Two Experimental Tests of the Halperin-Lubensky-Ma Effect at the Nematic-Smectic-A Phase Transition

TL;DR

This paper experimentally tests the Halperin-Lubensky-Ma theory's predictions on the nematic-smectic-A phase transition in liquid crystals, revealing deviations from the theory through magnetic field effects and mixture concentration dependence.

Contribution

It provides the first quantitative experimental evidence showing deviations from the HLM theory at the nematic-smectic-A transition.

Findings

Magnetic field influences the NA transition as predicted by HLM.

Mixture concentration affects the first-order discontinuity.

Deviations from HLM theory are observed experimentally.

Abstract

We have conducted two quantitative tests of predictions based on the Halperin-Lubensky-Ma (HLM) theory of fluctuation-induced first-order phase transitions. First, we explore the effect of an external magnetic field on the nematic-smectic-A (NA) transition in a liquid crystal. Second, we examine the dependence of the first-order discontinuity as a function of mixture concentration in pure 8CB and three 8CB-10CB mixtures. We find the first quantitative evidence for deviations from the HLM theory.