A route to finding fractons? Rank-2 U(1) spin liquid on the breathing pyrochlore lattice

Fractons, dimensionally-challenged excitations with roots in theories 
of quantum glasses and quantum information, offer an intriguing bridge between gravity, liquid crystals, elasticity, and higher--rank generalisations of electromagnetism.

However, despite rapid progress in the understanding the phenomenology of these novel excitations, concrete proposals as to where fractons might be found in experiment remain scarce.

In this talk we show how a spin liquid, described by a rank-2 U(1) gauge theory known to support fractons, arises in a simple and realistic model of a magnet on the breathing pyrochlore lattice.

Candidate materials, and the experimental signatures of this spin liquid, are also discussed.

[1]  Han Yan, Owen Benton, L. D. C. Jaubert and Nic Shannon, Phys. Rev. Lett. 124, 127203 (2020)