Quantum Physics
A General First- and Second-Order Numerical Solver for Non-Markovian Quantum State Diffusion
Zhenning Cai and Quanhui Zhu
The numerical simulation of non-Markovian open
quantum systems based on the non-Markovian
quantum state
diffusion (NMQSD) equation is complicated by functional derivatives with respect to the
stochastic process. A general numerical framework that directly treats these functional derivatives without relying on prescribed decompositions of the bath correlation function is still lacking. In this work, we derive an analytical solution of the linear NMQSD equation that reveals three elementary structures of the non-Markovian
stochastic dynamics:
stochastic propagation, functional-derivative insertion, and
memory pairing. Based on this structure, we construct a general auxiliary-state framework for arbitrary bath correlation functions. The framework separates the numerical construction into time discretization,
memory quadrature, and hierarchy truncation. We then construct first- and second-order schemes and provide diagrammatic transition rules for their explicit implementation. Numerical results verify the expected temporal accuracy and demonstrate the applicability of the proposed methods to different bath correlation functions and multi-level
quantum systems.
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Superconductivity
Nonlocal Majorana polarization in non-Hermitian topological superconductors
Arjun S. Kumar, Jorge Cayao and Oladunjoye A. Awoga
The nonlocal Majorana polarization, defined as the product of the expectation values of the particle-hole operator at opposite halves of the system, has been shown to be a reliable topological indicator that determines the presence and quality of Majorana zero modes in Hermitian topological superconducting setups. In this work, we extend the concept of nonlocal Majorana polarization to the non-Hermitian realm by taking into account the biorthogonal eigenstates and demonstrate its utility by exploring distinct non-Hermitian superconducting systems. In particular, we show that the Majorana polarization can distinguish between Majorana zero modes, trivial zero-energy states, and exceptional points in non-Hermitian
superconductors. Also, we introduce the concept of nonlocal Majorana polarization sensitiviy for characterizing the contribution of non-Hermiticity to Majorana polarization. As a byproduct, we find that non-Hermiticity enhances Majorana zero modes robustness, a property captured by the nonlocal Majorana polarization.
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Materials Science
Imaging the Néel Vector in Two-Dimensional Antiferromagnets using Antisymmetric Compton Scattering
Wuxuan Li, Zhuocheng Lu, Jingshan Qi et al. (+2 more)
We demonstrate that antisymmetric Compton scattering can detect both the switching and the continuous rotation of the Néel vector in two-dimensional (2D) antiferromagnets. By probing magnetoelectric (ME) multipoles, which couple electric and
magnetic dipoles, this approach overcomes the limitations of conventional techniques that rely on a finite net magnetization. Using a group-theoretical decomposition of the staggered moments in 2D MnPS$_3$ into irreducible representations, combined with first-principles calculations, we show that the antisymmetric Compton profile (ACP) is highly sensitive to the Néel vector orientation: it reverses sign under Néel vector reversal and exhibits distinct anisotropies under in-plane rotation. These results establish the ACP as a versatile probe of
antiferromagnetic (AFM) order and magnetoelectric phenomena in van der Waals materials.
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All authors Wuxuan Li, Zhuocheng Lu, Jingshan Qi, Hua Wang, Kai Chang
Mathematical Physics
Notes on a paper by F. Génot and B. Brogliato on the Painlevé paradox
Stefano Pasquero
We reconsider the analysis of the Classical Painlevé Problem developed by F. Génot and B. Brogliato ([1] New results on Painlevé paradoxes. - European Journal of Mechanics-A/Solids, 18(4):653{677, 1999), focusing on the consistency of their results with Galilean invariance. We show that certain conclusions concerning the dynamical
evolution of the mechanical system are not invariant under changes of Galilean observer and therefore cannot, in their present form, be interpreted as intrinsic properties of the system. In particular, we show that the classi?cation of motion states depends on the observer through the velocity{dependent characterization of the frictional constraint, and we trace the origin of this dependence to the Galilean velocity-addition
theorem. We present and discuss possible reformulations of the model aimed at restoring observer-invariant descriptions of the problem.
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Mesoscale and Nanoscale Physics
Twisted Multilayer Graphene: Superperiodicity and quasicrystals
Pedro Alcázar Guerrero
This thesis investigates how superperiodicity, quasiperiodicity, and disorder shape electronic and
spin transport in
graphene-based systems, with an emphasis on experimentally relevant length scales and realistic atomistic modeling. Using large-scale real-space
quantum-transport methods, it first establishes controlled transport fingerprints that distinguish conventional Bloch propagation in periodic structures from the anomalous dynamics induced by quasiperiodic modulations. Building on this framework, the thesis analyzes magic-angle twisted
bilayer graphene and shows that, within a finite disorder window where flat-band features remain robust, moderate Anderson disorder can counterintuitively enhance the mean free path. This disorder-induced delocalization is further linked to changes in the
quantum metric extracted from optical conductivity, revealing a direct connection between transport, electronic geometry, and the real-space extent of the underlying states. The study then turns to
graphene quasicrystal approximants and hybrid multilayer stacks, identifying sub-ballistic transport and self-similar localization patterns as signatures of quasicrystalline order, while also demonstrating their strong fragility against disorder and interlayer proximity effects. Finally, the thesis addresses
spin transport in suspended monolayer
graphene, showing that atomic-scale corrugations generate short-range fluctuating Rashba fields that can limit
spin lifetimes to the nanosecond range even when charge transport remains close to ballistic. Taken together, these results provide a unified picture of how geometry, disorder, and structural complexity govern transport phenomena in twisted and corrugated
graphene systems.
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Plasma Physics
Polaris: a flexible stellarator demonstration experiment with simple modular coils
Simon P. H. Vincent, Joaquim Loizu, Matthieu Toussaint et al. (+14 more)
We present the design, construction, and first
plasma experiments of Polaris, a new small-scale stellarator experiment (major radius R ~ 0.4 m) located at the Swiss
Plasma Center. Polaris consists of a relatively large
vacuum vessel (~0.5 m^3) predominantly made of glass windows and inside which different sets of
magnetic coils can be installed. A first modular coil configuration has been designed with six identical, circular, water-cooled copper coils toroidally arranged in an optimal way so that they generate a large volume of
magnetic surfaces and rotational transform in
vacuum (iota ~ 0.3). The total current in each coil goes up to ~ 5 kA, producing a
magnetic field on-axis of B ~ 0.03 T. An RF
antenna specifically designed to operate in
vacuum delivers up to 2.5 kW of power to produce
plasma via inductive coupling and electron-impact ionization. We present the engineering solutions adopted for the design of Polaris and illustrate the great experimental flexibility it enables. Time-averaged values and fluctuations of
plasma density, electron temperature, and floating potential are measured at various toroidal locations, providing insights into the
plasma equilibrium, electrostatic
turbulence, and associated transport. The glass
vacuum chamber of Polaris additionally provides unprecedented optical access to the entire
plasma volume. With its original, flexible design, Polaris is a 'stellarator fish-tank', allowing interchangeable coil sets and exploration of various
magnetic configurations. Furthermore, its low-temperature, low-density, high-neutral-pressure
plasmas are relevant to stellarator edge physics, making Polaris a first-of-kind testbed for the fundamental investigation of stellarator edge-relevant physics.
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All authors Simon P. H. Vincent, Joaquim Loizu, Matthieu Toussaint, Rémy Jacquier, Jérémy Salm, Philippe Guittienne, Matias Habib, Idil Sonmez, Christopher B. Smiet, Erol Balkovic, Rogerio Jorge, Alan G. Goodman, Ivo Furno, Christian Moura, William Matthey-Dorey, Steve Couturier, Frédéric Dolizy
High Energy Physics (Phenomenology)
Singly heavy tetraquarks
Jun-Jie Liu, Zhi-Biao Liang, Feng-Xiao Liu et al. (+3 more)
In this work, we carry out a systematic study of the spectra of the $1S$-wave states for the whole singly-heavy tetraquark systems within a semi-relativistic hybrid
quark potential model, in which both the one-
gluon exchange (OGE) and one-
boson exchange (OBE) interactions are included. Furthermore, the fall-apart decays are evaluated with the
quark exchange model by combining the obtained spectra. It is found that besides the OGE potentials, the OBE potentials play crucial roles for describing the spectrum. All of our obtained states lie far above the lowest dissociation
meson-
meson threshold. They are compact states with relatively narrow fall-apart widths $\sim 1-120$~MeV. The $D_{s0}(2317)$, $D_{s1}(2460)$, $T_{b\bar{s}}(5568)$, and $T_{c\bar{s}}(2327)$ resonances reported from experiments cannot be explained as compact tetraquarks. While the $T_{\bar{c}\bar{s}0}(2870)$ and $T_{c\bar{s}0}(2900)$ favor the tetraquark states with $IJ^P=00^+$ and $10^+$, i.e. $T_{(\bar{c}\bar{s}[ud])0^+}^0(2919)$ and $T_{(cn\{\bar{s}\bar{n}\})0^+}^{1}(2922)$, respectively. More singly-heavy tetraquark states have good potentials to be observed in some of their dominant decay channels in experiments.
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All authors Jun-Jie Liu, Zhi-Biao Liang, Feng-Xiao Liu, Mu-Yang Chen, Xian-Hui Zhong, Qiang Zhao
Quantum Physics
Quantum Teleportation toward the Quantum Internet: A Concise Review
Yang-Bin Ma, Yun-Ru Fan, Ri-Yao Song et al. (+8 more)
Quantum networks play a pivotal role in
quantum information science, which not only provide a secure communication platform for remote access to
quantum computers but also serve as the strategic core for achieving large-scale
quantum information processing, forming the foundational infrastructure for the future global-scale
quantum internet.
Quantum teleportation, which enables the transmission of unknown
quantum states over long distances by employing
quantum entanglement together with classical communication, is essential for the distribution of
quantum resources in the construction of the global-scale
quantum internet. To realize a global-scale
quantum internet,
quantum repeater protocols represent one of the most promising approaches for enabling
quantum communication between any nodes. This concise review presents representative experimental demonstrations of
quantum teleportation for constructing
quantum networks across different physical platforms. Along this trajectory, the review discusses current challenges, open issues, and future perspectives toward scalable and practical
quantum internet.
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All authors Yang-Bin Ma, Yun-Ru Fan, Ri-Yao Song, Ya-Zhou Zhao, Yi-Ye Liu, Si Shen, Zi-Hao Zhan, Yan-Yu Wei, Kai Guo, Guang-Can Guo, Qiang Zhou
Optics
Observation of biased random-flux-induced topological phase transition in gyromagnetic photonic crystals
Hai-Xiao Wang, Chongyang Li, Xianmu Wu et al. (+5 more)
The interplay between disorder and topological states has attracted growing interest. While previous studies have primarily addressed the effects of
geometric or potential randomness, the exploration of topological phase transitions driven by random-flux remains experimentally elusive. Here, we report the first experimental realization of topological phase transitions driven by biased random-flux in gyromagnetic photonic
crystals. By stochastically orienting the magnetization of constituent gyromagnetic rods, we implement a disordered Haldane model in which the sign of the next-nearest-neighbor hopping phases is randomly distributed. We demonstrate that the bulk band gap closes when the densities of positive and negative flux are balanced, i.e, restoring time-reversal
symmetry in a statistical sense, and reopens when a net positive or negative flux is introduced. Microwave near-field measurements directly visualize the reversal of
chiral edge states, confirming a transition between distinct topological phases. Our results establish a unique disorder-driven mechanism for realizing topological phase transitions and deepen our understanding of the interplay between disorder and topological phases in bosonic systems.
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All authors Hai-Xiao Wang, Chongyang Li, Xianmu Wu, Ziyao Wang, Yongmei Wang, Junhui Hu, Shiwei Tang, Zhen Gao
Soft Condensed Matter
Reciprocal theorem for ion-releasing colloidal particles
Evgeny S. Asmolov and Olga I. Vinogradova
We describe a generalization of the reciprocal
theorem for particles suspended in electrolyte solutions and subjected to an electric field that could be either applied or emerged spontaneously.
Attention is focused on catalytic colloids that release ions. The power of the generalization is to capture the effect of formation of a secondary cloud around a catalytic particle, which is equivalent to accounting for an excess charge $Q$ of a system. Our results show that the propulsion speed of catalytic particles has an extra contribution proportional to $Q$ and an external field $E_{\infty}$. The derived equation for $Q$ reveals that its sign is defined by the difference in the ion diffusivity and the magnitude is controlled by the average flux of ions from the surface. We demonstrate the application of the generalized
theorem to electro- and diffusiophoresis of homogeneously releasing ions passive particles, as well as to a self-propulsion of inhomogeneous active particles (microswimmers). It is shown that whilst in some situations the extra term in the reciprocal
theorem vanishes or has a little effect on the particle mobility, in many others it may dramatically change its magnitude, and even sign. In addition, the relevance of our results for microswimmer interactions is discussed briefly.
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Solar and Stellar Astrophysics
A systematic study of quiescent and outburst properties of X-ray-bright young stellar objects using XMM-Newton
Koki Sakuta, Ikuyuki Mitsuishi, Seiya Sasamata et al. (+6 more)
Young
Stellar Objects (YSOs) exhibit strong X-ray emission, widely attributed to
magnetic reconnection and magnetospheric
accretion; however, owing primarily to limited
photon statistics, observational tests of these mechanisms have often relied on simplified analyses, leaving room for more precise constraints on their emission processes. We aim to derive the X-ray properties of X-ray-bright YSOs selected from multiple
star clusters and investigate their emission mechanisms through an approach from multiple perspectives based on timing and spectroscopic analysis. We performed a systematic search of XMM-Newton archival observations and constructed a sample of 51 X-ray-bright YSOs for timing and spectroscopic analyses. We identified quiescent and outburst phases through timing analysis, performed phase-resolved multi-temperature spectroscopy. Multi-temperature
plasma structures are detected in both quiescent and outburst emission. The relationships among the timing and spectral parameters are broadly consistent with a
magnetic-reconnection scenario. Comparison with
Gaia DR3
stellar parameters suggests that magnetospheric
accretion alone has difficulty explaining most of the fitted X-ray temperatures, although the coolest model components with $kT \lesssim 0.3$ keV may include an
accretion-shock contribution. After separating these low-temperature components, the remaining quiescent components show a clearer positive correlation in the $EM$–$kT$ plane, with
magnetic-loop lengths distributed around $10^{12}$ cm. Neupert-like behavior, the temporal
evolution of temperature and emission measure, the Rossby-number activity relation, and positive correlations between quiescent and outburst properties all suggest that
magnetic reconnection plays a key role in both phases.
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All authors Koki Sakuta, Ikuyuki Mitsuishi, Seiya Sasamata, Daigo Nonaka, Mai Yamashita, Shin Toriumi, Takato Tokuno, Yohko Tsuboi, Hiroshi Kobayashi
Astrophysics of Galaxies
From compact jets to extended lobes: radio morphologies of distant quasars at z > 4
K. É. Gabányi, M. Kunert-Bajraszewska, A. Krauze et al. (+9 more)
High-
redshift quasars play an essential role in studying the growth and
evolution of supermassive black holes and active
galactic nuclei (AGN).
Radio-loud
quasars additionally enable us to investigate the interactions between the jets and their environment. We aimed to reveal the
radio morphology of three
radio quasars at
redshifts z>4 that contain milliarcsecond (mas) scale compact
radio features according to previous very long baseline interferometry (VLBI) observations, but show significant flux density at arcsecond scales, indicating the presence of extended
radio structure that cannot be sampled by the highest-resolution observations. We analysed
radio interferometric data obtained at various angular resolutions and multiple frequencies, including observations made by the international Low-Frequency Array and the enhanced Multi-Element Remotely-Linked Interferometer Network. We also re-imaged archival European VLBI Network observations of our targets. Two
quasars (J0813+3508 and J1231+3816) exhibit complex
radio structures with hotspots, extended to tens of kpc. They resemble Fanaroff–Riley II-type
radio galaxies with extremely bent jet morphology. The third object (J1548+3335) shows a one-sided structure of $\lesssim 10$ kpc size. There was no sign of relativistic boosting at its previous mas-scale resolution
radio observations. Its
radio power and (inferred) linear size derived from the lower-resolution observations are similar to the known high-power compact steep-spectrum sources. We found that the previously detected mas-scale compact
radio features are related to the centres of the AGN or in one case to one of the hotspots in an extended lobe.
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All authors K. É. Gabányi, M. Kunert-Bajraszewska, A. Krauze, S. Frey, M. Krezinger, Z. Paragi, H. Cao, T. An, L. I. Gurvits, K. Perger, T. Sbarrato, K. Rozgonyi
Statistical Mechanics
Logarithmic Aging Diffusion from a Multiplicative Event Clock: Rare Event Statistics, Ultraslow Transport, and Ensemble-Time Inequivalence
Chunyan Li, Zheng Li, Yueyan Li et al. (+2 more)
Logarithmic time dependences occur in many aging materials, but neither a $\ln t$ relaxation law nor a $1/t$ event rate uniquely identifies the underlying
stochastic mechanism. We examine a specific log-aging process defined by iterating the age-conditioned forward-recurrence law after every event. This rule makes the event times multiplicative: the logarithmic ratios $U_n=\ln(T_{n+1}/T_n)$ are independent and identically distributed with an explicit non-exponential density. Consequently, both the mean and the variance of the event count grow linearly with $\ln(t/t_0)$, while the density of the $n$th event time has a log-normal central sector and a fixed-$n$ algebraic far tail. These clock statistics generate logarithmic drift and spreading, an Einstein relation under local detailed balance, and ultraslow transit and target-survival laws. They also separate trajectory reproducibility from ensemble–time equivalence: the relative scatter of the time-averaged mean-square displacement decays as $1/\ln(T/t_0)$, although its mean does not converge to the ensemble lag MSD. We distinguish the exact event-level construction from its
diffusion-limit generalized Fokker–Planck and random-clock subordination representations, and from a generalized-Langevin closure that can match selected responses and covariances but need not reproduce event counts or rare-duration statistics. The proposed clock is therefore tested not by a single logarithmic curve, but by the joint, no-refitting consistency of multiplier, count, transport, first-passage, and finite-window observables.
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All authors Chunyan Li, Zheng Li, Yueyan Li, Haiwen Liu, X. C. Xie
Disordered Systems and Neural Networks
Relaxation of quenched structural glasses: descent in a stiffening caging potential over inflection-point 'speed bumps'
Ting Qu, Deng Pan and Yuliang Jin
The slow energy relaxation in quenched glasses is a ubiquitous yet poorly understood phenomenon. Despite extensive study, the microscopic origin of the observed power-law decay remains debated, with proposed mechanisms ranging from saddle-point slowdown and marginal stability to coarsening of localized excitations and
phonon dynamics. Here, by simulating gradient descent in archetypal structural glass formers, we show that none of these scenarios can account for our data. Instead, the power-law behavior emerges from a remarkably simple caging effect: each particle experiences an effective stiffening potential that arises from many-body confinement and diverges at a characteristic cage size. This mechanism analytically yields the observed power-law decay and is quantitatively reproduced by a minimal single-particle cage model with fixed neighbours, demonstrating that collective relaxation modes are not essential. The dynamics is punctuated by fluctuations as the system rolls through inflection points on the energy landscape, which act as `speed bumps' but do not affect the overall power-law behaviour. In contrast to mean-field
spin glass theory, we find no characteristic temperature that separates distinct dynamical regimes; state following within a given glass basin occurs universally for all initial temperatures whenever the system is sufficiently close to the inherent structure. Our results establish a complete physical picture of gradient descent dynamics in typical structural glasses.
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Mesoscale and Nanoscale Physics
Van Hove singularity-driven giant Nernst signal in twisted double bilayer graphene
Ujjal Roy, Monosij Roy, Unmesh Ghorai et al. (+8 more)
Twisted
graphene layers host van Hove singularities (vHSs), peaks in the electronic density of states, thought to drive exotic phases in moiré materials, but their effect on thermal transport has remained unclear. Here we show that vHSs in twisted double
bilayer graphene (tDBLG) generate an unusually large Nernst signal-the transverse voltage produced by a longitudinal temperature gradient in a
magnetic field. The pronounced Nernst peaks at the vHSs of the conduction and valence bands of tDBLG are tunable by an electric field with a maximum value of $\sim 40$ $\mu V K^{-1} T^{-1}$ at $\sim 1$ $K$, which is comparable to the best-known Nernst materials. Our theoretical calculations show that the large enhancement of the Nernst signal arises from the Lifshitz transitions around the vHSs. These findings establish the Nernst effect as a sensitive probe of
Fermi-surface
topology in moiré materials, and identify a universal thermoelectric signature of van Hove singularities.
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All authors Ujjal Roy, Monosij Roy, Unmesh Ghorai, Arkaprava Mukherjee, Ravi Kumar, Kenji Watanabe, Takashi Taniguchi, Nandini Trivedi, Rajdeep Sensarma, Subroto Mukerjee, Anindya Das
Quantum Physics · Cross-listed from cs.DC
QCOEM: Quantum Cloud Orchestration with Evolutionary Multi-Objective Optimization
Tam N. Pham, Hoa T. Nguyen and Quan Le-Trung
Quantum cloud platforms need to dynamically orchestrate workloads across heterogeneous
quantum computation backends whose noise profiles,
qubit topologies, and queues vary over time. Existing orchestrators use noise-agnostic heuristics that ignore backend-specific errors, causing reduced execution fidelity, load imbalance, and frequent rescheduling. To address these challenges, we propose QCOEM - a
Quantum Cloud Orchestration framework that leverages Evolutionary
algorithms for Multi-objective optimization of
quantum task scheduling. We compare NSGA-II and NSGA-III for jointly minimizing mean completion time, execution error rate, and load imbalance. To select schedules from a non-convex Pareto front, we apply an Augmented Achievement Scalarization Function (AASF) as a preference-based decision rule that maps the Pareto set to a single dispatchable schedule aligned with user priorities. Our extensive performance evaluation in a heterogeneous
quantum cloud environment shows zero task rescheduling and about 30% higher mean fidelity than noise-agnostic heuristics, while maintaining bounded scheduling overhead. The experiment results indicate that our QCOEM framework can deliver stable, high-fidelity execution and lightweight resource management for
quantum cloud computing.
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Quantum Physics
Quantum teleportation over a field-deployed hollow-core fibre network
Ri-Yao Song, Ya-Zhou Zhao, Yun-Ru Fan et al. (+8 more)
When a
photon and one member of an entangled
photon pair are jointly projected onto a Bell-state measurement (BSM), the
quantum state of the
photon can be transferred to the distant partner of the pair without physically transmitting this information carrier. In real-world deployment, however, teleportation performance is fundamentally bottlenecked by
quantum channel impairments, such as loss, noise, and fluctuations, which induce severe decoherence and degrade fidelity. This vulnerability is further exacerbated in scenarios with intense classical data traffic or background light. Realizing scalable
quantum networks, therefore, hinges on developing advanced channel architectures capable of supporting both high-fidelity
quantum operations and high-capacity classical communications within a shared infrastructure. Towards this end, hollow core fibre (HCF) offers a promising
quantum channel resource by combining free-space-like weak light-matter interaction with the stability of fibre-based systems. Here, utilizing a field-deployed metropolitan HCF network spanning three spatially separated nodes in Chengdu, we achieve
quantum teleportation with an intermediate BSM under co-propagating classical traffic. Crucially, the HCF links preserve the long-term indistinguishability of photonic
qubits without active stabilization, and exhibit a Raman noise approximately three orders of magnitude lower than that of standard solid-core counterparts. This noise suppression enables robust
quantum teleportation even alongside classical launch powers up to 160 mW. Our findings establish a classical-data-compatible framework for
quantum networking over deployed fibre infrastructure and offer a wavelength-agnostic, plug-and-play, and free-running pathway toward the
quantum internet.
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All authors Ri-Yao Song, Ya-Zhou Zhao, Yun-Ru Fan, Yang-Bin Ma, Yan-Yu Wei, Si Shen, Hao Li, Li-Xing You, Kai Guo, Guang-Can Guo, Qiang Zhou
High Energy Astrophysical Phenomena
Residual Galactic binary foreground in LISA stochastic gravitational-wave background inference: source power concentration and spectral degeneracy
Ruo-Yu Guan and Yan Wang
Galactic compact binaries are expected to form a dominant millihertz foreground for the
Laser Interferometer Space
Antenna (LISA), and residual foreground power can bias
stochastic gravitational-wave background (SGWB) inference or increase its uncertainty. Using the LISA Data Challenge 2A (LDC2A) injections and the Erebor injection-recovery match, we construct a catalog residual spectrum from 0.4 to 6.0 mHz. We distinguish two effects. The first is the departure from Gaussianity of a sum of source signals with independent random phases, quantified by its excess kurtosis; the second is the spectral degeneracy between the residual and the SGWB in the mean binned power. Source discreteness determines the excess kurtosis of this sum, but instrumental noise and fiducial SGWB power strongly reduce its magnitude in most bins. We quantify this degeneracy with a local Fisher information
matrix for the SGWB amplitude $\Omega_0$ and the residual-power factor $\beta$. For a frequency-independent SGWB with $\Omega_0=10^{-11}$ and residual power distributed uniformly over the
Fourier frequencies within each bin, marginalizing over $\beta$ increases the $\Omega_0$ uncertainty by $13.6\%$ with the Gaussian
Fourier-amplitude covariance and by $13.8\%$ with the finite-source diagonal random-phase covariance. Under the Gaussian
Fourier-amplitude covariance, the largest allowed prior standard deviation on $\beta$ that limits this increase to $10\%$ is $0.0073$. With this covariance recomputed at each fiducial amplitude, the uncertainty increase ranges from $12.7\%$ to $20.7\%$ over $10^{-13}\leq\Omega_0\leq10^{-10}$. The residual-SGWB spectral degeneracy persists under alternative distributions of residual power over
Fourier frequencies and diagonal covariances, while omitting the residual induces a systematic bias in the fitted SGWB amplitude.
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Quantum Physics
Detecting quantum phase transitions via shallow variational quantum circuits
Ching-Yu Huang and Min-Fong Yang
Mapping
quantum phase diagrams through classical simulation is notoriously resource-intensive, as even small systems far from the thermodynamic limit demand prohibitive computational effort. The variational
quantum eigensolver (VQE) offers a compelling alternative, exploiting approximate ground states to distinguish phases. An appealing proposal, dubbed as Delta-VQE, determines critical points by contrasting variational energies optimized from reference states of distinct phases. Intriguingly, the diagnostic sharpens as
circuit depth decreases, highlighting its promise as a resource-conscious probe of
quantum criticality. To probe the broader applicability and underlying mechanisms of this approach, we investigate the one-dimensional transverse-field Ising model with a three-
spin cluster interaction, a setting in which the Ising transitions are generally situated beyond the self-dual line. We demonstrate that, whenever dual ansätze are employed, Delta-VQE invariably detects the self-dual points rather than the true criticality. In contrast, when ansätze are carefully tailored to embody the competing phases across the boundary, the genuine Ising critical point can be successfully identified with only minor finite-size effects. Our results establish that, while Delta-VQE provides a resource-efficient probe of
quantum criticality without requiring precise ground-state preparation, its diagnostic power is fundamentally contingent upon the judicious selection of physically representative ansätze.
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Earth and Planetary Astrophysics
GRaTer-JAX: An Accelerated Package for Debris Disk Modeling
Mihir Kondapalli, Briley L. Lewis, Jaren N. Ashcraft et al. (+1 more)
GRaTer-JAX is a Python package for modeling debris disks, disks of
dust around
stars that pro- vide important clues about the formation, structure, and
evolution of planetary systems. GRaTer (Generator of Ring-like, axisymmetric, optically Thin
dust disks for regularized fitting) is a debris disk modeling framework originally developed for generating and fitting models of optically thin, ax- isymmetric
dust disks. JAX is a Python package for high-performance computing that implements just-in-time compilation and auto-differentiation, enabling significant speedups in forward modeling workflows. GRaTer-JAX delivers a more powerful, efficient, and robust debris disk modeling framework than previous tools. Its JAX-based backend provides orders-of-magnitude speedups and analytic gradients, while its intuitive and extensible API unifies forward modeling, optimization, and inference within a single workflow. Combined with key additions to its disk model, it is capable of more advanced debris disk modeling, enabling research that was previously computationally impractical such as explorations of additional morphological parameters and disk composition via scattering phase functions.
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All authors Mihir Kondapalli, Briley L. Lewis, Jaren N. Ashcraft, Maxwell A. Millar-Blanchaer
Quantum Physics
Remote entanglement of massive oscillators via wire-mediated Coulomb interaction
Lorenzo Papa, Onur Hosten and Carlos Gonzalez-Ballestero
We propose a method to enhance Coulomb interaction between charged macroscopic mechanical oscillators by placing a conducting structure in their vicinity. We derive the effective motional dynamics of the two oscillators using macroscopic
quantum electrodynamics and show that image charges induced in the conductor fundamentally modify the range of the electrostatic interaction. For the specific case of a cylindrical wire, we predict that the coherent motional coupling changes from the free-space scaling $1/D^3$ to an asymptotic $1/(D\ln^2 D)$ dependence on the separation $D$ between the oscillators, at the cost of only negligible additional decoherence for low-frequency oscillators. We further show that, when combined with continuous position measurements, the enhanced interaction enables the generation of steady-state motional
entanglement between the oscillators over significantly larger distances than achievable in free space. For experimentally realistic milligram-scale oscillators, we predict observable
entanglement at separations of several hundred microns – more than an order of magnitude beyond free-space capabilities – with improvements approaching two orders of magnitude in future systems. These results identify conductor-assisted Coulomb interactions as a resource for
quantum control of massive objects and for the exploration of
entanglement generated by fundamental central forces.
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High Energy Physics (Phenomenology)
From Gradient Postulates to Gauge Structure: Chirality, Conserved Charges, and Constraints on Internal Symmetry
Xinqiao Li
We propose a conceptual framework in which, in the non-relativistic static limit, conservative forces arise as gradients of guidance potentials, and the charges that generate these potentials are conserved and form a Lie
algebra. We examine what constraints these postulates, together with the empirical facts of parity violation and non-Abelian weak isospin, impose on the internal
symmetry group of a gauge theory. We argue that the non-Abelian character of the gauge sector follows from the conserved-charge
algebra together with the observed non-Abelian weak isospin
algebra. The requirement that the internal group accommodate
chiral fermions constrains the admissible representations. Classical stability, charge quantization, and anomaly cancellation provide three physical consistency conditions that strongly constrain the internal group to be compact. With a minimality criterion, the Standard Model group emerges as the minimal candidate among a small set of compact anomaly-free groups with
chiral content. We explicitly identify the minimality criterion as a selective assumption rather than a derived result. We do not claim a unique derivation of the Standard Model group. We also show that the scalar guidance potential reproduces Newtonian
gravity and Coulomb's law in the non-relativistic limit, and that relativistic consistency requires its upgrade to a metric tensor and gauge vector fields. The postulates substantially constrain the space of viable gauge theories and provide a conceptual basis for treating the gauge group as a constrained rather than arbitrary input.
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Lattice Field Theory
$\mathrm{SL}(2,\mathbb{Z})$ Theta Subgroup Structure of Maxwell theory in the Lattice Villain Hamiltonian Formulation
Shoto Aoki, Yoshio Kikukawa and Toshinari Takemoto
We study the duality structure of
lattice Maxwell theory with a theta term in the
Hamiltonian Villain formulation. Reflecting the fact that odd-level Chern–Simons theory depends on a choice of
spin structure, a complete realization of the full $\mathrm{SL}(2,\mathbb{Z})$ structure would require fermionic degrees of freedom. We therefore restrict our analysis to the bosonic theory and focus on the theta subgroup generated by the $\mathcal{S}$ and $\mathcal{T}^{2}$ transformations. We construct these transformations at the operator level and show that they realize the theta subgroup structure of $\mathrm{SL}(2,\mathbb Z)$. We also extend the analysis to sectors with electric and
magnetic charges, introduced as violations of the Gauss-law constraint and the Bianchi identity, respectively. We show that the $\mathcal S$ transformation exchanges electric and
magnetic charges, while the $\mathcal T^2$ transformation realizes the Witten effect. Finally, we discuss a related non-invertible defect obtained by gauging a $\mathbb Z_N$ subgroup of the global $\mathrm{U}(1)$ $1$-form
symmetry, and show that its fusion rule reproduces the expected Tambara–Yamagami structure.
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Quantum Physics
Entanglement-based quantum key distribution with data in hollow-core fiber
Yue Luo, Sheng Liu, Yun-Ru Fan et al. (+11 more)
The coexistence of
quantum information and classical signals in a single fiber is essential for future
quantum networks that leverage the well-established optical fiber infrastructure. Although multiplexing technologies can separate
quantum and classical signals, pure silica core fibers (PSCFs) remain fundamentally limited by the high nonlinearity, which generates substantial Raman scattering and four-wave mixing noise. Hollow-core fibers (HCFs), guiding light predominantly in air, offer an attractive solution with intrinsically ultra-low nonlinearity and strongly suppressed nonlinear noise. In this work, we demonstrate the
entanglement-based key coexisting with data over an 18-km HCF link. We achieve time-encoded high-dimensional
quantum key distribution (HD-QKD) carrying 0 dBm of bidirectional received power, corresponding to a theoretical data capacity of up to 2.3 Tbps. During 24 hours of continuous operation, an average secret key rate (SKR) of 10.56 kbps is obtained. Theoretical analysis further predicts SKRs above 135 kbps over transmission distances exceeding 200 km using state-of-the-art low-loss HCFs. These results show significantly improved performance compared with PSCF-based systems and highlight the potential of HCFs for scalable
quantum-classical coexistence compatible with the architectures of established fiber-optic networks.
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All authors Yue Luo, Sheng Liu, Yun-Ru Fan, Da-Wei Ge, Zhi-Yang Liu, Hao Li, Si Shen, Zi-Chang Zhang, Hai-Zhi Song, Li-Xing You, Tao Zhou, Kai Guo, Guang-Can Guo, Qiang Zhou
Optics
Physics-Informed Neural Operator for Warm-Starting Background-Decomposed and Preconditioned PSFD: Enabling Scalable 3-D EUV Mask Simulation
Doyun Kim and Werner Gillijns
We present a physics-informed neural operator (PINO) trained with pseudo-spectral frequency-domain (PSFD) equations for electromagnetic (EM) scattering problems in EUV lithography. The
Fourier neural operator is factorized into a two-dimensional lateral ($xy$) branch and a one-dimensional axial ($z$) branch and is trained self-consistently with background decomposition. Thus, the full-vector coupling between the mask and the multilayer response is retained without invoking a finite-order Born approximation. In this way, the computational domain size is significantly reduced, thereby lowering the computational cost. The PINO is trained on approximately 16,000 mask designs from the LithoBench library sampled randomly at each training iteration without using precomputed EM field solutions. The PINO surrogate model yields predictions with a mean absolute error of about $7 \times 10^{-3}$ for the scattered intensity of held-out mask patterns relative to the reference PSFD solution. Combined with spectral damping, the PINO warm-start initialization accelerates the background-decomposed PSFD solver on finer discretizations.
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High Energy Astrophysical Phenomena
SN 2022xus: bridging the gap between Type IIP and IIL supernovae
Monalisa Dubey, Kuntal Misra, Naveen Dukiya et al. (+16 more)
We present optical photometric and spectroscopic observations of the Type~II
supernova SN~2022xus. The SN reached its peak V band magnitude of $-16.32$ mag within $\sim$7 days of explosion, followed by a plateau phase lasting $\sim$94 days with a declination rate of $\sim$1.2 mag (100 day)$^{-1}$. Early time spectra exhibit broad features that could be caused by the blending of several high-ionisation lines, likely arising from a relatively weak interaction between the SN ejecta and the surrounding circumstellar medium (CSM). Compared to typical Type~IIP SNe, SN~2022xus exhibits a smaller H$\alpha$ absorption-to-emission ratio ($a/e$), indicating a relatively small hydrogen envelope mass at the time of explosion. From nebular-phase spectroscopy and bolometric light curve modelling, the progenitor mass is estimated to be in the range of 12 – 15 M$_\odot$. The multi-band light curve modelling using REDBACK infers a similar progenitor mass, a low mass-loss rate, and a confined CSM. Although several photometric and spectroscopic characteristics place the SN within the Type~IIL population, it displays mixed properties of both Type~IIP and Type~IIL SNe and cannot be cleanly classified into either subclass. We therefore identify SN~2022xus as a transitional event between Type~IIP and Type~IIL SNe, providing further evidence for a continuum between these two classes.
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All authors Monalisa Dubey, Kuntal Misra, Naveen Dukiya, Kumar Pranshu, Raya Dastidar, K. Azalee Bostroem, Yize Dong, Joseph R. Farah, Estefania Padilla Gonzalez, Emily Hoang, D. Andrew Howell, Curtis McCully, Megan Newsome, Craig Pellegrino, Aravind Pazhayath Ravi, Nicolas Meza Retamal, Ajay Kumar Singh, Giacomo Terreran, Stefano Valenti
Cosmology and Nongalactic Astrophysics
Gravitational Waves from Superconducting Cosmic Strings
Jinyoung Jhun and Takashi Hiramatsu
We study the
evolution of superconducting
cosmic-string networks in a $U(1)_{\rm local}\times U(1)_{\rm global}$ field-theoretic model using three-dimensional
lattice field simulations in an expanding universe. The scalar field charged under $U(1)_{\rm local}$ forms
cosmic strings, while the scalar field associated with $U(1)_{\rm global}$ acts as a current carrier and condenses in their vicinity. We investigate the
evolution of the string network for several values of the coupling constant between the string-forming and current-carrier fields and estimate the gravitational-wave power spectrum sourced by the resulting superconducting
cosmic-string network. We find that the spectral shape depends on the coupling constant: as the interaction strength increases, the spectrum is suppressed on small scales. This feature may be probed by future high-frequency gravitational-wave observations.
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General Relativity and Quantum Cosmology
Extracting Energy from a Non-Kerr Rotating Spacetime with an Anomalous Quadrupole Moment via Magnetic Reconnection
Ke Wang and Xiao-Xiong Zeng
This paper investigates how to extract energy from a non-Kerr rotating spacetime with an anomalous quadrupole moment via the
magnetic reconnection mechanism. Unlike many other rotating spacetimes, this spacetime possesses closed timelike curves, and the corresponding spacetime regions must be excluded when extracting energy. After introducing the event horizon, ergosphere, and closed timelike curves of this spacetime, we deeply analyze the energy per unit enthalpy at infinity for accelerated and decelerated
plasmas, the allowed region for energy extraction, and the power and efficiency of energy extraction. The results show that energy extraction is possible for both positive and negative anomalous quadrupole moments, but a positive and small anomalous quadrupole moment corresponds to higher power and efficiency of energy extraction.
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Plasma Physics
Enhanced alpha channeling with spin-polarized fuel
J. F. Parisi, A. Diallo and J. W. S. Cook
The
nuclear spin state of deuterium-tritium (D-T) fuel sets both the D-T fusion cross section and the emission direction of the fusion-born alphas and
neutrons. We show two ways that
spin-polarized fuel (SPF) could enhance alpha channeling, the wave-mediated damping of alpha power onto fuel ions rather than electrons, which is predicted to increase fusion power significantly. First, the enhanced SPF cross section produces more alphas, and second, the perpendicular (to the
magnetic field) bias of the alphas' kinetic energy couples more efficiently to the perpendicular-resonant channeling waves. The birth anisotropy survives slowing-down and appears as a population inversion of the bulk alpha distribution over a broad region of velocity space, so resonant alphas can drive a suitably tuned channeling wave rather than damp it. Without channeling, SPF roughly doubles the fusion power density through the cross-section boost and its temperature feedback on the reactivity, a well-known result. Our velocity-space calculations find the channeling efficiency about 1.5 times higher for vector-aligned fuel than for unpolarized fuel, and channeling raises the fusion power enhancement to three or four times as the channeling efficiency improves, provided the waves do not depolarize the fuel. A transport model of an ARC-class
equilibrium with stiff critical-gradient transport gives an enhancement of 2.2, rising to 3.4 for less stiff transport and to 4.7 in the zero-dimensional model when the critical gradients rise with the hotter ions. Channeling also transports helium quickly to the divertor: at fixed pumping the core helium fraction nearly halves, and a divertor pump several times less selective for helium supports the same core helium dilution.
Spin-polarized fuel thus enhances fusion power through the anisotropic alpha distribution, beyond its increase of the reactivity.
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General Relativity and Quantum Cosmology
Parametrized beyond-Teukolsky framework in the time domain
Ciro De Simone, Sebastian H. Völkel, Kostas D. Kokkotas et al. (+1 more)
Modifications to General Relativity can significantly alter the perturbative response of black holes, leaving imprints on quasinormal-mode spectra, waveform amplitudes and phases, and late-time tails. The parametrized beyond-Teukolsky framework was introduced to capture possible deviations from Kerr dynamics, but the ringdown has so far only been explored as an
eigenvalue problem. We present the first time-domain implementation of this framework and perform (2+1)-dimensional scattering experiments with Gaussian wave packets. This approach provides the full linear
evolution of the perturbation, from the initial
prompt response through the ringdown and into the late-time regime. Using frequency-domain
eigenvalue results as
benchmarks, we find excellent agreement for low azimuthal numbers, while higher azimuthal numbers are affected by mode mixing, which limits the precision of the extracted modes. We further use the time-domain waveforms to estimate quadratic and mixed coefficients within the linearized modified-potential model, providing a diagnostic for the regime of validity of the linear approximation. Beyond mode frequencies, we show that the deformation parameters can strongly affect the ringdown amplitude and phase, with trends that can be understood from the near-horizon structure of the modified potential. We also analyze the late- time behavior, finding that near-horizon deformations leave the tail exponent unchanged but can substantially shift the onset of the power-law decay. These results demonstrate that time-domain evolutions provide a complementary and flexible framework for testing parametrized deviations from General Relativity in black-hole perturbation theory.
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All authors Ciro De Simone, Sebastian H. Völkel, Kostas D. Kokkotas, Salvatore Capozziello