The Two - Dimensional Attractive Hubbard Model: Highly Non-Linear Superconductivity With Sum Rules

J. J. Rodriguez - Nunez, C. E. Cordeiro, A. Delfino

We use the moment approach of Nolting (exact sum rules) (Z. Physik 255, 25 (1972)) for the attractive Hubbard model in the superconducting phase. Our diagonal and off - diagonal sp…