Quantum Physics
Fixed-Protocol Amortized MPS Tomography with Conformalized Predictive Uncertainty
Jian Xu, Delu Zeng, John Paisley et al. (+1 more)
Quantum state
tomography is sample-starved, and the states one prepares live on a narrow, learnable
manifold. A $k{=}0$ prior-only control shows that on concentrated families a prior estimate is already near-optimal, so “high fidelity at few measurements” can be family memorization rather than
tomography; genuine measurement-efficiency needs a model that conditions on the measurements and demonstrably uses them. On a shared
matrix-product-state (MPS) core parameterization we study two routes. Approach~A learns a generative prior over MPS cores with measurement-guided posterior inference (gold-standard-validated, but whose few-measurement accuracy the control shows is largely the prior). Approach~B, our main proposal, is a fixed-protocol amortized MPS
estimator trained once with a gauge-invariant fidelity loss; we deliberately do not rest it on a permutation-invariant set encoder (a plain MLP matches it). The decisive lever is the measurement design: motivated by the fact that local reduced density
matrices determine a $\chi$-MPS, conditioning on an informative local Pauli set rather than random strings turns a modest, memorization-prone
estimator into a high-fidelity one ($\approx\!0.95$, up to $+0.59$ over prior-only, decisively passing a shuffled-measurement control). A dropout ensemble, conformally recalibrated, gives $\approx\!90\%$-coverage intervals – including for observables never measured, where a shot-based interval does not exist. Quality holds as the system grows (fidelity $0.90$ at $n{=}10$, gain growing in $n$; $0.88$ at bond dimension $\chi{=}4$), the parameterization is
polynomial (native contraction to $20$
qubits), and we close the loop on IBM hardware ($5$ states at $0.97$ from hardware-measured Paulis).
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All authors Jian Xu, Delu Zeng, John Paisley, Qibin Zhao
Mesoscale and Nanoscale Physics
Tellurium Metasurface Beam Splitter with Pulse Laser-Controlled Anisotropy
Takuto Hiraoka, Mizuho Matoba, Yuta Kobayashi et al. (+5 more)
Laser-programmable optical anisotropy offers a new route to developing reconfigurable metasurfaces without conventional nanofabrication processes. Here, we demonstrate a lithography-free approach based on spatial control of the crystallographic $c$ axis orientation in tellurium (Te) using pulse
laser irradiation. As a proof of concept, we demonstrate a Te metasurface beam splitter by
laser-written optical-axis patterning and experimentally confirm that its optical response is in good agreement with theoretical predictions and numerical simulations. By directly programming the local optical anisotropy, this method enables a simple fabrication process while offering the possibility of rewriting and dynamically reconfiguring device functionality. These features make this approach a promising platform for non-resonant active metasurfaces and other reconfigurable flat-optics applications.
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All authors Takuto Hiraoka, Mizuho Matoba, Yuta Kobayashi, Arata Mitsuzuka, Masashi Kawaguchi, Haruyuki Sakurai, Kuniaki Konishi, Masamitsu Hayashi
Optics
Geometry-Optimized Complex-Domain error-diffusion encoding for Fourier Single-Pixel Imaging
Chongwu Shao, Yue Cao, Wei Zhang et al. (+4 more)
This work proposes a geometry-optimized complex-domain error-
diffusion encoding method for
Fourier single-pixel imaging. Instead of independently binarizing multiple grayscale phase-shifting patterns, the proposed method directly represents each complex-valued
Fourier basis pattern using K (K >= 3) weighted binary patterns while diffusing the residual error in the complex domain. A
geometric interpretation is further established, revealing that the encoding process can be viewed as approximating the
Fourier-basis unit circle by a regular polygon in the complex plane. Based on this
geometric interpretation, practical optimization strategies are developed for K = 3, K = 4, and K = 7. Both numerical simulations and real-object experiments demonstrate consistently superior reconstruction quality compared with conventional phase-shifting dithering.
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All authors Chongwu Shao, Yue Cao, Wei Zhang, Xiaopeng-Jin, Yingran Shen, Shijian Li, Xu-Ri Yao
Applied Physics · Cross-listed from cs.CV
A Nearable Soft Mat Based on Distributed Optical Fiber Sensing for Physiological Monitoring
Vincenzo Lavorgna, Martina Pulcinelli, Andrea Polimadei et al. (+5 more)
Distributed optical fiber sensing (DOFS) combines the advantages of fiber optic sensors, including flexibility, small size, immunity to electromagnetic interference, and high metrological performance, with the capability to transform a single optical fiber into a continuous sensing element for spatially resolved mechanical measurements. Optical frequency domain reflectometry (OFDR), based on Rayleigh backscattering, enables high spatial resolution DOFS measurements, broadening the range of potential sensing applications. However, OFDR based DOFS remains largely unexplored for biomedical applications, despite the need for sensitive, spatially resolved, and conformable sensing interfaces. This study presents a soft DOFS based mat as a large-area interface for physiological monitoring. A single-mode optical fiber was embedded in a flexible silicone
matrix and arranged in a serpentine layout to distribute sensing over the mat surface. With a gage pitch of 2.6 mm, the system provided 2250 sensing sites across the active area at a sampling frequency of 50 Hz. The mat was assessed on six healthy volunteers in a seated nearable configuration on the backrest of a standard office chair. The distributed output enabled two dimensional mapping of the mat response, reflecting back mat mechanical coupling and cardiorespiratory induced perturbations. Respiratory rate and heart rate were therefore estimated and compared with a reference wearable system. The maps revealed physiologically coherent spatial and temporal patterns, while the estimated rates showed good agreement with the reference measurements. These results demonstrate the feasibility of combining large area distributed sensing, spatial mapping, and quantitative cardiorespiratory monitoring within a DOFS based soft nearable interface.
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All authors Vincenzo Lavorgna, Martina Pulcinelli, Andrea Polimadei, Rosaria D Amato, Carlo Massaroni, Michele Arturo Caponero, Emiliano Schena, Daniela Lo Presti
Cosmology and Nongalactic Astrophysics
Cosmology from Nx2pt Analyses of SKAO Wide-Area Surveys
Ian Harrison, Ziad Sakr, Giulia Piccirilli et al. (+7 more)
SKAO surveys will provide an unprecedented window into the large-scale structure of the universe through HI 21cm
galaxy and intensity mapping surveys, and
radio continuum surveys. We present forecasts for the cosmological constraining power of “$N\times2\mathrm{pt}$” analyses – which combine
galaxy clustering,
galaxy weak
lensing,
galaxy-
galaxy lensing signals and 21cm Intensity Maps. By assuming cosmology surveys from an SKA-Mid AA4, we show that such an $N\times2\mathrm{pt}$ analysis will be able to deliver measurements of $\sim1\%$ precision on $\Lambda$CDM cosmological parameters. We also explore dynamical dark energy in the $w_0, w_a$ model, the sum of
neutrino masses $\rm M_\nu$, and the background
curvature $\Omega_{\rm k}$.
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All authors Ian Harrison, Ziad Sakr, Giulia Piccirilli, Chandra Shekhar Saraf, Jacobo Asorey, Benedict Bahr-Kalus, José Fonseca, Marina Migliaccio, David Parkinson, Cora Uhlemann
Materials Science
Impact of Electronic Energy Dissipation on Primary Radiation Damage Formation in Silicon
Nadezda Korepanova, Rafael Nuñez-Palacio and Andrea E. Sand
In this work, we investigate the role of ion-electron coupling in simulations of radiation damage formation in silicon using molecular dynamics simulations within a two-temperature model. We explore predictions of a threshold-free approach to the coupling that accounts for both the electronic stopping and electron-
phonon coupling using a local electron density-based formalism. We compare two different coupling functions across a range of primary knock-on atom energies using two interatomic potentials. Our results demonstrate that the functional form of the ion-electron coupling plays a critical role in determining defect production efficiency, clustering, and recombination, and must therefore be carefully considered for accurate modeling of radiation damage formation. Furthermore, we find that the impact of the coupling in particular on the recombination of defects during the cooling phase of the cascade depends on the choice of interatomic potential, emphasizing the importance of physically grounded descriptions for both electronic effects and atom-atom interactions for reliable radiation damage predictions.
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Quantum Physics
Deployment of Entanglement-Based QKD in Financial Infrastructure
Mirela Selimović, Roman Solar, Jonathan Gruner et al. (+6 more)
We demonstrate the feasibility of
entanglement-based
quantum key distribution (eQKD) in high-security financial infrastructure over a 22 km fiber link with 8 dB loss between two data centers using polarization
entanglement. The fully automated system continuously generated secure keys for four months at an average rate of 63.8 kb/s, which were stored into a key management system and consumed to establish a VPN tunnel. The setup achieved 93.7% total up-time, with no downtime caused by the
quantum optical components. Active polarization control kept the
quantum bit error rate below 2% for 97.4% of the time and timing synchronization based on the entangled
photon pairs' intrinsic temporal correlations achieved sub-300 ps precision. Our standalone system requires neither polarized guide
lasers nor external high-precision time references. These results show practical integration of eQKD into operational financial infrastructure.
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All authors Mirela Selimović, Roman Solar, Jonathan Gruner, Sebastian Mair, Mario Wenzl, Thomas Heine, Matej Pivoluska, Rupert Ursin, Sebastian Philipp Neumann
Geophysics
Pore pressure change during nucleation and slip along experimental faults
Nicolas Brantut, François X. Passelègue and Pierre Dublanchet
In order to clarify the main controlling factors influencing fluid pressure changes in fault zones during the seismic cycle, we conducted laboratory rock friction experiments where fluid pressure was monitored in situ during sequences of quasi-static loading followed by dynamic slip events. The simulated fault was a 30$^\circ$ saw-cut in a Westerly granite cylinder, saturated with water, tested under triaxial conditions. Pore pressure was held constant at the boundaries of the block, but the low hydraulic diffusivity of Westerly granite made the fault hydraulically disconnected from the boundaries. During quasi-static loading while the fault was locked, we observed pore pressure increases which we interpret as poroelastic closure of the fault. During dynamic slip events, pore pressure systematically dropped by amplitudes commensurate to the normal stress drop. A large contribution to the pore pressure drop is interpreted as poroelastic opening of the fault. Deviations from the poroelastic effects are observed: in small events, pore pressure dropped further than anticipated, indicating inelastic dilation. In a few large events, pore pressure dropped less than anticipated, which could be the sign of compaction or thermal pressurisation. Prior to macroscopic slip events, we detect systematic pore pressure decreases by up to around 1 MPa, correlated to the occurrence of inhomogeneous preslip along the fault. Slip nucleation, inferred by kinematic inversion of local strain gauge data, is linked to local slip magnitudes of the order of 1 to 10 $\mu$m, and appears to lead to inelastic dilation. A stability analysis of fault slip including dilatant and poroelastic effects shows that poroelastic coupling tends to compensate normal stress variations, leading to faults operating under mostly constant effective normal stress if conditions are undrained.
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Quantum Physics
Asymmetry-aided measurement-based quantum repeaters and distributed quantum computing with a decoder-free client
Wooyeong Song, Sungyeon Kook, Wonhyuk Lee et al. (+1 more)
Distributed
quantum computation needs to move logical
qubits across lossy optical links, yet this transmission layer is usually designed separately from the computation it serves. We treat the two together by recognizing that a measurement-based
quantum repeater is a two-dimensional code foliated along the transmission axis, so that the dominant channel loss is concentrated on the transmitted sector while the locally measured
qubits are largely spared. Matching a code's distance to this structural asymmetry, we show that a rectangular Bacon-Shor subsystem code transmits a logical
qubit markedly more efficiently than transmission-unaware encodings. Over continental distances, its cost-optimal repeater density is about an order of magnitude lower than that of a recent $[[48,6,8]]$
benchmark at comparable transmission rate, and roughly half that of a symmetric code of equal size. Moreover, we extend the framework to a central-to-client round trip in which a code-level, distance-preserving code switch joins the transmission legs to the client's computation, and joint decoding of the heterogeneous syndrome record at the central node lets distributed
quantum computation proceed with a decoder-free client.
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All authors Wooyeong Song, Sungyeon Kook, Wonhyuk Lee, IlKwon Sohn
Materials Science
Anisotropic hot carrier relaxation mediated by electron phonon scattering in TiN thin films
Hemant Verma, Tzu-Yu Peng, Shyr-Shyan Yeh et al. (+5 more)
Crystal orientations can shape the ultrafast energy relaxations of transition-metal nitride thin films. Here, we investigate the orientation-dependent electron-
phonon (e-ph) mediated relaxation in titanium nitride (TiN) thin films along the [100], [110], and [111] directions by combining first-principles calculations with ultrafast pump-probe transient absorption spectroscopy. Using maximally localized Wannier functions, we evaluate e-ph quasiparticle scattering lifetimes near the
Fermi level and identify a clear anisotropy: The TiN [111] orientation exhibits a longer e-ph scattering lifetime (15.96 fs) than [100] (13.69 fs) and [110] (11.12 fs), indicating reduced intrinsic e-ph scattering strength. Furthermore, we grew quasi-epitaxial, orientation-controlled TiN thin films on MgO substrates. Pump-probe measurements reveals that the population-level relaxation (hot-electron cooling) time also depends on orientations, with [111] films showing a significantly slower decay (110 fs) than [100] (90 fs) and [110] (80 fs). We emphasize that the calculated few-femtosecond scattering lifetimes and the measured few-hundred-femtosecond cooling time respectively represent single-event scattering and collective cooling, yet they exhibit consistent trends. These results demonstrate that crystallographic orientation provides a practical and powerful route to tune e-ph-governed relaxation in TiN thin films, offering essential design guidelines for refractory plasmonic and energy-conversion platforms.
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All authors Hemant Verma, Tzu-Yu Peng, Shyr-Shyan Yeh, Sheng-Chieh Huang, Pritam Sardar, Yang-Hao Chan, Yu-Jung Lu, Chao-Cheng Kaun
General Relativity and Quantum Cosmology
Formation of Trapped Surfaces from Spacelike Initial Data
Xuantao Chen and Sergiu Klainerman
We make use of the free data formalism developed in \cite{CK25,CK26} to provide a direct construction of short-pulse type Cauchy data. The construction of the spacelike short-pulse follows from the local existence result established in \cite{CK26}. The forward integration construction in \cite{CK26} allows us to show that such data can be extended to a set of asymptotically flat Cauchy data. This greatly extends the result of Li–Yu \cite{LiYu}.
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Optics
Chiral lasing via broken parity-time symmetry in bound-state-in-the-continuum metasurfaces
Matthew Parry, Daria A. Smirnova, Andrey A. Sukhorukov et al. (+1 more)
We propose a concept for
chiral lasing from planar metasurfaces that obviates the need for traditional out-of-plane
symmetry breaking by exploiting spatial gain-loss modulation to break parity-time
symmetry. We explain the underlying non-Hermitian physics of this design principle using a coupled-mode model of a four-site plaquette. The
symmetry requirements for such
chiral emission are explained with a general
symmetry analysis based on projection operator
matrices, implemented algorithmically for automated evaluation. This method enables the design of planar metasurfaces capable of emitting nearly-pure circularly polarized light. We apply our analysis to simulations of both symmetric and asymmetric versions of a Fylfot metasurface design and demonstrate that the gain mode at the parity-time symmetric exceptional point exhibits
chiral emission. Lastly, we present a readily manufacturable metasurface made from an InGaAs slab, showing that such a metasurface
laser can be actively tuned from linear to circular polarization.
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All authors Matthew Parry, Daria A. Smirnova, Andrey A. Sukhorukov, Dragomir N. Neshev
Quantum Physics
Which Classicality? Incidence, Simplex, and Product-Rule Tests in Finite Quantum Logics
Karl Svozil
Finite
quantum-logical constructions can appear classical or nonclassical depending on which structure is retained. We distinguish incidence tests based on valuations, colorings, and partition representations; simplex-
embedding tests for specified prepare-and-measure fragments; and operator-functional tests imposing spectral and product rules. We show that the collective GHZ joint measurement is a single Boolean context and becomes nonclassical only when a common assignment of local factors, together with product preservation, is required. For selected labelled ray fragments, we compute state-depolarizing thresholds for a restricted projector-cone factorization and for a specified vector-generated operational closure, separating exact primal–dual certificates from numerical estimates. These values are properties of the stated fragments and noise model, not invariants of the underlying hypergraphs or a universal ordering of contextuality.
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High Energy Physics (Phenomenology)
Neutron tagging of heavy lepton pair production at RHIC and LHC energies
Atacan Fatih Candar and Mehmet Cem Güçlü
We calculated cross sections for $\gamma\gamma \rightarrow \ell^+\ell^-$ ($\ell=e,\mu,\tau$) production in ultraperipheral gold and lead collisions and compare our results with recent measurements from the
STAR, ALICE, ATLAS, and CMS experiments at center of mass energies $\sqrt{s_{NN}}=200$ GeV, $\sqrt{s_{NN}}=2.76 $ TeV, and $\sqrt{s_{NN}}=5.02$ TeV. The calculations are performed within lowest order
quantum electrodynamics (LO QED) using a Monte Carlo technique for calculating the impact parameter dependent probability, and subsequently combined with
neutron emission probabilities associated with Coulomb excitation of the
nuclei. These
neutron emission scenarios are modeled using a Poisson statistics, allowing the cross sections to be categorized into experimentally relevant
neutron classes: 0n0n, 0n1n, 1n1n, 0nXn, XnXn, and inclusive (0n0n+0nXn+XnXn) production. To enable a direct comparison with experiments, fiducial phase space restrictions corresponding to the acceptance of each detector are implemented.
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Materials Science
Anomalous Transverse Response and Multi-Field Ferrialtermagnetic-Ferroelectric Valve with CrSb Flakes
Long Zhang, Xinfeng Chen, Hongfei Liang et al. (+5 more)
Altermagnets combine the zero-stray-field of antiferromagnets with the
spin polarization of ferromagnets, showing great potential for spintronic applications. Here, we propose ferrialtermagnetism as a distinct subclass of altermagnetic family, where
symmetry-inequivalent altermagnetic sublattices possess nonidentical Neel vectors, preventing mutual cancellation of alternating
spin splitting and conferring intrinsic robustness against perturbations. This concept is realized in the three-atomic-layer CrSb (110) flakes, which exhibits
spin splitting of 344 meV, moderate uniaxial
magnetic anisotropy, and high Neel temperature of 657 K. The magneto-optical Kerr and the anomalous
Hall effects are observed. Integrating this ferrialtermagnetic CrSb with ferroelectric Sc2CO2 and Cu spacer, we design an ferrialtermagnetic-ferroelectric valve. This device displays
equilibrium tunneling magnetoresistance and electroresistance of ~10^3%, and non-
equilibrium magnitudes under bias, thermal, or light field reaches ~10^4% with high
spin filtering of 90%. The negative differential resistance and photogalvanic effects, and photocurrent extinction ratio of 283.8 are achieved. These findings establish ferrialtermagnetism as a fertile platform for multi-field-controlled, ultracompact, and self-powered spintronics and electronics.
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All authors Long Zhang, Xinfeng Chen, Hongfei Liang, Jianting Dong, Fei Zou, Yi Yan, Guangqian Ding, Guoying Gao
Atmospheric and Oceanic Physics
Typhoon intensity ReAnalysis (TyRA)
Kosuke Ito, Masataka Aizawa, Udai Shimada et al. (+2 more)
Best-track data have been typically used to explore long-term changes in typhoon intensity over the western North Pacific (WNP). However, the methods used to construct best-track intensities have changed over the past several decades. Several attempts have been made to achieve homogeneous intensity analyses based on the Dvorak method, but their consistency with direct observations can still be improved. This study tries to accurately explain minimum sea-level pressure (MSLP) from aircraft observations during 1981-1986 using CI numbers and other parameters as in Aizawa et al. (2024). Using the optimized coefficients, we reanalyzed MSLP for 1987-2024. The reanalyzed MSLPs were converted into maximum wind speeds using Knaff and Zehr (2007). This Typhoon intensity ReAnalysis (TyRA) exhibited a slightly decreasing trend in the number of intense typhoons, which was not statistically significant. Compared with TyRA, the Joint Typhoon Warning Center (JTWC) best-track contained a larger number of intense typhoons from the late 1980s to the mid-2000s, whereas the Regional Specialized Meteorological Center (RSMC) Tokyo best-track contained a smaller number. In TyRA, typhoons recently weakened over the eastern part of the WNP with some statistical significance. It can be explained by the decrease of mean age of typhoons after typhoon genesis. Large differences among the RSMC Tokyo and JTWC best-track data and TyRA were found for rapid intensification. Furthermore, although previous studies reported that errors in intensity forecasts by the RSMC Tokyo increased in the mid-2000s, the changes in the quality of the RSMC Tokyo best-track data partly explain this.
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All authors Kosuke Ito, Masataka Aizawa, Udai Shimada, Yasuhiro Kawabata, Munehiko Yamaguchi
Quantum Physics
Quantum Multiscale Modeling: A Hierarchy of Algorithms for Complex Chemical Systems
Seenivasan Hariharan, Kareljan Schoutens, Sachin Kinge et al. (+1 more)
Multiscale modeling of complex chemical systems requires
algorithms that operate coherently across electronic, atomistic, mesoscopic, and continuum scales. While
quantum algorithms have been proposed for each regime, no systematic framework exists to compose them across scale boundaries. Here, we identify the conditions under which fault-tolerant
quantum algorithms might preserve scale-specific
quantum advantages. We map
quantum phase estimation,
Hamiltonian simulation with Gibbs state preparation,
quantum random walks, and
quantum partial differential equation solvers onto electronic structure, molecular dynamics, mesoscopic kinetics, and continuum reactor physics, respectively. Crucially, these correspondences do not imply unconditional end-to-end
quantum advantage; speedups depend heavily on state preparation,
memory architectures,
matrix conditioning, and classical readout costs. Six unresolved questions define this composition problem, illustrated via a
quantum hierarchy for \ce{CO} oxidation over \ce{Pt(111)}. We propose viewing inter-scale transfer as a
quantum channel composition problem at the interface of
algorithm design and non-
equilibrium statistical mechanics, and ask whether information loss at scale boundaries is intrinsic to multiscale modeling or merely a consequence of lossy classical transduction between algorithmic layers. The resulting roadmap suggests that multiscale
quantum advantage is governed primarily by the structure of information transfer between algorithmic layers, rather than by performance at individual scales alone.
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All authors Seenivasan Hariharan, Kareljan Schoutens, Sachin Kinge, Lucas Visscher
Quantum Physics
Distributed Semantics for Distributed Quantum Computing
Jun Inoue
We present a
quantum process calculus that can split the system state along process boundaries and follow the
evolution of each process in isolation, without losing information about the joint state-a property we call spatial compositionality. Compositionality is the key to
reasoning about any complex system, yet
quantum process calculi have struggled to provide its spatial kind, which would enable analyzing a system one process at a time. Many a
quantum process calculi have been proposed, but they invariably rely on a global state representation based on state vectors or density
matrices, with no known way to split them without losing information about
entanglement. We propose to model
quantum states with Deutsch-Hayden descriptors instead, which provide a modular representation of
qubit states and their
evolution. We adapt these descriptors to allow arbitrary splitting and merging of the store of
qubits, leading to an unusual process calculus in which
qubit transfer messages carry the actual state of the
qubit, where existing calculi transfer only a reference. The calculus gives localized views of system state visible to each process, which can be assembled back together into the joint state. We define a notion of process equivalence with extensive justification grounded in physics and show a bisimulation whose soundness proof is simplified by spatial compositionality. The calculus can model open systems entangled with external processes, and we demonstrate this capability on a fragment of the BB84 key distribution protocol. This exercise shows that Deutsch-Hayden descriptors can successfully track
qubit movements across process and system boundaries, though it needs help from density
matrices to reason about information flow.
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Computational Physics
Uncertainty-Aware Structure-Property Mapping of Spinodoid Metamaterials via Heteroscedastic Gaussian Process Regression
Minwoo Park, Junseo Park, Mingyu Lee et al. (+4 more)
Spinodoid metamaterials offer a broad, tunable design space for anisotropic mechanical properties, yet their structure-property relationships are commonly treated as representative mappings from cone-angle descriptors to single effective stiffness values. This deterministic view overlooks the
stochastic nature of Gaussian random field (GRF)-based
topology generation, where identical cone-angle descriptors can produce different morphology realizations and property scatter. Here, we present an uncertainty-aware structure-property mapping framework that reinterprets cone-angle descriptors as
stochastic descriptors associated with input-dependent property distributions. Using heteroscedastic Gaussian process regression (GPR), the framework infers input-dependent predictive uncertainty from sparse one-realization-per-point data without requiring empirical variance labels at every design point. The results show that stiffness scatter differs across tensor components according to each component's mechanically active directions, and that parameter sets yielding identical mean stiffness can carry different aleatoric uncertainty. Applying this uncertainty to reliability-based design optimization (RBDO), we show that a deterministic optimum is highly susceptible to constraint violation once morphology-induced variability is considered, and that a homoscedastic RBDO formulation fails to meet the prescribed reliability target - only the heteroscedastic formulation satisfies the reliability target under the heteroscedastic uncertainty evaluation. This establishes uncertainty-aware surrogate modeling as essential for reliability-aware inverse design of spinodoid metamaterials; extending the framework to nonlinear responses remains for future work.
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All authors Minwoo Park, Junseo Park, Mingyu Lee, Hugon Lee, Hanbin Cho, Ikjin Lee, Seunghwa Ryu
Plasma Physics
VSC: A Zero-Dimensional Fusion Design Platform for Multiple Magnetic Configurations
Zekun Wang, Huasheng Xie, Feng Zhang et al. (+2 more)
The VeloAlpha System Code (VSC) is a computational framework for zero-dimensional fusion power-balance studies across five
magnetic-confinement configurations: tokamaks,
magnetic mirrors, field-reversed configurations (FRCs), dipoles, and stellarators. A common power-balance formulation connects fusion production, charged-particle deposition, radiation, transport loss, external heating, and fusion gain, while each configuration retains its own geometry, profile weights, confinement model, and operating constraints. The same solver interface supports both single-point calculations and two-dimensional
plasma operating contour (POPCON) scans, producing fusion and heating powers, gain, radiation and transport losses, geometry quantities, and configuration-specific validity indicators. VSC therefore makes it possible to study how assumptions about density, temperature,
magnetic field, confinement, and geometry shape the accessible operating space of different fusion concepts within one traceable framework. By combining reduced-order physics models with a unified computational platform, VSC enables rapid assessment and comparative analysis of candidate fusion reactor concepts during the early design stage.
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All authors Zekun Wang, Huasheng Xie, Feng Zhang, Jian Bao, Ming Yang
Quantum Physics
Unique temporal scaling dimension for quantum criticality in open systems weakly coupled to environment
Fan Zhong
Probing, understanding, predicting, and controlling the real-time dynamics of
quantum phase transitions in open systems are of pivotal importance to modern condensed matter physics, statistical physics, and
quantum computing, among others. Here it is argued that a distinct temporal renormalization-group
eigenvalue is needed for
quantum criticality in open systems weakly coupled to their finite-temperature environment. This new physics enables the formulation of a general scaling theory that can accurately account for the critical properties including the specific Kibble-Zurek scaling in such open
quantum systems. Remarkably, the critical exponents of time-related quantities are altered nonperturbatively regardless of how weak the coupling is, except for an Ohmic bath. Perspectives for future study are also discussed.
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Quantum Physics
Dynamics of two interacting dipolar two-level systems in a multi-mode electromagnetic cavity: sudden death and revival of the entanglement within the Born-Markov approximation
Loann Quien and Naomichi Hatano
Interacting dipolar two-level systems form a special class of
qubits that interact with a cavity in a particular way. We first prove that the Markovian dynamics of one 1/2-
spin in interaction with a quantised
magnetic field from a multi-mode cavity at thermal
equilibrium is equivalent to a two-level atom interacting in the dipole approximation with the electric field of the cavity. We then use the Born-Markov approximation to study the dynamics of two
spins interacting through the
antiferromagnetic Heisenberg coupling in the same environment. By solving the GKSL equation, we find the exact expression of the density
matrix of the system, with the off-diagonal coherence decay time and
spin relaxation time. The concurrence for the stationary state is explicitly derived for any kind of initial state and the role of the singlet state is brought to light. The temporal
evolution of the concurrence is numerically computed for different initial states, the phenomenon of sudden death and revival of the
entanglement is observed for this dynamics. A detailed analysis of the sudden death and revival of the concurrence is conducted for Werner states, with new analytical results obtained thanks to the solution of the GKSL equation. We finally derive the equations and the stationary concurrence for the XXZ coupling.
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Nuclear Theory
Comparative folding-model study of low-energy elastic scattering and fusion of the $^{12}$C+$^{12}$C and $^{16}$O+$^{16}$O systems
Le Hoang Chien, Dao T. Khoa, Nguyen Hoang Phuc et al. (+2 more)
A density dependent nucleon-nucleon interaction (CDM3YR) has been parametrized based on the original M3Y-Reid interaction, to properly reproduce the saturation properties of symmetric
nuclear matter (NM) in the nonrelativistic Hartree-Fock calculation, with the energy of NM in a good agreement with the microscopic ab-initio results over densities up to three times the saturation density. The real optical potential (OP) of symmetric $^{12}$C+$^{12}$C and $^{16}$O+$^{16}$O systems is then calculated within the double-folding model (DFM), using the realistic densities of $^{12}$C and $^{16}$O
nuclei and CDM3YR interaction, for the optical model analysis of elastic scattering at low energies and determination of the astrophysical $S$ factor of $^{12}$C+$^{12}$C and $^{16}$O+$^{16}$O fusion in the barrier penetration model. The DFM calculation of the real OP for these two symmetric systems was also done using the original (density independent) M3Y-Reid interaction, and that added by a repulsive core suggested by Esbensen et al. to explore the impact of medium effects that are effectively encoded in the density dependence of the CDM3YR interaction.
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All authors Le Hoang Chien, Dao T. Khoa, Nguyen Hoang Phuc, Doan Thi Loan, Nguyen Tri Toan Phuc
Nuclear Experiment
Observation of the centrality-dependent difference in directed flow between charged kaons and $K^{*0}$ resonances in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 14.6, 19.6 and 27 GeV
The STAR Collaboration
We present the measurement of rapidity-odd directed flow ($v_{1}^{\mathrm{odd}}$) for charged kaons, $\phi$
mesons, and $K^{*0}(\overline{K^{*0}})$ resonances in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 14.6, 19.6 and 27 GeV. This study includes the first measurement of the $K^{*0}$ resonance $v_{1}^{\mathrm{odd}}$ in heavy-ion collisions. Our measurement shows a centrality-dependent difference in directed flow between charged kaons and $K^{*0}$ resonances, which becomes more pronounced with increasing collision centrality. In contrast, the difference in directed flow between charged kaons and $\phi$
mesons remains nearly independent of centrality. Although anisotropic flow is thought to be developed in the early stages of the collision, for short-lived resonances such as the $K^{*}(892)$ that experience substantial hadronic re-scattering, it remains unclear to what extent the observed $v_{1}^{\mathrm{odd}}$ reflects genuine partonic collectivity in the early stage, and to what extent it is altered by late-stage hadronic interactions and/or reconstruction effects. The present measurement is crucial for disentangling these contributions and addressing this question. Existing hydrodynamic calculations that include a hadronic afterburner based on the UrQMD model indicate that an asymmetric modification of the $K^{*0}$ yield, due to rescattering, relative to the first-order event plane is required to reproduce the observed difference between $v_{1}^{\mathrm{odd}}$ for charged kaons and $K^{*0}$.
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Computational Physics
Compact and Stable Representation of Real-Frequency Spectral Functions for Machine Learning
Xinyang Dong, Ido Zemach, Lei Zhang et al. (+2 more)
We introduce a compact and stable moment representation for real-frequency Green's functions, hybridization functions, and self-energies for machine-learning applications, avoiding the inefficiency of dense frequency grids as well as the ill-posed analytic continuation of Matsubara approaches. The representation is constructed from Cayley-mapped trigonometric moments with the Jacobian included, which preserve spectral-weight normalization, tie the moment sequence to a positive
matrix-valued spectral measure, and admit a systematic route to a pole representation via ESPRIT. This provides a fixed-dimensional learning target in which physical constraints such as normalization and positivity can be imposed directly. Using a graph-
attention neural network with FiLM conditioning, we
benchmark the representation on single-orbital DMFT,
antiferromagnetic DMFT, and a two-orbital
impurity model. The results demonstrate accuracy matching or exceeding that of direct frequency-domain learning, reliable reproduction of the density and staggered magnetization, stable self-energy reconstruction through Dyson equation inversion, and accurate recovery of
matrix-valued spectra with orbital mixing.
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All authors Xinyang Dong, Ido Zemach, Lei Zhang, Guy Cohen, Emanuel Gull
Materials Science
Temperature dependence of charge-to-spin conversion in rhombohedral (110) bismuth thin film
K. Tatsuoka, N. Fukumoto, S. Sakamoto et al. (+7 more)
The amplitude of charge-to-
spin conversion, namely the
spin Hall effect (SHE), in bismuth (Bi) strongly depends on its
crystal orientation. The conversion efficiency at room temperature in rhombohedral (110) bismuth is notably large as expected from its large
spin-orbit interaction, and such a large SHE is ascribed to the large effective g-factor in bismuth [N. Fukumoto et al., Proc. Nat. Acad. Sci. 120, e2215030120 (2023)]. Despite the successful observation of the large conversion efficiency, a more detailed physical mechanism of the SHE in (110) bismuth is still elusive and under debate. In this work, we investigate the temperature dependence of charge-to-
spin conversion in an epitaxial Bi(110)/Ni
bilayer system using the second harmonic
Hall method, revealing that both
spin Hall conductivity and
spin diffusion length augment with decreasing temperature. This finding suggests that
spin scattering in (110) bismuth is dominated by the Elliott-Yafet mechanism, and the charge-to-
spin conversion is mainly attributed to skew scattering.
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All authors K. Tatsuoka, N. Fukumoto, S. Sakamoto, S. Miwa, Y. Fuseya, J. Fujimoto, R. Ohshima, J. Puebla, Y. Ando, M. Shiraishi
Materials Science
Electric field induced Berry curvature dipole in quasi-one-dimensional Bi$_4$I$_4$
Amiya Mondal and Awadhesh Narayan
The nonlinear
Hall effect in time-reversal symmetric materials offers a powerful probe into
quantum geometry. Here, we investigate the electric-field-tunable nonlinear
Hall response in few-layer $\text{Bi}_4\text{I}_4$ using comprehensive first-principles calculations across both its $\alpha$ and $\beta$ phases. Guided by
symmetry analysis, we track the
evolution of the Berry
curvature dipole (BCD) tensor from the monolayer to the
bilayer configuration under an out-of-plane electric field. While the monolayer features a highly rigid band structure and modest BCD tunability, the
bilayer architecture exhibits substantial field-induced band modifications, including a progressive Rashba splitting and eventual gap closure in the $\beta$ phase. Crucially, this field-tunability allows substantial enhancement of the BCD magnitude relative to the monolayer counterpart. Our findings establish quasi-one-dimensional bismuth halogenides as a promising platform for engineering nonlinear
Hall response.
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Optics
Leveraging Raman response in X-cut thin-film lithium tantalate for ultrabroadband combs and polychromatic visible light
Xin Wang, Mingkun Xiao, Min Sun et al. (+9 more)
X-cut thin-film lithium tantalate (TFLT) offers a unique combination of third nonlinearity, electro-optic effects, and a high optical damage threshold. However, its strong Raman response has historically hindered broadband Kerr comb generation. Here, we leverage this inherent Raman response by engineering coupling-defined dissipation. This allows us to reconfigure the relative thresholds of Raman and Kerr processes without modifying the intrinsic microresonator dispersion. Through this coupling-engineered threshold control, we can deliberately access distinct comb states, ranging from pure Kerr combs to Raman-Kerr synergistic broadband combs. We demonstrate a Kerr comb spanning 450 nm and a Raman-Kerr comb spanning 650 nm, representing the broadest combs reported to date on X-cut TFLT platforms. Moreover, in strongly coupled devices, we show that a single near-infrared pump can generate visible emission across multiple bands (from violet to red) via cascaded second sum-frequency processes. Our work demonstrates that a strong Raman response can be transformed from a parasitic competitor into an enabling mechanism for achieving broader comb spectra and generating polychromatic visible light. This work establishes X-cut TFLT as a powerful monolithic platform for nonlinear light sources, electro-optic functions, and complex photonic systems.
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All authors Xin Wang, Mingkun Xiao, Min Sun, Ronghong Gao, Yuqi Chen, Zhengshun Lei, Xun Zhang, Wenfeng Zhou, Jintian Lin, Yikai Su, Xingchen Ji, Yong Zhang
Astrophysics of Galaxies
A Compact Proto-group at $z \sim 5$: A Massive Galaxy Caught in Formation
Ronaldo Laishram, Yusei Koyama, Fengwu Sun et al. (+11 more)
We report the discovery of SCGG-z5, a compact
galaxy proto-group at $z = 4.97$ in the MACS0416 field, identified from the SAPPHIRES Early Data Release. Six members are spectroscopically confirmed via H$\alpha$ emission, spanning $4.96 \leq z_{\rm spec} \leq 4.98$ within a projected diameter of $\sim16$ pkpc. Spectral energy distribution (SED) fitting yields individual
stellar masses $8.4 \leq \log(M_*/M_{\odot}) \leq 9.8$, a total group
stellar mass of $\log(M_*/M_{\odot}) = 10.07 \pm 0.04$; three of the six members lie above or on the
star-forming main sequence at $z \sim 5$, by up to $0.5$ dex. Pixel-by-pixel analysis reveals diverse resolved radial
star-formation profiles: three members show declining specific SFR radial profiles and outward-rising
stellar age gradients, consistent with inside-out
stellar mass growth, while the most massive member shows a tentative inverted sSFR profile suggestive of reduced central
star formation. The line-of-sight velocity dispersion over all six members is $\sigma_v = 375^{+55}_{-195}$ km s$^{-1}$. The projected mass
estimator yields $\log(M_{\rm PM}/M_{\odot}) \approx 12.30^{+0.30}_{-0.25}$, consistent with a dark-matter-dominated group
halo. EAGLE simulations of structurally similar groups predict full coalescence by $z \sim 3$–$4$, with the merged remnant reaching $\log(M_*/M_{\odot}) > 11$ by $z \sim 1$, consistent with SCGG-z5 representing a rare pre-coalescence phase of early massive
galaxy formation, possibly tracing the assembly of a future brightest group or cluster
galaxy.
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All authors Ronaldo Laishram, Yusei Koyama, Fengwu Sun, Takahiro Morishita, Yoshinobu Fudamoto, Haruka Kusakabe, Jakob M. Helton, Xiaojing Lin, Tadayuki Kodama, Eiichi Egami, Kosuke Takahashi, Ryo Albert Sutanto, Novan Saputra Haryana, Zhengyi Chen
Optics
Abnormal motions of optical vortex-antivortex-coupled wavepackets in the parabolic potential
Haolin Lin, Junhui Jia, Chunhao Liang et al. (+4 more)
The (quasi)particles or structured wavepackets in
parabolic potential exhibit well-known harmonic oscillations, typically described by the Lissajous equations. However, such conventional harmonic laws rely on a fundamental assumption that the different constituent components of the (quasi)particles or wavepackets do not interact. Here we challenge this paradigm, by taking advantage of intrinsic couplings among distinct constituents-specifically by leveraging nontrivial couplings between
vortices and antivortices embedded in a spatially structured wavepacket. We demonstrate theoretically and experimentally abnormal motions by considering two different optical waveforms. For a
vortex-antivortexcoupled dipole mode, we reveal counterintuitive propagation regimes, including periodic annihilation and regeneration of the dipole, its non-orbital motion and realization of a critical
equilibrium state without nonlinearity. For a circular chain of
vortices with an antivortex set at the center, we successfully tune the oscillation frequency of the overall configuration in the potential, thus disobeying the classical Lissajous trajectories, by precisely engineering the nonlocal
vortex-antivortex couplings. Since the harmonic oscillations have been proven to be fundamental physical phenomena in distinct disciplines and led to numerous important applications, our demonstrations provide different opportunities to trigger considerable investigations and potential applications, by leveraging the underlying anomalous motions of the
vortex-antivortex-coupled wavepackets in the
parabolic potential.
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All authors Haolin Lin, Junhui Jia, Chunhao Liang, Yanwen Hu, Boris A. Malomed, Yangjian Cai, Shenhe Fu