Continuous quantum measurement in spin environments

TL;DR

This paper develops a formalism for stochastic master equations to describe decoherence in quantum systems interacting with spin environments, and introduces a weak spectroscopy method to detect environment correlations and non-Markovian effects.

Contribution

It presents a new formalism for modeling decoherence in spin environments and a spectroscopy technique to identify environment correlations and non-Markovian dynamics.

Findings

Weak spectroscopy can distinguish Markovian and non-Markovian environments.

Correlated environments can induce nonlocal non-Markovian effects.

The formalism captures environment-induced decoherence dynamics.

Abstract

We derive a formalism of stochastic master equations (SME) which describes the decoherence dynamics of a system in spin environments conditioned on the measurement record. Markovian and non-Markovian nature of environment can be revealed by a spectroscopy method based on weak quantum measurement (weak spectroscopy). On account of that correlated environments can lead to a nonlocal open system which exhibits strong non-Markovian effects although the local dynamics are Markovian, the spectroscopy method can be used to demonstrate that there is correlation between two environments.