  A generalization of the stabilizer code construction presented by Gottesman
is described, which allows for the construction of quantum error-correcting
codes for continuous-variable systems. This formalism describes all
continuous-variable codes presented to date, and can be used to construct new
codes based on discrete-variable codes or classical codes. We use it to
describe the nine-mode code given by Lloyd and Slotine, and a five-mode code
described by Braunstein. In addition, we construct a new continuous-variable
code based an code of Gottesman which encodes three logical modes of
information into eight physical modes and corrects one error. This
generalization is a step toward an independent understanding of
continuous-variable quantum information and a theory of fault-tolerant quantum
information processing.
