ON PLANAR FERMIONS WITH QUARTIC INTERACTION AT FINITE TEMPERATURE AND DENSITY

D.C. CABRA; G. L. ROSSINI

EUROPEAN PHYSICAL JOURNAL B - CONDENSED MATTER

European Physical Society

Lugar: Paris; Año: 2002 vol. 29 p. 529 - 532

1434-6028

We study the breaking of parity symmetry in the 2+1 Gross-Neveumodel at finite temperature with chemical potential $mu$, in thepresence of an external magnetic field. We find that therequirement of gauge invariance, which is considered mandatory inthe presence of gauge fields, breaks parity at any finitetemperature and provides for dynamical mass generation, preventingsymmetry restoration for any non-vanishing $mu$. The dynamicalmass becomes negligibly small as temperature is raised. We commenton the relevance of our observation for the gap generation ofnodal quasi-particles in the pseudo-gap phase of high $T_c$superconductors.