  We propose a theory of optically-induced currents in dielectrics and wide-gap
semiconductors exposed to a non-resonant ultrashort laser pulse with a
stabilized carrier-envelope phase. In order to describe strong-field electron
dynamics, equations for density matrix have been solved self-consistently with
equations for the macroscopic electric field inside the medium, which we model
by a one-dimensional potential. We provide a detailed analysis of physically
important quantities (band populations, macroscopic polarization, and
transferred charge), which reveals that carrier-envelope phase control of the
electric current can be interpreted as a result of quantum-mechanical
interference of multiphoton excitation channels. Our numerical results are in
good agreement with experimental data.
