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A: Fachverband Atomphysik

A 1: Ultra-cold atoms, ions and BEC I (with Q)

A 1.2: Vortrag

Montag, 18. März 2013, 11:30–11:45, B 305

Interaction induced modification of tunnelling rates in a 1D tilted optical lattice — •Florian Meinert¹, Manfred Mark¹, Emil Kirilov¹, Katharina Lauber¹, Philipp Weinmann¹, Andrew Daley², and Hanns-Christoph Nägerl¹ — ¹Institut für Experimentalphysik, Universität Innsbruck — ²Physics and Astronomy, University of Pittsburgh

Cold atoms confined in optical lattice potentials offer unique access to study condensed matter Hamiltonians, e.g. the bosonic Hubbard model. Magnetic Feshbach resonances provide high control and tunability of the interparticle on-site interaction strength allowing for the preparation of Mott insulating phases with both, attractive and repulsive interaction.

We study correlated tunnelling dynamics of degenerate bosonic Cs atoms prepared in one dimensional singly occupied Mott insulating chains. Subjecting the atoms to a linear potential gradient that is adiabatically ramped through resonance with the interaction energy results in a doublon-hole density wave order, a situation that maps onto the quantum phase transition from the paramagnetic to the anti-ferromagnetic state in the 1D transverse Ising model.

By quenching the system onto the phase transition point we initiate non-equilibrium tunnelling dynamics as detected in the number of created doubly occupied lattice sites. The observed coherent response of the system provides a direct measure of the tunnelling rate. We observe striking modification of this rate by interactions when tuned from attractive to repulsive.