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Cloning the entanglement of a pair of quantum bits

Louis-Philippe Lamoureux·Patrick Navez·Jaromir Fiurasek·Nicolas J. Cerf
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Abstract

It is shown that any quantum operation that perfectly clones the entanglement of all maximally-entangled qubit pairs cannot preserve separability. This ``entanglement no-cloning'' principle naturally suggests that some approximate cloning of entanglement is nevertheless allowed by quantum mechanics. We investigate a separability-preserving optimal cloning machine that duplicates all maximally-entangled states of two qubits, resulting in 0.285 bits of entanglement per clone, while a local cloning machine only yields 0.060 bits of entanglement per clone.

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Louis-Philippe Lamoureux, Patrick Navez, Jaromir Fiurasek, Nicolas J. Cerf. 2003-10-13. Cloning the entanglement of a pair of quantum bits. https://doi.org/10.1103/physreva.69.040301

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