Rotating wave approximation and entropy
Abstract
This Letter studies composite quantum systems, like atomcavity systems and coupled optical resonators, in the absence of external driving by resorting to methods from quantum field theory. Going beyond the rotating wave approximation, it is shown that the usually neglected counterrotating part of the Hamiltonian relates to the entropy operator and generates an irreversible time evolution. The vacuum state of the system is shown to evolve into a generalized coherent state exhibiting entanglement of the modes in which the counterrotating terms are expressed. Possible consequences at observational level in quantum optics experiments are currently under study.
 Publication:

Physics Letters A
 Pub Date:
 August 2010
 DOI:
 10.1016/j.physleta.2010.07.032
 arXiv:
 arXiv:1001.3944
 Bibcode:
 2010PhLA..374.3726K
 Keywords:

 Mathematical Physics;
 Quantum Physics
 EPrint:
 8 pages, 1 figure, introduction extended