| Quantum information science is a new subject recently developed by combining quantum mechanics,classical information technology and computer science.Comparing with traditional information science,quantum information has obvious advantages in the arithmetic speed,the capacity of information,the detection precision,information security and so on,and it has broad applications.The uncertainty relation is one of the most fundamental principles in quantum mechanics.With the development of quantum mechanics,there are two kinds of uncertainty relations.One is the preparation uncertainty relation,which reflects the minimal dispersion of two quantum observables before measurement and it is always valid.The other is the measurement uncertainty relation,which studies the extent to which the accuracy of a position measurement is related to the disturbance of the particle‘s momentum.In quantum information science,the processing of information encoding,transmitting and computing are based on the quantum states and the detection of quantum states.So the quantum measurement plays an important role in quantum information science.But the precision of measurement is limited by the error-disturbance uncertainty relation.So,the error-disturbance uncertainty relation plays an important role in the developing quantum information science.Quantum steering is an intermediate type of quantum correlation between entanglement and Bell nonlocality.It not only helps to understand the fundamental physics,but also is an important quantum resource.Different from quantum entanglement,the asymmetric property is the internal character of quantum steering.In certain cases,quantum steering could be one-way(only one party can steer the other party's quantum state),which is the character that quantum entanglement do not have.Due to this intriguing feature,quantum steering has potential applications in one-sided device independent quantum key distribution,quantum secret sharing and secure quantum teleportation et al.In practical application,one of the obstacles in quantum information is the decoherence caused by the inevitable loss and noise in quantum channels.Realization of distillation of quantum steering can fight against the effect of decoherence to quantum steering.It has been shown that noiseless linear amplification is an effective method to reduce the decoherence effect induced by loss.So,we realize distillation of Gaussian quantum steering using the measurement-based noiseless linear amplification,which provides technical reference for more complicated quantum information technology with quantum steering.The main completed works are as following:1.We present the first experimental test of the continuous variable error–disturbance uncertainty relation using two incompatible variables,amplitude and phase quadratures of an optical mode,of a Gaussian Einstein–Podolsky–Rosen(EPR)entangled state.By choosing the suitable observable and based on quantum correlation between entangled optical field,we experimentally measure the uncertainty of error and disturbance of amplitude and phase quadratures of one of EPR entangled state.Experimental results show that the Heisenberg‘s error–disturbance uncertainty relation with continuous variables can be violated in some cases,while Ozawa‘s and Branciard‘s error-disturbance uncertainty relations are valid.Especially,we experimentally test the error–tradeoff relation in the case of zero error by using Gaussian EPR entangled state.This work is published in npj Quantum Information,2019,5,68.2.We realize the simultaneously measurement of amplitude and phase quadratures of an optical field using heterodyne detection system,and test the error-disturbance uncertainty relations with three different Gaussian states,i.e.,coherent state,squeezed state and thermal state as signal mode.The experimental results show that the Heisenberg‘s error-disturbance uncertainty relation with continuous variables is violated,while Ozawa‘s and Branciard‘s relations are validated,for different quantum states.This work is published in Photonics Research,2019,7,11.3.We experimentally demonstrate the distillation of Gaussian EPR steering in lossy and noisy channels by using measurement-based noiseless linear amplification.One optical field of a two-mode squeezed state is transmitted to Bob through a lossy or noisy channel,while Alice keeps the other optical field of the two-mode squeezed state.Alice and Bob measure the information of their own state with homodyne and heterodyne detection systems,respectively.After that,Alice and Bob select the experimental data using a filter function and realize measurement-based noiseless linear amplification.The experimental results show that the distilled EPR steering is increased for both directions and the two-way steering is recovered from one-way steering in certain region of loss by the measurement-based noiseless linear amplification.We also show that the distilled EPR steering allows to extracted secret key in one-sided device-independent quantum key distribution.This work is submitted to PRL.The creative works are as following:1.We designed the scheme for verification of error-disturbance uncertainty relation with continuous variables based on EPR entangled state,and realized the first experimental test of error-disturbance uncertainty relation with continuous variables.2.We designed the scheme for verification of error-disturbance uncertainty relation with continuous variables using heterodyne detection system,and realized the experimental test of error-disturbance uncertainty relation with continuous variables using coherent,squeezed and thermal states as input states respectively.3.We experimentally realized the distillation of Gaussian EPR steering in lossy and noisy channels by using measurement-based noiseless linear amplification. |
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