Y. S. Myung

ENTROPY OF THE THREE-DIMENSIONAL SCHWARZSCHILD de SITTER BLACK HOLE

We study the three-dimensional Schwarzschild–de Sitter (SdS3) black hole which corresponds essentially to a conical defect. We compute the mass of the SdS3 black hole from the correct definition of the mass in asymptotically de Sitter space. Then we clarify the relation between the mass, entropy and temperature for this black hole without any ambiguity. We also establish the SdS3/CFT2-correspondence for the entropy by applying the Cardy formula to a CFT with a central charge c = 3l/2G3. Finally we discuss the entropy bounds for the SdS3 black hole.

Logarithmic corrections to three-dimensional black holes and de Sitter spaces

Abstract We calculate logarithmic corrections to the Bekenstein–Hawking entropy for three-dimensional BTZ black hole with J =0 and Kerr–de Sitter (KdS) space with J =0 including the Schwarzschild–de Sitter (SdS) solution due to thermal fluctuations. It is found that there is no distinction between the event horizon of the BTZ black hole and the cosmological horizon of KdS space. We obtain the same correction to the Cardy formula for BTZ, KdS, and SdS cases. We discuss AdS/CFT and dS/ECFT correspondences in connection with logarithmic corrections.

Role of the brane curvature scalar in the brane world cosmology

Abstract We include the brane curvature scalar to study its cosmological implication in the brane world cosmology. This term is usually introduced to obtain the well-defined stress-energy tensor on the boundary of anti-de-Sitter–Schwarzschild space. Here we treat this as the perturbed term for cosmological purpose. We find corrections to the well-known equation of the brane cosmology. It contains new interesting terms which may play the important role in the brane cosmology.

ABSORPTION CROSS-SECTION IN DE SITTER SPACE

We study the wave equation for a minimally coupled massive scalar in three-dimensional de Sitter space. We compute the absorption cross-section to investigate its cosmological horizon in the southern diamond. Although the absorption cross-section is not defined exactly, it can be determined from the fact that the low-energy s(j = 0)-wave absorption cross-section for a massless scalar is given by the area of the cosmological horizon. On the other hand, the low-temperature limit of j ≠ 0-mode absorption cross-section is useful for extracting information surrounding the cosmological horizon. Finally we mention a computation of the absorption cross-section on the CFT-side using the dS/CFT correspondence.

STANDARD COSMOLOGY FROM THE BRANE COSMOLOGY WITH A LOCALIZED MATTER

We discuss the brane cosmology in the 5D anti de Sitter Reissner–Nordstrom (AdSRN5) space–time. A brane with tension σ is defined as the edge of an AdSRN5 space with mass M and charge Q. In this case we get the CFT-radiation term (ρCFT) from M and the charged dust from Q2 in the Friedmann-like equation. However, this equation is not justified because it contains -term with the negative sign. This is unconventional in view of the standard cosmology. In order to resolve this problem, we introduce a localized dust matter which satisfies Pdm = 0. If , the unwanted is cancelled against and thus one recovers a standard Friedmann–Robertson–Walker universe with CFT-radiation and dust matter. For the stiff matter consideration, we can set ρcsti ~ Q2 with the negative sign. Here we introduce a massless scalar which plays the role of a stiff matter with Psca = ρsca to cancel -ρcsti. In this case, however, we find a mixed version of the standard and brane cosmologies.

Dynamic dS/CFT correspondence using the brane cosmology

Abstract We explore the dynamic dS/CFT correspondence using the moving domain wall(brane) approach in the brane cosmology. The bulk spacetimes are given by the Schwarzschild–de Sitter (SdS) black hole and the topological-de Sitter (TdS) solutions. We consider the embeddings of (Euclidean) moving domain walls into the (Euclidean) de Sitter spaces. The TdS solution is better to describe the static dS/CFT correspondence than the SdS black hole, while in the dynamic dS/CFT correspondence the SdS solution provides situation better than that of the TdS solution. However, we do not find a desirable cosmological scenario from the SdS black hole space.

Greybody factor for the BTZ black hole and a 5D black hole

We study the 5D black holes in the type IIB superstring theory compactified on

Logarithmic corrections to the Bekenstein–Hawking entropy for five-dimensional black holes and de Sitter spaces

S^1 \times T^4

Probing the BTZ black hole with test fields

. Far from horizon, we have flat space-time. Near horizon, we have

Relationship between five-dimensional black holes and de Sitter spaces

AdS_3(BTZ black hole) \times S^3 \times T^4