EIT-based quantum memory using entangled photons from a trapped ion*

Leveraging the complementary strengths of different types of qubits in quantum memories, hybrid quantum networking promises an advantage over single-species quantum networks for practical implementation of distributed tasks such as quantum computing, simulation, and data security [1-4]. Critical to a proposed method [5] improving entanglement generation rates in trapped-ion quantum networks are the ion’s ability to generate entanglement on-demand with single-photons, neutral-atoms’ ability to manipulate single-photons, and a photon’s ability to herald entanglement across long distances [6-7]. Here, we report on storing a quantum frequency converted (QFC) barium ion-entangled flying qubit in a rubidium quantum memory using electromagnetic induced transparency (EIT). Additionally, we present transmission characterization [8] of a multi-site, inter-city network, useful for communicating our frequency-converted, polarization-entangled flying qubit from the ion in the O-band. This work enables synthesizing hybrid components over a quantum network.

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[8] W. McKenzie et al., Appl. Phys. Lett. 125, 164004 (2024)