title: Experimental investigation of a two-qubit decoherence-free subspace.
abstract: We thoroughly explore the phenomenon of a decoherence-free subspace (DFS) for two-qubit systems. Specifically, we both collectively and noncollectively decohere entangled polarization-encoded two-qubit states using thick birefringent crystals. These results characterize the basis-dependent effect of decoherence on the four Bell states, the robustness of the DFS state against perturbations in the assumption of collective decoherence, and the existence of a DFS for each type of stable noncollective decoherence. Finally, we investigate the effects of collective and noncollective dissipation.
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801-3080, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Altepeter
authors.forename: P G
authors.initials: PG
authors.lastname: Hadley
authors.forename: S M
authors.initials: SM
authors.lastname: Wendelken
authors.forename: A J
authors.initials: AJ
authors.lastname: Berglund
authors.forename: P G
authors.initials: PG
authors.lastname: Kwiat