Noncommutative cosmological models coupled to a perfect fluid and a cosmological constant

In this work we carry out a noncommutative analysis of several Friedmann-Robert-Walker models, coupled to different types of perfect fluids and in the presence of a cosmological constant. The classical field equations are modified, by the introduction of a shift operator, in order to introduce noncommutativity in these models. We notice that the noncommutative versions of these models show several relevant differences with respect to the correspondent commutative ones.Comment: 27 pages. 7 figures. JHEP style.arXiv admin note: substantial text overlap with arXiv:1104.481

A GENERAL-SOLUTION OF THE BV-MASTER EQUATION AND BRST FIELD-THEORIES

For a class of first order gauge theories it was shown that the proper solution of the BV-master equation can be obtained straightforwardly. Here we present the general condition which the gauge generators should satisfy to conclude that this construction is relevant. The general procedure is illustrated by its application to the Chern-Simons theory in any odd dimension. Moreover, it is shown that this formalism is also applicable to BRST field theories when one replaces the role of the exterior derivative with the BRST charge of first quantization

BFV-BRST ANALYSIS OF THE CLASSICAL AND QUANTUM Q-DEFORMATIONS OF THE SL(2) ALGEBRA

BFV-BRST charge for quantum algebras is not unique. Different constructions of it in classical and quantum phase space for the universal enveloping algebra of the q-deformed sl(2) are discussed. In the quantum framework a positive definite scalar product is used to introduce a co-BFV-BRST charge to study the cohomology problem by means of the techniques of the non-deformed case. Moreover, deformation of the phase space without deforming the generators of sl(2) is considered. HBAR-q-deformation of the phase space is shown to yield the Witten's second deformation for sl(2). To study the BFV-BRST cohomology problem when both the quantum phase space and the group are deformed, a two-parameter deformation of sl(2) is proposed, and its BFV-BRST charge is given

QUANTIZATION OF DYNAMIC-SYSTEMS WITH REDUCIBLE CONSTRAINTS AND THE SUPERPARTICLE

Batalin-Fradkin-Vilkovisky-Becchi-Rouet-Stora-Tyutin quantization of dynamical systems, with irreducible first- and reducible second-class constraints satisfying some conditions, is performed by converting the second-class constraints into effective first-class ones. But restricting the phase space in an unusual way is necessary. A path integral is proposed by imposing some new second-class constraints to keep the original ones converted into effective first-class constraints. The new second-class constraints are reducible and the reducibility conditions include the new reducible first-class ones. The general definition of reducibility and the method of quantization are presented. In the light of these, a new set of covariant constraints for the massless Casalbuoni-Brink-Schwarz superparticle in 10 dimensions is proposed. Although the first- and second-class constraints of the new set are separated, they are infinitely reducible. Quantization of this dynamical system in a unitary gauge is given

A GENERAL-SOLUTION OF THE MASTER EQUATION FOR A CLASS OF 1ST-ORDER SYSTEMS

Inspired by the formulation of the Batalin-Vilkovisky method of quantization in terms of ''odd time,'' we show that for a class of gauge theories which are first order in the derivatives, the kinetic term is bilinear in the fields, and the interaction part satisfies some properties, it is possible to give the solution of the master equation in a very simple way. To clarify the general procedure we discuss its application to Yang-Mills theory, massive (Abelian) theory in the Stueckelberg formalism, relativistic particle and to the self-interacting antisymmetric tensor field