Thermodynamics near the correlation volume.

Abstract

I present and test three simple thermodynamic fluctuation rules which may in some cases hold for subsystems of infinite systems with volumes less than the correlation volume. Tests at volumes near the correlation volume are made in the two-dimensional square ferromagnetic Ising model by Monte Carlo simulation. Fluctuations into the metastable and spinodal regions are discussed. Aside from difficulties apparently resulting from the small volumes used in the simulations, the rules are found to work well.