Regensburg 2007 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 11: Superfluidity and Bose-Einstein condensation
DY 11.3: Talk
Tuesday, March 27, 2007, 10:15–10:30, H2
Complex Dynamics in Systems of Interacting Bosons — •Moritz Hiller1,2, Joshua Bodyfelt3, Tsampikos Kottos1,3, and Theo Geisel1,2 — 1Max-Planck-Institut für Dynamik und Selbstorganisation, D-37073 Göttingen — 2Fakultät für Physik, Universität Göttingen, D-37077 Göttingen — 3Department of Physics, Wesleyan University, CT-06459 Middletown, USA
We consider interacting bosons described by a Bose-Hubbard Hamiltonian (BHH) and analyze the evolving energy distribution as an experimentally controllable parameter, the coupling strength k between neighboring sites, is changed. Three driving schemes of k are considered: (a) the sudden limit (LDoS analysis), (b) the one-pulse scheme (wavepacket dynamics), and (c) the time-reversal scheme (fidelity). We find in all cases two distinct regimes: the Linear Response regime where we can trust the Fermi-Golden-Rule picture, and what we call the non-perturbative regime where the perturbation k is quantum mechanically large. In the former regime, the evolving distribution can be described by an improved Random Matrix Theory (RMT) which takes into accont the structured energy landscape of the perturbation operator. Instead, in the latter regime, non-universal features of the underlying classical dynamics dictate the energy spreading thus leading to a clash with the predictions of RMT. Our results are relevant to a vast number of experimental realizations of the BHH, like condensate systems in optical lattices and intra-molecular energy flow of vibrational degrees of freedom.