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.
@article{arxiv.1011.6202,
title = {Projection of two biphoton qutrits onto a maximally entangled state},
author = {A. Halevy and E. Megidish and T. Shacham and L. Dovrat and H. S. Eisenberg},
journal= {arXiv preprint arXiv:1011.6202},
year = {2011}
}