Spin pumping and measurement of spin currents in optical superlattices

TL;DR

This paper demonstrates an experimental realization of a spin pump using ultracold atoms in optical superlattices, enabling the measurement of spin currents and transport without charge movement, inspired by the quantum spin Hall effect.

Contribution

It introduces a new method to generate and detect spin currents in optical lattices, linking ultracold atom experiments with topological spin transport phenomena.

Findings

Successful implementation of a spin pump with ultracold bosons.

Novel detection method via superexchange oscillations.

Direct observation of spin transport through in-situ measurements.

Abstract

We report on the experimental implementation of a spin pump with ultracold bosonic atoms in an optical superlattice. In the limit of isolated double wells it represents a 1D dynamical version of the quantum spin Hall effect. Starting from an antiferromagnetically ordered spin chain, we periodically vary the underlying spin-dependent Hamiltonian and observe a spin current without charge transport. We demonstrate a novel detection method to measure spin currents in optical lattices via superexchange oscillations emerging after a projection onto static double wells. Furthermore, we directly verify spin transport through in-situ measurements of the spins' center of mass displacement.