Overlapping Resonances in the Resistance of Superposition States to Decoherence

TL;DR

This paper investigates how overlapping resonances influence the decoherence of superposition states in strongly coupled quantum systems, revealing that greater resonance overlap can enhance state purity and stability.

Contribution

It introduces a novel approach linking overlapping resonances to decoherence resistance, especially in strong coupling regimes, with analysis of spin-half particles and oscillator environments.

Findings

Greater overlapping resonances increase maximum purity.

Resonance overlap expands the range of possible purity values.

Decoherence free subspaces exhibit the largest resonance contributions.

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) amongst 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 that largest overlapping resonances contribution.