Each atom therefore has a choice of entering one of the boxes before passing through a slit. The box that contains a photon indicates the slit through which the atom passed. The screen instead displays a random series of dots, as it sprayed by shotgun pellets. Yes, predicted Marlan 0. Am December 19941.
Excited atoms are fragile and easily destroyed.
The Innsbruck researchers sidestepped the issues by using photons rather than atoms as interfering objects. A mirror behind the crystal reflected the laser beam back through the crystal, giving it another opportunity to create photon pairs. Each photon of the pair went off in separate directions, where both were ultimately recorded by a detector. Strategically placed mirrors reflect the photons in such a way that it is impossible to tell whether the direct or reflected laser beam created them. They correspond to the two paths that an atom traversing a double slit can take.