Lower limits of spin detection efficiency for two-parameter two-qubit (TPTQ) states with non-ideal ferromagnetic detectors

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• 作者：Nayereh Majd ; Zahra Ghasemi
• 关键词：Two ; parameter two ; qubit state ; Bell’s inequality ; CHSH inequality ; Non ; ideal ferromagnetic detector ; Entanglement witness ; Spin polarization ; Spin detector efficiency
• 刊名：Quantum Information Processing
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：15
• 期：10
• 页码：4137-4157
• 全文大小：1,421 KB
• 刊物类别：Physics and Astronomy
• 刊物主题：Physics
  Physics
  Mathematics
  Engineering, general
  Computer Science, general
  Characterization and Evaluation Materials
  
• 出版者：Springer Netherlands
• ISSN：1573-1332
• 卷排序：15

文摘

We have investigated a TPTQ state as an input state of a non-ideal ferromagnetic detectors. Minimal spin polarization required to demonstrate spin entanglement according to entanglement witness and CHSH inequality with respect to (w.r.t.) their two free parameters have been found, and we have numerically shown that the entanglement witness is less stringent than the direct tests of Bell’s inequality in the form of CHSH in the entangled limits of its free parameters. In addition, the lower limits of spin detection efficiency fulfilling secure cryptographic key against eavesdropping have been derived. Finally, we have considered TPTQ state as an output of spin decoherence channel and the region of ballistic transmission time w.r.t. spin relaxation time and spin dephasing time has been found.