2,292 research outputs found
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
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
Electrostatic in Reissner-Nordstrom space-time with a conical defect
We calculate the electrostatic potential generated by a point charge in the
space-time of Reissner-Nordstrom with a conical defect. An expression for the
self-energy is also presented.Comment: 7 pages, LATEX fil
Taxa fotossintĂ©tica, produção e teor de sĂłlidos solĂșveis totais de frutos de meloeiro afetados por amarelĂŁo e por mosca-branca.
bitstream/CNPAT-2010/11913/1/bd-20.pd
Efeito da resinose na fotossĂntese do cajueiro-anĂŁo precoce.
A resinose Ă© uma das principais doenças do cajueiro em algumas regiĂ”es do semi-ĂĄrido nordestino, provocando danos relacionados Ă redução na produção da planta e do pomar. Como inexistem estudos visando quantificar danos Ă produção ou a Ă elucidação dos efeitos da doença na fisiologia da planta, o presente trabalho objetivou determinar os efeitos da resinose sobre alguns parĂąmetros fisiolĂłgicos, especialmente sobre a fotossĂtese de plantas de cajueiro-anĂŁo precoce.bitstream/CNPAT-2010/9021/1/Bd-008.pd
Nonrelativistic Quantum Analysis of the Charged Particle-Dyon System on a Conical Spacetime
In this paper we develop the nonrelativistic quantum analysis of the charged
particle-dyon system in the spacetime produced by an idealized cosmic string.
In order to do that, we assume that the dyon is superposed to the cosmic
string. Considering this peculiar configuration {\it conical} monopole
harmonics are constructed, which are a generalizations of previous monopole
harmonics obtained by Wu and Yang(1976 {\it Nucl. Phys. B} {\bf 107} 365)
defined on a conical three-geometry. Bound and scattering wave functions are
explicitly derived. As to bound states, we present the energy spectrum of the
system, and analyze how the presence of the topological defect modifies
obtained result. We also analyze this system admitting the presence of an extra
isotropic harmonic potential acting on the particle. We show that the presence
of this potential produces significant changes in the energy spectrum of the
system.Comment: Paper accepted for publication in Classical and Quantum Gravit
Relativistic Quantum Scattering on a Cone
We study the relativistic quantum mechanical scattering of a bosonic particle
by an infinite straight cosmic string, considering the non-minimal coupling
between the bosonic field and the scalar curvature. In this case, an effective
two-dimensional delta-function interaction takes place besides the usual
topological scattering and a renormalization procedure is necessary in order to
treat the problem that appears in connection with the delta-function.Comment: 22 pages, LATEX fil
Vacuum Polarization by a Magnetic Flux Tube at Finite Temperature in the Cosmic String Spacetime
In this paper we analyse the effect produced by the temperature in the vacuum
polarization associated with charged massless scalar field in the presence of
magnetic flux tube in the cosmic string spacetime. Three different
configurations of magnetic fields are taken into account: a homogeneous
field inside the tube, a field proportional to and a
cylindrical shell with -function. In these three cases, the axis of the
infinitely long tube of radius coincides with the cosmic string. Because
the complexity of this analysis in the region inside the tube, we consider the
thermal effect in the region outside. In order to develop this analysis, we
construct the thermal Green function associated with this system for the three
above mentioned situations considering points in the region outside the tube.
We explicitly calculate in the high-temperature limit, the thermal average of
the field square and the energy-momentum tensor.Comment: 16 pages, 1 figur
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