DOPING AN OPTIMIZED RESONANCE-VALENCE-BOND STATE - A PICTURE OF SPIN-CHARGE SEPARATION

A systematic ''loop-gas'' formalism is developed for a general study o f the resonance-valence-bond (RVB) states of a quantum antiferromagnet . At half-filling, we obtain analytic, parameter-free RVB amplitudes w hich reproduce virtually exact ground-state energy and spin excitation spectrum. A doped hole is then modeled by a holon-spinon pair moving on this optimized RVB background. Its energy is in excellent agreement with other estimates on the finite lattice for t/J less than or equal to 1. Such a pair wave function shows a finite amplitude even at infi nite separation. Spin-charge separation and vanishing quasiparticle sp ectral weight are discussed in this framework.