Discrete Time Crystals: Rigidity, Criticality, and Realizations
https://physics.aps.org/featured-article-pdf/10.1103/PhysRevLett.118.030401N. Y. Yao,1 A. C. Potter,1,2 I.-D. Potirniche,1 and A. Vishwanath1,3
1: Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
2: Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA
3: Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
(Received 5 November 2016; published 18 January 2017)
Despite being forbidden in equilibrium, spontaneous breaking of time translation symmetry can occur in
periodically driven, Floquet systems with discrete time-translation symmetry. The period of the resulting
discrete time crystal is quantized to an integer multiple of the drive period, arising from a combination of
collective synchronization and many body localization. Here, we consider a simple model for a onedimensional
discrete time crystal which explicitly reveals the rigidity of the emergent oscillations as the drive
is varied. We numerically map out its phase diagram and compute the properties of the dynamical phase
transition where the time crystal melts into a trivial Floquet insulator. Moreover, we demonstrate that
the model can be realized with current experimental technologies and propose a blueprint based upon a one
dimensional chain of trapped ions. Using experimental parameters (featuring long-range interactions), we
identify the phase boundaries o