广义相对论与量子宇宙学

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[1] arXiv:2511.13951 [中文pdf, pdf, html, 其他]

标题： 质量维度一费米子的厄米特形式：平直时空和弯曲时空 显示英文标题

标题： Hermitian formulation for mass dimension one fermions: Flat and curved space-times

Gregory Patellis, Danai Roumelioti, Stelios Stefas, George Zoupanos

评论： 12页，2图（应《MPLA》特邀为达拉姆·阿胡利亚教授纪念专刊撰稿）

主题： 广义相对论与量子宇宙学 (gr-qc) ; 高能物理 - 理论 (hep-th)

在整个论文中，我们通过部分回顾Elko的厄米性进行讨论，基于Elko旋量提出了相互作用的一阶质量维度费米子的厄米形式。它包括关于可重整化的重要观察以及对一些允许相互作用的研究。除了这些点之外，由于暗物质现象学主要与引力相关，我们引入了原始备注，说明如何将厄米规定轻松推广以包含弯曲时空，考虑到Elko旋量结构的定义。我们确立了Elko对偶性源自更基本结构的路径积分公式。这使得可以将弯曲背景时空以及量子引力纳入我们的研究中。 显示英文摘要

Throughout this paper, we conduct our discussion by a partial review of Elko's Hermiticity, introducing the Hermitian formulation for interacting mass dimension one fermions based on Elko spinor. It includes pivotal observations about renormalizability and the study of some allowed interactions. Beyond these points, since dark-matter phenomenology is mainly connected to gravitation, we introduce original remarks on how the Hermitian prescription can be readily generalized to include curved space-time, considering the very definition of the Elko spinor structure. We establish the Elko dual as arising from the path-integral formulation of a more fundamental structure. It enables one to include a curved background space-time and also quantum gravity into our investigations.

[2] arXiv:2510.11761 [中文pdf, pdf, html, 其他]

标题： 弯曲时空中的振动原子的加速度辐射 显示英文标题

标题： Acceleration radiation from vibrating atoms in Schwarzschild spacetime

Marc Geiller, Pujian Mao, Antoine Vincenti

评论： 20页，3个图。更改了标题并改进了摘要。在正文中添加了一些小的澄清说明。欢迎提出意见

主题： 广义相对论与量子宇宙学 (gr-qc) ; 高能物理 - 理论 (hep-th)

受Scully \textit{等.} [ \textcolor{blue}{过程 自然 科学院 科学 115, 8131 (2018)} ] 和Dolan \textit{等.}[ \textcolor{blue}{新物理学杂志 22, 033026 (2020)} ] 工作的启发，我们研究了在施瓦茨希尔德黑洞外部以固定平均半径 $R_0$进行小振幅径向振荡的两能级Unruh-DeWitt探测器产生的加速辐射。 无质量标量场在Boulware真空下被量子化，以隔离曲率调制的加速效应，而不考虑热霍金背景。 在(1+1)径向简化模型中，并使用一阶时间依赖微扰，我们计算了周期平均跃迁率（或Floquet跃迁率）。 The resulting particle emission spectrum exhibits a thermal Bose-Einstein-type profile with periodic trajectory yielding a Floquet resonance condition $nΩ> ω_0$ and a closed-form expression for the Floquet transition rate $\overline{P}_n$, which reduces to the flat Minkowski spacetime result as $R_0\to\infty$, in agreement with Near the horizon, $f(R_0)<1$ enhances the effective Bessel argument by $1/\sqrt{f(R_0)}$, providing a simple analytic demonstration of curvature/redshift amplification of acceleration radiation. In particular, the spectrum weighted by the Bessel function becomes ill-defined near the black hole horizon as $R_{0}\rightarrow 2M$, possibly manifesting the well-known pathological behavior of the Boulware vacuum state. We discuss the regime of validity (small amplitude, $R_0$ away from the horizon) and outline the extensions to (3+1) dimensions, including density-of-states and greybody factors, and to alternative vacuum choices. Our results offer an analytically tractable link between flat-space vibrating atom proposals and black-hole spacetimes. 显示英文摘要

Motivated by the work of Scully \textit{et al.} [ \textcolor{blue}{Proc. Nat. Acad. Sci. 115, 8131 (2018)}] and Dolan \textit{et al.}[ \textcolor{blue}{New J. Phys. 22, 033026 (2020)}], we study the acceleration radiation from a two-level Unruh-DeWitt detector that undergoes small-amplitude radial oscillations at fixed mean radius $R_0$ outside a Schwarzschild black hole. The massless scalar field is quantized in the Boulware vacuum to isolate curvature-modulated acceleration effects without a thermal Hawking background. Working in a (1+1) radial reduction and using first-order time-dependent perturbation, we evaluate the period-averaged transition rate (or the Floquet transition rate). The resulting particle emission spectrum exhibits a thermal Bose-Einstein-type profile with periodic trajectory yielding a Floquet resonance condition $nΩ> ω_0$ and a closed-form expression for the Floquet transition rate $\overline{P}_n$, which reduces to the flat Minkowski spacetime result as $R_0\to\infty$, in agreement with Near the horizon, $f(R_0)<1$ enhances the effective Bessel argument by $1/\sqrt{f(R_0)}$, providing a simple analytic demonstration of curvature/redshift amplification of acceleration radiation. In particular, the spectrum weighted by the Bessel function becomes ill-defined near the black hole horizon as $R_{0}\rightarrow 2M$, possibly manifesting the well-known pathological behavior of the Boulware vacuum state. We discuss the regime of validity (small amplitude, $R_0$ away from the horizon) and outline the extensions to (3+1) dimensions, including density-of-states and greybody factors, and to alternative vacuum choices. Our results offer an analytically tractable link between flat-space vibrating atom proposals and black-hole spacetimes.

[3] arXiv:2511.13812 [中文pdf, pdf, html, 其他]

标题： 轻于QCD轴子对中子星潮汐变形性的影响 显示英文标题

标题： Effects of Lighter-than-QCD Axions on Neutron Star Tidal Deformability

Saul A. Teukolsky

评论： 18页，10图，5页的附录

主题： 高能物理 - 现象学 (hep-ph) ; 高能天体物理现象 (astro-ph.HE) ; 广义相对论与量子宇宙学 (gr-qc)

轻于QCD轴子的有限密度修正可以反转有效轴子势，从而在致密天体内部产生非平凡的轴子场。 我们进行了首次在1+1维广义相对论中对轻于QCD轴子在中子星中的完整动力学的数值研究，并将分析区域扩展到具有千米尺度康普顿波长的低质量轴子。 我们计算了轴子场对中子星的引力效应，并表明对于广泛的轴子质量和衰变常数，中子星的性质，如质量、半径和致密性，都会在一级量级上受到影响。 这一结果表明，中子星的近似普遍潮汐变形-致密性关系被非平凡地破坏，并可以作为探测轻于QCD轴子的工具，而无需依赖未知的核方程状态。 我们评论了未来中子星引力波观测在轴子研究中的潜力，以及本工作在其他新物理信号应用方面的可能性。 显示英文摘要

Finite density corrections to the lighter-than-QCD axion can invert the effective axion potential, sourcing a non-trivial axion field inside dense objects. We perform the first numerical study of the complete dynamics of the lighter-than-QCD axion in a neutron star in 1+1 general relativity, extending the region of analysis to low-mass axions with kilometer-scale Compton wavelengths. We calculate gravitational effects of the axion field on the neutron star and show that for a broad range of axion masses and decay constants, neutron star properties, such as the mass, radius, and compactness, are affected at the order-1 level. This result indicates that approximate universal tidal deformability-compactness relation for neutron stars is non-trivially broken and can serve as a probe of lighter-than-QCD axions, independent of the unknown nuclear equation of state. We comment on the potential for axion studies with future gravitational-wave observations of neutron stars and applications of this work to other new physics signatures.

[4] arXiv:2507.14498 [中文pdf, pdf, html, 其他]

标题： 由JWST揭示的碰撞星风双星Apep中的尘埃形成和演化 显示英文标题

标题： The formation and evolution of dust in the colliding-wind binary Apep revealed by JWST

Saul A. Teukolsky

评论： 19页，10图，1表，已接受发表于ApJ

主题： 太阳与恒星天体物理学 (astro-ph.SR) ; 地球与行星天体物理学 (astro-ph.EP) ; 星系的天体物理学 (astro-ph.GA) ; 天体物理学的仪器与方法 (astro-ph.IM)

富含碳的沃尔夫-拉叶（WR）星是银河环境中碳质尘埃的重要贡献者，然而这些恒星周围尘埃的形成和后续演化机制和条件仍然是开放性问题。 在这里，我们展示了对WR+WR碰撞风双星Apep的JWST观测结果，揭示了一系列复杂的嵌套同心尘埃壳层，这些壳层具有丰富的细节结构。 相邻壳层之间这些次级结构的显著规律性表明，存在一个精确重复的形成机制，并且有高度稳定的流出物，在进入星际介质0.6 pc（假设距离为2.4 kpc）后仍保持一致的形态。 同心尘埃壳层显示出与球形流出略有偏离，这可能反映了沿偏心双星轨道的轨道调制或恒星风的非球形性。 追踪多层结构中尘埃的演化，我们测量了尘埃温度的演化，可以大致用非晶态碳成分在辐射热平衡下进行描述。 温度分布和轨道周期提出了新的距离约束，支持Apep比之前估计的距离更远，从而减少了之前被认为具有该系统的视线方向和天球平面风速差异。 显示英文摘要

Carbon-rich Wolf-Rayet (WR) stars are significant contributors of carbonaceous dust to the galactic environment, however the mechanisms and conditions for formation and subsequent evolution of dust around these stars remain open questions. Here we present JWST observations of the WR+WR colliding-wind binary Apep which reveal an intricate series of nested concentric dust shells that are abundant in detailed substructure. The striking regularity in these substructures between successive shells suggests an exactly repeating formation mechanism combined with a highly stable outflow that maintains a consistent morphology even after reaching 0.6 pc (assuming a distance of 2.4 kpc) into the interstellar medium. The concentric dust shells show subtle deviations from spherical outflow, which could reflect orbital modulation along the eccentric binary orbit or non-sphericity in the stellar wind. Tracking the evolution of dust across the multi-tiered structure, we measure the dust temperature evolution that can broadly be described assuming an amorphous carbon composition in radiative thermal equilibrium with the central stars. The temperature profile and orbital period place new distance constraints that support Apep being at a greater distance than previously estimated, reducing the line-of-sight and sky-plane wind speed discrepancy previously thought to characterise the system.

[5] arXiv:2509.05700 [中文pdf, pdf, html, 其他]

标题： 纠缠熵与动态黑洞的热力学 显示英文标题

标题： Entanglement Entropy and Thermodynamics of Dynamical Black Holes

Eryk Buk, Denis Dobkowski-Ryłko, Jerzy Lewandowski, Maciej Ossowski

评论： 33页，3张图；v2：小的改进，拼写错误已修复，增加了参考文献；

主题： 高能物理 - 理论 (hep-th) ; 广义相对论与量子宇宙学 (gr-qc)

我们探讨了基于Hollands-Wald-Zhang最近提出的动态黑洞熵的热力学和纠缠性质。 我们首先提供了一个直接证明，在一阶扰动下，任何 $f(R)$ 理论中的动态黑洞熵等于在广义似是而非视界上计算的Wald熵。 然后，我们使用事件视界和似是而非视界作为纠缠表面，显式计算了引力纠缠熵，并表明只有似是而非视界方案能够重现满足物理过程第一定律的正确动态黑洞熵。 此外，我们通过将修改后的冯·诺依曼熵识别为跨越（广义）似是而非视界的物质纠缠，重新解释了广义第二定律。 这使我们能够将总熵表示为在这条表面上计算的重整化广义熵，适用于爱因斯坦引力和 $f(R)$ 引力。 显示英文摘要

We explore the thermodynamic and entanglement properties of dynamical black holes based on the recently proposed dynamical black hole entropy by Hollands-Wald-Zhang. We first provide a direct proof that, under first order perturbations, the dynamical black hole entropy in any $f(R)$ theory equals the Wald entropy evaluated on the generalized apparent horizon. Then, we compute the gravitational entanglement entropy explicitly using both the event horizon and the apparent horizon as the entangling surfaces, and show that only the apparent horizon prescription reproduces the correct dynamical black hole entropy satisfying the physical process first law. Furthermore, we reinterpret the generalized second law by identifying the modified von Neumann entropy as the matter entanglement across the (generalized) apparent horizon. This allows us to express the total entropy as the renormalized generalized entropy evaluated on this surface for both Einstein's gravity and $f(R)$ gravity.

[6] arXiv:2509.03308 [中文pdf, pdf, html, 其他]

标题： $\widetilde{W}^{1+}$ 子类：扩展黑洞热力学的拓扑分类 显示英文标题

标题： $\widetilde{W}^{1+}$ subclass: Extending the topological classification of black hole thermodynamics

Matteo Della Rocca, Thomas F.M. Spieksma, Francisco Duque, Leonardo Gualtieri, Vitor Cardoso

评论： 10页，5图，4表，即将发表于PRD

主题： 高能物理 - 理论 (hep-th) ; 广义相对论与量子宇宙学 (gr-qc)

在本文中，我们识别出一个新颖的拓扑子类，称为$\widetilde{W}^{1+}$，在高奇数维、多重旋转Kerr-AdS黑洞热力学中。 这一发现将已知的拓扑分类扩展到了此前已知的五个类别和两个子类之外。 $\widetilde{W}^{1+}$子类表现出一种独特且此前未报告的稳定性特征：它在低温极限下允许一个热力学稳定的较小黑洞状态，而在高温极限下，相空间同时包含一个稳定的较大黑洞、一个稳定的较小黑洞和一个不稳定的较小黑洞状态。 我们的分析将黑洞解视为拓扑缺陷，揭示了比之前理解的更丰富的黑洞热力学景观，并要求对拓扑分类方案进行扩展以适应这种新的现象学。 显示英文摘要

In this paper, we identify a novel topological subclass, dubbed $\widetilde{W}^{1+}$, in the thermodynamics of higher odd-dimensional, multiply rotating Kerr-AdS black holes. This discovery extends the established topological classification beyond the five classes and two subclasses previously known. The $\widetilde{W}^{1+}$ subclass exhibits a unique and previously unreported stability profile: it admits a thermodynamically stable small black hole state in the low-temperature limit, while in the high-temperature limit, the phase space simultaneously contains one stable large black hole, one stable small black hole, and one unstable small black hole state. Our analysis, which treats black hole solutions as topological defects, reveals a richer landscape of black hole thermodynamics than previously understood and necessitates an expansion of the topological classification scheme to accommodate this new phenomenology.

[7] arXiv:2506.21759 [中文pdf, pdf, html, 其他]

标题： 从广义能量守恒中得到的德西特空间中的新例外EFTs 显示英文标题

标题： New Exceptional EFTs in de Sitter Space from Generalised Energy Conservation

Gabriel Brandão de Gracia, Rodolfo José Bueno Rogerio

期刊参考： 物理评论快报 135，201501 2025年11月13日发表

主题： 高能物理 - 理论 (hep-th) ; 广义相对论与量子宇宙学 (gr-qc)

我们发现德西特空间中的异常有效场论（EFTs）与在四维德西特扩展的庞加莱区域中定义的S矩阵的\textit{广义能量守恒}（GEC）概念之间存在令人惊讶的关系。 通过要求这样的S矩阵仅当输入和输出态的总能量相等时才具有支持，我们约束了生活在德西特表示异常序列中的自相互作用标量理论中的耦合常数。 我们重新发现了狄拉克-玻恩-英费尔德（DBI）和特殊伽利略理论，当增加共形维度时，我们发现了新的异常理论的证据，其中四点标量自相互作用仅由一个耦合常数唯一确定。 我们猜想，对于每个整数共形维度$Δ\geq 4$，至少存在一个可以通过GEC完全确定的异常EFT。 显示英文摘要

We discover a surprising relationship between exceptional effective field theories (EFTs) in de Sitter space and a notion of \textit{generalised energy conservation} (GEC) of an S-matrix defined in an extended Poincaré patch of four-dimensional de Sitter. By demanding that such an S-matrix only has support when the total energies of in and out states are equal, we constrain the coupling constants in theories of self-interacting scalars living in the exceptional series of de Sitter representations. We rediscover the theories of Dirac-Born-Infeld (DBI) and Special Galileon, and when increasing the conformal dimension we find evidence for new exceptional theories where the four-point scalar self interactions are uniquely fixed in terms of a single coupling constant. We conjecture that for each integer conformal dimension $Δ\geq 4$, there is at least one exceptional EFT that can be entirely fixed by GEC.

[8] arXiv:2506.09540 [中文pdf, pdf, html, 其他]

标题： 从静态球对称几何中得到协变动力学 显示英文标题

标题： Covariant dynamics from static spherically symmetric geometries

Bela Nelson, Allison Powell, Jennie Traschen

评论： 6页，包括附录；v3：根据审稿人的意见进行了重大修改，包括重写的摘要，强调了我们工作的双重贡献。v2：根据审稿人的意见进行了重大修改。

主题： 广义相对论与量子宇宙学 (gr-qc)

这项工作揭示了广义协变性与Birkhoff定理之间的基本联系。 我们将Birkhoff定理从广义相对论扩展到在哈密顿框架中表述的广泛类别的广义协变引力理论。 相反，我们证明每个单参数的静态、球对称时空族确定了一类协变理论，每种理论都以其整个真空解空间为该时空族。 我们的系统且与模型无关的框架适用于广泛的时空，包括观测推断的、量子引力启发的和规则的黑洞。 它提供了一个通用工具，用于探测它们的动力学起源，并能够从观测数据中重建底层的协变理论，包括引力波和黑洞阴影测量数据。 显示英文摘要

This work reveals a fundamental link between general covariance and Birkhoff's theorem. We extend Birkhoff's theorem from general relativity to a broad class of generally covariant gravity theories formulated in the Hamiltonian framework. Conversely, we show that each one-parameter family of static, spherically symmetric spacetimes determines a class of covariant theories, each of which has that family of spacetimes as its entire vacuum solution space. Our systematic and model-independent framework applies to a wide range of spacetimes, including observationally inferred, quantum-gravity-inspired, and regular black holes. It provides a universal tool for probing their dynamical origins and enables the reconstruction of the underlying covariant theories from observational data, including gravitational-wave and black-hole-shadow measurements.

[9] arXiv:2112.01490 [中文pdf, pdf, html, 其他]

标题： 经典相对论的随机量化 通过里奇流 显示英文标题

标题： Stochastic Quantization of General Relativity à la Ricci-Flow

Tausif Parvez, S. Shankaranarayanan (IIT Bombay)

评论： 16页；所有部分均已修订

主题： 广义相对论与量子宇宙学 (gr-qc) ; 高能物理 - 理论 (hep-th)

我们遵循一种新的路径来定义随机量化（SQ），这是Parisi和Wu首次提出的，该路径产生爱因斯坦方程的动作泛函。 基于Rumpf提出的 Ricci-Flow 方程与 SQ Langevin 方程之间的功能相似性，我们提出了一种新方法，其特征是乘法噪声和随机时间，在平衡极限下收敛于空间类叶的适当时间，其中量具有恒定的平均值。 我们使用Arnowitt-Deser-Misner (ADM) 变量及其共轭哈密顿动量来表达起始方程组。 这种选择有助于理解新推导出的方程，这些方程是经典理论微分同胚不变性的破坏，而在稳态下则平均保持不变。 我们评论了 Ricci 流方程的物理解释，并论证了它们如何以几何方式自然地为引力理论提供重整化群方程。 在一般情况下，与位移向量相关的方程给出带有随机源的纳维-斯托克斯方程。 此外，我们证明了在远离施瓦茨希尔德黑洞视界的情况下，度规张量分量的涨落受 Ricci 流的影响，遵循 Kardar-Parisi-Zhang 方程，其概率分布可以产生间歇统计。 最后，我们评论了这一新场景在宇宙学常数上的可能应用，认为 Ricci 流可能作为度规张量量子涨落尺度依赖性的宏观效应，提供解决哈勃张力的方案。 显示英文摘要

We follow a new pathway to the definition of the Stochastic Quantization (SQ), first proposed by Parisi and Wu, of the action functional yielding the Einstein equations. Hinging on the functional similarities between the Ricci-Flow equation and the SQ Langevin equations proposed by Rumpf, we push forward a novel approach characterized by a multiplicative noise and a stochastic time that converges to the proper time of a space-like foliation in the equilibrium limit, where quantities have constant averages. We express the starting system of equations using the Arnowitt-Deser-Misner (ADM) variables and their conjugated Hamiltonian momenta. Such a choice is instrumental in understanding the newly derived equations in terms of the breakdown of the diffeomorphism invariance of the classical theory, which instead will hold on average at the steady state. We comment on the physical interpretation of the Ricci flow equations, and argue how they can naturally provide, in a geometrical way, the renormalization group equation for gravity theories. In the general setting, the equation associated to the shift vector yields the Navier-Stokes equation with a stochastic source. Moreover, we show that the fluctuations of the metric tensor components around the equilibrium configurations, far away from the horizon of a Schwarzschild black hole, are forced by the Ricci flow to follow the Kardar-Parisi-Zhang equation, whose probabilistic distribution can yield an intermittent statistics. We finally comment on the possible applications of this novel scenario to the cosmological constant, arguing that the Ricci flow may provide a solution to the Hubble tension, as a macroscopic effect of scale dependence of the quantum fluctuations of the metric tensor.

[10] arXiv:2509.15487 [中文pdf, pdf, html, 其他]

标题： DiskMINT：具有径向变化气体和尘埃的自洽热化学盘模型——应用于IM Lup的高质量、CO丰富的盘 显示英文标题

标题： DiskMINT: Self-Consistent Thermochemical Disk Models with Radially Varying Gas and Dust -- Application to the Massive, CO-Rich Disk of IM Lup

Susobhan Mandal, S. Shankaranarayanan

评论： 已接受发表于ApJ。25页，15图。此更新版本更正了表5以及附录A和B中的拼写错误。

主题： 地球与行星天体物理学 (astro-ph.EP)

围绕年轻恒星的盘是行星的诞生地，其气体和尘埃质量的空间分布对于理解行星形成的位置和类型至关重要。 我们使用DiskMINT构建了自洽的热化学盘模型，该模型扩展了其初始框架，以允许气体和尘埃分布的空间解耦。 DiskMINT基于与尘埃颗粒的热平衡计算气体温度，求解垂直方向上的气体静力平衡，并包括CO化学的关键过程，特别是选择性光致离解以及与CO/CO$_2$冰的冻结-转化过程。 我们将DiskMINT应用于研究IM Lup盘，这是一个大质量盘，但根据早期的热化学模型推断其CO耗竭程度高达100。 通过拟合多波长SED以及毫米连续谱，${\rm C^{18}O}$径向发射轮廓，我们找到了$0.02-0.08\,{\rm M_\odot}$的气体盘质量，这些结果在误差范围内与动力学质量一致。 我们进一步比较了尘埃和气体的表面密度，发现外盘以漂移为主，尘埃与气体质量比约为0.01-0.02，这可能不足以满足流不稳定性发生的条件。 我们的结果表明，当用自洽的热化学模型进行解释时，${\rm C^{18}O}$单独可以作为总气体质量和其径向分布的可靠示踪物。 这种方法使得在缺乏动力学约束的低质量盘以及稀有物种如${\rm N_2H^+}$太弱而无法检测的较暗系统中，能够进行气体质量估算。 显示英文摘要

Disks around young stars are the birthplaces of planets, and the spatial distribution of their gas and dust masses is critical for understanding where and what types of planets can form. We present self-consistent thermochemical disk models built with DiskMINT, which extends its initial framework to allow for spatially decoupled gas and dust distributions. DiskMINT calculates the gas temperature based on thermal equilibrium with dust grains, solves vertical gas hydrostatic equilibrium, and includes key processes for the CO chemistry, specifically selective photodissociation, and freeze-out with conversion CO/CO$_2$ ice. We apply DiskMINT to study the IM Lup disk, a large massive disk, yet with an inferred CO depletion of up to 100 based on earlier thermochemical models. By fitting the multi-wavelength SED along with the millimeter continuum, ${\rm C^{18}O}$ radial emission profiles, we find $0.02-0.08\,{\rm M_\odot}$ for the gas disk mass, which are consistent with the dynamical-based mass within the uncertainties. We further compare the derived surface densities for dust and gas and find that the outer disk is drift-dominated, with a dust-to-gas mass ratio of approximately 0.01-0.02, which is likely insufficient to meet the conditions for the streaming instability to occur. Our results suggest that when interpreted with self-consistent thermochemical models, ${\rm C^{18}O}$ alone can serve as a reliable tracer of both the total gas mass and its radial distribution. This approach enables gas mass estimates in lower-mass disks, where dynamical constraints are not available, and in fainter systems where rare species like ${\rm N_2H^+}$ are too weak to detect.

[11] arXiv:2509.18188 [中文pdf, pdf, html, 其他]

标题： 关于在宇称破坏电动力学中弱能量条件违背的可行性 显示英文标题

标题： On the Viability of Weak Energy Condition Violation in Parity-Violating Electrodynamics

Chao Zhang, Tao Zhu

主题： 广义相对论与量子宇宙学 (gr-qc)

反常时空通常需要违反弱能量条件（WEC），而用现实物质实现这一点是困难的。 我们通过在有效场论（EFT）中添加一个单一的八维、宇称破坏性算符，该算符与\((F_{αβ}F^{αβ})(F_{γδ}\tilde F^{γδ})\)成正比，探索了一种保守的WEC违反方法，该算符被加入到麦克斯韦作用量中。 我们推导出修改后的爱因斯坦方程和麦克斯韦方程，并发现电磁应力-能量张量乘以一个与背景相关的因子\(Ω=1+ζ\mathcal P\)，其中\(\mathcal P\propto\vec E\cdot\vec B\)。 这在原则上允许当电场和磁场充分对齐时出现WEC违反（\(Ω<0\)）。 从现象学角度看，同一个算符会引发真空双折射。 通过将其预测效应与实验室（PVLAS）和天体物理（磁星X射线偏振）数据进行比较，我们对耦合常数\(ζ\)设定了严格的限制。 这些限制表明，WEC违反的阈值所需的场强远远超出任何可能的天体物理值，并接近EFT的失效尺度。 我们还构建了一个在\(Ω=0\)阈值下的精确平空间解。 我们得出结论，在这种简单的电动力学扩展中，负的有效能量密度在数学上是可能的，但在物理上无法达到。 显示英文摘要

Exotic spacetimes often require violations of the weak energy condition (WEC), a feat that is difficult to achieve with realistic matter. We explore a conservative route to WEC violation within an effective field theory (EFT) by adding a single dimension-eight, parity-violating operator, proportional to \((F_{αβ}F^{αβ})(F_{γδ}\tilde F^{γδ})\), to the Maxwell action. We derive the modified Einstein and Maxwell equations and find that the electromagnetic stress--energy tensor is multiplied by a background-dependent factor \(Ω=1+ζ\mathcal P\), where \(\mathcal P\propto\vec E\cdot\vec B\). This allows, in principle, for WEC violation (\(Ω<0\)) when electric and magnetic fields are sufficiently aligned. Phenomenologically, the same operator induces vacuum birefringence. By comparing its predicted effect to laboratory (PVLAS) and astrophysical (magnetar X-ray polarimetry) data, we place stringent constraints on the coupling \(ζ\). These constraints reveal that the threshold for WEC violation requires field strengths many orders of magnitude beyond any plausible astrophysical values and close to the EFT's breakdown scale. We also construct an exact flat-space solution at the \(Ω=0\) threshold. We conclude that within this simple extension of electrodynamics, negative effective energy densities are mathematically possible but physically unreachable.

[12] arXiv:2508.18491 [中文pdf, pdf, 其他]

标题： 轴子冷却对超新星轴子直接探测的影响 显示英文标题

标题： Impacts of axion cooling on the direct detection of supernova axions

Manuel Gonzalez-Espinoza, Ramón Herrera, Giovanni Otalora, Carlos Ríos, Carlos Rodriguez-Benites

评论： 17页，6图，2表，已接受发表于JCAP

主题： 高能天体物理现象 (astro-ph.HE) ; 宇宙学与非星系天体物理学 (astro-ph.CO) ; 高能物理 - 现象学 (hep-ph)

核心坍缩超新星提供了一个独特的机会来探测轴子，因为它们可以是这些粒子的丰富来源。最近有提议认为，如果超新星事件出现在几百秒差距内，轴子太阳望远镜可以用于直接搜索超新星轴子。然而，超新星轴子的事件数量仅在后处理框架内进行了估计。在本研究中，我们对一个9.6M_sun恒星进行了长期超新星模拟，并结合轴子辐射，以重新评估由太阳望远镜检测到的轴子事件数量。我们发现，由轴子辐射引起的额外冷却可以显著降低原中子星的温度。因此，与通过后处理得到的结果相比，轴子光度和因此轴子事件数量都减少了。我们的结果表明，轴子辐射的非线性反馈是预测轴子可探测性的关键因素，并强调了需要在各种前身星模型中进行系统模拟研究。 显示英文摘要

Core-collapse supernovae provide a unique opportunity to probe axions because they can be a copious source of the particles. It has recently been proposed that axion helioscopes can be used for the direct search for supernova axions if a supernova event appears within a few hundred parsecs. However, the event number of supernova axions has been estimated only within the post-process framework. In this study, we perform long-term supernova simulations for a 9.6M_sun star coupled with the axion emission to reevaluate the event number of axions detected by the helioscopes. We find that the additional cooling induced by the axion emission can significantly decrease the temperature in the proto-neutron star. As a result, the axion luminosity and hence the axion event number are reduced, compared with the result obtained through post-processing. Our result indicates that the nonlinear feedback of the axion emission is an essential factor to predict the axion detectability, and underscores the need for systematic simulation studies across various progenitor models.

[13] arXiv:2508.13999 [中文pdf, pdf, html, 其他]

标题： 多波长对看似不重复的FRB 20250316A的观测 显示英文标题

标题： Multiwavelength Observations of the Apparently Non-repeating FRB 20250316A

Antonio De Felice, Shinji Tsujikawa

评论： 已接受发表于《天体物理学杂志》

主题： 高能天体物理现象 (astro-ph.HE)

快速射电暴（FRBs）的物理起源仍然不确定。尽管已经进行了广泛的多波段观测，只有银河系内的FRB~20200428D与磁星SGR J1935+2154的X射线爆发有关。在这里，我们介绍了附近明亮的FRB~20250316A的多波段后续观测，包括五百米口径球面射电望远镜（FAST）、爱因斯坦探针（EP）X射线任务、钱德拉X射线天文台、宽场巡天望远镜（WFST）和空间可变天体监测/可见光望远镜（SVOM/VT）。13.08小时的FAST后续活动未检测到脉冲，要求能量分布比已知的重复FRBs更平缓，表明这次爆发可能是一次性事件。一次及时的EP后续观测和总计$>$100 ks的多历元观测活动导致在它的后续X射线望远镜（FXT，$10^{\prime\prime}$）的角度分辨率内检测到了一个X射线源。随后的钱德拉观测显示该源偏离FRB位置$7^{\prime\prime}$，并在FRB位置建立了0.5-10 keV通量上限$7.6\times 10^{-15}$ $\rm erg\,cm^{-2}\,s^{-1}$ ，对应于宿主星系NGC~4141的40 Mpc距离下的$\sim 10^{39}$ $\rm erg\,s^{-1}$ 。这些结果设定了非重复FRBX射线辐射最严格的限制之一，不利于超亮X射线源（ULXs）作为明显一次性FRBs的对应体，并提供了对余辉模型的关键见解。我们的研究表明，对FRB及其潜在X射线对应体进行角秒级定位对于探索FRB的X射线对应体至关重要。 显示英文摘要

The physical origin of fast radio bursts (FRBs) remains uncertain. Although multiwavelength observations have been widely conducted, only Galactic FRB~20200428D is associated with an X-ray burst from the magnetar SGR J1935+2154. Here, we present multiwavelength follow-up observations of the nearby bright FRB~20250316A, including the Five-hundred-meter Aperture Spherical radio Telescope (FAST), Einstein Probe (EP) X-ray mission, Chandra X-ray Observatory, Wide Field Survey Telescope (WFST) and Space Variable Object Monitor/Visible Telescope (SVOM/VT). The 13.08-hour FAST follow-up campaign without pulse detection requires an energy distribution flatter than those of well-known repeating FRBs, suggesting that this burst is likely a one-off event. A prompt EP follow-up and multi-epoch observational campaign totaling $>$ 100 ks led to the detection of an X-ray source within the angular resolution of its Follow-up X-ray Telescope (FXT, $10^{\prime\prime}$). A subsequent Chandra observation revealed this source to be offset by $7^{\prime\prime}$ from the FRB position, and established a 0.5-10 keV flux upper limit of $7.6\times 10^{-15}$ $\rm erg\,cm^{-2}\,s^{-1}$ at the FRB position, corresponding to $\sim 10^{39}$ $\rm erg\,s^{-1}$ at the 40 Mpc distance of the host galaxy NGC~4141. These results set one of the most stringent limits on X-ray emission from a non-repeating FRB, disfavoring ultra-luminous X-ray sources (ULXs) as counterparts of apparently one-off FRBs and offering critical insights into afterglow models. Our study suggests that an arcsecond localization of both the FRB and its potential X-ray counterpart is essential for exploring the X-ray counterpart of an FRB.

[14] arXiv:2511.13995 [中文pdf, pdf, html, 其他]

标题： SdS测地线的相空间以及利用宇宙学视界观测黑洞 显示英文标题

标题： Phase Space of SdS Geodesics and using the Cosmological Horizon to Observe a Black Hole

Moritz Reintjes, Ruochen Xia

评论： 22页，3图

主题： 广义相对论与量子宇宙学 (gr-qc) ; 高能物理 - 理论 (hep-th)

从黑洞视界附近传播到外部世界的光会经历高度的红移。 在发射体穿过视界的极限情况下，红移变为无限大。 从这个意义上说，靠近视界区域是不可观测的，因为发射的能量会低于某些可检测的阈值。 然而，在施瓦茨希尔德-德西特（SdS）时空中，由于正的宇宙学常数存在，还有一个第二层的宇宙学视界。 精心放置的观察者可以利用这个视界带来的蓝移效应。 从黑洞附近发出的信号频率可以被向上转移至可观测的值。 这种效应针对各种加速和测地线观察者进行了计算。 对SdS中径向和圆轨道的分析是本文的关键组成部分。 我们发现，在SdS测地线参数空间中存在一个“波峰”形状的临界曲线，曲线之下有三个圆轨道，曲线上有两个轨道，其他地方只有一个。 研究发现，观察落入黑洞的发射体发出的光子的最佳策略是接收者靠近宇宙学视界，并且也朝向黑洞移动。 对于从最小的圆轨道发出并被最大的圆轨道接收的光子，非零的宇宙学常数使观测效果增强了一个因子，该因子从零变化到三。 显示英文摘要

Light propagating from near a black hole horizon to the outside world is highly redshifted. In the limit that the emitter passes through the horizon, the redshift becomes infinite. In this sense the near horizon region is unobservable, as emission energies fall below some detectability bound. However, in Schwarzschild de Sitter (SdS) spacetime there is a second, cosmological, horizon due to the positive cosmological constant. Judiciously placed observers can take advantage of the blueshift due to this horizon. The frequency of signals emitted from near the black hole can be shifted back upward to an observable value. This effect is computed for a variety of accelerated and geodesic observers. An analysis of radial and circular geodesics in SdS is a key component of the paper. We find a ``cresting-wave" shaped critical curve in the SdS-geodesic parameter space such that under the curve there are three circular orbits, on the curve there are two orbits, and elsewhere there is one. It is found that the best strategy for observing photons from an emitter falling into the black hole is for the receiver to be near the cosmological horizon and also moving towards the black hole. For photons emitted from the smallest circular orbit and received at the largest circular orbit, the nonzero cosmological constant enhances observations by a factor that varies from zero to three.

[15] arXiv:2511.13835 [中文pdf, pdf, html, 其他]

标题： 从其探测极限重建引力波波形 显示英文标题

标题： Reconstructing the Gravitational Waveform from Its Probe Limit

V. A. Kshirsagar, A. S. Agrawal, S. A. Kadam, Vishwajeet S. Goswami

评论： 28页，1图

主题： 高能物理 - 理论 (hep-th) ; 广义相对论与量子宇宙学 (gr-qc)

二进制系统中的引力可观测量在后闵可夫斯基（PM）区域中用适当的运动学变量表示时，表现出与两个散射物体的质量$m_1$,$m_2$的简单多项式依赖关系。 我们指出，这一特性结合粒子交换对称性，可以从它们的探测器极限$m_1 \gg m_2$重建主导和次主导的PM波形。 作为应用，聚焦于它们在小速度或后牛顿（PN）区域中的重新展开，我们计算了探测器极限波形直到10PN，然后利用这一观察结果，从它们推导出中心质量系中任意质量的波形直到5PN。 为此，我们同时采用了基于振幅的波形积分表达式和尾部公式。 这种综合方法大大简化了完整次主导PM波形的PN展开。 显示英文摘要

Gravitational observables for binary systems exhibit a simple polynomial dependence on the masses $m_1$, $m_2$ of the two scattering objects when they are written in terms of the appropriate kinematic variables in the post-Minkowskian (PM) regime. We point out that this property, combined with particle interchange symmetry, allows one to reconstruct the leading and subleading PM waveforms from their probe limit, $m_1 \gg m_2$. As an application, focusing on their re-expansion in the small-velocity or post-Newtonian (PN) regime, we calculate the probe-limit waveforms up to 10PN, and then exploit this observation to deduce from them the waveforms for generic masses in the center-of-mass frame up to 5PN. To this end, we employ both the amplitude-based waveform integrands and the tail formula. This combined approach simplifies substantially the PN expansion of the full subleading PM waveform.

[16] arXiv:2511.14008 [中文pdf, pdf, html, 其他]

标题： 潮汐撕裂事件中由于盘不稳定性驱动的喷流碰撞产生的延迟射电辐射 显示英文标题

标题： Delayed radio emission in tidal disruption events from collisions of outflows driven by disk instabilities

Avijit Chowdhury, Gargi Sen, Sayan Chakrabarti, Santabrata Das

评论： 提交至ApJ，欢迎提出意见！

主题： 高能天体物理现象 (astro-ph.HE)

延迟的射电辐射已被认为与越来越多的潮汐撕裂事件（TDEs）有关。 对于许多事件，射电同步加速器辐射被推断起源于缓慢相对论性喷流的相互作用，这些喷流在TDE光学峰值后$\sim 100$--$1000$天延迟发射。 这些喷流的机制仍不确定，但可能与从TDE形成的吸积盘中的不稳定性或状态转变有关。 我们模拟由潮汐撕裂事件吸积盘的质量喷流（“耀斑”）碰撞产生的射电辐射，考虑两种连续的吸积盘耀斑彼此碰撞的情况，以及喷流与核周围介质（CNM）碰撞的情况。 对于$\sim 0.01$-$0.1 M_{\odot}$的耀斑质量，不同的中性介质密度以及喷射耀斑之间不同的时间间隔，我们证明由碰撞形成的激波在$\sim 10^{17}$cm 处的速度为$0.05c$-$0.3c$，并产生$L_ν \sim 10^{27}$-$10^{30}$erg s$^{-1}$ Hz$^{-1}$的强无线电辐射，这与观测事件的特性一致。 我们量化了典型峰值时间尺度和流量如何随模型的不同特性变化，并将我们的模型预测与一些具有延迟射电辐射的潮汐破坏事件进行了比较。 我们的模型成功地再现了多个事件的光变曲线和谱能量分布，支持了延迟喷流由盘不稳定性及状态转换引发，可以为潮汐破坏事件中的晚期射电辐射提供能量的观点。 显示英文摘要

Delayed radio emission has been associated with a growing proportion of tidal disruption events (TDEs). For many events, the radio synchrotron emission is inferred to originate from the interaction of mildly-relativistic outflows, launched with delay times of $\sim 100$--$1000$ d after the TDE optical peak. The mechanism behind these outflows remains uncertain, but may relate to instabilities or state transitions in the accretion disk formed from the TDE. We model the radio emission powered by the collision of mass outflows ("flares") from TDE accretion disks, considering scenarios in which two successive disk flares collide with each other, as well as collisions between the outflow and the circumnuclear medium (CNM). For flare masses of $\sim 0.01$-$0.1 M_{\odot}$, varied CNM densities, and different time intervals between ejected flares, we demonstrate that the shocks formed by the collisions have velocities $0.05c$-$0.3c$ at $\sim 10^{17}$ cm and power bright radio emission of $L_ν \sim 10^{27}$-$10^{30}$ erg s$^{-1}$ Hz$^{-1}$, consistent with the properties inferred for observed events. We quantify how the typical peak timescale and flux varies for different properties of our models, and compare our model predictions to a selection of TDEs with delayed radio emission. Our models successfully reproduce the light curves and SEDs for several events, supporting the idea that delayed outflows from disk instabilities and state transitions can power late-time radio emission in TDEs.

交叉提交 (展示 9 之 9 条目 )

[17] arXiv:2511.13814 (交叉列表自 gr-qc) [中文pdf, pdf, html, 其他]

标题： 扭曲渐近平坦时空 显示英文标题

标题： Twisting asymptotically-flat spacetimes

Feng-Li Lin, Sayid Mondal

评论： 57页

主题： 广义相对论与量子宇宙学 (gr-qc)

我们将Bondi形式推广以描述渐近平坦的时空，其中外向零测地线族不是超曲面正交的，即具有非零的扭曲。 在Newman-Penrose形式中，扭曲$\text{Im}(ρ)$由位于横向零双矢量$(m,\bar{m})$中的扭曲势源产生，而在度规形式中，该势来源于$g_{ra}\neq0$。 我们解释如何安排并求解此类广义线元的爱因斯坦方程，从而将Bondi层次结构扩展到具有非零扭曲的渐近平坦时空。 我们推导了所有与Bondi规范下渐近平坦时空相关的著名特性，如解空间、通量平衡定律、渐近对称性和变换规律的扭曲推广。 扭曲势自然地可以解释为Carroll联络，它作为额外的渐近对称性产生Carroll提升。 具有非零扭曲的Bondi规范的一个优势是，它允许以明显有限径向展开的方式写出代数特殊解，并且具有重复的主要零方向，使得$Ψ_0=Ψ_1=0$。 这尤其适用于Kerr-Taub-NUT解。 代数特殊解的渐近对称性也具有有限的径向展开，这使得可以非常直接地研究超平移的Schwarzschild解及其电荷。 我们预计这些结果将在代数特殊解的平坦全息理论的发展及其扰动的研究中找到应用。 我们还研究了具有非零宇宙常数的三维时空中的扭曲类似物，并发现了一个8维的解空间，该空间涵盖了并推广了文献中的现有结果。 显示英文摘要

We extend the Bondi formalism to describe asymptotically-flat spacetimes where the outgoing null geodesic congruence is not hypersurface-orthogonal, i.e. has a non-vanishing twist. In the Newman-Penrose formulation, the twist $\text{Im}(ρ)$ is sourced by a twist potential sitting in the transverse null dyad $(m,\bar{m})$, while in the metric formulation this potential arises from $g_{ra}\neq0$. We explain how to arrange and solve the Einstein equations for such generalized line elements, thereby providing an extension of the Bondi hierarchy to asymptotically-flat spacetimes with non-vanishing twist. We work out the twisting generalizations of all the well-known features pertaining to asymptotically-flat spacetimes in Bondi gauge, such as the solution space, the flux-balance laws, the asymptotic symmetries, and the transformation laws. The twist potential has a natural Carrollian interpretation as an Ehresmann connection, and gives rise to Carroll boosts as extra asymptotic symmetries. One of the advantages of the Bondi gauge with non-vanishing twist is that it allows to write algebraically special solutions in a manifestly finite radial expansion, and with a repeated principal null direction such that $Ψ_0=Ψ_1=0$. This is in particular the case for the Kerr-Taub-NUT solution. The asymptotic symmetries of algebraically special solutions also have a finite radial expansion, which enables to study the supertranslated Schwarzschild solution and its charges quite straightforwardly. We expect that these results will find applications in the development of flat holography for algebraically special solutions and in the study of their perturbations. We also study an analogue of the twist in three-dimensional spacetimes with non-vanishing cosmological constant, and find an 8-dimensional solution space which encompasses and generalizes the existing results in the literature.

[18] arXiv:2511.13817 (交叉列表自 astro-ph.GA) [中文pdf, pdf, html, 其他]

标题： 阿贝尔2597的深度钱德拉观测：气泡、激波、冷燃料供应和等离子体耗尽层 显示英文标题

标题： A Deep Chandra View of Abell 2597: Bubbles, Shocks, Cold Fueling, and a Plasma Depletion Layer

Yonatan Kahn, Michael Wentzel, Nicolás Yunes

评论： 被《天体物理学杂志》接受！31页，14图

主题： 星系的天体物理学 (astro-ph.GA) ; 高能天体物理现象 (astro-ph.HE)

为了研究活动星系核（AGN）反馈如何塑造团星系内介质（ICM）并为阿贝尔2597冷核心星系团中的黑洞吸积提供燃料，我们提供了深度（$\sim$600 ks）钱德拉X射线观测结果，并结合了档案中的GMRT射电和SINFONI近红外数据。 射电模式的AGN活动已膨胀出七个X射线空腔，并驱动了一个到三个潜在的弱冲击波（$M \sim 1.05-1.14$），延伸至$\sim 150$kpc，表明在$\sim 10^7$年时间尺度上发生了反复爆发。 我们还检测到一个狭窄的、$\sim$57 kpc的X射线表面亮度缺陷——一个潜在的等离子体耗尽层——可能由残留的搅动运动形成，这些运动增强了磁场和/或在团核心内移动了气体。 尽管AGN注入了$\sim 10^{44}$ erg s$^{-1}$的能量，与星系团的冷却光度相当，但辐射冷却仍持续在$\sim$15 M$_{\odot} $yr$^{-1}$，不断补充最亮星系核心的十亿太阳质量冷气体库。 维持这种活动水平需要持续的燃料供应，然而估计的Bondi吸积功率（$\sim 2 \times 10^{43}$ erg s$^{-1}$）比观测到的腔体功率低一个数量级，表明“热”气体燃料不足。 相反，档案中的ALMA观测结果继续支持一种混乱的冷吸积情景，其中湍流驱动的凝结以超过Bondi吸积的速率为AGN提供燃料，维持一个自我调节的反馈循环，反复塑造Abell 2597的核心。 显示英文摘要

To examine how AGN feedback shapes the intracluster medium (ICM) and fuels black hole accretion in the cool-core galaxy cluster Abell 2597, we present deep ($\sim$600 ks) Chandra X-ray observations complemented by archival GMRT radio and SINFONI near-infrared data. Radio-mode AGN activity has inflated seven X-ray cavities and driven one to three potential weak shocks ($M \sim 1.05-1.14$) extending to $\sim 150$ kpc, suggesting recurrent outbursts occurring on $\sim 10^7$ year timescales. We also detect a narrow, $\sim$57 kpc X-ray surface brightness deficit-a potential plasma depletion layer-likely shaped by residual sloshing motions that amplified magnetic fields and/or displaced gas within the cluster core. Although the AGN injects $\sim 10^{44}$ erg s$^{-1}$ of energy, comparable to the cluster's cooling luminosity, radiative cooling persists at $\sim$15 M$_{\odot} $yr$^{-1}$, replenishing the billion solar mass cold gas reservoir at the heart of the brightest cluster galaxy. Sustaining this level of activity requires a continuous fuel supply, yet the estimated Bondi accretion power ($\sim 2 \times 10^{43}$ erg s$^{-1}$) falls an order of magnitude short of the observed cavity power, suggesting that "hot" gas fueling is insufficient. Instead, archival ALMA observations continue to support a chaotic cold accretion scenario, where turbulence-driven condensation fuels the AGN at rates exceeding Bondi accretion, sustaining a self-regulated feedback cycle that repeatedly shapes the core of Abell 2597.

[19] arXiv:2511.14581 (交叉列表自 physics.flu-dyn) [中文pdf, pdf, html, 其他]

标题： 行星内部准地转湍流的亚网格尺度模型在线学习 显示英文标题

标题： Online learning of subgrid-scale models for quasi-geostrophic turbulence in planetary interiors

Bin Liu, Dong Lai

评论： 33页，11图，已提交发表于《流体力学杂志》

主题： 流体动力学 (physics.flu-dyn) ; 地球与行星天体物理学 (astro-ph.EP) ; 机器学习 (cs.LG)

将机器学习用于表示亚网格尺度（SGS）动力学在天气预报和气候建模中已经得到广泛认可。 最近的进展表明，通过“在线”端到端学习训练的SGS模型——其中在过滤方程上运行的动力学求解器参与训练——可以优于传统的基于物理的方法。 然而，大多数研究都集中在理想化的周期性域上，忽略了例如行星内部存在的机械边界。 为了解决这个问题，我们考虑在一个轴对称有界域中的二维准地转湍流，我们使用伪谱可微求解器进行建模，从而实现在线学习。 我们检查了三种配置，改变几何形状（在指数容器和球壳之间）和旋转速率。 流动由一个预定的解析强迫驱动，允许精确控制能量注入尺度并准确估计功率输入。 我们使用积分量和谱诊断方法，将在线训练的SGS模型与参考直接数值模拟进行比较以评估其准确性。 在所有配置中，我们证明了一个仅在单个周转时间数据上训练的SGS模型在至少比训练期长一百倍的积分过程中仍然稳定且准确。 此外，我们展示了该模型在时间尺度远超过训练持续时间的情况下再现缓慢过程的显著能力，例如球壳中的急流向内漂移。 这些结果表明，这为开发用于行星和恒星内部动力学（包括发电机过程）的SGS模型提供了一条有前景的路径。 显示英文摘要

The use of machine learning to represent subgrid-scale (SGS) dynamics is now well established in weather forecasting and climate modelling. Recent advances have demonstrated that SGS models trained via ``online'' end-to-end learning -- where the dynamical solver operating on the filtered equations participates in the training -- can outperform traditional physics-based approaches. Most studies, however, have focused on idealised periodic domains, neglecting the mechanical boundaries present e.g. in planetary interiors. To address this issue, we consider two-dimensional quasi-geostrophic turbulent flow in an axisymmetric bounded domain that we model using a pseudo-spectral differentiable solver, thereby enabling online learning. We examine three configurations, varying the geometry (between an exponential container and a spherical shell) and the rotation rate. Flow is driven by a prescribed analytical forcing, allowing for precise control over the energy injection scale and an exact estimate of the power input. We evaluate the accuracy of the online-trained SGS model against the reference direct numerical simulation using integral quantities and spectral diagnostics. In all configurations, we show that an SGS model trained on data spanning only one turnover time remains stable and accurate over integrations at least a hundred times longer than the training period. Moreover, we demonstrate the model's remarkable ability to reproduce slow processes occurring on time scales far exceeding the training duration, such as the inward drift of jets in the spherical shell. These results suggest a promising path towards developing SGS models for planetary and stellar interior dynamics, including dynamo processes.

[20] arXiv:2511.13803 (交叉列表自 gr-qc) [中文pdf, pdf, html, 其他]

标题： 共形与模糊引力的统一——研究其在低能下的行为及在引力波探测中的可能信号 显示英文标题

标题： Unification of Conformal and Fuzzy Gravities with Internal Interactions - study of their behaviour in low energies and possible signals in the detection of Gravitational Waves

Carlo Heissenberg, Rodolfo Russo

评论： 已接受发表于《对称性》

主题： 广义相对论与量子宇宙学 (gr-qc) ; 高能物理 - 理论 (hep-th)

规范与模糊引力与内部相互作用的统一基于以下两个事实。 第一个是弯曲流形的切空间群和流形本身不一定具有相同的维数。 第二个是此处考虑的两种引力理论都以规范理论的方式进行了表述。 在这里，我们想首先回顾引力的规范理论方法，特别是它们的微分同胚不变性。 然后我们将回顾规范理论框架下共形引力和非对易（模糊）引力的构建。 最后，基于四维切空间群的扩展，我们将展示这两种引力与内部相互作用的统一。 两种统一方案将进一步研究其在适当自发对称性破缺后的低能行为，以及相关宇宙弦在引力波中的可能信号。 显示英文摘要

The Unification of Conformal and Fuzzy gravities with Internal Interactions is based on the following two facts. The first is that the tangent group of a curved manifold and the manifold itself do not necessarily have the same dimensions. The second is that both gravitational theories considered here have been formulated in a gauge theoretic way. Here we would like to start by reviewing the gauge theoretic approach of gravities commenting in particular their diffeomorphism invariance. Then we will review the construction of the Conformal Gravity and the Noncommutative (Fuzzy) Gravity using the gauge theoretic framework. Finally based on an extension of the four-dimensional tangent group we will present the Unification of both Gravities with the Internal Interactions. Both unified schemes will be examined further concerning their behaviour in low energies after suitable spontaneous symmetry breakings as well as the possible signals of the related cosmic strings in the gravitational waves.

[21] arXiv:2511.13832 (交叉列表自 astro-ph.EP) [中文pdf, pdf, html, 其他]

标题： TOI-333b：围绕F7V恒星的海王星沙漠行星 显示英文标题

标题： TOI-333b: A Neptune Desert planet around a F7V star

V.K. Oikonomou

评论： 21页，19图，7表，已接受发表于A&A

主题： 地球与行星天体物理学 (astro-ph.EP) ; 太阳与恒星天体物理学 (astro-ph.SR)

观测表明，类似海王星的行星很少出现在周期长达约4天的类太阳恒星周围，这定义了所谓的海王星沙漠区域。 因此，在这一区域内发现的每个单独行星都具有很高的价值，可以提供关于这种种群如何形成和演化的详细见解。 在此，我们报告发现了TOI-333b，这是一个海王星沙漠行星，其质量、半径和整体密度分别为20.1 $\pm$ 2.4 M$_{\oplus}$，4.26 $\pm$ 0.11 R$_{\oplus}$，以及1.42 $\pm$ 0.21 \gccc ，分别。 该行星每3.78天围绕F7V恒星运行，其质量、半径和有效温度分别为1.2 $\pm$ 0.1 \msun ，1.10 $\pm$ 0.03 \rsun ，以及6241$^{+73}_{-62}$ K。 TOI-333b可能不到1 Gyr，这由6707.856 textup{~Å}附近的双线Li的存在及其与具有明确年龄的开放星团中Li丰度的比较所支持。 该行星预计仅拥有8.5$^{+10.9}_{-8.3}\%$ 的气体与核心质量比，用于H/He包层。 另一方面，辐射海洋世界模型预测20$^{+11}_{-10}\%$ H$_2$O质量分数，核心比例为35$^{+20}_{-23}\%$。 因此，我们预计TOI-333b内部成分可能以纯岩石成分为主，几乎没有H/He包层，或者是一个几乎具有相同质量分数的水的岩石世界。 最后，TOI-333b的质量和体积分别大于77$\%$和82$\%$的海王星沙漠伴星，而其宿主恒星是已知的海王星沙漠行星中最热的之一，使这个系统成为研究围绕热恒星这类行星演化的独特实验室。 显示英文摘要

Observations have shown that planets similar to Neptune are rarely found orbiting Sun-like stars with periods up to ~4 days, defining the so-called Neptune desert region. Therefore, the detection of each individual planet in this region holds a high value, providing detailed insights into how such a population came to form and evolve. Here we report the detection of TOI-333b, a Neptune desert planet with a mass, radius, and bulk density of 20.1 $\pm$ 2.4 M$_{\oplus}$, 4.26 $\pm$ 0.11 R$_{\oplus}$, and 1.42 $\pm$ 0.21 \gccc, respectively. The planet orbits a F7V star every 3.78 d, whose mass, radius and effective temperature are of 1.2 $\pm$ 0.1 \msun, 1.10 $\pm$ 0.03 \rsun, and 6241$^{+73}_{-62}$ K, respectively. TOI-333b is likely younger than 1 Gyr, which is supported by the presence of the doublet Li line around 6707.856 textup{~Å} and its comparison to Li abundances in open clusters with well constrained ages. The planet is expected to host only 8.5$^{+10.9}_{-8.3}\%$ gas-to-core mass ratio for a H/He envelope. On the other hand, irradiated ocean world models predict 20$^{+11}_{-10}\%$ H$_2$O mass fraction with a core fraction of 35$^{+20}_{-23}\%$. Therefore, we expect that TOI-333b internal composition may be dominated by a pure rocky composition with almost no H/He envelope, or a rocky world with almost equal mass fraction of water. Finally, TOI-333b is more massive and larger than 77$\%$ and 82$\%$ of its Neptune desert counterparts, respectively, while its host ranks among the hottest known for Neptune Desert planets, making this system a unique laboratory to study the evolution of such planets around hot stars.

[22] arXiv:2511.14697 (交叉列表自 astro-ph.GA) [中文pdf, pdf, html, 其他]

标题： 从Voronoi网格向自适应笛卡尔网格传输数据以实现自洽的自上而下恒星形成 显示英文标题

标题： Transferring Data from a Voronoi Mesh to an Adaptive Cartesian Grid in Pursuit of Self-consistent Top-down Star Formation

Yuchen Zhang, Yang Liu, Hongwei Yu, Puxun Wu

评论： 发表于ApJ。9页，6图

期刊参考： 天体物理期刊 994 69 (2025)

主题： 星系的天体物理学 (astro-ph.GA) ; 天体物理学的仪器与方法 (astro-ph.IM)

非结构化Voronoi网格模拟在星系尺度上模拟自引力气体动力学方面具有许多优势。自适应网格细化（AMR）可以是模拟恒星团形成和恒星反馈导致气体分散细节的强大工具。使用恒星团形成模拟包Torch从星系尺度缩放到局部尺度需要将模拟数据从一个尺度转移到另一个尺度。因此，我们介绍了VorAMR，一种新的计算工具，它将数据从非结构化Voronoi网格插值到AMR笛卡尔网格。VorAMR集成在Torch包中，该包将FLASH AMR磁流体动力学代码集成到天体物理多用途软件环境。VorAMR使用最近邻粒子方案将数据从AREPO模拟插值到FLASH AMR网格，然后可以在Torch包中演化，这是首次将数据从Voronoi网格传输到AMR笛卡尔网格。从一种数值表示插值到另一种会导致全局质量和能量守恒的几百分比误差，通过更高阶的Voronoi单元插值可以减少这种误差。我们表明，插值后的Torch模拟没有出现数值异常。初步的Torch模拟演化了3.22 Myr，并与同一时间段内的原始AREPO模拟进行了比较。我们观察到两种模拟中的恒星团形成分布相似。Torch模拟还产生了更紧凑的集群，并且恒星物质是AREPO的2.3倍，这可能是由于分辨率差异所致。 显示英文摘要

Unstructured Voronoi mesh simulations offer many advantages for simulating self-gravitating gas dynamics on galactic scales. Adaptive mesh refinement (AMR) can be a powerful tool for simulating the details of star cluster formation and gas dispersal by stellar feedback. Zooming in from galactic to local scales using the star cluster formation simulation package Torch requires transferring simulation data from one scale to the other. Therefore, we introduce VorAMR, a novel computational tool that interpolates data from an unstructured Voronoi mesh to an AMR Cartesian grid. VorAMR is integrated into the Torch package, which integrates the FLASH AMR magnetohydrodynamics code into the Astrophysical Multipurpose Software Environment. VorAMR interpolates data from an AREPO simulation to a FLASH AMR grid using a nearest-neighbor particle scheme, which can then be evolved within the Torch package, representing the first ever transfer of data from a Voronoi mesh to an AMR Cartesian grid. Interpolation from one numerical representation to another results in an error of a few percent in global mass and energy conservation, which could be reduced with higher-order interpolation of the Voronoi cells. We show that the postinterpolation Torch simulation evolves without numerical abnormalities. A preliminary Torch simulation is evolved for 3.22 Myr and compared to the original AREPO simulation over the same time period. We observe similarly distributed star cluster formation between the two simulations. More compact clusters are produced in the Torch simulation as well as 2.3 times as much stellar material as in AREPO, likely due to the differences in resolution.

[23] arXiv:2511.14645 (交叉列表自 astro-ph.IM) [中文pdf, pdf, html, 其他]

标题： 对系外行星直接成像社区的社会人口学研究 II 显示英文标题

标题： A socio-demographic study of the exoplanet direct imaging community II

Pradosh Keshav MV, NS Kavya, Kenath Arun

评论： 22页，8图

期刊参考： BAAS 2025

主题： 天体物理学的仪器与方法 (astro-ph.IM)

识别和解决天文学和天体物理学中的代表性不足、排斥和问题行为是至关重要的。 2019年，在Lyot精神会议上进行了一项调查，以评估系外行星和盘成像社区的社会人口统计学和幸福感。 本文介绍了在2022年莱顿举行的Lyot精神会议上进行的第二次调查的结果，旨在改进对社区的评估，扩展与多样性相关的问题，并监测自2019年以来各项指标的变化。 该调查发送给了所有参与者，收到了96份回复。 它衡量受访者在会议上的可见度，通过出版物和项目获得的认可，作为受害者或目击者经历的不尊重或不当行为，以及作为少数群体盟友的认同感。 这些方面根据职位、出国情况、性别、属于另一个代表性不足的群体（种族、残疾、性取向）以及是否有子女进行了分析。 显示英文摘要

Recognizing and addressing under-representation, exclusion, and problematic behavior within astronomy and astrophysics is crucial. In 2019, a survey was conducted at the Spirit of Lyot conference to evaluate the socio-demographics and well-being of the exoplanet and disk imaging community. This paper presents the results of a second survey, conducted at the 2022 Spirit of Lyot conference in Leiden, aiming to improve the evaluation of the community, expand diversity-related questions, and monitor the evolution of metrics since 2019. Sent to all participants, the survey received 96 responses. It measures respondents' visibility at conferences, recognition through publications and projects, experiences of disrespect or inappropriate behaviors as victims or witnesses, and identification as allies of minorities. These aspects were analyzed with respect to job position, expatriation, gender, belonging to another under-represented group (ethnicity, disability, sexual orientation), and parenthood.

[24] arXiv:2511.12622 (交叉列表自 hep-th) [中文pdf, pdf, html, 其他]

标题： IR/UV混合来自标量场中的高阶相互作用 显示英文标题

标题： IR/UV mixing from higher-order interactions in a Scalar Field

Sourav Ballav, Chi-Hsien Tai, Wen-Yu Wen

主题： 高能物理 - 理论 (hep-th) ; 广义相对论与量子宇宙学 (gr-qc)

众所周知，当用截断进行正则化时，计算得到的宇宙学常数与测量值相差极大。 这些计算是基于通常设定在普朗克尺度的波矢量截断。 此外，温伯格的不可能定理表明，在存在平移不变性的前提下，局部量子场论无法在不精细调节的情况下产生零宇宙学常数。 已经构建了多种非局域理论，从对爱因斯坦方程的修改开始，以“抵消”宇宙学常数项。 还有一种由科尔曼提出的著名理论，该理论假设可以计算通过虫洞连接的婴儿宇宙的概率分布函数，在某些假设下，该常数的最可能值为零。 本文从四维量子场论出发，通过将场限制在一个盒子中来破坏平移不变性，并添加了一个在计数幂次上为边缘的非线性、动量依赖项，在高能极限下，该项主导了二次项产生的动力学。 它立即产生了一个适用于该理论的波矢量截断方程——该方程让人联想到紫外/红外混合，对于宇宙大小的盒子来说，它有效地大幅降低了截断。 然而，正如将要展示的那样，对于常规粒子物理实验相关的盒子来说，波矢量截断要大得多，实际上就是普朗克尺度，因此与当前实验（包括卡西米尔效应）没有冲突。 我们考虑了这些附加项的几种可能性，并得出结论，只有一种与低截断有关。 我们还与最近的DESI结果建立了联系。 显示英文摘要

It is well known that the calculated cosmological constant, when regularized with a cutoff, differs hugely from the measured value. These calculations are made on the basis of a wave-vector cut-off that is usually set at the Planck scale. Further, Weinberg's no-go theorem indicates that in the presence of translational invariance, local quantum field theories cannot produce a zero cosmological constant without fine-tuning. Various non-local theories have been constructed, starting from modifications to Einstein's equations, in order to `cancel' away the cosmological constant term. There is also a well-known theory, due to Coleman, that assumes one can compute a probability distribution function for baby universes connected by wormholes that has the most probable value of the constant to be zero under some assumptions. The current paper starts from a QFT in 4-dimensions, breaks translational invariance by confining the fields to a box and adds a marginal (in power-counting terms) non-linear, momentum-dependent term that dominates the dynamics produced by the quadratic terms in the high-energy limit. It immediately produces an equation for the wave-vector cutoff applicable to the theory - the equation is reminiscent of that from UV/IR mixing and it effectively lowers the cutoff massively for a box the size of the Universe. However, as will be shown, the wave-vector cutoff for a box relevant for regular particle physics experiments is much larger, in fact, the Planck scale, so there is no conflict with current experiments, including the Casimir effect. We consider several possibilities for these additional terms and conclude that only one is relevant to a low cut-off. We also make a connection to the recent DESI results.

[25] arXiv:2509.20970 (交叉列表自 astro-ph.HE) [中文pdf, pdf, html, 其他]

标题： 高能伽马射线和中微子来自太阳、木星和地球 显示英文标题

标题： High energy gamma rays and neutrinos from the Sun, Jupiter and Earth

Laura Iacconi, Sukannya Bhattacharya, Matteo Fasiello, David Wands

评论： 17页，增加了地球边缘的参考文献和费米-LAT结果，该版本将发表在《天体物理杂志》上

主题： 高能天体物理现象 (astro-ph.HE) ; 高能物理 - 现象学 (hep-ph)

宇宙射线到达天体的大气层会产生次级粒子的级联，这些粒子可能随后逃逸到太空中。 在这里，我们得到了由太阳、木星和地球发出的能量为$E>10$ GeV 的伽马射线和中微子通量。 我们表明，虽然太阳磁场会在太阳表面的所有点上诱导伽马射线通量，但行星的偶极磁场仅在非常边缘区域产生高能光子。 相比之下，中微子可以穿过这些天体并从其表面的任何点逸出。 这些天体的辐射超过了宇宙射线与星际介质相互作用产生的弥漫通量，并具有独特的光谱和伽马射线与中微子比率。 显示英文摘要

Cosmic rays reaching the atmosphere of an astrophysical object produce showers of secondary particles that may then escape into space. Here we obtain the flux of gamma rays and neutrinos of energy $E>10$ GeV emitted by the Sun, Jupiter and Earth. We show that, while the solar magnetic field induces a flux of gamma rays from all the points on the Sun's surface, the dipolar magnetic field in the planets implies high energy photons only from the very peripheral region. Neutrinos, in contrast, can cross these objects and emerge from any point on their surface. The emission from these astrophysical objects exceeds the diffuse flux from cosmic ray interactions with the interstellar medium and has a distinct spectrum and gamma ray to neutrino ratio.

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[26] arXiv:2511.03258 (替换) [中文pdf, pdf, html, 其他]

标题： 宇宙加速的粘性流体模型在FRW时空中的MCMC约束 显示英文标题

标题： Viscous Fluid Models of Cosmic Acceleration in FRW Spacetime Using MCMC Constraints

Matteo Lulli, Antonino Marciano, Xiaowen Shan

评论： 23页，11图

主题： 广义相对论与量子宇宙学 (gr-qc)

本研究结合理论进展与观测限制，探讨在(3+1)维时空框架下的弗里德曼-罗伯逊-沃尔克(FRW)模型中，体粘滞修正查普利金气体(MCG)的宇宙学意义。 我们提供了粘性和非粘性情况的解析解，指出了能量密度演化、哈勃参数动力学以及减速参数转换的变化。 体粘滞抑制了结构形成中的振荡，这是查普利金气体模型在高维空间中的一个众所周知的缺点，通过详尽的扰动分析得到了验证。 利用体粘滞系数和哈勃膨胀参数，这些参数由总压强和适当压强所包含，并通过能量动量守恒定律确定的时间依赖密度。 借助三个条件（$ξ= 0$，$ξ\neq0$，我们忽略体粘滞和查普利金气体的存在，即$A=0$和$ξ=0$）创建了三种不同的模型，其中哈勃参数是红移$z$的函数。 通过对这些模型应用MCMC方法，我们使用哈勃和BAO数据集进行了观测分析。 显示英文摘要

This study combines theoretical advancements with observational limitations to investigate the cosmological implications of a bulk viscous modified Chaplygin gas (MCG) in a Friedmann--Robertson--Walker (FRW) in (3+1) dimensional spacetime framework. We provide analytical solutions for both viscous and non-viscous cases, pointing out variations in the energy density evolution, the Hubble parameter dynamics, and the deceleration parameter transitions. Bulk viscosity suppresses oscillations in structure creation, a well-known drawback of Chaplygin gas models in larger dimensions, as shown by a thorough perturbation analysis. Using the bulk viscosity coefficient and Hubble expansion parameter, which are incorporated by the total pressure and the appropriate pressure and by using energy momentum conservation law determined time time-dependent density. With the help of three conditions ($ξ= 0$, $ξ\neq0$, and we neglect both bulk viscosity and presence of Chaplygin gas, i.e $A=0$ and $ξ=0$) created three different models as the Hubble parameter is a function of redshift $z$. By applying the MCMC method to these models, we have gone through observational analysis by using the Hubble and BAO datasets.

[27] arXiv:2511.14309 (替换) [中文pdf, pdf, html, 其他]

标题： 宇宙学动力学在$f(R,L_m,T)$改造引力中 显示英文标题

标题： Cosmological Dynamics in $f(R,L_m,T)$ Modified Gravity

Fawzi Aly, Mahmoud A. Mansour, Dejan Stojkovic

评论： 10页，3图

主题： 广义相对论与量子宇宙学 (gr-qc)

在本文中，我们研究宇宙的加速膨胀阶段，在$f(R,L_m,T)$引力理论的框架内，其中$R$、$L_m$和$T$分别表示里奇标量、物质拉格朗日量和能量-动量张量的迹。 我们关注由$f(R,L_m,T) = R - μL_m T - γ$定义的一种修改引力的具体形式，其中$μ$和$γ$是正常数。 物质部分由拉格朗日密度$L_m = -ρ$表征，其中$ρ$表示宇宙流体的能量密度。 我们通过相空间分析对模型进行了深入检查，使用动力系统技术全面评估了宇宙学解的演化。 结果通过相空间中的图形进行说明，包括临界点的特征以及在所提出的修改引力$f(R,L_m,T)$宇宙学框架内的稳定吸引子。 我们研究了宇宙从初始减速阶段到当前加速阶段的转变。 在适当初始条件下的方程状态行为和减速度参数已被研究。 显示英文摘要

In this paper, we investigate the accelerating phase of the Universe within the context of $f(R,L_m,T)$ gravity theory, where $R$, $L_m$, and $T$ represent the Ricci scalar, matter Lagrangian, and the trace of the energy-momentum tensor, respectively. We focus on a particular form of modified gravity defined by $f(R,L_m,T) = R - μL_m T - γ$, with $μ$ and $γ$ being positive constants. The matter sector is characterized by the Lagrangian density $L_m = -ρ$, where $ρ$ denotes the energy density of the cosmological fluid. We conduct an in-depth examination of the model using phase space analysis, thoroughly evaluating the evolution of cosmological solutions with dynamical system techniques. The results is illustrated through graphs in the phase space, the characteristics of critical points and the stable attractors within the proposed modified gravity $f(R,L_m,T)$ cosmological framework. We investigate the transition from the initial decelerating phase of the universe to its current accelerating phase. The behaviour of the EoS, deceleration parameter with the appropriate initial conditions have been investigated.

[28] arXiv:2511.14287 (替换) [中文pdf, pdf, html, 其他]

标题： 广义相对论中的静态恒星相变和广义的 Buchdahl 极限 显示英文标题

标题： Static Stellar Phase Transitions in General Relativity and a Generalized Buchdahl Limit

Cong Zhang, Zhoujian Cao

主题： 广义相对论与量子宇宙学 (gr-qc)

我们给出了静态球对称爱因斯坦-欧拉方程的第一种一般性构造，即托尔曼-奥本海默-沃尔科夫（TOV-）方程，允许指定的密度函数是不连续和非均匀的；这些解描述了广义相对论中的恒星相变。 通过在指定密度上识别一个新条件，得到了从边界到恒星中心的解的压强函数的有界性，这是对经典布赫达赫极限的一般化。 此外，我们引入了一个存在这种有界压强函数的新必要条件，在均匀密度状态的特殊情况下，该条件退化为对恒星质量-半径关系的经典布赫达赫极限。 我们给出了各种例子来研究由我们的新条件产生的恒星质量-半径关系。 显示英文摘要

We give the first general construction of solutions of the static spherically symmetric Einstein-Euler equations, the Tolman-Oppenheimer-Volkoff (TOV-)equation, with prescribed density functions allowed to be discontinuous and non-uniform; these solutions describe stellar phase transitions in General Relativity. Boundedness of the resulting pressure functions solving the TOV-equations, from the boundary down to the stellar center, is obtained by identifying a novel condition on the prescribed density, in generalization of the classical Buchdahl limit. Moreover, we introduce a new necessary condition for the existence of such bounded pressure functions, which in the special case of a uniform density state reduces to the classical Buchdahl limit on the stellar mass-radius relationship. We present various examples to study the stellar mass-radius relationships resulting from our new conditions.

[29] arXiv:2511.13848 (替换) [中文pdf, pdf, html, 其他]

标题： 引力原子光谱学 显示英文标题

标题： Gravitational Atom Spectroscopy

Matteo Luca Ruggiero, Davide Astesiano

主题： 广义相对论与量子宇宙学 (gr-qc) ; 高能物理 - 现象学 (hep-ph) ; 高能物理 - 理论 (hep-th)

我们的宇宙中的黑洞很少是真正孤立的，而是嵌入在等离子体或暗物质等天体物理环境中。 一个特别引人注目的可能性是，轻量标量场会在黑洞周围形成束缚态，产生被称为引力原子的扩展“云”。 当这些云变得足够致密时，时空将无法再用广义相对论的真空解来描述。 在这个范围内，可以构建准静态、球对称、自引力的引力原子配置。 在这里，我们通过计算其基本准正则模来探索这些系统的观测相关方面。 我们给出了轴对称模在时间和频率域中的完全相对论计算，发现相对于真空情况的频率偏移主要取决于引力原子的致密性。 对于足够致密的配置，这些偏移可能被当前或未来的引力波探测器检测到。 显示英文摘要

Black holes in our Universe are rarely truly isolated, being instead embedded in astrophysical environments such as plasma or dark matter. A particularly intriguing possibility is that light scalar fields form bound states around black holes, producing extended ''clouds'' known as gravitational atoms. When these clouds become sufficiently compact, the spacetime can no longer be described by a vacuum solution of General Relativity. In this regime, one can construct quasi-stationary, spherically symmetric, self-gravitating scalar gravitational-atom configurations. Here, we explore an observationally relevant aspect of these systems by computing their fundamental quasi-normal mode. We present a fully relativistic calculation of the axial modes in both the time and frequency domains, finding frequency shifts relative to the vacuum case that depends mostly on the compactness of the gravitational atom. For sufficiently compact configurations, these shifts may be detectable by current or future gravitational wave detectors.

[30] arXiv:2511.13842 (替换) [中文pdf, pdf, html, 其他]

标题： NUT型极端孤立视界 显示英文标题

标题： Extremal isolated horizons of the NUT type

Yong Song

评论： 28页，1图

主题： 广义相对论与量子宇宙学 (gr-qc) ; 高能物理 - 理论 (hep-th)

我们提供了一类新的轴对称极端孤立视界构造，该视界在二维球面上具有U(1)主纤维丛的结构。与之前的例子不同，假设零生成元与纤维丛横截。我们在视界处施加爱因斯坦方程，并显式推导出上述类别的极端视界的全部内在几何结构，包括一个二维球面度量和一个旋转1-形式。2-几何结构被证明等价于具有乘积拓扑的圆锥奇点视界的分类。然后将旋转和非旋转视界嵌入到Plebański-Demiański时空，这些时空自然地容纳这种类型的视界。此外，我们将我们的结果与之前获得的带有宇宙常数的爱因斯坦真空极端视界方程解以及具有横截纤维结构的Petrov D型方程解进行比较。 显示英文摘要

We provide a construction of a new class of axisymmetric extremal isolated horizons admitting a structure of U(1)-principal fiber bundle over a two-sphere. In contrast to the previous examples, the null generators are assumed to be transversal to the bundle fibers. We impose the Einstein equations at the horizon and explicitly derive all intrinsic geometries of the extremal horizon, consisting of a two-sphere metric and a rotation 1-form, in the above class. The 2-geometries turn out to be equivalent to the classification of conically singular horizons with product topology. Both the rotating and non-rotating horizons are then embedded in the Plebański-Demiański spacetimes, which naturally admit horizons of this type. Furthermore, we compare our results with previously obtained solutions to the Einstein vacuum extremal horizon equation with cosmological constant and the solution of Petrov type D equation with transversal bundle structure.

[31] arXiv:2511.13423 (替换) [中文pdf, pdf, html, 其他]

标题： 协同-曲率模型中的涌现谱几何 显示英文标题

标题： Emergent spectral geometry in the Coherence--Curvature Model

Alexandre Landry, Yassine Sekhmani, Sunil K Maurya, Akram Ali, Emmanuel N. Saridakis

评论： 21页，5张图表。代码和汇总数据可在Zenodo上找到（参见DOI）。https://doi.org/10.5281/zenodo.17606900

主题： 广义相对论与量子宇宙学 (gr-qc) ; 高能物理 - 理论 (hep-th)

我们研究了相干-曲率模型（CCM），这是一个由哈密顿量支配的连接图的动态集合，该哈密顿量耦合了代数连通性、Ollivier-Ricci曲率和边密度惩罚项。 使用连通模拟退火，我们生成低能图配置，并通过谱维数（ds）、豪斯多夫维数（dh）和平均距离来表征其出现的几何特性。 有限尺寸标度显示ds随着系统尺寸的增长而明显增加，而dh则增长较温和。 在探索的最大体积下，数据与ds ~ 4和dh ~ 3相容，这意味着ds > dh，并且谱维数和体积维数之间存在非平凡的层次结构。 我们还绘制了曲率耦合gamma和局域性耦合beta的依赖关系，并发现典型距离随小指数eta缓慢地呈现幂律增长。 因此，CCM提供了一个受控的数值实验室，在其中相干性、曲率和局域性的相互作用产生了有限维、类似分形的几何结构。 显示英文摘要

We investigate the Coherence--Curvature Model (CCM), a dynamical ensemble of connected graphs governed by a Hamiltonian that couples algebraic connectivity, Ollivier-Ricci curvature, and an edge-density penalty. Using connected simulated annealing we generate low-energy graph configurations and characterize their emergent geometry through the spectral dimension (ds), the Hausdorff dimension (dh), and the average distance. Finite-size scaling shows a clear growth of ds with system size, while dh increases more mildly. At the largest volumes explored the data are compatible with ds ~ 4 and dh ~ 3, implying ds > dh and a nontrivial hierarchy between spectral and volumetric notions of dimension. We also map the dependence on the curvature coupling gamma and the locality coupling beta, and we find a slow power-law growth of typical distances with a small exponent eta. The CCM therefore provides a controlled numerical laboratory in which the interplay of coherence, curvature, and locality yields finite-dimensional, fractal-like geometries.

[32] arXiv:2503.03305 (替换) [中文pdf, pdf, html, 其他]

标题： 湍流在确定星际介质相位中的作用及对恒星形成率的影响 显示英文标题

标题： The role of turbulence in setting the phase of the ISM and implications for the star formation rate

Lorenzo Iorio

评论： 19页，17图，发表于《天体物理学开放期刊》

主题： 星系的天体物理学 (astro-ph.GA)

在本工作中，我们探讨了恒星形成、湍流和多相星际介质热状态之间的联系。我们分析了一套分层箱模拟，这些模拟旨在模拟现实的星际介质，以探测类似于银河系中发现的环境。湍流通过恒星反馈和外部大尺度驱动力注入。我们发现，当增加外部驱动强度时，恒星形成可能被增强或减少，这取决于环境。当密度足够高或紫外线背景较弱时，温暖中性气体自然会过渡到冷相，导致冷中性介质（CNM）的比例约为30-40%。在这些条件下，过强的大尺度驱动会导致CNM比例略有减少，并增加热不稳定性气体的量。在这个区域内限制恒星形成的是由于额外的湍流支撑而减少了致密气体的比例。对于受到显著外部紫外线背景影响的低密度区域，冷却有效的高密度区域较少，我们发现恒星形成由冷气体的形成所调节。在这些情况下，湍流可以通过在激波中压缩气体并增加CNM比例来显著增强恒星形成：我们看到CNM的比例从几乎为零增加到高达15%。我们提供了一个模型来量化这种行为，并通过将标准星际介质冷却/加热模型与湍流产生的密度概率分布函数相结合来预测CNM比例。在低密度/外部加热和中间密度/反馈加热环境之间，恒星形成的主要限制过程的变化可以为观测到的肯尼特-施密特关系在柱密度约为9 \Msun pc$^{-2}$附近的断点提供一个自然解释。 显示英文摘要

In this work, we explore the link between star formation, turbulence and the thermal state of the multi-phase ISM. We analyse a suite of stratified box simulations modelling a realistic ISM that aims to probe environments similar to those found in the Milky Way. Turbulence is injected through stellar feedback and an external large-scale driving force. We find that star formation can be either boosted or reduced when increasing the external driving strength, depending on the environment. When the density is sufficiently high or the UV background weak, warm neutral gas naturally transitions to the cold phase, leading to high CNM fractions of around 30 -- 40\%. Under these conditions, excessive large-scale driving leads to a slight reduction of the CNM fraction and an increase in the amount of gas that is thermally unstable. What limits the star formation in this regime is a reduced fraction of dense gas due to additional turbulent support against collapse. For low density regions subject to significant external UV background, overdensities in which cooling is efficient are much rarer and we find that star formation is regulated by the formation of cold gas. In such cases, turbulence can significantly boost star formation by compressing gas in shocks and increasing the CNM fraction: we see an increase from almost no CNM to up to a fraction of 15 \%. We provide a model to quantify this behaviour and predict the CNM fraction by combining the standard ISM cooling/heating model with the density PDF generated by turbulence. The change in the dominant limiting process for star formation between low-density/externally heated and intermediate-density/feedback heated environments could provides a natural explanation for the observed break in the Kennicutt-Schmidt relation around column densities of 9\,\Msun\, pc$^{-2}$.

[33] arXiv:2511.14733 (替换) [中文pdf, pdf, html, 其他]

标题： 星光驱动的辐射流体动力学模型中原行星盘的膨胀楼梯几何结构 显示英文标题

标题： Starlight-driven flared-staircase geometry in radiation hydrodynamic models of protoplanetary disks

Rita Megale, Alejandro Cruz-Osorio, Giuseppe Ficarra, Mario Imbrogno, Claudio Meringolo, Leonardo Primavera, Luciano Rezzolla, Sergio Servidio

评论： 17页，16幅图，根据审稿人意见重新提交至A&A；摘要为arXiv提交而缩短

主题： 地球与行星天体物理学 (astro-ph.EP)

原行星盘在毫米连续谱和散射光中观测到各种次结构。 盘中的各种物理过程可能触发这些特征——其中一种之前已为被动盘理论化的现象是热波不稳定性——当盘的倾斜区域直接被照射时，可能会膨胀并在其后方投下阴影，导致盘变得不稳定。 这会表现为盘光学表面的明亮和黑暗环以及阶梯状结构。 我们提供了一个现实的辐射流体动力学模型，以测试辐射盘中热波不稳定性的影响范围。 我们进行了全局轴对称二维静力和动态模拟，包括频率依赖的射线追踪辐射传输和通量限制扩散（FLD）。 我们发现，由恒星光线驱动的阴影在光学厚、冷却缓慢的盘中最显著，这由我们的模型所展示，这些模型具有高表面密度和亚微米颗粒的尘气比为0.01。 我们恢复了在静力极限下热波形成并向内传播的现象。 相比之下，我们的流体动力学模型显示在30天文单位内出现隆起和阴影，并在几个辐射扩散时间尺度上收敛到准稳态——表明存在寿命较长的阶梯结构。 我们发现，现有的热压隆起可以产生并增强这种效应，在下游形成二次阴影。 具有自洽尘埃沉降的静力模型则显示出一个过热的尘埃辐射吸收表面，温度分布径向平滑，没有阶梯。 我们得出结论，可以通过通量限制扩散在辐射流体动力学模拟中恢复辐射原行星盘中的热诱导的倾斜-阶梯结构。 我们强调了对尘埃动力学进行一致建模的重要性，以解释由恒星光线驱动的阴影。 显示英文摘要

Protoplanetary disks observed in millimeter continuum and scattered light show a variety of substructures. Various physical processes in the disk could trigger such features -- one of which that has been previously theorized for passive disks is the thermal wave instability -- the flared disk may become unstable as directly illuminated regions puff up and cast shadows behind them. This would manifest as bright and dark rings, and a staircase-like structure in the disk optical surface. We provide a realistic radiation hydrodynamic model to test the limits of the thermal wave instability in irradiated disks. We carry out global axisymmetric 2D hydrostatic and dynamic simulations including radiation transport with frequency-dependent ray-traced irradiation and flux-limited diffusion (FLD). We found that starlight-driven shadows are most prominent in optically thick, slow cooling disks, shown by our models with high surface densities and dust-to-gas ratios of sub-micron grains of 0.01. We recover that thermal waves form and propagate inwards in the hydrostatic limit. In contrast, our hydrodynamic models show bumps and shadows within 30 au that converge to a quasi-steady state on several radiative diffusion timescales -- indicating a long-lived staircase structure. We find that existing thermal pressure bumps could produce and enhance this effect, forming secondary shadowing downstream. Hydrostatic models with self-consistent dust settling instead show a superheated dust irradiation absorption surface with a radially smooth temperature profile without staircases. We conclude that one can recover thermally induced flared-staircase structures in radiation hydrodynamic simulations of irradiated protoplanetary disks using flux-limited diffusion. We highlight the importance of modeling dust dynamics consistently to explain starlight-driven shadows.

[34] arXiv:2511.14047 (替换) [中文pdf, pdf, html, 其他]

标题： 精确的非奇异黑洞来自作为原始暗物质的幻影DBI场 显示英文标题

标题： Exact, non-singular black holes from a phantom DBI Field as primordial dark matter

Tao Huang

评论： 29页，3张图，欢迎提出意见

主题： 广义相对论与量子宇宙学 (gr-qc) ; 高能物理 - 现象学 (hep-ph) ; 高能物理 - 理论 (hep-th)

我们提出了广义相对论中第一个精确的、非奇异的黑洞解，该解由狄拉克-伯恩-英菲尔德（DBI）标量场产生。 关键的是，该解仅由DBI作用量的鬼魂分支支持，动态地将中心奇点替换为一个规则的核心。 该解是渐近平坦的，具有非平凡的标量毛发，并将中心奇点替换为一个规则的2球面。 奇点解析的机制是一种动态的动能刚度——类似于非牛顿流体中的剪切增稠——这也解释了规避经典无毛定理的原因。 我们表明这些黑洞蒸发成一个稳定、非奇异、极端普朗克尺度的遗迹。 这提供了一种稳健的机制来规避标准蒸发约束，为轻质原初黑洞构成暗物质开辟了一个以前被禁止的大质量窗口。 该模型可通过其标量毛发产生的独特引力波特征进行测试。 显示英文摘要

We present the first exact, non-singular black hole solution in General Relativity sourced by a Dirac-Born-Infeld (DBI) scalar field. Crucially, the solution is exclusively supported by the phantom branch of the DBI action, dynamically replacing the central singularity with a regular core. The solution is asymptotically flat, possesses non-trivial scalar hair, and replaces the central singularity with a regular 2-sphere. The mechanism for singularity resolution is a dynamical kinetic stiffness -- analogous to shear thickening in non-Newtonian fluids -- which also explains the evasion of classical no-hair theorems. We show these black holes evaporate to a stable, non-singular, extremal Planck-scale relic. This provides a robust mechanism to evade standard evaporation constraints, opening a vast, previously forbidden mass window for light Primordial Black Holes to constitute dark matter. The model is testable via distinctive gravitational-wave signatures from its scalar hair.

[35] arXiv:2510.23584 (替换) [中文pdf, pdf, html, 其他]

标题： 牛顿引力能产生量子纠缠吗？ 显示英文标题

标题： Can Newtonian Gravity Produce Quantum Entanglement?

Bernardo Araneda, Maciej Dunajski

评论： 6页，1图，v2。由于澄清了一些细微问题，标题已更改，现在结论与GIE一致

主题： 高能物理 - 理论 (hep-th)

在本说明中，我们基于源理论考虑物质-引力相互作用的具体场景，以澄清关于引力诱导纠缠（GIE）协议的问题，该协议认为通过纯引力效应产生的量子纠缠的检测是量子引力的探测器。 因此，GIE协议意味着经典引力不能产生或媒介量子纠缠，而最近的一篇论文\cite{Aziz:2025ypo}显示了相反的结果。 在物质-引力相互作用的三种场景中，包括小超空间、半经典引力和随机引力方法，我们的结果与GIE协议及其含义一致。 更准确地说，我们表明，通过牛顿引力相互作用的介观量子物体，只有当由量子物体产生的引力潮汐场的奇偶性也被量子化时，它们才能纠缠。 我们还指出一个可能的漏洞，由于牛顿常数的微扰展开中高阶项的截断，可能会似乎违反GIE协议。 显示英文摘要

In this note, we consider specific scenarios of matter-gravity interaction based on the source theory to clarify the issue regarding the Gravitationally Induced Entanglement (GIE) protocol, which posits that the detection of quantum entanglement induced by a pure gravitational effect serves as a probe of quantum gravity. Thus, the GIE protocol implies that classical gravity cannot produce or mediate quantum entanglement, to which a recent paper \cite{Aziz:2025ypo} shows the opposite. In all three scenarios of matter-gravity interactions, including mini-superspace, semiclassical gravity, and stochastic gravity approaches, our results agree with the GIE protocol and its implications. More precisely, we show that the mesoscopic quantum bodies with their parities of mass quadrupoles interacting via Newtonian gravity can get entangled only if the parity of the gravitational tidal field sourced by the quantum body is also quantized. We also point out a possible loophole that could seemingly violate the GIE protocol due to the truncation of higher-order terms in the perturbative expansion by orders of the Newton constant.

[36] arXiv:2507.21885 (替换) [中文pdf, pdf, html, 其他]

标题： 从准局部定义到动态势：动态时空中演化圆轨道的统一框架 显示英文标题

标题： From quasi-local definitions to a dynamical potential: A unified framework for evolving circular orbits in dynamical spacetimes

Reggie C. Pantig, Ali Övgün, Syed Masood, Li-Gang Wang

评论： 13页，1图，已接受版本在EPJC

期刊参考： 欧洲物理杂志C 85, 1318 (2025)

主题： 广义相对论与量子宇宙学 (gr-qc)

在引力物理中，研究圆轨道是基础性的，但由于缺乏时间对称性，它们在动态时空中的定义仍然具有挑战性。 在本工作中，我们通过从粒子表面的几何不变局部定义出发，建立了一个统一的框架。 我们证明，这个定义自然导致一组条件，这些条件可以重新表述为坐标相关的动态势的语言。 这个势作为定位特定坐标系中演化的圆轨道的实用计算工具。 我们在动态球对称时空中严格证明了局部和动态势方法之间的等价性。 通过将其应用于Oppenheimer-Snyder尘埃坍缩模型，动态势方法的有效性和自洽性得到了明确验证，在此模型中，它正确地再现了光和类时圆轨道的已知演化方程。 这项工作弥合了抽象几何定义与具体计算之间的差距，提供了一个强大且适应性强的框架，用于分析时变引力场中的轨道动力学。 显示英文摘要

The study of circular orbits is fundamental in gravitational physics, yet their definition in dynamical spacetimes remains challenging due to the lack of temporal symmetry. In this work, we establish a unified framework by commencing from the geometrically invariant quasi-local definition of a particle surface. We demonstrate that this definition naturally leads to a set of conditions that can be recast into the language of a coordinate-dependent dynamical potential. This potential serves as a practical computational tool for locating evolving circular orbits within a specific coordinate system. We rigorously prove the equivalence between the quasi-local and dynamical potential approaches in dynamical spherically symmetric spacetimes. The efficacy and self-consistency of the dynamical potential method are explicitly verified through its application to the Oppenheimer-Snyder dust collapse model, where it correctly reproduces the established evolution equations for null and timelike circular orbits. This work bridges the gap between abstract geometric definitions and concrete calculations, providing a robust and adaptable framework for analyzing orbital dynamics in time-dependent gravitational fields.

[37] arXiv:2511.14080 (替换) [中文pdf, pdf, html, 其他]

标题： 周期轨道及其在$γ$度规中的引力波辐射 显示英文标题

标题： Periodic orbits and their gravitational wave radiations in $γ$-metric

Mohit Thakre, Praveen Kumar Dhankar, Behnam Pourhassan, Safiqul Islam

评论： 16页，11图

主题： 广义相对论与量子宇宙学 (gr-qc) ; 高能物理 - 理论 (hep-th)

伽马度规，也称为Zipoy-Voorhees时空，是一个静态的、轴对称的真空解，由两个参数：质量和变形参数伽马来表征。当伽马等于1时，它退化为施瓦茨希尔德度规。在本文中，我们探讨伽马度规在周期轨道及其引力波辐射上的潜在特征。周期轨道由一个旋转数分类，该旋转数由三个拓扑数（z，w，v）指定，每个三元组对应于特征性的zoom-whirl行为。我们表明，伽马等于1的偏离会改变束缚轨道的半径和角动量，从而改变（z，w，v）分类法。我们还计算了某些周期轨道的代表性引力波形，并证明伽马不等于1可以引起与zoom-whirl结构变化相关的相位偏移和振幅调制。特别是，更大的zoom数会导致波形中出现越来越复杂的子结构，而伽马等于1的有限偏离可以显著修改这些特征。我们的结果表明，从极端质量比吸积中精确测量波形形态可能约束伽马中编码的球对称性偏差。 显示英文摘要

The gamma-metric, also known as Zipoy-Voorhees spacetime, is a static, axially symmetric vacuum solution to Einstein's field equations characterized by two parameters: mass and the deformation parameter gamma. It reduces to the Schwarzschild metric when gamma = 1. In this paper we explore potential signatures of the gamma-metric on periodic orbits and their gravitational-wave radiation. Periodic orbits are classified by a rotational number specified by three topological numbers (z, w, v), each triple corresponding to characteristic zoom-whirl behavior. We show that deviations from gamma=1 alter the radii and angular momentum of bound orbits and thereby shift the (z, w, v) taxonomy. We also compute representative gravitational waveforms for certain periodic orbits and demonstrate that gamma != 1 can induce phase shifts and amplitude modulations correlated with changes in the zoom-whirl structure. In particular, larger zoom numbers lead to increasingly complex substructures in the waveforms, and finite deviations from gamma=1 can significantly modify these features. Our results indicate that precise measurements of waveform morphology from extreme-mass-ratio inspirals may constrain deviations from spherical symmetry encoded in gamma.

[38] arXiv:2511.08527 (替换) [中文pdf, pdf, html, 其他]

标题： 球形薄壳虫洞在标量-张量理论中的稳定性 显示英文标题

标题： Stability of spherical thin-shell wormholes in scalar-tensor theories

A. A. M. Silva, G. Alencar, C. R. Muniz, M. Nilton, R. R. Landim

评论： 13页，1图。V2：更正后的版本，有重要修改，新增了参考文献

主题： 广义相对论与量子宇宙学 (gr-qc)

在本文中，我们在标量-张量引力理论中构建了一类球对称的薄壳虫洞。 在虫洞关于喉部对称的情况下，我们研究了物质内容并分析了静态配置在径向扰动下的稳定性。 我们将该形式应用于一个涉及爱因斯坦-麦克斯韦引力与共形不变标量场耦合的特定例子。 我们表明，对于相关参数的适当值，可能存在稳定的配置。 显示英文摘要

In this article, we construct a family of spherically symmetric thin-shell wormholes within scalar-tensor theories of gravity. In the case of wormholes symmetric across the throat, we study the matter content and analyze the stability of the static configurations under radial perturbations. We apply the formalism to a particular example involving Einstein-Maxwell gravity coupled to a conformally invariant scalar field. We show that stable configurations are possible for suitable values of the parameters involved.

[39] arXiv:2511.06579 (替换) [中文pdf, pdf, html, 其他]

标题： 黑洞的拓扑热力学：重新审视环绕数计算方法 显示英文标题

标题： Topological Thermodynamics of Black Holes: Revisiting the methods of winding numbers calculation

Yong Xiao, Aonan Zhang

评论： 11页，3图

主题： 广义相对论与量子宇宙学 (gr-qc) ; 数学物理 (math-ph)

在本文中，建立了两种计算绕数方法之间的等价性：$φ$-映射拓扑电流的方法和留数方法。 当条件$M'' S' - S'' M' \neq 0$成立时，这些方法被证明是等价的，而当此关系失效时会出现偏差，这表明质量$M(r_h)$、熵$S(r_h)$和拓扑结构之间存在微妙的联系，其中$r_h$是视界半径。 我们首先验证了这种等价性对于施瓦茨希尔德黑洞和雷斯纳-诺斯特朗姆黑洞的情况，恢复了已知的分类，并确认了我们方法相对于上述条件有效性的一致性。 随后，我们将分析扩展到四维的黑弦，这些黑弦被视为渐近AdS时空中的圆柱对称黑洞解。 我们的结果表明，中性和带电的黑弦都具有相同的全局拓扑数$W = +1$，这意味着电荷不会影响它们的拓扑分类。 这种对电荷的不敏感性与三维空间中BTZ黑洞的早期发现相一致，表明这可能是AdS背景中圆柱对称黑洞的一个普遍特性。 显示英文摘要

In this paper, the equivalence between two methods for computing winding numbers is established: the approach of $φ$-mapping topological current and the residue method. The methods are shown to be equivalent when the condition $M'' S' - S'' M' \neq 0$ holds, while deviations appear when this relation fails, signaling subtle connections between mass $M(r_h)$, entropy $S(r_h)$, and topological structure, with $r_h$ being the horizon radius. We first verify this equivalence to Schwarzschild and Reissner-Nordstr"om black holes, recovering known classifications and confirming the consistency of our approach with respect to the validity of the above condition. We then extend the analysis to four-dimensional black strings, regarded as cylindrically symmetric black hole solutions in asymptotically AdS spacetimes. Our results show that both neutral and charged black strings possess the same global topological number, $W = +1$, implying that electric charge does not influence their topological classification. This insensitivity to charge mirrors earlier findings for BTZ black holes in three dimensions, suggesting that it may represent a universal property of cylindrically symmetric black holes in AdS backgrounds.

[40] arXiv:2411.01441 (替换) [中文pdf, pdf, html, 其他]

标题： 更多的非线性？ II. 史瓦西背景中一阶和二阶电磁扰动的简要指南 显示英文标题

标题： More Nonlinearities? II. A Short Guide of First- and Second-Order Electromagnetic Perturbations in the Schwarzschild Background

Ernesto F. Eiroa, Griselda Figueroa-Aguirre, Vasiliki Karanasou

评论： 20页，25图

主题： 广义相对论与量子宇宙学 (gr-qc) ; 高能物理 - 现象学 (hep-ph) ; 高能物理 - 理论 (hep-th) ; 数学物理 (math-ph)

我们研究了施瓦茨希尔德背景下的二阶电磁扰动，并推导了Regge-Wheeler方程的有效源项，这些源项是一阶引力和电磁扰动的二次项。 除了诱导的混合二次模式外，我们还发现线性引力模式也被激发，其振幅依赖于电磁势。 一个涉及狄拉克δ函数势的模型展示了线性引力和电磁扰动在频率\( ω^{(1)} \)和\( Ω^{(1)} \)下的混合，导致电磁场中二阶QNM混合出现在\( Ω^{(2)} =Ω^{(1)} + ω^{(1)} \)。 这补充了\cite{aly2024nonlinearities}中关于二阶引力扰动混合的先前工作，并突显了在LIGO-Virgo-KAGRA（LVK）和即将推出的LISA观测系统中的多信使天体物理学的潜在应用。 我们还研究了点电荷引起的一阶扰动，并表明它可以简化为一维路径积分。 在该模型中，我们研究了径向自由下落的单电荷\( q \)和径向偶极矩\( p = q η\)引起的一阶电磁扰动，采用了半解析和数值方法。 对于偶极子情况，我们表明QNM扰动被激发，其振幅几乎恒定。 未来的工作将集中在更现实势场中的混合效应，并探索旋转时空背景下的数值方法。 显示英文摘要

We study second-order electromagnetic perturbations in the Schwarzschild background and derive the effective source terms for Regge-Wheeler equation which are quadratic in first-order gravitational and electromagnetic perturbations. In addition to the induced mixed quadratic modes, we find that linear gravitational modes are also excited, with amplitudes dependent on the electromagnetic potential. A toy model involving a Dirac delta function potential demonstrates mixing of linear gravitational and electromagnetic perturbations with frequencies \( ω^{(1)} \) and \( Ω^{(1)} \), resulting in the second-order QNM mixing in the electromagnetic field at \( Ω^{(2)} =Ω^{(1)} + ω^{(1)} \). This complements prior work in \cite{aly2024nonlinearities} on the second-order gravitational perturbation mixing and highlights potential applications in multi-messenger astrophysics for systems observed by LIGO-Virgo-KAGRA (LVK) and upcoming LISA. We also study first-order perturbations due to a point charge and show it could be reduced to a one-dimensional path integral. Within the toy model, we investigate the first-order electromagnetic perturbation due to a radially free-falling single charge \( q \) and radial dipole moment \( p = q η\), employing semi-analytical and numerical methods. For the dipole case, we show that the QNM perturbation is excited with a nearly constant amplitude. Future work will focus on incorporating mixing in more realistic potentials and exploring numerical approach in the context of rotating spacetimes.

[41] arXiv:2508.06290 (替换) [中文pdf, pdf, html, 其他]

标题： 可穿越的虫洞解在大质量$F(T)$引力中 显示英文标题

标题： Traversable Wormhole Solutions in massive $F(T)$ gravity

Jorge Lamas

评论： 22页，3图，提交至《经典与量子引力》

主题： 广义相对论与量子宇宙学 (gr-qc) ; 高能物理 - 理论 (hep-th) ; 数学物理 (math-ph)

我们研究在$F(T)$引力框架中补充一个弱德·拉姆-加巴达德泽-托利（dRGT）大质量项的情况下可穿越虫洞几何结构。 使用静态和球对称的莫里斯-索恩度规，我们推导出场方程和守恒方程，将有效能量动量张量分离为扭力和大质量贡献。 我们分析了三种典型的度规红移函数类别，即常数、对数和幂律形式，以及大质量项的两种情况，即一般情况和均匀压强情况。 所得解满足外扩条件并保持渐近平坦，而有效物质部分可以满足或仅轻微违反标准能量条件。 结果表明，小引力子质量的引入提供了一个额外的各向异性压强，可以在不引入奇异源的情况下维持喉部几何结构。 在引力子质量消失的极限情况下，这些配置连续地减少到标准$F(T)$虫洞解，确认了该框架的一致性。 显示英文摘要

We investigate traversable wormhole geometries in the framework of $F(T)$ gravity supplemented by a weak de Rham-Gabadadze-Tolley (dRGT) massive term. Using the static and spherically symmetric Morris-Thorne metric, we derive the field and conservation equations, separating the effective energy-momentum tensor into torsional and massive contributions. We analyze three representative classes of metric redshift functions, namely constant, logarithmic, and power-law forms, and two cases of the massive term, i.e. the general one and the uniform pressure case. The obtained solutions satisfy the flaring-out condition and remain asymptotically flat, while the effective matter sector can fulfill or only mildly violate the standard energy conditions. The results show that the inclusion of a small graviton mass provides an additional anisotropic pressure that can sustain the throat geometry without introducing exotic sources. In the limit of vanishing graviton mass, the configurations continuously reduce to the standard $F(T)$ wormhole solutions, confirming the consistency of the framework.

[42] arXiv:2204.08484 (替换) [中文pdf, pdf, html, 其他]

标题： 揭示暗第五力的线性宇宙学 显示英文标题

标题： Unveiling dark fifth forces with linear cosmology

Fawzi Aly, Dejan Stojkovic

评论： 54页，15图。v2：修订了第6节，现在包括原子钟约束；增加了表1，包含主要结果；扩展了BAO的讨论；增加了参考文献。与JCAP版本一致。v3：修复了一些错误的方程，所有结果和图表不受影响。更新了最新的MICROSCOPE和钟的约束。v4：修复了解析亚视界解（第4.2.1节）中的一些系数。

期刊参考： JCAP 10 (2022) 074

主题： 宇宙学与非星系天体物理学 (astro-ph.CO) ; 高能物理 - 现象学 (hep-ph)

我们开始探索暗第五力的宇宙学：仅作用于暗物质的新力。 我们关注长程相互作用，这些相互作用会导致今天在宇宙学尺度上有效违反等效原理。 在微观层面，暗第五力可以通过一个质量小于当今哈勃常数的轻标量（$\lesssim 10^{-33}\,\text{eV}$）实现，并与暗物质耦合。 我们研究了这种宇宙中的背景宇宙学和线性扰动行为。 在背景层面上，新力会改变暗物质能量密度的演化，从而影响哈勃流。 在一阶近似下，它会改变物质扰动的增长，并在暗物质和重子之间产生随时间增长的相对密度和速度扰动。 我们从当前的CMB和BAO数据中推导出约束，将暗第五力的强度限制为小于引力的一个百分点。 这是目前最强的约束。 我们提出了这种情景对哈勃张力的潜在影响，并讨论了如果轻标量媒介解释了观测到的暗能量密度，我们的结果会如何变化。 最后，我们评论了我们的约束与可见领域中等效原理破坏搜索之间的相互作用。 显示英文摘要

We initiate the exploration of the cosmology of dark fifth forces: new forces acting solely on Dark Matter. We focus on long range interactions which lead to an effective violation of the Equivalence Principle on cosmological scales today. At the microscopic level, the dark fifth force can be realized by a light scalar with mass smaller than the Hubble constant today ($\lesssim 10^{-33}\,\text{eV}$) coupled to Dark Matter. We study the behavior of the background cosmology and linear perturbations in such a Universe. At the background level, the new force modifies the evolution of the Dark Matter energy density and thus the Hubble flow. At linear order, it modifies the growth of matter perturbations and generates relative density and velocity perturbations between Dark Matter and baryons that grow over time. We derive constraints from current CMB and BAO data, bounding the strength of the dark fifth force to be less than a percent of gravity. These are the strongest constraints to date. We present potential implications of this scenario for the Hubble tension and discuss how our results are modified if the light scalar mediator accounts for the observed density of the Dark Energy. Finally, we comment on the interplay between our constraints and searches for violations of the Equivalence Principle in the visible sector.

[43] arXiv:2511.13812 (替换) [中文pdf, pdf, html, 其他]

标题： 轻于QCD轴子对中子星潮汐变形性的影响 显示英文标题

标题： Effects of Lighter-than-QCD Axions on Neutron Star Tidal Deformability

Debottam Nandi (CCSP, SGT University), Simran Yadav (University of Delhi), Manjeet Kaur (University of Delhi)

评论： 18页，10图，5页的附录

主题： 高能物理 - 现象学 (hep-ph) ; 高能天体物理现象 (astro-ph.HE) ; 广义相对论与量子宇宙学 (gr-qc)

轻于QCD轴子的有限密度修正可以反转有效轴子势，从而在致密天体内部产生非平凡的轴子场。 我们进行了首次在1+1维广义相对论中对轻于QCD轴子在中子星中的完整动力学的数值研究，并将分析区域扩展到具有千米尺度康普顿波长的低质量轴子。 我们计算了轴子场对中子星的引力效应，并表明对于广泛的轴子质量和衰变常数，中子星的性质，如质量、半径和致密性，都会在一级量级上受到影响。 这一结果表明，中子星的近似普遍潮汐变形-致密性关系被非平凡地破坏，并可以作为探测轻于QCD轴子的工具，而无需依赖未知的核方程状态。 我们评论了未来中子星引力波观测在轴子研究中的潜力，以及本工作在其他新物理信号应用方面的可能性。 显示英文摘要

Finite density corrections to the lighter-than-QCD axion can invert the effective axion potential, sourcing a non-trivial axion field inside dense objects. We perform the first numerical study of the complete dynamics of the lighter-than-QCD axion in a neutron star in 1+1 general relativity, extending the region of analysis to low-mass axions with kilometer-scale Compton wavelengths. We calculate gravitational effects of the axion field on the neutron star and show that for a broad range of axion masses and decay constants, neutron star properties, such as the mass, radius, and compactness, are affected at the order-1 level. This result indicates that approximate universal tidal deformability-compactness relation for neutron stars is non-trivially broken and can serve as a probe of lighter-than-QCD axions, independent of the unknown nuclear equation of state. We comment on the potential for axion studies with future gravitational-wave observations of neutron stars and applications of this work to other new physics signatures.

[44] arXiv:2506.16462 (替换) [中文pdf, pdf, html, 其他]

标题： Reticulum II超弱矮星系中的双峰金属丰度分布函数 显示英文标题

标题： A Bimodal Metallicity Distribution Function in the Ultra-Faint Dwarf Galaxy Reticulum II

Albert Escrivà

评论： 16页 + 2个附录，14幅图，4张表。发表于《开放天体物理学杂志》

主题： 星系的天体物理学 (astro-ph.GA) ; 太阳与恒星天体物理学 (astro-ph.SR)

超微弱矮星系（UFDs，$M_* <10^5M_\odot$）中的恒星形成受到再电离的抑制，但可能并未完全停止。 超微弱矮星系中恒星的金属丰度分布函数（MDF）可能会显示出再电离的这些特征。 然而，过去对UFD MDF的研究受到了限制，因为这类低质量星系中只有几十颗红巨星分支（RGB）恒星。 我们提供了对超微弱矮星系Reticulum II（$M_* \approx 3000 M_\odot$）中167颗恒星的低分辨率Magellan/IMACS光谱观测，使恒星金属丰度的数量增加了6.5倍，并得到了任何UFD中最丰富的光谱金属丰度分布函数。 这成为可能是因为我们确定了任何UFD中主序星转折点恒星的第一个光谱金属丰度。 Reticulum II的MDF明显是一个双峰分布，显示两个峰值，约有$80\%$的恒星位于金属贫乏的峰值处，金属丰度为$\rm[Fe/H]=-3.0$，而约有$20\%$的恒星位于更富金属的峰值处，金属丰度为$\rm[Fe/H]=-2.1$。 如此大的金属丰度差距可以通过在长时间静止期期间Ia型超新星的增丰来解释。 这支持了目前普遍接受的Reticulum II的两次爆发恒星形成历史，并表明这种低质量星系显然可以在再电离之后形成恒星。 显示英文摘要

Star formation in ultra-faint dwarf galaxies (UFDs, $M_* <10^5M_\odot$) is suppressed by reionization, but may not be completely quenched. The metallicity distribution function (MDF) of stars in ultra-faint dwarf galaxies could show these signatures of reionization. However, past studies of UFD MDFs have been limited, because there are only a few dozen red giant branch (RGB) stars in such low-mass galaxies. We present low-resolution Magellan/IMACS spectroscopy of 167 stars in the UFD Reticulum II ($M_* \approx 3000 M_\odot$), increasing the number of stellar metallicities by 6.5 times and resulting in the most populated spectroscopic metallicity distribution function of any UFD. This is possible because we determined the first spectroscopic metallicities of main sequence turn-off stars in any UFD. The MDF of Reticulum II is clearly a bimodal distribution, displaying two peaks with about $80\%$ of the stars in the metal-poor peak at $\rm[Fe/H]=-3.0$ and $20\%$ of the stars in the more metal-rich peak at $\rm[Fe/H]=-2.1$. Such a large metallicity gap can be explained by Type Ia supernova enrichment during a long quiescent period. This supports the currently-favored two-burst star formation history for Reticulum II and shows that such low-mass galaxies clearly can form stars after reionization.

[45] arXiv:2511.14350 (替换) [中文pdf, pdf, html, 其他]

标题： 黑洞蒸发的量子电路模型与受控因果泄漏 显示英文标题

标题： Quantum Circuit Model of Black Hole Evaporation with Controlled Causal Leakage

Zong-Zhe Du, David Stefanyszyn

评论： 23页，5图

主题： 高能物理 - 理论 (hep-th) ; 广义相对论与量子宇宙学 (gr-qc) ; 量子物理 (quant-ph)

我们扩展了一个四量子比特黑洞蒸发的量子电路模型，该模型强制执行半因果性，这是一种允许信息进入黑洞但严格禁止任何信息从内部通过视界逃逸到外部的条件。 在本工作中，我们通过插入一个参数化的可控单元门引入了对该原理的受控破坏，该门能够使量子信息从黑洞内部可调地泄漏到外部，同时保持全局单元性。 通过改变变形参数，我们研究了在蒸发过程中纠缠熵、互信息和纠缠否定性的演化。 虽然半因果情况下产生了一个类似Page的熵曲线，且晚期时间相关性消失，但我们发现即使是对半因果性的微小破坏也会在视界处产生非零的剩余熵和持续的否定性。 这些特性模仿了量子引力引起的效应，如残留物形成和视界渗透性，表明对经典因果性的最小偏离可以在黑洞信息动力学中留下持久的痕迹。 显示英文摘要

We extend a four-qubit quantum circuit model of black hole evaporation that enforces semi-causality, a condition that allows information to enter a black hole but strictly forbids any information from escaping from the interior to outside through the horizon. In this work, we introduce a controlled violation of this principle by inserting a parametric controlled-unitary gate that enables a tunable leakage of quantum information from the black hole interior to the exterior, while preserving global unitarity. By varying the deformation parameter, we study the evolution of entanglement entropy, mutual information, and entanglement negativity throughout the evaporation process. While the semi-causal case yields a Page-like entropy curve with vanishing late-time correlations, we find that even small violations of semi-causality produce a non-zero residual entropy and persistent negativity across the horizon. These features mimic quantum-gravity-induced effects such as remnant formation and horizon permeability, suggesting that minimal deviations from classical causality can leave long-lived imprints on black hole information dynamics.

[46] arXiv:2511.07209 (替换) [中文pdf, pdf, html, 其他]

标题： 背景减法方法在物质耦合引力理论中的黑洞热力学有效性 显示英文标题

标题： On the Validity of the Background Subtraction Method for Black Hole Thermodynamics in Matter-Coupled Gravity Theories

Wangyu Ai, Di Wu

评论： 9页，无图表，一些拼写错误已更正

主题： 广义相对论与量子宇宙学 (gr-qc) ; 高能物理 - 理论 (hep-th)

背景减法方法长期以来一直作为计算黑洞的欧几里得作用量和热力学量的实用工具。 尽管在纯引力理论中其与Iyer--Wald形式主义的等价性已被充分理解，但在物质耦合理论中的有效性仍不够明确，甚至在文献中受到质疑。 在本工作中，我们重新审视这一问题，并证明在物质耦合情况下，欧几里得作用量方法与Iyer--Wald形式主义之间的等价性仍然成立。 我们将所得出的公式应用于这类理论的两个代表性例子，在这两种情况下，欧几里得方法都能顺利运行。 我们进一步识别了由于某些物质场的特殊性质可能导致该方法出现细微问题的情况。 我们的结果明确了在纯引力之外背景减法何时仍然可靠，以及何时需要额外注意。 显示英文摘要

The background subtraction method has long served as a practical tool for computing the Euclidean action and thermodynamic quantities of black holes. While its equivalence to the Iyer--Wald formalism is well understood in pure gravity theories, its validity in matter-coupled theories remains less clear and has even been questioned in the literature. In this work, we revisit this issue and demonstrate that the equivalence between the Euclidean action method and the Iyer--Wald formalism persists in matter-coupled scenarios. We apply the resulting formulation to two representative examples of such theories, and in both cases, the Euclidean approach performs smoothly. We further identify situations where the method may encounter subtleties due to the special properties of certain matter fields. Our results clarify when background subtraction remains reliable beyond pure gravity and when additional care is necessary.

[47] arXiv:2510.06458 (替换) [中文pdf, pdf, html, 其他]

标题： 新的渐近平坦的爱因斯坦-麦克斯韦瞬子 显示英文标题

标题： New asymptotically flat Einstein--Maxwell instantons

Weizhen Jia, Qiongyu Qi, Christina Gao

评论： 最终版本。NUT参数从杆结构中显式计算得出。将发表在《物理评论快报》上

主题： 广义相对论与量子宇宙学 (gr-qc) ; 高能物理 - 理论 (hep-th) ; 微分几何 (math.DG)

我们否定了欧几里得爱因斯坦-麦克斯韦黑洞唯一性猜想，从而表明耦合引力和电磁场的半经典性质比从洛伦兹广义相对论中预期的更为微妙，在洛伦兹广义相对论中，Kerr-Newman度规族给出了具有单个事件视界的最一般的静态且渐近平坦的黑洞。 这是通过显式构造一个新的三参数渐近平坦的爱因斯坦-麦克斯韦瞬子族来实现的。 这些解是环状的、规则的，并且在流形$M=\CP^2\setminus S^1$上没有锥形和轨道奇异点。 在电荷为零的情况下，这些瞬子退化为Chen--Teo Ricci平坦瞬子。 显示英文摘要

We disprove the Euclidean Einstein--Maxwell Black Hole Uniqueness Conjecture, and thus demonstrate that the semi-classical properties of coupled gravitational and electromagnetic fields are more subtle than expected from Lorentzian general relativity, where the Kerr-Newman family of metrics yields the most general stationary and asymptotically flat black holes with a single event horizon. This is achieved by an explicit construction of a new three--parameter family of asymptotically flat Einstein--Maxwell instantons. These solutions are toric, regular, and free of conical and orbifold singularities on the manifold $M=\CP^2\setminus S^1$. In the case of vanishing charge, these instantons reduce to the Chen--Teo Ricci flat instantons.

[48] arXiv:2511.14044 (替换) [中文pdf, pdf, html, 其他]

标题： CHASM-SWPC 日冕洞检测与分析数据集 显示英文标题

标题： The CHASM-SWPC Dataset for Coronal Hole Detection & Analysis

Dimitrios Efstratiou, Evangelos Achilleas Paraskevas, Leandros Perivolaropoulos

主题： 天体物理学的仪器与方法 (astro-ph.IM) ; 计算机视觉与模式识别 (cs.CV) ; 机器学习 (cs.LG)

日冕洞（CHs）是低活动性、低密度的太阳日冕区域，具有开放的磁场线（Cranmer 2009）。 在极端紫外（EUV）光谱中，CHs表现为暗斑。 使用来自空间天气预测中心（SWPC）的每日手工绘制地图，我们开发了一个半自动流程，将SWPC地图数字化为二进制分割掩膜。 这些掩膜构成了CHASM-SWPC数据集，这是一个高质量的数据集，用于训练和测试自动CH检测模型，该数据集随本文一起发布。 我们开发了CHASM（使用半自动方法的日冕洞标注），一种用于半自动标注的软件工具，使用户能够快速准确地标注SWPC地图。 CHASM工具使我们标注了1,111个CH掩膜，构成了CHASM-SWPC-1111数据集。 然后，我们使用CHASM-SWPC数据集训练了多个CHRONNOS（多光谱数据的日冕洞识别神经网络）架构（Jarolim等，2021）神经网络，并比较了它们的性能。 在这些数据上训练CHRONNOS神经网络达到了0.9805的准确率，0.6807的真技能统计量（TSS）和0.5668的交并比（IoU），这高于原始预训练的CHRONNOS模型Jarolim等（2021）在CHASM-SWPC-1111测试集上达到的0.9708的准确率，0.6749的TSS和0.4805的IoU。 显示英文摘要

Coronal holes (CHs) are low-activity, low-density solar coronal regions with open magnetic field lines (Cranmer 2009). In the extreme ultraviolet (EUV) spectrum, CHs appear as dark patches. Using daily hand-drawn maps from the Space Weather Prediction Center (SWPC), we developed a semi-automated pipeline to digitize the SWPC maps into binary segmentation masks. The resulting masks constitute the CHASM-SWPC dataset, a high-quality dataset to train and test automated CH detection models, which is released with this paper. We developed CHASM (Coronal Hole Annotation using Semi-automatic Methods), a software tool for semi-automatic annotation that enables users to rapidly and accurately annotate SWPC maps. The CHASM tool enabled us to annotate 1,111 CH masks, comprising the CHASM-SWPC-1111 dataset. We then trained multiple CHRONNOS (Coronal Hole RecOgnition Neural Network Over multi-Spectral-data) architecture (Jarolim et al. 2021) neural networks using the CHASM-SWPC dataset and compared their performance. Training the CHRONNOS neural network on these data achieved an accuracy of 0.9805, a True Skill Statistic (TSS) of 0.6807, and an intersection-over-union (IoU) of 0.5668, which is higher than the original pretrained CHRONNOS model Jarolim et al. (2021) achieved an accuracy of 0.9708, a TSS of 0.6749, and an IoU of 0.4805, when evaluated on the CHASM-SWPC-1111 test set.

[49] arXiv:2506.17192 (替换) [中文pdf, pdf, html, 其他]

标题： 广义相对论中静态和轴对称解中的引力透镜观测量 显示英文标题

标题： Gravitational lensing observables in stationary and axisymmetric solutions in general relativity

Satish Ramakrishna

评论： 16页，LaTeX；已修改以符合PRD期刊接受的版本

期刊参考： 物理评论D 112，104044（2025）

主题： 广义相对论与量子宇宙学 (gr-qc)

我们研究由轴对称、稳态、旋转的尘埃流体组成的自引力系统中的光传播。 这些配置本质上是相对论性的，完全由其旋转维持，因为在牛顿引力中，在相同的对称条件 下，不存在紧凑或有限的尘埃分布。 在这样的系统中，旋转效应来自于时空度规的非对角分量，这些分量与它们的牛顿对应项相比并不可以忽略。 我们分析这些分量如何影响光的偏转角度，表明它们可以被解释为贡献了一个额外的有效质量。 此外，从原则上讲，它们的存在可以通过它们在背景源图像中引起的特征不对称性来检测。 显示英文摘要

We investigate light propagation in self-gravitating systems composed of an axially symmetric, stationary, rotating dust fluid. These configurations are intrinsically relativistic, sustained entirely by their rotation, since no compact or finite dust distribution can exist under the same symmetry conditions in Newtonian gravity. In such systems, rotational effects arise from off-diagonal components of the spacetime metric, which are not negligible compared to their Newtonian counterparts. We analyze how these components affect the deflection angle of light, showing that they can be interpreted as contributing an additional effective mass. Moreover, their presence can, in principle, be detected through the characteristic asymmetry they induce in the images of background sources.