Microwave-to-Optical Quantum Transduction via Defect-Mediated Scattering in Diamond

TL;DR

This paper introduces a low-power microwave-to-optical quantum transducer using a single color center in diamond, enabling efficient, coherent conversion suitable for scalable quantum networks.

Contribution

It proposes a novel transducer design based on defect-mediated scattering in diamond, achieving strong coupling at extremely low pump powers.

Findings

Coherent conversion achieved at pump powers around 10 pW.

Remote entanglement generation at ~1 kHz with >0.9 fidelity.

Demonstrates a pathway for ultra-low-power quantum transducers.

Abstract

Scaling up superconducting quantum processors remains a central challenge for realizing fault-tolerant quantum computation. Although distributed architectures based on optical photons offer a promising route to scalability, they require an efficient microwave-to-optical quantum transducer that operates at cryogenic temperatures. Existing approaches typically rely on strong optical pumping, which induces undesirable heating and degrades single-photon coherence. Here, we propose a microwave-to-optical quantum transducer based on double-resonant scattering from a single color center embedded in a diamond optomechanical resonator. We show that strong coupling between the color center and the optical cavity enables coherent conversion at extremely low pump powers on the order of 10 pW. The proposed device enables remote entanglement generation on the order of 1 kHz with a fidelity exceeding 0.9, demonstrating a viable pathway toward ultra-low-power, high-efficiency quantum transducers based on individual solid-state defects for future distributed superconducting quantum networks.