Theory of fluctuations in a two-band superconductor: MgB_ {2}

A theory of fluctuations in two-band superconductor MgB2 is developed. Since the standard Ginzburg- Landau approach fails in description of its properties, we generalize it based on the microscopic theory of a two-band superconductor. Calculating the microscopic fluctuation propagator, we build up the nonlocal two-band GL functional and the corresponding time-dependent GL equations. This allows us to calculate the main fluctuation observables such as fluctuation specific heat and conductivity.