• DOI:10.1038/nature21413
• Corpus ID: 4450646

Observation of a discrete time crystal

@article{Zhang2016ObservationOA,
  title={Observation of a discrete time crystal},
  author={J. H. Zhang and Paul W Hess and A. Kyprianidis and Patrick Becker and A. C. Lee and J. Smith and Guido Pagano and Ionut-Dragos Potirniche and Andrew C. Potter and Ashvin Vishwanath and Norman Y. Yao and Christopher R. Monroe},
  journal={Nature},
  year={2016},
  volume={543},
  pages={217-220}
}

• J. Zhang, P. Hess, +9 authors C. Monroe
• Published 27 September 2016
• Physics
• Nature

Spontaneous symmetry breaking is a fundamental concept in many areas of physics, including cosmology, particle physics and condensed matter. An example is the breaking of spatial translational symmetry, which underlies the formation of crystals and the phase transition from liquid to solid. Using the analogy of crystals in space, the breaking of translational symmetry in time and the emergence of a ‘time crystal’ was recently proposed, but was later shown to be forbidden in thermal equilibrium. However, non-equilibrium Floquet systems, which are subject to a periodic drive, can exhibit persistent time correlations at an emergent subharmonic frequency. This new phase of matter has been dubbed a ‘discrete time crystal’. Here we present the experimental observation of a discrete time crystal, in an interacting spin chain of trapped atomic ions. We apply a periodic Hamiltonian to the system under many-body localization conditions, and observe a subharmonic temporal response that is robust to external perturbations. The observation of such a time crystal opens the door to the study of systems with long-range spatio-temporal correlations and novel phases of matter that emerge under intrinsically non-equilibrium conditions.