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2512.09512 2026-04-23 astro-ph.CO

SLICE -- Combining Strong Lensing and X-ray in AC 114. Further Insights into the Merger Scenario

Marceau Limousin, Benjamin Beauchesne, Keren Sharon, Dominique Eckert, Guillaume Mahler, Johan Richard, David Lagattuta, Gourav Khullar, Mathilde Jauzac, Mike Gladders, Marco Balboni, Fabio Gastaldello, Stefano Ettori, Catherine Cerny, Eric Jullo, Gavin Leroy, Nency Patel

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AC114 is a historically significant galaxy cluster, being one of the first strong lensing clusters detected from the ground in the early 1990s, prior to the launch of the HST. Despite this early prominence, no detailed lensing analyses have been carried out for more than fifteen years. We here study this cluster using JWST imaging obtained as part of the SLICE program, complemented by archival HST and X-ray observations. JWST data reveal ten new multiply imaged systems and enable the identification of conjugate substructures in several of the sixteen systems, significantly increasing the number of strong lensing constraints. Using these data, we construct a parametric mass model with Lenstool and extend it by explicitly incorporating the Chandra data in a combined strong lensing+X-ray fit. Our best-fit model reproduces the multiple images with an RMS of 0.4" while simultaneously matching the X-ray data. The dark matter distribution is unimodal and centered on the brightest cluster galaxy, with a large core radius of 83+-5kpc, consistent with values reported in other strong lensing clusters. The strong lensing constraints require the inclusion of an external shear component which position angle points unambiguously towards a nearby (~1Mpc), well defined mass concentration at the same redshift in the North-West, for which we propose the naming AC114b. The spatial coverage of the XMM-Newton data encompasses the whole structure, allowing us to probe the X-ray properties of the companion cluster and the thermodynamics of AC114, providing evidence for a major merger, in line with previous signatures seen in Chandra, radio and optical spectroscopic data. Our results shed new light on the merging scenario, revealing a major merger caught in a late post-collisional phase, where AC114 is the dominant system and Ac114b has likely been stripped of its hot gas.

2512.06996 2026-04-23 quant-ph cond-mat.mes-hall

Analytic Theory and cQED Implementation of a Two-Qubit Refrigerator: Sub-100 mK Cavity Cooling from a 4 K Bath

Daryoosh Vashaee, Jahanfar Abouie

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We develop a theoretical framework for cooling a microwave cavity mode using a Poisson stream of internally correlated pairs of two-level systems and analyze its performance under realistic dissipation. Starting from a Lindblad model of a phonon-tethered cavity interacting with sequentially injected atom pairs, we derive closed-form expressions for the steady-state cavity occupation and effective temperature. Two coupling geometries are examined: a one-atom configuration, where only one member of each pair interacts with the cavity, and a two-atom configuration, where both atoms couple collectively. The single-atom model enables cooling below the phonon bath but not below the reservoir temperature, whereas the two-atom scheme exhibits enhanced refrigeration - pair correlations modify the cavity's upward and downward transition rates so that the steady-state temperature can fall well below that of the reservoir for weak phonon damping. We map the parameter space including detuning, coupling strength, damping, and intra-pair exchange, identifying cooling valleys near resonance and the crossover between reservoir- and phonon-dominated regimes. The two-atom configuration thus realizes a genuine quantum-enhanced cooling mechanism absent in the single-atom case. We further outline an experimental implementation using two superconducting qubits repeatedly prepared, coupled, and reset inside a 3D cavity. Realistic reset and flux-tuning protocols support MHz-rate interaction cycles, enabling engineered reservoirs to impose cavity temperatures of 50-120 mK even when the cryostat is at ~1 K, offering a pathway to autonomous, on-chip refrigeration of microwave modes in scalable quantum hardware.

2512.05822 2026-04-23 eess.SY cs.SY

Safe Output Regulation of Coupled Hyperbolic PDE-ODE Systems

Ji Wang, Miroslav Krstic

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This paper presents a safe output regulation control strategy for a class of systems modeled by a coupled $2\times 2$ hyperbolic PDE-ODE structure, subject to fully distributed disturbances throughout the system. A state-feedback controller is developed by the {nonovershooting backstepping} method to simultaneously achieve exponential output regulation and enforce safety constraints on the regulated output that is the state furthest from the control input. To handle unmeasurable states and external disturbances, a state observer and a disturbance estimator are designed. Explicit bounds on the estimation errors are derived and used to construct a robust safe regulator that accounts for the uncertainties. The proposed control scheme guarantees that: 1) If the regulated output is initially within the safe region, it remains there; otherwise, it will be rescued to the safety within a prescribed time; 2) The output tracking error converges to zero exponentially; 3) The observer accurately estimates both the distributed states and external disturbances, with estimation errors converging to zero exponentially; 4) All signals in the closed-loop system remain bounded. The effectiveness of the proposed method is demonstrated through a UAV delivery scenario with a cable-suspended payload, where the payload is regulated to track a desired reference while avoiding collisions with barriers.

2512.04977 2026-04-23 gr-qc astro-ph.CO hep-th

Thermodynamics vs Teleodynamics: A Cosmological Divide?

Oem Trivedi, Venkat Venkatasubramanian

Comments v2, matches the published version in PLB, 9 pages with no figures

Journal ref Phys.Lett.B 876 (2026) 140443

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We show that stationary black holes and the evolving universe belong to fundamentally different thermodynamic regimes: black holes obey ordinary Bekenstein Hawking thermodynamics, whereas cosmology necessarily follows memory-bearing teleodynamics. We show that teleodynamics is not valid for black holes, but is unavoidable in an expanding cosmology. This provides a dynamical, semi-classical realization of the thermodynamic split conjecture and identifies memory accumulation as the natural source of deviations from the area law in cosmology. Our results suggest that quantum gravity should not seek to extrapolate black hole thermodynamics to the universe, but instead must incorporate horizon memory as a fundamental microscopic ingredient and consider cosmological constructions consistent with that.

2512.02560 2026-04-23 nucl-th hep-ph

Excitation function of femtoscopic Lévy source parameters of pion pairs in EPOS4

Yan Huang, Matyas Molnar, Daniel Kincses, Mate Csanad

Comments 8 pages, 8 figures

Journal ref Phys. Lett. B 876 (2026) 140423

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Three-dimensional (3D) femtoscopic source parameters of pions provide a sensitive probe of the space-time structure of particle-emitting sources in high-energy heavy-ion collisions. Compared to one-dimensional measurements, three-dimensional femtoscopy not only provides a valuable cross-check but also offers a more complete characterization of the source geometry and its dynamical evolution. Particularly, differences between the out and side directions are sensitive to signals of a strong first-order phase transition, while the collision-energy dependence of Lévy radii may reveal non-monotonic features related to the equation of state. In this work, we systematically investigate the transverse mass (mT) and collision-energy (sqrt(sNN)) dependence of the three-dimensional femtoscopic parameters of pion pairs with Lévy-type sources in the STAR Beam Energy Scan (BES) range from sqrt(sNN) = 7.7 to 200 GeV using the EPOS4 model. The analyzed parameters include the Lévy index alpha, the correlation strength lambda, and the three-dimensional radii Rout, Rside and Rlong, corresponding to the outward, sideward, and longitudinal (beam) directions. Derived quantities such as the out-side squared radius difference and the out/side ratio are also investigated. The results show that the extracted radii Rside and Rlong decrease with increasing transverse mass and increase gradually with collision energy, while Rout shows little energy dependence. The Lévy index alpha exhibits only a mild dependence on mT and collision energy, whereas the correlation strength lambda shows a clear mT dependence and generally decreases with increasing collision energy. A comparison with EPOS3 results indicates general agreement within approximately 2sigma, with the notable exception of Rside, which is systematically smaller in EPOS4.

2512.02229 2026-04-23 math.AP

An infinite-dimensional mountain pass theorem with applications to nonlinear elliptic systems

Ablanvi Songo, Fabrice Colin

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The purpose of this paper is to establish a critical point theorem, which is an infinite-dimensional generalization of the classical generalized Mountain Pass Theorem of P. H. Rabinowitz \cite[Theorem 5.3]{Ra}. As application, we obtain the existence of at least one solution to a semilinear elliptic systems with indefinite weights in $\mathbb{R}^2$.

2512.01515 2026-04-23 physics.atom-ph

Rci-Q: an improved QED correction model for the GRASP2018 package

Karol Kozioł

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The Rci-Q package is an extension to the GRASP2018 suite, improving the model of estimating the quantum-electrodynamics corrections to the energy levels. The Flambaum-Ginges radiative potential method is used to estimate the leading self-energy correction to electron energy in many electron atoms. The new fitting prefactors to parameterize radiative potential are presented. The correction to self-energy originating from finite nucleus size is included. The Wichmann-Kroll part of the vacuum polarization potential is also implemented.

2512.00900 2026-04-23 cond-mat.str-el

Electric-field driven flat bands in the distorted sawtooth chain via the Katsura-Nagaosa-Balatsky mechanism

Vadim Ohanyan, Lusik Amiraghyan, Michael Sekania, Marcus Kollar

Comments 9 pages, 2 figures

Journal ref Zeitschrift für Naturforschung A, vol. 81, no. 4, 2026, pp. 289-298

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We investigate flat magnonic bands in a generalized sawtooth-chain model in which three sets of exchange parameters (symmetric Heisenberg exchange, axial Ising anisotropy, and antisymmetric Dzyaloshinskii-Moriya (DM) exchange) are assigned independently to each side of the triangular plaquette. If the effective Dzyaloshinskii-Moriya (DM) interaction parameters are generated via the Katsura-Nagaosa-Balatsky (KNB) mechanism of magnetoelectricity, they become explicit functions of the electric-field magnitude and direction, as well as of the lattice geometry, which in the present casen is characterized by two bond angles. We focus on the situation in which these two angles are unequal, corresponding to a distortion of the triangular plaquette. Several electric-field induced flat-band scenarios in the distorted sawtooth chain are analyzed, and expressions are derived for the electric-field strength required to drive the one-magnon excitations into a flat-band regime when the field is aligned along the lattice bonds. The saturation field and its dependence on the distortion angle are also examined. Finally, we establish a mapping between the flat-band solutions for a general DM interaction and its specific KNB-induced form. \\~ \emph{This article is dedicated to the memory of Johannes Richter.}

2512.00798 2026-04-23 math.DS math.PR

Uniform measure attractors of the distribution-dependent 2D stochastic Navier-Stokes equations driven by nonlinear noise

Jiangwei Zhang, Juntao Wu

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In this paper, we investigate the uniform measure attractors of the distribution-dependent nonautonomous 2D stochastic Navier-Stokes equations driven by nonlinear noise and subject to almost periodic external forcing. Owing to the distribution-dependent structure and the almost periodicity of the external forcing, the resulting solution process becomes an inhomogeneous Markov process, presenting significant analytical challenges. To overcome these difficulties, we propose sufficient conditions on the time-dependent external forcing and distribution-dependent nonlinear terms, and develop novel analytical estimates. As a result, we establish the existence and uniqueness of uniform measure attractors for the system. Notably, the joint continuity of the family of processes is achieved without relying on the Feller property of the distribution law operators.

2511.23156 2026-04-23 stat.AP

Design loads for wave impacts -- introducing the Probabilistic Adaptive Screening (PAS) method for predicting extreme non-linear loads on maritime structures

Sanne M. van Essen, Harleigh C. Seyffert

Journal ref van Essen, S.M. and Seyffert, H.C. (2026). Design loads for wave impacts - The Probabilistic Adaptive Screening (PAS) method for extreme non-linear hydrodynamic loads and responses of maritime structures. Ocean Eng., 357p2, 125440

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Wave impact loads on maritime structures can cause casualties, damage, pollution and operational delays. Consequently, their extreme values should be accounted for in the design of these structures. However, this is challenging, as wave impact events are both rare and highly complex, requiring both high-fidelity simulations and long analysis durations to reliably quantify the associated design loads. Moreover, existing extreme value prediction methods are neither specifically developed nor adequately validated for wave impact phenomena. We therefore introduce the new Probabilistic Adaptive Screening (PAS) method for predicting extreme non-linear loads on maritime structures. The method integrates copula-based statistical dependence modelling with multi-fidelity screening and adaptive sampling. This framework enables efficient extreme value prediction by statistically mapping low-fidelity indicator variables to high-fidelity impact loads. The method allows for efficient linear potential flow indicators to be used in the low-fidelity stage, even for strongly non-linear cases. Its statistical framework is validated against four non-linear test cases, including non-linear waves, ship vertical bending moments, green water impact loads, and slamming loads. It is concluded that PAS with optimal settings accurately estimates both the short-term distributions and extreme values in these test cases, with most probable maximum (MPM) values within 2-15% of the reference brute-force Monte-Carlo Simulation (MCS) results. In addition, PAS achieves this performance very efficiently, requiring in the order of 1-3% of the high-fidelity simulation time needed for conventional MCS. These results demonstrate that PAS can reliably reproduce the statistics of both weakly and strongly non-linear extreme load problems, while significantly reducing the associated computational cost compared to MCS.

2511.21111 2026-04-23 physics.app-ph

Topology-guided vortices in a polariton condensate

Andrea Zacheo, Marco Marangi, Nilo Mata-Cervera, Yijie Shen, Giorgio Adamo, Cesare Soci

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A major challenge in polariton fluids is achieving deterministic control over the spin texture of the macroscopic condensate wavefunction, which dictates the nucleation and dynamics of topological excitations, such as vortices, solitons, and strings. Existing approaches typically rely on external gauge fields to indirectly access the polariton pseudospin, resulting in configurations that are weakly constrained by the cavity modes and therefore highly sensitive to disorder and fluctuations. Here, we report the generation of spin polaritons constrained to the topology of a bound state in the continuum (BIC) metasurface with broken inversion symmetry carved into a polycrystalline halide-perovskite film. Geometry-induced polariton condensation under spin-momentum locking gives rise to a pair of half-vortices of opposite spin, intrinsically pinned to polarization strings, emerging as topological extensions of the vortex cores. Consequently, varying the excitation density drives a controlled displacement of the half-vortices along the trajectories imposed by the strings, hindering their mutual annihilation across an interposed topological domain wall. This approach establishes cavity geometry as an intrinsic source of spin textures to guide vortex displacement in driven quantum fluids, opening a route toward the generation of robust topological excitations within structurally disordered materials.

2511.17227 2026-04-23 cs.CC quant-ph

A Lifting Theorem for Hybrid Classical-Quantum Communication Complexity

Xudong Wu, Guangxu Yang, Penghui Yao

Comments 27 pages, 1 figure. accepted by ICALP 2026

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We investigates a model of hybrid classical-quantum communication complexity, in which two parties first exchange classical messages and subsequently communicate using quantum messages. We study the trade-off between the classical and quantum communication for composed functions of the form $f\circ G^n$, where $f:\{0,1\}^n\to\{\pm1\}$ and $G$ is an inner product function of $Θ(\log n)$ bits. To prove the trade-off, we establish a novel lifting theorem for hybrid communication complexity. This theorem unifies two previously separate lifting paradigms: the query-to-communication lifting framework for classical communication complexity and the approximate-degree-to-generalized-discrepancy lifting methods for quantum communication complexity. Our hybrid lifting theorem therefore offers a new framework for proving lower bounds in hybrid classical-quantum communication models. As a corollary, we show that any hybrid protocol communicating $c$ classical bits followed by $q$ qubits to compute $f\circ G^n$ must satisfy $c+q^2=Ω\big(\max\{\mathrm{deg}(f),\mathrm{bs}(f)\}\cdot\log n\big)$, where $\mathrm{deg}(f)$ is the degree of $f$ and $\mathrm{bs}(f)$ is the block sensitivity of $f$. For read-once formula $f$, this yields an almost tight trade-off: either they have to exchange $Θ\big(n\cdot\log n\big)$ classical bits or $\widetildeΘ\big(\sqrt n\cdot\log n\big)$ qubits, showing that classical pre-processing cannot significantly reduce the quantum communication required. To the best of our knowledge, this is the first non-trivial trade-off between classical and quantum communication in hybrid two-way communication complexity.

2511.14165 2026-04-23 hep-ph

Systematic analysis of $D_{(s)}$ meson semi-leptonic decays in the covariant light-front quark model

Hao Yang, Shao-Qin Guo, Zhi-Qing Zhang

Comments 43 pages,5 figures

Journal ref Eur.Phys.J.C 86, 363(2026)

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The weak decays of the $D_{(s)}$ meson provide a pivotal platform to advance our understanding of the Standard Model (SM) and to explore New Physics (NP). In recent years, experiments have collected a significant amount of data on the $D_{(s)}$ meson decays, particularly from BESIII, which provides substantial support for theoretical research. In this work, we systematically investigate the semi-leptonic decays of $D_{(s)}$ meson to pseudoscalar (P), scalar (S), vector (V), and axial-vector (A) mesons within the framework of the covariant light-front quark model (CLFQM). We calculate the form factors of the transitions $D_{(s)}\to P,S,V,A$ and the branching ratios of the corresponding semi-leptonic decays, then compare them with experimental data and results from other theoretical models. The form factor values of the transitions $D_{(s)}\to P, V$ obtained from the CLFQM are consistent with those of other theoretical models and available data in most cases. However, significant discrepancies are found in some specific $D_{(s)}\to S,A$ transitions, such as $D\to a_0(980), a_0(1450)$ and $D_{(s)} \to K_{1B}$, compared to other theoretical calculations. The predicted branching ratios for the semi-leptonic decays $D\to P(V)\ellν_\ell$ with $\ell=e,μ$ agree well with experimental data and other theoretical results in most decay channels, validating the reliability of the model. However, for some $D\to S(V)\ellν_\ell$ decays, tension exists among different theoretical predictions and experimental results. Further clarification of such differences is necessary. Our study provides important insights into the internal structures for some scalar and axial-vector mesons and serves as a theoretical reference for future experiments.

2511.14114 2026-04-23 cond-mat.quant-gas cond-mat.stat-mech quant-ph

Dynamics of entanglement asymmetry for space-inversion symmetry of free fermions on honeycomb lattices

Ryogo Hara, Shimpei Endo, Shion Yamashika

Comments 13 pages, 5 figures

Journal ref Phys. Rev. B 113, 144313 (2026)

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We study the entanglement asymmetry for the space-inversion symmetry of free fermions on a two-dimensional honeycomb lattice with an on-site energy imbalance between the two sublattices. We show that the entanglement asymmetry of a local subsystem exhibits nonanalytic dependence on the energy imbalance, due to the presence of Dirac points in the Brillouin zone. We also study the quench dynamics from the ground state into the inversion-symmetric point at which the energy imbalance vanishes. Under certain conditions on the subsystem geometry, the entanglement asymmetry relaxes to a finite value after the quench, revealing that the inversion-symmetry breaking in the initial ground state can persist even under the symmetric dynamics. We attribute the absence of symmetry restoration to the presence of a flat energy dispersion (flat band) in a specific direction.

2511.11386 2026-04-23 eess.SP

A Geometry Map-Based Site-Specific Propagation Channel Model for Urban Scenarios

Junzhe Song, Ruisi He, Mi Yang, Zhengyu Zhang, Shuaiqi Gao, Xiaoying Zhang, Bo Ai

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With the rapid deployments of 5G and 6G networks, accurate modeling of urban radio propagation has become critical for system design and network planning. However, conventional statistical or empirical models fail to fully capture the influence of detailed geometric features on site-specific channel variances in dense urban environments. In this paper, we propose a geometry map-based propagation channel model that directly extracts key parameters from a 3D geometry map and incorporates the Uniform Theory of Diffraction (UTD) to recursively compute multiple diffraction fields, thereby enabling accurate prediction of site-specific large-scale path loss and time-varying Doppler characteristics in urban scenarios. A well-designed identification algorithm is developed to efficiently detect buildings that significantly affect signal propagation. The proposed model is validated using urban measurement data, showing excellent agreement of path loss in both line-of-sight (LOS) and nonline-of-sight (NLOS) conditions. In particular, for NLOS scenarios with complex diffractions, it outperforms the 3GPP and simplified models, reducing the RMSE by 7.1 dB and 3.18 dB, respectively. Doppler analysis further demonstrates its accuracy in capturing time-varying propagation characteristics, confirming the scalability and generalization of the model in urban environments.

2511.10553 2026-04-23 math.DG math.AP

Sign-changing solutions to the Yamabe problem on manifolds with boundary

Mónica Clapp, Benedetta Pellacci, Angela Pistoia

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Let $(M, g)$ be a compact Riemannian manifold with boundary. The Yamabe problem concerning the existence of a metric conformally equivalent to $g$ having constant scalar curvature on $M$ and constant mean curvature on its boundary is equivalent, in analytic terms, to finding a positive solution to a nonlinear boundary-value problem with critical growth. While the existence of positive solutions to this problem is by now well understood, the existence of sign-changing (nodal) solutions remains largely open. In this work we establish the existence of least-energy sign-changing solutions when the manifold is positive and the mean curvature of the boundary is a non-negative constant. More precisely, we prove that if $n\ge7$ and $M$ has a nonumbilic boundary point, then the problem admits least-energy nodal solutions. Our approach is variational and relies on the analysis of suitable conformal invariants and sharp energy estimates.

2511.09974 2026-04-23 cond-mat.other

Chiral orbital/spin textures and Edelstein effects in monolayer Janus TMDs

Pratik Sahu, Sashi Satpathy, Birabar Ranjit Kumar Nanda

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We investigate the orbital and spin Edelstein effect(OEE and SEE) in two-dimensional Janus transition metal dichalcogenides (TMDs) of the form MXX$^\prime$ $(M = Mo,\ W,\ Nb;\ X/X^\prime = S,\ Se,\ Te)$ with the aid of density functional theory calculations and tight-binding model Hamiltonian studies. The chalcogen layers $X$ and $X^\prime$, break the mirror symmetry to introduce an internal electric field $E_{int}$ normal to the plane, which is responsible for OEE and SEE. Our results show that in a non-Janus framework, the wavefunctions at the valence and conduction bands are dominated with the $|x^2-y^2>$, $|xy>$, and $|z^2>$ orbitals. Due to the $E_{int}$ of the Janus system, these orbitals are now intermixed with the $|xz>$ and $|yz>$ orbitals to produce a robust orbital texture around the valleys $Γ,K$ and $K^\prime$. The spin orbit coupling, in addition to the formation of a spin texture, introduces a chirality reversal to the orbital texture. An applied in plane electric field creates both OEE and SEE with the former being one order higher in magnitude. This makes the Janus materials promising for spin-orbitronics. Our work paves the way for further experimental exploration for orbital and spin orbital torque in Janus TMDs.

2511.09464 2026-04-23 eess.SP

Scalable Long-Term Beamforming for Massive Multi-User MIMO

Ali Rasteh, Amirreza Kiani, Marco Mezzavilla, Sundeep Rangan

Comments Submitted to the IEEE Transactions on Wireless Communications

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Fully digital massive MIMO systems with large numbers (1000+) of antennas offer dramatically increased capacity gains from spatial multiplexing and beamforming. Designing digital receivers that can scale to these array dimensions presents significant challenges regarding both channel estimation overhead and digital computation. In the massive MIMO setting, long-term beamforming is widely-used since it offers significant reductions in both computation and channel estimation overhead. Long-term beamforming operates by projecting the data onto a low-dimensional subspace that can be tracked at a relatively slow time-scale from the long-term channel parameters. In this setting, we show how to optimally compute the projection matrix to maximize a capacity upper-bound using a matrix inverse square root. Computationally efficient methods are then presented to perform the matrix computation. The methods can be realized with matrix-matrix multiplies, making them amenable to systolic array implementations in hardware. Error analysis bounds on the degradation in the SINR for users are derived. Ray tracing simulations in a realistic rural uplink setting show minimal loss relative to complete instantaneous MMSE beamforming while offering significant overhead and computational gains.

2511.05172 2026-04-23 physics.ins-det

Proof-of-concept of a xenon-based cryogenic heat pump demonstrator for future liquid xenon observatories

P. Schulte, D. Wenz, L. Althueser, R. Braun, V. Hannen, C. Huhmann, D. Koke, Y. -T. Lin, P. Unkhoff, C. Weinheimer

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This manuscript details the proof-of-concept of a small-scale cryogenic heat pump demonstrator, a technology designed to enable high-flow xenon distillation systems for the removal of $^{222}$Rn in future liquid xenon observatories such as the XLZD experiment. The heat pump demonstrator operates on a left-turning Clausius-Rankine cycle, utilizing xenon as a phase-changing working medium. The design aims to fully hermetically separate the heat pump from the radon removal system, simplifying material cleanliness and maintenance compared to currently operating systems. Two demonstration tests were conducted at nominal pressures of $3.3\,\mathrm{bar}$ and $4.3\,\mathrm{bar}$, utilizing a cold head and electrical heaters to mimic the behavior of a xenon distillation system. In both measurements, the demonstrator achieved a cooling and heating power of $(118\pm3)\,\mathrm{W}$ and $(121\pm3)\,\mathrm{W}$, respectively. This is sufficient to operate a small distillation system with a virtual purification mass flow of about $3.1\,\mathrm{kg/h}$, while consuming $386\pm1\,\mathrm{W}$ electrical power. Compered to currently operating applications using commercial cold heads driven by helium compressors, which typically require about $6\,\mathrm{kW}$ of electrical power, this is significantly lower. The presented proof-of-concept heat pump demonstrator is further put into perspective with the currently planned XLZD experiment using a simplified scaling model. This model indicates that a radon removal system with a purification mass flow of $1600\,\mathrm{kg/h}$ and a required cooling and heating power of about $60\,\mathrm{kW}$ each, will be sufficient to cover a variety of different detector masses and background conditions.

2511.04561 2026-04-23 math.AG math.CV

Moduli space of connections on rational irregular curves

Mattia Morbello

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We study the compactification of the moduli space of a certain class of rank-two irregular connections on the Riemann sphere, presenting one double pole and two simple poles. To construct the compactification explicitly, we identify a class of such irregular connections with the data of a rational irregular curve together with an extra complex parameter. As a first step, we compactify the moduli space of rational irregular curves using a technique inspired by the Kapranov's compactification of the spaces $\mathcal{M}_{0,n}$. We then introduce the notion of irregular stable nodal curve to describe the curves lying on the boundary components, in the spirit of the work of Deligne and Mumford. Second, we study the behaviour of the extra complex parameter to complete the compactification, obtaining a three dimensional quasi-projective variety $\mathfrak{Con}^V_Θ$ that extends the Okamoto compactification.

2511.03486 2026-04-23 cs.CR

Federated Anonymous Blocklisting across Service Providers and its Application to Group Messaging

David Soler, Carlos Dafonte, Manuel Fernández-Veiga, Ana Fernández Vilas, Francisco J. Nóvoa

Comments 32 pages, 5 figures. Accepted in IEEE Transactions on Emerging Topics in Computing

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Instant messaging has become one of the most used methods of communication online, which has attracted significant attention to its underlying cryptographic protocols and security guarantees. Techniques to increase privacy such as End-to-End Encryption and pseudonyms have been introduced. However, online spaces such as messaging groups still require moderation to prevent misbehaving users from participating in them, particularly in anonymous contexts.. In Anonymous Blocklisting (AB) schemes, users must prove during authentication that none of their previous pseudonyms has been blocked, preventing misbehaving users from creating new pseudonyms. In this work we propose an alternative Federated Anonymous Blocklisting (FAB) in which the centralised Service Provider is replaced by small distributed Realms, each with its own blocklist. Realms can establish trust relationships between each other, such that when users authenticate to a realm, they must prove that they are not blocked in any of its trusted realms. We provide an implementation of our proposed scheme; unlike existing AB constructions, the performance of ours does not depend on the current size of the blocklist nor requires processing new additions to the blocklist. We also demonstrate its applicability to real-world messaging groups by integrating our FAB scheme into the Messaging Layer Security protocol.

2511.02394 2026-04-23 cond-mat.quant-gas nlin.PS

The bulk modulus of three-dimensional quantum droplets

Zibin Zhao, Guilong Li, Zhaopin Chen, Huan-Bo Luo, Bin Liu, Boris A. Malomed, Yongyao Li

Comments 9 pages, 5 figures, and 66 References

Journal ref Physical Review A 113, 043315 (2026)

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Quantum droplets (QDs), formed by ultradilute quantum fluids under the action of the Lee-Huang-Yang (LHY) effect, provide a unique platform for investigating a wide range of macroscopic quantum effects. Recent studies of QDs' breathing modes and collisional dynamics have revealed their compressibility and extensibility, which suggests that their elasticity parameters can be identified. In this work we derive the elastic bulk modulus (BM) of QDs by means of theoretical analysis and numerical simulations and establish a relation between the BM and the eigenfrequency of the QD's intrinsic vibrations. The analysis reveals the dependence of the QD's elasticity on the particle number and the strength of interparticle interactions. We additionally provide a realistic estimate of the bulk modulus for the system, yielding a concrete physical value that may serve as a reference for future experimental measurements. Taken together, these results also point to possibilities for realizing elastic media governed by the LHY effect.

2511.02323 2026-04-23 astro-ph.CO

Weak-Lensing Analysis of the Galaxy Cluster Abell 85: Constraints on the Merger Scenarios of Its Southern Subcluster

Soojin Kim, Kim HyeongHan, Wonki Lee, Jong-In Park, Myungkook James Jee, Ho Seong Hwang

Comments 21 pages, 11 figures, 1 table, Accepted for publication in ApJ

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Abell 85 is a nearby (z=0.055) galaxy cluster that hosts a sloshing cool core, a feature commonly reported in relaxed clusters. However, the presence of multiple past and ongoing mergers indicates that it is an active node within the Abell 85/87/89 complex. We present a weak gravitational lensing (WL) analysis using Subaru Hyper Suprime-Cam imaging data to understand its assembly history by investigating the dark matter components of the substructures. Our mass reconstruction resolves three substructures associated with the brightest cluster galaxy (main), the southern (S) subcluster, and the southwestern (SW) subcluster, with WL peak significances of $> 6σ$, $> 5σ$, and $> 4σ$, respectively. The location of these mass peaks are consistent with those of the member galaxies. We estimate the masses of the main cluster ($M_{200c,main} = 2.91 \pm 0.72 \times 10^{14}\ M_\odot$) and the S subcluster ($M_{200c,S} = 1.23 \pm 0.52 \times 10^{14}\ M_\odot$) by fitting a multi-halo Navarro-Frenk-White profile. This $\sim$2:1 mass ratio indicates that the system is undergoing a major merger that is actively shaping the current dynamical state of Abell 85. Incorporating X-ray observations, we discuss the merger phase of the S subcluster and further examine the star-forming activity along the putative filament extending southeast of Abell 85.

2511.01995 2026-04-23 hep-ex

Inclusive and differential measurements of the $\mathrm{t\bar{t}}γ$ cross section and the $\mathrm{t\bar{t}}γ$ / $\mathrm{t\bar{t}}$ cross section ratio in proton-proton collisions at $\sqrt{s}$ = 13 TeV

CMS Collaboration

Comments Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/TOP-23-002 (CMS Public Pages)

Journal ref JHEP 04 (2026) 086

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英文摘要

Inclusive and differential cross section measurements of top quark pair ($\mathrm{t\bar{t}}$) production in association with a photon ($γ$) are performed as a function of lepton, photon, top quark, and $\mathrm{t\bar{t}}$ kinematic observables, using data from proton-proton collisions at $\sqrt{s}$ = 13 TeV, corresponding to an integrated luminosity of 138 fb$^{-1}$, collected at the CERN LHC with the CMS detector. Events containing two leptons (electrons or muons) and a photon in the final state are considered. The fiducial cross section of $\mathrm{t\bar{t}}γ$ is measured to be 137 $\pm$ 8 fb, in a phase space including events with a high momentum, isolated photon. The fiducial cross section of $\mathrm{t\bar{t}}γ$ is also measured to be 56 $\pm$ 5 fb when considering only events where the photon is emitted in the production part of the process. Both measurements are in agreement with the theoretical predictions, of 126 $\pm$ 19 fb and 57 $\pm$ 5 fb, respectively. Differential measurements are performed at the particle and parton levels. Additionally, inclusive and differential ratios between the cross sections of $\mathrm{t\bar{t}}γ$ and $\mathrm{t\bar{t}}$ production are measured. The inclusive ratio is found to be 0.0133 $\pm$ 0.0005, in agreement with the standard model prediction of 0.0127 $\pm$ 0.0008. The top quark charge asymmetry in $\mathrm{t\bar{t}}γ$ production is also measured to be $-$0.012 $\pm$ 0.042, compatible with both the standard model prediction and with no asymmetry.

2510.26288 2026-04-23 cond-mat.str-el

Laser-Induced Commensurate-Incommensurate Transition of Charge Order in a Hubbard Superlattice

Hua Chai, Zhenyu Cheng, Qinxin Hu, Zhongbing Huang, Xiang Hu, Xuedong Tian, Liang Du

Comments 8 pages, 4 figures

Journal ref Phys. Rev. B 113, 165134 (2026)

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英文摘要

We investigate the nonequilibrium dynamics of charge density waves in a pumped one-dimensional Hubbard superlattice with staggered onsite Coulomb interactions at half-filling, using time-dependent exact diagonalization. In equilibrium, the system exhibits commensurate charge correlations consistent with the superlattice periodicity. Under laser excitation, the charge correlation function exhibits distinct behaviors across four representative frequencies, spanning both linear and nonlinear optical regimes. Notably, we observe a laser-induced commensurate-to-incommensurate transition in the charge order, manifested by a shift in the peak wavevector of the charge structure factor. This transition is driven by sublattice-selective doublon-holon dynamics, where the laser frequency and intensity determine whether excitations predominantly destabilize the charge order on the weakly or strongly interacting sublattice. Our analysis of the excitation spectrum and site-resolved correlation dynamics reveals the underlying mechanisms of this transition. These results suggest a promising optical strategy for controlling charge order in superlattice-based quantum materials.

2510.21742 2026-04-23 q-bio.NC cond-mat.dis-nn cs.NE hep-th physics.bio-ph

Statistics of correlations in nonlinear recurrent neural networks

German Mato, Facundo Rigatuso, Gonzalo Torroba

Comments 39 pages, 9 figures

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英文摘要

The statistics of correlations are central quantities characterizing the collective dynamics of recurrent neural networks. We derive exact expressions for the statistics of correlations of nonlinear recurrent networks in the limit of a large number N of neurons, including systematic 1/N corrections, in the regime of Gaussian quenched disorder. Our approach uses a path-integral representation of the network stochastic dynamics, which reduces the description to a few collective variables and enables efficient computation. This generalizes previous results on linear networks to include a wide family of nonlinear activation functions, which enter as interaction terms in the path integral. These interactions can resolve the instability of the linear theory and yield a strictly positive participation dimension. We present explicit results for power-law activations, revealing scaling behavior controlled by the network coupling. In addition, we introduce a class of activation functions based on Pade approximants and provide analytic predictions for their correlation statistics. Numerical simulations confirm our theoretical results with excellent agreement. We also compare with previous works that have studied the complementary case with annealed disorder, and based on this we propose a new self-consistent equation for the more general case of colored noise.

2510.18958 2026-04-23 hep-ph astro-ph.CO gr-qc

Sensitivity forecasts for gravitational-wave detectors to dark matter decaying into gravitons

Jose A. R. Cembranos, Álvaro Cendal

Comments 17 pages, 4 figures. Minor changes (improved figure captions and formatting)

Journal ref JCAP 03 (2026) 055

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英文摘要

Dark matter may not be perfectly stable, and its decay could generate distinctive gravitational-wave signatures. In this work, we present model-independent predictions for the stochastic gravitational-wave background arising from the decay of ultralight dark matter into gravitons. Within this framework, we forecast the sensitivity reach of current and forthcoming gravitational-wave detectors to such signals.

2510.18787 2026-04-23 cs.SE

Characterizing Datasets for LLM-based Requirements Engineering: A Systematic Mapping Study

Quim Motger, Carlota Catot, Xavier Franch

Comments Accepted at the 30th International Conference on Evaluation and Assessment in Software Engineering

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英文摘要

Large Language Models (LLMs) depend on high-quality, domain-specific natural language datasets. This dependency is particularly pronounced in Requirements Engineering (RE), where core activities rely on textual artifacts such as requirements, specifications, and stakeholder feedback. Despite the increasing use of LLMs in RE, data scarcity remains a widely reported limitation. While several datasets support LLM-based RE research, they are scattered across studies and lack systematic characterization, hindering reuse, comparability and assessment. This paper addresses this gap by examining which public datasets are used in LLM-based RE, how they can be consistently characterized, and which RE tasks and dataset properties remain under-represented. We report on a systematic mapping study of 45 primary studies referencing 62 publicly available datasets. Each dataset is characterized using a structured scheme covering multiple dimensions, including relevant descriptors such as artifact type, granularity, RE activity, supported task, application domain, and language, among others. The results reveal notable imbalances, including an incomplete adoption of open-science practices, limited dataset support for elicitation activities, and a lack of language and socio-technical diversity. The resulting catalogue and characterisation scheme support informed dataset selection, comparison, and reuse, contributing to stronger empirical foundations for LLM-based RE research and evaluation.

2510.17481 2026-04-23 econ.GN q-fin.EC

Universalization and the Origins of Fiscal Capacity

Esteban Muñoz-Sobrado

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英文摘要

This paper proposes a model of tax compliance and fiscal capacity grounded in universalization reasoning. Citizens partially internalize the consequences of concealment by imagining a world in which everyone acted similarly, linking their compliance decisions to the perceived effectiveness of public spending. A selfish elite chooses between public goods and private rents, taking compliance as given. In equilibrium, citizens' moral internalization expands the feasible tax base and induces elites to allocate resources toward provision rather than appropriation. When the value of public spending is uncertain, morality enables credible reform: high-value elites can signal their type through provision, prompting citizens to increase compliance and raising fiscal capacity within the same period. The analysis thus identifies a moral channel through which states may escape low-capacity traps even under weak institutions.

2510.15151 2026-04-23 hep-ph

Enhancing di-jet resonance searches via a final-state radiation jet tagging algorithm

Bingxuan Liu, Yuxuan Shen, Yuanshunzi Sui

Comments To be published in Chinese Physics C

Journal ref Chin.Phys. 50 (2026) 4, 043106

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英文摘要

In this article, we investigate the possibility of enhancing the di-jet resonance searches by tagging the final state radiation (FSR) jet, using an event-level deep neural network. It is found that solely relying on the 4-momenta of the leading three jets allows the algorithm to achieve good discriminating power that can identify the hardest FSR jet in signal, while rejecting other soft jets. Once the invariant mass is corrected with the tagged FSR jet, the mass resolution of the signal is greatly enhanced, and the sensitivity of the search is also improved by more than 10%. By crafting the input variables carefully, the algorithm introduces minimal mass sculpting for the background, and its applicability extends to a broad mass range. This work proves that FSR jet tagging can potentially enhance the di-jet resonance searches, suiting various stages of the physics programmes at the Large Hadron Collider (LHC) and High-Luminosity LHC (HL-LHC).