Q. - Y. Liang, Venkatramani, A. V., Cantu, S. H., Nicholson, T. L., Gullans, M., Gorshkov, A. V., Thompson, J. D., Chin, C., Lukin, M. D., and Vuletic, V.,
“Observation of three-photon bound states in a quantum nonlinear medium”,
Science, vol. 359, no. 6377, pp. 783-786, 2018.