Near horizon OTT black hole asymptotic symmetries and soft hair

We study the near horizon geometry of both static and stationary extremal Oliva Tempo Troncoso(OTT)black holes. For each of these cases, a set of consistent asymptotic conditions is introduced. The canonical generator for the static configuration is shown to be regular. For the rotating OTT black hole, the asymptotic symmetry is described by the time reparametrization, the chiral Virasoro and centrally extended u(1) Kac-Moody algebras.     

On tunneling through the black hole horizon

It is shown here that there is no way for particle creation to occur by quantum tunneling through an infinitesimal neighborhood of the black hole horizon. This result is a trivial consequence of the regularity of the horizon, the equivalence principle and the general covariance of the relativistic theory of gravity. Moreover, we also confirm the less trivial statement that no particle creation by quantum tunneling through the black hole horizon is possible independent of the size of the presupposed tunneling domain.     

Schwarzschild generalized black hole horizon and the embedding space

The European Physical Journal C - By performing a Taylor expansion along the extra dimension of a metric describing a black hole on a brane, we explore the influence of the embedding space on the...     

A jet appearing when a black hole event horizon touches the rindler horizon

The Hawking effect of a nonuniformly rectilinearly accelerating Kinnersley black hole is studied. Its horizons are rotationally symmetric. Its Hawking temperature depends not only on the time, but also on the polar angle. When a Kinnersley black hole touches its Rindler horizon, the Hawking temperature at the contact point is reduced to zero. But at the opposite pole of the black hole, the Hawking temperature increases rapidly. A jet appears as a tail of the accelerating black hole.     

Area spectrum of horizon and black hole entropy

The European Physical Journal C - A Mathematica package for color summed calculations in QCD (SU(N c )) is presented. Color contractions of any color amplitude appearing in QCD may be performed,...     

Particle tunnels across the horizon of Garfinkle-Horowitz-Strominger dilaton black hole

We promote the work of Parikh and Wilczek on the black hole radiation to the emission of massive and charged particles from Garfinkle-Horowitz-Strominger black hole. The energy and charge of the space-time are conservational during the course of the evaporation. The calculation shows that the emission spectrum is not precisely thermal, while has a correction, and the conclusion supports the viewpoint of information conservation.     

Sound horizon of accretion onto a Kerr black hole

Two accretion modes (disclike and Bondi type), based on a discontinuous change in location of the sound horizon, exist generally for accretion onto a Kerr black hole, except for the case of a corotating accretion flow onto a very rapidly rotating hole, in which only Bondi-type mode is possible.     

Conformal field theory on the horizon of a BTZ black hole

In a three-dimensional spacetime with negative cosmological constant, general relativity can be written as two copies of SO(2,1) Chern-Simons theory. On a manifold with a boundary, the Chern-Simons theory induces a conformal field theory—Wess-Zumino-Witten theory on the boundary. In this paper, it is shown that with suitable boundary conditions for a Banados-Teitelboim-Zanelli black hole, the Wess-Zumino-Witten theory can reduce to a chiral massless scalar field on the horizon.     

The string spectrum on the horizon of a non-extremal black hole

We investigate the conformal string σ-model corresponding to a general five-dimensional non-extremal black hole solution. In the horizon region the theory reduces to an exactly solvable conformal field theory. We determine the modular invariant spectrum of physical string states, which expresses the Rindler momentum operator in terms of three charges and string oscillators. For black holes with winding and Kaluza-Klein charges, we find that states made with only right-moving excitations have ADM mass equal to the black hole ADM mass, and thus they can be used as sources of the gravitational field. A discussion on statistical entropy is included.     

Instability of black hole horizon with respect to electromagnetic excitations

Analyzing exact solutions of the Einstein–Maxwell equations in the Kerr–Schild formalism we show that black hole horizon is instable with respect to electromagnetic excitations. Contrary to perturbative smooth harmonic solutions, the exact solutions for electromagnetic excitations on the Kerr background are accompanied by singular beams which have very strong back reaction to metric and break the horizon, forming the holes which allow radiation to escape interior of black-hole. As a result, even the weak vacuum fluctuations break the horizon topologically, covering it by a set of fluctuating microholes. We conclude with a series of nontrivial consequences, one of which is that there is no information loss inside of black-hole.     

Recovering information borne by quanta that crossed the black hole event horizon

In this essay we discuss how the statistics of quantum particles, namely, stimulated emission for bosons and the exclusion principle for fermions, provide mechanisms for correlating the radiations impinging and emanating from a black hole. In either case, the information originally borne by the incoming radiation that is partially transferred to the outging radiation is estimated within the framework of communication theory.     

The region interior to the event horizon of the regular Hayward black hole

The Painlevé–Gullstrand coordinates allow us to explore the interior of the regular Hayward black hole. The behavior of an infalling particle in traversing the Hayward black hole is compared with the one inside the Schwarzschild and Reissner–Nordstrom singular black holes. When approaching the origin the test particle trajectories present differences depending if the center is regular or singular. The velocities of the infalling test particle into the modified Hayward black hole are analyzed as well. As compared with the normal Hayward, in the modified Hayward black hole the particle moves faster and the surface gravity is smaller.