Discrete Time Crystals in the Absence of Manifest Symmetries or Disorder in Open Quantum Systems.

@article{Gambetta2019DiscreteTC,
  title={Discrete Time Crystals in the Absence of Manifest Symmetries or Disorder in Open Quantum Systems.},
  author={Filippo M. Gambetta and Federico Carollo and Matteo Marcuzzi and Juan P. Garrahan and Igor Lesanovsky},
  journal={Physical review letters},
  year={2019},
  volume={122 1},
  pages={
          015701
        }
}
We establish a link between metastability and a discrete time-crystalline phase in a periodically driven open quantum system. The mechanism we highlight requires neither the system to display any microscopic symmetry nor the presence of disorder, but relies instead on the emergence of a metastable regime. We investigate this in detail in an open quantum spin system, which is a canonical model for the exploration of collective phenomena in strongly interacting dissipative Rydberg gases. Here, a… 
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