Decoherence through Spin Chains: Toy Model

TL;DR

This paper demonstrates how exponential decay behavior typical of open quantum systems can emerge from the closed dynamics of a spin-1/2 chain, highlighting key conditions like large environments and weak coupling.

Contribution

It shows that closed quantum systems can exhibit open-system-like decoherence through specific conditions, bridging the gap between closed and open quantum dynamics.

Findings

Exponential decay can arise from closed spin chain dynamics.

Large environment and weak system-environment coupling are essential.

The model provides insights into decoherence mechanisms.

Abstract

The description of the dynamics of closed quantum systems, governed by the Schroedinger equation at first sight seems incompatible with the Lindblad equation describing open ones. By analyzing closed dynamics of a spin-1/2 chain we reconstruct exponential decays characteristic for the latter model. We identify all necessary ingredients to efficiently model this behavior, such as an infinitely large environment and the coupling to the system weak in comparison to the internal couplings in the bath.