Frequency-bin-encoded microwave photons with quantum error detection for distributed quantum computing

Quantum communication between distant processors is essential for scalable distributed quantum computing. In superconducting circuits, this requires transferring quantum information via propagating microwave photons, but photon loss during transmission remains a major challenge. In our recent work [1], we demonstrate a heralded frequency-bin encoding scheme that enables photon loss detection in a superconducting platform. We deterministically generate frequency-bin-encoded microwave photons by simultaneously emitting a qubit's quantum information into two frequency modes, achieving a process fidelity of 90.4%. The encoded modes allow the receiver to detect photon loss, enabling quantum error detection in the communication channel. Our results establish a foundation for reliable microwave-photon emission in distributed architectures. Future work will focus on completing the quantum link by implementing both emission and reabsorption, enabling high-fidelity state transfer between superconducting quantum nodes.

[1] Jiaying Yang et al., Phys. Rev. Lett. 134, 240803 (2025).