Operator ordering and causality beyond the rotating wave approximation
2011 (English)In: Europhysics letters, ISSN 0295-5075, E-ISSN 1286-4854, Vol. 96, no 3, 34002- p.Article in journal (Refereed) Published
Conventional definition of the time-normal operator ordering (KELLEY P. L. and KLEINER W. H., Phys. Rev., 136 (1964) A316) is prone to causality violations (de HAAN M., Physica A, 132 (1985) 375; 397). We show that such violations disappear if this definition is amended outside the rotating wave approximation. Nonrelativistic causality of an arbitrary time-normal product turns out to be a property of quantum kinematics, while relativistic causality is demonstrated for a time-normal product of two operators under the most general assumptions about quantum dynamics (commutativity of operators at space-like intervals). This eliminates the key obstacle preventing phase-space techniques of quantum optics from being extended to arbitrary quantum fields including fermions.
Place, publisher, year, edition, pages
2011. Vol. 96, no 3, 34002- p.
IdentifiersURN: urn:nbn:se:kth:diva-51280DOI: 10.1209/0295-5075/96/34002ISI: 000296538200010ScopusID: 2-s2.0-80055034861OAI: oai:DiVA.org:kth-51280DiVA: diva2:463978
QC 201112122011-12-122011-12-122011-12-12Bibliographically approved