Comment on ''Minimal Surfaces, Screw Dislocations, and Twist Grain Boundaries''

TL;DR

This paper critiques a previous calculation of screw dislocation interactions in smectic A phases, arguing that the long-range interaction is attractive rather than repulsive, which impacts understanding phase transitions in chiral liquid crystals.

Contribution

It challenges prior theoretical results by showing the interaction between screw dislocations is attractive, not repulsive, affecting phase transition explanations.

Findings

Disagrees with previous positive sign of dislocation interaction

Proposes that the interaction is attractive

Implications for TGB - SmA phase transition understanding

Abstract

In a recent letter, (Phys. Rev. Lett. 82, 2892(1999); cond-mat/9808306) Kamien and Lubensky calculated the energy of the surface constructed via a linear superposition of screw dislocations in SmA phase, and obtained the positive (repulsive) sign of the long-range interaction between dislocations. We would like to object that this interaction is attractive. This conclusion can be important to explain the discontinuity of the TGB - SmA phase transition in chiral liquid crystals.