CONTINUOUS ERROR-CORRECTION

We propose a new approach to study the evolution of a quantum state th at is encoded in a system which is continuously subjected to the opera tions required to implement a quantum error-correcting code. In the li mit of continuous error correction we introduce a Markovian master equ ation that includes the effects of: (a) Hamiltonian evolution; (b) err ors caused by the interaction with an environment; and (c) error-corre cting operations. The master equation is formally presented for all st abilizer codes and its solution is analysed for the simplest such code .