Emergent Dipole Gauge Fields and Fractons

TL;DR

This paper develops a gauge field-based duality framework for 2D elasticity, including defects and incommensurate crystals, revealing defect dynamics and mobility restrictions in a unified manner.

Contribution

It introduces a gauge field formulation of fracton-elasticity duality applicable to various 2D materials, including twisted bilayer graphene and quasicrystals, incorporating all defect types.

Findings

Unified gauge field description of elasticity defects

Derivation of defect mobility restrictions from gauge invariance

Application to incommensurate and moiré materials

Abstract

We present a realization of fracton-elasticity duality purely formulated in terms of ordinary gauge fields, encompassing standard elasticity and incommensurate crystals as those describing twisted bilayer graphene, quasicrystals or more general moir\'e lattices. Our construction comprises a description of all types of two-dimensional defects: disclinations, dislocations, discompressions and point-like defects, and takes into account body forces and impurities. The original form of the duality in terms of tensor gauge fields is recovered after partial gauge fixing. We identify the coupling of each type of defect to the dual gauge fields, and from gauge invariance we derive generalized continuity equations for the defect currents and the expected mobility restrictions of elasticity defects.