Optically-Heralded Entanglement of Superconducting Systems in Quantum Networks

The typical approach to communication between two superconducting quantum computers is to transduce into the optical regime and then back into the microwave regime. However, direct microwave-to-optical transduction has low fidelity due to the low microwave-optical coupling rates and added noise; these problems compound in the consecutive egress and ingress transduction steps. We break this rate-fidelity trade-off by heralding end-to-end entanglement with one detected photon and teleportation. In contrast to cascaded direct transduction, our scheme absorbs the low optical-microwave coupling efficiency into the entanglement heralding step. Our approach unifies and simplifies entanglement generation between superconducting devices and other physical modalities in quantum networks.