Detecting Non-Markovianity via Linear Entropy of Choi State

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.