Two Toy Spin Chain Models of Decoherence

TL;DR

This paper analyzes decoherence in two simplified spin chain models where a central qubit interacts with a spin bath, exploring static and dynamic coupling effects on decoherence dynamics.

Contribution

It introduces two toy models of spin chain baths with different interactions and studies their decoherence behavior under static and time-varying couplings.

Findings

Decoherence dynamics depend on bath spin interactions and coupling variations.

Spin wave effects influence decoherence in the transverse interaction model.

Static and dynamic couplings produce different decoherence timescales.

Abstract

We solve for the decoherence dynamics of two models in which a simple qubit or Central Spin couples to a bath of spins; the bath is made from a chain of spins. In model 1, the bath spins are Ising spins; in Model 2, they are coupled by transverse spin-spin interactions, and the chain supports spin waves. We look at (i) the case where the Hamiltonian is static, with a constant system/bath coupling, and (ii) where this coupling varies in time.