Calculation of the staggered spin correlation in the framework of the Dyson-Schwinger approach

Based on the linear response of the fermion propagator with respect to an external field, we first derive a model-independent expression for the staggered spin susceptibility in which the influence of the full pseudoscalar vertex function is included. This expression for the staggered spin susceptibility is quite different from that given in the previous literature. The numerical values of the staggered spin susceptibility are calculated within the framework of the Dyson-Schwinger approach. Our numerical result shows that the nonperturbative dressing effects on the fermion propagator is very important when one studies the staggered spin susceptibility which corresponding to antiferromagnetic correlation in both Nambu phase and Winger phase.