Generation of Hyperentangled Photon Pairs

by Julio T. Barreiro et al. Physical Review Letters, 31 Dec 2005 We experimentally demonstrate the first quantum system entangled in every degree of freedom (hyperentangled). Using pairs of photons produced in spontaneous parametric down-conversion, we verify entanglement by observing a Bell-type inequality violation in each degree of freedom: polarization, spatial mode, and time energy. We also produce and characterize maximally hyperentangled states and novel states simultaneously exhibiting both quantum and classical correlations. Finally, we report the tomography of a 2×2×3×3 system (36-dimensional Hilbert space), which we believe is the first reported photonic entangled system of this size to be so characterized. Read more