Propagation and Evolution of a Scalar Field in Einstein-Power-Maxwell Spacetime

The propagation and dynamical evolution of a scalar field in the background of a(2+1)-dimensional Einstein–Power–Maxwell(EPM)black hole are studied.We obtain an analytical expression for the greybody factor,which shows that the greybody factor increases as the electric charge increases and approaches unity for large frequencies.We also find the quasinormal modes of the black hole,which tell us that the EPM spacetime is very stable.

Holographic Superconductor Models with RF^(2) Corrections

We investigate the effect of the RF^(2) correction on the holographic superconductor model in the background of AdS black hole,where R is the Ricci scalar of spacetime and F^(2)=FμνFμνis the Maxwell field strength.We observe that,similar to the effect caused by the Weyl correction,the higher RF^(2) correction term can make it easier for the scalar operator to condense and result in the larger deviation from the expected relation in the gap frequency.However,we find that the condensation gap becomes larger as the RF^(2) correction term increases,which is in strong contrast to the influences of the Weyl correction and Gauss–Bonnet correction.

Statistical Entropy of the Kaluza-Klein Black Hole from the Horizon Conformal Field Theory

The statistical entropy of the Kaluza-Klein black hole is studied by counting the black hole states which form an algebra of diffeomorphism at Killing horizon with a central charge.It is shown that the entropy yielded by the standard Cardy formula agrees with the Bekenstein-Hawking entropy only if we take period T of function u as the periodicity of the Euclidean black hole.On the other hand,the first-order quantum correction to the entropy is proportional to logarithm of the Bekenstein-Hawking entropy with a factor-1/2.

Entropy of the Nonminimally Coupled Quantum Scalar Fields in a Stationary Axisymmetric Einstein-Maxwell Dilaton- Axion Black Hole

The statistical-mechanical entropy of the stationary axisymmetric Einstein-Maxwell dilaton-axion black hole is investigated by using the “brick wall” model in which the original Dirichlet condition is replaced by a scattering ansatz for the field functions at the event horizon and regularized with the Pauli-Villars scheme. It is also shown, for the Kerr black hole, that the statistical-mechanical entropy obtained from our derivation coincides with the one-loop correction to its thermodynamical entropy obtained by the conical singularity method.

Thermodynamical and Statistical-Mechanical Entropies of the General Static Spherically Symmetric Black Hole

The thermodynamical entropy of the general four-dimensional static spherically symmetric black hole is obtained by using the Euclidean path integral approach of Gibbons-Hawking,and its statistical-mechanical entropy is calculated according to the brick wall model of’t Hooft.It is shown that the two entropies are not identical in general and the difference between them depends on the area of the horizon and the Ricci scalar curvature on the event horizon.

Quantum Corrections to the Entropy of the Black Hole with a Global Monopole or a Cosmic String

The quantum corrections to the entropy of the static black holes with a global monopole or a cosmic string are studied by two methods:the brick wall and the Euclidean path integral.If we ignore the usual contribution from the vacuum surrounding the system,then the two approaches give the same results.The quantum corrections for the static black holes consist of two parts:One is quadratically divergent term which takes the geometric character.The other is a logarithmically divergent term which is not proportional to the horizon area.The renormalization of the quadratically and logarithmically divergent is also investigated.

Thermodynamics of a Static Dilaton Black Hole

The thermodynamics of a static dilaton black hole is investigated by Euclidean path integral.Four interesting results are obtained:(Ⅰ)Although the temperature,heat capacity and chemical potential have different forms as compared to general classical static charged black hole,the Bardeen-Carter-Hawking thermodynamical laws are valid for the black hole.(Ⅱ)The entropy and area of the event horizon are zero but the energy,temperature and surface gravity are non-zero for extremal case(rh=2M=b).(Ⅲ)The charged black hole does not possess second order phase transitions as the Reissner-Nordstrom black hole since its heat capacity is negative.(Ⅳ)The action is equal to the entropy,and both quantities coincide with one quarter of area of the event horizon.