Optomechanical Self-Structuring and Brownian-Mean-Field Phase Transitions

Graeme Campbell

Optomechanical self-structuring is the physical phenomenon of spontaneous spatial synchronisation of atoms in a cold atomic gas when illuminated by coherent laser light. This has been observed experimentally in a 2D cloud of Rubidium atoms illuminated by a uniform pump field with a single feedback mirror. We derive a simple model governing the positions and momenta of cold atoms whose interactions are mediated by light. These equations reduce to the Kuramoto model in the presence of fluctuations, inertia and damping. Conditions for the observation in self-structuring experiments of second order phase transitions typical of the Brownian Mean-Field model are derived and discussed.