Hidden order and symmetry protected topological states in quantum link ladders

TL;DR

This paper demonstrates that quantum link models on ladder lattices can host symmetry protected topological phases, which can be experimentally realized using fermions in optical lattices, revealing new topological states.

Contribution

It introduces a scheme to realize spin-1/2 U(1) quantum-link models in ladder geometries and identifies a symmetry protected topological phase within this setup.

Findings

Identification of SPT phase in ladder quantum-link models

Proposal for experimental realization using fermions in optical lattices

Analysis of long-range string correlations to detect topological order

Abstract

We show that whereas spin-1/2 one-dimensional U(1) quantum-link models (QLMs) are topologically trivial, when implemented in ladder-like lattices these models may present an intriguing ground-state phase diagram, which includes a symmetry protected topological (SPT) phase that may be readily revealed by analyzing long-range string spin correlations along the ladder legs. We propose a simple scheme for the realization of spin-1/2 U(1) QLMs based on single-component fermions loaded in an optical lattice with s- and p-bands, showing that the SPT phase may be experimentally realized by adiabatic preparation.