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Optimal asymmetric cloning machine on a great circle using no-signalling condition

Samir Kunkri·Md. Manirul Ali·Geetu Narang·Debasis Sarkar
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Abstract

Assuming the condition of no superluminal signalling, we got an upper bound on the quality of all asymmetric $ 1\to 2$ cloning machines, acting on qubits whose Bloch vectors lie on a great circle. Then we constructed an $ 1\to 2$ cloning machine, which asymmetrically clone all qubits corresponding to this great circle, and this machine matches with that upper bound, and hence this is optimal one.

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Samir Kunkri, Md. Manirul Ali, Geetu Narang, Debasis Sarkar. 2002-11-26. Optimal asymmetric cloning machine on a great circle using no-signalling condition. https://arxiv.org/abs/quant-ph/0211169

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