Composite operators for BCS Superconductor

Abstract

The new form of the composite operator generalizing the Cooper pairs for a BCS superconductor is introduced. The approach is similar to the derivation of the composite operator of the odd - frequency superconductors. The examples of the $d_{x^2-y^2}-,d_{xy}-$ and $p-$ wave composite operators for a 2D $t-J$ model are given.

revtex, corrected version - minor changes