Fluctuations in Superconductors

In this paper I shall discuss how thermodynamic fluctuations affect the observable properties of superconductors, both above and below T. Although fluctuation effects can be observed also in such properties as electron tunneling, I shall restrict attention here to the basic hallmarks of superconductivity, perfect conductivity and perfect diamagnetism. First, I shall outline how the idealized properties of superconductors without fluctuations can be understood within the conceptual framework of the Ginzburg-Landau (GL) theory. Then I shall consider how fluctuations modify the idealized sharp transitions.