Reveal non-Markovianity of open quantum systems via local operations

TL;DR

This paper introduces a new method to detect non-Markovian behavior in open quantum systems by applying local operations, revealing memory effects that are otherwise hidden, and aiding in quantum coherence protection.

Contribution

It proposes a novel criterion for non-Markovianity detection using local unitary operations, enhancing understanding and control of quantum system-environment interactions.

Findings

Local operations influence system evolution due to bath memory

Non-Markovianity can be revealed without full environment knowledge

Method aids in quantum coherence protection

Abstract

Non-Markovianity, as an important feature of general open quantum systems, is usually difficult to quantify with limited knowledge of how the plant that we are interested in interacts with its environment-the bath. It often happens that the reduced dynamics of the plant attached to a non-Markovian bath becomes indistinguishable from the one with a Markovian bath, if we left the entire system freely evolve. Here we show that non-Markovianity can be revealed via applying local unitary operations on the plant-they will influence the plant evolution at later times due to memory of the bath. This not only provides a new criterion for non-Markovianity, but also sheds light on protecting and recovering quantum coherence in non-Markovian systems, which will be useful for quantum-information processing.