Multiple-beam Ramsey interference and quantum decoherence

Authors
Citation
H. Mei et H. Weitz, Multiple-beam Ramsey interference and quantum decoherence, APP PHYS B, 72(1), 2001, pp. 91-99
Citations number
25
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
APPLIED PHYSICS B-LASERS AND OPTICS
ISSN journal
09462171 → ACNP
Volume
72
Issue
1
Year of publication
2001
Pages
91 - 99
Database
ISI
SICI code
0946-2171(200101)72:1<91:MRIAQD>2.0.ZU;2-C
Abstract
We study the effect of photon scattering from a path of a four-beam atomic interference setup, which is based on a cesium atomic beam and two subseque nt optical Ramsey pulses projecting the atoms onto a multilevel dark state. While in two-beam interference, any attempt to keep track of an interferin g path reduces the fringe contrast, we demonstrate that photon scattering i n a multiple-path arrangement cannot only lead to a decrease, but - under c ertain conditions - also to an increase of the interference contrast. The r esults are confirmed by a density-matrix calculation. We are aware that in all cases the "which-path" information carried away by the scattered photon s leads to a loss of information that is contained in the atomic quantum st ate. An approach to quantify this "which-path" information using observed f ringe signals is presented; it allows for an appropriate measure of quantum decoherence in multiple-path interference.