Various condensed matter Hamiltonians in terms of U(2/2) operators and their symmetry structures

Abstract

We rewrite various lattice Hamiltonian in condensed matter physics in terms of U(2/2) operators that we introduce. In this representation the symmetry structure of the models becomes clear. Especially, the Heisenberg, the supersymmetric t-J and a newly proposed high-$T_c$ superconducting Hamiltonian reduce to the same form $H=$$-t{\sum }_{<jk>}{\sum }_{ac}{X}_j^{ac}{X}_k^{ca}(-1{)}^{F(c)}$. This representation also gives us a systematic way of searching for the symmetries of the system.

13 pages, LatTeX, CCNY-HEP-92/7