Non-classical microwave-optical photon pair generation with a chip-scale transducer

TL;DR

This paper demonstrates non-classical photon pair generation linking optical and microwave frequencies using a chip-scale transducer, advancing quantum network integration for superconducting quantum processors.

Contribution

It reports the first observation of non-classical correlations between optical photons and microwave photons via a chip-scale piezo-optomechanical transducer.

Findings

Verified non-classical correlations through anti-bunching measurements.

Achieved photon pair generation compatible with superconducting quantum processors.

Demonstrated a key component for optical quantum networks of microwave qubits.

Abstract

Modern computing and communication technologies such as supercomputers and the internet are based on optically connected networks of microwave frequency information processors. In recent years, an analogous architecture has emerged for quantum networks with optically distributed entanglement between remote superconducting quantum processors, a leading platform for quantum computing. Here we report an important milestone towards such networks by observing non-classical correlations between photons in an optical link and a superconducting electrical circuit. We generate such states of light through a spontaneous parametric down-conversion (SPDC) process in a chip-scale piezo-optomechanical transducer. The non-classical nature of the emitted light is verified by observing anti-bunching in the microwave state conditioned on detection of an optical photon. Such a transducer can be readily connected to a superconducting quantum processor, and serve as a key building block for optical quantum networks of microwave frequency qubits.