Particles can sometimes act like waves, and photons (particles of light) are no exception. Just as waves create an interference pattern, like ripples on a pond, so do photons. Physicists from the National Institute of Standards and Technology (NIST) and their colleagues have achieved a major new feat—creating a bizarre “quantum” interference between two photons of markedly different colors, originating from different buildings on the University of Maryland campus.
Click here for original story, Scientists correlate photon pairs of different colors generated in separate buildings
Source: Phys.org