Speaker: R Pinto (pdf slides 1.3 Mb).
With S Flach.

Abstract: We analyze the spectral properties of a non-integrable quantum trimer model and use them to describe the time evolution of localized (local bond) excitations. We relate the properties of localized excitations such as their spectral intensity and their temporal evolution (survival probability and tunneling of quanta) to their degree of overlap with quantum breather states (tunneling pairs). We report on the existence of degeneracy points in the trimer eigenvalue spectrum for some values of parameters due to avoided crossings. These degeneracy points correspond to asymmetric quantum breather states which suppress the tunneling of quanta (bosons) completely.

NLDD05, Nonlinear excitations: theory and experiments, Sevilla, March 3-4, 2005.