Fluctuation and Dissipation in Classical Many-Particle Systems

Coarse-grained Langevin-type effective field equations are derived for classical systems of particles. These equations include the effects of thermal fluctuation and dissipation which may arise from coupling to an external bath, as in the Brownian motion of a single particle, or which may arise from statistical fluctuations in small parts of an isolated many-particle system, as in sound waves. These equations may provide some guidance for the analysis of mesoscopic or microscopic molecular systems, or for systems of hundreds to thousands of subatomic particles produced in high energy nuclear collisions.