  Heralding techniques are useful in quantum communication to circumvent losses
without resorting to error correction schemes or quantum repeaters. Such
techniques are realized, for example, by monitoring for photon loss at the
receiving end of the quantum link while not disturbing the transmitted quantum
state. We describe and experimentally benchmark a scheme that incorporates
error detection in a quantum channel connecting two transmon qubits using
traveling microwave photons. This is achieved by encoding the quantum
information as a time-bin superposition of a single photon, which
simultaneously realizes high communication rates and high fidelities. The
presented scheme is straightforward to implement in circuit QED and is fully
microwave-controlled, making it an interesting candidate for future modular
quantum computing architectures.
