Fractional domain walls from on-site softening in dipolar bosons

TL;DR

This paper explores the phase diagram of dipolar bosons in a 1D optical lattice, revealing stable charge-density-wave states with fractional domain walls that resemble non-Abelian fractional quantum Hall states, and discusses their experimental accessibility.

Contribution

It introduces the concept of fractional domain walls in dipolar bosons and links them to non-Abelian quantum Hall states, expanding understanding of 1D quantum phases.

Findings

Identification of stable CDW states with fractional domain walls

Presence of supersolids and superfluid regimes outside insulating phases

Feasibility of creating fractional domain walls via single-site addressing

Abstract

We study dipolar bosons in a 1D optical lattice and identify a region in parameter space---strong coupling but relatively weak on-site repulsion---hosting a series of stable charge-density-wave (CDW) states whose low-energy excitations, built from "fractional domain walls," have remarkable similarities to those of non-Abelian fractional quantum Hall states. Here, a conventional domain wall between translated CDW's may be split by inserting strings of degenerate, but inequivalent, CDW states. Outside these insulating regions, we find numerous supersolids as well as a superfluid regime. The mentioned phases should be accessible experimentally and, in particular, the fractional domain walls can be created in the ground state using single-site addressing, i.e., by locally changing the chemical potential.