Experimental evidence for Hilbert-space fragmentation in tilted Fermi-Hubbard chains

ORAL

Abstract

Out-of-equilibrium phenomena constitute natural applications of quantum simulators based on ultracold atoms in optical lattices. We utilize them to explore fundamental questions about the thermalization of isolated quantum many-body systems. Generically, thermalization in such systems occurs according to the eigenstate thermalization hypothesis (ETH). In contrast, violation of ETH is believed to occur mainly in two types of systems: integrable models and many-body localized systems (MBL). In between these two extreme limits there is a whole range of models that exhibit more complex dynamics, for instance, due to an emergent fragmentation of the Hilbert space (HSF) into many dynamically disconnected subspaces. We have realized the tilted 1D Fermi-Hubbard model which lies at the interface of MBL and HSF and probe out-of-equilibrium dynamics in this model by preparing an initial charge-density wave state. We observe a robust memory of this initial state over a wide range of parameters. Furthermore, we find a strong initial-state dependent thermalization in the large tilt limit - a smoking-gun signature of Hilbert-space fragmentation.

*This work was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy - EXC-2111 -39081486. The work at LMU was additionally supported by DIP and B. H. M. acknowledges support from the European Union (Marie Curie, Pasquans). Moreover, the work at TU was supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No. 771537).

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Publication: S. Scherg, T. Kohlert, P. Sala, F. Pollmann, B. H. M., I. Bloch, and M. Aidelsburger, Observing non-ergodicity
due to kinetic constraints in tilted fermi-hubbard chains, arXiv:2010.12965 (2020).

Presenters

  • Sebastian Scherg

    • Ludwig-Maximilians-Universitaet (LMU-Munich)
    • Ludwig-Maximilians-Universitaet (LMU-Munich), Max-Planck Institut für Quantenoptik, Munich Center for Quantum Science and Technology (MCQST)

Authors

  • Sebastian Scherg

    • Ludwig-Maximilians-Universitaet (LMU-Munich)
    • Ludwig-Maximilians-Universitaet (LMU-Munich), Max-Planck Institut für Quantenoptik, Munich Center for Quantum Science and Technology (MCQST)

  • Thomas Kohlert

    • Ludwig-Maximilians-Universitaet (LMU-Munich)
    • Ludwig-Maximilians-Universitaet (LMU-Munich), Max-Planck Institut für Quantenoptik, Munich Center for Quantum Science and Technology (MCQST)

  • Pablo Sala de Torres-Solanot

    • TU Munich, Munich Center for Quantum Science and Technology (MCQST)

  • Frank Pollmann

    • TU Munich
    • TU Munich, Munich Center for Quantum Science and Technology (MCQST)

  • Bharath Hebbe Madhusudhana

    • Ludwig Maximilians Universitat Munchen
    • Ludwig-Maximilians-Universitaet (LMU-Munich), Max-Planck Institut für Quantenoptik, Munich Center for Quantum Science and Technology (MCQST)

  • Immanuel F Bloch

    • Max Planck Institute for Quantum Optics
    • Max Planck Institute of Quantum Optics
    • Max-Planck Institute for Quantum Optics (MPQ)
    • Ludwig-Maximilians-University Munich
    • Max Planck Institute for Plasma Physics
    • Ludwig-Maximilians-Universitaet (LMU-Munich), Max-Planck Institut für Quantenoptik, Munich Center for Quantum Science and Technology (MCQST)

  • Monika Aidelsburger

    • Ludwig-Maximilians-Universitaet (LMU-Munich)
    • Ludwig-Maximilians-Universitaet (LMU-Munich), Munich Center for Quantum Science and Technology (MCQST)