Exciton-scattering and biexciton contributions to four-wave mixing signals in semiconductor quantum wells

Summary form only given. Four-wave mixing processes in semiconductor quantum wells have been studied intensively for many years, because they allow for a detailed investigation of ultrafast many-body processes such as quantum correlations and quantum coherences. From a theoretical point of view one can roughly divide the existing approaches into two categories: (i) fully microscopic theories based on the bandstructure and on Coulomb interactions between electrons and holes, and (ii) phenomenological few-level models.