An elementary quantum network of remote ⁸⁸Sr⁺ qubits

ORAL

Abstract

Remote entanglement is an essential resource for many quantum networking protocols. To create entangled states of two remote ⁸⁸Sr⁺ qubits, we first entangle each ion with the polarisation of spontaneously emitted 422 nm photons coupled into single-mode fibres, followed by entanglement swapping using linear optics. To minimise ion micromotion that would reduce photon mode overlap, we develop a simple technique for multi-dimensional stray field compensation without extra laser beams or spatially resolved imaging. We characterise the achieved photonic link performance, which (at 94% Bell state fidelity and an average rate of 182 s⁻¹ [1]) represents the state of the art in high-fidelity remote entanglement across all qubit platforms, and discuss recent progress towards networking applications such as quantum key distribution.

[1] PRL 124, 110501 (2020)

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Publication: L. J. Stephenson, D. P. Nadlinger, et al., "High-rate, high-fidelity entanglement of qubits across an elementary quantum network", Phys. Rev. Lett. 124, 110501 (2020)

Presenters

  • David Nadlinger

    • University of Oxford

Authors

  • David Nadlinger

    • University of Oxford

  • Bethan Nichol

    • University of Oxford

  • Peter Drmota

    • University of Oxford

  • Gabriel Araneda

    • University of Oxford

  • Dougal Main

    • University of Oxford
    • Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, U.K.

  • Raghavendra Srinivas

    • University of Oxford
    • University of Colorado, Boulder

  • David Lucas

    • University of Oxford
    • Department of Physics, University of Oxford

  • Christopher Ballance

    • Department of Physics, University of Oxford
    • University of Oxford