Catching Bethe phantoms and quantum many-body scars: Long-lived spin-helix states in Heisenberg magnets

ORAL

Abstract

Exact solutions for quantum many-body systems are rare and provide valuable insight to universal phenomena. Here we show experimentally in anisotropic Heisenberg chains that special helical spin patterns can have long lifetimes. This finding confirms the recent prediction of phantom Bethe states, exact many-body eigenstates carrying finite momenta yet no energy. We theoretically find analogous stable spin helices even in higher dimensions and in other non-integrable systems, where they now imply non-thermalizing dynamics associated with quantum many-body scars. We use phantom spin helices to directly measure the interaction anisotropy which has a major contribution from short-range off-site interactions that have not been observed before. Phantom helix states open new opportunities for quantum simulations of spin physics and studies of many-body dynamics.

*We acknowledge support from the NSF through the Center for Ultracold Atoms and Grant No.~1506369, the Vannevar-Bush Faculty Fellowship, and DARPA (grant number W911NF2010090). W.~W.~H.~is supported in part by the Stanford Institute of Theoretical Physics. Y.~K.~L.~is supported in part by the National Science Foundation Graduate Research Fellowship under Grant No.~1745302.

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Publication: arXiv:2110.12043
Phys. Rev. X 11, 041054

Presenters

  • Niklas Jepsen

    • Massachusetts Institute of Technology MIT

Authors

  • Niklas Jepsen

    • Massachusetts Institute of Technology MIT

  • Yoo Kyung Lee

    • Massachusetts Institute of Technology MIT

  • Hanzhen Lin

    • Massachusetts Institute of Technology MIT

  • Ivana Dimitrova

    • Harvard University

  • Yair Margalit

    • Massachusetts Institute of Technology MIT
    • Massachusetts Institute of Technology

  • Wen Wei Ho

    • Stanford University

  • Wolfgang Ketterle

    • Massachusetts Institute of Technology MIT
    • Massachusetts Institute of Technology