Projection of Two Biphoton Qutrits onto a Maximally Entangled State
Ayelet Halevy, E. Megidish, Tomer Shacham, Liat Dovrat, H. S. Eisenberg · Physical Review Letters · 2011
Bell state measurements, in which two quantum bits are projected onto a maximally entangled state, are an essential component of quantum information science. We propose and experimentally demonstrate the projection of two quantum systems with three states (qutrits) onto a generalized maximally entangled state. Each qutrit is represented by the polarization of a pair of indistinguishable photons-a biphoton. The projection is a joint measurement on both biphotons using standard linear optics elements. This demonstration enables the realization of quantum information protocols with qutrits, such as teleportation and entanglement swapping.