title: Overlapping resonances in the resistance of superposition states to decoherence.
abstract: Overlapping resonances are shown to provide new insights into the extent of decoherence experienced by a system superposition state in the regime of strong system-environment coupling. As an example of this general approach, a generic system comprising spin-half particles interacting with a thermalized oscillator environment is considered. We find that (a) among the collection of parametrized Hamiltonians, the larger the overlapping resonances contribution, the greater the maximum possible purity, and (b) for a fixed Hamiltonian, the larger the overlapping resonances contribution, the larger the range of possible values of the purity as one varies the phases in the system superposition states. Systems displaying decoherence free subspaces show the largest overlapping resonances contribution.
authors.affiliation: Department of Chemistry, Chemical Physics Theory Group, and Center of Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Asoka
authors.initials: A
authors.lastname: Biswas
authors.forename: Moshe
authors.initials: M
authors.lastname: Shapiro
authors.forename: Paul
authors.initials: P
authors.lastname: Brumer