We investigate the preparation and the control of entangled states in a system with the two-mode coherent fields interacting with a moving two-level atom via the two-photon transition. We discuss entanglement properti...We investigate the preparation and the control of entangled states in a system with the two-mode coherent fields interacting with a moving two-level atom via the two-photon transition. We discuss entanglement properties between the two-mode coherent fields and a moving two-level atom by using the quantum reduced entropy, and those between the two-mode coherent fields by using the quantum relative entropy. In addition, we examine the influences of the atomic motion and field-mode structure parameter p on the quantum entanglement of the system. Our results show that the period and the duration of the prepared maximal atom-field entangled states and the frequency of maximal two-mode field entangled states can be controlled, and that a sustained entangled state of the two-mode field, which is independent of atomic motion and the evolution time, can be obtained, by choosing appropriately the parameters of atomic motion, field-mode structure, initial state and interaction time of the system.展开更多
Entanglement properties of two-mode squeezed coherent states in the radiation field ＆re investigated according to the entanglement criterion [Phys. Rev. Lett. 84 （2000） 2722]. The dependence of entanglement on sque...Entanglement properties of two-mode squeezed coherent states in the radiation field ＆re investigated according to the entanglement criterion [Phys. Rev. Lett. 84 （2000） 2722]. The dependence of entanglement on squeeze angle and squeeze parameter is discussed. It shows that the system evolves into entangled states and entanglement does not increase persistently with the increase of squeeze angle and squeeze parameter. There only exists a certain squeeze angle in which the entanglement exists continuously.展开更多
Considering two identical two-level atoms interacting with two mode thermal field through a nondegeratetwo-photon process,we study the entanglement dynamics between two atoms when the atomic coherence exists.It showst...Considering two identical two-level atoms interacting with two mode thermal field through a nondegeratetwo-photon process,we study the entanglement dynamics between two atoms when the atomic coherence exists.It showsthat the entanglement is dependent on the initial atomic states,and is greatly enhanced due to atomic coherence ascompared with the case when the atomic coherence is ignored.The results also show that the entanglement can becontrolled by changing the relative phases and the amplitudes of the polarized atoms.展开更多
Based on the quantum information theory, this paper has investigated the entanglement properties of a system which is composed of the two entangled two-level atoms interacting with the two-mode entangled coherent fiel...Based on the quantum information theory, this paper has investigated the entanglement properties of a system which is composed of the two entangled two-level atoms interacting with the two-mode entangled coherent fields. The influences of the strength of light field and the two parameters of entanglement between the two-mode fields on the field entropy and on the negative eigenvalues of partial transposition of density matrix are discussed by using numerical calculations. The result shows that the entanglement properties in a system of a pairwise entangled states can be controlled by appropriately choosing the two parameters of entanglement between the two-mode entangled coherent fields and the strength of two light fields respectively.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 19874020）, the Natural Science Foundation of Hunan Province, China （Grant No 05JJ30004）, and the Scientific Research Fund of Hunan Provincial Education Department, China（Grant No 03c543）.
文摘We investigate the preparation and the control of entangled states in a system with the two-mode coherent fields interacting with a moving two-level atom via the two-photon transition. We discuss entanglement properties between the two-mode coherent fields and a moving two-level atom by using the quantum reduced entropy, and those between the two-mode coherent fields by using the quantum relative entropy. In addition, we examine the influences of the atomic motion and field-mode structure parameter p on the quantum entanglement of the system. Our results show that the period and the duration of the prepared maximal atom-field entangled states and the frequency of maximal two-mode field entangled states can be controlled, and that a sustained entangled state of the two-mode field, which is independent of atomic motion and the evolution time, can be obtained, by choosing appropriately the parameters of atomic motion, field-mode structure, initial state and interaction time of the system.
基金The project supported by National Natural Science Foundation of China under Grant Nos.10174024 and 10474025
文摘Entanglement properties of two-mode squeezed coherent states in the radiation field ＆re investigated according to the entanglement criterion [Phys. Rev. Lett. 84 （2000） 2722]. The dependence of entanglement on squeeze angle and squeeze parameter is discussed. It shows that the system evolves into entangled states and entanglement does not increase persistently with the increase of squeeze angle and squeeze parameter. There only exists a certain squeeze angle in which the entanglement exists continuously.
基金Supported by the Young Scientists Fund of the National Natural Science Foundation of China under Grant No.10905028the Program for Science and Technology Department of Henan Province of China under Grant No.102300410050+1 种基金the Opening Project of Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control (Hunan Normal University),Ministry of Education under Grant No.QSQC1003by the Cultivation Fund of Luoyang Normal College under Grant No.10000854
文摘Considering two identical two-level atoms interacting with two mode thermal field through a nondegeratetwo-photon process,we study the entanglement dynamics between two atoms when the atomic coherence exists.It showsthat the entanglement is dependent on the initial atomic states,and is greatly enhanced due to atomic coherence ascompared with the case when the atomic coherence is ignored.The results also show that the entanglement can becontrolled by changing the relative phases and the amplitudes of the polarized atoms.
基金Project supported by the Higher Education of Hubei Province of China （Grant No Z200522001） and the Natural Science Foundation of Hubei Province of China （Grant No 2006ABA055）.
文摘Based on the quantum information theory, this paper has investigated the entanglement properties of a system which is composed of the two entangled two-level atoms interacting with the two-mode entangled coherent fields. The influences of the strength of light field and the two parameters of entanglement between the two-mode fields on the field entropy and on the negative eigenvalues of partial transposition of density matrix are discussed by using numerical calculations. The result shows that the entanglement properties in a system of a pairwise entangled states can be controlled by appropriately choosing the two parameters of entanglement between the two-mode entangled coherent fields and the strength of two light fields respectively.
