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The important role of high-energy intramolecular vibrational modes for excitation energy transfer in the detuned photosynthetic systems is studied. Based on a basic dimer model which consists of two two-level systems(pigments)coupled to high-energy vibrational modes, we find that the high-energy intramolecular vibrational modes can enhance the energy transfer with new coherent transfer channels being opened when the phonon energy matches the detuning between the two pigments. As a result, the energy can be effectively transferred into the acceptor. The effective Hamiltonian is obtained to reveal the strong coherent energy exchange among the donor, the acceptor, and the high-energy intramolecular.A semi-classical explanation of the phonon-assisted mechanism is also shown. 相似文献
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The phonon-assisted process of energy transfer aiming at exploring the newly emerging frontier between biology and physics is an issue of central interest.This article shows the important role of the intramolecular vibrational modes for excitation energy transfer in the photosynthetic systems.Based on a dimer system consisting of a donor and an acceptor modeled by two two-level systems,in which one of them is coupled to a high-energy vibrational mode,we derive an effective Hamiltonian describing the vibration-assisted coherent energy transfer process in the polaron frame.The effective Hamiltonian reveals in the case that the vibrational mode dynamically matches the energy detuning between the donor and the acceptor,the original detuned energy transfer becomes resonant energy transfer.In addition,the population dynamics and coherence dynamics of the dimer system with and without vibration-assistance are investigated numerically.It is found that,the energy transfer efficiency and the transfer time depend heavily on the interaction strength of the donor and the high-energy vibrational mode,as well as the vibrational frequency.The numerical results also indicate that the initial state and dissipation rate of the vibrational mode have little influence on the dynamics of the dimer system.Results obtained in this article are not only helpful to understand the natural photosynthesis,but also offer an optimal design principle for artificial photosynthesis. 相似文献
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Considering two light beams which are in general single-mode Gaussian states
and incident on input ports of an ideal beam splitter, respectively,
this paper
investigates how separability and entanglement of the output lights depend on
degrees of nonclassicality and purities of the input states. The minimum and
maximum amounts of attainable entanglement in the output state are found. 相似文献
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光合作用激发能传输过程中量子效应的研究大都基于单激发初态假设,该假设能较好地描述人们所关心的部分光合作用系统的初态.但对于不满足上述假设条件的自然及人工光合作用系统,激发过程对系统动力学有不可忽略的影响.本文基于由高斯脉冲激发的多色素分子模型,主要研究了激发脉冲宽度和激发间隔对系统动力学和激发能传输效率的影响.首先,推导了理论上可包含任意数量的色素分子构成的供体系统和受体系统整体演化所满足的动力学方程.之后通过数值模拟展示了激发能传输效率随系统各相关参数变化的关系及相应参数的最优范围.研究发现,在单个脉冲激发供体色素分子的条件下,存在最优脉冲宽度,且脉冲宽度对色素分子数目、耦合强度及退相位速率的最优范围都有调制作用,并分析了该调制作用的产生机制.在两个高斯脉冲依次激发供体色素分子的条件下,存在最优脉冲宽度及脉冲间隔的组合.本文得到的动力学方程可推广到其他形式的激发脉冲,得到的数值结果及优化设计原则对工作在不同光照条件下的人工光合作用系统的优化设计具有参考意义. 相似文献
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In this paper, the effects of quantum and classical correlations on the excitation energy transfer in a three-quasi-spin-pigment system are investigated. We first study the dependence of the energy transfer efficiency on various initial correlations of the donor pigments, and find that the initial concurrence is crucial to the efficiency no matter whether the initial states are pure or mixed. We then demonstrate the dynamics of correlations of the system and observe the appearance of sudden death of quantum correlations in the donor pigments. The relation between the energy transfer efficiency and the dynamics of correlations in the donor pigments is also discussed. 相似文献
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Quantum algorithms provide a more efficient way to solve computational tasks than classical algorithms. We experimentally realize quantum permutation algorithm using light's orbital angular momentum degree of freedom. By exploiting the spatial mode of photons, our scheme provides a more elegant way to understand the principle of quantum permutation algorithm and shows that the high dimension characteristic of light's orbital angular momentum may be useful in quantum algorithms. Our scheme can be extended to higher dimension by introducing more spatial modes and it paves the way to trace the source of quantum speedup. 相似文献
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Energy transfer processes between two aggregates in a coupled chromophoric-pigment(protein)system are studied via the standard master equation approach.Each pigment of the two aggregates is modeled as a two-level system.The excitation energy is assumed to be transferred from the donor aggregate to the acceptor aggregate.The model can be used to theoretically simulate many aspects of light-harvesting complexes(LHCs).By applying the real bio-parameters of photosynthesis,we numerically investigate the efficiency of energy transfer(EET)between the two aggregates in terms of some factors,e.g.,the initial coherence of the donor aggregate,the coupling strengthes between the two aggregates and between different pigments,and the effects of noise from the environment.Our results provide evidence for that the actual numbers of pigments in the chromophoric rings of LHCs should be the optimum parameters for a high EET.We also give a detailed analysis of the effects of noise on the EET. 相似文献
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