Fractons in effective field theories for spontaneously broken translations

TL;DR

This paper investigates fractonic modes arising from spontaneous breaking of translations and dilatations in effective field theories, revealing their unique mobility properties and connections to emergent symmetries in condensed matter systems.

Contribution

It introduces a novel class of effective field theories with fractonic modes linked to symmetry breaking, including the effects of finite charge density and higher-derivative terms.

Findings

Identification of fractonic modes with restricted mobility.

Connection between fractons and higher moment symmetries.

Alteration of fracton mobility through charge density and higher derivatives.

Abstract

We study the concomitant breaking of spatial translations and dilatations in Ginzburg-Landau-like models, where the dynamics responsible for the symmetry breaking is described by an effective Mexican hat potential for spatial gradients. We show that there are fractonic modes with either subdimensional propagation or no propagation altogether, namely, immobility. Such class of effective field theories encompasses instances of helical superfluids and meta-fluids, where fractons can be connected to an emergent symmetry under higher moment charges, leading in turns to the trivialization of some elastic coefficients. The introduction of a finite charge density alters the mobility properties of fractons and leads to a competition between the chemical potential and the superfluid velocity in determining the gap of the dilaton. The mobility of fractons can also be altered at zero density upon considering additional higher-derivative terms.