The electron gas: inclusion of antiparallel spin correlations

An electron gas with a uniform neutralizing background is the canonical model for the study of the properties of an interacting many-body system. Most treatments of this problem treat inadequately the correlations between anti-parallel spins which are expected to influence strongly certain properties of the system. Using a new variational formulation, we show how to handle the non-linearities introduced into the many-body equations by such correlations; the compressibility is lowered and the paramagnetic susceptibility enhanced.