使用暗态机理将激发能量长时间囚禁在施受系统中.doc

使用暗态机理将激发能量长时间囚禁在施受
系统中
卢竞1,周兰1,付洪忱2
1
湖南师范大学物理与信息科学学院,长沙 410081
2
深圳大学物理科学与技术学院,深圳 518060
摘要:我们研究施受对系统中能量的量子相干传输问题。施系统与受系统相距为 d、并且存在
偶极相互作用。他们与一个共同的环境发生能量交换。我们将施系统与受系统处理为两个二能
级原子,环境处理为多个简谐振子。施受对系统所呈现的相干或非相干行为完全决定于下面两
个耦合强度大小的比较:偶极相互作用强度、原子与环境的耦合强度。对于在色散关系为线性
的环境中一对全同原子,我们具体的计算了初始时刻施系统被激发后,施受对任意系统处于激
发态的几率,并得到了解析的表达式。由于未使用 Markov 近似,在这个式子中辐射的滞后效
应并记入。我们发现当偶极相互作用强度与原子-环境耦合强度可比拟时,光子可长时间的囚
禁在两全同原子中,这种长时间存储机制是因为存在暗态。
关键词:暗态,滞后时间,协同行为
中图分类号:
Dark state mechanism for long-time transfer of
excitation in a donor-acceptor system
Lu Jing1, Zhou Lan1, Fu Hong-Chen2
1
Department of Physics, Hunan Normal University, Changsha 410081
2
School of Physics Science and Technology, Shenzhen University, Shenzhen 518060
Abstract: We study the quantum coherence transfer of excitations between a donor-acceptor
pair with a fixed distance d apart, mutually interacting with dipolar coupling. The pair is
coupled to mon environment through an exchange interaction. By modeling the pair as
two two-level system (TLS) and the environment as many harmonic oscillators, the coherent
or incoherent behavior of this pair appears on whether the pair’s inter-interaction is stronger
or weaker than their coupling to the environment. Taking the linear expansion of the
environmental frequency, an analytical solution for the probability amplitudes of the pair is
obtained which involves all the retardation times. We found that there is a considerable
trapping of the energy within the pair for a long time due to the strong inhibition of radiative
decay of dark states when two TLSs are half a resonant wavelength apart.
Key words: dark state, retardation time, cooperative behavior
基金项目: the Research Fund for the Doctoral Program of Higher Education (20104306120003)
作者简介: Lu Jing(1977-),male,associate professor,major research direction:quantum physics and quantum infor-
mation.
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0 Introduction
In modern ear, energy is the lifeblood of our society. To avoid depleti