  Characterizing the frequency-dependent response of amorphous systems and
glasses can provide important insights into their physics. Here, we study the
response of an electron glass, where Coulomb interactions are important and
have previously been shown to significantly modify the conductance and lead to
memory effects and aging. We propose a model which allows us to take the
interactions into account in a self-consistent way, and explore the
frequency-dependent conduction at all frequencies. At low frequencies
conduction occurs on the percolation backbone, and the model captures the
variable-range-hopping behavior. At high frequencies conduction is dominated by
localized clusters. Despite the difference in physical mechanisms at low and
high frequency, we are able to scale all numerical data onto a single curve,
using two parameters: the DC conduction and dielectric constant. The behavior
follows the universal scaling that is experimentally observed for a large class
of amorphous solids.
