Untitled

Abstract

The problem of the Bose-Einstein condensate preservation under thermofield and standard gauge-invariant perturbations is discussed. In particular, a new result on the stability of Bose-Einstein condensate under thermofield perturbations of a polynomial type is presented. The approach adopted here strongly relies on previous papers, where functional integral methods were employed in order to study the case of bounded thermofield-like perturbations. Additionally, a description of noncritical Bose matter originating from the ideal Bose gas after switching on the standard, two-body gauge-invariant interactions is presented in terms of Gibbsian-like perturbations of the Poissone-Wiener background measure.