Chiral phase from three spin interactions in an optical lattice

TL;DR

This paper investigates a spin-1/2 chain with three-spin interactions in an optical lattice, revealing diverse phases including a gapless incommensurate chiral phase and critical points related to Ising and Potts universality classes.

Contribution

It introduces a novel spin chain model with three-spin interactions in optical lattices and characterizes its complex phase diagram and critical behaviors.

Findings

Identification of phases with periods one, two, and three

Discovery of a gapless incommensurate chiral phase

Critical points in the Ising and three-state Potts universality classes

Abstract

A spin-1/2 chain model that includes three spin interactions can effectively describe the dynamics of two species of bosons trapped in an optical lattice with a triangular-ladder configuration. A perturbative theoretical approach and numerical study of its ground state is performed that reveals a rich variety of phases and criticalities. We identify phases with periodicity one, two or three, as well as critical points that belong in the same universality class as the Ising or the three-state Potts model. We establish a range of parameters, corresponding to a large degeneracy present between phases with period 2 and 3, that nests a gapless incommensurate chiral phase.