Schwinger-Dyson Equations-of-Motion Method for Quantum Spin-1/2

Abstract

The essential difficulty of a large portion of the strongly interacting systems can be traced down to the “noncanonicality” of the underlying operators which are used to formulate the theory, like t-J model, Hubbard-type models in the large-U limit, quantum spin, etc. We proposed a new Schwinger-Dyson equations-of-motion method to compute the dynamical correlation functions of quantum spins at zero temperature. This method can also compute all the static observables from the dynamical correlation functions. We propose that this method can formulate dynamical perturbation calculations for quantum spin-1/2 models.