Interaction-induced chiral p_x \pm i p_y superfluid order of bosons in an optical lattice

TL;DR

This paper demonstrates the emergence of chiral p_x ± i p_y superfluid order in bosons within an optical lattice, using experimental evidence and theoretical modeling to emulate unconventional superfluidity akin to complex superconductors.

Contribution

It provides the first strong experimental evidence for interaction-driven chiral p-wave superfluid order in an optical lattice, supported by quantitative agreement with a multi-band Hubbard model.

Findings

Evidence of p_x ± i p_y superfluid order in bosons

Excellent agreement between experiment and Hubbard model

Interaction-driven emergence of unconventional superfluid order

Abstract

The study of superconductivity with unconventional order is complicated in condensed matter systems by their extensive complexity. Optical lattices with their exceptional precision and control allow one to emulate superfluidity avoiding many of the complications of condensed matter. A promising approach to realize unconventional superfluid order is to employ orbital degrees of freedom in higher Bloch bands. In recent work, indications were found that bosons condensed in the second band of an optical chequerboard lattice might exhibit p_x \pm i p_y order. Here we present experiments, which provide strong evidence for the emergence of p_x \pm i p_y order driven by the interaction in the local p-orbitals. We compare our observations with a multi-band Hubbard model and find excellent quantitative agreement.