Density Fluctuations across the Superfluid-Supersolid Phase Transition in a Dipolar Quantum Gas

ORAL

Abstract

Fluctuations are crucial to gain insights into phase transitions and elementary excitations. Here we report direct in situ measurement of the density fluctuations across the phase transition from a dipolar Bose-Einstein condensate to the supersolid state. This allows us to image the spatial pattern of the roton modes, which are the dominant contribution to the fluctuation and induce the phase transition. The extracted static structure factor features an increasing peak while approaching the transition point and reaches the maximum at the critical point, resulting from the enhanced population of the roton modes as they soften. Thermal fluctuations due to the finite temperature further enhances the static structure factor, giving rise to almost a factor of hundred compared to the zero-temperature case. On the supersolid side, the simultaneous observation of the BEC and crystal phonons is a hallmark for supersolidity.

*This work is supported by the German Research Foundation (DFG) within FOR2247 under Pf381/16-1 and Bu2247/1, Pf381/20-1, FUGG INST41/1056-1 and the QUANT:ERA collaborative project MAQS. M.G. and M.Z. acknowledge funding from the Alexander von Humboldt Foundation

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Publication: Physical Review X 11.1 (2021): 011037.

Presenters

  • Mingyang Guo

    • 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, University of Stuttgart
    • University of Stuttgart
    • 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart

Authors

  • Mingyang Guo

    • 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, University of Stuttgart
    • University of Stuttgart
    • 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart

  • Jens Hertkorn

    • 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart
    • University of Stuttgart

  • Jan-Niklas Schmidt

    • 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, University of Stuttgart
    • University of Stuttgart
    • 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart

  • Fabian Boettcher

    • 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, University of Stuttgart
    • University of Stuttgart
    • 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart

  • Matthias Schmidt

    • University of Stuttgart

  • Kevin Ng

    • 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, University of Stuttgart
    • University of Stuttgart
    • 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart

  • Hans Peter Büchler

    • Institute for Theoretical Physics III and Center for Integrated Quantum Science and Technology, Universität Stuttgart
    • University of Stuttgart

  • Tim Langen

    • 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart
    • Universtiy of Stuttgart
    • Stuttgard
    • University of Stuttgart

  • Martin W Zwierlein

    • Massachusetts Institute of Technology MIT
    • MIT-Harvard Center for Ultracold Atoms, Research Laboratory of Electronics, and Department of Physics, Massachusetts Institute of Technology

  • Tilman Pfau

    • 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
    • 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart
    • University of Stuttgart
    • 5th Institute of Physics, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany