> Feed: QuantumWeekly > Title: Quantum interference in time > Date: Tue, 15 Dec 2020 18:06:46 -1000 > Link: https://quantumweekly.com/post/637630264419467264 Quantum interference in time: The two researchers from ULB and the University of Cambridge have demonstrated that the impossibility to differentiate the photons emitted by an optical amplifier produces an effect that may be even more surprising. Fundamentally, the interference that occurs on a semi-transparent mirror stems from the fact that if we imagine switching the two photons on either sides of the mirror, the resulting configuration is exactly identical. With an optical amplifier, on the other hand, the effect identified by Cerf and Jabbour must be understood by looking at photon exchanges not through space, but through time.