The external-field approximation in quantum optics

✍ Scribed by R. Samson; A. Ben-Reuven

• Publisher: Elsevier Science
• Year: 1975
• Tongue: English
• Weight: 331 KB
• Volume: 36
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(75)80294-6

✦ Synopsis

A canonical transformation is presented in which the effect of a coherent, classiul, cxlemally applied field (represcr!:ed by B GIauber coherent state) is transferred from the boundny conditions to the hamiltonian, resulring in the addition of an external, chssiul field to the hamiltonian, whtic still retaining in it ihc effect of internal radiation fields in a secondquanttied form. This procedure justifies the use of the external-field approximation in czzs where internal-radiation Lffects hnvc to be retained to all orders in the correlation functions. Examples of such cttses are (a) radiative damping of a collisionbroadened molecular sample and (b) long-nuge correlations in near-critic21 conditions where retardation effects prevail in the intermolecul~ forces.