有限溫度下的二微系統中BCS-BEC跨越之研究

Abstract

In this article we studied the BCS-BEC crossover in two-dimensional d-wave pairing at finite temperature. We would life to calculat the relation between condensate numbers and chemical potential and then find the energy gap in superconductors. We will discuss the attractive seperable potential and the contact (hard core) potential with d-wave form. The main diffrence between d-wave and s-wave is that the d-wave is angle dependent. It will lead to a factor of 1/2 in the perturbation expansion of the hard core potential.

We analyzed the asymptotic property of the two potentials. It is showed that the pair susceptibility will diverge for some kinds of potential. That is, some of potentials is computable in mean field theory but not in the pair susceptibility method.