An. Vasilev et Gy. Panasyuk, ON THE POSSIBILITIES OF A PHASE-TRANSITION OF SUPERCONDUCTING TYPE INTHE GROSS-NEVEU MODEL, Theoretical and mathematical physics, 103(2), 1995, pp. 570-572
It is shown that calculation of the anomalous expectation values for t
he massless Gross-Neveu model in the Hartree-Fock approximation indica
tes the presence of an ordinary chiral phase transition if the couplin
g constant has the normal sign (g>0) and of a different transition of
the superconductivity type if g<0.