  Quantum information protocols are inevitably affected by decoherence which is
associated with the leakage of quantum information into an environment. In this
paper we address the possibility of recovering the quantum information from an
environmental measurement. We investigate continuous variable quantum
information, and we propose a simple environmental measurement that under
certain circumstances fully restores the quantum information of the signal
state although the state is not reconstructed with unit fidelity. We implement
the protocol for which information is encoded into conjugate quadratures of
coherent states of light and the noise added under the decoherence process is
of Gaussian nature. The correction protocol is tested using both a
deterministic as well as a probabilistic strategy. The potential use of the
protocol in a continuous variable quantum key distribution scheme as a means to
combat excess noise is also investigated.
