Director Fluctuations and Ising Universality at the Paranematic-Nematic Critical Point

Abstract

A statistical mechanical calculation using renormalization group analysis is carried out which shows that the paranematic-nematic critical point (PNCP) is in the same university class as the liquid-gas critical point, namely that of the Ising model. The calculation explicitly shows how the non-critical director fluctuations play an important role in providing features in the phase diagram, not present in mean-field theories, such as a non-analytic order parameter diameter (two-phase average dielectric (or magnetic) anisotropy on the coexistence curve), and confirms the predictions of the scaling theory of the PNCP.

Keywords:

• phase transition
• critical point
• paranemantic
• director fluctuations
• Ising model