1,776 research outputs found
Non-relativistic quantum systems on topological defects space-times
We study the behavior of non-relativistic quantum particles interacting with
different potentials in the space-times generated by a cosmic string and a
global monopole. We find the energy spectra in the presence of these
topological defects and show how they differ from their free space-time values.Comment: 17 pages, LATEX fil
Vacuum Polarization in the Spacetime of a Scalar-Tensor Cosmic String
We study the vacuum polarization effect in the spacetime generated by a
magnetic flux cosmic string in the framework of a scalar-tensor gravity. The
vacuum expectation values of the energy-momentum tensor of a conformally
coupled scalar field are calculated. The dilaton's contribution to the vacuum
polarization effect is shown explicitly.Comment: 11 pages, LATEX file, 2 eps figure
Aspectos da produção de dois híbridos de melão em função de diferentes fontes de nitrogênio.
O objetivo deste trabalho foi de avaliar a produção dos híbridos
Vacuum Polarization of Massless Spinor Field in Global Monopole Spacetime
We calculate the renormalized vacuum average of the energy-momentum tensor of
massless left-handed spinor field in the pointlike global monopole spacetime
using point-separation approach. The general structure of the vacuum average of
the energy-momentum tensor is obtained and expressed in terms of
component, explicit form of which is analyzed in great details
for arbitrary solid angle deficit.Comment: 12 pages, REVTEX, print error was correcte
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
Self-similar magnetoresistance of Fibonacci ultrathin magnetic films
We study numerically the magnetic properties (magnetization and
magnetoresistance) of ultra-thin magnetic films (Fe/Cr) grown following the
Fibonacci sequence. We use a phenomenological model which includes Zeeman,
cubic anisotropy, bilinear and biquadratic exchange energies. Our physical
parameters are based on experimental data recently reported, which contain
biquadratic exchange coupling with magnitude comparable to the bilinear
exchange coupling. When biquadratic exchange coupling is sufficiently large a
striking self-similar pattern emerges.Comment: 5 pages, 5 EPS figures, REVTeX, accepted for publication in Phys.
Rev.
- …