Coherent microwave single-photon source for a mechanically mediated electro-optic transducer

A low-noise, highly efficient transducer is essential for interfacing superconducting qubits over long distances. However, generating a high-coherence quantum state that matches the transducer’s narrow kHz bandwidth presents a significant challenge, as it requires a long pulse duration. In this talk, I will present our experimental efforts to build a coherent quantum source for our mechanically-mediated transducer. This single-photon source consists of two 3D cavities and a transmon qubit. The transmon provides the necessary nonlinearity for generating the single-photon state and acts as a four-wave mixing element to transfer the quantum state between the two cavities.