3 research outputs found
Casimir effect in de Sitter and Anti-de Sitter braneworlds
We discuss the bulk Casimir effect (effective potential) for a conformal or
massive scalar when the bulk represents five-dimensional AdS or dS space with
two or one four-dimensional dS brane, which may correspond to our universe.
Using zeta-regularization, the interesting conclusion is reached, that for both
bulks in the one-brane limit the effective potential corresponding to the
massive or to the conformal scalar is zero. The radion potential in the
presence of quantum corrections is found. It is demonstrated that both the dS
and the AdS braneworlds may be stabilized by using the Casimir force only. A
brief study indicates that bulk quantum effects are relevant for brane
cosmology, because they do deform the de Sitter brane. They may also provide a
natural mechanism yielding a decrease of the four-dimensional cosmological
constant on the physical brane of the two-brane configuration.Comment: 37 pages, LaTeX, references added, some revision is done, version to
appear in PR
Cosmological and black hole brane-world Universes in higher derivative gravity
General model of multidimensional -gravity including Riemann tensor
square term (non-zero case) is considered. The number of brane-worlds in
such model is constructed (mainly in five dimensions) and their properties are
discussed. Thermodynamics of S-AdS BH (with boundary) is presented when
perturbation on is used. The entropy, free energy and energy are
calculated. For non-zero the entropy (energy) is not proportional to the
area (mass). The equation of motion of brane in BH background is presented as
FRW equation. Using dual CFT description it is shown that dual field theory is
not conformal one when is not zero. In this case the holographic entropy
does not coincide with BH entropy (they coincide for Einstein gravity or
HD gravity where AdS/CFT description is well applied).
Asymmetrically warped background (analog of charged AdS BH) where Lorentz
invariance violation occurs is found. The cosmological 4d dS brane connecting
two dS bulk spaces is formulated in terms of parameters of -gravity.
Within proposed dS/CFT correspondence the holographic conformal anomaly from
five-dimensional higher derivative gravity in de Sitter background is
evaluated.Comment: LaTeX file 40 pages, references added, version to appear in PR
Nucleation of Brane Universes
The creation of brane universes induced by a totally antisymmetric tensor
living in a fixed background spacetime is presented, where a term involving the
intrinsic curvature of the brane is considered. A canonical quantum mechanical
approach employing Wheeler-DeWitt equation is done. The probability nucleation
for the brane is calculated taking into account both an instanton method and a
WKB approximation. Some cosmological implications arose from the model are
presented.Comment: 19 pages, 2 figure