Three-dimensional$$(\psi \overline \psi )^2 $$ model with an external non-abelian field, temperature and a chemical potentialmodel with an external non-abelian field, temperature and a chemical potential

Abstract

The phase structure of the four-fermion model (1) under the action of an external chromomagnetic fieldH, temperatureT and a chemical potential Μ has been studied in three dimensions. It has been shown that: 1) the conditionsH ⊋ 0,T, Μ = 0 lead unavoidably to a spontaneous breakdown of the chiral invariance; 2) the chiral symmetry can be restored at sufficiently largeT or Μ values. The expressions for the critical temperature and quark mass in the range of large and small external field values have been derived.