Microscopic origin of hydrodynamic equations: Derivation and consequences

We describe some recent progress in deriving autonomous hydrodynamic type equations for macroscopic variables from model stochastic microscopic dynamics of particles on a lattice. The derivations also yield the microscopic fluctuations about the deterministic macroscopic evolution. These grow, with time, to become infinite when the deterministic solution is unstable. A form of microscopic pattern selection is also found.