Physical Review Letters
Exact resonating-valence-bond ground state and possibility of superconductivity in repulsive Hubbard models
Hal Tasaki
Abstract
We generalize the exactly solvable Hubbard model with infinitely large on-site Coulomb repulsion recently introduced by Brandt and Giesekus. We point out that the exact ground state can be regarded as a resonating-valence-bond state, and argue that the state may exhibit superconductivity. The existence of a phase with singlet-pair ordering is demonstrated in a simple model on a tree.