The quantum capacity is properly defined without encodings

Abstract

We show that no source encoding is needed in the definition of the capacity of a quantum channel for carrying quantum information. This allows us to use the coherent information maximized over all sources and and block sizes, but not encodings, to bound the quantum capacity. We perform an explicit calculation of this maximum coherent information for the quantum erasure channel and apply the bound in order find the erasure channel's capacity without relying on an unproven assumption as in an earlier paper.

19 pages revtex with two eps figures. Submitted to Phys. Rev. A. Replaced with revised and simplified version, and improved references, etc. Why can't the last line of the comments field end with a period using this web submission form?

References in corpus (4)

• Optimal Universal and State-Dependent Quantum Cloning
• Information transmission through a noisy quantum channel
• Capacities of Quantum Erasure Channels
• Entropic bounds on coding for noisy quantum channels

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• Entanglement-Assisted Classical Capacity of Noisy Quantum Channels
• Quantum channels and memory effects
• A Survey on Quantum Channel Capacities
• Fundamentals of Quantum Information Theory
• The entanglement of purification
• Quantum Channels with Memory
• On Quantum Fidelities and Channel Capacities
• Entanglement required in achieving entanglement-assisted channel capacities
• Tema Con Variazioni: Quantum Channel Capacity
• Continuity of quantum channel capacities
• Unified approach to quantum capacities: towards quantum noisy coding theorem
• Broadband channel capacities
• The Minimum Distance Problem for Two-Way Entanglement Purification
• Optimal compression for mixed signal states
• Stochastic resonance for quantum channels
• Positivity, Discontinuity, Finite Resources and Nonzero Error for Arbitrarily Varying Quantum Channels
• Simple test for quantum channel capacity
• Entanglement-assisted capacity of a quantum channel and the reverse Shannon theorem
• Noise effects on One-Pauli Channels
• Quantum channel capacities - multiparty communication
• Information Rates Achievable with Algebraic Codes on Quantum Discrete Memoryless Channels
• Aspects of multistation quantum information broadcasting