Topological superfluidity with repulsive alkaline-earth atoms in optical lattices

TL;DR

This paper proposes a method to realize topological superfluidity with fermionic atoms in optical lattices, where quantum fluctuations induce attraction and spin-orbit coupling, leading to a state hosting Majorana modes.

Contribution

It introduces a novel scheme to generate topological superfluidity using repulsive alkaline-earth atoms with different lattice potentials, leveraging quantum fluctuations for emergent attraction.

Findings

Quantum fluctuations induce effective attraction in itinerant fermions.

Topological superfluid state can be stabilized with ${}^{87}$Sr atoms.

Protocols for probing the superfluid's properties are proposed.

Abstract

Topological superfluids are of technological relevance since they are believed to host Majorana bound states, a powerful resource for quantum computation and memory. Here we propose to realize topological superfluidity with fermionic atoms in an optical lattice. We consider a situation where atoms in two internal states experience different lattice potentials: one species is localized and the other itinerant, and show how quantum fluctuations of the localized fermions give rise to an attraction and strong spin-orbit coupling in the itinerant band. At low temperature, these effects stabilize a topological superfluid of mobile atoms even if their bare interactions are repulsive. This emergent state can be engineered with ${}^{87}$Sr atoms in a superlattice with a dimerized unit cell. To probe its unique properties we describe protocols that use high spectral resolution and controllability of the Sr clock transition, such as momentum-resolved spectroscopy and supercurrent response to a synthetic (laser-induced) magnetic field.