Dynamics of different entanglement measures of two three-level atoms interacting nonlinearly with a single-mode field
Dynamics of different entanglement measures of two three-level atoms interacting nonlinearly with a single-mode field
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DOI：
10.1140/epjp/i2015-15037-1
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发表时间：
2015-03-03
影响因子：
3.4
通讯作者：
Tavassoly, M. K.
中科院分区：
文献类型：
--
作者：
Baghshahi, H. R.;Tavassoly, M. K.
在本文中，我们提出了一个模型，该模型展示了两个相同的Ξ型三能级原子与处于克尔介质包围的光学腔中的单模场发生k光子跃迁相互作用。考虑完全非线性形式，假定单模场、原子 - 场耦合以及克尔介质均为f变形。通过使用绝热消去法，表明所考虑系统的哈密顿量可简化为具有两个二能级原子和f变形斯塔克位移的有效哈密顿量。尽管该系统看似复杂，但在可为原子（其基态和激发态的相干叠加）和场（相干态）准备的初始条件下，整个系统的态矢量的显式形式可通过解析方法获得。然后，通过诸如冯·诺依曼熵、缠结和并发度等适当的度量来评估不同子系统（即“场 - 两个原子”、“原子（场 + 原子）”和“原子 - 原子”）之间的纠缠动力学。此外，详细地数值分析了强度相关耦合、变形克尔介质、失谐参数、变形斯塔克位移以及多光子过程对所考虑的纠缠度量的影响。结果表明，通过适当选择演化参数，可以控制子系统之间的纠缠程度。简而言之，克尔介质极大地降低了所考虑的不同纠缠度量的值，特别是对于双光子跃迁。即使存在所有其他参数时，这种破坏性影响仍然存在。此外，我们发现原子 - 原子纠缠中会出现所谓的纠缠突然死亡和产生现象。
In this paper, we present a model which exhibits two identical Xi-type three-level atoms interacting with a single-mode field with k-photon transition in an optical cavity enclosed by a Kerr medium. Considering full nonlinear formalism, it is assumed that the single-mode field, atom-field coupling and Kerr medium are all f-deformed. By using the adiabatic elimination method, it is shown that, the Hamiltonian of the considered system can be reduced to an effective Hamiltonian with two two-level atoms and f-deformed Stark shift. In spite of the fact that, the system seems to be complicated, under initial conditions which may be prepared for the atoms (coherent superposition of their ground and upper states) and the field (coherent state), the explicit form of the state vector of the entire system is analytically obtained. Then, the entanglement dynamics between different subsystems (i.e. "field-two atoms", "atom(field+atom)" and "atom-atom") are evaluated through appropriate measures like von Neumann entropy, tangle and concurrence. In addition, the effects of intensity-dependent coupling, deformed Kerr medium, detuning parameter, deformed Stark shift and multi-photon process on the considered entanglement measures are numerically analyzed, in detail. It is shown that the degree of entanglement between subsystems can be controlled by selecting the evolved parameters, suitably. Briefly, the Kerr medium highly decreases the amount of different considered measures of entanglement, especially for two-photon transition. This destructive effect preserves even when all other parameters are present, too. Furthermore, we find that the so-called entanglement sudden death and birth can occur in the atom-atom entanglement.