Time-dependent Gutzwiller theory for multi-band Hubbard models

We formulate a multi-band generalization of the time-dependent Gutzwiller theory. This approach allows for the calculation of general two-particle response functions, which are crucial for an understanding of various experiments in solid-state physics. As a first application, we study the momentum-and frequency-resolved magnetic susceptibility in a two-band Hubbard model. As in the case of underlying ground-state approaches, we find significant differences between the results of our method and those from a time-dependent Hartree-Fock approximation.