Interferometric measurement of many-body topological invariants using polarons

ORAL

Abstract

We present a scheme for the direct detection of many-body topological invariants in ultra cold quantum gases in optical lattices. We generalize single-particle interferometric schemes developed for the detection of topologically non-trivial band structures [Atala et.al., Nature Physics 9, 795 (2013)] by coupling a spin-1/2 impurity to a (topological) excitation of an interacting many-body system. Performing Ramsey interferometry in combination with Bloch oscillations of the resulting polaronic particle allows to directly detect the many body-topological invariant. In particular we consider adiabatic Thouless pumps in the super-lattice Bose-Hubbard model, which transport a quantized amount of particles across a one-dimensional lattice. In the presence of inter-atomic interactions this quantized current is given by a many-body Chern number, which can be measured using our protocol. These systems also support symmetry-protected topological phases, the invariants of which can be obtained from our protocol as well.

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Authors

  • Fabian Grusdt

    • Physics Department, Univ. of Kaiserslautern, Germany and Graduate School Materials Science in Mainz, Germany
    • Dept. of Physics \& research center OPTIMAS, University of Kaiserslautern, Germany

  • Norman Yao

    • Physics Department, Harvard University, USA

  • Dmitry Abanin

    • Perimeter Institute for Theoretical Physics, Waterloo, Canada and Institute for Quantum Computing, Waterloo, Canada

  • Eugene Demler

    • Physics Department, Harvard University, USA