Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 41: Matter at Low Temperature: Quantum Liquids, Bose-Einstein-Condensates, Ultra-cold Atoms
TT 41.4: Vortrag
Donnerstag, 26. März 2009, 14:45–15:00, HSZ 105
Magnetism, coherent many-particle dynamics, and relaxation with ultracold bosons in optical superlattices — •Thomas Barthel1, Christian Kasztelan1, Ian P. McCulloch2, and Ulrich Schollwöck1 — 1Institute for Theoretical Physics C, RWTH Aachen University, 52056 Aachen, Germany — 2School of Physical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
We study a particular setup of an ultracold two-species boson gas in an optical superlattice. This realizes in a certain parameter regime actually the physics of spin-1/2 Heisenberg magnets describing the second order hopping processes.
Tuning of the superlattice allows for controlling the effect of fast first order processes versus the slower second order ones.
We provide the evolution of typical experimentally available observables by means of the density-matrix renormalization-group method. The validity of the description via the Heisenberg model is studied numerically and analytically.
Contrary to the case of isolated double wells which was recently realized experimentally, here, relaxation of local observables can be observed.
The tunability between the Bose-Hubbard model and the Heisenberg model in this setup could be used to study experimentally the differences in equilibration processes for nonintegrable and Bethe ansatz integrable models.
Ref. arXiv:0809.5141.