Quantum experiments with mechanical and optical excitations

Mechanical resonators have attracted significant attention for their potential use in quantum information processing tasks. Their unique ability to couple to a large variety of quantum systems and the freedom to design their properties makes them ideally suited as, for example, compact quantum memories or as transducers between the microwave and the optical domain.

Here, we would like to present experiments demonstrating the potential of such a mechanical system as a transducer between superconducting qubits and an optical fiber network. Our approach is based on an optomechanical crystal, with mechanical resonances in the Gigahertz regime which can be addressed optically from the conventional telecom band, while resonantly also coupling to a microwave resonator through a piezoelectric block. We show how these structures can be used to perform an optical measurement of the qubit state, as well as to coherently convert information between the two domains.