RAYLEIGH-RITZ VARIATIONAL APPROXIMATION AND SYMMETRY NONRESTORATION

The investigation of symmetry nonrestoration scenarios has led to a co ntroversy, with certain nonperturbative approximation schemes giving i ndications in sharp disagreement with those found within conventional perturbation theory. A Rayleigh-Ritz variational approach to the probl em, which might be useful in bridging the gap between perturbative and nonperturbative viewpoints, is here proposed. As a first application, this approach is used in the investigation of a Z(2) x Z(2)-invariant thermal field theory with two scalar fields, placing particular empha sis on the region of parameter space that has been claimed to support symmetry nonrestoration.