Quantum networking with trapped ions in optical cavities

Envisioned quantum networks [1] would open up powerful new applications in information security, distributed computing, precision sensing, and timekeeping. These applications require distributed quantum network nodes that, first, can be entangled via the exchange of photons over long distances and, second, can store and process quantum information encoded in registers of qubits.



In this talk I will present our realization of a quantum network node based on a register of trapped calcium ions interfaced with photons via a high finesse optical cavity. The node combines capabilities of high-efficient single-photon emitter with local deterministic quantum logic and information storage. I will then present results of proof of principle experiments, enabled by those capabilities. These experiments include demonstrations of: (i) entanglement between two nodes placed in different buildings [2], (ii) quantum repeater node operating over a 50km long fiber channel [3], and (iii) multiplexed ion-photon entanglement and its distribution over 101 km of optical fiber (4). The talk will be concluded with the most recent results, prospects and limitations of our platform.



[1] H. J. Kimble, The quantum internet, Nature (London) 453 (2008)

[2] V. Krutyanskiy, M. Galli, et el., Entanglement of Trapped-Ion Qubits Separated by 230 Meters, Phys. Rev. Lett. 130 (2023).

[3] V Krutyanskiy, M Canteri, M Meraner, J Bate, V Krcmarsky, J Schupp, N. Sangouard, B. Lanyon, Telecom-wavelength quantum repeater node based on a trapped-ion processor Phys. Rev. Lett. 130 (2023)

[4] V Krutyanskiy, M Canteri, M Meraner, V Krcmarsky, BP Lanyon, Multimode ion-photon entanglement over 101 kilometers of optical fiber, arXiv preprint arXiv:2308.08891 (2023)