Two-photon speckle as a probe of multi-dimensional entanglement
Abstract
We calculate the statistical distribution P_2(I_2) of the speckle pattern produced by a photon pair current I_2 transmitted through a random medium, and compare with the single-photon speckle distribution P_1(I_1). We show that the purity Tr rho^2 of a two-photon density matrix rho can be directly extracted from the first two moments of P_1 and P_2. A one-to-one relationship is derived between P_1 and P_2 if the photon pair is in an M-dimensional entangled pure state. For M>>1 the single-photon speckle disappears, while the two-photon speckle acquires an exponential distribution. The exponential distribution transforms into a Gaussian if the quantum entanglement is degraded to a classical correlation of M>>1 two-photon states. Two-photon speckle can therefore discriminate between multi-dimensional quantum and classical correlations.
Keywords
Cite
@article{arxiv.0901.2232,
title = {Two-photon speckle as a probe of multi-dimensional entanglement},
author = {C. W. J. Beenakker and J. W. F. Venderbos and M. P. van Exter},
journal= {arXiv preprint arXiv:0901.2232},
year = {2009}
}
Comments
5 pages, 2 figures