2012/02/12 by Frank Wilczek · 2 voices · 8 citations
Physics and Astronomy · #cond-mat.other #cond-mat.supr-con #quant-ph
paper · pdf · doi:10.1103/physrevlett.109.160401
6 pages, no figures. v2: tightened format, additional references, small improvements
arxiv published 2012/02/12 · arxiv created 2012/07/11 · arxiv updated 2015/06/04
Difficulties around the idea of spontaneous breaking of time translation symmetry in a closed quantum mechanical system are identified, and then overcome in a simple model. The possibility of ordering in imaginary time is also discussed.