A detailed study of some simple forms which have a given special structure have been solved, in this paper, we research the extension of this kind of special structure problems.
We study a system consisting of two identical non-interacting single-mode cavity fields coupled to a common vacuum environment and provide general, explicit, and exact solutions to its master equation by means of the ...We study a system consisting of two identical non-interacting single-mode cavity fields coupled to a common vacuum environment and provide general, explicit, and exact solutions to its master equation by means of the characteristic function method. We analyze the entanglement dynamics of two-mode squeezed thermal state in this model and show that its entanglement dynamics is strongly determined by the two-mode squeezing parameter and the purity. In particular, we find that two-mode squeezed thermal state with the squeezing parameter r ≤ -（1/2） In √u is extremely fragile and almost does not survive in a common vacuum environment. We investigate the time evolution of nonlocality for two-mode squeezed thermal state in such an environment. It is found that the evolved state loses its nonlocality in the beginning of the evolution, but after a time, the revival of nonlocality can occur.展开更多
We present a controlled secure quantum communication protocol using non-maximally （pure） entangled W states first, and then discuss the basic requirements for a real quantum communication. We show that the authorize...We present a controlled secure quantum communication protocol using non-maximally （pure） entangled W states first, and then discuss the basic requirements for a real quantum communication. We show that the authorized two users can exchange their secret messages with the help of the controller after purifying the non-maximally entangled states quantum channel unconditionally securely and simultaneously. Our quantum communication protocol seems even more feasible within present technologies.展开更多
We introduce the three-mode entangled state and set up an experiment to generate it. Then we discuss the three-mode squeezing operator squeezed ｜p, X2, X3〉→μ^-3/2｜p/μ, X2/μ, X3/μ） and the optical implement to...We introduce the three-mode entangled state and set up an experiment to generate it. Then we discuss the three-mode squeezing operator squeezed ｜p, X2, X3〉→μ^-3/2｜p/μ, X2/μ, X3/μ） and the optical implement to realize such a squeezed state. We also reveal that c-number .asymmetric shrink transform in the three-mode entangled state, i.e. ｜p, X2,X3）→μ^-1/2｜p/μ, X2,X3）, maps onto a kind of one-sided three-mode squeezing operator {iλ （∑i^3=1 Pi） （∑i^3=1 Qi） -λ/2}. Using the technique of integration within an ordered product （IWOP） of operators, we derive their normally ordered forms and construct the corresponding squeezed states.展开更多
State estimation of biological process variables directly influences the performance of on-line monitoring and op- timal control for fermentation process. A novel nonlinear state estimation method for fermentation pro...State estimation of biological process variables directly influences the performance of on-line monitoring and op- timal control for fermentation process. A novel nonlinear state estimation method for fermentation process is proposed using cubature Kalman filter （CKF） to incorporate delayed measurements. The square-root version of CI（F （SCKF） algorithm is given and the system with delayed measurements is described. On this basis, the sample-state augmentation method for the SCKF algorithm is provided and the implementation of the proposed algorithm is constructed. Then a nonlinear state space model for fermentation process is established and the SCKF algorithm incorporating delayed measurements based on fermentation process model is presented to implement the nonlinear state estimation. Finally, the proposed nonlinear state estimation methodology is applied to the state estimation for penicillin and industrial yeast fermentation processes. The simulation results show that the on-fine state estimation for fermentation process can be achieved by the proposed method with higher esti- mation accuracy and better stability.展开更多
Nonlinear quantum metrology may exhibit better precision scalings. For example, the uncertainty of an estimated phase may scale as △φ∝ 1/N2 under quadratic phase accumulation, which is 1/N times smal-ler than the l...Nonlinear quantum metrology may exhibit better precision scalings. For example, the uncertainty of an estimated phase may scale as △φ∝ 1/N2 under quadratic phase accumulation, which is 1/N times smal-ler than the linear counterpart, where N is probe number. Here, we experimentally demonstrate the non-linear quantum metrology by using a spin-I（I 〉 1/2） nuclear magnetic resonance （NMR） ensemble that can be mapped into a system ofN = 2I spin-1/2 particles and the quadratic interaction can be utilized for the quadratic phase accumulation. Our experimental results show that the phase uncertainty can scale as △φ∝1/（N2-1） by optimizing the input states, when N is an odd number. In addition, the interferomet-tic measurement with quadratic interaction provides a new way for estimating the quadrupolar coupling strength in an NMR system. Our system may be further extended to exotic nonlinear quantum metrology with higher order many-body interactions.展开更多
In this paper, we show that a(2, 3) discrete variable threshold quantum secret sharing scheme of secure direct communication can be achieved based on recurrence using the same devices as in BB84. The scheme is devised...In this paper, we show that a(2, 3) discrete variable threshold quantum secret sharing scheme of secure direct communication can be achieved based on recurrence using the same devices as in BB84. The scheme is devised by first placing the shares of smaller secret pieces into the shares of the largest secret piece, converting the shares of the largest secret piece into corresponding quantum state sequences, inserting nonorthogonal state particles into the quantum state sequences with the purpose of detecting eavesdropping, and finally sending the new quantum state sequences to the three participants respectively. Consequently, every particle can on average carry up to 1.5-bit messages due to the use of recurrence. The control codes are randomly prepared using the way to generate fountain codes with pre-shared source codes between Alice and Bob, making three participants can detect eavesdropping by themselves without sending classical messages to Alice. Due to the flexible encoding, our scheme is also dynamic, which means that it allows the participants to join and leave freely.展开更多
In this paper, we propose a very simple scheme to probe the quantum and classical correlation including quantum entanglement of Bell diagonal state. In the probing process, the correlation of Bell diagonal state, even...In this paper, we propose a very simple scheme to probe the quantum and classical correlation including quantum entanglement of Bell diagonal state. In the probing process, the correlation of Bell diagonal state, even the state itself, is not disturbed, which means a non-destructive probing. In addition, our scheme can be performed even though the two qubits of the Bell diagonal state are separate in space.展开更多
Despite the intense research efforts directed to electrocatalytic nitrogen reduction reaction(eNRR),the NH_(3) yield and selectivity are still not up to the standard of practical application.Here,high-entropy perovski...Despite the intense research efforts directed to electrocatalytic nitrogen reduction reaction(eNRR),the NH_(3) yield and selectivity are still not up to the standard of practical application.Here,high-entropy perovskite oxides with composition Bax(FeCoNiZrY)_(0.2)O_(3−δ)(Bx(FCNZY)_(0.2)(x=0.9,1)are reported as eNRR catalysts.The eNRR activity of high-entropy perovskite oxide is enhanced by changing the nonstoichiometric metal elements at the A-site,thus generating additional oxygen vacancies.The NH_(3) yield and Faraday efficiency for B_(0.9)(FCNZY)_(0.2) are 1.51 and 1.95 times higher than those for B(FCNZY)_(0.2),respectively.The d-band center theory is used to theoretically predict the catalytically active center at the B-site,and as a result,nickel was identified as the catalytic site.The free energy values of the intermediate states in the optimal distal pathway show that the third protonation step(*NNH_(2)→*NNH_(3))is the rate-determining step and that the increase in oxygen vacancies in the high-entropy perovskite contributes to nitrogen adsorption and reduction.This work provides a framework for applying high-entropy structures with active site diversity for electrocatalytic nitrogen fixation.展开更多
We present an efficient controlled quantum perfect teleportation scheme. In our scheme, multiple senders can teleport multiple arbitrary unknown multi-qubit states to a single receiver via a previously shared entangle...We present an efficient controlled quantum perfect teleportation scheme. In our scheme, multiple senders can teleport multiple arbitrary unknown multi-qubit states to a single receiver via a previously shared entanglement state with the help of one or more controllers. Furthermore, our scheme has a very good performance in the measurement and operation complexity, since it only needs to perform Bell state and single-particle measurements and to apply Controlled-Not gate and other single-particle unitary operations. In addition, compared with traditional schemes, our scheme needs less qubits as the quantum resources and exchanges less classical information, and thus obtains higher communication efficiency.展开更多
We propose an efficient hyperconcentration protocol for distilling maximally hyperentangled state from partially entangled pure state, resorting to the projection measurement on an auxiliary photon. In our scheme, two...We propose an efficient hyperconcentration protocol for distilling maximally hyperentangled state from partially entangled pure state, resorting to the projection measurement on an auxiliary photon. In our scheme, two photons simultaneously entangled in polarization states and spatial modes are considered. One party performs quantum nondemolition detections on his photon and an additional photon to produce three photon hyperentangled state, then he projects the assistant photon into an orthogonal basis composed of both the polarization and spatial degree of freedom.Then the state of the left two photons collapses into maximally hyperentangled state with a certain probability. In the rest cases, some less-entangled states are obtained, which can be used as resource for the next round concentration. By repeating the concentration process for several rounds, a higher success probability can be obtained, which makes our scheme useful in practical quantum information applications.展开更多
文摘A detailed study of some simple forms which have a given special structure have been solved, in this paper, we research the extension of this kind of special structure problems.
基金Supported by Hunan Provincial Natural Science Foundation of China under Grant No.10JJ6010the Key Project Foundation of Hunan Provincial Education Department of China under Grant No.10A095
文摘We study a system consisting of two identical non-interacting single-mode cavity fields coupled to a common vacuum environment and provide general, explicit, and exact solutions to its master equation by means of the characteristic function method. We analyze the entanglement dynamics of two-mode squeezed thermal state in this model and show that its entanglement dynamics is strongly determined by the two-mode squeezing parameter and the purity. In particular, we find that two-mode squeezed thermal state with the squeezing parameter r ≤ -（1/2） In √u is extremely fragile and almost does not survive in a common vacuum environment. We investigate the time evolution of nonlocality for two-mode squeezed thermal state in such an environment. It is found that the evolved state loses its nonlocality in the beginning of the evolution, but after a time, the revival of nonlocality can occur.
基金The project supported by National Natural Science Foundation of China under Grant No.10575017
文摘We present a controlled secure quantum communication protocol using non-maximally （pure） entangled W states first, and then discuss the basic requirements for a real quantum communication. We show that the authorized two users can exchange their secret messages with the help of the controller after purifying the non-maximally entangled states quantum channel unconditionally securely and simultaneously. Our quantum communication protocol seems even more feasible within present technologies.
基金Open Foundation of Laboratory of High- Intensity Optics
文摘We introduce the three-mode entangled state and set up an experiment to generate it. Then we discuss the three-mode squeezing operator squeezed ｜p, X2, X3〉→μ^-3/2｜p/μ, X2/μ, X3/μ） and the optical implement to realize such a squeezed state. We also reveal that c-number .asymmetric shrink transform in the three-mode entangled state, i.e. ｜p, X2,X3）→μ^-1/2｜p/μ, X2,X3）, maps onto a kind of one-sided three-mode squeezing operator {iλ （∑i^3=1 Pi） （∑i^3=1 Qi） -λ/2}. Using the technique of integration within an ordered product （IWOP） of operators, we derive their normally ordered forms and construct the corresponding squeezed states.
基金Supported by the National Natural Science Foundation of China(61503019)the Beijing Natural Science Foundation(4152041)Beijing Higher Education Young Elite Teacher Project(YETP0504)
文摘State estimation of biological process variables directly influences the performance of on-line monitoring and op- timal control for fermentation process. A novel nonlinear state estimation method for fermentation process is proposed using cubature Kalman filter （CKF） to incorporate delayed measurements. The square-root version of CI（F （SCKF） algorithm is given and the system with delayed measurements is described. On this basis, the sample-state augmentation method for the SCKF algorithm is provided and the implementation of the proposed algorithm is constructed. Then a nonlinear state space model for fermentation process is established and the SCKF algorithm incorporating delayed measurements based on fermentation process model is presented to implement the nonlinear state estimation. Finally, the proposed nonlinear state estimation methodology is applied to the state estimation for penicillin and industrial yeast fermentation processes. The simulation results show that the on-fine state estimation for fermentation process can be achieved by the proposed method with higher esti- mation accuracy and better stability.
基金supported by the National Key Basic Research Program of China(2013CB921800 and 2014CB848700)the National Science Fund for Distinguished Young Scholars of China(11425523)+3 种基金the National Natural Science Foundation of China(11374375,11574405,11375167,11605153 and 11704420)the Strategic Priority Research Program(B)of the CAS(XDB01030400)the Key Research Program of Frontier Sciences of the CAS(QYZDY-SSW-SLH004)partially supported by the National Postdoctoral Program for Innovative Talents of China(BX201600198)
文摘Nonlinear quantum metrology may exhibit better precision scalings. For example, the uncertainty of an estimated phase may scale as △φ∝ 1/N2 under quadratic phase accumulation, which is 1/N times smal-ler than the linear counterpart, where N is probe number. Here, we experimentally demonstrate the non-linear quantum metrology by using a spin-I（I 〉 1/2） nuclear magnetic resonance （NMR） ensemble that can be mapped into a system ofN = 2I spin-1/2 particles and the quadratic interaction can be utilized for the quadratic phase accumulation. Our experimental results show that the phase uncertainty can scale as △φ∝1/（N2-1） by optimizing the input states, when N is an odd number. In addition, the interferomet-tic measurement with quadratic interaction provides a new way for estimating the quadrupolar coupling strength in an NMR system. Our system may be further extended to exotic nonlinear quantum metrology with higher order many-body interactions.
基金Supported in part by an International Macquarie University Research Excellence Scholarship(i MQRES),Australian Research Council Grant DP0987734also supported by the National Basic Research Program of China(973 Program)under Grant No.2010CB923200+2 种基金the National Natural Science Foundation of China under No.61377067Fund of State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications,China,National Natural Science Foundation of China under Grant Nos.61202362,61262057,61472433China Postdoctora Science Foundation under Grant No.2013M542560
文摘In this paper, we show that a(2, 3) discrete variable threshold quantum secret sharing scheme of secure direct communication can be achieved based on recurrence using the same devices as in BB84. The scheme is devised by first placing the shares of smaller secret pieces into the shares of the largest secret piece, converting the shares of the largest secret piece into corresponding quantum state sequences, inserting nonorthogonal state particles into the quantum state sequences with the purpose of detecting eavesdropping, and finally sending the new quantum state sequences to the three participants respectively. Consequently, every particle can on average carry up to 1.5-bit messages due to the use of recurrence. The control codes are randomly prepared using the way to generate fountain codes with pre-shared source codes between Alice and Bob, making three participants can detect eavesdropping by themselves without sending classical messages to Alice. Due to the flexible encoding, our scheme is also dynamic, which means that it allows the participants to join and leave freely.
基金Supported by the National Natural Science Foundation of China under Grant No. 11175033the Fundamental Research Funds of the Central Universities under Grant No. DUT12LK42
文摘In this paper, we propose a very simple scheme to probe the quantum and classical correlation including quantum entanglement of Bell diagonal state. In the probing process, the correlation of Bell diagonal state, even the state itself, is not disturbed, which means a non-destructive probing. In addition, our scheme can be performed even though the two qubits of the Bell diagonal state are separate in space.
基金supported by the National Natural Science Foundation of China (52161135302, 21674019, and 51801075)the Research Foundation Flanders (G0F2322N)+8 种基金Shanghai Scientific and Technological Innovation Project (18JC1410600)the Program of the Shanghai Academic Research Leader (17XD1400100)the financial support from the Flemish Government through the Moonshot cSBO project P2C (HBC.2019.0108)the Long-term Structural Funding (Methusalem CASAS2, Meth/15/04)Interne Fondsen KU Leuven through project C3/20/067the support from the Research Foundation-Flanders (FWO) in the form of a doctoral fellowship (1SA3321N)the financial support from China Scholarship Council in the form of a visiting Ph.D. Student (File No. 202106790090)the LvLiang Cloud Computing Center of China, and the calculations were performed on a TianHe-2 systemthe characterizations supported by the Central Laboratory, School of Chemical and Material Engineering, Jiangnan University。
文摘Despite the intense research efforts directed to electrocatalytic nitrogen reduction reaction(eNRR),the NH_(3) yield and selectivity are still not up to the standard of practical application.Here,high-entropy perovskite oxides with composition Bax(FeCoNiZrY)_(0.2)O_(3−δ)(Bx(FCNZY)_(0.2)(x=0.9,1)are reported as eNRR catalysts.The eNRR activity of high-entropy perovskite oxide is enhanced by changing the nonstoichiometric metal elements at the A-site,thus generating additional oxygen vacancies.The NH_(3) yield and Faraday efficiency for B_(0.9)(FCNZY)_(0.2) are 1.51 and 1.95 times higher than those for B(FCNZY)_(0.2),respectively.The d-band center theory is used to theoretically predict the catalytically active center at the B-site,and as a result,nickel was identified as the catalytic site.The free energy values of the intermediate states in the optimal distal pathway show that the third protonation step(*NNH_(2)→*NNH_(3))is the rate-determining step and that the increase in oxygen vacancies in the high-entropy perovskite contributes to nitrogen adsorption and reduction.This work provides a framework for applying high-entropy structures with active site diversity for electrocatalytic nitrogen fixation.
基金supported by the Major Research Plan of the National Natural Science Foundation of China (Grant No.90818005)the National Natural Science Foundation of China (Grant Nos.61173187 and 61173-188)+1 种基金the Natural Science Foundation of Anhui Province (Grant No.11040606M141)the Research Program of Anhui Province Education Department (Grant No.KJ2010A009)
文摘We present an efficient controlled quantum perfect teleportation scheme. In our scheme, multiple senders can teleport multiple arbitrary unknown multi-qubit states to a single receiver via a previously shared entanglement state with the help of one or more controllers. Furthermore, our scheme has a very good performance in the measurement and operation complexity, since it only needs to perform Bell state and single-particle measurements and to apply Controlled-Not gate and other single-particle unitary operations. In addition, compared with traditional schemes, our scheme needs less qubits as the quantum resources and exchanges less classical information, and thus obtains higher communication efficiency.
基金Supported by the National Natural Science Foundation of China under Grant No.11004258the Fundamental Research Funds for the Central Universities under Grant No.CQDXWL-2012-014
文摘We propose an efficient hyperconcentration protocol for distilling maximally hyperentangled state from partially entangled pure state, resorting to the projection measurement on an auxiliary photon. In our scheme, two photons simultaneously entangled in polarization states and spatial modes are considered. One party performs quantum nondemolition detections on his photon and an additional photon to produce three photon hyperentangled state, then he projects the assistant photon into an orthogonal basis composed of both the polarization and spatial degree of freedom.Then the state of the left two photons collapses into maximally hyperentangled state with a certain probability. In the rest cases, some less-entangled states are obtained, which can be used as resource for the next round concentration. By repeating the concentration process for several rounds, a higher success probability can be obtained, which makes our scheme useful in practical quantum information applications.
