%0 Journal Article %J Nature (London) %D 2013 %T Attractive Photons in a Quantum Nonlinear Medium %A Ofer Firstenberg %A Thibault Peyronel %A Qi-Yu Liang %A Alexey V. Gorshkov %A Mikhail D. Lukin %A Vladan Vuletic %B Nature (London) %V 502 %P 71 %G eng %U http://dx.doi.org/10.1038/nature12512