Farrow Tristan, Vedral Vlatko
1] Atomic & Laser Physics, Clarendon Laboratory, University of Oxford, OX1 3PU, UK [2] Centre for Quantum Technologies, National University of Singapore, Singapore 117543 [3] Oxford Martin School, Old Indian Institute, University of Oxford, OX1 3BD, UK.
Sci Rep. 2014 Jul 1;4:5520. doi: 10.1038/srep05520.
A generic and intuitive model for coherent energy transport in multiple minima systems coupled to a quantum mechanical bath is shown. Using a simple spin-boson system, we illustrate how a generic donor-acceptor system can be brought into resonance using a narrow band of vibrational modes, such that the transfer efficiency of an electron-hole pair (exciton) is made arbitrarily high. Coherent transport phenomena in nature are of renewed interest since the discovery that a photon captured by the light-harvesting complex (LHC) in photosynthetic organisms can be conveyed to a chemical reaction centre with near-perfect efficiency. Classical explanations of the transfer use stochastic diffusion to model the hopping motion of a photo-excited exciton. This accounts inadequately for the speed and efficiency of the energy transfer measured in a series of recent landmark experiments. Taking a quantum mechanical perspective can help capture the salient features of the efficient part of that transfer. To show the versatility of the model, we extend it to a multiple minima system comprising seven-sites, reminiscent of the widely studied Fenna-Matthews-Olson (FMO) light-harvesting complex. We show that an idealised transport model for multiple minima coupled to a narrow-band phonon can transport energy with arbitrarily high efficiency.
展示了一个用于耦合到量子力学热库的多极小值系统中相干能量传输的通用且直观的模型。通过一个简单的自旋 - 玻色子系统，我们说明了如何利用窄带振动模式使一个通用的供体 - 受体系统达到共振，从而使电子 - 空穴对（激子）的转移效率任意提高。自从发现光合生物中的光捕获复合物（LHC）捕获的光子能够以近乎完美的效率传递到化学反应中心以来，自然界中的相干传输现象再次引起了人们的兴趣。传统的转移解释使用随机扩散来模拟光激发激子的跳跃运动。这对于在最近一系列具有里程碑意义的实验中测量的能量转移的速度和效率解释不足。从量子力学的角度来看有助于捕捉该转移有效部分的显著特征。为了展示该模型的通用性，我们将其扩展到一个包含七个位点的多极小值系统，这让人联想到广泛研究的费纳 - 马修斯 - 奥尔森（FMO）光捕获复合物。我们表明，一个耦合到窄带声子的多极小值理想化传输模型能够以任意高的效率传输能量。
