We consider static non-extremal charged black hole solutions in the context of N = 2 gauged supergravity theories in five dimensions, and we show that they satisfy first-order flow equations. Then we analyze the motion of the dual brane in these black hole backgrounds. We express the entropy in terms of a Cardy-Verlinde-type formula, and we show that the equations describing the FRW cosmology o...

In the four-dimensional spacetime, when the two-sphere of black hole event horizons is replaced by a two-dimensional hypersurface with zero or negative constant curvature, the black hole is referred as to a topological black hole. In this paper we present some exact topological black hole solutions in the Einstein-Maxwell-dilaton theory with a Liouville-type dilaton potential. PACS numbers: 04....

We present a static solution for d = 2 critical string theory including the tachyon T but not its potential V (T ). This solution thus incorporates tachyon back reaction and, when T = 0, reduces to the black hole solution. When T 6= 0 one finds that (1) the Schwarzschild horizon of the above black hole splits into two, resembling Reissner-Nordstrom horizons and (2) the curvature scalar develops...

No analytic solution is known to date for a black hole in a compact dimension. We develop an analytic perturbation theory where the small parameter is the size of the black hole relative to the size of the compact dimension. We set up a general procedure for an arbitrary order in the perturbation series based on an asymptotic matched expansion between two coordinate patches: the near horizon zo...

The phenomenon of string spreading on the black hole horizon, as originally discussed by Susskind, is considered in the exact curved Schwarzschild background. We consider an oscillating string encircling the black hole and contracting towards the horizon. We then compute the angular and radial spreading of the string, as seen by a static observer at spatial infinity using fixed finite resolutio...

We investigate the accretion process for different spherically symmetric space-time geometries for a static fluid. We analyze this procedure using the most general black hole metric ansatz. After that, we examine the accretion process for specific spherically symmetric metrics obtaining the velocity of the sound during the process and the critical speed of the flow of the fluid around the black...

We consider for j = 1 2 , 3 2 , . . . a spherically symmetric, static system of (2j + 1) Dirac particles, each having total angular momentum j. The Dirac particles interact via a classical gravitational and electromagnetic field. The Einstein-Dirac-Maxwell equations for this system are derived. It is shown that, under weak regularity conditions on the form of the horizon, the only black hole so...

We consider for j = 1 2 ; 3 2 ; : : : a spherically symmetric, static system of (2j + 1) Dirac particles, each having total angular momentum j. The Dirac particles interact via a classical gravitational and electromagnetic eld. The Einstein-Dirac-Maxwell equations for this system are derived. It is shown that, under weak regularity conditions on the form of the horizon, the only black hole solu...

We discuss the graviton absorption probability (greybody factor) and the cross-section of a higherdimensional Schwarzschild black hole (BH). We are motivated by the suggestion that a great many BHs may be produced at the LHC and bearing this fact in mind, for simplicity, we shall investigate the intermediate energy regime for a static Schwarzschild BH. That is, for (2M)ω ∼ 1, where M is the mas...

The “screen mapping” introduced by Susskind to implement ’t Hooft’s holographic hypothesis is studied. For a single screen time, there are an infinite number of images of a black hole event horizon, almost all of which have smaller area on the screen than the horizon area. This is consistent with the focusing equation because of the existence of focal points. However, the boundary of the past (...