Effective QFT and what it tells us about dynamical torsion

The covariantly constant spacetime torsion is one of the fields which may break Lorentz and CPT symmetry. We review the previous works on the dynamical torsion in the framework of effective quantum field theory (QFT). It turns out that the existence of propagating torsion is strongly restricted by the QFT principles. In particular, the torsion mass must be much greater than the masses of all fermionic particles. In this situation, the main chance to observe torsion is due to some symmetry breaking which may, in principle, produce almost constant background torsion field.Comment: 5 pages, Accepted for publication in the Proceedings of the Fifth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, U.S.A., June 28-July 2, 201

Renormalization in QED and QFT with a Lorentz- and CPT-violating backgrounds

The general features of renormalization and the renormalization group in QED and in general quantum field theories in curved spacetime with additional Lorentz- and CPT-violating background fields are reviewed.Comment: 4 pages, WS styles, Presented at the Sixth Meeting on CPT and Lorentz Symmetry,Bloomington, Indiana, June 17-21, 201

Effective field theory and fundamental interactions

There are many possible gravitational applications of an effective approach to Quantum Field Theory (QFT) in curved space. We present a brief review of effective approach and discuss its impact for such relevant issues as the cosmological constant (CC) problem and inflation driven by vacuum quantum effects. Furthermore it is shown how one can impose significant theoretical constraints on a non-metric gravity using only theoretical effective field theory framework.Comment: LaTeX, 11 pages, 2 figures. Based o talks given at the following meetings: 1. CONFERENCE ON Fundamental Symmetries and Fundamental Constants, ICTP, Trieste, Italy. September 15-18, 2004; 2. Colloquium "Theory and Experiment in Cosmology and Gravitation", in honor of Prof. Jose Plinio Baptista on the occasion of his 70th birthday. (UFES, Vitoria, Brazil. September 22-24, 2004). To be published in the proceeding

Twisted de Rham cohomology, homological definition of the integral and "Physics over a ring"

We define the twisted de Rham cohomology and show how to use it to define the notion of an integral of the form $\int g(x) e^{f(x)}dx$ over an arbitrary ring. We discuss also a definition of a family of integrals and some properties of the homological definition of integral. We show how to use the twisted de Rham cohomology in order to define the Frobenius map on the p-adic cohomology. Finally, we consider two-dimensional topological quantum field theories with general coefficients.Comment: 15 page