scholarly journals Near-$$AdS_2$$ perturbations and the connection with near-extreme Reissner–Nordstrom

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
Achilleas P. Porfyriadis

Abstract The geometry very near the horizon of a near-extreme Reissner–Nordstrom black hole is described by the direct product of a near-$$AdS_2$$AdS2 spacetime with a two-sphere. While near-$$AdS_2$$AdS2 is locally diffeomorphic to $$AdS_2$$AdS2 the two connect differently with the asymptotically flat part of the geometry of (near-)extreme Reissner–Nordstrom. In previous work, we solved analytically the coupled gravitational and electromagnetic perturbation equations of $$AdS_2\times S^2$$AdS2×S2 and the associated connection problem with extreme Reissner–Nordstrom. In this paper, we give the solution for perturbations of near-$$AdS_2\times S^2$$AdS2×S2 and make the connection with near-extreme Reissner–Nordstrom. Our results here may also be thought of as computing the classical scattering matrix for gravitational and electromagnetic waves which probe the region very near the horizon of a highly charged spherically symmetric black hole.

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Shahar Hadar ◽  
Alexandru Lupsasca ◽  
Achilleas P. Porfyriadis

Abstract We study the SL(2) transformation properties of spherically symmetric perturbations of the Bertotti-Robinson universe and identify an invariant μ that characterizes the backreaction of these linear solutions. The only backreaction allowed by Birkhoff’s theorem is one that destroys the AdS2× S2 boundary and builds the exterior of an asymptotically flat Reissner-Nordström black hole with $$ Q=M\sqrt{1-\mu /4} $$ Q = M 1 − μ / 4 . We call such backreaction with boundary condition change an anabasis. We show that the addition of linear anabasis perturbations to Bertotti-Robinson may be thought of as a boundary condition that defines a connected AdS2×S2. The connected AdS2 is a nearly-AdS2 with its SL(2) broken appropriately for it to maintain connection to the asymptotically flat region of Reissner-Nordström. We perform a backreaction calculation with matter in the connected AdS2× S2 and show that it correctly captures the dynamics of the asymptotically flat black hole.


Entropy ◽  
2020 ◽  
Vol 22 (11) ◽  
pp. 1246
Author(s):  
Chenrui Zhu ◽  
Rong-Jia Yang

We consider whether the new horizon-first law works in higher-dimensional f(R) theory. We firstly obtain the general formulas to calculate the entropy and the energy of a general spherically-symmetric black hole in D-dimensional f(R) theory. For applications, we compute the entropies and the energies of some black hokes in some interesting higher-dimensional f(R) theories.


2019 ◽  
Vol 20 (9) ◽  
pp. 3059-3090 ◽  
Author(s):  
João L. Costa ◽  
José Natário ◽  
Pedro Oliveira

2014 ◽  
Vol 29 (36) ◽  
pp. 1450191 ◽  
Author(s):  
Xiao-Xiong Zeng ◽  
Qiang Li ◽  
Yi-Wen Han

Using exclusively an action variable, we quantize a static, spherically symmetric black hole. The spacings of the quantized entropy spectrum and area spectrum are found to be equal to the values given by Bekenstein. Interestingly, we find the spectra are independent of the hairs of the black holes and the mode of motion of a particle outside the spacetime, which depends only on the intrinsic properties of the gravity. Our result shows that the spectra are universal provided the spacetime owns a horizon.


2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Alexander Y. Yosifov ◽  
Lachezar G. Filipov

We argue that certain nonviolent local quantum field theory (LQFT) modification considered at the global horizon (r=2M) of a static spherically symmetric black hole can lead to adiabatic leakage of quantum information in the form of Hawking particles. The source of the modification is (i) smooth at r=2M and (ii) rapidly vanishing at r≫2M. Furthermore, we restore the unitary evolution by introducing extra quanta which departs slightly from the generic Hawking emission without changing the experience of an infalling observer (no drama). Also, we suggest that a possible interpretation of the Bekenstein-Hawking bound as entanglement entropy may yield a nonsingular dynamical horizon behavior described by black hole thermodynamics. Hence, by treating gravity as a field theory and considering its coupling to the matter fields in the Minkowski vacuum, we derive the conjectured fluctuations of the background geometry of a black hole.


2014 ◽  
Vol 29 (02) ◽  
pp. 1450010 ◽  
Author(s):  
S. MIGNEMI

We present a technique for obtaining exact spherically symmetric asymptotically de Sitter (dS) or anti-de Sitter (adS) black hole solutions of dilaton gravity with generic coupling to Maxwell field, starting from asymptotically flat solutions and adding a suitable dilaton potential to the action.


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