MICROCANONICAL SIMULATION OF 1ST-ORDER PHASE-TRANSITIONS IN FINITE VOLUMES

Microcanonical studies of first-order phase transitions provide essentially the same information as canonical ensemble calculations, and offer no significant advantage over the more common canonical approach. Interpretation of the S-shaped energy-temperature curve that signals a first-order transition as a "van der Waals" curve whose extrema denote "limits of metastability" and bracket an accessible "unstable phase" is unjustified; a simple model of finite-volume effects reproduces such S-shaped curves with good accuracy, as illustrated by the three-dimensional three-state Potts model.