4,651 research outputs found
Casimir Densities for a Massive Fermionic Quantum Field in a Global Monopole Background with Spherical Boundary
We investigate the vacuum expectation value of the energy-momentum tensor
associated with a massive fermionic field obeying the MIT bag boundary
condition on a spherical shell in the global monopole spacetime. The asymptotic
behavior of the vacuum densities is investigated near the sphere center and
surface, and at large distances from the sphere. In the limit of strong
gravitational field corresponding to small values of the parameter describing
the solid angle deficit in global monopole geometry, the sphere-induced
expectation values are exponentially suppressed.Comment: 8 pages, 4 figures, 6th Alexander Friedmann International Seminar on
Gravitation and Cosmolog
Vacuum polarization by topological defects in de Sitter spacetime
In this paper we investigate the vacuum polarization effects associated with
a massive quantum scalar field in de Sitter spacetime in the presence of
gravitational topological defects. Specifically we calculate the vacuum
expectation value of the field square, . Because this investigation
has been developed in a pure de Sitter space, here we are mainly interested on
the effects induced by the presence of the defects.Comment: Talk presented at the 1st. Mediterranean Conference on Classical and
Quantum Gravity (MCCQG
- âŠ