J. Phys. II France
Volume 4, Numéro 11, November 1994
Page(s) 2043 - 2059
DOI: 10.1051/jp2:1994246
J. Phys. II France 4 (1994) 2043-2059

Least-bias description of atomic beams

Berthold-Georg Englert, Christian Miniatura and Jacques Baudon

Laboratoire de Physique des Lasers, Institut Galilée, Université Paris-Nord, Avenue J.B. Clément, 93430 Villetaneuse, France

(Received 8 April 1994, accepted in final form 25 July 1994)

We show how an unbiased quantal description of the center-of-mass properties of an atomic beam is achieved by employing an appropriate statistical operator. A few examples with experimental relevance are treated in order to illustrate the method. We find that the quantum corrections to the classical relation between the velocity distribution and the time-of-flight signal are negligible in reasonable experimental situations. We apply the method to atoms traversing a longitudinal Stern-Gerlach interferometer where they are exposed to a magnetic field gradient for a short period. The dependence of the fringe visibility upon the strength and duration of the gradient is derived.

© Les Editions de Physique 1994