General Relativity and Gravitation最新文献_第4页

Slowly rotating and charged black-holes in entangled relativity

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-02-04 DOI: 10.1007/s10714-025-03366-5

Maxime Wavasseur, Théo Abrial, Olivier Minazzoli

引用次数: 0

Periodic orbits of neutral test particles in Reissner–Nordström naked singularities

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-02-04 DOI: 10.1007/s10714-025-03368-3

Zoe C. S. Chan, Yen-Kheng Lim

{"title":"Periodic orbits of neutral test particles in Reissner–Nordström naked singularities","authors":"Zoe C. S. Chan, Yen-Kheng Lim","doi":"10.1007/s10714-025-03368-3","DOIUrl":"10.1007/s10714-025-03368-3","url":null,"abstract":"<div><p>We conduct studies on Levin’s taxonomy of periodic orbits for neutral test particles around a Reissner-Nordström naked singularity. It was known that naked singularities could harbor two distinct regions of time-like bound orbits and thus we expect periodic orbits to appear in both regions. It is possible for a pair of periodic orbits from both regions to possess the exact same angular momentum <i>L</i> and energy <i>E</i> values. We chart the sets of periodic orbits in (<i>L</i>, <i>E</i>)-parameter space and highlight the general distribution pattern of these sets for three possible scenarios. Regions within (<i>L</i>, <i>E</i>)-space can be partitioned into multiple domains <span>({mathcal {D}}_k)</span> based on the roots configuration of the quartic polynomial <i>P</i>(<i>u</i>) where <i>u</i> is the inverse radial coordinate. Consequently, each domain and interestingly enough, portions of certain periodic orbits sets that lie in different <span>({mathcal {D}}_k)</span> require different analytical solutions to plot the resulting orbit. Furthermore, we uncover physical properties of some hypothetical circular orbits residing in the inner region from analysing the (<i>L</i>, <i>E</i>)-space.\u0000</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 2","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143107941","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

Taming the classically divergent curvature in self-adjoint quantum black holes

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-02-03 DOI: 10.1007/s10714-025-03373-6

Harpreet Singh, Malay K. Nandy

{"title":"Taming the classically divergent curvature in self-adjoint quantum black holes","authors":"Harpreet Singh, Malay K. Nandy","doi":"10.1007/s10714-025-03373-6","DOIUrl":"10.1007/s10714-025-03373-6","url":null,"abstract":"<div><p>It is well-known that the Kretschmann curvature diverges strongly at the classical singularity of the black hole interior. In this paper, we are therefore interested in whether such a strong divergence can be tamed quantum mechanically in the vicinity of the black hole singularity. For this purpose, we consider DeWitt-regular quantum black hole solutions of a self-adjoint Wheeler–DeWitt equation originating from a Kantowski-Sachs representation of the black hole interior, coupled with a Klein–Gordon field that accounts for the existence of zero-point quantum vacuum fluctuations. We find that there exist regular quantum black holes with self-adjoint Hamiltonians having well-behaved Kretschmann curvature in the vicinity of the singularity, tamed by stronger restrictions on the eigenvalues than ones required by the DeWitt boundary condition. Consequently, the Kretschmann-regular black holes are found in smaller but still infinite domains in the space of eigenvalues allowed by the DeWitt criterion. Furthermore, we find that other relevant classically diverging quantities pose no threat as their quantum mechanical counterparts are well-behaved in the vicinity of the singularity.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 2","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143083898","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

Geometry from geodesics: fine-tuning Ehlers, Pirani, and Schild

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-02-02 DOI: 10.1007/s10714-025-03355-8

James T. Wheeler

{"title":"Geometry from geodesics: fine-tuning Ehlers, Pirani, and Schild","authors":"James T. Wheeler","doi":"10.1007/s10714-025-03355-8","DOIUrl":"10.1007/s10714-025-03355-8","url":null,"abstract":"<div><p>Ehlers, Pirani, and Schild argued that measurements of null and timelike geodesics yield Weyl and projective connections, respectively, with compatibility in the lightlike limit giving an integrable Weyl connection. Their conclusions hold only for a 4-dim representation of the conformal connection on the null cone, and by restricting reparameterizations of timelike geodesics to yield a torsion-free, affine connection. An arbitrary connection gives greater freedom. A linear connection for the conformal symmetry of null geodesics requires the SO(4,2) representation. The enlarged class of projective transformations of timelike geodesics changes Weyl’s projective curvature, and we find invariant forms of the torsion and nonmetricity, along with a new, invariant, second rank tensor field generalizing the dilatational curvature without requiring a metric. We show that either projective or conformal connections require a monotonic, twice differentiable function on a spacetime region foliated by order isomorphic, totally ordered, twice differentiable timelike curves in a necessarily Lorentzian geometry. We prove that the conditions for projective and conformal Ricci flatness imply each other and gauge choices within either can reduce the geometry to the original Riemannian form. Thus, measurements of null and timelike geodesics lead to an SO(4,2) connection, with no requirement for a lightlike limit. Reduction to integrable Weyl symmetry can only follow from the field equations of a gravity theory. We show that the simplest quadratic spacetime action leads to this reduction.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 2","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10714-025-03355-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077490","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

The backreaction problem for black holes in semiclassical gravity

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-02-01 DOI: 10.1007/s10714-025-03352-x

Adrian del Rio

引用次数: 0

Lorentzian Robin Universe of Gauss-Bonnet Gravity

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-01-31 DOI: 10.1007/s10714-025-03369-2

Manishankar Ailiga, Shubhashis Mallik, Gaurav Narain

{"title":"Lorentzian Robin Universe of Gauss-Bonnet Gravity","authors":"Manishankar Ailiga, Shubhashis Mallik, Gaurav Narain","doi":"10.1007/s10714-025-03369-2","DOIUrl":"10.1007/s10714-025-03369-2","url":null,"abstract":"<div><p>The gravitational path-integral of Gauss–Bonnet gravity is investigated and the transition from one spacelike boundary configuration to another is analyzed. Of particular interest is the case of Neumann and Robin boundary conditions which is known to lead to a stable Universe in Einstein–Hilbert gravity in four spacetime dimensions. After setting up the variational problem and computing the necessary boundary terms, the transition amplitude is computed <i>exactly</i> in the mini-superspace approximation. The <span>(hbar rightarrow 0)</span> limit brings out the dominant pieces in the path-integral which is traced to an initial configuration corresponding to Hartle–Hawking no-boundary Universe. A deeper study involving Picard–Lefschetz methods not only allow us to find the integration contour along which the path-integral becomes convergent but also aids in understanding the crossover from Euclidean to Lorentzian signature. Saddle analysis further highlights the boundary configurations giving dominant contribution to the path-integral which is seen to be those corresponding to Hartle–Hawking no-boundary proposal and agrees with the exact computation. To ensure completeness, a comparison with the results from Wheeler–DeWitt equation is done.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 2","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071350","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

Dynamics of redshift/blueshift during free fall under the Schwarzschild horizon

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-01-31 DOI: 10.1007/s10714-025-03370-9

H. V. Ovcharenko, O. B. Zaslavskii

引用次数: 0

Gravitational reduction of the wave function through the quantum theory of motion

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-01-29 DOI: 10.1007/s10714-025-03365-6

Faramarz Rahmani

引用次数: 0

Quantum theory of the Lemaître model for gravitational collapse

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-01-28 DOI: 10.1007/s10714-025-03349-6

Claus Kiefer, Hamid Mohaddes

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Quantum black holes: from regularization to information paradoxes

IF 2.1 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2025-01-24 DOI: 10.1007/s10714-025-03356-7

Niayesh Afshordi, Stefano Liberati

引用次数: 0