New approach to microscopic theory of normal Fermi systems

A new version of the normal Fermi system microscopic theory is suggested. A functional equation for the effective potential R of the quasiparticle interaction is obtained. Methods for the evaluation of R in terms of the particle interaction potential are discussed. It is shown that in the well-known local approximation, the functional equation for R is reduced to an integro-differential one. For a number of model examples for which the Monte Carlo equation of state is known, the local approximation proves to reproduce the Monte Carlo results to an accuracy of a few percent. The method developed is applied to superfluid Fermi systems. The equation for the evaluation of the gap in the single-particle excitation spectrum in terms of the interaction potential R is obtained. (orig.)