Decoherence induced by an interacting spin environment in the transition from integrability to chaos

TL;DR

This study explores how the dynamical regime of a spin bath, from integrable to chaotic, influences the decoherence of a central spin system, revealing regime-dependent efficiency and similar complexity effects.

Contribution

It demonstrates that the bath's dynamical regime affects decoherence efficiency and time, with integrable baths causing stronger decoherence in perturbative regimes and chaotic baths in strong coupling.

Findings

Integrable baths induce stronger decoherence in perturbative regimes.

Chaotic baths lead to more efficient decoherence in strong coupling.

Decoherence time varies with the bath's dynamical regime.

Abstract

We investigate the decoherence properties of a central system composed of two spins 1/2 in contact with a spin bath. The dynamical regime of the bath ranges from a fully integrable integrable limit to complete chaoticity. We show that the dynamical regime of the bath determines the efficiency of the decoherence process. For perturbative regimes, the integrable limit provides stronger decoherence, while in the strong coupling regime the chaotic limit becomes more efficient. We also show that the decoherence time behaves in a similar way. On the contrary, the rate of decay of magnitudes like linear entropy or fidelity does not depend on the dynamical regime of the bath. We interpret the latter results as due to a comparable complexity of the Hamiltonian for both the integrable and the fully chaotic limits.