ECAMP 15

Chaos and thermalization are interconnected phenomena that happen everywhere in life and play a crucial role in a wide range of scientific fields. A paradigmatic system that exhibits chaotic dynamics is a rotating pendulum that is periodically kicked, the so-called kicked rotor. Surprisingly, for its quantum variant, known as the quantum kicked rotor (QKR), quantum coherence prevents energy absorption, leading to dynamical localization (DL), which can be understood as Anderson localization in momentum space. However, it has been unclear what would happen in presence of interparticle interactions. Here, I report on the experimental observation of many-body dynamical localization (MBDL). We observe this phenomenon with a 1D strongly interacting quantum gas that is subject to a periodic drive. Starting from 2-nK samples in a compensated flat-bottom optical trap, we observe DL in a 1D QKR setting [1] as the interactions are tuned from zero to infinity, i.e., into the Tonks-Girardeau (TG) regime. After some initial evolution, the momentum distribution freezes and retains its characteristic structure as the sample is kicked periodically hundreds of times. In contrast, for random kicking, the distribution becomes uniform and loses all structure, indicating thermalization of the system, irrespective of the interaction strength. Our results give strong evidence for the fact that MBDL is the result of quantum coherence that is maintained in a 1D integrable setting.

[1] Observation of many-body dynamical localization,
Y. Guo et al., arXiv:2312.13880 (2023)