Temporally multiplexed ion-photon quantum interface via fast ion-chain transport

TL;DR

This paper demonstrates a fast, temporally multiplexed ion-photon interface using rapid transport of a chain of calcium ions, enabling higher entanglement rates for quantum networks with minimal crosstalk.

Contribution

It introduces a novel method of rapidly transporting ion chains to achieve temporal multiplexing in ion-photon interfaces, advancing scalable quantum networking techniques.

Findings

Successfully transported nine ions across 74 μm in 86 μs

Verified non-classical photon correlations with g^{(2)}(0)=0.060(13)

Ion transport induced coherent excitation of motional modes

Abstract

High-rate remote entanglement between photon and matter-based qubits is essential for distributed quantum information processing. A key technique to increase the modest entangling rates of existing long-distance quantum networking approaches is multiplexing. Here, we demonstrate a temporally multiplexed ion-photon interface via rapid transport of a chain of nine calcium ions across 74 $\mathrm{\mu m}$ within 86 $\mathrm{\mu s}$. The non-classical nature of the multiplexed photons is verified by measuring the second-order correlation function with an average value of $g^{(2)}(0)$ = 0.060(13), indicating negligible crosstalk between the multiplexed modes. In addition, we characterize the motional degree-of-freedom of the ion crystal after transport and find that it is coherently excited to as much as $\bar{n}_\alpha\approx 110$ for the center-of-mass mode. Our proof-of-principle implementation paves the way for large-scale quantum networking with trapped ions, but highlights some challenges that must be overcome.