Quantum Channel Negativity as a Measure of System-Bath Coupling and Correlation

TL;DR

This paper introduces quantum channel negativity as a quantifiable measure of system-bath interactions, providing insights into environmental noise effects in quantum systems.

Contribution

It defines and analyzes quantum channel negativity as a tool to measure system-bath coupling and correlation, expanding understanding of quantum noise.

Findings

Negativity is computable from the Choi representation.

Negativity is always well-defined and bounded.

Negativity correlates with environmental noise effects.

Abstract

Complete positivity is a ubiquitous assumption in the study of quantum systems interacting with the environment, but the lack of complete positivity of a quantum evolution (called the "negativity") can be used as a measure of the system-bath coupling and correlation. The negativity can be computed from the Choi representation of a channel, is always defined and bounded, and can be used to understand environmentally induced noise in a quantum system.