Atomic Physics
Quantum Dynamics of $H_2^+$ in Orthogonal Two-Color Fields
Jinzhen Zhu
We present full-dimensional
quantum simulations of $H_2^+$ dissociative ionization driven by strong orthogonal
laser fields. We consider equal-frequency orthogonal components, which generate elliptical or circular polarization depending on their relative phase and amplitude, as well as orthogonal $800$- and $400$-nm two-color fields. These two-dimensional fields strongly modify the fragmentation dynamics. Most notably, we identify a high-energy peak in the
proton kinetic-energy-release (KER) spectrum at approximately $4-5$ eV that is absent from the corresponding single-color, linearly polarized calculations. The yield of this peak can be coherently controlled by varying the relative carrier-envelope phase of the perpendicular field component. The perpendicular field also disrupts the clear electron-
proton energy-sharing pattern observed in the main $3-3.5$ eV dissociation channel, indicating more complex multichannel dynamics. Time-dependent state projections and calculations initiated from individual excited states attribute the additional peak to
laser-induced vibrational excitation of $H_2^+$. Furthermore, the perpendicular field rotates the fragment angular distributions, causing the most probable
proton and electron emission directions to deviate substantially from the principal $z$ axis. These findings demonstrate that the spatial and temporal geometry of orthogonal
laser fields provides an additional degree of freedom for controlling ultrafast electron-
nuclear dynamics.
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General Relativity and Quantum Cosmology
Defrosting the Born-Infeld dyonic frozen star with tachyon matter: spectrum of oscillations
Ram Brustein, A.J.M. Medved and Tamar Simhon
The frozen
star is a model for the interior of an astrophysical black hole that is externally indistinguishable from the singular geometry of a Schwarzschild black hole, even though it contains no singularities nor trapped surfaces. The frozen
star corresponds to a macroscopic “BIon”, a solution of a certain type of Born-Infeld Lagrangian coupled to Einstein
gravity, which consists of rigid flux tubes sourced by an electric charge localized at its center and a uniform distribution of opposite charge along its outer surface. This configuration is a solution of the effective action that describes the end point of tachyon condensation in string. The
rigidity of the flux tubes implies that the
star is ultrastable under linear perturbations of the geometry and matter. The
star can be effectively deformed, or “defrosted”, allowing internal pulsations, as expected from regular, horizonless astrophysical black holes. To describe the defrosted
star, we need to include a perturbative amount of
magnetic-monopole charge and tachyon kinetic energy. This recasts the
star as a macroscopic “DIon”, whose flux tubes can stretch and contract, having both electric and
magnetic charges localized at its center and distributed uniformly along its outer surface. Previously, the non-radial oscillations of the defrosted
star were analyzed to leading order in a perturbative “defrosting” parameter $\gamma$, by describing the energy-momentum tensor as that of a fluid. Here, we derive the same spectrum in a much simpler way, using the Born-Infeld Lagrangian. Thus, we verify that the sound velocities scale as $\gamma$ and the parametrically long lifetimes scale as $1/\gamma^2$. Because the perturbation equations are derived from a Lagrangian, their consistency is guaranteed for arbitrary deviations away from spherical
symmetry, facilitating numerical studies on frozen
stars away from
equilibrium.
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Quantum Physics
Quantum-Enhanced Multi-Objective Optimization
Maolin Luo, Jiapei Zhuang, Zuoheng Zou et al. (+1 more)
Multi-objective combinatorial optimization requires identifying Pareto-optimal trade-off solutions among conflicting objectives, often making it more demanding than its single-objective counterpart. Although
quantum multi-objective optimization methods have begun to emerge, most existing
quantum optimization workflows are still built around single-objective or fixed-scalarization settings. Building on existing weighted-sum QAOA approaches to
quantum multi-objective optimization, we propose QEMOO, a
quantum-enhanced multi-objective optimization framework that combines Pareto-based selection and warm-started QAOA sampling in a multi-round protocol under the same total shot budget. We further introduce a PBI-inspired adaptive direction-update scheme to improve coverage in strongly conflicting
benchmark regimes. Across three
benchmark stages, QEMOO improves Pareto-front hypervolume over the single-pass weighted-sum QAOA baseline under matched shot budgets, suggesting a practical route toward shot-efficient
quantum-assisted multi-objective optimization and its future applications.
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All authors Maolin Luo, Jiapei Zhuang, Zuoheng Zou, Man-Hong Yung
High Energy Physics (Phenomenology)
Probing the vector-like $X$ quark via the $tW$ channel at future muon-proton colliders
Liangliang Shang, Shuting Zhao, Bingfang Yang et al. (+1 more)
We investigate the discovery potential for the vector-like $X$-
quark (VLX) at future
muon–
proton ($\mu p$)
colliders through the process $\mu^+ p \to \bar{\nu}_\mu X \to \bar{\nu}_\mu t W^+$. A simplified effective model is adopted in which the production and decay of the VLX are governed by the coupling strength $g^{*}$, the generation-mixing parameter $R_{L}$, and the VLX mass $m_X$. A comprehensive Monte Carlo analysis is performed at $\sqrt{s}=5.29$, $6.48$, and $9.16\ \mathrm{TeV}$, considering four complementary decay channels: the Fully Leptonic (FL), Fully Hadronic (FH), and two Semi-Leptonic (SL1 and SL2) modes. An $80\%$ polarized
muon beam together with boosted-object reconstruction based on fat-jet techniques is employed to improve the signal sensitivity. The expected exclusion and discovery reaches are evaluated using the Asimov significance. We find that the sensitivity can be improved substantially with increasing center-of-mass energy and larger values of $R_L$. Among the four channels, the FH mode provides the strongest sensitivity, reaching a $2\sigma$ exclusion limit of $m_X\simeq8.3\ \mathrm{TeV}$ with $g^* = 0.009 $ for $R_L=0.1$ at $\sqrt{s}=9.16\ \mathrm{TeV}$, whereas the FL mode gives the weakest reach because of its smallest branch ratio. These results demonstrate that future $\mu p$
colliders can offer significant sensitivity to heavy VLX over a broad region of parameter space.
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All authors Liangliang Shang, Shuting Zhao, Bingfang Yang, Stefano Moretti
Mathematical Physics
Torsionful Killing-Yano Forms under T-Duality: Transformation Conditions and Emergent Isometries
Özgür Kelekçi, Ümit Ertem and Özgür Aç{\i}k
We investigate the transformation of Killing-Yano (KY) $p$-forms under Abelian T-duality in the presence of a non-trivial three-form torsion. Using a torsionful, metric-compatible connection and the Buscher rules of T-duality, we derive compact, coordinate-free transformation laws applicable to KY forms of arbitrary degree under explicit matching assumptions. In particular, we show that a Killing 1-form is preserved by the direct duality map whenever its transverse components are independent of the isometry direction, with the dual circle component determined by a scalar correction equation. The framework is then applied to several examples, including the
Hopf T-dual of $S^3$, Schwarzschild spacetime, and the Nappi-Witten plane wave with exact NS-NS torsion, where we analyze the transformed Killing-Yano forms explicitly. Finally, we give a generalized-
geometric and double-field-theoretic interpretation of emergent Killing 1-forms in the T-dual geometry, showing how they arise from generalized Killing data in the original duality frame.
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Plasma Physics
Quantitative schlieren imaging coupled with inverse Abel transformation for flow field studies in a cylindrical surface DBD
K Giotis, A G Makrypodi, P Svarnas et al. (+2 more)
The present work is devoted to the proper application of the schlieren imaging technique, combined with inverse Abel transformation, to record the flow field induced by atmospheric pressure cold
plasmas, in a quantitative manner. Theoretical principles, along with meaningful diagrams, design of the schlieren setup, and involved calibration process, are given in detail. It is demonstrated that erroneous conclusions may be reached if Abel transformation is omitted. The concept is employed to study flow field parameters around a surface dielectric barrier discharge, operating in ambient air and having a cylindrical configuration, rather than a typical planar design. Maximum density and lowest temperature equal to 1.24 kg m -3 and 285.4 K, respectively, and lowest density and maximum temperature equal to 1.11 kg m -3 and 318.8 K, respectively, downstream of the driven electrode and close to the surface are identified with respect to the unperturbed air where density equals 1.21 kg m -3 and temperature equals 291.5 $K$. The temperature and density patterns unveil intense perturbations at shorter distances from the surface and lower amplitudes of the sinusoidal (10 kHz) voltage that sustains the discharge. Electrohydrodynamic effects seem to dominate over thermal mechanisms in governing the flow field. The importance of the quantitative schlieren technique, as a non-invasive one, in the study of dielectric barrier discharges is justified by the interest that they attract in numerous demanding cases of
plasma-assisted flow field control (propulsion, actuators, etc.).
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All authors K Giotis, A G Makrypodi, P Svarnas, K Gazeli, G Lombardi
Mathematical Physics
Towards General Relativity as a generalized Yang-Mills theory
Hartwig Winterroth and Lorenzo Fatibene
As an application of the generalized principal bundle theory to covariant Lagrangian field theories, we aim at the development of an instance of generalized gauge theories, with the prospect of a unifying
language for Yang-Mills theories and General Relativity. After reviewing the basic definitions of Lie group fiber bundles and generalized principal bundles, we provide horizontal lift and local characterizations of Lie group fiber bundle connections and generalized principal connections. Subsequently, we consider in the framework of classical field theories the kinematics and dynamics sides of generalized principal connections, which lead to a proposed notion of generalized Yang-Mills theories. Finally, we show how vector bundles are examples of generalized principal bundles and that a generalized principal connection on a vector bundle is an affine connection given in terms of basic soldering forms. We are able to recover, under appropriate assumptions, the Vielbein formulation of (
vacuum) General Relativity in this setting, hinting at a (generalized) gauge theory of
gravity.
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High Energy Physics (Phenomenology)
Automated higher-order predictions for ultra-peripheral collisions with full impact-parameter dependence
Frank Krauss and Peter Meinzinger
We present an automated framework within the Sherpa event generator for the simulation of
photon-induced processes in high-energy collisions of
protons and
nuclei. The calculation builds upon the equivalent-
photon approximation and incorporates different form factor parametrisations, taking into account the full dependence on the finite size of emitters and their impact parameter. Higher-order effects are taken into account automatically by either YFS-resummation of soft
photon emissions to all orders or Next-to-Leading Order in electroweak theory. We validate our simulation framework using data from two representative ATLAS measurements of exclusive $\mu$-pair production in $pp$ and Pb+Pb collisions. Exemplary predictions for exclusive $W$-pair production in $pp$ collisions and $\tau$-pair production in both $pp$ and Pb+Pb collisions are presented.
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High Energy Physics (Phenomenology)
Chromoelectric and chromomagnetic quarkonium couplings to scalar and spin-two nucleon structure
Arkadiy I. Syamtomov
The chromoelectric and chromomagnetic polarizabilities of compact heavy quarkonium weight the scalar and
spin-two structure of the nucleon differently. We derive the corresponding finite-momentum-transfer elastic response kernels, retaining the physical quarkonium velocity and nucleon
spin dependence. Their correlated uncertainties are determined using
lattice quark and
gluon gravitational form factors. For $\Upsilon(1S)N$ at $100\,\mathrm{MeV}$ above threshold and $Q^2=0.20\,\mathrm{GeV}^2$, the electric non-
spin-flip kernel is $1.316\pm0.100_{\rm GFF}\,\mathrm{GeV}$. The electric and
magnetic kernels exhibit distinct momentum-transfer and
spin dependence. These kernels describe the nucleon response to the local operators. Their contributions to elastic scattering are weighted by the independent quarkonium polarizabilities.
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Mathematical Physics · Cross-listed from cs.LG
Countercurrent Multiplier Networks: A Renal-Inspired Iterative Operator with Provably Bounded Fixed-Point Dynamics
Snigdha Chandan Khilar
The mammalian kidney concentrates urine using a mechanism with no analogue in current neural architectures: the countercurrent multiplier. Two anti-parallel flows joined at a hairpin recirculate a weak magnitude-bounded local pump into a large axial gradient achieving a four-fold concentration increase from a single-effect gradient that never exceeds 200 mOsm at any point. We formalize this mechanism as a differentiable sequence operator the Countercurrent Multiplier (CCM) layer and study it as an alternative to residual iterative refinement.
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Mathematical Physics · Cross-listed from math.PR
Non-Abelian multiplicative chaos on the circle
Guillaume Baverez
In this note, we introduce a generalisation of multiplicative chaos measures which is both non-Gaussian and non-Abelian. The renormalisation procedure takes as inputs an irreducible
unitary representation of a compact connected Lie group, together with a Kac-Moody unitarising measure at some level $\kappa$, and outputs a random measure on the circle with values in the space of positive definite Hermitian endomorphisms of the representation space. So far, our construction is valid for the range of $\kappa$-values corresponding to the $L^2$-phase. The proof follows the usual route in the theory of multiplicative chaos, relying on an exact formula for the one-point function and a bound on the two-point function at colliding points. These expressions are derived using the rich algebraic structure of the theory: namely, we establish a one-dimensional version of the Knizhnik-Zamolodchikov equations.
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Classical Physics
Three-Dimensional Bubbly Flow Measurement Using Event-based Vision Sensor Cameras
A Al Brahim, K Rajamanickam, B Lecordier et al. (+2 more)
A three-camera Event-Based
Vision Sensor (EVS) system is employed to perform three-dimensional measurements of bubble motion, morphology, and bubble{\DH}bubble interactions. The multi-EVS configuration mitigates the absence of direct depth information inherent to binary event-based imaging while preserving key advantages, including high temporal resolution, low latency, and reduced data throughput. The experimental configuration consisted of an octagonal tank equipped with a controlled particle release mechanism and an air diffuser. Camera synchronization and pulsed LED illumination were achieved using a dedicated signal generator and driver circuitry, while calibration was performed using pulsed-illumination recordings of a target acquired at multiple depths. A comprehensive, inhouse computational framework was developed to process the event data for three-dimensional motion trajectory reconstruction. The validation of the developed tracking framework followed a rigorous multi-stage pipeline to ensure reconstruction fidelity. The framework was initially benchmarked against synthetic rendering cases of increasing kinematic complexity to evaluate 3D trajectory reconstruction accuracy under controlled conditions, achieving sub-millimeter global accuracy with root-mean-square error (RMSE) values ranging from 0.015 to 0.36 mm. Following numerical validation, physical baseline experiments were conducted using precisely manufactured particle releases through both a gated chamber and a single-particle claw opening mechanism. Subsequently, dynamic bubble plumes generated via multiple inlets across various compressed air flow rates were evaluated. The EVS framework successfully resolved dense bubble-bubble interactions, producing smooth, physically consistent three-dimensional trajectories across all tested conditions. Quantitative results showed strong agreement, yielding an overall velocity consistency exceeding 97% between conventional centroid tracking and independent velocity estimates derived from continuous-illumination event streaks. Overall, this methodology demonstrates a robust framework for high-speed volumetric tracking and bubble flow measurement. However, event oversaturation remains a key hardware limitation in ultra-dense regimes, as oversaturation in a single camera can cause system desynchronization.
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All authors A Al Brahim, K Rajamanickam, B Lecordier, A Taylor, Y Hardalupas
Optics
Wave chirality reversal without passing achirality
M. V. Berry, K. Y. Bliokh and J. M. Robbins
Chiral connectedness describes
chiral structures that transform smoothly into their mirror images while never being achiral. The phenomenon is illustrated with a two-parameter family of complex vector fields E representing paraxial optical Gaussian beams. E is
chiral everywhere in the parameter plane except the origin. During a
circuit of the origin, E reverses chirality twice without being achiral. Different aspects of chirality are associated with the vector and scalar nature of E; natural measures of each, and their combinations, change sign at parameter values where E is
chiral. The analysis is simpler for planar fields E, but their chiralities are essentially the same when the subtleties of three dimensions are included.
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Superconductivity
Collective modes in non-Hermitian fermionic superfluids
Gabriel Angelo V. Vila and Kristian Hauser Villegas
The
Higgs and Nambu-Goldstone modes are paradigmatic collective excitations in
superconductors and superfluids. These modes are commonly analyzed within the pseudospin formulation of BCS theory, where the dynamics are obtained from the Heisenberg equations of motion for pseudospins. However, this construction becomes inconsistent when directly extended to non-Hermitian systems. In this work, we develop a consistent pseudospin framework for non-Hermitian fermionic superfluids based on the metricized formulation of non-Hermitian
quantum mechanics. We apply this formalism to a driven non-Hermitian BCS-type
Hamiltonian with complex pairing interaction and analyze its collective excitation spectrum. We find that, in addition to the conventional
Higgs (amplitude) mode, the system hosts a novel phase mode that has no counterpart in Hermitian superfluids. Remarkably, this mode is gapped even in the absence of the Anderson-
Higgs mechanism, as is the case in neutral superfluids. Furthermore, the resonance spectrum depends explicitly on the initial nongauge phase of the complex order parameter and the dynamical response remains finite at resonance, in contrast to the divergence characteristic of Hermitian systems. These resonances disappear upon the emergence of exceptional points.
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General Relativity and Quantum Cosmology
Tidal Deformability of Neutron Stars in Bumblebee Gravity: Probing Lorentz Symmetry Breaking with Gravitational Waves
Ayan Banerjee, sherzod Sayfiyev, Muhtarama Radjapbaeva et al. (+3 more)
We investigate the
tidal properties of static
neutron stars in the Neves–Gardim branch of bumblebee
gravity, a vector–tensor theory in which a nonzero
vacuum expectation value of the bumblebee field spontaneously breaks local Lorentz
symmetry. The
stellar background is determined from the full modified Tolman–Oppenheimer–Volkoff system, including the term containing $m''(r)$. For a differentiable barotropic equation of state, this system is recast into an algebraically equivalent first-order form without discarding any bumblebee-dependent contribution. Because a complete coupled derivation of static even-parity metric and bumblebee-field perturbations is not presently available for this
stellar branch, the
tidal sector is treated through an explicit effective metric-deformation prescription: the Hinderer fluid perturbation equation is evaluated on the modified bumblebee background, and the standard surface matching relation is retained as part of the same prescription. We compute the quadrupolar
tidal Love number $k_2$ and the dimensionless
tidal deformability $\Lambda=(2/3)k_2\mathcal{C}^{-5}$ for the BSk20, BSk21, DD2, and MS1 equations of state over $\ell\in[-0.4,+1.0]$. The general-relativistic limit is recovered at $\ell=0$ to within $0.2\%$ in the
benchmark calculations. Within the adopted effective prescription, comparison with the GW170817 binary
tidal-deformability bound $\widetilde{\Lambda}\leq720$ yields the EOS-dependent limiting values $\ell_{\max}=+0.25$ (BSk20), $+0.06$ (BSk21), $-0.09$ (DD2), and $-0.25$ (MS1). These
tidal limits are conditional on the stated perturbative prescription and should be reassessed when the complete linearised vector–tensor problem becomes available.
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All authors Ayan Banerjee, sherzod Sayfiyev, Muhtarama Radjapbaeva, Javlon Rayimbaev, Shokhzod Jumaniyozov, Aseel Smerat
Solar and Stellar Astrophysics
KIC 6464285: A Solar-type Eclipsing Binary in a Hierarchical Triple System with Quasi-periodic Out-of-eclipse Modulations
Fang-Bin Meng, Li-Ying Zhu, Sheng-Bang Qian et al. (+10 more)
We present the first detailed analysis of the
solar-type triple system KIC 6464285. Combining long-term, high-precision photometry from Kepler, TESS, and ZTF with low-resolution spectra from LAMOST and near-infrared high-resolution spectra from SDSS/APOGEE, we performed a joint analysis of the light curves, eclipse timing variations (ETVs), and radial velocities. Spectroscopic analysis reveals the system to be triple-lined, with the inner binary's primary being a G-type main-sequence
star and a mass ratio of $0.627(7)$. Light curve modeling indicates that the inner binary is detached, with filling factors of approximately 26% and 11% for the primary and secondary, respectively, and a tertiary light contribution of about 27%. ETV analysis shows a significant light-travel-time effect (LTTE), consistent with the presence of the tertiary companion, whose minimum mass is estimated as $M_{3,\rm min}=0.74(1)~M_\odot$. The light curve exhibits a pronounced O'Connell effect and quasi-periodic variations, indicative of starspot activity modulating the photometry on a $\sim$131-day timescale. Kepler observations further reveal 30 superflares, each with total energies exceeding $10^{34}$ erg. This study presents detailed observational constraints on the orbital configuration,
stellar properties, and
magnetic activity of KIC 6464285, providing a
benchmark for studies of hierarchical triple systems.
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All authors Fang-Bin Meng, Li-Ying Zhu, Sheng-Bang Qian, Ildar Asfandiyarov, Azizbek Matekov, Jaqsiliq Baltamuratov, Wen-Ping Liao, A-Li Luo, Wen Hou, Ping Li, Lin-Jia Li, Er-Gang Zhao, Jia-Jia He
High Energy Astrophysical Phenomena
Searching for $\gamma$-ray emission from a bona fide Compact Symmetric Object sample: a $\gamma$-ray signal near GB6 J0906+4124
Ying-Ying Gan, Kai Wang, Ji-Shun Lian et al. (+1 more)
As a particular subclass of active
galactic nuclei (AGNs), compact symmetric objects (CSOs) have attracted significant
attention due to potential role as young AGNs. Several $\gamma$-ray emitting CSOs have been detected with
Fermi Large Area
Telescope (
Fermi-LAT), which motivates further searches for more $\gamma$-ray emitting CSOs. We perform a systematic search for $\gamma$-ray emission from a bona fide CSO sample using 16 yr
Fermi-LAT observation data. No significant $\gamma$-ray signal is found to be firmly associated with any CSO. Only one $\gamma$-ray signal is detected near CSO GB6 J0906+4124 with TS = 28.7 ($\sim4.9\sigma$) in 0.1–300 GeV band. Within the 68% containment radius of
Fermi-LAT average PSF at 3 GeV, GB6 J0906+4124 remains the plausible counterpart of the $\gamma$-ray signal, primarily due to its classification and broad spectral coverage. This work suggests that GeV emission from CSOs may either be uncommon or simply below the current
Fermi-LAT detection sensitivity. Further multi-wavelength follow-up is needed to determine the origin of the $\gamma$-ray signal near GB6 J0906+4124.
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All authors Ying-Ying Gan, Kai Wang, Ji-Shun Lian, Run-Meng Wang
Statistical Mechanics · Cross-listed from q-bio.PE
Ecological networks of viable species with degree-dependent interaction
Hae Seong Lee, Deok-Sun Lee, Sang Hoon Lee et al. (+2 more)
The generalized Lotka-Volterra (GLV) framework, recently advanced by dynamical mean-field theory, enables the systematic analysis of large ecological networks. When combined with structured interaction
topologies, previous studies have shown that the viability of species, defined by having a positive stationary abundance, depends on the number of their interacting neighbors or the "degree." While such model studies usually assume that interaction strengths follow an identical distribution across all connected pairs, real ecological communities often exhibit correlations between interaction strength and a species' degree. To capture this overlooked feature, we introduce degree-dependent interaction strengths into a generalized random LV model. We identify two distinct regimes: a hub-favored phase, where highly connected species survive preferentially, and a hub-suppressed phase, where they face higher extinction risks. We analytically derive the phase boundary where these degree-dependent strengths precisely balance the connectivity effect, leaving all species equally susceptible. Crucially, these phases induce opposing shifts in the degree-degree correlation or "assortativity" of the network of viable species: the hub-favored phase enhances disassortativity by selectively removing the interactions between low-degree species, whereas the hub-suppressed phase reduces it as the interactions involving hub species tend to disappear. Ultimately, our findings demonstrate that degree-dependent interactions are a fundamental mechanism not only for shaping species survival, but for naturally reproducing the wide range of assortativity values observed in real ecological networks.
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All authors Hae Seong Lee, Deok-Sun Lee, Sang Hoon Lee, Samir Suweis, Hye Jin Park
Atomic Physics
In Situ Coherence Measurements of Scattered Light in Magnetically Trapped Cold Atomic Clouds: Probe-Driven Atomic Dynamics
Amilson R. Fritsch, Hector Letellier, Leonardo Lima da Silva et al. (+4 more)
The use of temporal correlations in scattered
photons to probe the microscopic dynamics of ultracold
quantum gases has emerged as a powerful, minimally destructive approach for in situ analysis. Here, we demonstrate that temporal coherence spectroscopy can quantitatively characterize atomic motion in a
magnetic trap, despite the perturbative effects of the probing light. By measuring the first-order correlation function g (1) ($\tau$ ) of light scattered by a 87 Rb cloud confined in a quadrupole trap, we identify radiation-pressure-induced acceleration and heating as the origin of the apparent discrepancy between coherence spectra and temperatures inferred from time-of-flight measurements. A simple dynamical model incorporating these effects restores agreement between theory and experiment, establishing coherence spectroscopy as a reliable in situ probe of velocity distributions in trapped atomic ensembles. Our results pave the way for time-resolved studies of nonequilibrium dynamics and thermalization processes in confined cold gases, complementing conventional destructive imaging techniques.
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All authors Amilson R. Fritsch, Hector Letellier, Leonardo Lima da Silva, Pierre Azam, Vanderlei Salvador Bagnato, Robin Kaiser, Mathilde Hugbart
Mesoscale and Nanoscale Physics
Double anticrossings induced by nonlinear magnon interactions
Geil Emdi, Tomosato Hioki, Koujiro Hoshi et al. (+3 more)
We observe pump-induced double anticrossings whose gap sizes and center-frequency shifts depend strongly on pump power, indicating a nonlinear mechanism. The anticrossings vanish at high
magnetic fields, where energy conservation suppresses three-
magnon splitting, thereby identifying the underlying process as three-
magnon scattering. We attribute the double anticrossings to nondegenerate three-
magnon splitting, which generates two
magnon populations at distinct frequencies. Each population forms a standing-wave mode and couples independently to the Kittel mode, giving rise to two effective coupling channels. These results demonstrate that nonlinear
magnon interactions can dynamically generate multiple coupling channels within a single system.
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All authors Geil Emdi, Tomosato Hioki, Koujiro Hoshi, Takahiko Makiuchi, Aoi Yamauchi, Eiji Saitoh
Quantum Physics
Simulating Majorana fermions in black hole with Ising Models
John Vienn A. Estremadura and Kristian Hauser A. Villegas
Quantum field theory (QFT) in curved spacetime has led to profound predictions, including the Unruh effect and Hawking radiation, yet their direct observation remains extraordinarily challenging because of their extremely weak signatures. Here, we show that the transverse-field Ising model provides a
quantum simulator for Majorana
fermions in a Schwarzschild black hole background. Remarkably, different coordinate representations of the same spacetime-Schwarzschild, tortoise, Kruskal, and conformally flat-map onto distinct microscopic Ising
spin models. Despite their microscopic differences, these models converge in the continuum limit to the same Majorana field theory, exhibiting an emergent form of general covariance. This provides a rare example of a fundamental
symmetry of general relativity arising as an emergent property of a condensed matter system. We further demonstrate how black hole particle production can be simulated and detected through
spin correlation measurements, and discuss experimental platforms capable of realizing these models. Our work establishes a practical route for investigating fermionic QFT in curved spacetime using controllable
quantum many-body systems and tabletop experiments.
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High Energy Physics (Phenomenology)
A Non-Holomorphic Modular $A_4$ Framework for Resonant Leptogenesis with Gravitational Wave Signatures
Mitesh Kumar Behera, Jaydeb Das and Niloy Mondal
We study a type-I seesaw framework based on non-holomorphic $A_4$ modular
symmetry, where polyharmonic Maaß\ forms construct the Yukawa couplings and right-handed
neutrino (RHN) Majorana mass
matrix. The use of non-holomorphic modular forms yields highly constrained neutral
lepton mass
matrices with a more restrictive
lepton-sector structure and naturally generates a quasi-degenerate RHN mass spectrum, enabling resonant leptogenesis at an intermediate scale with RHN masses of $\mathcal{O}(10^3)$ TeV without requiring an ad hoc mass degeneracy. We further extend the model by introducing a complex scalar field $(\Phi)$ charged under $\mathbb{Z}_3$
symmetry. The spontaneous breaking of the discrete
symmetry after the phase transition associated with $\Phi$ leads to domain-wall (DW) formation. A radiatively induced bias term associated with the RHN sector triggers DW annihilation, resolving the cosmological DW problem, and producing a
stochastic gravitational wave (GW) signal that indirectly probes the RHN mass scale. The accompanying first-order phase transition produces a second GW peak, yielding a characteristic double-peaked spectrum with frequencies separated by several orders of magnitude and potentially observable by complementary future GW detectors.
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High Energy Physics (Phenomenology)
Domain Walls From Confining Bubbles: $SU(N_{c})$ Yang Mills at Finite $\theta$
Bruno Missoni, Enrico Morgante and Nicklas Ramberg
We study the confinement phase transition in SU($N_{c}$) pure Yang-Mills theory at finite $\theta \neq 0$ using the Improved
Holographic QCD (IHQCD) model. We show that the critical temperature, as a function of $\theta$ for large but fixed $N_{c}$, is reduced, thus decreasing the amount of supercooling in the confinement phase transition. Upon completion of the confinement phase transition, a network of domain walls can be produced, owing to the multi-branched
vacuum structure of Yang-Mills theory at finite $\theta$. We highlight the potential interplay between the produced domain walls and the confinement phase transition dynamics. We emphasize that DW production from bubble coalescence in strongly coupled non-conformal FOPTs is a dynamical process of
vacuum assignment, hydrodynamics, and local reheating effects, all potentially affecting the approach towards the scaling regime. Lastly, we demonstrate the level of tuning necessary for potentially interesting imprints from gravitational waves through domain wall annihilation and its interplay with the confinement PT.
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Quantum Physics
Quantum Sensing Beyond Exceptional Points via Hidden symmetry-protected vacuum-noise fixed point
Wencong Wang, Yuyang Liang, Peng Han et al. (+3 more)
Exceptional-point (EP) sensing has attracted considerable interest because of its anomalous response scaling. However, recent studies have shown that the enhanced response near an EP is inevitably accompanied by amplified
quantum noise, fundamentally limiting the achievable signalto-noise ratio (SNR). Here, we propose a fundamentally different route toward non-Hermitian
quantum sensing based on
symmetry-protected noise suppression rather than response amplification. We develop a fully
quantum continuous-variable model that unifies parity-time (PT) and anti-paritytime(APT)
symmetries within a single framework. Exploiting the incompatibility between these two
symmetries, we uncover a non-Hermitian Dirac eigenspectrum and reveal a hidden symmetryprotected phase transition embedded in the
Hamiltonian spectrum. Remarkably, this hidden phasetransition simultaneously constitutes a
symmetry-protected
vacuum-noise fixed point, where collective three-mode quadratures exhibit suppressed
quantum fluctuations despite the absence of any anomalous spectral response. As a consequence,
quantum sensing is enhanced through the suppression of excess
quantum noise while maintaining a finite response sensitivity, establishing a sensing mechanism fundamentally different from conventional EP-based approaches. These results reveal an unexpected connection between hidden
symmetry,
quantum fluctuations, and non-Hermitian
quantum metrology, and establish noise suppression as an alternative paradigm for non-Hermitian
quantum sensing.
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All authors Wencong Wang, Yuyang Liang, Peng Han, Xianqiu Wu, Dongmei Liu, Min Gu
Instrumentation and Detectors
A method for energy and radius reconstruction with simulated charge information in a ton-scale liquid scintillator detector like Taishan Antineutrino Observatory
Randhir Singh, Yichen Li and Xiaochuan Xie
Small
neutrino detectors are a ton level detectors which can be placed very close to the core of
Nuclear Power Plant. In some detectors
liquid scintilling (LS) material is used as the detecting material. The antineutrinos from the reactor core fall on the
liquid scintillator of the detector where they deposit energy via Inverse Beta Decay process (IBD). The energy absorbed by
liquid scintillator is re-emitted in the form of scintillation. These
photons then travel through the scintillating material and hit the Silicon Photo Multipliers (SiPMs) which are installed on the inner surface of detector's spherical copper shell. These SiPMs absorb the
photons to give a charge output signal. The energy and radius reconstruction is done using the information of charge collected by the SiPMs. Due to factors like large photo-coverage with large
photon detection efficiency, small spherical detector size and low temperature operation, small size LS detectors can achieve an unprecedented energy resolution. In this paper, we have used a template-dependent method exploiting simulated data to reconstruct the event radius and energy. This method uses response functions generated using radioactive source calibration data and the charge information to reconstruct the energy and the radius of the event by constructing maximizing a likelihood function. This methodology is applicable to all similar size spherical
neutrino detector experiments.
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Fluid Dynamics
Wave collapse proliferation as a mechanism for anomalous dissipation and spontaneous stochasticity
Wandrille Ruffenach
Anomalous dissipation and spontaneous stochasticity are signatures of the roughness of the inviscid limit in fluid
turbulence. Spontaneous stochasticity describes the selection of a probability distribution over possible solutions rather than a single deterministic trajectory. We investigate these phenomena in a nonlinear dispersive equation undergoing finite-time blowup, known as wave collapse. Collapse is arrested by two regularization mechanisms, one dissipative and one conservative. Heuristic arguments supported by numerical simulations show that an isolated collapse has a vanishing effect in the inviscid limit and cannot alone account for either phenomenon. However, simulations reveal that the number of collapse events diverges as the regularization vanishes. Their proliferation enables sustained dissipation in the dissipative case and prevents either regularization from selecting a single inviscid solution. We then introduce vanishingly small random perturbations and find numerical evidence for a well-defined statistical limit in which randomness persists. These results identify collapse proliferation as a mechanism connecting anomalous dissipation and spontaneous stochasticity in dispersive waves, allowing a formally deterministic equation to acquire a truly random limiting
evolution.
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Mathematical Physics
Tau functions and correlation functions of the bosonic universal character hierarchy
Denghui Li, Jinzhou Liu and Zhaowen Yan
This paper is concerned with the construction of the bosonic universal character (UC) hierarchy, whose tau functions are investigated within the framework of charged free
bosons. The Lie
algebra corresponding to the bosonic UC hierarchy is $\mathfrak{\widehat{gl}}_{2\infty}$. It is shown that the tau functions of bosonic UC hierarchy can be represented based on a series of ordered exponential operators. Furthermore, we derive correlation functions of the bosonic UC hierarchy, which can be expressed as the product of UCs. It is worth noting that the correlation functions of the bosonic UC hierarchy are the inverse of the correlation functions of the generalized phase model.
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Instrumentation and Methods for Astrophysics
Enhanced Astrometry of the Rapid ASKAP Continuum Survey: Mid and High Frequency Epochs
Akhil Jaini, Adam T. Deller, Yuanming Wang et al. (+3 more)
Accurate
radio astrometry is essential for reliable cross-identification of sources across wavelengths, precision localisation of transient events, and the construction of stable all-sky reference catalogues. In this work we extend our astrometric correction framework for the Rapid ASKAP Continuum Survey (RACS) to its mid- and high-frequency epochs (RACS-Mid1 and RACS-High1), building on our previous corrections to the low-frequency surveys. Using a hierarchical crossmatching strategy with high-precision external catalogues, we remove large-scale systematic positional errors that were present in the uncorrected data and significantly reduce the residual scatter across the sky. After correction, the median positional offsets are effectively eliminated, and the 68% confidence interval of the mean residuals of RACS source positions averaged over $~\sim1$~sq. deg. regions is reduced from $\gtrsim 0.4''$ to $\lesssim 0.18''$ over most of the survey area for both epochs. Independent validation against multiple external
radio astrometric references confirms that individual corrected RACS source positions are accurate to a 1-$\sigma$ confidence level of $\sim 0.25''$ across the bulk of the sky, with slightly degraded performance within the
Galactic plane. While motivated primarily by the need for improved localisation of ASKAP fast
radio bursts, these corrections also benefit a wide range of science applications, including transient identification, multiwavelength host association, and studies of
Galactic and extragalactic
radio populations. Together with our previous work, this establishes RACS as the highest precision arcsecond-resolution all-sky astrometric reference in the southern hemisphere at decimetre wavelengths.
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All authors Akhil Jaini, Adam T. Deller, Yuanming Wang, Emil Lenc, Stefan W. Duchesne, Marcin Glowacki
Chaotic Dynamics
Statistical periodicity in noise-induced order from Ruelle-Pollicott resonances
Yuzuru Sato and Isaia Nisoli
Noise-induced order (NIO) is a paradigmatic example of nontrivial noise-induced phenomena, characterized by pronounced spectral peaks and pseudoperiodic dynamics. We show that this periodicity is governed by the Ruelle-Pollicott resonances of the annealed transfer operator, independently of dynamical stability. Exact results for an analytically solvable model and numerical results for a modified Lasota–Mackey map show excellent agreement between resonance-based predictions and empirical power spectra across a broad range of noise amplitudes. Independent transitions in stability, diagnosed by the Lyapunov exponent, and statistical periodicity, diagnosed by the Ruelle-Pollicott resonances, give rise to three distinct types of NIO.
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Mesoscale and Nanoscale Physics
Magnetoconductivity of two-dimensional Dirac cones and gapped nodal-rings under impurity-potentials in the ultraquantum limit
Ipsita Mandal and Sanskar Sharma
We investigate the dc magnetoconductivity of two-dimensional Dirac cones and gapped nodal rings (GNRs) subjected to a perpendicular
magnetic field, which quantises the electronic spectrum into Landau levels (LLs). Working in the ultraquantum limit, where only the lowest LL (LLL) is partially occupied, we employ the Kubo–Bastin formalism to compute the transport coefficients for pointlike, Gaussian, and Yukawa
impurity-potentials. For the Dirac case, the longitudinal conductivity is field-independent for pointlike
impurities and a monotonic function of $B$ for the Gaussian and Yukawa potentials, while the
Hall conductivity vanishes identically owing to the particle-hole
symmetry of the two neighbouring LLs. The GNR case is qualitatively different: its non-monotonic stretched-checkmark LL spectrum causes the effective LLL to migrate to successively lower indices as the field increases, producing a pronounced oscillatory structure in both conductivities. The longitudinal response develops resonant peaks at LLL degeneracies, while the
Hall conductivity traces out a sawtooth pattern with sharp zero-crossings at these same points. These results establish distinct transport fingerprints for the two systems in the extreme
quantum limit, and provide a theoretical framework for interpreting magnetotransport experiments on GNRs.
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