The Ginzburg Criterion Applied to a Weak First Order Phase Transition

Abstract

The range of validity of a mean field theory near a second order phase transition can be estimated using the Ginzburg criteria. Previous attempts to apply this principle to weakly first order transitions such as the nematic-isotropic transition fail to simplify to the form of the Ginzburg criteria for a second order transition and also predict fluctuations becoming less significant as the transition is approached. I calculate a Ginzburg criteria in the nematic phase that simplifies to the accepted solution as the transition becomes second order.

Key Words:

• mean field theory
• Landau theory