The current Young optical experiment induces interference between 2 waves when the two intermediary holes are opened and interference dissapears as soon as an active detection system is used to know by which hole the particle flied thru. Surprisingly, even when particles are sent one to one the interference is maintained since it is not a statistical effect but the interference of the "quantic evolution wave" with itself. But what if a not-active detection system were used ? Typically considering that the two holes of the screen are not at the same height in a gravitational filed . The effect is light but the mossbauer shift of frequency related to relativist effect changes slighlty the frequency of the light and the influence of the hole number by which the particle fly thru could be detected. What is your viewpoint about this possibilty ?