We introduce the concept of Shannon dimensionality D as a new way to quantify bipartite entanglement as measured in an experiment. This is applied to orbital-angular-momentum entanglement of two photons, using two state analyzers composed of a rotatable angular-sector phase plate that is lens-coupled to a single-mode fiber. We can deduce the value of D directly from the observed two-photon coincidence fringe. In our experiment, D varies between 2 and 6, depending on the experimental conditions. We predict how the Shannon dimensionality evolves when the number of angular sectors imprinted in the phase plate is increased and anticipate that D = 50 is experimentally within reach.
@article{arxiv.0808.3325,
title = {Shannon dimensionality of quantum channels and its application to photon entanglement},
author = {J. B. Pors and S. S. R. Oemrawsingh and A. Aiello and M. P. van Exter and E. R. Eliel and G. W. 't Hooft and J. P. Woerdman},
journal= {arXiv preprint arXiv:0808.3325},
year = {2009}
}
Comments
4 pages, 3 figures, accepted for Physical Review Letters