SO4 SYMMETRY IN A HUBBARD MODEL

Abstract

For a simple Hubbard model, using a particle-particle pairing operator η and a particle-hole pairing operator ζ, it is shown that one can write down two commuting sets of angular momenta operators J and J′, both of which commute with the Hamiltonian. These considerations allow the introduction of quantum numbers j and j′, and lead to the fact that the system has SO4 = (SU2 × SU2)/Z2 symmetry. j is related to the existence of superconductivity for a state and j′ to its magnetic properties.