PHASE STRUCTURE OF A FOUR- AND EIGHT-FERMION INTERACTION MODEL AT FINITE TEMPERATURE AND CHEMICAL POTENTIAL IN ARBITRARY DIMENSIONS

Abstract

The phase structure of a four- and eight-fermion interaction model is investigated at finite temperature and chemical potential in arbitrary space–time dimensions, 2 ≤ D < 4. The effective potential and the gap equation are calculated in the leading order of the 1/N expansion. If the first order phase transition takes place, the phase boundary dividing the symmetric and the broken phase is modified by the eight-fermion interaction.