title: Phonon-induced exciton dephasing in quantum dot molecules.
abstract: A new microscopic approach to the optical transitions in quantum dots and quantum dot molecules, which accounts for both diagonal and nondiagonal exciton-phonon interaction, is developed. The cumulant expansion of the linear polarization is generalized to a multilevel system and is applied to calculation of the full time dependence of the polarization and the absorption spectrum. In particular, the broadening of zero-phonon lines is evaluated directly and discussed in terms of real and virtual phonon-assisted transitions. The influence of Coulomb interaction, tunneling, and structural asymmetry on the exciton dephasing in quantum dot molecules is analyzed.
authors.affiliation: Institut für Physik der Humboldt-Universität zu Berlin, Newtonstrasse 15, D-12489 Berlin, Germany. muljarov@gpi.ru
authors.forename: E A
authors.initials: EA
authors.lastname: Muljarov
authors.forename: T
authors.initials: T
authors.lastname: Takagahara
authors.forename: R
authors.initials: R
authors.lastname: Zimmermann