Calculation of two-time Green's functions for disordered crystals

E. Kolleyd, W. Kolleyd

Ferenc Iglói, Heiko Rieger

Izo I. Abram, Robin M. Hochstrasser

Coherent states in molecular crystals are described as minimum-uncertainty superpositions of all the crystal states that can interact with light, and their amplitude decay due to the presence of disorder is calculated through the time-dependent exciton Greens function. The functional form of the decay is investigated, and different methods for its calculation are compared. The decay obtainable for the k=0 vibrational exciton in α-N2 through direct time-domain approximations provides good agreement with experimental results.

Liu Yang, Yao Ma

Peter Kopietz

The disorder averaged single-particle Green's function of electrons subject to a time-dependent random potential with long-range spatial correlations is calculated by means of bosonization in arbitrary dimensions. For static disorder our method is equivalent with conventional perturbation theory based on the lowest order Born approximation. For dynamic disorder, however, we obtain a new non-perturbative expression for the average Green's function. Bosonization also provides a solid microscopic basis for the description of the quantum dynamics of an interacting many-body system via an effective stochastic model with Gaussian probability distribution.

Jun-ichi Hori