Quantum Information Transmission Over a Partially Degradable Channel

We investigate a quantum coding for quantum communication over a partially degradable (PD) quantum channel. For a PD channel, the degraded environment state can be expressed from the channel output state up to a degrading map. PD channels can be restricted to the set of optical channels, which allows for the parties to exploit the benefits in experimental quantum communications. We show that for a PD channel, the partial degradability property leads to higher quantum data rates in comparison with those of a degradable channel. The PD property is particularly convenient for quantum communications and allows one to implement the experimental quantum protocols with higher performance. We define a coding scheme for PD channels and give the achievable rates of quantum communication.