PhD Thesis - Universität Augsburg

6 Introduction
of spin- and charge- densities induced by adding of a single particle to the ground
state of the Hubbard model in the Mott-insulating phase (half band filling) or in the
metallic phase close to it (one electron less). Even in this case of an extremely localized
initial perturbation, effects of spin-charge separation are clearly identified in
the space-time evolution of the spin and charge densities. In the first case, where the
Mott-insulating ground state serves as a “host” system, ballistic spreading of induced
spin and charge densities is observed. The speed of the charge-density propagation
is enhanced in comparison with the non-interacting case and weakly depends on the
on-site interaction strength. In contrast, the velocity of the spin-density spreading
is heavily influenced by the interaction strength. Particularly interesting is the second
case, where the induced charge density stops to propagate ballistically and the
spreading is rather subdiffusive.
• The summary and outlook close the thesis and the appendices provide examples
where an analytical solution for the time evolution of different initial states can be
still constructed.