On the following link https://physics.stackexchange.com/q...ent-two-electron-sources-instead-of-two-slits there is a discussion of the modification of double-slit experiments where two electrons sources are put in place of the slits. The conclusion is - there will be no interference in that case. I understand, the same argument should generally stay for photons, i.e. 2 (coherent) photons should not interfere in such an experiment -- so that if we conduct thousands of experiments with 2 (coherent) photons emitted simultaneously, the result screen points on which photons are absorbed will not show interference pattern. If that is right, then how two coherent laser beams (instead of 2 singular photons) may interfere?