Browsing by Subject "joint measurement"

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    Joint measurement of multiple noncommuting parameters
    (APS, 2018-05) Li, Jiamin; Liu, Yuhong; Cui, Liang; Huo, Nan; Assad, Syed M.; Li, Xiaoying; Ou, Z. Y.; Physics, School of Science
    Although quantum metrology allows us to make precision measurements beyond the standard quantum limit, it mostly works on the measurement of only one observable due to the Heisenberg uncertainty relation on the measurement precision of noncommuting observables for one system. In this paper, we study the schemes of joint measurement of multiple observables which do not commute with each other using the quantum entanglement between two systems. We focus on analyzing the performance of a SU(1,1) nonlinear interferometer on fulfilling the task of joint measurement. The results show that the information encoded in multiple noncommuting observables on an optical field can be simultaneously measured with a signal-to-noise ratio higher than the standard quantum limit, and the ultimate limit of each observable is still the Heisenberg limit. Moreover, we find a resource conservation rule for the joint measurement.
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    Quantum enhanced joint measurement of two conjugate observables with an SU(1, 1) interferometer
    (IEEE, 2017) Liu, Yuhong; Li, Jiamin; Huo, Nan; Li, Xiaoying; Ou, Z. Y.; Physics, School of Science
    We jointly measure the phase and amplitude modulation of an optical field with the newly developed SU(1,1) interferometer. We simultaneously achieve a signal-to-noise ratio improvement of 1.1 and 1 dB over the standard quantum limit in amplitude and phase measurement.