From quantum many-body scars to time crystals: entanglement steering via periodic driving



IST Austria

April 23, 2021 11:00 AM

In my talk I will discuss a new mechanism of the weak ergodicity breaking relevant for the experimentally realized Rydberg-atom quantum simulators [1]. This mechanism arises from the presence of special eigenstates in the many-body spectrum that are reminiscent of quantum scars in chaotic non-interacting systems [2]. After review of different mechanisms that lead to scars, I will discuss more recent experiments [3] that demonstrated that coherent revivals associated with quantum many-body scars can be stabilized by periodic driving, generating stable subharmonic responses over a wide parameter regime. I will propose a simple model which explains experimental phenomena by spatiotemporal ordering in an effective Floquet unitary, corresponding to discrete time-crystalline (DTC) behavior in a prethermal regime. Unlike conventional DTC, the subharmonic response exists only for Neel-like initial states, associated with quantum scars. I will discuss robustness to perturbations and identify emergent timescales that could be observed in future experiments.

[1] H. Bernien, et al., Nature 551, 579–584 (2017), arXiv:1707.04344
[2] C. J. Turner et al., Nature Physics (May 2018), arXiv:1711.03528 and Phys. Rev. B 98, 155134 (2018) arXiv:1806.10933
[3] D Bluvstein, et al., arXiv:2012.12276
[4] N Maskara, A A Michailidis, WW Ho, D Bluvstein, S Choi, M D Lukin, M Serbyn, arXiv:2102.13160