Delayed Choice Quantum Eraser Experiment Explained

The double slit experiment (from college days) has profound implications in understanding our position in universe and nature of reality . Our knowledge of system causes different results of how the photon will act, implying if there is any pocket of universe with information about some other part, it is enough to affect the former’s behavior. The delayed choice part of this experiment also shows that observer’s knowledge affects past events by loading up a backhistory to correlate with our knowledge. “Time” it appears to be only in our mind and not at quantum scale!