A new world record has been claimed for encoding information onto a binary property of light, according to researchers at the University of Illinois. By "hyper-entangling" photons--that is, using quantum entanglement with multiple degrees of freedom--Professor Paul Kwiat, doctoral candidate Julio Barreiro, and postdoctoral researcher Tzu-Chieh Wei (now at the University of Waterloo) claim to have encoded 1.63 bits per photon. The previous world's records were 1.13 bits per photon without hyper-entanglement, out of a theoretical limit of 1.58 held by Professor Anton Zeilinger at the University of Vienna (and 1.18 with h hyper-entanglement out of a theoretical limit of 2 held by Professor Harald Weinfurter at the University of Munich, Germany). By combining Hyper-entanglement and linear optics, Kwiat, Barreiro and Wei, claim that 2.81 bits per photon could be encoded to someday increase the channel capacity of satellite-to-satellite data transmissions by more than 3.5 times.
Text: http://www.eetimes.com/showArticle.jhtml?articleID=206905903
