1,973 research outputs found
EYM equations in the presence of q-stars
We study Einstein-Yang-Mills equations in the presence of gravitating
non-topological soliton field configurations, of q-ball type. We produce
numerical solutions, stable with respect to gravitational collapse and to
fission into free particles, and we study the effect of the field strength and
the eigen-frequency to the soliton parameters. We also investigate the
formation of such soliton stars when the spacetime is asymptotically anti de
Sitter.Comment: 11 pages, to appear in Phys. Rev.
Q-stars in extra dimensions
We study q-stars with global and local U(1) symmetry in extra dimensions in
asymptotically anti de Sitter or flat spacetime. The behavior of the mass,
radius and particle number of the star is quite different in 3 dimensions, but
in 5, 6, 8 and 11 dimensions is similar to the behavior in 4.Comment: 18 pages, to appear in Phys. Rev.
Vortex solutions of a Maxwell-Chern-Simons field coupled to four-fermion theory
We find the static vortex solutions of the model of Maxwell-Chern-Simons
gauge field coupled to a (2+1)-dimensional four-fermion theory. Especially, we
introduce two matter currents coupled to the gauge field minimally: the
electromagnetic current and a topological current associated with the
electromagnetic current. Unlike other Chern-Simons solitons the N-soliton
solution of this theory has binding energy and the stability of the solutions
is maintained by the charge conservation laws.Comment: 7 pages, harvmac, To be published in Phys. Rev. D5
Bogomol'nyi Equations of Maxwell-Chern-Simons vortices from a generalized Abelian Higgs Model
We consider a generalization of the abelian Higgs model with a Chern-Simons
term by modifying two terms of the usual Lagrangian. We multiply a dielectric
function with the Maxwell kinetic energy term and incorporate nonminimal
interaction by considering generalized covariant derivative. We show that for a
particular choice of the dielectric function this model admits both topological
as well as nontopological charged vortices satisfying Bogomol'nyi bound for
which the magnetic flux, charge and angular momentum are not quantized. However
the energy for the topolgical vortices is quantized and in each sector these
topological vortex solutions are infinitely degenerate. In the nonrelativistic
limit, this model admits static self-dual soliton solutions with nonzero finite
energy configuration. For the whole class of dielectric function for which the
nontopological vortices exists in the relativistic theory, the charge density
satisfies the same Liouville equation in the nonrelativistic limit.Comment: 30 pages(4 figures not included), RevTeX, IP/BBSR/93-6
Gauged Fermionic Q-balls
We present a new model for a non-topological soliton (NTS) that contains
interacting fermions, scalar particles and a gauge field. Using a variational
approach, we estimate the energy of the localized configuration, showing that
it can be the lowest energy state of the system for a wide range of parameters.Comment: 5 pages, 2 figures; revised version to appear in Phys. Rev.
Flux tube dynamics in the dual superconductor
We study plasma oscillations in a flux tube of the dual superconductor model
of 't Hooft and Mandelstam. A magnetic condensate is coupled to an
electromagnetic field by its dual vector potential, and fixed electric charges
set up a flux tube. An electrically charged fluid (a quark plasma) flows in the
tube and screens the fixed charges via plasma oscillations. We investigate both
Type I and Type II superconductors, with plasma frequencies both above and
below the threshold for radiation into the Higgs vacuum. We find strong
radiation of electric flux into the superconductor in all regimes, and argue
that this invalidates the use of the simplest dual superconductor model for
dynamical problems.Comment: 25 pages Revtex with 11 EPS figure
A Godel-Friedman cosmology?
Based on the mathematical similarity between the Friedman open metric and
Godel's metric in the case of nearby distances, we investigate a new scenario
for the Universe's evolution, where the present Friedman universe originates
from a primordial Godel universe by a phase transition during which the
cosmological constant vanishes. Using Hubble's constant and the present matter
density as input, we show that the radius and density of the primordial Godel
universe are close, in order of magnitude, to the present values, and that the
time of expansion coincides with the age of the Universe in the standard
Friedman model. In addition, the conservation of angular momentum provides, in
this context, a possible origin for the rotation of galaxies, leading to a
relation between the masses and spins corroborated by observational data.Comment: Extended version, accepted for publication in Physical Review
Modification of radiation pressure due to cooperative scattering of light
Cooperative spontaneous emission of a single photon from a cloud of N atoms
modifies substantially the radiation pressure exerted by a far-detuned laser
beam exciting the atoms. On one hand, the force induced by photon absorption
depends on the collective decay rate of the excited atomic state. On the other
hand, directional spontaneous emission counteracts the recoil induced by the
absorption. We derive an analytical expression for the radiation pressure in
steady-state. For a smooth extended atomic distribution we show that the
radiation pressure depends on the atom number via cooperative scattering and
that, for certain atom numbers, it can be suppressed or enhanced.Comment: 8 pages, 2 Figure
Weyl group multiple Dirichlet series constructed from quadratic characters
We construct multiple Dirichlet series in several complex variables whose
coefficients involve quadratic residue symbols. The series are shown to have an
analytic continuation and satisfy a certain group of functional equations.
These are the first examples of an infinite collection of unstable Weyl group
multiple Dirichlet series in greater than two variables.Comment: incorporated referee's comment
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