Thermodynamics of Black Hole in (N+3)-dimensions from Euclidean N-brane Theory

In this article we consider an N-brane description of an (N+3)-dimensional black hole horizon. First of all, we start by reviewing a previous work where a string theory is used as describing the dynamics of the event horizon of a four dimensional black hole. Then we consider a particle model defined on one dimensional Euclidean line in a three dimensional black hole as a target spacetime metric. By solving the field equations we find a ``world line instanton'' which connects the past event horizon with the future one. This solution gives us the exact value of the Hawking temperature and to leading order the Bekenstein-Hawking formula of black hole entropy. We also show that this formalism is extensible to an arbitrary spacetime dimension. Finally we make a comment of one-loop quantum correction to the black hole entropy

Localization of Gravitino on a Brane

We show how the spin 3/2 gravitino field can be localized on a brane in a general framework of supergravity theory. Provided that a scalar field coupled to the Rarita-Schwinger field develops an vacuum expectation value (VEV) whose phase depends on the 'radial' coordinate in extra internal space, the gravitino is localized on a brane with the exponentially decreasing warp factor by selecting an appropriate value of the VEV.Comment: 7 pages, LaTex 2e, no figure

Cosmic Acceleration in the Nonlocal Approach to the Cosmological Constant Problem

We have recently constructed a manifestly local formulation of a nonlocal approach to the cosmological constant problem which can treat with quantum effects from both matter and gravitational fields. In this formulation, it has been explicitly shown that the effective cosmological constant is radiatively stable even in the presence of the gravitational loop effects. Since we are naturally led to add the $R^2$ term and the corresponding topological action to an original action, we make use of this formulation to account for the late-time acceleration of expansion of the universe in case of the open universes with infinite space-time volume. We will see that when the "scalaron", which exists in the $R^2$ gravity as an extra scalar field, has a tiny mass of the order of magnitude ${\cal{O}}(1 meV)$, we can explain the current value of the cosmological constant in a consistent manner.Comment: 17 pages. arXiv admin note: text overlap with arXiv:1709.0818