We present a quantum ranging protocol that overcomes photon-loss limitations using optimized partially frequencyentangled states.By establishing the fundamental relationship between the degree of entanglement,channel ...We present a quantum ranging protocol that overcomes photon-loss limitations using optimized partially frequencyentangled states.By establishing the fundamental relationship between the degree of entanglement,channel transmission efficiency and measurement precision,we demonstrate superclassical timing resolution in both lossless and lossy regimes.Theoretical analysis and numerical simulations reveal that,under a lossless channel,the precision gain increases with the degree of entanglement,approaching the Heisenberg limit.Importantly,in lossy channels,the precision gain is significantly influenced by both the channel transmission efficiency and the degree of entanglement.For transmission efficiencies above50%,the proposed method provides up to 1.5 times the precision gain of classical methods when entanglement parameters are optimized.Moreover,by optimizing intra-group and inter-group covariances in the multi-structured entangled state,we achieve substantial precision gains even at low transmission efficiencies(~30%),demonstrating its robustness against loss.This study resolves the critical trade-off between entanglement-enhanced precision and loss-induced information degradation.Future implementation could extend to satellite-based quantum positioning,remote sensing,quantum illumination,and other fields that require high-precision ranging in lossy environments.The protocol establishes a universal framework for loss-tolerant quantum metrology,advancing the practical deployment of quantum-enhanced sensing in real-world applications.展开更多
We propose a quantum-enhanced metrological scheme utilizing unbalanced entangled coherent states(ECSs) generated by passing a coherent state and a coherent state superposition through an unbalanced beam splitter(BS). ...We propose a quantum-enhanced metrological scheme utilizing unbalanced entangled coherent states(ECSs) generated by passing a coherent state and a coherent state superposition through an unbalanced beam splitter(BS). We identify the optimal phase sensitivity of this scheme by maximizing the quantum Fisher information(QFI) with respect to the BS transmission ratio. Our scheme outperforms the conventional scheme with a balanced BS, particularly in the presence of single-mode photon loss. Notably, our scheme retains quantum advantage in phase sensitivity in the limit of high photon intensity, where the balanced scheme offers no advantage over the classical strategy.展开更多
We investigate the dynamics of entanglement for a two-parameter class of states in a hybrid qubit-qutrit system under the influence of various dissipative channels. Our results show that entanglement sudden death （ES...We investigate the dynamics of entanglement for a two-parameter class of states in a hybrid qubit-qutrit system under the influence of various dissipative channels. Our results show that entanglement sudden death （ESD） is a general phenomenon and it usually takes place in a qubit-qutrit system interacting with various noisy channels, not only the ease with dephasing and depolarizing channels observed by others. ESD can only be avoided for some initially entangled states under some particular noisy channels. Moreover, the environment affects the entanglement and the coherence of the system in very different ways.展开更多
We propose a scheme for probabilistic teleportation of an unknown two-particle state with a four-particle pure entangled state and positive operator valued measure （POVM）. In this scheme the teleportation of an unkn...We propose a scheme for probabilistic teleportation of an unknown two-particle state with a four-particle pure entangled state and positive operator valued measure （POVM）. In this scheme the teleportation of an unknown two-particle state can be realized with certain probability by performing two Bell state measurements, a proper POVM and a unitary transformation.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
The proposals on entanglement diversion and quantum teleportation of entangled coherent states are presented. In these proposals, the entanglement between two coherent states, ｜α〉 and ｜-α〉, with the same amplitu...The proposals on entanglement diversion and quantum teleportation of entangled coherent states are presented. In these proposals, the entanglement between two coherent states, ｜α〉 and ｜-α〉, with the same amplitude but a phase difference of π is utilized as a quantum channel. The processes of the entanglement diversion and the teleportation are achieved by using the 50/50 symmctric beam splitters, the phase shifters and the photodetectors with the help of classical information.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
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
Recently, Liu et al. [Commun. Theor. Phys. 57(2012) 583] proposed a quantum private comparison protocol based on entanglement swapping of Bell states, which aims to securely compare the equality of two participants...Recently, Liu et al. [Commun. Theor. Phys. 57(2012) 583] proposed a quantum private comparison protocol based on entanglement swapping of Bell states, which aims to securely compare the equality of two participants' information with the help of a semi-honest third party(TP). However, the present study points out there is a fatal loophole in Liu et al.'s protocol, and TP can make Bell-basis measurement to know all the participants' secret inputs without being detected. To fix the problem, a simple solution, which uses one-time eavesdropper checking with decoy photons instead of twice eavesdropper checking with Bell states, is demonstrated. Compared with the original protocol,it not only reduces the Bell states consumption but also simplifies the protocol steps.展开更多
In this paper,we first re-examine the previous protocol of controlled quantum secure direct communication of Zhang et al.’s scheme,which was found insecure under two kinds of attacks,fake entangled particles attack a...In this paper,we first re-examine the previous protocol of controlled quantum secure direct communication of Zhang et al.’s scheme,which was found insecure under two kinds of attacks,fake entangled particles attack and disentanglement attack.Then,by changing the party of the preparation of cluster states and using unitary operations,we present an improved protocol which can avoid these two kinds of attacks.Moreover,the protocol is proposed using the three-qubit partially entangled set of states.It is more efficient by only using three particles rather than four or even more to transmit one bit secret information.Given our using state is much easier to prepare for multiqubit states and our protocol needs less measurement resource,it makes this protocol more convenient from an applied point of view.展开更多
This paper presents a scheme for probabilistic teleportation of an arbitrary GHZ-class state with a pure entangled two-particle quantum channel. The sender Alice first teleports the coefficients of the unknown state t...This paper presents a scheme for probabilistic teleportation of an arbitrary GHZ-class state with a pure entangled two-particle quantum channel. The sender Alice first teleports the coefficients of the unknown state to the receiver Bob, and then Bob reconstructs the state with an auxiliary particle and some unitary operations if the teleportation succeeds. This scheme has the advantage of transmitting much less particles for teleporting an arbitrary GHZ-class state than others. Moreover, it discusses the application of this scheme in quantum state sharing.展开更多
We present a theoretical scheme for perfect teleportation of an unknown multipartite two-level state by a single EPR （Einstein-Podolsky-Rosen） pair, and then generalize it to multilevel, i.e., an N-quNit state can b...We present a theoretical scheme for perfect teleportation of an unknown multipartite two-level state by a single EPR （Einstein-Podolsky-Rosen） pair, and then generalize it to multilevel, i.e., an N-quNit state can be teleported by a single quNit entangled pair, with additional local unitary operations. The feature of the scheme is that teleporting a multipartite state with a reduced amount of entanglement costs less classical bits.展开更多
We propose a most simple and experimentally feasible scheme for teleporting unknown atomic entangled states in driven cavity quantum electrodynamics （QED）. In our scheme, the joint Bell-state measurement （BSM） is ...We propose a most simple and experimentally feasible scheme for teleporting unknown atomic entangled states in driven cavity quantum electrodynamics （QED）. In our scheme, the joint Bell-state measurement （BSM） is not required, and the successful probability can reach 1.0. Furthermore, the scheme is insensitive to the cavity decay and the thermal field.展开更多
The field entropy can be regarded as a measurement of the degree of entanglement between the light field and the atoms of a system which is composed of two-level atoms initially in an entangled state interacting with ...The field entropy can be regarded as a measurement of the degree of entanglement between the light field and the atoms of a system which is composed of two-level atoms initially in an entangled state interacting with the Schroedinger cat state. The influences of the strength of light field and the phase angle between the two coherent states on the field entropy are discussed by using numerical calculations. The result shows that when the strength of light field is large enough the field entropy is not zero and the degrees of entanglement between the atoms and the three different states of the light fields are equal. When the strength of the light field is small, the degree of entanglement is maximum in a system of the two entangled atoms interacting with an odd coherent state; it is intermediate for a system of the two entangled atoms interacting with the Yurke-Stoler coherent state, and it is minimum in a system of the two entangled atoms interacting with an even coherent state.展开更多
In this paper, two schemes for teleporting an unknown four-particle entangled W state is proposed. In the first scheme, two partial entangled four-particle states are used as quantum channels, while in the second sche...In this paper, two schemes for teleporting an unknown four-particle entangled W state is proposed. In the first scheme, two partial entangled four-particle states are used as quantum channels, while in the second scheme,four non-maximally entangled particle pairs are considered as quantum channels. It is shown that the teleportation can be successfully realized with certain probability, for both schemes, if a receiver adopts some appropriate unitary transformations. It is also shown that the successful probabilities of these two schemes are different.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 present a controlled secure quantum dialogue protocol using a non-maximally （pure） entangled Greenberger-Horne-Zeibinger （GHZ） states at first, and then discuss the requirements for a real quantum dialogue. We ...We present a controlled secure quantum dialogue protocol using a non-maximally （pure） entangled Greenberger-Horne-Zeibinger （GHZ） states at first, and then discuss the requirements for a real quantum dialogue. We show that the authorized two users can exchange their secret messages after purifying the non-maximally entangled GHZ states quantum channel unconditionally securely and simultaneously under the control of a third party.展开更多
In this paper, we propose a scheme for transferring an unknown atomic entangled state via cavity quantum electrodynamics （QED）. This scheme, which has a successful probability of 100 percent, does not require Bell-s...In this paper, we propose a scheme for transferring an unknown atomic entangled state via cavity quantum electrodynamics （QED）. This scheme, which has a successful probability of 100 percent, does not require Bell-state measurement and performing any operations to reconstruct an initial state. Meanwhile, the scheme only involves atomfield interaction with a large detuning and does not require the transfer of quantum information between the atoms and cavity. Thus the scheme is insensitive to the cavity field states and cavity decay. This scheme can also be extended to transfer ring an entangled state of n-atom.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
An alternative scheme to approximately conditionally teleport entangled two-mode cavity state without Bell state measurement in cavity QED is proposed. The scheme is based on the resonant interaction of a ladder-type ...An alternative scheme to approximately conditionally teleport entangled two-mode cavity state without Bell state measurement in cavity QED is proposed. The scheme is based on the resonant interaction of a ladder-type three-level atom with two bimodal cavities. The entangled cavity state is reconstructed with only one atom interacting with the two cavities successively.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.62071363)the Key Research and Development Projects of Shaanxi Province,China(Grant No.2021LLRH-06)。
文摘We present a quantum ranging protocol that overcomes photon-loss limitations using optimized partially frequencyentangled states.By establishing the fundamental relationship between the degree of entanglement,channel transmission efficiency and measurement precision,we demonstrate superclassical timing resolution in both lossless and lossy regimes.Theoretical analysis and numerical simulations reveal that,under a lossless channel,the precision gain increases with the degree of entanglement,approaching the Heisenberg limit.Importantly,in lossy channels,the precision gain is significantly influenced by both the channel transmission efficiency and the degree of entanglement.For transmission efficiencies above50%,the proposed method provides up to 1.5 times the precision gain of classical methods when entanglement parameters are optimized.Moreover,by optimizing intra-group and inter-group covariances in the multi-structured entangled state,we achieve substantial precision gains even at low transmission efficiencies(~30%),demonstrating its robustness against loss.This study resolves the critical trade-off between entanglement-enhanced precision and loss-induced information degradation.Future implementation could extend to satellite-based quantum positioning,remote sensing,quantum illumination,and other fields that require high-precision ranging in lossy environments.The protocol establishes a universal framework for loss-tolerant quantum metrology,advancing the practical deployment of quantum-enhanced sensing in real-world applications.
基金supported by the National Natural Science Foundation of China (Grant No. 12005106)support from the National Natural Science Foundation of China (Grant No. 11974189)+1 种基金support from the National Natural Science Foundation of China (Grant No. 12175106)the Postgraduate Research and Practice Innovation Program of Jiangsu Province (Grant No. JSCX23-0260)。
文摘We propose a quantum-enhanced metrological scheme utilizing unbalanced entangled coherent states(ECSs) generated by passing a coherent state and a coherent state superposition through an unbalanced beam splitter(BS). We identify the optimal phase sensitivity of this scheme by maximizing the quantum Fisher information(QFI) with respect to the BS transmission ratio. Our scheme outperforms the conventional scheme with a balanced BS, particularly in the presence of single-mode photon loss. Notably, our scheme retains quantum advantage in phase sensitivity in the limit of high photon intensity, where the balanced scheme offers no advantage over the classical strategy.
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10974020 and 11174039,NCET-11-0031the Fundamental Research Funds for the Central Universities
文摘We investigate the dynamics of entanglement for a two-parameter class of states in a hybrid qubit-qutrit system under the influence of various dissipative channels. Our results show that entanglement sudden death （ESD） is a general phenomenon and it usually takes place in a qubit-qutrit system interacting with various noisy channels, not only the ease with dephasing and depolarizing channels observed by others. ESD can only be avoided for some initially entangled states under some particular noisy channels. Moreover, the environment affects the entanglement and the coherence of the system in very different ways.
基金Supported by the Hebei Natural Science Foundation of China under Grant Nos A2004000141 and A2005000140, and the Natural Science Foundation of Hebei Normal University.
文摘We propose a scheme for probabilistic teleportation of an unknown two-particle state with a four-particle pure entangled state and positive operator valued measure （POVM）. In this scheme the teleportation of an unknown two-particle state can be realized with certain probability by performing two Bell state measurements, a proper POVM and a unitary transformation.
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.
文摘The proposals on entanglement diversion and quantum teleportation of entangled coherent states are presented. In these proposals, the entanglement between two coherent states, ｜α〉 and ｜-α〉, with the same amplitude but a phase difference of π is utilized as a quantum channel. The processes of the entanglement diversion and the teleportation are achieved by using the 50/50 symmctric beam splitters, the phase shifters and the photodetectors with the help of classical information.
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.
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Supported by the National Nature Science Foundation of China under Grant Nos.61103235,61170321,61373016 and 61373131the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Practice Inovation Trainng Program Projects for the Jiangsu College Students(201310300018Z)
文摘Recently, Liu et al. [Commun. Theor. Phys. 57(2012) 583] proposed a quantum private comparison protocol based on entanglement swapping of Bell states, which aims to securely compare the equality of two participants' information with the help of a semi-honest third party(TP). However, the present study points out there is a fatal loophole in Liu et al.'s protocol, and TP can make Bell-basis measurement to know all the participants' secret inputs without being detected. To fix the problem, a simple solution, which uses one-time eavesdropper checking with decoy photons instead of twice eavesdropper checking with Bell states, is demonstrated. Compared with the original protocol,it not only reduces the Bell states consumption but also simplifies the protocol steps.
基金Project supported by NSFC(Grant Nos.61671087,61272514,61170272,61003287,61571335,61628209)the Fok Ying Tong Education Foundation(Grant No.131067)+2 种基金the National Key R&D Program of China under Grant 2017YFB0802300the Open Foundation of Guizhou Provincial Key Laboratory of Public Big Data(2018BDKFJJ016)Hubei Science Foundation(2016CFA030,2017AAA125)。
文摘In this paper,we first re-examine the previous protocol of controlled quantum secure direct communication of Zhang et al.’s scheme,which was found insecure under two kinds of attacks,fake entangled particles attack and disentanglement attack.Then,by changing the party of the preparation of cluster states and using unitary operations,we present an improved protocol which can avoid these two kinds of attacks.Moreover,the protocol is proposed using the three-qubit partially entangled set of states.It is more efficient by only using three particles rather than four or even more to transmit one bit secret information.Given our using state is much easier to prepare for multiqubit states and our protocol needs less measurement resource,it makes this protocol more convenient from an applied point of view.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10604008 and 10435020） and Beijing Education Committee （Grant No XK100270454）.
文摘This paper presents a scheme for probabilistic teleportation of an arbitrary GHZ-class state with a pure entangled two-particle quantum channel. The sender Alice first teleports the coefficients of the unknown state to the receiver Bob, and then Bob reconstructs the state with an auxiliary particle and some unitary operations if the teleportation succeeds. This scheme has the advantage of transmitting much less particles for teleporting an arbitrary GHZ-class state than others. Moreover, it discusses the application of this scheme in quantum state sharing.
基金The project supported by the Fund from Hunan University of Science and Engineering
文摘We present a theoretical scheme for perfect teleportation of an unknown multipartite two-level state by a single EPR （Einstein-Podolsky-Rosen） pair, and then generalize it to multilevel, i.e., an N-quNit state can be teleported by a single quNit entangled pair, with additional local unitary operations. The feature of the scheme is that teleporting a multipartite state with a reduced amount of entanglement costs less classical bits.
基金Project supported by the National Natural Science Foundation of China （Grant No 10374025）.
文摘We propose a most simple and experimentally feasible scheme for teleporting unknown atomic entangled states in driven cavity quantum electrodynamics （QED）. In our scheme, the joint Bell-state measurement （BSM） is not required, and the successful probability can reach 1.0. Furthermore, the scheme is insensitive to the cavity decay and the thermal field.
文摘The field entropy can be regarded as a measurement of the degree of entanglement between the light field and the atoms of a system which is composed of two-level atoms initially in an entangled state interacting with the Schroedinger cat state. The influences of the strength of light field and the phase angle between the two coherent states on the field entropy are discussed by using numerical calculations. The result shows that when the strength of light field is large enough the field entropy is not zero and the degrees of entanglement between the atoms and the three different states of the light fields are equal. When the strength of the light field is small, the degree of entanglement is maximum in a system of the two entangled atoms interacting with an odd coherent state; it is intermediate for a system of the two entangled atoms interacting with the Yurke-Stoler coherent state, and it is minimum in a system of the two entangled atoms interacting with an even coherent state.
文摘In this paper, two schemes for teleporting an unknown four-particle entangled W state is proposed. In the first scheme, two partial entangled four-particle states are used as quantum channels, while in the second scheme,four non-maximally entangled particle pairs are considered as quantum channels. It is shown that the teleportation can be successfully realized with certain probability, for both schemes, if a receiver adopts some appropriate unitary transformations. It is also shown that the successful probabilities of these two schemes are different.
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The project supported by National Natural Science Foundation of China under Grant No. 10575017
文摘We present a controlled secure quantum dialogue protocol using a non-maximally （pure） entangled Greenberger-Horne-Zeibinger （GHZ） states at first, and then discuss the requirements for a real quantum dialogue. We show that the authorized two users can exchange their secret messages after purifying the non-maximally entangled GHZ states quantum channel unconditionally securely and simultaneously under the control of a third party.
基金Project supported by the National Natural Science Foundation of China （Grant No 10574001）, the Program of the Education Department of Anhui Province, China （Grant No 2004kj029）, and the Program of Fuyang Teachers College, China （Grant No 2005LQ04）.
文摘In this paper, we propose a scheme for transferring an unknown atomic entangled state via cavity quantum electrodynamics （QED）. This scheme, which has a successful probability of 100 percent, does not require Bell-state measurement and performing any operations to reconstruct an initial state. Meanwhile, the scheme only involves atomfield interaction with a large detuning and does not require the transfer of quantum information between the atoms and cavity. Thus the scheme is insensitive to the cavity field states and cavity decay. This scheme can also be extended to transfer ring an entangled state of n-atom.
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）.
基金supported by the National Natural Science Foundation of China (Grant No 10674025)Funds from Key Laboratory of Quantum Information, University of Science and Technology of Chinathe Department Funds of Fuzhou University of China (Grant No 2007-XY-15)
文摘An alternative scheme to approximately conditionally teleport entangled two-mode cavity state without Bell state measurement in cavity QED is proposed. The scheme is based on the resonant interaction of a ladder-type three-level atom with two bimodal cavities. The entangled cavity state is reconstructed with only one atom interacting with the two cavities successively.
