Hyperentanglement-assisted Bell-state analysis

We propose a simple scheme for complete Bell-state measurement of photons using hyperentangled states—entangled in multiple degrees of freedom. In addition to hyperentanglement, our scheme requires only linear optics and single photon detectors, and is realizable with current technology. At the cost of additional classical communication, our Bell-state measurement can be implemented nonlocally. We discuss the possible application of these results to quantum dense coding and quantum teleportation.