ANALYTIC EVALUATION OF RESONATING VALENCE BOND STATES

Expectation values of the one-particle density matrix, the Cooper-pair amplitude and the Hubbard interaction are calculated analytically within locally correlated superconducting wave functions. For weak correlations or small densities, a rapidly converging series-expansion of exact expectation values is derived, while for strong correlations a sum-rule conserving single-site approximation is developed. Explicit results for the kinetic energy of holes within resonating valence bond states are compared with corresponding Monte Carlo data. The characteristic difference between wave functions with fixed and variable particle number, respectively, is pointed out.