Infinite-dimensional diffusions and depletion interaction for a model of colloids

We consider infinite-dimensional random diffusion dynamics for the Asakura–Oosawa model of interacting hard spheres of two different sizes. We construct a solution to the corresponding SDE with collision local times, analyse its reversible measures, and observe the emergence of an attractive short-range depletion interaction between the large spheres. We study the Gibbs measures associated to this new interaction, exploring connections to percolation and optimal packing.