We mostly investigate two schemes. One is to teleport a multi-mode W-type entangled coherent state using a peculiar bipartite entangled state as the quantum channel different from other proposals. Based on our formali...We mostly investigate two schemes. One is to teleport a multi-mode W-type entangled coherent state using a peculiar bipartite entangled state as the quantum channel different from other proposals. Based on our formalism,teleporting multi-mode coherent state or squeezed state is also possible. Another is that the tripartite entangled state is used as the quantum channel of controlled teleportation of an arbitrary and unknown continuous variable in the case of three participators.展开更多
A quantum teleportation scheme to teleport a kind of tripartite entangled states of continuous variables by using a quantum channel composed of three bipartite entangled states is proposed. The joint Bell measurement ...A quantum teleportation scheme to teleport a kind of tripartite entangled states of continuous variables by using a quantum channel composed of three bipartite entangled states is proposed. The joint Bell measurement is feasible because the bipartite entangled states are complete and the squeezed state has a natural representation in the entangled state basis. The calculation is greatly simplified by using the Schmidt decomposition of the entangled states.展开更多
We present a realistic scheme for the entanglement swapping of continuous variable, in which a two-mode squeezed vacuum state serves as a quantum channel. The position sum and momentum difference of two local modes ar...We present a realistic scheme for the entanglement swapping of continuous variable, in which a two-mode squeezed vacuum state serves as a quantum channel. The position sum and momentum difference of two local modes are measured. By taking the input entangled state also as a two-mode squeezed vacuum state, we investigate the average fidelity and the yon Neumann entropy of the output state. The results show that the perfect teleportation can be achieved by increasing the squeezing of the quantum channel and that any nonzero squeezing in both the quantum channel and the input entangled state is sufficient to swap the entanglement.展开更多
We propose a scheme for controlled entanglement swapping of continuous variable, where an EPR pair shared by two parties （Alice and Debbie） and a GHZ entangled state shared by three parties （Alice, Bob and Claire）...We propose a scheme for controlled entanglement swapping of continuous variable, where an EPR pair shared by two parties （Alice and Debbie） and a GHZ entangled state shared by three parties （Alice, Bob and Claire） are required. One optical beams of the EPR state will be entangled with the output mode displaced by Bob with the help of Claire. It is shown that the entanglement swapping can occur controlled by the third party （Claire）展开更多
Based on the coherent entangled state ｜a, x〉 we introduce the squeezed entangled state （SES）. Then we propose a teleportation protocol for the SES by using Einstein-Podolsky-Rosen entangled state ｜η〉 as a quant...Based on the coherent entangled state ｜a, x〉 we introduce the squeezed entangled state （SES）. Then we propose a teleportation protocol for the SES by using Einstein-Podolsky-Rosen entangled state ｜η〉 as a quantum channel. The calculation is greatly simplified by virtue of the Schmidt decompositions of both ｜a, x〉 and ｜η〉. Any bipartite states that can be expanded in terms of ｜a, x〉 may be teleported in this way due to the completeness of ｜a, x〉.展开更多
We designed the experimental generation system of the optical GHZ-like and cluster-like quadripartite entangled states for continuous variables.We theoretically demonstrated that the two different types of quadriparti...We designed the experimental generation system of the optical GHZ-like and cluster-like quadripartite entangled states for continuous variables.We theoretically demonstrated that the two different types of quadripartite entangled states can be obtained by the linearly optical transformation of four amplitude-quadrature and phase-quadrature squeezed states produced from a pair of nondegenerate optical parametric amplifiers under appropriate phase relations.The criteria for full inseparability of quadripartite cluster-like state were deduced,and the dependency of the quadripartite entanglement on the initial squeezing degree,the transmission efficiencies of the system and the detection efficiency of homodyne detection were numerically calculated.展开更多
The generalized continuous variable two-mode entangled state |?> is proposed by using the technique of integration within an ordered product (IWOP) of operators. The characteristics of this new entangled representa...The generalized continuous variable two-mode entangled state |?> is proposed by using the technique of integration within an ordered product (IWOP) of operators. The characteristics of this new entangled representation and its application in quantum teleportation are analyzed in detail. These results indicate that such real parameters |?> indeed make up a new entangled representation owing to its completeness and orthogonal relation. By employing the |?> as quantum transmission channel, the teleportation of any single-mode quantum state 3 |ψ>3 can be realized by a unitary transformation.展开更多
We demonstrate experimentally the simultaneous generation and detection of two types of continuous variable nonclassical states from one type-0 phase-matching optical parametric armplification(OPA)and subsequent two r...We demonstrate experimentally the simultaneous generation and detection of two types of continuous variable nonclassical states from one type-0 phase-matching optical parametric armplification(OPA)and subsequent two ring filter cavities(RFCs).The output field of the OPA includes the baseband wo and sideband modes ω0±nωf subjects to the cavity resonance condition,which are separated by two cascaded RFCs.The first RFC resonates with half the pump wavelength wo and the transmitted baseband component is a squeezed state.The relcted fields of the first RFC,including the sideband modes ω0±wf,are separated by the second RFC,construct Einstein Podolsky-Rosen entangled state.All freedoms,including the filter cavities for sideband separation and relative phases for the measure-ments of these sidebands,are actively stabilized.The noise variance of squeezed states is 10.2 dB below the shot noise limit(SNL),the correlation variances of both quadrature amplitude-sum and quadrature phase diference for the entanglement state are 10.0 dB below the corresponding SNL.展开更多
The fidelity of quantum teleportation of a single-mode squeezed state of light is calculated based on the general theory of quantum-mechanical measurement in the Schrodinger picture. It is shown that the criterion for...The fidelity of quantum teleportation of a single-mode squeezed state of light is calculated based on the general theory of quantum-mechanical measurement in the Schrodinger picture. It is shown that the criterion for the nonclassical state teleportation is different from that for coherent state. F = 1/2 is no longer the rigorous boundary between classical and quantum teleportation for a squeezed state of light. When the quantum entanglement of an Einstein-Podolsky-Rosen （EPR） beam used for teleportation and the parameters of the system are given, the fidelity depends on the squeezing of the input squeezed state. The higher the squeezing is, the smaller the fidelity is, and the lower the classical limitation of fidelity is. The dependence of the optimum gain for teleporting a squeezed vacuum state upon the EPR entanglement is also calculated. The results obtained provide important references for designing experimental systems of teleporting a non-classical state and judging the quality of the teleported quantum state.展开更多
The preparation of multipartite entangled states is the prerequisite for exploring quantum information networks and quantum computation.In this paper,we review the experimental progress in the preparation of cluster s...The preparation of multipartite entangled states is the prerequisite for exploring quantum information networks and quantum computation.In this paper,we review the experimental progress in the preparation of cluster states and multi-color entangled states with continuous variables.The preparation of lager scale multipartite entangled state provide valuable quantum resources to implement more complex quantum informational tasks.展开更多
文摘We mostly investigate two schemes. One is to teleport a multi-mode W-type entangled coherent state using a peculiar bipartite entangled state as the quantum channel different from other proposals. Based on our formalism,teleporting multi-mode coherent state or squeezed state is also possible. Another is that the tripartite entangled state is used as the quantum channel of controlled teleportation of an arbitrary and unknown continuous variable in the case of three participators.
文摘A quantum teleportation scheme to teleport a kind of tripartite entangled states of continuous variables by using a quantum channel composed of three bipartite entangled states is proposed. The joint Bell measurement is feasible because the bipartite entangled states are complete and the squeezed state has a natural representation in the entangled state basis. The calculation is greatly simplified by using the Schmidt decomposition of the entangled states.
基金Project supported by the National Natural Science Foundation of China （Grant No 20477043）.
文摘We present a realistic scheme for the entanglement swapping of continuous variable, in which a two-mode squeezed vacuum state serves as a quantum channel. The position sum and momentum difference of two local modes are measured. By taking the input entangled state also as a two-mode squeezed vacuum state, we investigate the average fidelity and the yon Neumann entropy of the output state. The results show that the perfect teleportation can be achieved by increasing the squeezing of the quantum channel and that any nonzero squeezing in both the quantum channel and the input entangled state is sufficient to swap the entanglement.
基金The project supported by National Natural Science Foundation of China(NSFC)under Grant Nos.60678022 and 10704001the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No.20060357008+2 种基金Natural Science Foundation of Anhui Province under Grant No.070412060the Key Program of the Education Department of Anhui Province under Grant No.2006KJ070Athe Talent Foundation of Anhui University,and Anhui Key Laboratory of Information Materials and Devices(Anhui University)
文摘We propose a scheme for controlled entanglement swapping of continuous variable, where an EPR pair shared by two parties （Alice and Debbie） and a GHZ entangled state shared by three parties （Alice, Bob and Claire） are required. One optical beams of the EPR state will be entangled with the output mode displaced by Bob with the help of Claire. It is shown that the entanglement swapping can occur controlled by the third party （Claire）
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10475056 and 10647133, and the Research Foundation of the Education Department of Jiangxi Province under Grant No. [2007]22
文摘Based on the coherent entangled state ｜a, x〉 we introduce the squeezed entangled state （SES）. Then we propose a teleportation protocol for the SES by using Einstein-Podolsky-Rosen entangled state ｜η〉 as a quantum channel. The calculation is greatly simplified by virtue of the Schmidt decompositions of both ｜a, x〉 and ｜η〉. Any bipartite states that can be expanded in terms of ｜a, x〉 may be teleported in this way due to the completeness of ｜a, x〉.
基金Supported by the National Natural Science Foundation of China(Grant Nos.10674088 and 60608012)Program for Changjiang Scholars andInnovative Research Team in University(Grant No.IRT0516)
文摘We designed the experimental generation system of the optical GHZ-like and cluster-like quadripartite entangled states for continuous variables.We theoretically demonstrated that the two different types of quadripartite entangled states can be obtained by the linearly optical transformation of four amplitude-quadrature and phase-quadrature squeezed states produced from a pair of nondegenerate optical parametric amplifiers under appropriate phase relations.The criteria for full inseparability of quadripartite cluster-like state were deduced,and the dependency of the quadripartite entanglement on the initial squeezing degree,the transmission efficiencies of the system and the detection efficiency of homodyne detection were numerically calculated.
文摘The generalized continuous variable two-mode entangled state |?> is proposed by using the technique of integration within an ordered product (IWOP) of operators. The characteristics of this new entangled representation and its application in quantum teleportation are analyzed in detail. These results indicate that such real parameters |?> indeed make up a new entangled representation owing to its completeness and orthogonal relation. By employing the |?> as quantum transmission channel, the teleportation of any single-mode quantum state 3 |ψ>3 can be realized by a unitary transformation.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.11654002,11804207,11874250,and 11804206)the National Key Research and Development Program of China(Grant No.2016YFA0301401)+1 种基金the Program for Sanjin Scholar of Shanxi Province,the Key Research and Development Program of Shanxi(Grant No.201903D111001)the Fund for Shanxi 1331 Project Key Subjects Construction,the Program for Outstanding Innovative Teams of Higher Learning In-stitutions of Shanxi,and the Natural Science Foundation of Shanxi Province(Grant No.201801D221006).
文摘We demonstrate experimentally the simultaneous generation and detection of two types of continuous variable nonclassical states from one type-0 phase-matching optical parametric armplification(OPA)and subsequent two ring filter cavities(RFCs).The output field of the OPA includes the baseband wo and sideband modes ω0±nωf subjects to the cavity resonance condition,which are separated by two cascaded RFCs.The first RFC resonates with half the pump wavelength wo and the transmitted baseband component is a squeezed state.The relcted fields of the first RFC,including the sideband modes ω0±wf,are separated by the second RFC,construct Einstein Podolsky-Rosen entangled state.All freedoms,including the filter cavities for sideband separation and relative phases for the measure-ments of these sidebands,are actively stabilized.The noise variance of squeezed states is 10.2 dB below the shot noise limit(SNL),the correlation variances of both quadrature amplitude-sum and quadrature phase diference for the entanglement state are 10.0 dB below the corresponding SNL.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60278010, 60238010, and 60478808, the Shanxi Natural Science Foundation under Grant No 20041039, and the Returned Scholar Foundation.
文摘The fidelity of quantum teleportation of a single-mode squeezed state of light is calculated based on the general theory of quantum-mechanical measurement in the Schrodinger picture. It is shown that the criterion for the nonclassical state teleportation is different from that for coherent state. F = 1/2 is no longer the rigorous boundary between classical and quantum teleportation for a squeezed state of light. When the quantum entanglement of an Einstein-Podolsky-Rosen （EPR） beam used for teleportation and the parameters of the system are given, the fidelity depends on the squeezing of the input squeezed state. The higher the squeezing is, the smaller the fidelity is, and the lower the classical limitation of fidelity is. The dependence of the optimum gain for teleporting a squeezed vacuum state upon the EPR entanglement is also calculated. The results obtained provide important references for designing experimental systems of teleporting a non-classical state and judging the quality of the teleported quantum state.
基金supported by the National Basic Research Program of China(Grant No.2010CB923103)the National Natural Science Foundation of China(Grant Nos.11322440,11074157,11174188 and 61121064)OIT and Shanxi Scholarship Council of China(Grant No.2012-010)
文摘The preparation of multipartite entangled states is the prerequisite for exploring quantum information networks and quantum computation.In this paper,we review the experimental progress in the preparation of cluster states and multi-color entangled states with continuous variables.The preparation of lager scale multipartite entangled state provide valuable quantum resources to implement more complex quantum informational tasks.
