Bosonic resonating-valence-bond description of a doped antiferromagnet

We propose a theory for a doped antiferromagnet based on the bosonic resonating-valence-bond (RVB) description incorporating the phase string effect. Both antiferromagnetic and superconducting phase transitions occur naturally inside such a bosonic RVB phase. Two distinct metallic regions-underdoping and optimum doping-are also found to be a logical consequence; their unique features explain the recent neutron-scattering measurements in cuprates.