Relation between Feynman Cycles and OffDiagonal LongRange Order
Abstract
The usual order parameter for BoseEinstein condensation involves the offdiagonal correlation function of Penrose and Onsager, but an alternative is Feynman’s notion of infinite cycles. We present a formula that relates both order parameters. We discuss its validity with the help of rigorous results and heuristic arguments. The conclusion is that infinite cycles do not always represent the Bose condensate.
 Publication:

Physical Review Letters
 Pub Date:
 October 2006
 DOI:
 10.1103/PhysRevLett.97.170601
 arXiv:
 arXiv:condmat/0604005
 Bibcode:
 2006PhRvL..97q0601U
 Keywords:

 05.70.Fh;
 03.75.Hh;
 05.30.Jp;
 Phase transitions: general studies;
 Static properties of condensates;
 thermodynamical statistical and structural properties;
 Boson systems;
 Condensed Matter  Statistical Mechanics;
 Mathematical Physics;
 Mathematics  Mathematical Physics
 EPrint:
 5 pages