# Surface creasing of soft elastic continua as a Kosterlitz-Thouless transition

## TL;DR

This paper models surface creasing in soft elastic materials as a Kosterlitz-Thouless transition, identifying ghost fibers as quasi-particles that emerge at a critical strain, aligning with experimental observations.

## Contribution

It introduces a novel theoretical framework linking surface creasing to topological phase transitions, providing a unified explanation for crease formation and profiles.

## Key findings

- Creases arise from unbinding of ghost fiber dipoles at a critical strain.
- Predicted surface profiles match experimental data.
- Proposes further experimental validation of the model.

## Abstract

Harnessing a model from composite materials science, we show how point-like cusped surface features arise as quasi-particle excitations, termed "ghost fibers", on the surface of a homogeneous soft elastic material. These deformations appear above a critical compressive strain at which ghost fiber dipoles unbind, analogous to vortices in the Kosterlitz-Thouless transition. Finite-length creases can be described in the same framework. Our predictions for crease surface profiles and onset strain agree with previous experiments and simulations, and further experimental tests are proposed.