The Gottesman-Kitaev-Preskill (GKP) code encodes a logical qubit into a
bosonic system with resilience against single-photon loss, the predominant
error in most bosonic systems. Here we present experimental results
demonstrating quantum error correction of GKP states based on reservoir
engineering of a superconducting device. Error correction is made autonomous
through an unconditional reset of an auxiliary transmon qubit. The lifetime of
the logical qubit is shown to be increased from quantum error correction,
therefore reaching the point at which more errors are corrected than generated.Comment: 6 pages, 3 figures + 26 pages, 12 figure