TABLE I. Hardware-efficiency metrics for the GKP code [17], the χ (2) PCC, the χ (2) EECC, and the χ (2) BC when all four encode a single logical qubit. GEE: Gaussian embedded error. PNR: photon number-resolving detection. PNP: photon-number parity measurement. GPNP: generalized photon-number parity measurement. CM: channel monitoring.