We present a method to teleport multi-qubit quantum information in an easy way from a sender to a receiver via the control of many agents in a network. Only when all the agents collaborate with the quantum information...We present a method to teleport multi-qubit quantum information in an easy way from a sender to a receiver via the control of many agents in a network. Only when all the agents collaborate with the quantum information receiver can the unknown states in the sender＇s qubits be fully reconstructed in the receiver＇s qubits. In our method, agents＇s control parameters are obtained via quantum entanglement swapping. As the realization of the many-agent controlled teleportation is concerned, compared to the recent method [G.P. Yang, et al., Phys. Rev. A 70 （2004） 022329], our present method considerably reduces the preparation difficulty of initial states and the identification difficulty of entangled states, moreover, it does not need local Hadamard operations and it is more feasible in technology.展开更多
Based on entanglement swapping, a quantum key distribution （QKD） scheme is proposed. In this scheme, the secret keys are formed by comparing initial Bell states and outcomes of entanglement swapping. Moreover, all i...Based on entanglement swapping, a quantum key distribution （QKD） scheme is proposed. In this scheme, the secret keys are formed by comparing initial Bell states and outcomes of entanglement swapping. Moreover, all initial Bell states prepared by Alice and Bob are completely arbitrary. As the classical information exchanged between two parties is very little, this QKD scheme has a high efficiency. In addition, in order to prevent eavesdropping, decoy particles are used.展开更多
We propose two schemes for splitting single- and two-qubit states by using four-particle genuine entangled state as the quantum channel. After the sender performs Bell-basis （or three-partite GHZ- basis） measurement...We propose two schemes for splitting single- and two-qubit states by using four-particle genuine entangled state as the quantum channel. After the sender performs Bell-basis （or three-partite GHZ- basis） measurements on her particles, and the cooperators operate single-particle measurements on their particles, the state receiver can reconstruct the original state of the sender by applying the appropriate unitary operation. In particular, in the scheme for splitting two-qubit state, the receiver needs to introduce an auxiliary particle and carries out a C-NOT operation.展开更多
In this paper, a scheme is proposed to create the entanglement of two superconducting quantum-interference devices （SQUIDs） and implement a two-quhit quantum phase gate between two SQUIDs in cavity. The scheme only ...In this paper, a scheme is proposed to create the entanglement of two superconducting quantum-interference devices （SQUIDs） and implement a two-quhit quantum phase gate between two SQUIDs in cavity. The scheme only requires resonant interactions. Thus the scheme is very simple and the quantum dynamics operation can he realized at a high speed, which is important in view of decoherence.展开更多
We present a scheme for teleporting multi-qutrit quantum information from a sender to a receiver via the control of many agents in a network. Agents＇s control parameters are obtained via quantum entanglement swapping...We present a scheme for teleporting multi-qutrit quantum information from a sender to a receiver via the control of many agents in a network. Agents＇s control parameters are obtained via quantum entanglement swapping. In our scheme, Zhang and Man＇s QSS protocol [Phys. Rev. A 72 （2005） 022303] based on Bell-state entanglement swapping is generalized to a qutrit case. Our scheme owns the advantage of having higher code capacity and better security than the work [Commun. Theor. Phys. 44 （2005） 847] on controlled teleportation for multi-qubit.展开更多
In this paper, we present a scheme for teleporting multi-qudit quantum state, from the sender Alice to the receiver Charlie via many controllers Bobs, whose control parameters are obtained using entanglement swapping ...In this paper, we present a scheme for teleporting multi-qudit quantum state, from the sender Alice to the receiver Charlie via many controllers Bobs, whose control parameters are obtained using entanglement swapping of maximally d-dimensional EPR pair. In our scheme, Yang＇s qutrit controlled teleportation protocol [Commun. Theor. Phys. 49 （2008） 338] based on Bell-state entanglement swapping is generalized to the qudit case. The scheme of multi-qudit owns the advantage of having higher code capacity and better security than that of multi-qutrit.展开更多
In this paper, we propose two physical schemes for teleporting an unknown atomic state through noisy channel in cavity QED. The quantum channel is a noisy one -- a mixed GHZ state, which is more realistic in quantum i...In this paper, we propose two physical schemes for teleporting an unknown atomic state through noisy channel in cavity QED. The quantum channel is a noisy one -- a mixed GHZ state, which is more realistic in quantum information processing. We solve analytically a master equation in the Lindblad form with （L2,z, L3,z, L4,z）-type of noise in cavity Q, ED. A comparison between the two protocols are discussed.展开更多
We model of intrinsic analyze the time evolution of entanglement of two-qutrit system within the framework of Milburn＇s decoherence. The entanglement evolution relies not only on the parameters of system, but also on...We model of intrinsic analyze the time evolution of entanglement of two-qutrit system within the framework of Milburn＇s decoherence. The entanglement evolution relies not only on the parameters of system, but also on the concrete states either pure or mixed. The linear entropy used to measure the extent to which the intrinsic decoherenee affects quantum states is evaluated.展开更多
We study the degree to which quantum entanglement survives when a three-qubit entangled state iscopied by using local and non-local processes, respectively, and investigate iterating quantum copyingfor the three-qubit...We study the degree to which quantum entanglement survives when a three-qubit entangled state iscopied by using local and non-local processes, respectively, and investigate iterating quantum copyingfor the three-qubitsystem. There may exist inter-three-qubit entanglement and inter-two-qubit entanglement for the three-qubit system.We show that both local and non-local copying processes degrade quantum entanglement in the three-particle systemdue to a residual correlation between the copied output and the copying machine. We also show that the inter-two-qubitentanglement is preserved better than the inter-three-qubit entanglement in the local cloning process. We find thatnon-local cloning is much more efficient than the local copying for broadcasting entanglement, and output state vianon-local cloning exhibits the fidelity better than local cloning.展开更多
By exposing deficiency of the usual superoperators that have no explicit operator-expression in quantuminformation theory we introduce thermo entangled state representation to endow each of these superoperators a defi...By exposing deficiency of the usual superoperators that have no explicit operator-expression in quantuminformation theory we introduce thermo entangled state representation to endow each of these superoperators a definiteoperator-expression in an enlarged space in which one mode is a fictitious.This helps us to directly derive the role ofexponential of superoperators and the solutions of some master equations.展开更多
A scheme is proposed for the generation of entangled states for multiple atoms trapped in a cavity by detecting photon decay. The scheme is valid no matter when the effective atom-cavity coupling strength is larger th...A scheme is proposed for the generation of entangled states for multiple atoms trapped in a cavity by detecting photon decay. The scheme is valid no matter when the effective atom-cavity coupling strength is larger than the cavity decay rate or not, which is of importance in view of experiment. The fidelity of entanglement is insensitive to the inefticiency of the photo-detector. The scheme does not require a photon to be initially injected into the cavity.展开更多
基金the foundations of the Natural Science of Shaanxi,China(2001Sl042004A19)+1 种基金Specialized Scientific research of Education Department of Shaanxi,China(08JK286)Key Scientific research of Weinan Teachers University,China(08YKF014)~~
文摘We present a method to teleport multi-qubit quantum information in an easy way from a sender to a receiver via the control of many agents in a network. Only when all the agents collaborate with the quantum information receiver can the unknown states in the sender＇s qubits be fully reconstructed in the receiver＇s qubits. In our method, agents＇s control parameters are obtained via quantum entanglement swapping. As the realization of the many-agent controlled teleportation is concerned, compared to the recent method [G.P. Yang, et al., Phys. Rev. A 70 （2004） 022329], our present method considerably reduces the preparation difficulty of initial states and the identification difficulty of entangled states, moreover, it does not need local Hadamard operations and it is more feasible in technology.
文摘Based on entanglement swapping, a quantum key distribution （QKD） scheme is proposed. In this scheme, the secret keys are formed by comparing initial Bell states and outcomes of entanglement swapping. Moreover, all initial Bell states prepared by Alice and Bob are completely arbitrary. As the classical information exchanged between two parties is very little, this QKD scheme has a high efficiency. In addition, in order to prevent eavesdropping, decoy particles are used.
文摘We propose two schemes for splitting single- and two-qubit states by using four-particle genuine entangled state as the quantum channel. After the sender performs Bell-basis （or three-partite GHZ- basis） measurements on her particles, and the cooperators operate single-particle measurements on their particles, the state receiver can reconstruct the original state of the sender by applying the appropriate unitary operation. In particular, in the scheme for splitting two-qubit state, the receiver needs to introduce an auxiliary particle and carries out a C-NOT operation.
基金The project supported in part by National Natural Science Foundation of China under Grant No. 60478029. Acknowledgments We would like to thank Prof. Wu Ying for enlightening discussions
文摘In this paper, a scheme is proposed to create the entanglement of two superconducting quantum-interference devices （SQUIDs） and implement a two-quhit quantum phase gate between two SQUIDs in cavity. The scheme only requires resonant interactions. Thus the scheme is very simple and the quantum dynamics operation can he realized at a high speed, which is important in view of decoherence.
基金National Natural Science Foundation of China under Grant Nos.60677001 and 10304022the Science-Technology Fund of Anhui Province for Outstanding Youth under Grant No.06042087+1 种基金the General Fund of the Educational Committee of Anhui Province under Grant No.2006KJ260Bthe Key Fund of the Ministry of Education of China under Grant No.206063
文摘We present a scheme for teleporting multi-qutrit quantum information from a sender to a receiver via the control of many agents in a network. Agents＇s control parameters are obtained via quantum entanglement swapping. In our scheme, Zhang and Man＇s QSS protocol [Phys. Rev. A 72 （2005） 022303] based on Bell-state entanglement swapping is generalized to a qutrit case. Our scheme owns the advantage of having higher code capacity and better security than the work [Commun. Theor. Phys. 44 （2005） 847] on controlled teleportation for multi-qubit.
基金supported by Tianjin Natural Science Fund under Grant No.06YFJMJC00800
文摘In this paper, we present a scheme for teleporting multi-qudit quantum state, from the sender Alice to the receiver Charlie via many controllers Bobs, whose control parameters are obtained using entanglement swapping of maximally d-dimensional EPR pair. In our scheme, Yang＇s qutrit controlled teleportation protocol [Commun. Theor. Phys. 49 （2008） 338] based on Bell-state entanglement swapping is generalized to the qudit case. The scheme of multi-qudit owns the advantage of having higher code capacity and better security than that of multi-qutrit.
基金Supported by National Natural Science Foundation of China under Grant Nos. 60678022 and 10704001the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No. 20060357008+2 种基金Anhui Provincial Natural Science Foundation under Grant No. 070412060the Key Program of the Education Department of Anhui Province under Grant Nos.KJ2008A28ZC,KJ2008B265,KJ2009A048Z, 2010SQRLI53ZD, and 2008JQI183the Talent Foundation of Anhui University and Anhui Key Laboratory of Information Materials and Devices (Anhui University)
文摘In this paper, we propose two physical schemes for teleporting an unknown atomic state through noisy channel in cavity QED. The quantum channel is a noisy one -- a mixed GHZ state, which is more realistic in quantum information processing. We solve analytically a master equation in the Lindblad form with （L2,z, L3,z, L4,z）-type of noise in cavity Q, ED. A comparison between the two protocols are discussed.
基金the National Fundamental Research Program of China under Grant No.60573008
文摘We model of intrinsic analyze the time evolution of entanglement of two-qutrit system within the framework of Milburn＇s decoherence. The entanglement evolution relies not only on the parameters of system, but also on the concrete states either pure or mixed. The linear entropy used to measure the extent to which the intrinsic decoherenee affects quantum states is evaluated.
基金the National Fundamental Research Program，国家自然科学基金，教育部EYTF项目，湖南省科研项目
文摘We study the degree to which quantum entanglement survives when a three-qubit entangled state iscopied by using local and non-local processes, respectively, and investigate iterating quantum copyingfor the three-qubitsystem. There may exist inter-three-qubit entanglement and inter-two-qubit entanglement for the three-qubit system.We show that both local and non-local copying processes degrade quantum entanglement in the three-particle systemdue to a residual correlation between the copied output and the copying machine. We also show that the inter-two-qubitentanglement is preserved better than the inter-three-qubit entanglement in the local cloning process. We find thatnon-local cloning is much more efficient than the local copying for broadcasting entanglement, and output state vianon-local cloning exhibits the fidelity better than local cloning.
基金Supported by the President Foundation of Chinese Academy of Science
文摘By exposing deficiency of the usual superoperators that have no explicit operator-expression in quantuminformation theory we introduce thermo entangled state representation to endow each of these superoperators a definiteoperator-expression in an enlarged space in which one mode is a fictitious.This helps us to directly derive the role ofexponential of superoperators and the solutions of some master equations.
基金The project supported by National Natural Science Foundation of China under Grant No. 10225421 and the Funds from Fuzhou University
文摘A scheme is proposed for the generation of entangled states for multiple atoms trapped in a cavity by detecting photon decay. The scheme is valid no matter when the effective atom-cavity coupling strength is larger than the cavity decay rate or not, which is of importance in view of experiment. The fidelity of entanglement is insensitive to the inefticiency of the photo-detector. The scheme does not require a photon to be initially injected into the cavity.
