Fractons from a liquid of singlet pairs

TL;DR

This paper introduces a one-dimensional electron model with spin-singlet pair hopping that exhibits fracton-like behavior, such as localization and clustering, driven by charge and dipole conservation laws.

Contribution

It presents an exactly solvable model demonstrating how dipole conservation leads to fractonic phenomena in a simple fermionic system.

Findings

Exact solutions for ground state and excitation gaps

Localization of single-electron excitations

Clustering tendencies of particles

Abstract

Fracton phases of matter feature a variety of exciting phenomena stemming from the restricted mobility of their quasiparticles. Here we consider a model of interacting electrons in one dimension that describes hopping of spin-singlet pairs and obeys both charge and dipole conservation laws. The model contains Bethe ansatz integrable sectors which allow us to solve the ground state and calculate the exact spin and single-electron excitation gaps. We observe hallmarks of fractonic behavior, including localization of single-electron excitations and propensity to clustering. Our results demonstrate the important role of the dipole moment conservation law in a simple model of spin-1/2 fermions.