  By acting on the excited states at half-filling in the positive-$U$ Hubbard
model with the $\eta$-pairing operators, we found some new superconducting
states in the Hubbard model away from half-filling. Such eigenstates are
different from the zero-pair and one-pair states introduced by Yang. It is
shown that the one-pair states are not the ground-states and possess ODLRO.

Condensed Matter