The Detection of Massive Goldenstone (Higgs) Mode in Two-Dimensional Ultra-cold Atomic Lattice Systems

ORAL

Abstract

We discuss how to reveal the massive Goldstone mode, often referred to as the Higgs amplitude mode, near the Superfluid-to-Insulator quantum critical point (QCP) in a system of two-dimensional ultra-cold bosonic atoms in optical lattices. The spectral function of the amplitude response is obtained by analytic continuation of the kinetic energy correlation function calculated by Monte Carlo methods. Our results enable a direct comparison with the recent experiment [M. Endres, T. Fukuhara, D. Pekker, M. Cheneau, P. Schau{\ss}, C. Gross, E. Demler, S. Kuhr, and I. Bloch, Nature {\bf 487}, 454-458 (2012)], and demonstrate a good agreement for temperature shifts induced by lattice modulation. Based on our numerical analysis, we formulate the necessary conditions in terms of homogeneity, detuning from the QCP and temperature in order to reveal the massive Goldstone resonance peak in spectral functions experimentally. We also propose to apply a local modulation at the trap center to overcome the inhomogeneous broadening caused by the parabolic trap confinement.

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Authors

  • Kun Chen

    University of Massachusetts, Amherst; University of Science and Technology of China

  • Longxiang Liu

    University of Science and Technology of China

  • Youjin Deng

    University of Science and Technology of China; University of Massachusetts, Amherst;, University of Science and Technology of China; University of Massachusetts, Amherst

  • Manuel Endres

    Harvard University; California Institute of Technology

  • Lode Pollet

    Department of Physics, Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, University of Munich, Theresienstrasse 37, 80333 M, Ludwig Maximilian University of Munich, Department of Physics, Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilians-University Munich

  • Nikolay Prokof'ev

    Department of Physics, University of Massachusetts, Amherst, MA 01003, USA, University of Massachusetts, University of Massachusetts, Amherst;Russian Research Center “Kurchatov Institute”, UMass Amherst, University of Massachusetts, Amherst; Russian Research Center ``Kurchatov Institute"