Berlin 2014 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 32: Poster: Quantum gases, ultracold atoms and molecules

Q 32.34: Poster

Wednesday, March 19, 2014, 16:30–18:30, Spree-Palais

Mott insulator to superfluid transition of ultracold bosons in an optical lattice by periodic driving — •Christoph Sträter and André Eckardt — Max-Planck-Institut für Physik komplexer Systeme, Dresden

We study the hybridization of Bloch bands of ultracold quantum gases in optical lattice potentials. To overcome the band gap between the lowest Bloch band and higher excited bands, we consider a scheme where the lattice is driven by an external time-periodic force. By the resulting AC-force on the particles, the bands are coupled coherently and thus hybridize. With the help of Floquet theory we derive effective time-independent Hubbard models describing the band-coupled system. Within this framework we study the melting of a bosonic Mott-insulator as a result of the coherent band coupling. We analyze the respective phase diagram of the bosonic ground state and in addition simulate an experimental protocol, in which the phase transition is achieved by an adiabatic tuning of the driving frequency.