Detecting Non-Markovianity via Linear Entropy of Choi State

TL;DR

This paper introduces a linear-entropy-based method to detect non-Markovian quantum dynamics by analyzing the Choi state's entropy, validated through a pure dephasing channel example and extendable to Rénnyi entropy.

Contribution

A novel non-Markovianity witness scheme using linear entropy of the Choi state, providing a practical detection method in quantum information science.

Findings

Effective detection of non-Markovianity via linear entropy.

Method validated with pure dephasing channel example.

Extension possible to Rénnyi entropy-based detection.

Abstract

Non-Markovian dynamics detection is one of the most popular subjects in the quantum information science. In this paper, a linear-entropy-based non-Markovianity witness scheme is constructed. The positive definiteness of the Choi state will be broken in the non-Markovian evolution, which can be witnessed by its linear entropy. Thus, the linear entropy of the Choi state can be used to witness the non-Markovian dynamics. The effectiveness of the proposed method is verified by an example of the pure dephasing channel. Also, it is shown that this method can be extended to the one based on R\'enyi entropy.