Ancillary Gaussian modes activate the potential to witness non-Markovianity

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