Darmstadt 2008 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 15: Quantengase (Gitter I)

Q 15.8: Talk

Tuesday, March 11, 2008, 15:45–16:00, 1C

Ultracold bosons in optical superlattices with and without disorder: A numerical approach — •Dominik Muth, Alexander Mering, and Michael Fleischhauer — Fachbereich Physik, Technische Universität Kaiserslautern, D-67663 Kaiserslautern

The time-evolving block decimation algorithm (TEBD) for one-dimensional systems and its modification for infinite size systems (iTEBD) can be used to determine the ground state for various Hamiltonians. We apply this method to determine the superfluid to Mott-insulator phase transition for a Bose-Hubbard model with a superlattice. While for small hopping parameter J the loophole-shaped insulator domains, derived by a mean-field approach [1], fit quite well to our numerical results, the results differ for large hopping as expected. Adding disorder to the system, we show that the loophole domains detach from the J=0 axis, creating insulating islands surrounded by a Bose-glass phase.

[1] P. Buonsante, A. Vezzani - Phys. Rev. A 72, 013614 (2005)