| Scheme to measure the expectation value of a physical quantity in weak coupling regime |
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| 作者姓名： | 张杰 吴春旺 谢艺 吴伟 陈平形 |
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| 作者单位： | Department of Physics;Interdisciplinary Center for Quantum Information |
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| 基金项目： | Project supported by the National Natural Science Foundation of China(Grant Nos.12004430 and 61632021);the National Basic Research Program of China(Grant No.2016YFA0301903). |
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| 摘 要： | In quantum mechanics, the expectation value of an operator can be measured by using the projective measurement, ifthe coupling between the measured system and pointer is strong enough. However in the weak coupling regime, the pointercan not show all the eigenvalue of the physical quantity directly due to the overlapping among the pointer states, whichmakes the measurement of the expectation value difficult. In this paper, we propose an expectation value measurementmethod in the weak coupling regime inspired by the weak measurement scheme. Compared to the projective measurement,our scheme has two obvious advantages. Experimentally we use the internal state and motional state of a single trapped40Ca+ to establish the measurement scheme and realize the proof of principle demonstration of the scheme.
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| 关 键 词： | weak measurement expectation value trapped ions |
Scheme to measure the expectation value of a physical quantity in weak coupling regime |
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| Jie Zhang,Chun-Wang Wu,Yi Xie,Wei Wu,Ping-Xing Chen.Scheme to measure the expectation value of a physical quantity in weak coupling regime[J].Chinese Physics B,2021(3). |
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| Authors: | Jie Zhang Chun-Wang Wu Yi Xie Wei Wu Ping-Xing Chen |
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| Institution: | (Department of Physics,College of Liberal Arts and Sciences,National University of Defense Technology,Changsha 410073,China;Interdisciplinary Center for Quantum Information,National University of Defense Technology,Changsha 410073,China) |
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| Abstract: | In quantum mechanics, the expectation value of an operator can be measured by using the projective measurement, if the coupling between the measured system and pointer is strong enough. However in the weak coupling regime, the pointer can not show all the eigenvalue of the physical quantity directly due to the overlapping among the pointer states, which makes the measurement of the expectation value difficult. In this paper, we propose an expectation value measurement method in the weak coupling regime inspired by the weak measurement scheme. Compared to the projective measurement,our scheme has two obvious advantages. Experimentally we use the internal state and motional state of a single trapped ~(40)Ca~+ to establish the measurement scheme and realize the proof of principle demonstration of the scheme. |
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