Non-unital non-Markovianity of quantum dynamics

TL;DR

This paper introduces new measures to quantify the non-unital aspects of quantum dynamics and their relation to non-Markovianity, highlighting limitations of existing measures like BLP.

Contribution

It presents measures for non-unitality in quantum processes and shows their significance beyond traditional non-Markovianity measures.

Findings

BLP non-Markovianity cannot detect non-unital effects

New measures quantify non-unitality impact on quantum dynamics

Non-unitality influences infinitesimal non-divisibility

Abstract

We show that Breuer-Laine-Piilo (BLP) non-Markovianity cannot capture the dynamical information in the non-unital aspect of the quantum dynamics. Moreover, we provide a measure on the effect of the non-unitality of quantum processes on the infinitesimal non-divisibility. This measure can be used as a supplement to BLP non-Markovianity for non-unital quantum processes. A measure on the degree of the non-unital behavior of quantum processes is also given in this paper.