60 research outputs found
Vacuum polarization by fermionic fields in higher dimensional cosmic string space-time
In this paper we investigate vacuum polarization effects associated with
charged massive quantum fermionic fields in a six-dimensional cosmic string
space-times considering the presence of a magnetic flux running along its core.
We have shown that for specific values of the parameters which codify the
presence of the cosmic string, and the fractional part of the ratio of the
magnetic flux by the quantum one, a closed expression for the respective Green
function is obtained. Adopting this result, we explicitly calculate the
renormalized vacuum expectation value of the energy-momentum tensors,
, and analyse this result in some limitting cases.Comment: Talk presented in the 7th Alexander Friedmann International Seminar
on Gravitation and Cosmology, held in Joao Pessoa/PB, Brazi
Vacuum polarization in a cosmic string spacetime induced by flat boundary
In this paper we analyze the vacuum expectation values of the field squared
and the energy-momentum tensor associated to a massive scalar field in a higher
dimensional cosmic string spacetime, obeying Dirichlet or Neumann boundary
conditions on the surface orthogonal to the string.Comment: 12 pages, 5 figures, talk presented at the 8th Alexander Friedmann
International Seminar on Gravitation and Cosmology, in Rio de Janeiro, Brazi
Spinor Green function in higher-dimensional cosmic string space-time in the presence of magnetic flux
In this paper we investigate the vacuum polarization effects associated with
quantum fermionic charged fields in a generalized dimensional cosmic
string space-times considering the presence of a magnetic flux along the
string. In order to develop this analysis we calculate a general expression for
the respective Green function, valid for several different values of , which
is expressed in terms of a bispinor associated with the square of the Dirac
operator. Adopting this result, we explicitly calculate the renormalized vacuum
expectation values of the energy-momentum tensors, , associated
with massless fields. Moreover, for specific values of the parameters which
codify the cosmic string and the fractional part of the ratio of the magnetic
flux by the quantum one, we were able to present in closed forms the bispinor
and the respective Green function for massive fields.Comment: 27 pages, 6 figures. This version accepted for publication in JHEP
contains a minor modification and two new reference
Reply to "Comment on 'Gravitating Magnetic Monopole in the Global Monopole Spacetime' "
In this Reply I present some arguments in favor of the stability of the
topological defect composed by global and magnetic monopoles.Comment: 1 page, no figures. Revised version improves the theoretical analysis
about electrostatic self-interaction in the global monopole spacetim
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