Dephasing in disordered conductors due to fluctuating electric fields

We develop an eikonal expansion for the cooperon to study the effect of spa ce- and time-dependent electric fields on the dephasing rate of disordered conductors. For randomly fluctuating fields with arbitrary covariance we de rive a general expression for the dephasing rate that is free of infrared d ivergencies in reduced dimensions. For time-dependent external fields with finite wavelength and sufficiently small amplitude we show that the dephasi ng rate is proportional to the square root of the electromagnetic power cou pled into the system, in agreement with data by Wang and Lindelof [Phys. Re v. Lett. 59, 1156 (1987)].