Dynamical symmetry breaking in Nambu-Jona-Lasinio model under the influence of external electromagnetic and gravitational fields

Abstract

Abstract. Dynamical symmetry breaking is investigated for a four-fermion NambuJona-Lasinio model in external electromagnetic and gravitational fields. An effective potential is calculated in the leading order of the large-N expansion using the propertime Schwinger formalism.Phase transitions accompanying a chiral symmetry breaking in the Nambu-JonaLasinio model are studied in detail. A magnetic calalysis phenomenon is shown to exist in curved spacetime but it turns out to lose its universal character because the chiral symmetry is restored above some critical positive value of the spacetime curvature.

Temperature-induced phase transitions in four-fermion models in curved space-time

“…The influence of a classical gravitational field on the dynamical symmetry breaking has been analyzed in [23]- [27], where the existence of curvature induced phase transitions is evidentiated. The relevance of an external electromagnetic field to descriptions of the early universe is considered in a series of papers where the electromagnetic effects are studied in combination with curvature effects [28]- [31].…”