Partially Coherent Direct Sum Channels

Abstract

We introduce Partially Coherent Direct Sum (PCDS) quantum channels, as a generalization of the already known Direct Sum quantum channels. We derive necessary and sufficient conditions to identify the subset of those maps which are degradable, and provide a simplified expression for their quantum capacities. Interestingly, the special structure of PCDS allows us to extend the computation of the quantum capacity formula also for quantum channels which are explicitly not degradable (nor antidegradable). We show instances of applications of the results to dephasing channels, amplitude damping channels and combinations of the two.

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Cited by in corpus (5)

• Quantum capacity analysis of multi-level amplitude damping channels
• Resonant Multilevel Amplitude Damping Channels
• The noisy Werner-Holevo channel and its properties
• Additivity of quantum capacities in simple non-degradable quantum channels
• Exact Quantum Capacity of Decohering Channels in Arbitrary Dimensions