Higher-order and fractional discrete time crystals in Floquet-driven Rydberg atoms.

Liu, Bang; Zhang, Li-Hua; Wang, Qi-Feng; Ma, Yu; Han, Tian-Yu; Zhang, Jun; Zhang, Zheng-Yuan; Shao, Shi-Yao et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

Higher-order and fractional discrete time crystals (DTCs) are exotic phases of matter where the discrete time translation symmetry is broken into higher-order and non-integer category. Generation of these unique DTCs has been widely studied theoretically in different systems. However, no current experimental methods can probe these higher-order and fractional DTCs in any quantum many-body systems. We demonstrate an experimental approach to observe higher-order and fractional DTCs in Floquet-driven Rydberg atomic gases. We have discovered multiple n-DTCs with integer values of n = 2, 3, and 4, and others ranging up to 14, along with fractional n-DTCs with n values beyond the integers. The system response can transition between adjacent integer DTCs, during which the fractional DTCs are investigated. Study of higher-order and fractional DTCs expands fundamental knowledge of non-equilibrium dynamics and is promising for discovery of more complex temporal symmetries beyond the single discrete time translation symmetry.