THE INSEPARABILITY OF RESONATING VALENCE-BOND AND ON-SITE PAIRING LONG-RANGE ORDERS IN DOPED HUBBARD MODELS

The concept of the resonating valence bond (RVB) state was originally proposed by Anderson for the ground state of the positive-U Hubbard mo del. However, the on-site pairing long-range order is expected to exis t in the ground state of the negative-U Hubbard and to be incompatible with the RVB order. In this article, we shall rigorously prove that, in fact, these two long-range orderings either coexist or are suppress ed simultaneously in the global ground states of the doped Hubbard mod els.