 Superconducting fluctuation

A superconducting fluctuation is a variation of the superconducting order parameter about its mean value. Near a transition, transient pairing correlations can influence transport or magnetic response even when long-range phase-coherent superconductivity is absent.

This makes it necessary to distinguish a local pairing tendency from a fully established zero-resistance state. The strength and extent of fluctuation effects depend on dimensionality, disorder and the distance from the transition. A measured excess conductivity needs comparison with the normal-state background and alternative mechanisms.^[ref]