Frontiers in the quantum theory of energy transfer

原子间和分子间能量转移是广泛的生物过程(如光合作用植物)和技术装置(如太阳能电池)的基础。甚至有人提出，植物内部能量转移的高效率依赖于量子效应，但这一点仍然存在争议。虽然能量转移的基本机制在几十年前就已知并被广泛理解，但最近理论、计算和实验物理之间的进展(以及它们之间的综合)导致了可以研究的类似能量转移过程的范围和复杂性的爆炸性增长。这些包括预测和发现相关现象(例如原子间库仑衰变)，利用强电场或磁场进行外部控制的新方法，以及从只考虑两三个原子或分子到考虑大型系综的进展。所有这些都需要发展新的理论方法。例如，一种名为量子电动力学密度泛函理论(QEDFT)的理论可以在原子的量子光学图像(无限小的点状发射体/吸收体)和原子的量子化学图像(原子核周围的电子云)之间架起一座桥梁。这个项目的总体目标是使用这些技术和其他适当的技术来推动原子和分子之间能量转移效率的边界，并应用于太阳能电池、辐射生物学和激发子(类似电子学，但控制分子态的激发，而不是电子的流动)。尤其是后者，是通向当今能源密集型计算机的低功耗版本的一条有希望的途径。这种方法的新颖性是量子光学和量子化学技术的独特结合，这将使我们能够产生以前没有考虑过的中间距离处的能量转移速率和动力学的新结果。该项目还将使用微扰理论的重新公式，以便大幅简化少体能量传递率的分析计算，这将应用于激子设备的设计和表征，如晶体管。这项研究符合EPSRC职权范围内的自然科学领域，特别是光物质相互作用和光学现象。这项研究在提高和控制能源转移效率方面的长期应用也可能与太阳能技术领域保持一致。

Interatomic and intermolecular energy transfer underpins a broad range of biological processes (e.g. photosynthesis plants) as well as technological devices (e.g. solar cells). It has even been suggested that the high efficiency of energy transfer within plants relies on quantum effects, but this remains controversial. While the basic mechanism of energy transfer has been known and broadly understood for a number of decades, recently progress in (and synthesis between) theoretical, computational and experimental physics has led to an explosion in the range and complexity of energy transfer-like processes that can be studied. These include the prediction and discovery of related phenomena (e.g. interatomic Coulombic decay), new methods of external control with strong electric or magnetic fields, and a progression from considering only two or three atoms or molecules to considering large ensembles. All of these have advances have required the development of novel theoretical approaches. For example, a theory called quantum electrodynamical density functional theory (QEDFT) can bridge the gap between the quantum-optical picture of an atom (an infinitesimal point-like emitter/absorber) and the quantum chemical picture of an atom (a cloud of electrons around a nucleus).The overall goal of this project is to use these techniques and others as appropriate to push the boundaries of the efficiency of energy transfer between atoms and molecules, with applications in solar cells, radiation biology and excitonics (the analogue of electronics but controlling excitations of molecular states instead of the flow of electrons). The latter in particular is a promising route to low-power versions of today's energy-intensive computers. The novelty of the methodology is a unique mix of techniques from quantum optics and quantum chemistry, which will allow us to generate new results for the rate and dynamics of the rate of energy transfer at the intermediate distances not previously considered. The project will also use reformulations of perturbation theory in order to massively simplify analytical calculation of the rates of few-body energy transfer, which will be applied to design and characterisation of excitonic devices such as transistors. The research aligns with the Physical Sciences area of EPSRC's remit, in particular with light matter interaction and optical phenomena. The longer-term applications of the research in increasing and controlling the efficiency of energy transfer may also align with the solar technology area.