Dresden 2011 – scientific programme
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A: Fachverband Atomphysik
A 15: Ultra-cold atoms, ions and BEC III (with Q)
A 15.3: Talk
Wednesday, March 16, 2011, 11:15–11:30, BAR 106
Dark solitons near the Mott-insulator–superfluid phase transition — •Konstantin Krutitsky1, Jonas Larson2,3, and Maciej Lewenstein4,5 — 1Fakultät für Physik der Universität Duisburg-Essen, Campus Duisburg, Lotharstraße 1, 47048 Duisburg, Germany — 2NORDITA, 106 91 Stockholm, Sweden — 3Department of Physics, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden — 4ICFO-Institut de Ciències de Fotòniques, 008860 Castelldefels (Barcelona), Spain — 5ICREA-Institució Catalana de Recerca i Estudis Avançats, Lluís Companys 23, 08010 Barcelona, Spain
Dark solitons of ultracold bosons in the vicinity of the Mott-insulator–superfluid phase transition are studied. Making use of the Gutzwiller ansatz we have found antisymmetric eigenstates corresponding to standing solitons, as well as propagating solitons created by phase imprinting. Near the phase boundary, superfluidity has either a particle or a hole character depending on the system parameters, which greatly affects the characteristics of both types of solitons. Within the insulating Mott regions, soliton solutions are prohibited by lack of phase coherence between the lattice sites. Linear and modulational stability show that the soliton solutions are sensitive to small perturbations and, therefore, unstable. In general, their lifetimes differ for on-site and off-site modes. For the on-site modes, there are small areas between the Mott-insulator regions where the lifetime is very large, and in particular much larger than that for the off-site modes.