Phantom Accretion onto the Schwarzschild Anti de-Sitter Black Hole

In this paper we study phantom energy accretion onto the Schwarzschild anti de-Sitter black hole. We obtain critical point where the speed of flow is equal speed of sound. We find that the critical point is near the black hole horizon.     

Accretion of Phantom Energy by Bardeen Black Hole

In this paper we deal with the accretion of phantom energy onto static spherically symmetric Bardeen black hole. It is shown that the mass of black hole reduces with the accretion of phantom energy. We compute accretion rate onto Bardeen black hole at critical point. Furthermore, we obtain the conditions at critical point, under which accretion is possible and also discuss certain relevant cases. Finally, we discuss the validity of generalized second law of thermodynamics at the event horizon of Bardeen black hole.     

Accretion onto the Magnetically Charged Regular Black Hole

We investigate the accretion process for static spherically symmetric geometry, i.e., magnetically charged regular black hole with isotropic fluid. We obtain generalized expressions for the velocity(u(r)), speed of sound(c_s~2),energy density(ρ(r)) and accretion rate(M) at the critical point near the regular black hole during the accretion process. We also plot these physical parameters against fixed values of charge, mass and different values of equation of state parameter to study the process of accretion. We find that radial velocity and energy density of the fluid remain positive and negative as well as rate of change of mass is increased and decreased for dust, stiff,quintessence fluid and phantom-like fluid, respectively.     

Massive Particle＇s Tunnelling from Black Hole with Topological Defect

We extend Zhang and Zhao＇s recent work to black hole with topological defect whose Arnowitt-Deser-Misner mass is no longer identical to its mass parameter. The behaviour of the tunnelling massive particles is investigated, and the emission rate at which massive particles tunnel across the event horizon of the black hole is calculated. The result is consistent with an underlying unitary theory, and takes the same functional form as that of mass-less particles.     

Nucleosynthesis in Advection-Dominated Accretion Flow onto a Black Hole

Nucleosynthesis in advection-dominated accretion flow(ADAF) onto a black hole is proposed to be an important role in chemical evolution around compact stars. We investigate the nucleosynthesis in ADAF relevant for a black hole of low mass,different from that of the self-similar solution. in particular,the presence of supersolar metal mass fractions of some isotopes seems to be associated with the known black hole nucleosynthesis in ADAF,which offers further evidence of diversity of the chemical enrichment.     

Dark Energy Accretion onto a Black Hole in an Expanding Universe

By using the solution describing a black hole embedded in the FLRW universe, we obtain the evolving equation of the black hole mass expressed in terms of the cosmological parameters. The evolving equation indicates that in the phantom dark energy universe the black hole mass becomes zero before the Big Rip is reached.     

Quantum Corrections to the Radiation of Schwarzschild-anti-de Sitter Black Hole with Topological Defect

We extend Zhang and Zhao＇s recent work to the Schwarzschild-anti-de Sitter black hole with topological defect, whose Arnowitt-Deser-Misner （ADM） mass is no longer identical to its mass parameter. The behavior of the tunneling massive particle is investigated and the emission rate is calculated. The result satisfies an underlying unitary theory and takes the same functional form as that of the mass-less particle.     

Harrison Metrics for the Schwarzschild Black Hole

Based on the hidden conformed symmetry, some authors have proposed a Harrison metric for the Schwarzschild black hole. We give a procedure which can generate a family of Harrison metrics starting from a general set of SL（2, R） vector fields. By analogy with the subtracted geometry of the Kerr black hole, we find a new Harrison metric for the Schwaxzschild case. its conformal generators axe also investigated using the Killing equations in the near-horizon limit.     

Quantization of the Interior Schwarzschild Black Hole

We study a Hamiltonian quantum formalism of a spherically symmetric space-time which can be identified with the interior of a Schwarzschild black hole. The phase space of this model is spanned by two dynamical variables and their conjugate momenta. It is shown that the classical Lagrangian of the model gives rise the interior metric of a Schwarzschild black hole. We also show that the mass of such a system is a Dirac observable and then by quantization of the model by Wheeler-DeWitt approach and constructing suitable wave packets we get the mass spectrum of the black hole.     

Quantum Tunnelling and Hawking Radiation of Schwarzchild-Anti-de Sitter Black Hole with Topological Defect

We extend Parikh＇s recent work to Schwarzchild-anti-de Sitter black hole with topological defect whose Arnowitt-Deser-Misner （ADM） mass is no longer identical to its mass parameter. We view the Hawking radiation as a tunnelling process across the event horizon and the cosmological horizon. From the tunnelling probability, we find a leading correction to the semi-classical emission rate. The result employs an underlying unitary theory.     

Schwarzschild Black Hole as a Particle Accelerator

JETP Letters - We consider collision of two particles near the horizon of a nonextremal static black hole. At least one of them is accelerated. We show that the center-of-mass energy Ecm can become...     

Interior of a Schwarzschild Black Hole Revisited

The Schwarzschild solution has played a fundamental conceptual role in general relativity, and beyond, for instance, regarding event horizons, spacetime singularities and aspects of quantum field theory in curved spacetimes. However, one still encounters the existence of misconceptions and a certain ambiguity inherent in the Schwarzschild solution in the literature. By taking into account the point of view of an observer in the interior of the event horizon, one verifies that new conceptual difficulties arise. In this work, besides providing a very brief pedagogical review, we further analyze the interior Schwarzschild black hole solution. Firstly, by deducing the interior metric by considering time-dependent metric coefficients, the interior region is analyzed without the prejudices inherited from the exterior geometry. We also pay close attention to several respective cosmological interpretations, and briefly address some of the difficulties associated to spacetime singularities. Secondly, we deduce the conserved quantities of null and timelike geodesics, and discuss several particular cases in some detail. Thirdly, we examine the Eddington–Finkelstein and Kruskal coordinates directly from the interior solution. In concluding, it is important to emphasize that the interior structure of realistic black holes has not been satisfactorily determined, and is still open to considerable debate.     

Topology in Entropy of Schwarzschild Black Hole

In the light of -mapping method and the relationship between the entropy and the Euler characteristic, the inner topological structure of the entropy of Schwarzschild black hole is studied. By introducing an entropy density, it is shown that the entropy of Schwarzschild black hole is determined by the singularities of the timelike Killing vector field of spacetime and these singularities carry the topological numbers, Hopf indices and Brouwer degrees, naturally. Taking account of the statistical meaning of entropy in physics, the entropy of Schwarzschild black hole is merely the sum of the Hopf indices, which will give the increasing law of entropy of black holes.     

Strichartz Estimates on Schwarzschild Black Hole Backgrounds

We study dispersive properties for the wave equation in the Schwarzschild space-time. The first result we obtain is a local energy estimate. This is then used, following the spirit of [29], to establish global-in-time Strichartz estimates. A considerable part of the paper is devoted to a precise analysis of solutions near the trapping region, namely the photon sphere.     

Possibility of Cyclic Turnarounds in Brane-World Scenario: Phantom Energy Accretion onto Black Holes and Its Consequences

A universe described by braneworlds is studied in a cyclic scenario. As expected such an oscillating universe will undergo turnarounds, whenever the phantom energy density reaches a critical value from either side. It is found that a universe described by RSII brane model will readily undergo oscillations if, either the brane tension, λ or the bulk cosmological constant, Λ ₄ is negative. The DGP brane model does not readily undergo cyclic turnarounds. Hence for this model a modified equation is proposed to incorporate the cyclic nature. It is found that there is always a remanent mass of a black hole at the verge of a turnaround. Hence contrary to known results in literature, it is found that the destruction of black holes at the turnaround is completely out of question. Finally to alleviate, if not solve, the problem posed by the black holes, it is argued that the remanent masses of the black holes do not act as a serious defect of the model because of Hawking evaporation.     

Holographic Superconductor of Regular Phantom Black Hole

Holographic superconductors containing a non-minimal derivative coupling for the scalar field in a regular phantom plane symmetric black hole have been considered. We show that the parameter of the regular black hole b as well as the non-minimal derivative coupling parameter η affect the formation of the condensate as well as the conductivity in the superconductor. Moreover, b has a critical value in which the critical temperature T_c increases without a bound.     

Quintessence Contribution to a Schwarzschild Black Hole Entropy

The quintessence contribution to a Schwarzschild black hole entropy is thoroughly investigated by using the improved brick-wall model. It is found that due to the present of the quintessence, there are two horizons, one is the cosmological horizon, and the other is the black hole horizon. By regulating the cut-off factor ε and the thickness of the thin layer 5, we obtain that the entropy of the system is 1/4 of the sum of the areas of the two event horizons.