Eur. Phys. J. D 54, 9-19 (2009)
https://doi.org/10.1140/epjd/e2009-00151-4

Spatial decoherence factor via the qubit-field interaction

CNISM and Dipartimento di Scienze Fisiche ed Astronomiche, Università degli Studi di Palermo, via Archirafi 36, 90123 Palermo, Italy

Corresponding author: ^a vaglica@fisica.unipa.it

Received: 16 December 2008
Revised: 24 March 2009
Published online: 21 May 2009

Abstract

We analyze the time evolution of an initial spatial coherence for a two level atom whose internal degrees of freedom interact with a single mode of a cavity field. When the qubit-field subsystem is taken as an environment, the translational dynamics experiences a decoherence process which may be encoded in a decoherence factor D. We find that the field statistics affects D through the alternative paths the system-environment may follow along their entanglement, while eventual field phase properties give rise to an imaginary part of D which is related to the atomic translation. From the decoherence perspective, we analyze the relation between the atomic momentum and the imaginary part of the atomic spatial density matrix, and some considerations on its asymptotic behavior are brought into question at the conclusion of the paper.