Heidelberg 2015 – wissenschaftliches Programm
A 18.3: Poster
Dienstag, 24. März 2015, 17:00–19:00, C/Foyer
Ultracold bosons in lattices with long range hopping — •Jan Stockhofe1 and Peter Schmelcher1,2 — 1Zentrum für Optische Quantentechnologien, Universität Hamburg — 2The Hamburg Centre for Ultrafast Imaging
We study ultracold bosonic atoms in a tight-binding lattice with long range hopping terms. A helix lattice setup is proposed where such hoppings to far neighbors can be experimentally tuned to sizable values. In a first step, we discuss the noninteracting Bloch dynamics under the influence of a constant force . A closed expression for the propagator is given, based on which we analyze the dynamics of initially Gaussian wave packets. Our findings capture the anharmonic Bloch oscillations recently observed in photonic zigzag lattices and furthermore provide a detailed quantitative description of the crossover between center of mass oscillations for wide wave packets and left-right symmetric width oscillations for narrow single site excitations. We then turn to on-site interaction effects within a bosonic mean field framework. The long range hopping in the ensuing discrete nonlinear Schrödinger model is demonstrated to severely affect the structural and stability properties of localized excitations, such as discrete breathers.
 J. Stockhofe, P. Schmelcher, arXiv:1411.2784 (2014).