Collective vs. single-particle motion in quantum many-body systems: Spreading and its semiclassical interpretation in the perturbative regime
Fakultät für Physik, Universität Duisburg-Essen - Lotharstraße 1, 47048 Duisburg, Germany, EU
Accepted: 2 September 2011
We study the interplay between collective and incoherent single-particle motion in a model of two chains of particles whose interaction comprises a non-integrable part. In the perturbative regime, but for a general form of the interaction, we calculate the spectral density for collective excitations. We obtain the remarkable result that it always has a unique semiclassical interpretation. We show this by a proper renormalization procedure which allows us to map our system to a Caldeira-Leggett–type model in which the bath is part of the system.
PACS: 05.45.Mt – Quantum chaos; semiclassical methods / 21.60.Ev – Collective models
© EPLA, 2011