Topological Superfluid and Majorana Zero Modes in Synthetic Dimension.

Shaolong Wan,Zhong Wang,Zhongbo Yan

doi:10.1038/srep15927

Abstract

Recently it has been shown that multicomponent spin-orbit-coupled fermions in one-dimensional optical lattices can be viewed as spinless fermions moving in two-dimensional synthetic lattices with synthetic magnetic flux. The quantum Hall edge states in these systems have been observed in recent experiments. In this paper we study the effect of an attractive Hubbard interaction. Since the Hubbard interaction is long-range in the synthetic dimension, it is able to efficiently induce Cooper pairing between the counterpropagating chiral edge states. The topological class of the resultant one-dimensional superfluid is determined by the parity (even/odd) of the Chern number in the two-dimensional synthetic lattice. We also show the presence of a chiral symmetry in our model, which implies Z classification and the robustness of multiple zero modes when this symmetry is unbroken.

Highlights

In this paper we study the Cooper pairing between chiral edge modes of quantum Hall strips as a possible route toward one-dimensional (1D) topological superconductors and topological superfluids
Multiple zero modes are stable if a chiral symmetry of our model is unbroken
In the case C = 2, i.e. there are two pairs of chiral edge modes, as illustrated by the curves intersecting with the blue dotted line in Fig. (2b), the superfluid resulting from pairing the edge states is topologically trivial

Summary

Introduction

In this paper we study the Cooper pairing between chiral edge modes of quantum Hall strips as a possible route toward one-dimensional (1D) topological superconductors and topological superfluids. If there is a small Cooper pairing between these two edge modes, the system is a one-dimensional topological superfluid. In the case C = 2, i.e. there are two pairs of chiral edge modes, as illustrated by the curves intersecting with the blue dotted line in Fig. (2b), the superfluid resulting from pairing the edge states is topologically trivial.

Results

Conclusion