomic-scale intertwining of charge and
spin degrees-of-freedom in non-collinear itinerant magnets.
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All authors Christopher J. Butler, Katsuki Nihongi, Haruto Yoshimochi, Nguyen Duy Khanh, Rina Takagi, Tetsuo Hanaguri, Shinichiro Seki
Quantum Physics
A Unified Framework for Sample Complexity of Structured Quantum State Tomography under Noisy Observations
Zhen Qin
Quantum state
tomography (QST) has attracted considerable
attention due to its fundamental role in
quantum information processing. In this paper, we develop a unified theoretical framework for analyzing the sample complexity of structured QST under noisy observations arising from state preparation noise, measurement noise, and finite-shot statistical noise. The proposed framework applies to a broad family of structured
quantum-state classes, including general mixed states, sparse states, low-rank states,
matrix product states (MPSs),
matrix product operators (MPOs), projected entangled-pair states (PEPSs), and projected entangled-pair operators (PEPOs), while further introducing physically consistent structured models—including low-rank and sparse states, low-rank MPOs (LR-MPOs), and low-rank PEPOs (LR-PEPOs)—that simultaneously exploit low-dimensional structures and preserve the physical constraint. Within this framework, we derive unified non-asymptotic sample complexity guarantees for two constrained least-squares
estimators under noisy observations: a noise-aware
estimator that incorporates the calibrated noise model and a noise-unaware
estimator based on the ideal Born measurement model. For the noise-aware
estimator, we derive unified trace-norm recovery guarantees that explicitly characterize the dependence of the sample complexity on three fundamental quantities: the complexity of the underlying structured state class, the complexity of the measurement ensemble, and the state preparation and measurement noise levels. For the noise-unaware
estimator, we establish a unified non-asymptotic recovery guarantee consisting of a statistical error term and an additional deterministic bias term arising from the mismatch between the assumed reconstruction model and the noisy observation process.
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Mathematical Physics
On the synthesis of complete two-dimensional second-gradient continua: Tri-pantographic fabrics
Casey Rodriguez, Emilio Barchiesi, Simon R. Eugster et al. (+2 more)
We introduce a notion of completeness for two-dimensional second-gradient elastic continua and propose a microstructural route toward its synthesis. A continuum is said to be complete if the Hessian of the stored energy with respect to the second-gradient variable is locally positive definite, so that every nonzero admissible increment of the placement second gradient is quadratically controlled in the highest-order part of the energy about each configuration. Starting from the Principle of Virtual Work, we derive the constitutive relations,
equilibrium equations, and admissible boundary interactions for a broad class of fibrous second-gradient continua whose stored energies depend on fiber stretch, stretch gradients, and
curvature. The theory is then applied to several continua motivated by pantographic microstructures. Classical pantographic sheets are shown to be incomplete, while bi-pantographic fabrics enlarge the class of components of the second gradient detected by the energy but remain incomplete. Finally, we formulate a tri-pantographic continuum associated with a proposed three-family architecture and prove that it is complete. The examples illustrate how microstructural architecture influences both the completeness properties of an effective continuum and the pointwise form of its higher-order boundary interactions.
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All authors Casey Rodriguez, Emilio Barchiesi, Simon R. Eugster, Ivan Giorgio, Francesco dell'Isola
Chaotic Dynamics
Equation-Free Period-Aware Forecast-Error Contraction for Estimating Negative Largest Lyapunov Exponents from Short Trajectory Ensembles
Andrei Velichko, N'Gbo N'Gbo and Viet-Thanh Pham
Estimating positive largest Lyapunov exponents from data is comparatively natural because neighboring trajectories separate, whereas stable dynamics require resolving contraction before measurement noise or finite precision erases the signal. We introduce a period-aware forecast-error contraction procedure for estimating a dominant negative Lyapunov exponent from ensembles of short scalar trajectories without using governing equations or an analytical Jacobian. A k-nearest-neighbor predictor is trained on trajectory histories, the
geometric-mean absolute forecast error is evaluated at phase-consistent horizons, and the exponent is obtained from the slope of the logarithmic error profile. Unlike data-driven approaches that reconstruct local
evolution matrices or differentiate a learned surrogate, the proposed method extracts the contraction rate directly from out-of-sample forecast errors. Two adaptations are essential: the forecast step is synchronized with the detected orbit period, and candidate slopes are accepted only when they form a stable consensus across several transient lengths. On the logistic map, the method recovers 92 of 112 negative-exponent parameter values with a mean absolute error of 0.0253 and $R^2=0.886$. On a two-dimensional map without fixed points, independent scalar pipelines based on the three observables $x_n$, $y_n$, and $z_n$ give mean absolute errors of 0.00879–0.01145 and $R^2=0.983$–$0.986$. Because the estimation stage uses only observed trajectories, the framework provides a basis for repeated-relaxation experiments in which short sensor responses are available but the governing equations and analytical Jacobian are unknown. Experimental validation remains a subject of future work.
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Quantum Physics
X-Z Round Scheduling for the Surface Code with Defects under Biased Noise
Lakshika Rathi, Pau Escofet, Joshua Viszlai et al. (+1 more)
Fault-tolerant
Quantum Computing (FTQC) relies on
Quantum Error Correction (QEC) codes that encode logical
qubits across many physical
qubits to detect and correct errors. The surface code is among the most widely studied codes due to its high error threshold, the existence of efficient decoders, and hardware-friendly properties: a planar, two-dimensional layout with nearest-neighbor connectivity. In practice, however, the fabrication of solid-state
quantum processors introduces hardware defects, resulting in defective
qubits and couplers that must be discarded. Adapting the surface code to these defects often requires measuring the $X$- and $Z$-type checks in separate rounds rather than simultaneously. In this work, we investigate the optimal $X$-to-$Z$ checks round-scheduling ratio under biased noise systems. Our results characterize how key architectural parameters, such as noise bias, code distance, and defect rate, impact the logical error rate. We provide insights into how to determine the optimal scheduling ratio directly from device calibration data, enabling manufacturers to maximize performance without extensive simulations. Our approach reduces the logical error rate by up to $4.25\times$ at a $1\%$ defect rate and up to $8.46\times$ at a $2\%$ defect rate for a distance-$13$ surface code under moderately biased noise. Furthermore, we demonstrate that the benefits of round-scheduling extend beyond the defective-hardware setting. In biased-noise architectures subject to CNOT crosstalk, separating $X$ and $Z$ measurement rounds yields up to $4.5\times$ reduction in logical error rate.
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All authors Lakshika Rathi, Pau Escofet, Joshua Viszlai, Margaret Martonosi
Solar and Stellar Astrophysics
Hot molecular cores in the W49A molecular cloud complex
Ryosuke Miyawaki, Masahiko Hayashi and Tetsuo Hasegawa
We present a comprehensive
dataset of hot molecular cores (HMCs) in the W49A molecular cloud complex based on high-resolution ALMA observations, including the 1.3~mm continuum, 12 molecular lines, and the H30alpha recombination line. In total, 18 HMCs are identified in the CH$_{3}$CN ($J_K=12_3-11_3$) map, together with 20 continuum sources in the 1.3~mm map. Ten HMCs have peaks coincident within 0\farcs1 of the 1.3~mm continuum peaks, indicating that thermal
dust emission dominates the 1.3~mm emission for these sources. Correlation analyses of the line luminosities suggest a common structural picture for HMCs, in which five distinct regions with different physical and chemical properties coexist: hot and dense gas (CH$_3$CN, HC$_3$N, HNCO, OCS, H$_2$CO),
outflow gas (SiO, SO), envelope gas (SO$_2$, CH$_3$OH), extended gas ($^{13}$CS, DCN, C$^{18}$O), and ionized gas (H30alpha). We find an empirical relation $X(\mathrm{CH_3CN})=2.5\times10^{-7}\exp[-490/T_\mathrm{rot}]$ between the fractional abundance and rotation temperature of CH$_{3}$CN, suggesting that $T\gtrsim200$–300~K is required to achieve high abundances of $\sim10^{-7}$. We find that HMCs without embedded H/UCHII regions are more numerous than, or at least comparable in number to, HMCs with such regions, suggesting that the former may have longer lifetimes ($\sim$10$^{5}$~yr) than the latter ($\sim$10$^{4}$~yr). We discuss the implications of these results for the core
accretion and competitive
accretion models.
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Soft Condensed Matter
A floor and a ceiling for the advancing contact angle
Yong Sung Park
Reported maxima of the advancing contact angle scatter from $87^\circ$ to $147^\circ$ in a single systematic study, and
liquids on surfaces with static angles as low as $5^\circ$ reach dynamic maxima near $90^\circ$. We show that both observations follow from the hinged motion of the free surface near a moving contact line. The local Stokes solution for a wedge rotating about its contact line has two singular angles of opposite character: at $90^\circ$ the hinged motion generates no wall shear and the rotation is free, and at $\theta_h = 128.73^\circ$, where $\tan 2\alpha = 2\alpha$, a resonance with the $r^2$ eigensolution arrests the rotation through an $r^2 \ln r$ term. Between the two angles lies a band that a transient advancing angle cannot leave while the interface near the contact line remains a quasi-steady wedge. A compilation of 68
liquid-solid systems from nine sources and five configurations confirms the band and its two exits: systems not limited by the apparatus, with $\theta_s \le 40^\circ$, reach $87^\circ$ to $119^\circ$ regardless of chemistry, and every exceedance of $\theta_h$ occurs either where chemistry places the static angle above the band or where the flow leaves the quasi-steady regime. The record of a waterline on a vertical wall exhibits the band within a single unsteady experiment, together with a distinct quieting of the local contact angle at the crossing of $90^\circ$.
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Atomic Physics
Large anomalous shifts of potassium-39 Feshbach resonances
Ali Zaheer, Mohammed Bouras, Krzysztof Giergiel et al. (+3 more)
We report the observation of large anomalous shifts, up to +7.5 G, of the positions of the 33.6 G and 39.9 G Feshbach resonances in potassium-39 atoms confined in a 1063.9 nm optical dipole trap (ODT) at temperatures up to around 35 {\mu}K and trap depths up to about 136 {\mu}K. When the atom cloud is cooled to lower temperatures, by reducing the trap depth of the ODT, the shifts decrease proportionally with trap depth and approach zero at zero depth. We show that the large observed shifts originate from a large differential ac Stark shift between the incoming pair of potassium-39 atoms and the weakly bound Feshbach molecule, which in turn originates from an unexpectedly large dynamic polarizability of the Feshbach molecule. The polarizabilities of the Feshbach molecules extracted from the measured shifts of the 33.6 G and 39.9 G resonances are about four to seven times the sum of the polarizabilities of the two incoming potassium-39 atoms, that is, about four to seven times larger than the usual polarizability of weakly bound Feshbach molecules. The large polarizabilities of the Feshbach molecules are attributed to a near-coincidence between the frequency of the 1063.9 nm ODT
laser and the frequency of a molecular transition from the last vibrational level of the lowest triplet a3{\Sigma}+u potential to a vibrational level of the excited b3{\Sigma}+g potential. Other potassium-39 Feshbach resonances we have studied exhibit a zero or very small shift, corresponding to molecular polarizabilities close to the sum of the polarizabilities of the two incoming potassium-39 atoms.
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All authors Ali Zaheer, Mohammed Bouras, Krzysztof Giergiel, Rudolf Grimm, Andrei Sidorov, Peter Hannaford
High Energy Physics (Phenomenology)
Spinor tunnelling amplitudes from all-order Feynman diagram summation
Max Fleming and Cedric Simenel
This work presents a non-perturbative
quantum field theoretic computation of spinor tunnelling through a potential barrier. Within position space potential formalism, we identify coupled recursion relations forming a self-consistent integral equation. Our method, enabling both analytical and numerical approaches, transforms into a formalism admitting both numerical framework for arbitrary potentials and analytical exact results for select barriers. For the rectangular barrier, the QFT-derived amplitudes reproduce the relativistic
quantum mechanical (RQM) results, thus establishing a foundation for future calculation of beyond-RQM field-theoretic corrections.
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Earth and Planetary Astrophysics
Beyond Point Masses. VI. Spin-Orbit Evolution of the Centaur Binary Typhon-Echidna
Benjamin Proudfoot, Will Grundy and Darin Ragozzine
Only three binaries have been identified among the Centaur population. Because their perihelia are significantly closer than those of other trans-Neptunian binaries (TNBs), these systems allow a detailed look at tight binaries in the broader TNO population and provide critical insight into the disruption of binaries as they enter the Centaur population. Using recent and archival Hubble Space
Telescope (HST) observations, along with Keck data, we present a
spin-orbit study of Typhon-Echidna. We find that the binary's mutual orbit is inconsistent with a Keplerian orbit; more detailed non-Keplerian fits show that the mutual orbit is rapidly precessing. We measure Typhon's dynamical oblateness, $J_2$, at $\sim10\sigma$ confidence and find that Typhon's rotation pole is $\gtrsim20^\circ$ misaligned with the binary's mutual orbit. Assuming Typhon has a triaxial shape, our results, combined with rotational light curves and thermal measurements from the literature, suggest ellipsoidal semi-axes of $a=93^{+8}_{-6}$ km, $b=84^{+6}_{-6}$ km, and $c=65^{+9}_{-8}$ km. We further investigate the observational consequences of the complex
spin-orbit dynamics, including light curve alteration by axial precession of Typhon and substantial changes to the system's mutual event season. Based on the system's dynamically excited state, we suggest a recent encounter with a
giant planet may have substantially altered the system, potentially consistent with a binary in an early stage of disruption. This hypothesis can be tested with resolved photometric observations of the system. Our investigation highlights how non-Keplerian dynamics enhances our understanding of TNB systems and motivates ongoing observations of TNBs with astrometry, photometry, and
stellar occultations.
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Cosmology and Nongalactic Astrophysics
A Gaussian Covariance Matrix for Joint Pre- and Post-Reconstruction Full-Shape Power Spectrum Analysis
Yuting Wang, Ruiyang Zhao, Gong-Bo Zhao et al. (+1 more)
We apply the Gaussian covariance formalism to develop a semi-analytical covariance model for the joint analysis of pre-reconstruction, post-reconstruction, and cross full-shape
galaxy power spectra. We model the reconstruction-reduced, scale-dependent cross shot noise using displacement-field statistics and introduce a new
estimator that directly measures this term. Using the measured power spectra and the modeled shot-noise predictions as inputs, we construct the Gaussian covariance while accounting for correlations between the pre- and post-reconstruction density fields. We validate the resulting semi-analytical Gaussian covariance against mock catalogues. Using emulator-based parameter inference, we demonstrate that the semi-analytical Gaussian covariance adequately captures the dominant contribution to the covariance structure of the full data vector ($P_{\ell}^{\rm pre}, P_{\ell}^{\rm post}, P_{\ell}^{\rm cross}$). For the joint fit to these three power spectra, it yields cosmological constraints consistent with those obtained using the mock-based numerical covariance over the adopted fitting ranges: $k_{\rm max}=0.18\,h\,{\rm Mpc}^{-1}$ for $P_{\rm pre}$ and $P_{\rm post}$, and $k_{\rm max}=0.12\,h\,{\rm Mpc}^{-1}$ for $P_{\rm cross}$.
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All authors Yuting Wang, Ruiyang Zhao, Gong-Bo Zhao, Kazuya Koyama
Quantum Physics
Generating two-mechanical mode entangled cat states, and steady-state entanglement, in cavity optomechanics in the presence of dissipation
Sanket Das and Jason Twamley
We investigate a dissipation-engineering approach to produce a phase-dependent collective-mode Schrödinger cat state involving two modes. Our model features a single cavity mode that interacts with two spectrally identical mechanical oscillators. Both oscillators are coupled through a phase-dependent hopping interaction. We demonstrate that by adjusting the phase of the
phonon-hopping interaction, one can control the bipartite
entanglement of the phase-dependent two-mode cat state during its generation. Additionally, our study reveals that
phonon interactions act as a tunable parameter, enabling the manipulation of steady-state
entanglement between the bare mechanical modes, even in the presence of environmental effects and thermal excitations. Our scheme provides a feasible approach for the phase-dependent multi mode non-Gaussian states preparation.
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Earth and Planetary Astrophysics
The TASSIE Program. II: Three Close-In Companions Orbiting Sun-Like Stars
T. Plunkett, E. Thygesen, A. A. Cole et al. (+16 more)
We present three southern transiting
giant planet candidates alerted by the Transiting
Exoplanet Survey Satellite (TESS) mission and investigated at the University of Tasmania Greenhill Observatory (UTGO). The candidate
planets are orbiting thin disk G-
dwarf main-sequence
stars with roughly
solar metallicity, possessing orbital periods between 2.9 - 3.3 days and radii of 1.1 - 1.3 $R_{J}$. We performed ground-based follow-up photometry primarily with the UTGO Harlingten 50 cm, then gathered reconnaissance spectra, high angular resolution imaging and high-precision radial velocities to rule out false positive scenarios. We confirmed that two of these systems host true
exoplanets and constrained their masses. TOI-3053b is a typical hot Jupiter, with $M_{3053b} = 0.85 \pm 0.12$ M$_{J}$ and a bulk density of $\rho_{3053b} = 0.64 \pm 0.10$ g cm$^{-3}$. TOI-3278b / HATS-78b is a hot Saturn-mass
planet ($M_{3278b} = 0.30 \pm 0.07$ $M_{J}$) with a highly inflated atmosphere and a low density of $\rho_{3278b} = 0.21 \pm 0.05$ g cm$^{-3}$. The other candidate (TOI-3272.01) remains unconfirmed, but appears consistent with being a hot Jupiter. TOI-3272.01 is notable as a candidate
planet orbiting a potentially young to intermediate age
star, with a rotational analysis indicating an age estimate of $T_{3272} = 1.1 \pm 0.2$ Gyr. These systems add to a growing sample of hot
giant planets from TESS that may provide constraints on the migration pathways and radius inflation of the broader close-in
exoplanet population.
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All authors T. Plunkett, E. Thygesen, A. A. Cole, J. Schulte, J. E. Rodriguez, B. Emptage, J. P. Beaulieu, G. Bakos, J. Hartman, C. Ziegler, K. A. Collins, Z. Csubry, K. Penev, A. Jordán, R. Brahm, L. Mancini, T. Henning, D. J. Radford, P. Evans
Statistical Mechanics
Morphology of frozen labyrinths from irreversible threshold dynamics
Daniel Richard Levy
Majority threshold dynamics, in which each
agent adopts the dominant state in a weighted neighborhood, relaxes a binary field toward consensus or stripes. We study what happens when this rule is made irreversible: each
agent, interacting through a Gaussian kernel on a
lattice, may flip out of its local weighted minority at most once. The reversible form is threshold dynamics of Merriman-Bence-Osher type, an exactly solvable calibration in which interfaces move by mean
curvature with closed-form
lattice pinning and mobility. Irreversibility changes the outcome. From random initial conditions, the one-flip rule freezes balanced non-consensus labyrinths that reversible relaxation drives away. The patterned regime is a window of initial
spin compositions around equal balance, narrowing as the interaction range grows, controlled by a standardized bias whose onset is independent of scale over a fourfold range. The frozen morphology is arrested coarsening: bicontinuous at balance, with a feature width that grows sublinearly and falls below the interaction range at large scales. We determine the mechanism by intervention. Fixing the initial condition while varying the update order shows that the coarse domain layout is deterministic, while the update order enters only in a secondary first-passage race that fine-tunes the wall positions the deterministic dynamics has already set. Those walls are marked by frustration:
agents frozen against their own local field. This signature is identically absent from any reversible relaxation, is overwhelmingly interfacial, and carries almost none of the pattern's large-scale shape.
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Quantum Physics
What meter interference can tell us about the statistics of weak measurements
Holger F. Hofmann, Tomonori Matsushita, Masayoshi Isobe et al. (+1 more)
It is widely assumed that the
quantum fluctuations of the meter readout in a weak measurement make it impossible to identify the contributions originating from the individual values of the physical property observed in the measurement. Here, we show that a careful analysis of the
quantum dynamics of the meter system allows us to identify a universal relation between
quantum interference in the post-selection probability, and
quantum interference in the statistics of the meter readout. The analysis reveals that
quantum interference modifies the readout distribution of the meter in two ways, a
diffusion term that identifies the appropriate operator ordering in the post-selected variance of the observed system property, and a wavefunction-dependent update of the initial meter statistics based on the effect of back action on the post-selection probability. Our results show that the statistical patterns described by meter interference provide important details about the physics of post-selection in weak measurements, allowing us to exclude the possibility of statistical artefacts in the experimental observation of weak values.
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All authors Holger F. Hofmann, Tomonori Matsushita, Masayoshi Isobe, Jonte R. Hance
Biological Physics · Cross-listed from cs.ET
A Quantum Circuit Framework for Protein Ensemble-Level Energetics
Pratik Patil, Bhushan Bonde and Bhaskar Choubey
Proteins occupy heterogeneous free-energy landscapes in which high-
entropy ensembles converge toward compact, low-energy basins with multiple sub-states. Molecular dynamics can access these landscapes at atomic resolution, but exhaustive sampling remains computationally demanding. Meanwhile, most
quantum approaches target only single optimal structures, leaving full ensemble energetic heterogeneity unexplored. We introduce a residue-level, gate-based
quantum circuit framework for coarse-graining
protein thermodynamics. Each amino acid is represented as a two-state
qubit (stabilised vs. excited solvation state) based on residue solvation energetics. A structure-informed
entanglement block then encodes covalent and non-covalent contacts using parameterised controlled gates,
embedding correlations across the residue-interaction network. Sampling the
circuit ($\sim 10^6$ measurements) yields binary thermodynamic microstates used to compute
protein energy distributions, residue-level statistical couplings, energetic sensitivities, and information gains relative to total free energy. We showcase the framework on the
benchmark Trp-cage miniprotein 1L2Y (TC5b) and 9GDL, a disulfide-stabilised Trp-cage-fortified exenatide chimera. For 1L2Y, the
circuit reproduces a structured, folding-funnel-like energy distribution. Comparative analysis with 9GDL reveals shifts in global energy distributions and residue-level stability profiles. Coupling and information-theoretic analyses localise residues associated with ensemble reorganisation, while multi-body couplings show the
circuit resolves both direct and indirect statistical correlations. This framework expands
quantum protein modelling beyond single-structure optimisation toward ensemble-level characterisation, capturing key features of rugged energy landscapes to guide
protein design, mutation mapping, and allosteric pathway identification.
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