作者机构：
[Tan, HT; Xia, HX; Li, GX] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Tan, HT] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
关键词：
entanglement;Gaussian state;noisy channels
摘要：
The evolution of the entanglement of an initial two-mode squeezed vacuum (TMSV) in correlated noisy channels is investigated. It is shown that the correlated environment is helpful for preserving the entanglement of the initial TMSV. The entanglement period of the initial TMSV depends on the correlation property of the correlated environment.
作者机构：
[Huang, GM; Xin, C; Li, GX] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Huang, GM] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
关键词：
quantum nonlocality;linear entropy;thermal environment;squeezed coherent state
摘要：
The effects of initial field state and thermal environment on quantum nonlocality and linear entropy in an atom–field coupling system are investigated. We found that if the cavity is lossless and the reservoir is in vacuum, the atom–field state can exhibit quantum nonlocality periodically and the linear entropies of the atom and the field also oscillate periodically with a period the same as that of quantum nonlocality. And if the cavity dissipation is very weak and the average photon number of the reservoir is very small, the quantum nonlocality will be lost and the linear entropies of the atom and the field oscillate with a decreasing amplitude. The rapidity of the loss of the quantum nonlocality depends on the amplitude of the initial squeezed coherent state, the cavity damping constant κ and the average photon number N of the thermal reservoir. The stronger the field and the larger the constant κ and the average photon number N could be, the more rapidly the nonlocality decreases.
作者机构：
[Huang, GM; Wu, SP; Li, GX] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Li, GX] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
摘要：
The dynamical behavior of the entanglement and the squeezing in the system of two ions trapped in a lossy optical cavity is discussed, in which the vibrational mode of the first ion is coupled to the cavity field via a linear-mixing interaction and the vibrational mode of the second ion is coupled to the cavity field via an effective parametric interaction, respectively. It is found that when the effective strength r1 of the coupling between the first ion and the cavity field is stronger than the strength r2 of the coupling between the second ion and the cavity field, the motional state of the two ions develops into a robust two-mode mixed Gaussian entangled state and the two-mode squeezing of phonons appears. But the entanglement between the cavity mode and the vibrational mode of the second ion can only happen periodically in a small time range. When r1<r2, only the entanglement between the two vibrational modes appears but the two-mode squeezing does not exist. And the entanglement between the cavity mode and the motional mode of the second ion can also take place in a small time range.
作者机构：
[Li, GX] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.;Free Univ Amsterdam, Div Phys & Astron, NL-1081 HV Amsterdam, Netherlands.
通讯机构：
[Li, GX] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
摘要：
The generation of an entangled state for a pair of two-level atoms embedded in a bad cavity injected with a squeezed vacuum is investigated. The degree of entanglement between the two atoms strongly depends on the mean photon number and the strength of two-photon correlations of the squeezed vacuum, the cavity-induced decay rate of atoms, and the atomic separation.
作者机构：
[Gan, ZW; Zhou, L; Li, GX] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Zhou, L] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
关键词：
量子干涉;三层原子结构;自发辐射;双平板结构;原子物理学
摘要：
We investigate the generation of quantum interference induced by spontaneous emission from two transitions of a V-type three-level atom embedded between two parallel plates (one or both the plates have infinite permeability, i.e. μ → ∞). The result shows that, due to the anisotropy of vacuum, quantum interference still exists although the two dipole matrix elements of the atom are orthogonal to each other. When the atom is located very close to one of the plates, the quantum interference effect is particularly prominent. The strength of quantum interference displays oscillating behaviour with the position of the atom. With the increase of the distance between the plates, the oscillation becomes dense.
作者机构：
[Tan, HT; Wu, SP; Li, GX] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Li, GX] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
摘要：
The time-dependent characteristic function for the vibrational quanta of two ions separately trapped in two cascaded optical cavities is obtained analytically beyond the bad cavity limit, in which the motional mode of the ion in the first cavity is coupled to the cavity field via an effective parametric interaction and that of the ion in the second cavity via a linear-mixing interaction as proposed by Peng and Parkins [Phys. Rev. A 65, 062323 (2002)]. It is found that the two ions develop in a two-mode mixed Gaussian entangled state if there exists a unidirectional coupling from the first cavity to the second one.
作者机构：
[Li, GX] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.;Tongji Univ, Dept Phys, Shanghai 200092, Peoples R China.
通讯机构：
[Li, GX] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
摘要：
The dynamical behavior of entanglement for excitons in two quantum dots placed in two separately single-mode optical cavities driven by an external broadband two-mode squeezed vacuum is studied in the low exciton density regime. It is found that if the field in the two separate cavities is initially prepared in a pure two-mode squeezed vacuum state, the excitons in the two quantum dots can evolve into a pure entangled state only when the dissipation of the cavities and exciton modes is negligible. When the effect of the dissipation is included, the excitons will be in a two-mode Gaussian entangled mixed state whose properties are decided by the externally driven field and the initial field. The dependence of the entanglement property of the excitons in the two quantum dots on the squeezing properties of the fields in the two cavities is also discussed.
作者机构：
[Zhou, L; Li, GX] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Li, GX] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
关键词：
Spontaneous emission;Photonic crystal
摘要：
Spontaneous emission behavior from atoms (or molecules) in one-dimensional photonic crystal with a defect is investigated. Taken all the TE and TM modes into account, the normalized spontaneous emission rate of the atom is calculated as a function of the position of the atom in the crystal. Results for both nonabsorbing dielectric structure and absorbing dielectric structure are presented. With the increase of the thickness of the defect in which the atoms are embedded, the oscillations of the spontaneous emission rate versus the position of the atom become dense and the lifetime distribution becomes narrow and sharp. The PC effect may lead to the coexistence of both accelerated and inhibited decay processes.
作者机构：
[Li, GX] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.;Vrije Univ Amsterdam, Div Phys & Astron, NL-1081 HV Amsterdam, Netherlands.;Tongji Univ, Dept Phys, Shanghai 200092, Peoples R China.
通讯机构：
[Li, GX] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
摘要：
The dynamical behavior of entanglement for excitons in two quantum dots placed in a cavity driven by a broadband squeezed vacuum is studied in the low exciton density regime. It is found that the excitons in two quantum dots can evolve into a pure entangled state only when the dissipation of the cavity and exciton modes is negligible. When the injected field into the cavity is a squeezed vacuum, the excitons will be in a two-mode Gaussian entangled mixed state even in the long time limit. Analytical expressions are derived, showing the dependence of the entanglement property of the excitons in two quantum dots on the squeezing properties of the initial state prepared in the cavity and the strength of two-photon correlations of the squeezed vacuum injected into the cavity.
