  In this paper, we argue that the high-temperature superconductors do not
belong to strong correlated electron systems. It is shown that both the
two-dimensional Hubbard and t-J models are inadequate for describing high
temperature superconductivity. In our opinion, a superconducting phase should
be an energy minimum electronic state which can be described in a new framework
where the electron-electron interactions (both on-site Hubbard term and
off-site term) and the electron-phonon interaction can be completely
suppressed.

Superconductivity