Strategies for Positive Partial Transpose (PPT) States in Quantum Metrologies with Noise |
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Authors: | Arunava Majumder Harshank Shrotriya Leong-Chuan Kwek |
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Institution: | 1.Indian Institute of Technology Kharagpur, Kharagpur 721302, India;2.Centre for Quantum Technologies, National University of Singapore, Singapore 117543, Singapore; (H.S.); (L.-C.K.);3.MajuLab, CNRS-UNS-NUS-NTU International Joint Research Unit, Singapore UMI 3654, Singapore;4.National Institute of Education, Nanyang Technological University, Singapore 637616, Singapore;5.Quantum Science and Engineering Center, Nanyang Technological University, Singapore 637616, Singapore |
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Abstract: | Quantum metrology overcomes standard precision limits and has the potential to play a key role in quantum sensing. Quantum mechanics, through the Heisenberg uncertainty principle, imposes limits on the precision of measurements. Conventional bounds to the measurement precision such as the shot noise limit are not as fundamental as the Heisenberg limits, and can be beaten with quantum strategies that employ ‘quantum tricks’ such as squeezing and entanglement. Bipartite entangled quantum states with a positive partial transpose (PPT), i.e., PPT entangled states, are usually considered to be too weakly entangled for applications. Since no pure entanglement can be distilled from them, they are also called bound entangled states. We provide strategies, using which multipartite quantum states that have a positive partial transpose with respect to all bi-partitions of the particles can still outperform separable states in linear interferometers. |
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Keywords: | PPT quantum metrology entanglement |
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