A CORRELATION ESTIMATE WITH APPLICATIONS TO QUANTUM-SYSTEMS WITH COULOMB INTERACTIONS

We consider some two-body operators acting on a Fock space with either fermionic or no statistics. We prove that they are bounded below by o ne-body operators which mimic exchange effects. This allows us to comp are two-body correlations of fermionic and bosonic systems with those in Hartree-Fock, respectively Hartree theory. Applications of the ferm ionic estimate yield lower bounds for the ground state energy of jelli um at high densities and of molecules with large nuclear charges.