Topological semimetal and superfluid of s-wave interacting fermionic atoms in an orbital optical lattice

TL;DR

This paper demonstrates how optical lattice geometry can induce topological semimetal and superfluid phases in fermionic atoms with s-wave interactions, revealing new topological states with high Chern numbers and chiral edge modes.

Contribution

It introduces a symmetry-based method to control orbital hybridization in optical lattices, leading to the discovery of topological semimetal and superfluid phases with high Chern numbers.

Findings

Robust topological semimetal at single-particle level

Topological superfluid with high Chern number (e.g., 2)

Design of an experimental scheme for realization

Abstract

Recent advanced experimental implementations of optical lattices with highly tunable geometry open up new regimes for quantum many-body states of matter that previously had not been accessible. Here we introduce a symmetry-based method of utilizing the geometry of optical lattice to systematically control topologically non-trivial orbital hybridization. Such an orbital mixing leads to an unexpected and yet robust topological semimetal at single-particle level for a gas of fermionic atoms. When considering s-wave attractive interaction between atoms as for instance tuned by Feshbach resonance, topological superfluid state with high Chern number is unveiled in the presence of on-site rotation. This state supports chiral edge excitations, manifesting its topological nature. An experimental realization scheme is designed, which introduces a systematic way of achieving a new universality class (such as Chern number of 2) of orbital-hybridized topological phases beyond geometrically standard optical lattices.