Importance of bath dynamics for decoherence in spin systems

TL;DR

This paper investigates how the connectivity and dynamics of a chaotic spin-bath environment influence decoherence in a coupled spin system, revealing different relaxation behaviors based on bath properties.

Contribution

It demonstrates the crucial role of bath connectivity and dynamics in decoherence, confirming that chaotic baths lead to exponential relaxation and pointer states are eigenstates under weak interactions.

Findings

Two-step decoherence occurs in slow or static baths.

Chaotic baths induce exponential relaxation.

Pointer states are eigenstates with weak interactions.

Abstract

We study the decoherence of two coupled spins that interact with a chaotic spin-bath environment. It is shown that connectivity of spins in the bath is of crucial importance for the decoherence of the central system. The previously found phenomenon of two-step decoherence (Phys. Rev. Lett. {\bf 90}, 210401 (2003)) turns out to be typical for the bath with a slow enough dynamics or no dynamics. For a generic random system with chaotic dynamics a conventional exponential relaxation to the pointer states takes place. Our results confirm a conjecture of Paz and Zurek (Phys. Rev. Lett. {\bf 82}, 5181 (1999)) that for weak enough interactions the pointer states are eigenstates of the central system.