Entanglement thresholds for displaying the quantum nature of teleportation

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• 作者：Luis Roa^a ; ^{lroa@udec.cl" class="auth_mail" title="E-mail the corresponding author} ; Robinson Gó ; mez^a ; ^b ; Ariana Muñ ; oz^a ; ^b ; Gautam Rai^c ; Matthias Hecker^d
• 关键词：Teleportation ; Average fidelity ; Entanglement threshold ; XX-state ; Noisy channel
• 刊名：Annals of Physics
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：371
• 期：Complete
• 页码：228-238
• 全文大小：418 K

文摘

A protocol for transferring an unknown single qubit state evidences quantum features when the average fidelity of the outcomes is, in principle, greater than 2/3$2/3$. We propose to use the probabilistic and unambiguous state extraction scheme   as a mechanism to redistribute the fidelity in the outcome of the standard teleportation when the process is performed with an X$X$-state as a noisy quantum channel. We show that the entanglement of the channel is necessary but not sufficient in order for the average fidelity 68081c4360784ec690d6dd543" title="Click to view the MathML source">f_X$f_X$ to display quantum features, i.e., we find a threshold C_X$C_X$ for the concurrence of the channel. On the other hand, if the mechanism for redistributing fidelity is successful then we find a filterable outcome with average fidelity f_X,0$f_{X,0}$ that can be greater than 68081c4360784ec690d6dd543" title="Click to view the MathML source">f_X$f_X$. In addition, we find the threshold concurrence of the channel C_X,0$C_{X,0}$ in order for the average fidelity f_X,0$f_{X,0}$ to display quantum features and surprisingly, the threshold concurrence C_X,0$C_{X,0}$ can be less than C_X$C_X$. Even more, we find some special cases for which the threshold values become zero.