Quantum no-stretching: A geometrical interpretation of the no-cloning theorem

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• 作者：Giacomo M. D'Ariano ; Paolo Perinotti
• 关键词：Quantum information ; No-go theorems ; Spin ; Spatial rotations
• 刊名：Physics Letters A
• 出版年：2009
• 出版时间：29 June 2009
• 年：2009
• 卷：373
• 期：29
• 页码：2416-2419
• 全文大小：208 K

文摘

We consider the ideal situation in which a space rotation is transferred from a quantum spin j to a quantum spin l≠j. Quantum-information theoretical considerations lead to the conclusion that such operation is possible only for lj. For l>j the optimal stretching transformation is derived. We show that for qubits the present no-stretching theorem is equivalent to the usual no-cloning theorem.