Environment-assisted quantum transport (ENAQT) is the possibility of an external environment to enhance transport efficiency of quantum particles. This idea has generated much excitement over recent years, especially due to the experimentally motivated possibility of ENAQT in photosynthetic exciton transfer complexes. Many theoretical calculations have shown ENAQT, but the explanations for its origin differ, and a universal explanation has been elusive. Here we demonstrate a universal origin for ENAQT in quantum networks with a dephasing environment, based on a relation between exciton current and occupation within a Markovian open quantum system approach. We show that ENAQT appears due to two competing processes, namely, the tendency of dephasing to make the exciton population uniform, and the formation of an exciton density gradient, defined by the source and the sink. Furthermore, we find a geometric condition on the network for the appearance of ENAQT, relevant to natural and artificial systems.

中文翻译：

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激子转移网络中环境辅助量子传输的普遍起源

环境辅助量子传输（ENAQT）是外部环境增强量子粒子传输效率的可能性。近年来，这个想法引起了极大的兴趣，特别是由于在光合作用激子转移复合物中ENAQT具有实验动机。许多理论计算都显示了ENAQT，但是对它的由来的解释有所不同，而对它的通用解释却难以捉摸。在这里，我们基于马尔可夫开放量子系统方法中激子电流与占有量之间的关系，证明了具有相移环境的量子网络中ENAQT的普遍起源。我们显示ENAQT的出现是由于两个相互竞争的过程，即移相使激子总体趋于均匀的趋势以及激子密度梯度的形成，由源和接收器定义。此外，我们在网络上发现了ENAQT出现的几何条件，与自然系统和人工系统有关。