Quantum diffraction of position-momentum entangled photons from a sharp edge

Highlights: • Position-momentum entangled photons show quantum diffraction by a sharp obstacle. • Individual photon shows no diffraction pattern. • Quantum diffraction is independent of location of source. • Quantum diffraction depends on total optical distance between a sharp edge and detectors. • Experimental observations are consistent with a theoretical model. -- Abstract: In this paper, an experiment of quantum diffraction of position-momentum entangled photons from a straight sharp edge is presented. Path of a single photon of an entangled pair is partially blocked by a sharp edge whereas the other photon is detected at a stationary location without revealing the which-path information of the other photon. Quantum diffraction pattern of the sharp edge is revealed only in the correlated conditional detection of spatially separated photons and no diffraction pattern is formed in local detections of individual photons. Theoretical analysis of the quantum diffraction of position-momentum entangled photons from a sharp edge is also presented in this paper. Experimental measurements of the quantum diffraction pattern are compared with theoretically calculated quantum diffraction pattern of position-momentum entangled photons.