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Holographic complexity and the Hubble tension: a quantum gravity portrayal for the large scale structure of the cosmos 全息复杂性和哈勃张力:宇宙大尺度结构的量子引力写照
IF 3.5 3区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2025-12-10 DOI: 10.1088/1361-6382/ae2416
Carlos Silva
In this paper, we propose a relationship between the so-called Hubble–Lemaî tre constant H0 and the holographic complexity related to the emergence of spacetime in quantum gravity. Such a result can represent an important step to understanding the Hubble tension by introducing a quantum gravity perspective for cosmological observations, regarding the degree of quantum complexity we measure around us.
在本文中,我们提出了所谓的Hubble-Lemaî三常数H0与量子引力中时空出现相关的全息复杂性之间的关系。这样的结果代表了理解哈勃张力的重要一步,通过引入宇宙学观测的量子引力视角,考虑到我们周围测量的量子复杂性的程度。
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引用次数: 0
Effect of noncommutative geometry on accretion disks around RGI-Schwarzschild black hole 非交换几何对rgi -史瓦西黑洞吸积盘的影响
IF 3.5 3区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2025-12-10 DOI: 10.1088/1361-6382/ae255d
Dilip Kumar
In this study, we explore the combined effects of quantum gravity induced by non-commutativity and scale-dependent gravitational coupling on the thermal properties of the thin accretion disks around a Schwarzschild black hole. We consider a κ-deformed renormalization group induced (RGI) Schwarzschild black hole, where the classical Schwarzschild black hole geometry is modified by the κ-deformation of space-time and the running Newton’s coupling constant G(r). Using the modified metric, we derive the geodesic motion of massive particles, the effective potential, and the thermal properties such as the radiated energy flux, luminosity, and the temperature profile of the accretion disk around the κ-deformed RGI-Schwarzschild black hole. Our study shows that when non-commutativity is combined with the RGI framework, the effects produce a noticeable deviation from the classical Schwarzschild case. In particular, for small values of the deformation parameter, we observe an increase in the peak energy flux and the temperature of the accretion disk. This suggests that quantum gravity corrections enhance the disk’s radiative efficiency, especially in the inner regions closer to the black hole.
在这项研究中,我们探讨了由非交换性和尺度相关引力耦合引起的量子引力对史瓦西黑洞周围薄吸积盘热性质的综合影响。我们考虑了一个κ变形重整化群诱导(RGI)史瓦西黑洞,其中经典史瓦西黑洞几何由时空的κ变形和运行中的牛顿耦合常数G(r)修正。利用改进的度量,我们推导出了大质量粒子的测地线运动、有效势、辐射能量通量、光度和吸积盘的温度分布等热性质。我们的研究表明,当非交换性与RGI框架相结合时,其效应与经典的史瓦西情况产生了明显的偏差。特别地,当变形参数值较小时,我们观察到吸积盘的峰值能量通量和温度都有所增加。这表明量子引力修正提高了圆盘的辐射效率,特别是在靠近黑洞的内部区域。
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引用次数: 0
Angular velocity of rotating black holes—a new way to construct initial data for binary black holes 旋转黑洞角速度——构建双黑洞初始数据的一种新方法
IF 3.5 3区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2025-12-08 DOI: 10.1088/1361-6382/ae2414
Shuanglin Huang, Xuefeng Feng and Yun-Kau Lau
Motivated by a geometric understanding of the angular velocity of a Kerr black hole in terms of a quasi-conformal map that describes a 2d Beltrami fluid flow, a new way to construct initial data sets for binary rotating black holes by prescribing the angular velocities of the two black holes at their horizons is discussed. A set of elliptic equations with prescribed Dirichlet boundary conditions at the horizons and at spatial infinity is established for constructing the initial data. To explore the dynamics encoded in these initial data, we consider the conformally flat three-metric case and numerically evolve it using the BSSN code for two co-rotating and counter-rotating black holes with angular velocities prescribed at the horizons. When the angular velocities are non-uniform and deviate from a constant value at the horizons, new gravitational waveforms are generated which display certain oscillatory pattern reminiscent of that of quasi-normal ringing in the inspiral phase before merger takes place.
从描述二维Beltrami流体流动的准保角映射对Kerr黑洞角速度的几何理解出发,讨论了一种通过规定两个黑洞在视界处的角速度来构造二元旋转黑洞初始数据集的新方法。在视界和空间无穷远处建立了一组具有指定Dirichlet边界条件的椭圆方程来构造初始数据。为了探索这些初始数据中编码的动力学,我们考虑了共形平面三度量情况,并使用BSSN代码对视界处规定角速度的两个共旋转和反旋转黑洞进行了数值演化。当角速度不均匀且在视界处偏离恒定值时,产生新的引力波,这些引力波表现出一定的振荡模式,使人联想到合并前吸气阶段的准正振。
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引用次数: 0
Interior-flat cylindrical nacelle warp bubbles: derivation and comparison with Alcubierre model 内平圆柱机舱翘曲气泡:与Alcubierre模型的推导与比较
IF 3.5 3区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2025-12-08 DOI: 10.1088/1361-6382/ae237a
Harold White, Jerry Vera, Andre Sylvester and Leonard Dudzinski
We present a new class of warp bubble geometries that are both interior-flat and segmented into Gaussian cylinders (interchangeably called ‘nacelles’1throughout the paper), providing an alternative to the continuous toroidal energy distribution of the Alcubierre model. Using the ADM 3+1 formalism, we derive the extrinsic curvature, York time, momentum densities, and energy density for both the Alcubierre baseline and the Gaussian cylinder generalizations with cylinders equally spaced azimuthally around the warp bubble. The interior-flat condition guarantees that observers within the bubble remain synchronized with external clocks, yielding a habitable region of flat spacetime. Unlike the diffuse azimuthal ring of negative energy in the Alcubierre solution, our construction localizes exotic stress-energy into discrete cylindrical channels aligned with the bubble wall. Energy density maps, boost magnitude contours, and three-dimensional isosurfaces demonstrate how these segmented Gaussian cylinders maintain a synchronized interior while tuning curvature effects to end-caps. The results suggest that warp bubbles can be engineered with structurally discrete geometries resembling science-fiction starship architectures, where exotic matter localization, end-cap shaping, and interior flatness are tunable engineering parameters consistent with general relativity. These findings extend the ongoing search for physically motivated warp constructs and underscore the value of bridging theoretical warp metrics with engineering-oriented design principles.
我们提出了一类新的翘曲气泡几何形状,它既内部平坦,又被分割成高斯圆柱体(在整篇论文中可互换称为“短舱”),为Alcubierre模型的连续环面能量分布提供了一种替代方案。利用ADM 3+1的形式,我们导出了Alcubierre基线和高斯柱面推广的外在曲率、约克时间、动量密度和能量密度,柱面在曲泡周围的方向上等距。内部平坦的条件保证了气泡内的观测者与外部时钟保持同步,从而产生了一个可居住的平坦时空区域。与Alcubierre溶液中弥漫的负能量方位环不同,我们的构造将外来的应力能量定位到与气泡壁对齐的离散圆柱形通道中。能量密度图、升力等高线和三维等值面展示了这些分段的高斯圆柱体如何在将曲率效应调整到端盖的同时保持内部同步。结果表明,曲速气泡可以设计成结构离散的几何形状,类似于科幻小说中的星际飞船结构,其中奇异物质的局部化、端盖形状和内部平面度是与广义相对论一致的可调工程参数。这些发现扩展了正在进行的对物理驱动的翘曲结构的研究,并强调了将理论翘曲度量与面向工程的设计原则联系起来的价值。
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引用次数: 0
Inference with finite time series: II. The window strikes back 有限时间序列的推理:2。窗户反射光
IF 3.5 3区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2025-12-08 DOI: 10.1088/1361-6382/ae1ac7
Colm Talbot, Sylvia Biscoveanu, Aaron Zimmerman, Tomasz Baka, Will M Farr, Jacob Golomb, Charlie Hoy, Andrew Lundgren, Jacopo Tissino, John Veitch, Aditya Vijaykumar and Michael J Williams
Smooth window functions are often applied to strain data when inferring the parameters describing the astrophysical sources of gravitational-wave transients. Within the LIGO-Virgo-KAGRA collaboration, it is conventional to include a term to account for power loss due to this window in the likelihood function. We show that the inclusion of this factor leads to biased inference. The simplest solution to this, omitting the factor, leads to unbiased posteriors and Bayes factor estimates provided the window does not suppress the signal for signal-to-noise ratios (SNRs) , but unreliable estimates of the absolute likelihood. Instead, we propose a multi-stage method that yields consistent estimates for the absolute likelihood in addition to unbiased posterior distributions and Bayes factors for SNRs . Additionally, we demonstrate that the commonly held wisdom that using rectangular windows necessarily leads to biased inference is incorrect.
在推断描述引力波瞬变天体物理源的参数时,通常将光滑窗函数应用于应变数据。在LIGO-Virgo-KAGRA合作中,通常在可能性函数中包含一个术语来解释由于这个窗口导致的功率损失。我们表明,包含这个因素会导致有偏见的推断。最简单的解决方案是省略该因子,如果窗口不抑制信号的信噪比(SNRs),则会导致无偏后验和贝叶斯因子估计,但绝对似然估计不可靠。相反,我们提出了一种多阶段方法,除了无偏后验分布和信噪比的贝叶斯因子外,还能产生一致的绝对似然估计。此外,我们证明了使用矩形窗口必然导致有偏见推理的普遍观点是不正确的。
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引用次数: 0
Extended Metric-Affine f(R) gravity with dynamical connection in vacuum 真空中具有动力学联系的扩展度量-仿射f(R)引力
IF 3.5 3区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2025-12-05 DOI: 10.1088/1361-6382/ae2228
Damianos Iosifidis
We extend the usual vacuum Metric-Affine f(R) gravity by supplementing it with all parity even quadratic invariants in torsion and non-metricity. As we show explicitly this supplementation drastically changes the status of the theory which now propagates an additional scalar degree of freedom on top of the graviton. This scalar degree of freedom has a geometric origin as it relates to spacetime torsion and non-metricity. The resulting theory can be written equivalently as a metric and torsionless scalar–tensor theory whose potential and kinetic term coupling depend on the choice of the function f(R) and the dimensionless parameters of the quadratic invariants respectively.
我们扩展了通常的真空度量-仿射f(R)引力,在其上补充了所有宇称偶二次不变量的扭转和非度量性。正如我们明确表明的那样,这种补充极大地改变了理论的状态,现在在引力子之上传播了一个额外的标量自由度。这个标量自由度有一个几何起源,因为它与时空扭转和非度量性有关。由此产生的理论可以等效地写成度量和无扭转标量张量理论,其势项和动力学项耦合分别取决于函数f(R)和二次不变量的无量纲参数的选择。
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引用次数: 0
Comparison of quasinormal modes of black holes in f ( T ... f (T…)中黑洞准正态模的比较
IF 3.5 3区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2025-12-05 DOI: 10.1088/1361-6382/ae1e55
Zhen-Xiao Zhang, Chen Lan and Yan-Gang Miao
We investigate the quasinormal modes (QNMs) of static and spherically symmetric black holes (BHs) in vacuum within the framework of gravity, and compare them with those in gravity. Based on the symmetric teleparallel equivalent of general relativity, we notice that the gravitational effects arise from non-metricity (the covariant derivative of metrics) in gravity rather than curvature in f(R) or torsion in . Using the finite difference method and the sixth-order Wentzel-Kramers-Brillouin (WKB) method, we compute the QNMs of massless scalar field and electromagnetic field perturbations. Tables of quasinormal frequencies for various parameter configurations are provided based on the sixth-order WKB method. Our findings reveal the differences in the QNMs of BHs in gravity compared to those in f(R) and gravity. This variation demonstrates the impact of different parameter values, offering insights into the characteristics of gravity. These results provide the theoretical groundwork for assessing alternative gravities’ viability through gravitational wave data, and aid probably in picking out the alternative gravity theory that best aligns with the empirical reality.
在重力框架下研究了真空中静态和球对称黑洞的准正态模,并与重力下的准正态模进行了比较。基于广义相对论的对称远平行等效,我们注意到引力效应是由引力中的非度规性(度规的协变导数)而不是f(R)中的曲率或in的扭转引起的。利用有限差分法和六阶Wentzel-Kramers-Brillouin (WKB)方法,分别计算了无质量标量场和电磁场扰动的QNMs。基于六阶WKB方法,给出了各种参数配置下的拟非正常频率表。我们的研究结果揭示了引力下黑洞的qnm与f(R)和引力下的qnm的差异。这种变化表明了不同参数值的影响,为了解重力的特性提供了见解。这些结果为通过引力波数据评估替代引力的可行性提供了理论基础,并可能有助于挑选出最符合经验现实的替代引力理论。
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引用次数: 0
Beyond Coleman’s instantons 超越科尔曼的瞬子
IF 3.5 3区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2025-12-05 DOI: 10.1088/1361-6382/ae2376
Misao Sasaki, Vicharit Yingcharoenrat and Ying-li Zhang
In the absence of gravity, Coleman’s theorem states that the O(4)-symmetric instanton solution, which is regular at the origin and exponentially decays at infinity, gives the lowest action. Perturbatively, this implies that any small deformation from O(4)-symmetry gives a larger action. In this letter we investigate the possibility of extending this theorem to the situation where the O(4)-symmetric instanton is singular, provided that the action is finite. In particular, we show a general form of the potential around the origin, which realizes a singular instanton with finite action. We then discuss a concrete example in which this situation is realized, and analyze non-trivial anisotropic deformations around the solution perturbatively. Intriguingly, in contrast to the case of Coleman’s instantons, we find that there exists a deformed solution that has the same action as the one for the O(4)-symmetric solution up to the second order in perturbation. Our result implies that there exist non-O(4)-symmetric solutions with finite action beyond Coleman’s instantons, and gives rise to the possibility of the existence of a non-O(4)-symmetric instanton with a lower action.
在没有重力的情况下,科尔曼定理指出,O(4)对称的瞬态解在原点是规则的,在无穷远处呈指数衰减,给出了最低的作用。从摄动的角度来看,这意味着O(4)对称的任何小变形都会产生较大的作用。在这篇文章中,我们研究了将这个定理推广到O(4)对称瞬子是奇异的情况下的可能性,假设作用是有限的。特别地,我们给出了围绕原点的势的一般形式,它实现了具有有限作用的奇异瞬间。然后我们讨论了一个实现这种情况的具体例子,并分析了解周围的非平凡各向异性变形。有趣的是,与Coleman瞬子的情况相反,我们发现存在一种变形解,其作用与O(4)对称解的作用相同,直到二阶摄动。我们的结果表明存在有限作用的非o(4)对称解,并给出了具有较低作用的非o(4)对称解存在的可能性。
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引用次数: 0
Asymptotic limit of null hypersurfaces 零超曲面的渐近极限
IF 3.5 3区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2025-12-05 DOI: 10.1088/1361-6382/ae22b5
Luca Ciambelli
We study null hypersurfaces approaching null infinity in asymptotically flat spacetimes within the Bondi–Sachs gauge. The null Raychaudhuri constraint is shown to asymptote to the Bondi mass-loss formula, interpreted as a stress tensor conservation law. This stress tensor, the null Brown–York tensor, yields a Carrollian stress tensor at null infinity from the bulk. Furthermore, we establish that the canonical phase space on finite-distance null hypersurfaces asymptotes to the Ashtekar–Streubel phase space. This connection between finite-distance null physics and null infinity unveils promising insights.
我们研究了在Bondi-Sachs规范下渐近平坦时空中接近零无穷的零超曲面。零Raychaudhuri约束被证明是渐近线的邦迪质量损失公式,解释为应力张量守恒定律。这个应力张量,零布朗-约克张量,在零无穷远处从体中产生一个卡罗罗应力张量。进一步证明了有限距离零超曲面上的正则相空间渐近于Ashtekar-Streubel相空间。有限距离零物理和零无穷之间的这种联系揭示了有希望的见解。
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引用次数: 0
Remarks on the quasinormal modes of Taub-NUT-AdS4 关于Taub-NUT-AdS4的拟正态
IF 3.5 3区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2025-12-05 DOI: 10.1088/1361-6382/ae1e54
Georgios Kalamakis and Anastasios C Petkou
We present results for the numerical evaluation of scalar quasinormal modes in Taub-NUT-AdS4 spacetimes. To achieve this we consider angular modes that correspond to non-unitary highest weight SU(2) representations since global regularity is not consistent with the presence of complex quasinormal modes. We show that for any non-zero value of the NUT charge n there exists a region in the complex plane that contains only stable quasinormal modes. The radius of this region increases with the horizon distance and decreases with n towards a constant value for infinite n. We also find analytic and numerical evidence for the existence of a critical NUT charge ncr beyond which the lowest lying stable quasinormal modes become overdamped. Our results draw an intricate picture for the holographic fluid of Taub-NUT-AdS4.
我们给出了在Taub-NUT-AdS4时空中标量拟正态模态的数值计算结果。为了实现这一点,我们考虑了对应于非酉最高权SU(2)表示的角模态,因为全局正则性与复杂拟正态模态的存在不一致。我们证明了对于任何非零的NUT电荷n,在复平面上存在一个只包含稳定准正态模的区域。该区域的半径随着视界距离的增加而增大,在无限n时随着n的增大而减小。我们还发现了一个临界NUT电荷ncr的存在性的解析和数值证据,超过这个ncr,最低的稳定准正态模就会变得过阻尼。我们的结果为Taub-NUT-AdS4的全息流体描绘了一幅复杂的图景。
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引用次数: 0
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Classical and Quantum Gravity
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