Perturbative formalism in the t-J model: Diagrammatics and Feynman rules

摘要

The t-J model is analyzed in the context of the path-integral formalism. The starting point is the first-order Lagrangian formulation written in terms of the Hubbard operators recently developed. Subsequently, by using Functional techniques the correlation generating functional is constructed in terms of the proper effective Lagrangian of the model. Next, for small hole density and considering an antiferromagnetic background, a perturbative treatment of the effective Lagrangian is carried out, and so the diagrammatics and the Feynman rules can be found. Finally, the Feynman rules, propagators, and vertices are used to study magnetic properties. (C) 2000 Academic Press. [References: 13]