Eur. Phys. J. D 49, 257-264 (2008)
https://doi.org/10.1140/epjd/e2008-00160-9

Exact results on decoherence and entanglement in a system of N driven atoms and a dissipative cavity mode

Dipartimento di Fisica, Università di Milano, via Celoria 16, 20133 Milano, Italy

Corresponding author: ^a federico.casagrande@mi.infn.it

Received: 30 April 2008
Revised: 19 June 2008
Published online: 8 August 2008

Abstract

We solve the dynamics of an open quantum system where N strongly driven two-level atoms are equally coupled on resonance to a dissipative cavity mode. Analytical results are derived on decoherence, entanglement, purity, atomic correlations and cavity field mean photon number. We predict decoherence-free subspaces for the whole system and the N-qubit subsystem, the monitoring of quantum coherence and purity decay by atomic populations measurements, the conditional generation of atomic multi-partite entangled states and of cavity cat-like states. We show that the dynamics of atoms prepared in states invariant under permutation of any two components remains restricted within the subspace spanned by the completely symmetric Dicke states. We discuss examples and applications in the cases N=3,4.