Error-Detected State Transfer and Entanglement in a Superconducting Quantum Network
Luke Burkhart, James D. Teoh, Yaxing Zhang, Christopher J. Axline, Luigi Frunzio, Michel Devoret, Liang Jiang, S. M. Girvin, Robert J. Schoelkopf · PRX Quantum · 2021
Microwave photons are used to wire up modular quantum processors, but mitigating the effects of loss between modules remains a crucial challenge.We use a low-loss bus resonator to couple bosonic qubits across a superconducting network with protocols made robust to photon loss in the bus.We transfer a multiphoton qubit and track loss events, improving the fidelity to the break-even point with respect to the best uncorrectable encoding.We also demonstrate a entanglement protocol using Hong-Ou-Mandel interference and error detection to prepare a two-photon Bell state with fidelity 94% and success probability 0.79, halving the error obtained with a single photon.This network link also presents new opportunities for resource-efficient direct gates between modules.