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arXiv · 2407.20943

Proposal for Superconducting Quantum Networks Using Multi-Octave Transduction to Lower Frequencies

Takuma Makihara·Wentao Jiang·Amir H. Safavi-Naeini
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Abstract

We propose networking superconducting quantum circuits by transducing their excitations (typically 4-8 GHz) to 100-500 MHz photons for transmission via cryogenic coaxial cables. Counter-intuitively, this frequency downconversion reduces noise and transmission losses. We introduce a multi-octave asymmetrically threaded SQUID circuit (MOATS) capable of the required efficient, high-rate transduction. For a 100-meter cable with $Q_i = 10^5$ at 10 mK, our approach achieves single-photon fidelities of 0.962 at 200 MHz versus 0.772 at 8 GHz, and triples the lower bound on quantum channel capacity. This method enables kilometer-scale quantum links while maintaining high fidelities, combining improved performance with the practical advantages of flexible, compact coaxial cables.

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Takuma Makihara, Wentao Jiang, Amir H. Safavi-Naeini. 2024-07-30. Proposal for Superconducting Quantum Networks Using Multi-Octave Transduction to Lower Frequencies. https://arxiv.org/abs/2407.20943

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