The complex fluctuation conductivity in high-TC superconductor at zero magnetic field

The time-dependent Ginzburg-Landau (TDGL) equation with thermal noise is used to calculate the complex fluctuation conductivity in high-Tc superconductor in three dimensional (3D) model at zero magnetic field. The nonlinear interaction term in the TDGL is treated within self-consistent Gaussian approximation we go beyond the often used lowest Landau level approximation.