Fluctuation phenomena in layered superconductors

Gaussian fluctuations in layered superconductors have been the subject of study for many years. Although the FD was studied in detail long ago, the FC (fluctuation conductivity) was studied only recently, since the MT and DOS diagrams were previously neglected. Recent comparisons with experiment on YBCO have shown that the DOS diagrams are important and can lead to qualitatively different behaviors for the FC parallel and perpendicular to the layers. In both cases, Gaussian fluctuations fit the data above Tc very well, even for YBCO. To date, nearly all calculations of fluctuation quantities were for B parallel c. Nevertheless, it should be possible to treat an arbitrary B, but the evaluation of the required matrix elements for the fluctuation quantities will be more complicated