Hydrodynamic limits of finite range exclusion processes
We consider variants of the simple symmetric exclusion process (SSEP) where particles are 'large'; while in the SSEP, each lattice point is either occupied or not occupied by a single particle, in our model each particle is represented by a fixed shape, and the dynamics is so that shapes cannot overlap. In one dimension, this reduces to a finite range interaction that prevents particles from coming closer to each other than a certain distance. In this case, we prove the existence of the hydrodynamic limit, and identify the relevant macroscopic PDE, which is a porous medium equation. In two dimensions, we have no rigorous results, but instead rely on numerical simulations to approximate the diffusion matrix. Under the assumption that the hydrodynamic limit exists in two dimensions, we derive properties of the diffusion matrix based on the shape of the particles.