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.     

Dark Energy Accretion onto Van der Waal's Black Hole

We consider the most general static spherically symmetric black hole metric. The accretion of the fluid flow around the Van der Waal's black hole is investigated and we calculate the fluid's four-velocity, the critical point and the speed of sound during the accretion process. We also analyze the nature of the universe's density and the mass of the black hole during accretion of the fluid flow. The density of the fluid flow is also taken into account. We observe that the mass is related to redshift. We compare the accreting power of the Van der Waal's black hole with Schwarzschild black hole for different accreting fluid.     

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.     

Effects of Lorentz Breaking on the Accretion onto a Schwarzschild-like Black Hole

We formulate and solve the problem of spherically symmetric, steady state, adiabatic accretion onto a Schwarzschild-like black hole obtained recently. We derive the general analytic expressions for the critical points, the critical velocity, the critical speed of sound, and subsequently the mass accretion rate. The case for polytropic gas is discussed in detail. We find the parameter characterizing the breaking of Lorentz symmetry will slow down the mass accretion rate, while has no effect on the gas compression and the temperature profile below the critical radius and at the event horizon.     

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.     

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.     

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.     

Entropy Quantization of Schwarzschild Black Hole

The surface gravity of Schwarzschild black hole can be quantized from the test particle moving around different energy states analog to the Bohr's atomic model. We have quantized the Hawking temperature and entropy of Schwarzschild black hole from quantization of surface gravity. We also have shown that the change of entropy reduces to zero when the boundary shrinks to very small size.     

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.     

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.     

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...     

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.