Path Integral Treatment of Fluctuations in the BCS-BEC Crossover in Superfluid Fermi Gases
arXiv:cond-mat/0504600
Abstract
By using a Path Integral formalism, we study the fluctuating fields in the order parameter for a 3D uniform Fermi gas at T<Tc. The BCS-BEC crossover condition is included into the analysis in the framework of the usual s-wave scattering approximation. The general expressions for the temperature dependence of the partition function and the quadratic average in the fluctuations fields are explicitly established in terms of the BCS-Gor'kov correlation propagators.
arXiv comment28 pages, 1 figure. Typos corrected. Final expression in appendix B fully explained