INITIAL-CONDITION PROBLEM FOR A CHIRAL GROSS-NEVEU SYSTEM

A time-dependent projection technique is used to treat the initial-val ue problem for self-interacting fermionic fields. On the basis of the general dynamics of the fields, we derive formal equations of kinetic- type for the set of one-body dynamical variables. A nonperturbative me an-held expansion can be written for these equations. We treat this ex pansion in lowest order, which corresponds to the Gaussian mean-field approximation, for a uniform system described by the chiral Gross-Neve u Hamiltonian. Standard stationary features of the model, such as dyna mical mass generation due to chiral symmetry breaking and a phenomenon analogous to dimensional transmutation, are reobtained in this contex t. The mean-field time evolution of nonequilibrium initial states is d iscussed.