FEYNMAN PATH-INTEGRAL REPRESENTATION FOR MANY-FERMION INTERACTING SYSTEMS

A many-fermion interacting system is investigated within the scenario of the Feynman path integral representation of quantum mechanics. Shor t-time propagator algorithms and a basis set, closely related to the c oherent states, are used to obtain the many-body analytic propagator. A second-quantized Hamiltonian involving a restricted set of two-body interactions and the whole set of Coulomb interactions are separately considered and shown to lead to an exact and an approximate propagator , respectively. In the latter case, use of a grand canonical ensemble allows the grand partition function and the density operator matrix to be readily obtained. No further approximations are required in the ca lculation of the trace of the evolution operator involved in the evalu ation of statistical expectation values. (C) 1994 John Wiley & Sons, I nc.