7,288 research outputs found
Path-ordered Phase Factors in Scalar Quantum Electrodynamics
Starting from linear equations for the complex scalar field, the two- and
three-point Green's functions are obtained in the infrared approximation. We
show that the infrared singularity factorizes in the vertex function as in
spinorial QED, reproducing in a straightforward way the result of lenghty
perturbative calculations.Comment: 11 pages, LaTe
What's Wrong with Pauli-Villars Regularization in ?
In this letter we argue that there is no ambiguity between the Pauli-Villars
and other methods of regularization in (2+1)-dimensional quantum
electrodynamics with respect to dynamical mass generation, provided we properly
choose the couplings for the regulators.Comment: 07 pages, Latex, no figure
The Causal Phase in
The operator in Fock space which describes the scattering and
particle production processes in an external time-dependent electromagnetic
potential can be constructed from the one-particle S-matrix up to a
physical phase . In this work we determine this phase for in
(2+1) dimensions, by means of causality, and show that no ultraviolet
divergences arise, in contrast to the usual formalism of .Comment: LaTex, 11 pages, no figure
Classical Bianchi type I cosmology in K-essence theory
We use one of the simplest forms of the K-essence theory and we apply it to
the classical anisotropic Bianchi type I cosmological model, with a barotropic
perfect fluid modeling the usual matter content and with cosmological constant.
The classical solutions for any but the stiff fluid and without cosmological
constant are found in closed form, using a time transformation. We also present
the solution whith cosmological constant and some particular values of the
barotropic parameter. We present the possible isotropization of the
cosmological model, using the ratio between the anisotropic parameters and the
volume of the universe and show that this tend to a constant or to zero for
different cases. We include also a qualitative analysis of the analog of the
Friedmann equation.Comment: 15 pages with one figure, accepted in Advances in High Energy Physic
Classical solutions in five dimensional induced matter theory and its relation to an imperfect fluid
We study five dimensional cosmological models with four dimensional
hypersufaces of the Bianchi type I and V. In this way the five dimensional
vacuum field equations , led us to four dimensional matter
equations and the matter is interpreted as a purely
geometrical property of a fifth dimension. Also, we find that the
energy-momentum tensor induced from the fifth dimension has the structure of an
imperfect fluid that has dissipative terms.Comment: 16 pages, latex, no figure
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