Nonlinear fluctuation phenomena in the transport properties of superconductors

There exists a wide temperature region $({\rm Gi}T<T-T_c<T\sqrt{{\rm Gi}})$, where the influence of fluctuations on the thermodynamic properties of superconductors can be taken into account in the linear (Gaussian) approximation, while their influence on the kinetic properties is strongly nonlinear. Maki-Thompson contribution to conductivity saturates in this region. However, Aslamazov-Larkin contribution becomes even more singular. Such an enhancement is connected with the fact that nonlinear effects yield an increase in the lifetime of fluctuating pairs. Pairbreaking and energy relaxation processes can diminish the nonlinear effects.