  Quantum error correction protects the quantum state against noise and
decoherence in quantum communication and quantum computation, which enables one
to perform fault-torrent quantum information processing. We experimentally
demonstrate a quantum error correction scheme with a five-wave-packet code
against a single stochastic error, the original theoretical model of which is
firstly proposed by S. L. Braunstein and T. A. Walker. Five submodes of a
continuous variable cluster entangled state of light are used for five encoding
channels. Especially, in our encoding scheme the information of the input state
is only distributed on three of the five channels and thus any error appearing
in the remained two channels never affects the output state, i.e. the output
quantum state is immune from the error in the two channels. The stochastic
error on a single channel is corrected for both vacuum and squeezed input
states and the achieved fidelities of the output states are beyond the
corresponding classical limit.
