Elementary approach to pion condensation

Abstract

In this talk we will present an elementary treatment of a field theoretic many-body system of interacting fermions and bosons. Our approach follows closely the conventional Hartree-Fock and time-dependent Hartree-Fock theories. We have mainly in mind the description of pion condensation, although the techniques employed here have a wider applicability, since their origin may be traced to other branches of physics. A good example of an application of the time-dependent Hartree-Fock method, or RPA to a field-theoretic Hamiltonian is the well-known Bardeen-Pines theory of the electron-phonon interaction in metals.