arXiv: General Relativity and Quantum Cosmology最新文献

Quantum optics meets black hole thermodynamics via conformal quantum mechanics: I. Master equation for acceleration radiation 量子光学通过共形量子力学满足黑洞热力学:1 .加速辐射的主方程

arXiv: General Relativity and Quantum Cosmology Pub Date : 2021-08-17 DOI: 10.1103/PhysRevD.104.084086

A. Azizi, H. Camblong, A. Chakraborty, C. Ordóñez, M. Scully

引用次数: 4

Balancing Static Vacuum Black Holes with Signed Masses in 4 and 5 Dimensions 平衡4维和5维有符号质量的静态真空黑洞

arXiv: General Relativity and Quantum Cosmology Pub Date : 2021-05-27 DOI: 10.1103/PhysRevD.104.044063

M. Khuri, G. Weinstein, S. Yamada

{"title":"Balancing Static Vacuum Black Holes with Signed Masses in 4 and 5 Dimensions","authors":"M. Khuri, G. Weinstein, S. Yamada","doi":"10.1103/PhysRevD.104.044063","DOIUrl":"https://doi.org/10.1103/PhysRevD.104.044063","url":null,"abstract":"We construct a new set of asymptotically flat, static vacuum solutions to the Einstein equations in dimensions 4 and 5, which may be interpreted as a superposition of positive and negative mass black holes. The resulting spacetimes are axisymmetric in 4-dimensions and bi-axisymmetric in 5-dimensions, and are regular away from the negative mass singularities, for instance conical singularities are absent along the axes. In 5-dimensions, the topologies of signed mass black holes used in the construction may be either spheres $S^3$ or rings $S^1 times S^2$; in particular, the negative mass static black ring solution is introduced. A primary observation that facilitates the superposition is the fact that, in Weyl-Papapetrou coordinates, negative mass singularities arise as overlapping singular support for a particular type of Green's function. Furthermore, a careful analysis of conical singularities along axes is performed, and formulas are obtained for their propagation across horizons, negative mass singularities, and corners. The methods are robust, and may be used to construct a multitude of further examples. Lastly, we show that balancing does not occur between any two signed mass black holes of the type studied here in 4 dimensions, while in 5 dimensions two-body balancing is possible.","PeriodicalId":8455,"journal":{"name":"arXiv: General Relativity and Quantum Cosmology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72742882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

A new proof of Geroch's theorem on temporal splitting of globally hyperbolic spacetime 关于全局双曲时空时间分裂的Geroch定理的新证明

arXiv: General Relativity and Quantum Cosmology Pub Date : 2021-03-01 DOI: 10.21203/RS.3.RS-229207/V1

A. Bleybel

引用次数: 0

Noncovariance of “covariant polymerization” in models of loop quantum gravity 环量子引力模型中“协变聚合”的非协方差

arXiv: General Relativity and Quantum Cosmology Pub Date : 2021-02-22 DOI: 10.1103/PhysRevD.103.126025

M. Bojowald

引用次数: 3

Strong field gravitational lensing by hairy Kerr black holes 毛状克尔黑洞的强场引力透镜效应

arXiv: General Relativity and Quantum Cosmology Pub Date : 2021-02-16 DOI: 10.1103/PhysRevD.103.124052

Shafqat Ul Islam, Sushant G. Ghosh

{"title":"Strong field gravitational lensing by hairy Kerr black holes","authors":"Shafqat Ul Islam, Sushant G. Ghosh","doi":"10.1103/PhysRevD.103.124052","DOIUrl":"https://doi.org/10.1103/PhysRevD.103.124052","url":null,"abstract":"The recent time witnessed a surge of interest in strong gravitational lensing by black holes due to the Event Horizon Telescope (EHT) results, suggesting comparing the black hole lensing in general relativity and modified gravity theories. That may help us to assess the phenomenological differences between these models. A Kerr black hole is also a solution to some alternative theories of gravity, while recently obtained modified Kerr black holes (hairy Kerr black holes), which evade the no-hair theorem, are due to additional sources the surrounding fluid, like dark matter, having conserved energy momentum tensor (EMT). These hairy Kerr black holes may be solutions to an alternative theory of gravity. We generalize previous work on gravitational lensing by a Kerr black hole, in the strong deflection limits to the hairy Kerr black holes, with deviation parameter $alpha$ and a primary hair $ell_0$. Interestingly, the deflection coefficient $bar{a}$, respectively, increases and decreases with increasing $ell_0$ and $alpha$. $bar{b}$ shows opposite behaviour with $ell_0$ and $alpha$. We also find that the deflection angle $alpha_D$, angular position $theta_{infty}$ and $u_{m}$ decreases, but angular separation $s$ increases with $alpha$. We compare our results with those for Kerr black holes, and also, the formalism is applied to discuss the astrophysical consequences in the context of the supermassive black holes Sgr A* and M87*. We observe that the deviations of the angular positions from that of the Kerr black hole are not more than $2.6~mu$as for Sgr A* and $1.96~mu$as for M87*, which are unlikely to get resolved by the current EHT observations.","PeriodicalId":8455,"journal":{"name":"arXiv: General Relativity and Quantum Cosmology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78130378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 14

Numerical investigation of the dynamics of linear spin s fields on a Kerr background. II. Superradiant scattering 克尔背景下线性自旋场动力学的数值研究。2超辐射散射

arXiv: General Relativity and Quantum Cosmology Pub Date : 2021-01-14 DOI: 10.1103/PHYSREVD.103.084035

K'aroly Csuk'as, I. R'acz

引用次数: 1

Summation by parts and truncation error matching on hyperboloidal slices 双曲面切片的部分求和与截断误差匹配

arXiv: General Relativity and Quantum Cosmology Pub Date : 2021-01-13 DOI: 10.1103/PHYSREVD.103.084045

Shalabh Gautam, Alex Van'o-Vinuales, D. Hilditch, S. Bose

{"title":"Summation by parts and truncation error matching on hyperboloidal slices","authors":"Shalabh Gautam, Alex Van'o-Vinuales, D. Hilditch, S. Bose","doi":"10.1103/PHYSREVD.103.084045","DOIUrl":"https://doi.org/10.1103/PHYSREVD.103.084045","url":null,"abstract":"We examine stability of summation by parts (SBP) numerical schemes that use hyperboloidal slices to include future null infinity in the computational domain. This inclusion serves to mitigate outer boundary effects and, in the future, will help reduce systematic errors in gravitational waveform extraction. We also study a setup with truncation error matching. Our SBP-Stable scheme guarantees energy-balance for a class of linear wave equations at the semidiscrete level. We develop also specialized dissipation operators. The whole construction is made at second order accuracy in spherical symmetry, but could be straightforwardly generalized to higher order or spectral accuracy without symmetry. In a practical implementation we evolve first a scalar field obeying the linear wave equation and observe, as expected, long term stability and norm convergence. We obtain similar results with a potential term. To examine the limitations of the approach we consider a massive field, whose equations of motion do not regularize, and whose dynamics near null infinity, which involve excited incoming pulses that can not be resolved by the code, is very different to that in the massless setting. We still observe excellent energy conservation, but convergence is not satisfactory. Overall our results suggest that compactified hyperboloidal slices are likely to be provably effective whenever the asymptotic solution space is close to that of the wave equation.","PeriodicalId":8455,"journal":{"name":"arXiv: General Relativity and Quantum Cosmology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77459509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Curved Space and Gravity 弯曲空间与重力

arXiv: General Relativity and Quantum Cosmology Pub Date : 2021-01-01 DOI: 10.1007/978-0-387-09534-9_15

R. Adler

引用次数: 0

Lorentz Transformations 洛伦兹变换

arXiv: General Relativity and Quantum Cosmology Pub Date : 2021-01-01 DOI: 10.1007/978-3-030-61574-1_2

R. Adler

引用次数: 0

Spherically Symmetric Gravitational Fields 球对称引力场

arXiv: General Relativity and Quantum Cosmology Pub Date : 2021-01-01 DOI: 10.1007/978-3-030-61574-1_9

R. Adler

引用次数: 0