This paper has been withdrawn by the authors, an improved version with the title "Exact Fermi coordinates for a class of spacetimes", arXiv:0912.2779, replaces it.
We analyze the scalar radiation emitted by a source in geodesic circular orbits around a Schwarzschild-de Sitter black hole. We obtain the emitted power using quantum field theory in curved spacetimes framework at tree level. We compare our results with the scalar synchrotron radiation in Schwarzschild spacetime.
We study a charged Taub-NUT spacetime solution in the DGP brane. We show that the Reissner-Nordstrom-Taub-NUT-de Sitter solution of Einstein-Maxwell gravity solves the corresponding equations of motion, where the cosmological constant is related to the cross-over scale in the DGP model. Following the approach by Teitelboim in discussing the thermodynamics of de Sitter spacetime and the proposal by Wu et al. for a conserved charge associated to the NUT parameter, we obtained the generalized Smarr mass formula and the first law of thermodynamics of the spacetime.
The causal properties of the family of Kerr-de Sitter spacetimes are analyzed and compared to those of the Kerr family. At first we show that a Kerr-de Sitter spacetime can be viewed as an assembly of Carter's blocks i.e. four dimensional spacetime regions contained within Killing horizons or a Killing horizon and the asymptotic de Sitter region. From this perspective and leaving aside topological identifications, the causal properties of a Kerr de Sitter spacetime are determined by the causal properties of the individual Carter's blocks viewed as spacetimes in their own right. We show that an…
We introduce a calculation, based on purely topological reasoning, of the global equilibrium Hawking temperature of the Schwarzschild-de Sitter spacetime, where a Schwarzschild black hole horizon coexists with a de Sitter cosmological horizon. Our method is based on the careful calculation of the Euler characteristic of the total system, showing that this quantity completely determines the thermodynamical features of the system. The method is universal and can be applied to any structure possessing multiple horizons in general relativity.
We start a systematic investigation of possible isometries of the asymptotically de Sitter solutions to Einstein equations. We reformulate the Killing equation as conformal equations for the initial data at $\mathcal{I}^+$. This allows for partial classification of possible symmetry algebras. In particular, if they are not maximal, they may be at most $4$-dimensional. We provide several examples. As a simple collorary it is shown that the only spacetime in which the Killing horizon intersects $\mathcal{I}^+$ (after a conformal completion) is locally the de Sitter universe.
We perform a Hadamard point-split renormalization of the current density $j_ν$ of a charged scalar field in a Reissner-Nordström-de Sitter spacetime. We compute numerically the expectation values of the components $j_r$ and $j_t$ in the Unruh state in the exterior region and study their dependence on the field parameters and the position.
Reply to [arXiv:1105.5653]: "Comment on 'Quasinormal modes in Schwarzschild-de Sitter spacetime: A simple derivation of the level spacing of the frequencies'"
我们解释了为什么我们的论文[Phys. Rev. D 69,064033(2004),arXiv:gr-qc/0311064 ]中的分析是相关和正确的。
The semiclassical stability of de Sitter spacetime
de Sitter时空和Bunch-Davies真空是描述时空几何演化的半经典爱因斯坦-薛定谔方程和具有任意曲率耦合的大质量标量量子场的解。通过计算de Sitter - Bunch-Davies系统的小空间均匀偏差的重整化能量动量张量期望值和求解线性化反反应问题,证明了该解的稳定性。重正化方案的开发。所有的动量积分都是解析地进行的。根据拉普拉斯变换给出了一般解。它只包含两个人为的不稳定性:一个恒定的规范模式和普朗克时间尺度上的不稳定性躺在我们的半经典理论的范围之外。
We establish the positive energy theorem for weak asymptotically anti-de Sitter initial data sets with distributional curvature under the weak dominant energy condition.
The deep reason why the equations describing axial and polar perturbations of Schwarzschild black holes have the same spectrum is far from trivial. In this article, we revisit the original proof and try to make it clearer. Still focusing on uncharged and non-rotating black holes, we extend the results to spacetimes including a cosmological constant, which have so far mostly been investigated numerically from this perspective.