Discrete time-crystalline order in black diamond: realization and probe of quantum many-body dynamics*

Strongly interacting solid-state spin ensembles provide a promising platform to explore quantum many-body physics. In particular, Nitrogen-Vacancy (NV) centers in diamond are appealing as they exhibit excellent spin properties even at room temperature. In this talk, I will present how a high-density NV ensemble can be used to investigate out-of-equilibrium quantum many-body phenomena. In particular, I will discuss the recent experimental observation of discrete time-crystalline (DTC) order: a nonequilibrium order characterized by a spontaneous breaking of time-translational symmetry and manifested in robust, long-lived subharmonic responses of a periodically driven system [1]. By engineering different types of effective interactions, we find that the spin ensemble can exhibit a long-lived robust subharmonic response over a wide range of parameters. Additional systematic investigation of the lifetime of the DTC response reveals three different regimes of relaxation dynamics, that can be continuously varied from disorder-induced slow thermalization, to driving assisted relaxation, and ultimately to universal Markovian dynamics [2]. These results highlight the utility of high-density NV ensembles as a probe of many-body dynamics and thermalization, an important aspect in the quest for the understanding and control of quantum matter, and may enable novel applications in quantum simulation and metrology with strongly correlated quantum matter [3].

[1] S. Choi et al, Nature 543, 221–225 (2017)
[2] J. Choi et al, arXiv:1806.10169 (2018)
[3] S. Choi et al, arXiv:1801.00042 (2018)