FUNCTIONAL SCHRODINGER PICTURE APPROACH TO A MANY-PARTICLE SYSTEM

A new many-body theoretical scheme via the functional Schrodinger pict ure is developed for the study of condensed matter systems. Using the interacting electron gas and the Hubbard Hamiltonian as model systems, we show that the Gaussian approximation of this theory yields both th e symmetry conserving and the symmetry breaking mean field solutions w ithin the same theoretical framework. The possibility of extending thi s theoretical scheme to finite temperatures and beyond the Gaussian ap proximation is also discussed.