Relaxation, thermalization and Markovian dynamics of two spins coupled to a spin bath

TL;DR

This paper demonstrates that a carefully fitted Markovian quantum master equation can effectively model the dynamics of two spins interacting with a spin bath, capturing non-Markovian effects beyond Lindblad form.

Contribution

It introduces a fitting procedure for Markovian quantum master equations that accurately describes two-spin dynamics in a spin bath, including non-Markovian effects.

Findings

Markovian master equation fits well to numerical data

The approach captures non-Markovian effects beyond Lindblad form

Effective modeling of two-spin dynamics in a spin bath

Abstract

It is shown that by fitting a Markovian quantum master equation to the numerical solution of the time-dependent Schr\"odinger equation of a system of two spin-1/2 particles interacting with a bath of up to 34 spin-1/2 particles, the former can describe the dynamics of the two-spin system rather well. The fitting procedure that yields this Markovian quantum master equation accounts for all non-Markovian effects in as much the general structure of this equation allows and yields a description that is incompatible with the Lindblad equation.