A new bipartite coherent-entangled state is introduced in the two-mode Fock space, which exhibits the properties of both a coherent state and an entangled state. The set of coherent-entangled states makes up a complet...A new bipartite coherent-entangled state is introduced in the two-mode Fock space, which exhibits the properties of both a coherent state and an entangled state. The set of coherent-entangled states makes up a complete and partly nonorthogonal representation. A simple experimental scheme to produce the coherent-entangled state using an asymmetric beamsplitter is proposed. Some applications of the coherent-entangled state in quantum optics are also oresented.展开更多
We consider how to teleport two- and three-mode Einstein-Podolsky Rosen entangled states (|η) and |Pt, X2, X3)) via a |Pt, X2, X3) quantum channel for continuous variables. Using the complete and orthogonal r...We consider how to teleport two- and three-mode Einstein-Podolsky Rosen entangled states (|η) and |Pt, X2, X3)) via a |Pt, X2, X3) quantum channel for continuous variables. Using the complete and orthogonal representation of the entangled states, we can not only find the a complete basis set for the joint measurement but also propose the specific scheme of teleportation. Our calculation can be greatly simplified by using their Schmidt decompositions.展开更多
This paper presents a scheme for quantum secure direct communication with quantum encryption. The two authorized users use repeatedly a sequence of the pure entangled pairs (quantum key) shared for encrypting and de...This paper presents a scheme for quantum secure direct communication with quantum encryption. The two authorized users use repeatedly a sequence of the pure entangled pairs (quantum key) shared for encrypting and decrypting the secret message carried by the travelling photons directly. For checking eavesdropping, the two parties perform the single-photon measurements on some decoy particles before each round. This scheme has the advantage that the pure entangled quantum signal source is feasible at present and any eavesdropper cannot steal the message.展开更多
An alternative scheme is presented for teleportation of a two-atom entangled state in cavity quantum electrodynamics (QED). It is based on the resonant atom-cavity field interaction. In the scheme, only one cavity i...An alternative scheme is presented for teleportation of a two-atom entangled state in cavity quantum electrodynamics (QED). It is based on the resonant atom-cavity field interaction. In the scheme, only one cavity is involved, and the number of the atoms needed to be detected is decreased compared with the previous scheme. Since the resonant atom-cavity field interaction greatly reduces the interaction time, the decoherence effect can be effectively suppressed during the teleportation process. The experimental feasibility of the scheme is discussed. The scheme can easily be generalized to the teleportation of N-atom Greeninger-Horne-Zeilinger (GHZ) entangled states. The number of atoms needed to be detected does not increase as the number of the atoms in the GHZ state increases.展开更多
A scheme for remotely preparing a two-atom entangled state via entanglement swapping in cavity quantum electronic dynamics (QED) with the help of separate measurements is proposed. And the effect of cavity decay is ...A scheme for remotely preparing a two-atom entangled state via entanglement swapping in cavity quantum electronic dynamics (QED) with the help of separate measurements is proposed. And the effect of cavity decay is eliminated in our scheme.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
Based on A.K. Pati's original idea [Phys. Rev. A 61 (2000) 022308] on single-qubit-state-assisted clone, very recently Zhan has proposed two assisted quantum cloning protocols of a special class of unknown two-qubi...Based on A.K. Pati's original idea [Phys. Rev. A 61 (2000) 022308] on single-qubit-state-assisted clone, very recently Zhan has proposed two assisted quantum cloning protocols of a special class of unknown two-qubit entangled states [Phys. Lett. A 336 (2005) 317]. In this paper we further generalize Zhan's protocols such that an arbitrary unknown two-qubit entangled state can be treated.展开更多
Based on the technique of integration within an ordered product of operators, we derive new bosonic operators, ordering identities by using entangled state representation and the properties of two-variable Hermite pol...Based on the technique of integration within an ordered product of operators, we derive new bosonic operators, ordering identities by using entangled state representation and the properties of two-variable Hermite polynomials , and vice versa. In doing so, some concise normally (antinormally) ordering operator identities, such as : are obtained.展开更多
A Scheme for teleporting an unknown four-particle entangled state is proposed via entangled swapping. In this scheme, four pairs of entangled particles are used as quantum channel. It is shown that, if the four pairs ...A Scheme for teleporting an unknown four-particle entangled state is proposed via entangled swapping. In this scheme, four pairs of entangled particles are used as quantum channel. It is shown that, if the four pairs of particles are nonmaximally entangled, the teleportation can be successfully realized with certain probability if a receiver adopts some appropriate unitary transformations.展开更多
We propose a scheme capable of performing complete Bell-state analysis for a single-photon hybrid entangled state.Our single-photon state is encoded in both polarization and frequency degrees of freedom.The setup of t...We propose a scheme capable of performing complete Bell-state analysis for a single-photon hybrid entangled state.Our single-photon state is encoded in both polarization and frequency degrees of freedom.The setup of the scheme is composed of polarizing beam splitters,half wave plates,frequency shifters,and independent wavelength division multiplexers,which are feasible using current technology.We also show that with this setup we can perform complete two-photon Bell-state analysis schemes for polarization degrees of freedom.Moreover,it can also be used to perform the teleportation scheme between different degrees of freedom.This setup may allow extensive applications in current quantum communications.展开更多
We propose a scheme for teleportation of an unknown N-atom state using a two-atom entangled state within a cavity QED and show the feasibility in experiment. Our scheme does not involve the Bell-state measurement and ...We propose a scheme for teleportation of an unknown N-atom state using a two-atom entangled state within a cavity QED and show the feasibility in experiment. Our scheme does not involve the Bell-state measurement and is insensitive to the cavity decay, which is important from the experimental point of view. Another feature of the scheme is that teleporting a N-atom state just requires a small amount of entanglement (i,e. a two-atom entangled state) and less classical bits (two bits).展开更多
In this paper, we discuss the concepts of quantum coding and error correction for a five-particle entangled state. Error correction can correct bit-reverse or phase-flip errors of one and two quantum states and is no ...In this paper, we discuss the concepts of quantum coding and error correction for a five-particle entangled state. Error correction can correct bit-reverse or phase-flip errors of one and two quantum states and is no longer limited to only one quantum state. We encode a single quantum state into a five-particle entangled state before being transferred to the sender. We designed an automatic error-correction circuit to correct errors caused by noise. We also simplify the design process for a multiple quantum error-correction circuit. We compare error-correction schemes for five and three entangled particles in terms of efficiency and capabilities. The results show that error-correction efficiency and fidelity are im- proved.展开更多
We propose a scheme for teleporting a two-atom entangled state in cavity quantum electrodynamics (QED), In the scheme, we choose a single Einstein Podolsky Rosen (EPR) pair as the quantmn channel which is shared b...We propose a scheme for teleporting a two-atom entangled state in cavity quantum electrodynamics (QED), In the scheme, we choose a single Einstein Podolsky Rosen (EPR) pair as the quantmn channel which is shared by the sender and the receiver. By using the atom cavity-field interaction and introducing an additional atom, we can teleport the two-atom entangled state successfully with a probability of 1.0. Moreover, we show that the scheme is insensitive to cavity decay and thermal field.展开更多
By using the explicit form of the entangled Wigner operator and the entangled state representation we derive the relationship between wave function and corresponding Wigner function for bipartite entangled systems. Th...By using the explicit form of the entangled Wigner operator and the entangled state representation we derive the relationship between wave function and corresponding Wigner function for bipartite entangled systems. The technique of integration within an ordered product (IWOP) of operators is employed in our discussions.展开更多
We propose a simple scheme to generate x-type four-charge entangled states by using SQUID-based charge qubits capacitively coupled to a transmission line resonator (TLR). The coupling between the superconducting qub...We propose a simple scheme to generate x-type four-charge entangled states by using SQUID-based charge qubits capacitively coupled to a transmission line resonator (TLR). The coupling between the superconducting qubit and the TLR can be effectively controlled by properly adjusting the control parameters of the charge qubit. The experimental feasibility of our scheme is also shown.展开更多
In this paper, two schemes for teleporting an unknown three-particle three-level entangled state are proposed. In the first scheme, two partial three-particle three-level entangled states are used as the quantum chann...In this paper, two schemes for teleporting an unknown three-particle three-level entangled state are proposed. In the first scheme, two partial three-particle three-level entangled states are used as the quantum channels, while in the second scheme, three two-particle three-level non-maximally entangled states are employed as quantum channels. It is shown that the teleportation can be successfully realized with certain probability, for both two schemes, ira receiver adopts some appropriate unitary transformations. It is shown also that the successful probabilities of these two schemes are different.展开更多
We present a scheme for probabilistically teleporting an unknown three-level bipartite entangled state by using a partial entangled three-level bipartite state as quantum channel This scheme can be directly generalize...We present a scheme for probabilistically teleporting an unknown three-level bipartite entangled state by using a partial entangled three-level bipartite state as quantum channel This scheme can be directly generalized to probabilistically teleport an unknown three-level k-particle entangled state by a partial three-level bipartite entangled state. A11 kinds of unitary transformations are given in detail We calculate the successful total probability and the total classical communication cost required for this scheme.展开更多
Following a recent proposal (Phys. Left. A 346 (2005) 330) about quantum dense coding using a tripartite entangled GHZ state and W state, this paper proposes an experimentally feasible scheme for dense coding in c...Following a recent proposal (Phys. Left. A 346 (2005) 330) about quantum dense coding using a tripartite entangled GHZ state and W state, this paper proposes an experimentally feasible scheme for dense coding in cavity QED by using another peculiar tripartite entangled state. In the scheme the atoms interact simultaneously with a highly detuned cavity mode with the assistance of a classical field, the successful probability of dense coding scheme with this peculiar tripartite entangled state equals 1.展开更多
This paper proposes a scheme where one can realize quantum cloning of an unknown two-atom entangled state with assistance of a state preparer in cavity QED. The first stage of the scheme requires usual teleportation. ...This paper proposes a scheme where one can realize quantum cloning of an unknown two-atom entangled state with assistance of a state preparer in cavity QED. The first stage of the scheme requires usual teleportation. In the second stage of the scheme, with the assistance of the preparer, the perfect copies of an unknown atomic entangled state can be produced.展开更多
The sender shares six-particle maximally entangled states as quantum channel with the receiver. If the quantum channel is secure, the sender performs projective measurements and tells the measurement outcome to the re...The sender shares six-particle maximally entangled states as quantum channel with the receiver. If the quantum channel is secure, the sender performs projective measurements and tells the measurement outcome to the receiver. The receiver performs the unitary transformations and makes projective measurements on his particles to obtain the secret information. Using teleportation, the transmission of three-qubit secret information can be completed in each quantum channel展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 11147009)the Natural Science Foundation of Shandong Province, China (Grant No. ZR2010AQ027)the Shandong Provincial Higher Educational Science and Technology Program, China (Grant No. J09LA07)
文摘A new bipartite coherent-entangled state is introduced in the two-mode Fock space, which exhibits the properties of both a coherent state and an entangled state. The set of coherent-entangled states makes up a complete and partly nonorthogonal representation. A simple experimental scheme to produce the coherent-entangled state using an asymmetric beamsplitter is proposed. Some applications of the coherent-entangled state in quantum optics are also oresented.
基金Project supported by the National Natural Science Foundation of China (Grant No 10475056).
文摘We consider how to teleport two- and three-mode Einstein-Podolsky Rosen entangled states (|η) and |Pt, X2, X3)) via a |Pt, X2, X3) quantum channel for continuous variables. Using the complete and orthogonal representation of the entangled states, we can not only find the a complete basis set for the joint measurement but also propose the specific scheme of teleportation. Our calculation can be greatly simplified by using their Schmidt decompositions.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10604008 and 10435020) and the Beijing Education Committee (Grant No XK100270454).
文摘This paper presents a scheme for quantum secure direct communication with quantum encryption. The two authorized users use repeatedly a sequence of the pure entangled pairs (quantum key) shared for encrypting and decrypting the secret message carried by the travelling photons directly. For checking eavesdropping, the two parties perform the single-photon measurements on some decoy particles before each round. This scheme has the advantage that the pure entangled quantum signal source is feasible at present and any eavesdropper cannot steal the message.
基金Project supported by the National Natural Science Foundation of China (Grant No 10225421).
文摘An alternative scheme is presented for teleportation of a two-atom entangled state in cavity quantum electrodynamics (QED). It is based on the resonant atom-cavity field interaction. In the scheme, only one cavity is involved, and the number of the atoms needed to be detected is decreased compared with the previous scheme. Since the resonant atom-cavity field interaction greatly reduces the interaction time, the decoherence effect can be effectively suppressed during the teleportation process. The experimental feasibility of the scheme is discussed. The scheme can easily be generalized to the teleportation of N-atom Greeninger-Horne-Zeilinger (GHZ) entangled states. The number of atoms needed to be detected does not increase as the number of the atoms in the GHZ state increases.
基金Project supported by the National Natural Science Foundation of China (Grant No 60261002) and the Science Foundation of Yanbian University (Grant No 2005-20).
文摘A scheme for remotely preparing a two-atom entangled state via entanglement swapping in cavity quantum electronic dynamics (QED) with the help of separate measurements is proposed. And the effect of cavity decay is eliminated in our scheme.
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 by National Natural Science Foundation of China under Grant No. 10304022, the Science-Technology Fund of Anhui Province for 0utstanding Youth under Grant No. 06042087, the Key Fund of the Ministry of Education of China under Grant No. 206063, Natural Science Foundation of Hubei Province of China under Grant No, 2006ABA354
文摘Based on A.K. Pati's original idea [Phys. Rev. A 61 (2000) 022308] on single-qubit-state-assisted clone, very recently Zhan has proposed two assisted quantum cloning protocols of a special class of unknown two-qubit entangled states [Phys. Lett. A 336 (2005) 317]. In this paper we further generalize Zhan's protocols such that an arbitrary unknown two-qubit entangled state can be treated.
文摘Based on the technique of integration within an ordered product of operators, we derive new bosonic operators, ordering identities by using entangled state representation and the properties of two-variable Hermite polynomials , and vice versa. In doing so, some concise normally (antinormally) ordering operator identities, such as : are obtained.
文摘A Scheme for teleporting an unknown four-particle entangled state is proposed via entangled swapping. In this scheme, four pairs of entangled particles are used as quantum channel. It is shown that, if the four pairs of particles are nonmaximally entangled, the teleportation can be successfully realized with certain probability if a receiver adopts some appropriate unitary transformations.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11104159,61201164,and 61271238)the Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics Scientific,Tsinghua University,China+2 种基金the Open Research Fund Program of National Laboratory of Solid State Microstructures,Nanjing University,China (Grant Nos. M25020 and M25022)the Priority Academic Development Program of Jiangsu Higher Education Institutions,China,the Open Research Fund of National Mobile Communications Research Laboratory of Southeast University,China (Grant No. 2011D05)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20123223110003)
文摘We propose a scheme capable of performing complete Bell-state analysis for a single-photon hybrid entangled state.Our single-photon state is encoded in both polarization and frequency degrees of freedom.The setup of the scheme is composed of polarizing beam splitters,half wave plates,frequency shifters,and independent wavelength division multiplexers,which are feasible using current technology.We also show that with this setup we can perform complete two-photon Bell-state analysis schemes for polarization degrees of freedom.Moreover,it can also be used to perform the teleportation scheme between different degrees of freedom.This setup may allow extensive applications in current quantum communications.
基金Project supported by the National Natural Science Foundation of China (Grant No 10374025) and the Scientific Research Fund of Hunan Provincial Education Department (Grant No 01c260).
文摘We propose a scheme for teleportation of an unknown N-atom state using a two-atom entangled state within a cavity QED and show the feasibility in experiment. Our scheme does not involve the Bell-state measurement and is insensitive to the cavity decay, which is important from the experimental point of view. Another feature of the scheme is that teleporting a N-atom state just requires a small amount of entanglement (i,e. a two-atom entangled state) and less classical bits (two bits).
文摘In this paper, we discuss the concepts of quantum coding and error correction for a five-particle entangled state. Error correction can correct bit-reverse or phase-flip errors of one and two quantum states and is no longer limited to only one quantum state. We encode a single quantum state into a five-particle entangled state before being transferred to the sender. We designed an automatic error-correction circuit to correct errors caused by noise. We also simplify the design process for a multiple quantum error-correction circuit. We compare error-correction schemes for five and three entangled particles in terms of efficiency and capabilities. The results show that error-correction efficiency and fidelity are im- proved.
基金Project supported by the Science Foundation of Yanbian University, China (Grant No 2005-20).
文摘We propose a scheme for teleporting a two-atom entangled state in cavity quantum electrodynamics (QED), In the scheme, we choose a single Einstein Podolsky Rosen (EPR) pair as the quantmn channel which is shared by the sender and the receiver. By using the atom cavity-field interaction and introducing an additional atom, we can teleport the two-atom entangled state successfully with a probability of 1.0. Moreover, we show that the scheme is insensitive to cavity decay and thermal field.
基金The project supported by the Natural Science Foundation of Heze University of Shandong Province of China under Grant Nos.XY07WL01 and XY05WL01the University Experimental Technology Foundation of Shandong Province of China under Grant No.S04W138
文摘By using the explicit form of the entangled Wigner operator and the entangled state representation we derive the relationship between wave function and corresponding Wigner function for bipartite entangled systems. The technique of integration within an ordered product (IWOP) of operators is employed in our discussions.
基金supported by the National Natural Science Foundations of China (Grant Nos. 10947017/A05 and 11074190)the Science Foundation of the Key Laboratory of Novel Thin Film Solar Cells, China (Grant No. KF200912)the Graduates' Innovative Scientific Research Project of Zhejiang Province, China (Grant No. 2011831)
文摘We propose a simple scheme to generate x-type four-charge entangled states by using SQUID-based charge qubits capacitively coupled to a transmission line resonator (TLR). The coupling between the superconducting qubit and the TLR can be effectively controlled by properly adjusting the control parameters of the charge qubit. The experimental feasibility of our scheme is also shown.
基金The project supported by the Natural Science Foundation of Education Bureau of Jingsu Province of China under Grant No. 04KJB140014
文摘In this paper, two schemes for teleporting an unknown three-particle three-level entangled state are proposed. In the first scheme, two partial three-particle three-level entangled states are used as the quantum channels, while in the second scheme, three two-particle three-level non-maximally entangled states are employed as quantum channels. It is shown that the teleportation can be successfully realized with certain probability, for both two schemes, ira receiver adopts some appropriate unitary transformations. It is shown also that the successful probabilities of these two schemes are different.
基金The project supported by National Natural Science Foundation of China under Grant No.60674040China Postdoctoral Science Foundation
文摘We present a scheme for probabilistically teleporting an unknown three-level bipartite entangled state by using a partial entangled three-level bipartite state as quantum channel This scheme can be directly generalized to probabilistically teleport an unknown three-level k-particle entangled state by a partial three-level bipartite entangled state. A11 kinds of unitary transformations are given in detail We calculate the successful total probability and the total classical communication cost required for this scheme.
基金Project supported by Youth Foundation of Hubei Province, China (Grant No 2004Q001), the Key Program of Hubei Province, China (Grant No Z20052201) and Natural Science Foundation of Hubei Province, China (Grant No 2006ABA055).
文摘Following a recent proposal (Phys. Left. A 346 (2005) 330) about quantum dense coding using a tripartite entangled GHZ state and W state, this paper proposes an experimentally feasible scheme for dense coding in cavity QED by using another peculiar tripartite entangled state. In the scheme the atoms interact simultaneously with a highly detuned cavity mode with the assistance of a classical field, the successful probability of dense coding scheme with this peculiar tripartite entangled state equals 1.
文摘This paper proposes a scheme where one can realize quantum cloning of an unknown two-atom entangled state with assistance of a state preparer in cavity QED. The first stage of the scheme requires usual teleportation. In the second stage of the scheme, with the assistance of the preparer, the perfect copies of an unknown atomic entangled state can be produced.
基金supported by the National Natural Science Foundation of China under Grant No.10704011the Research Programs of the Educational Office of Liaoning Province under Grant No.2008006
文摘The sender shares six-particle maximally entangled states as quantum channel with the receiver. If the quantum channel is secure, the sender performs projective measurements and tells the measurement outcome to the receiver. The receiver performs the unitary transformations and makes projective measurements on his particles to obtain the secret information. Using teleportation, the transmission of three-qubit secret information can be completed in each quantum channel