The spin susceptibility pseudogap due to Gaussian pairing in three dimensions

Abstract

We study the normal state of a short coherence length superconductor in three dimensions. Of interest is the development of a pseudogap in the spin susceptibility due to strong pair correlations. We show that this suppression of the density of states occurs even for attraction that is too weak to support two-body bound states, and this effect thus cannot be attributed to pre-formed pairs. Further, we compare the scale T* at which the susceptibility is depressed with T _c and with the mean-field transition temperature.