arXiv subjects

Nan Huo

Publications and source records attributed to Nan Huo.

23 records · Page 2Linked to original sources

arXiv2020

Direct temporal mode measurement for the characterization of temporally multiplexed high dimensional quantum entanglement in continuous variables

Field-orthogonal temporal mode analysis of optical fields is recently developed for a new framework of quantum information science. But so far, the exact profiles of the temporal modes are not known, which makes it difficult to achieve mode selection and de-multiplexing. Here, we report a novel method that measures directly the exact form of the temporal modes. This in turn enables us to make mode-orthogonal homodyne detection with mode-matched local oscillators. We apply the method to a pulse-pumped, specially engineered fiber parametric amplifier and demonstrate temporally multiplexed multi-dimensional quantum entanglement of continuous variables in telecom wavelength. The temporal mode characterization technique can be generalized to other pulse-excited systems to find their eigen modes for multiplexing in temporal domain.

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arXiv2019

Measuring the continuous variable quantum entanglement with a parametric amplifier assisted homodyne detection

Traditional method for measuring continuous-variable quantum entanglement relies on balanced homodyne detections, which are sensitive to vacuum quantum noise coupled in through losses resulted from many factors such as detector's quantum efficiency and mode mismatching between detected field and local oscillator. In this paper, we propose and analyze a new measurement method, which is realized by assisting the balanced homodyne detections with a high gain phase sensitive parametric amplifier. The employment of the high gain parametric amplifier helps to tackle the vacuum quantum noise originated from detection losses. Moreover, because the high gain parametric amplifier can couple two fields of different types in a phase sensitive manner, the proposed scheme can be used to reveal quantum entanglement between two fields of different types by using only one balanced homodyne detection. Furthermore, detailed analysis shows that in the multi-mode case, the proposed scheme is also advantageous over the traditional method. Such a new measurement method should find wide applications in quantum information and quantum metrology involving measurement of continuous variables.

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arXiv2018

Optimum quantum resource distribution for phase measurement and quantum information tapping in a dual-beam SU(1,1) interferometer

Quantum entanglement is a resource in quantum metrology that can be distributed to two orthogonal physical quantities for the enhancement of their joint measurement sensitivity, as demonstrated in quantum dense metrology. On the other hand, we can also devote all the quantum resource to phase measurement only for optimum measurement sensitivity. Here, we experimentally implement a dual-beam scheme in an SU(1,1) interferometer for the optimum phase measurement sensitivity. We demonstrate a 3.9-dB improvement in signal-to-noise ratio over the optimum classical method and this is 3-dB better than the traditional single-beam scheme. Furthermore, such a scheme also realizes a quantum optical tap of quantum entangled fields and has the full advantages of an SU(1,1) interferometer for practical applications in quantum metrology and quantum information.

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arXiv2018

Joint Multi-Parameter Measurement

Although quantum metrology allows us to make precision measurement beyond the standard quantum limit, it mostly works on the measurement of only one observable due to Heisenberg uncertainty relation on the measurement precision of non-commuting observables for one system. In this paper, we study the schemes of joint measurement of multiple observables which do not commute with each other by using the quantum entanglement between two systems. We focus on analyzing the performance of newly developed SU(1,1) interferometer on fulfilling the task of joint measurement. The results show that the information encoded in multiple non-commuting 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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arXiv2017

Quantum enhanced joint measurement of multiple non-commuting observables with SU(1,1) interferometer

Heisenberg uncertainty relation in quantum mechanics sets the limit on the measurement precision of non-commuting observables, which prevents us from measuring them accurately at the same time. In some applications, however, the information are embedded in two or more non-commuting observables. On the other hand, quantum entanglement allows us to infer through Einstein-Podolsky-Rosen correlations two conjugate observables with precision better than what is allowed by Heisenberg uncertainty relation. With the help of the newly developed SU(1,1) interferometer, we implement a scheme to measure jointly information encoded in multiple non-commuting observables of an optical field with a signal-to-noise ratio improvement of about 20 % over the standard quantum limit on all measured quantities simultaneously. This scheme can be generalized to the joint measurement of information in arbitrary number of non-commuting observables.

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