Probing Transport and Slow Relaxation in the Mass-Imbalanced Fermi-Hubbard Model

Constraints in the dynamics of quantum many-body systems can dramatically alter transport properties and relaxation timescales even in the absence of static disorder. Here, we report on the observation of such constrained dynamics arising from the distinct mobility of two species in the one-dimensional mass-imbalanced Fermi-Hubbard model, realized with ultracold ytterbium atoms in a state-dependent optical lattice. By displacing the trap potential and monitoring the subsequent dynamical response of the system, we identify suppressed transport and slow relaxation with a strong dependence on the mass imbalance and interspecies interaction strength, consistent with eventual thermalization for long times. Our observations demonstrate the potential for quantum simulators to provide insights into unconventional relaxation dynamics arising from constraints. ; Published by the American Physical Society under the terms of theCreative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Open access publication funded by the Max Planck Society. ; We acknowledge valuable and helpful discussions with Dmitry A. Abanin, Johannes Feldmeier, Sarang Gopalakrishnan, Bharath Hebbe Madhusudhana, Markus Müller, Luis Riegger, Pablo Sala, Sebastian Scherg, and Alessandro Silva, and we are grateful to Jesper Levinsen and Meera M. Parish for helpful insights on the orbital Feshbach resonance in an optical lattice. The authors also wish to thank Alexander Impertro for technical contributions to the experiment. This project has received funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy–EXC-2111–390814868, DFG TRR80 and DFG Grant No. KN1254/2-1, the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 817482 and No. 851161), and the Technical University of ...