We present experimental demonstration of quadrature and polarization entanglement generated via the interaction between a coherent linearly polarized field and cold atoms in a high finesse optical cavity. The non linear atom-field interaction produces two squeezed modes with orthogonal polarizations which are used to generate a pair of non separable beams, the entanglement of which is demonstrated by checking the inseparability criterion for continuous variables recently derived by Duan et al. [Phys. Rev. Lett. 84, 2722 (2000)] and calculating the entanglement of formation [Giedke et al., Phys. Rev. Lett. 91, 107901 (2003)].
@article{arxiv.quant-ph/0306152,
title = {Continuous variable entanglement using cold atoms},
author = {Vincent Josse and Aurelien Dantan and Alberto Bramati and Michel Pinard and Elisabeth Giacobino},
journal= {arXiv preprint arXiv:quant-ph/0306152},
year = {2009}
}