Experimental observation of weak non-Markovianity

TL;DR

This paper experimentally demonstrates weak non-Markovian dynamics in a qubit system using optical methods, revealing non-Markovian behavior without information backflow and exploring the transition to strong non-Markovianity.

Contribution

It provides the first experimental observation of weak non-Markovianity in a qubit system and analyzes the transition to strong non-Markovianity by adjusting environmental parameters.

Findings

Weak non-Markovian dynamics observed without information backflow

Transition from weak to strong non-Markovianity demonstrated

Full process tomography confirms non-Markovian behavior

Abstract

Non-Markovianity has recently attracted large interest due to significant advances in its characterization and its exploitation for quantum information processing. However, up to now, only non-Markovian regimes featuring environment to system backflow of information (strong non-Markovianity) have been experimentally simulated. In this work, using an all-optical setup we simulate and observe the so-called weak non-Markovian dynamics. Through full process tomography, we experimentally demonstrate that the dynamics of a qubit can be non-Markovian despite an always increasing correlation between the system and its environment which, in our case, denotes no information backflow. We also show the transition from the weak to the strong regime by changing a single parameter in the environmental state, leading us to a better understanding of the fundamental features of non-Markovianity.