Discrete time crystals (DTCs) are exotic phases of matter characterized by robust and persistent subharmonic response of observables to a time-periodic driving. We uncover an important and rather general mechanism, made possible by the so-called Majorana $\pi$ modes (MPMs), in generating and stabilizing the DTCs in periodically driven spin-1/2 systems in a two-dimensional setting. Of particular significance is that we can increase the number of MPMs linearly with the number of spins and consequently strengthen the performance of the DTCs. Our findings not only provide a topological insight into DTCs, but also pave the way towards studies of DTC phases in higher dimension with sharper subharmonic response, by searching for a lattice configuration that maximizes the number of MPMs.Discrete time crystals (DTCs) are exotic phases of matter characterized by robust and persistent subharmonic response of observables to a time-periodic driving. We uncover an important and rather general mechanism, made possible by the so-called Majorana $\pi$ modes (MPMs), in generating and stabilizing the DTCs in periodically driven spin-1/2 systems in a two-dimensional setting. Of particular significance is that we can increase the number of MPMs linearly with the number of spins and consequently strengthen the performance of the DTCs. Our findings not only provide a topological insight into DTCs, but also pave the way towards studies of DTC phases in higher dimension with sharper subharmonic response, by searching for a lattice configuration that maximizes the number of MPMs.

Dec 7, 20200 citations

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

Bang Liu, Li-Hua Zhang, Qifeng Wang +9 more

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. Discrete-time crystal (DTC) is a special phase of matter that exhibits a spontaneous breaking of the discrete time translational symmetry. Here, Bang Liu et al. demonstrate an experimental approach to observe higher-order and fractional DTCs in Floquet-driven Rydberg atomic gases.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. Discrete-time crystal (DTC) is a special phase of matter that exhibits a spontaneous breaking of the discrete time translational symmetry. Here, Bang Liu et al. demonstrate an experimental approach to observe higher-order and fractional DTCs in Floquet-driven Rydberg atomic gases.

Nature CommunicationsNov 10, 202437 citations

Discrete time crystals in long-range interacting systems

Norman Y. Yao

Bulletin of the American Physical SocietyMar 5, 20190 citations

DYNAMICS OF NONINTEGRABLE PHASES AND PHASE TRANSITIONS IN (1+1)-DIMENSIONS

Choon-Lin Ho, Yutaka Hosotani

Jan 1, 19880 citations

Classical approaches to prethermal discrete time crystals in one, two, and three dimensions

Andrea Pizzi, Andreas Nunnenkamp, Johannes Knolle

Prethermal discrete time crystals (pDTC) are new collective nonequilibrium phases of matter that break, up to exponentially long times, the discrete time translational symmetry of a periodic drive. Previously studied as a quantum phenomenon, this paper establishes that pDTCs also emerge for classical Hamiltonian dynamics even in their `higher-order and fractional' version. This enables efficient simulations of such phenomena in experimentally relevant settings, including a study of the interplay between dimensionality and interaction range.Prethermal discrete time crystals (pDTC) are new collective nonequilibrium phases of matter that break, up to exponentially long times, the discrete time translational symmetry of a periodic drive. Previously studied as a quantum phenomenon, this paper establishes that pDTCs also emerge for classical Hamiltonian dynamics even in their `higher-order and fractional' version. This enables efficient simulations of such phenomena in experimentally relevant settings, including a study of the interplay between dimensionality and interaction range.

arXiv:2108.07272Physical review. B./Physical review. BSep 27, 202144 citations

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modes (MPMs), in generating and stabilizing the DTCs in periodically driven spin-1/2 systems in a two-dimensional setting. Of particular significance is that we can increase the number of MPMs linearly with the number of spins and consequently strengthen the performance of the DTCs. Our findings not only provide a topological insight into DTCs, but also pave the way towards studies of DTC phases in higher dimension with sharper subharmonic response, by searching for a lattice configuration that maximizes the number of MPMs.