  We propose a new approach to study the evolution of a quantum state that is
encoded in a system which is continuously subject to the operations required to
implement a quantum error correcting code. In the limit of continuous error
correction we introduce a Markovian master equation that includes the effects
of: a) Hamiltonian evolution, b) errors caused by the interaction with an
environment and c) error-correcting operations. The master equation is formally
presented for all stabilizer codes and its solution is analyzed for the
simplest such code.
