Generalization of the Nonlinear Optical Conductivity Formalism by Using a Projection-reduction Method

摘要

Generalizing a theory of nonlinear optical conductivity introduced recently based on the standard quantum-statistical technique, we introduce new formulae for the general background, including correlated acoustic phonons, as well as impurities and optical phonons. We show rigorously how the conductivity tensor can be derived up to the second-order nonlinear term by utilizing the statedependent projection technique and the KC reduction identity.