QUANTUM DATA PROCESSING AND ERROR CORRECTION
This paper investigates properties of noisy quantum information channels. We define a quantity called coherent information, which measures the amount of quantum information conveyed in the noisy channel. This quantity can never be increased by quantum information processing, and it yields a simple necessary and sufficient condition for the existence of perfect quantum error correction.
Schumacher, Benjamin and Nielsen, M., "QUANTUM DATA PROCESSING AND ERROR CORRECTION" (1996). Physical Review A 54(4): 2629-2635. Faculty Publications. Paper 274.
Physical Review A