  The smallest quantum code that can correct all one-qubit errors is based on
five qubits. We experimentally implemented the encoding, decoding and
error-correction quantum networks using nuclear magnetic resonance on a five
spin subsystem of labeled crotonic acid. The ability to correct each error was
verified by tomography of the process. The use of error-correction for
benchmarking quantum networks is discussed, and we infer that the fidelity
achieved in our experiment is sufficient for preserving entanglement.

Quantum Physics