DYNAMICAL SYMMETRY-BREAKING IN THE NAMBU-JONA-LASINIO MODEL WITH EXTERNAL GRAVITATIONAL AND CONSTANT ELECTRIC-FIELDS

An investigation of the Nambu-Jona-Lasinio model with external constan t electric and weak gravitational fields is carried out in three-and f our-dimensional spacetimes. The effective potential of the composite b i-fermionic fields is calculated keeping terms linear in the curvature , while the electric field effect is treated exactly by means of the p roper-time formalism. A rich dynamical symmetry breaking pattern. acco mpanied by phase transitions which are ruled, independently, by both t he curvature and the electric field strength is found. Numerical simul ations of the transitions are presented.