The minimum evolution time between multi-qubit quantum states is estimated for non-Markovian channels. We consider the maximally coherent pure and mixed as well $X$ initial discuss impact of coherence behaviour on their speed both dephasing dissipative processes. role non-zero value under information backflow conditions non-unital process revealed by flow limit ($\tau_{QSL}$). trade-off mixedne...

Interferometry has been used widely in sensing application. However, the technique is limited by finite coherence time of light sources when interference paths are not balanced. Higher-order effects involve intensity correlations between multiple detectors and may have advantage over traditional second-order effect exhibited only one detector. We discuss various scenarios with unbalanced delays...