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arXiv · 2207.01649

Ancillary Gaussian modes activate the potential to witness non-Markovianity

Dario De Santis·Donato Farina·Mohammad Mehboudi·Antonio Acín
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Abstract

We study how the number of employed modes impacts the ability to witness non-Markovian evolutions via correlation backflows in continuous-variable quantum dynamics. We first prove the existence of non-Markovian Gaussian evolutions that do not show any revivals in the correlations between the mode evolving through the dynamics and a single ancillary mode. We then demonstrate how this scenario radically changes when two ancillary modes are considered. Indeed, we show that the same evolutions can show correlation backflows along a specific bipartition when three-mode states are employed, and where only one mode is subjected to the evolution. These results can be interpreted as a form of activation phenomenon in non-Markovianity detection and are proven for two types of correlations, entanglement and steering, and two classes of Gaussian evolutions, a classical noise model and the quantum Brownian motion model.

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Dario De Santis, Donato Farina, Mohammad Mehboudi, Antonio Acín. 2022-07-04. Ancillary Gaussian modes activate the potential to witness non-Markovianity. https://doi.org/10.1088/1367-2630/acba3a

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