Universal and phase covariant superbroadcasting for mixed qubit states

Abstract

We describe a general framework to study covariant symmetric broadcasting maps for mixed qubit states. We explicitly derive the optimal N to M superbroadcasting maps, achieving optimal purification of the single-site output copy, in both the universal and the phase covariant cases. We also study the bipartite entanglement properties of the superbroadcast states.

19 pages, 8 figures, strictly related to quant-ph/0506251 and quant-ph/0510155

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Cited by in corpus (9)

• Quantum Cloning Machines and the Applications
• Optimal compression for identically prepared qubit states
• Cooperative spontaneous emission from indistinguishable atoms in arbitrary motional quantum states
• Information-theoretic limitations on approximate quantum cloning and broadcasting
• Phase-covariant cloning of coherent states
• Dispensing of quantum information beyond no-broadcasting theorem -- is it possible to broadcast anything genuinely quantum?
• Superbroadcasting and classical information
• Virtual phase-covariant quantum broadcasting for qubits
• Superbroadcasting of harmonic oscillators mixed states