631 research outputs found
Vacuum Polarization at Finite Temperature around a Magnetic Flux Cosmic String
We consider a general situation where a charged massive scalar field
at finite temperature interacts with a magnetic flux cosmic string.
We determine a general expression for the Euclidean thermal Green's function of
the massive scalar field and a handy expression for a massless scalar field.
With this result, we evaluate the thermal average and the
thermal average of the energy-momentum tensor of a nonconformal massless scalar
field.Comment: 22 pages, latex, no figure
Electrostatics in a simple wormhole revisited
The electrostatic potential generated by a point charge at rest in a simple
static, spherically symmetric wormhole is given in the form of series of
multipoles and in closed form. The general potential which is physically
acceptable depends on a parameter due to the fact that the monopole solution is
arbitrary. When the wormhole has Z2-symmetry, the potential is completely
determined. The calculation of the electrostatic self-energy and of the
self-force is performed in all cases considered.Comment: 16 pages, no figure
Quantum phase shift and neutrino oscillations in a stationary, weak gravitational field
A new method based on Synge's world function is developed for determining
within the WKB approximation the gravitationally induced quantum phase shift of
a particle propagating in a stationary spacetime. This method avoids any
calculation of geodesics. A detailed treatment is given for relativistic
particles within the weak field, linear approximation of any metric theory. The
method is applied to the calculation of the oscillation terms governing the
interference of neutrinos considered as a superposition of two eigenstates
having different masses. It is shown that the neutrino oscillations are not
sensitive to the gravitomagnetic components of the metric as long as the spin
contributions can be ignored. Explicit calculations are performed when the
source of the field is a spherical, homogeneous body. A comparison is made with
previous results obtained in Schwarzschild spacetime.Comment: 14 pages, no figure. Enlarged version; added references. In the
Schwarzschild case, our results on the non-radial propagation are compared
with the previous work
Self-Dual Chern-Simons Solitons in (2+1)-Dimensional Einstein Gravity
We consider here a generalization of the Abelian Higgs model in curved space,
by adding a Chern--Simons term. The static equations are self-dual provided we
choose a suitable potential. The solutions give a self-dual
Maxwell--Chern--Simons soliton that possesses a mass and a spin
Bogomolnyi Bound with a Cosmological Constant
Bogomolnyi-type bound is constructed for the topological solitons in O(3)
nonlinear model coupled to gravity with a negative cosmological
constant. Spacetimes made by self-dual solutions form a class of G\"{o}del-type
universe. In the limit of a spinless massive point particle, the obtained
stationary metric does not violate the causality and it is a new point particle
solution different from the known static hyperboloid and black hole. We also
showed that static Nielsen-Olesen vortices saturate Bogomolnyi-type bound only
when the cosmological constant vanishes.Comment: 11 pages, RevTe
Self-Forces on Electric and Magnetic Linear Sources in the Space-Time of a Cosmic String
In this paper we calculate the magnetic and electric self-forces, induced by
the conical structure of a cosmic string space-time, on a long straight wire
which presents either a constant current or a linear charge density. We also
show how these self-forces are related by a Lorentz tranformation and, in this
way, explain what two different inertial observers detect in their respective
frames.Comment: 10 pages, LaTeX, to be published in Phys. Rev. D
Leukemia-related chromosomal loss detected in hematopoietic progenitor cells of benzene-exposed workers.
Benzene exposure causes acute myeloid leukemia and hematotoxicity, shown as suppression of mature blood and myeloid progenitor cell numbers. As the leukemia-related aneuploidies monosomy 7 and trisomy 8 previously had been detected in the mature peripheral blood cells of exposed workers, we hypothesized that benzene could cause leukemia through the induction of these aneuploidies in hematopoietic stem and progenitor cells. We measured loss and gain of chromosomes 7 and 8 by fluorescence in situ hybridization in interphase colony-forming unit-granulocyte-macrophage (CFU-GM) cells cultured from otherwise healthy benzene-exposed (n=28) and unexposed (n=14) workers. CFU-GM monosomy 7 and 8 levels (but not trisomy) were significantly increased in subjects exposed to benzene overall, compared with levels in the control subjects (P=0.0055 and P=0.0034, respectively). Levels of monosomy 7 and 8 were significantly increased in subjects exposed to <10 p.p.m. (20%, P=0.0419 and 28%, P=0.0056, respectively) and ≥ 10 p.p.m. (48%, P=0.0045 and 32%, 0.0354) benzene, compared with controls, and significant exposure-response trends were detected (P(trend)=0.0033 and 0.0057). These data show that monosomies 7 and 8 are produced in a dose-dependent manner in the blood progenitor cells of workers exposed to benzene, and may be mechanistically relevant biomarkers of early effect for benzene and other leukemogens
Developed Adomian method for quadratic Kaluza-Klein relativity
We develop and modify the Adomian decomposition method (ADecM) to work for a
new type of nonlinear matrix differential equations (MDE's) which arise in
general relativity (GR) and possibly in other applications. The approach
consists in modifying both the ADecM linear operator with highest order
derivative and ADecM polynomials. We specialize in the case of a 44
nonlinear MDE along with a scalar one describing stationary cylindrically
symmetric metrics in quadratic 5-dimensional GR, derive some of their
properties using ADecM and construct the \textit{most general unique power
series solutions}. However, because of the constraint imposed on the MDE by the
scalar one, the series solutions terminate in closed forms exhausting all
possible solutions.Comment: 17 pages (minor changes in reference [30]
Vortices in Bogomol'nyi Limit of Einstein Maxwell Higgs Theory with or without External Sources
The Abelian Higgs model with or without external particles is considered in
curved space. Using the dual transformation, we rewrite the model in terms of
dual gauge fields and derive the Bogomol'nyi-type bound. We examine
cylindrically symmetric solutions to Einstein equations and the first-order
Bogomol'nyi equations, and find vortex solutions and vortex-particle composites
which lie on the spatial manifold with global geometry described by a cylinder
asymptotically or a two sphere in addition to the well-known cone.Comment: LaTeX, 23 pages, 10 LaTeX figures included, KHTP-93-05, SNUTP-93-100,
DPNU-93-46. (A note and several references added
Note on the point-splitting procedure to evaluate vacuum fluctuation in certain cylindrically symmetric backgrounds
We revisit two-point function approaches used to study vacuum fluctuation in
wedge-shaped regions and conical backgrounds. Appearance of divergent integrals
is discussed and circumvented. The issue is considered in the context of a
massless scalar field in cosmic string spacetime.Comment: REVTeX file, 7 page
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