Bubble Raft Model for a Paraboloidal Crystal

TL;DR

This study explores how crystalline arrangements of soap bubbles adapt to a paraboloidal surface, revealing defect structures that align with theoretical models and proposing a new mechanism for scar formation due to curvature.

Contribution

It extends soap bubble raft experiments to curved surfaces, analyzing defect structures on paraboloids and proposing a mechanism for scar nucleation caused by Gaussian curvature.

Findings

Defect structures match theoretical predictions.

Crystalline configurations contain topological defects.

Proposed mechanism explains scar nucleation in curved geometries.

Abstract

We investigate crystalline order on a two-dimensional paraboloid of revolution by assembling a single layer of millimeter-sized soap bubbles on the surface of a rotating liquid, thus extending the classic work of Bragg and Nye on planar soap bubble rafts. Topological constraints require crystalline configurations to contain a certain minimum number of topological defects such as disclinations or grain boundary scars whose structure is analyzed as a function of the aspect ratio of the paraboloid. We find the defect structure to agree with theoretical predictions and propose a mechanism for scar nucleation in the presence of large Gaussian curvature.