In a delicate balance between strong interactions, weak disorder, and a periodic driving force, a collection of trapped ions qubits has been made to pulsate with a period that is relatively insensitive to the drive. This is a time crystal, where the stable pulsations emerge and break time symmetry – just like a freezing liquid breaks spatial symmetry and forms a spatial crystal. Trapped ion qubits don’t really need this added stability (they are nearly perfect on their own), but this observation may guide the stabilization of real-life solid systems, where stable quantum behavior is usually masked by defects and impurities in the system. Indeed, a similarly-prepared time crystal was also observed in color-center impurities in solid diamond at Harvard.
- Ion Trap experiment (JQI/UMD): “Observation of a Discrete Time Crystal,” J. Zhang, P. W. Hess, A. Kyprianidis, P. Becker, A. Lee, J. Smith, G. Pagano, I.-D. Potirniche, A. C. Potter, A. Vishwanath, N. Y. Yao, C. Monroe, Nature 543, 217 (2017).
- Diamond experiment (Harvard): “Observation of discrete time-crystalline order in a disordered dipolar many-body system,” S. Choi, et al., Nature 543, 221 (2017).
- Nature news article on time crystals
- JQI News Release