Rate Loss in Quantum Channels with Classical State and Applications for Quantum Broadcast Channels
Provides theoretical insights into rate loss and coding strategies for quantum communication channels, relevant to quantum information theory researchers.
The paper identifies a rate loss in classical-quantum channels due to missing receiver channel state information and proves that coset-code-based strategies outperform IID-code-based strategies for certain 3-user broadcast channels.
We consider the problem of \textit{rate loss} - a strict penalty suffered in achievable rates due to the lack of channel state information at the receiver (Rx) of a classical-quantum (CQ) channel. First, we identify non-commutative CQ channels and analytically prove a rate loss. Building on this, we next prove that coset-code-based strategies can strictly outperform conventional unstructured IID-code-based strategies for non-commutative 3-user CQ broadcast channels.