General Relativity and Gravitation最新文献_第7页

Black hole spectroscopy: status report 黑洞光谱学：现状报告

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-04-29 DOI: 10.1007/s10714-025-03408-y

Gregorio Carullo

引用次数: 0

Bridging time across null horizons 跨越零视界的桥接时间

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-04-28 DOI: 10.1007/s10714-025-03410-4

Anıl Zenginoğlu

{"title":"Bridging time across null horizons","authors":"Anıl Zenginoğlu","doi":"10.1007/s10714-025-03410-4","DOIUrl":"10.1007/s10714-025-03410-4","url":null,"abstract":"<div><p>General relativity, as a diffeomorphism-invariant theory, allows the description of physical phenomena in a wide variety of coordinate systems. In the presence of boundaries, such as event horizons and null infinity, time coordinates must be carefully adapted to the global causal structure of spacetime to ensure a computationally efficient description. Horizon-penetrating time is used to describe the dynamics of infalling matter and radiation across the event horizon, while hyperboloidal time is used to study the propagation of radiation toward the idealized observer at null infinity. In this paper, we explore the historical and mathematical connection between horizon-penetrating and hyperboloidal time coordinates, arguing that both classes of coordinates are simply regular choices of time across null horizons. We review the height-function formalism in stationary spacetimes, providing examples that may be useful in computations, such as source-adapted foliations or Fefferman–Graham–Bondi coordinates near null infinity. We discuss bridges connecting the boundaries of spacetime through a time hypersurface across null horizons, including the event horizon, null infinity, and the cosmological horizon.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 4","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10714-025-03410-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143880828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Linear frame dragging along one spatial dimension 沿着一个空间维度拖动的线性框架

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-04-27 DOI: 10.1007/s10714-025-03407-z

Marco Alberto Javarone, Luciano Pietronero

引用次数: 0

Black holes galore in (D>4) 黑洞大量涌入 (D>4)

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-04-24 DOI: 10.1007/s10714-025-03398-x

Roberto Emparan

引用次数: 0

Gravitational collapse in higher-dimensional Rastall gravity with and without cosmological constant 具有或不具有宇宙常数的高维拉斯托引力中的引力坍缩

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-04-20 DOI: 10.1007/s10714-025-03406-0

Golfin Ekatria, Andy Octavian Latief, Fiki Taufik Akbar, Bobby Eka Gunara

{"title":"Gravitational collapse in higher-dimensional Rastall gravity with and without cosmological constant","authors":"Golfin Ekatria, Andy Octavian Latief, Fiki Taufik Akbar, Bobby Eka Gunara","doi":"10.1007/s10714-025-03406-0","DOIUrl":"10.1007/s10714-025-03406-0","url":null,"abstract":"<div><p>We consider a spherically symmetric homogeneous perfect fluid undergoing a gravitational collapse to singularity in the framework of higher-dimensional Rastall gravity in the cases of vanishing and nonvanishing cosmological constants. The possible final states of the collapse in any finite dimension are black hole and naked singularity, but the naked singularity formation becomes less favored when the dimension is increased. We find that there are two physically distinct solutions for the collapse evolution in the case of nonzero cosmological constant: trigonometric and exponential solutions. The effective energy density of the fluid is decreasing (increasing) in the former (latter) when the magnitude of the cosmological constant is increased, which implies that the former undergoes a slower collapse than the latter. Furthermore, we find that a temporary trapped surface is possible to emerge in the case of trigonometric solution in the naked singularity region only. Therefore, distant observers with observational time shorter than the collapse duration may conclude that a black hole is formed, although the collapse will eventually lead to a naked singularity formation.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 4","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Null geodesics in the static black bottle spacetime 静态黑瓶时空中的零测地线

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-04-17 DOI: 10.1007/s10714-025-03404-2

Hexiang Chang

引用次数: 0

Constraining the f-mode oscillations frequency in neutron stars through universal relations in the realm of energy-momentum squared gravity 利用能量-动量平方重力领域的通用关系约束中子星f模振荡频率

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-04-16 DOI: 10.1007/s10714-025-03405-1

Sayantan Ghosh

{"title":"Constraining the f-mode oscillations frequency in neutron stars through universal relations in the realm of energy-momentum squared gravity","authors":"Sayantan Ghosh","doi":"10.1007/s10714-025-03405-1","DOIUrl":"10.1007/s10714-025-03405-1","url":null,"abstract":"<div><p>Neutron stars (NSs), superdense objects with exceptionally strong gravitational fields, provide an ideal laboratory for probing general relativity (GR) in the high-curvature regime. They also present an exciting opportunity to explore new gravitational physics beyond the traditional framework of GR. Thus, investigating modified theories of gravity in the context of superdense stars is intriguing and essential for advancing our understanding of gravitational phenomena in extreme environments. energy-momentum squared gravity (EMSG) is a modified theory of gravity that extends GR by including nonlinear terms involving the energy-momentum tensor <span>(T_{mu nu })</span>. EMSG and GR are indistinguishable in local tests like Solar System experiments, as both yield identical gravitational potentials, parametrized post-Newtonian (PPN) parameters, and geodesic motion in the weak-field regime. Therefore, detecting EMSG effects requires alternative approaches, such as NS observations in strong-field gravity. In this study, we examine the effects of EMSG on the properties and behaviour of NSs by varying the free parameter <span>(alpha )</span>. The hydrostatic equilibrium equations in the EMSG framework are derived and solved numerically to obtain mass-radius relations for soft, stiff, and intermediate equations of state (EOS). Observational measurements of NS masses and radii are used to constrain the fundamental-mode (<i>f</i>-mode) oscillation frequency through its universal relation with the tidal Love number and compactness. Results indicate that the stiff EOS undergoes a phase transition at the highest energy densities and pressures, followed by the intermediate and soft EOSs, highlighting the distinctive characteristics of these models. We also study the impact of EOS choice on the sound speed profile of NSs, reaffirming the physical validity of the models across the different <span>(alpha )</span> values.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 4","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143835743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analysis of the cosmological evolution parameters, energy conditions, and linear matter perturbations of an exponential-type model in f(Q) gravity f(Q)重力下指数型模型的宇宙学演化参数、能量条件和线性物质扰动分析

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-04-11 DOI: 10.1007/s10714-025-03403-3

Ivan R. Vasquez, A. Oliveros

{"title":"Analysis of the cosmological evolution parameters, energy conditions, and linear matter perturbations of an exponential-type model in f(Q) gravity","authors":"Ivan R. Vasquez, A. Oliveros","doi":"10.1007/s10714-025-03403-3","DOIUrl":"10.1007/s10714-025-03403-3","url":null,"abstract":"<div><p>We analytically study cosmological evolution in a flat FLRW spacetime in the context of modified STEGR gravity or <i>f</i>(<i>Q</i>), using an exponential two-parameter model which represents a smooth perturbative expansion around the <span>(Lambda )</span>CDM model. The cosmological analysis is carried out by calculating the Hubble parameter as a function of redshift, for selected values of the parameters. The Hubble parameter is obtained analytically by means of several approximations good enough to deviate slightly from the numerical solution. Several late-time cosmological parameters are computed, such as dark energy state parameter, deceleration parameter, and statefinder parameters. Additionally, we analyzed the behavior of the classical energy conditions WEC, SEC, NEC, and DEC for both the combination of matter and geometrical contribution and the geometrical contribution alone. Beyond the background level, linear matter perturbations are studied by calculating parameters relevant to structure growth and formation. The overall results indicate that the model may exhibit quintessence-like and phantom-like behavior and it also impacts the growth of structures in the universe by means late-time contributions to clustering.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 4","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Agegraphic dark energy with fractional entropy: Implications for cosmological evolution 分数熵的年龄暗能量：对宇宙演化的启示

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-04-11 DOI: 10.1007/s10714-025-03401-5

Muhammad Naeem, Aysha Bibi

{"title":"Agegraphic dark energy with fractional entropy: Implications for cosmological evolution","authors":"Muhammad Naeem, Aysha Bibi","doi":"10.1007/s10714-025-03401-5","DOIUrl":"10.1007/s10714-025-03401-5","url":null,"abstract":"<div><p>This work revisits the agegraphic dark energy (ADE) model by associating fractional entropy with the apparent horizon. This reveals the extent to which quantum-gravitational effects deform the horizon. The thermodynamic-gravity conjecture modifies the entropy expression, leading to changes in the energy density of ADE and the Friedmann equations. Based on this relationship, we have utilized modified fractional cosmology to investigate the cosmological implications of ADE and demonstrate how the exponent <span>(delta )</span> affects the evolution of cosmic parameters. Depending on the value of <span>(delta )</span>, the equation of state (EoS) parameter <span>(omega _{text {DE}})</span> make transition from the quintessence range (<span>(-1< omega _{text {DE}} < -1/3)</span>) to the phantom regime <span>((omega _{text {DE}} < -1))</span>, resulting in a shift from early deceleration to late time acceleration. Furthermore, the stability, theoretical and observational analyses of both the old and the new ADE models are discussed. All ADE results are reproduced in standard cosmology when <span>(delta = 2)</span>.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 4","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143822016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the detectability of gravitational waves emitted from head-on collisions of (ell )-boson stars 关于$$ell $$ -玻色子恒星正面碰撞发出的引力波的可探测性

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-04-11 DOI: 10.1007/s10714-025-03397-y

Mariana Lira, Laura O. Villegas, Javier M. Antelis, Víctor Jaramillo, Claudia Moreno, Darío Núñez

引用次数: 0