Temparature as Order Parameter of Broken Scale Invariance

Abstract

In algebraic quantum field theory the (inverse) temperature is shown to be a macroscopic \textit{order parameter} to parametrize mutually disjoint thermal \textit{sectors} arising from the \textit{broken scale invariance} under renormalization-group transformations. This is accomplished in a mathematical formalism for the consistent treatment of \textit{explicitly broken symmetries} such as broken scale invariance, on the basis of a clear-cut criterion for the symmetry breakdown in a unified scheme for sectors proposed recently by the author.