  In this review, we develop the formalism employed to describe
charge-density-wave insulators in pump/probe experiments using ultra short
driving pulses of light. The theory emphasizes exact results in the simplest
model for a charge-density wave insulator (given by a noninteracting systems
with two bands and a gap) and by employing nonequilibrium dynamical mean-field
theory to solve the Falicov-Kimball model in its ordered phase. We show both
how to develop the formalism and how the solutions behave. Care is taken to
describe the details behind these calculations and to show how to verify their
accuracy via sum-rule constraints.
