Quantum fields in toroidal topology

The standard representation of c*-algebra is used to describe fields in compactified space-time dimensions characterized by topologies of the type Gamma(d)(D) = (S-1)(d) x MD-d The modular operator is generalized to introduce representations of isometry groups. The Poincare symmetry is analyzed and then we construct the modular representation by using linear transformations in the field modes, similar to the Bogoliubov transformation. This provides a mechanism for compactification of the Minkowski space-time, which follows as a generalization of the Fourier integral representation of the propagator at finite temperature. An important result is that the 2 x 2 representation of the real-time formalism is not needed. The end result on calculating observables is described as a condensate in the ground state. We initially analyze the free Klein-Gordon and Dirac fields, and then formulate non-abelian gauge theories in Gamma(d)(D). Using the S-matrix, the decay of particles is calculated in order to show the effect of the compactification. (C) 2011 Elsevier Inc. All rights reserved.