We report the formation of a macroscopic coherent state emerging from colliding polariton fluids. Four lasers with random relative phases, arranged in a square, pump resonantly a planar microcavity, creating four coherent polariton fluids propagating toward each other. When the density (interactions) increases, the four fluids synchronise and the topological excitations (vortex or soliton) disappear to form a single superfluid.
@article{arxiv.1802.06906,
title = {Coherent merging of counter-propagating exciton-polariton superfluids},
author = {Thomas Boulier and Simon Pigeon and Emiliano Cancellieri and Paul Robin and Elisabeth Giacobino and Quentin Glorieux and Alberto Bramati},
journal= {arXiv preprint arXiv:1802.06906},
year = {2018}
}