1,390 research outputs found
Surface vacuum energy and stresses for a brane in de Sitter spacetime
Vacuum expectation values of the surface energy-momentum tensor is
investigated for a massless scalar field obeying mixed boundary condition on a
brane in de Sitter bulk. To generate the corresponding vacuum surface densities
we use the conformal relation between de Sitter and Rindler spacetimes.Comment: 8 pages, no figure, an appendix added, version to appear in PL
Laplacian transfer across a rough interface: Numerical resolution in the conformal plane
We use a conformal mapping technique to study the Laplacian transfer across a
rough interface. Natural Dirichlet or Von Neumann boundary condition are simply
read by the conformal map. Mixed boundary condition, albeit being more complex
can be efficiently treated in the conformal plane. We show in particular that
an expansion of the potential on a basis of evanescent waves in the conformal
plane allows to write a well-conditioned 1D linear system. These general
principle are illustrated by numerical results on rough interfaces
Casimir Forces for Robin Scalar Field on Cylindrical Shell in de Sitter Space
The Casimir stress on a cylinderical shell in background of conformally flat
space-time for massless scalar field is investigated. In the general case of
Robin (mixed) boundary condition formulae are derived for the vacuum
expectation values of the energy-momentum tensor and vacuum forces acting on
boundaries. The special case of the dS bulk is considered then different
cosmological constants are assumed for the space inside and outside of the
shell to have general results applicable to the case of cylindrical domain wall
formations in the early universe.Comment: 10 pages, no figur
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