We construct a theory of continuous-variable entanglement-assisted quantum
error correction. We present an example of a continuous-variable
entanglement-assisted code that corrects for an arbitrary single-mode error. We
also show how to implement encoding circuits using passive optical devices,
homodyne measurements, feedforward classical communication, conditional
displacements, and off-line squeezers.Comment: 8 pages, 1 figure, major expansion of paper with detailed exampl