An Infinite Sequence of Additive Channels: the Classical Capacity of Cloning Channels

Understand

We introduce an infinite sequence of quantum channels for which the Holevo capacity is additive.

• The channel series is closely related to the quantum channels arising from universal quantum cloning machines.
• The additivity proof is motivated by a special property the studied channels enjoy: the property of conjugate degradability.
• As a consequence of the announced proof, we also provide an easy way of proving the additivity of the Holevo capacity for the original Unruh channel for which the quantum capacity is already known.