71 research outputs found
Monopole Vacuum in Non-Abelian Theories
It is shown that, in the theory of interacting Yang -Mills fields and a Higgs
field, there is a topological degeneracy of Bogomol'nyi-Prasad-Sommerfield
(BPS) monopoles and that there arises, in this case, a chromoelectric monopole
characterized by a new topological variable that describes transitions between
topological states of the monopole in the Minkowski space (in just the same way
as an instanton describes such transitions in the Euclidean space). The limit
of an infinitely large mass of the Higgs field at a finite density of the BPS
monopole is considered as a model of the stable vacuum in the pure Yang-Mills
theory. It is shown that, in QCD, such a monopole vacuum may lead to a rising
potential, a topological confinement and an additional mass of the
meson. The relationship between the result obtained here for the generating
functional of perturbation theory and Faddeev-Popov integral is discussed
Bogolyubov Quasiparticles in Constrained Systems
The paper is devoted to the formulation of quantum field theory for an early
universe in General Relativity considered as the Dirac general constrained
system. The main idea is the Hamiltonian reduction of the constrained system in
terms of measurable quantities of the observational cosmology: the world proper
time, cosmic scale factor, and the density of matter. We define " particles" as
field variables in the holomorphic representation which diagonalize the
measurable density. The Bogoliubov quasiparticles are determined by
diagonalization of the equations of motion (but not only of the initial
Hamiltonian) to get the set of integrals of motion (or conserved quantum
numbers, in quantum theory). This approach is applied to describe particle
creation in the models of the early universe where the Hubble parameter goes to
infinity.Comment: 13 pages, Late
Von Neumann's Quantization of General Relativity
Von Neumann's procedure is applied for quantization of General Relativity. We
quantize the initial data of dynamical variables at the Planck epoch, where the
Hubble parameter coincides with the Planck mass. These initial data are defined
via the Fock simplex in the tangent Minkowskian space-time and the Dirac
conformal interval. The Einstein cosmological principle is applied for the
average of the spatial metric determinant logarithm over the spatial volume of
the visible Universe. We derive the splitting of the general coordinate
transformations into the diffeomorphisms (as the object of the second N\"other
theorem) and the initial data transformations (as objects of the first N\"other
theorem). Following von Neumann, we suppose that the vacuum state is a quantum
ensemble. The vacuum state is degenerated with respect to quantum numbers of
non-vacuum states with the distribution function that yields the Casimir effect
in gravidynamics in analogy to the one in electrodynamics. The generation
functional of the perturbation theory in gravidynamics is given as a solution
of the quantum energy constraint. We discuss the region of applicability of
gravidynamics and its possible predictions for explanation of the modern
observational and experimental data.Comment: 14 pages, updated version with extended discussio
Heavy--light mesons in a bilocal effective theory
Heavy--light mesons are described in an effective quark theory with a
two--body vector--type interaction. The bilocal interaction is taken to be
instantaneous in the rest frame of the bound state, but formulated covariantly
through the use of a boost vector. The chiral symmetry of the light flavor is
broken spontaneously at mean field level. The framework for our discussion of
bound states is the effective bilocal meson action obtained by bosonization of
the quark theory. Mesons are described by 3--dimensional wave functions
satisfying Salpeter equations, which exhibit both Goldstone solutions in the
chiral limit and heavy--quark symmetry for . We present
numerical solutions for pseudoscalar -- and --mesons. Heavy--light meson
spectra and decay constants are seen to be sensitive to the description of
chiral symmetry breaking (dynamically generated vs.\ constant quark mass).Comment: (34 p., standard LaTeX, 7 PostScript figures appended)
UNITUE-THEP-17/9
Pion Polarizability in the NJL model and Possibilities of its Experimental Studies in Coulomb Nuclear Scattering
The charge pion polarizability is calculated in the Nambu-Jona-Lasinio model,
where the quark loops (in the mean field approximation) and the meson loops (in
the approximation) are taken into account. We show that quark loop
contribution dominates, because the meson loops strongly conceal each other.
The sigma-pole contribution plays the main role and
contains strong t-dependence of the effective pion polarizability at the region
. Possibilities of experimental test of this sigma-pole
effect in the reaction of Coulomb Nuclear Scattering are estimated for the
COMPASS experiment.Comment: 11 pages, 8 figure
Inertial mechanism: dynamical mass as a source of particle creation
A kinetic theory of vacuum particle creation under the action of an inertial
mechanism is constructed within a nonpertrubative dynamical approach. At the
semi-phenomenological level, the inertial mechanism corresponds to quantum
field theory with a time-dependent mass. At the microscopic level, such a
dependence may be caused by different reasons: The non-stationary Higgs
mechanism, the influence of a mean field or condensate, the presence of the
conformal multiplier in the scalar-tensor gravitation theory etc. In what
follows, a kinetic theory in the collisionless approximation is developed for
scalar, spinor and massive vector fields in the framework of the oscillator
representation, which is an effective tool for transition to the quasiparticle
description and for derivation of non-Markovian kinetic equations. Properties
of these equations and relevant observables (particle number and energy
densities, pressure) are studied. The developed theory is applied here to
describe the vacuum matter creation in conformal cosmological models and
discuss the problem of the observed number density of photons in the cosmic
microwave background radiation. As other example, the self-consistent evolution
of scalar fields with non-monotonic self-interaction potentials (the
W-potential and Witten - Di Vecchia - Veneziano model) is considered. In
particular, conditions for appearance of tachyonic modes and a problem of the
relevant definition of a vacuum state are considered.Comment: 51 pages, 18 figures, submitted to PEPAN (JINR, Dubna); v2: added
reference
Self - Consistent Description of e+e-gamma Plasma Created from the Vacuum in a Strong Electric Laser Field
In the present work a closed system of kinetic equations is obtained for the
description of the vacuum creation of an electron - positron plasma and
secondary photons due to a strong laser field. An estimate for the photon
energy distribution is obtained. In the Markovian approximation the photon
distribution has a 1/k spectrum (flicker noise).Comment: 6 pages, contribution to Proceedings of the International Bogolyubov
Conference, Dubna (Russia), August 21-27, 200
BBGKY kinetic approach for an e-e+gamma plasma created from the vacuum in a strong laser-generated electric field: The one-photon annihilation channel
In the present work a closed system of kinetic equations is obtained from the
truncation of the BBGKY hierarchy for the description of the vacuum creation of
an electron - positron plasma and secondary photons due to a strong laser
field. This truncation is performed in the Markovian approximation for the
one-photon annihilation channel which is accessible due to the presence of the
strong external field. Estimates of the photon production rate are obtained for
different domains of laser field parameters (frequency nu and field strength
E). A huge quantity of optical photons of the quasiclassical laser field is
necessary to satisfy the conservation laws of energy and momentum of the
constituents (e-, e+, gamma) in this channel. Since the number of these optical
photons corresponds to the order of perturbation theory, a vanishingly small
photon production rate results for the optical region and strongly subcritical
fields E << E_c. In the gamma-ray region nu <~ m the required number of laser
photons is small and the production rate of photons from the one-photon
annihilation process becomes accessible to observations for subcritical fields
E <~ E_c. In the infrared region the photon distribution has a 1/k spectrum
typical for flicker noise.Comment: 14 pages, 1 figure, one reference with referring text added and one
citation correcte
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