# Why is it called fluctuation conductivity in superconductors?

Why is it called "fluctuation conductivity" in superconductors?

Hello,

In the work of Aslamazov-Larkin and many more, conductivity of a superconductor is calculated from the time dependent Ginzburg-Landau (TDGL) theory. They call it "fluctuation conductivity" bellow and above critical temperature. Then, this fluctuation conductivity must be added to the conductivity that comes from BCS theory known as Mattis-Bardeen complex conductivity to give the full conductivity.

Now my question:

Why is not that "fluctuation conductivity" the full conductivity?

Should not TDGL be able to give the full conductivity? Of course, considering the limitation of TDGL as an approximation. It seems that TDGL just gives the correction. Why?

Thank you!