💠 Mach-Zehnder Interferometer

Fire single photons and discover how one particle can travel two paths at once.

Mode

Phase shift

0°

Block path

Speed

1x

Detection counts

D1

0 —

D2

0 —

Tot 0

Expected: D1 100% · D2 0%

Phase shift is 0° — waves from both paths arrive in sync at D1. Constructive interference sends every photon to D1!