Hannover 2016 – scientific programme
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A: Fachverband Atomphysik
A 9: Ultra-cold atoms, ions and BEC (with Q)
A 9.48: Poster
Monday, February 29, 2016, 16:30–19:00, Empore Lichthof
A Thouless quantum pump with ultracold bosonic atoms in an optical superlattice — •Christian Schweizer1,2, Michael Lohse1,2, Oded Zilberberg3, Monika Aidelsburger1,2, and Immanuel Bloch1,2 — 1Fakultät für Physik, LMU München, Germany — 2Max-Planck-Institut für Quantenoptik, Garching, Germany — 3Institut für Theoretische Physik, ETH Zürich, Switzerland
Topological charge pumping enables the transport of charge through an adiabatic cyclic evolution of the underlying Hamiltonian. In contrast to classical transport, the transported charge is quantized and purely determined by the topology of the pump cycle, making it robust to perturbations. Here, we report on the realization of such a pump with ultracold bosonic atoms forming a Mott insulator in a dynamically controlled optical superlattice. By taking in situ images of the cloud,we observe a quantized deflection per pump cycle. We reveal the pump's genuine quantum nature by showing that, in contrast to groundstate particles, a counterintuitive reversed deflection occurs for particles in the first excited band. Furthermore, we directly demonstrate that the system undergoes a controlled topological transition in higher bands when tuning the superlattice parameters. These results open a route to the implementation of more complex pumping schemes, including spin degrees of freedom and higher dimensions.