Chiral spin currents in a trapped-ion quantum simulator using Floquet engineering

TL;DR

This paper demonstrates how Floquet engineering in a trapped-ion quantum simulator can generate chiral spin currents by inducing magnetic fluxes through complex spin-spin interactions, with robustness against phonon excitations.

Contribution

It introduces a simple periodic driving scheme to create fluxes in a trapped-ion system, enabling the observation of chiral spin currents and showing robustness of spin dynamics against phonons.

Findings

Chiral spin currents can be generated using Floquet engineering.

Flux presence makes spin dynamics resilient to phonon excitations.

Feasibility demonstrated through small-system dynamics studies.

Abstract

The most typical ingredient of topologically protected quantum states are magnetic fluxes. In a system of spins, complex-valued interaction parameters give rise to a flux, if their phases do not add up to zero along a closed loop. Here we apply periodic driving, a powerful tool for quantum engineering, to a trapped-ion quantum simulator in order to generate such spin-spin interactions. We consider a simple driving scheme, consisting of a repeated series of locally quenched fields, and demonstrate the feasibility of this approach by studying the dynamics of a small system. An emblematic hallmark of the flux, accessible in experiments, is the appearance of chiral spin currents. Strikingly, we find that in parameter regimes where, in the absence of fluxes, phonon excitations dramatically reduce the fidelity of the spin model simulation, the spin dynamics remains widely unaffected by the phonons when fluxes are present.