Quantum Nonlinear Sigma Model with a Damping Term; Finite Temperature Renormalization Group Analysis

We study the behavior of the finite temperature quantum nonlinear sigma model in two dimensions in the presence of the damping of the form f (|w_n|) = g|w_n|^af (|\omega_n|) = \gamma |\omega_n|^\alpha, where α satisfies a 3 1\alpha \ge 1. The analytical calculations will be performed using a = 2\alpha = 2 and the results will be compared with the standard results obtained for the standard quantum nonlinear sigma model. The behavior of such a system is connected with the pseudogap which appears in the normal state of the cuprate superconductors.