Time Crystals
Time Crystals are systems or phases of matter that manifest spontaneous activity. Frank, in collaboration with Al Shapere, introduced and named this concept in 2012. At present is intense, exciting ferment, both theoretical and experimental, in this area. [More on time crystals: pioneering papers; popular article; technical review; graphics]
More on Time Crystals
Pioneering papers:
Classical Time Crystals (with A. Shapere), Phys. Rev. Lett. 109, 160402 (2012). cond-mat.other 1202.2537 [MIT-CTP 4347] PDF
Quantum Time Crystals, Phys Rev. Lett. 109, 160401 (2012) quant-ph 1202.2539 [MIT-CTP 4348].
Popular article:
Crystals in Time. Scientific American 321, 5, 28-36 (2019). doi:10.1038/scientificamerican1119-28. PDF
Discrete Time Crystals:
"Colloquium: Quantum and classical discrete time crystals” (with Michael P. Zaletel, Mikhail Lukin, Christopher Monroe, Chetan Nayak, and Norman Y. Yao). Rev. Mod. Phys. 95, 031001 – Published 7 July 2023. PDF