The Power of Poincar\'e: Elucidating the Hidden Symmetries in Focal Conic Domains

TL;DR

This paper reveals hidden Poincaré symmetries in focal conic domains of smectic liquid crystals by viewing layers as higher-dimensional projections, providing new insights into their geometry and textures.

Contribution

It introduces a novel approach leveraging Poincaré symmetry to analyze focal conic domains, enhancing understanding of their geometric structures.

Findings

Identifies Poincaré symmetry in smectic layers

Provides new geometric insights into focal conic textures

Clarifies the structure of classic focal conic patterns

Abstract

Focal conic domains are typically the "smoking gun" by which smectic liquid crystalline phases are identified. The geometry of the equally-spaced smectic layers is highly generic but, at the same time, difficult to work with. In this Letter we develop an approach to the study of focal sets in smectics which exploits a hidden Poincar\'e symmetry revealed only by viewing the smectic layers as projections from one-higher dimension. We use this perspective to shed light upon several classic focal conic textures, including the concentric cyclides of Dupin, polygonal textures and tilt-grain boundaries.