459 research outputs found
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 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 gravity as an extra scalar field, has a
tiny mass of the order of magnitude , 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
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