The pressure ensemble as a tool for describing the hadron-quark phase transition

Abstract

We apply the technique of Gaussian regularization to the grand canonical pressure partition function to show that under physically meaningful boundary conditions (non-existence of external confining vessels, i.e., no fixed volumes) the energy density and similar intensive quantities have, in a statistical bootstrap model of extended hadrons (Van der Waals type volume corrections), indeed the singularity claimed in previous papers. Earlier results obtained with an entirely different technique (which had been criticized) are recovered and shown to be correct. The technique used here is useful in all cases where the volume is not imposed from the outside, but results from the internal dynamics of the system as is generally the case in high energy physics and astrophysics.