Coherent and Incoherent Control in Material Systems

材料系统中的相干和非相干控制

• 批准号: 1465201
• 负责人: Tamar Seideman
• 金额: $ 47.57万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1465201&HistoricalAwards=false
• 关键词: Coherent; Incoherent; Control; Material; Systems

With this award, the Chemical Theory, Models and Computational Method program in the Chemistry division is supporting Dr. Tamar Seideman of Northwestern University to develop and apply new theoretical and computational approaches for controlling the properties of nanoscale devices and thus enhance their functionalities. This research is focused on molecular or nanoscale electronics. In one study, Seideman and coworkers introduce an approach to drive current through junctions with light, rather than with voltage, in a way that circumvents the earlier experienced light-induced damage. A second research direction introduces a much needed approach to understanding transport junctions, which enlists the sensitivity of spectroscopy to accurately characterize the structure and chemical composition of molecular-scale electronics. A third, more ambitious study, introduces a new control concept, namely, quantum optimal environment engineering. Here the Seideman group aims to develop a theory and a numerical method to optimize reaction outcomes using reagents that are less costly than lasers. An application is planned to manipulate charge transfer reactions with a view to enhancing the efficiency of solar cells. The first of these studies builds on the success of previous NSF-supported research, where Seideman introduced an approach to coherent control of transport via semiconductor-based molecular-scale electronics as a route to circumventing the difficulties associated with conventional, metal-based molecular-scale electronics, which were noted in the previous experimental literature. The current research goes beyond her earlier, fully analytical solution, which was restricted to the 1- and 2-site bridge cases and to Markovian dynamics, by developing a numerical method and applying it to explore memory effects and multiple-site dynamics. The second research direction explores current-induced Raman spectroscopy as a route to enlisting the chemical sensitivity of Raman spectra to accurately characterize the structure and chemical composition of molecular-scale junctions, and the transport and current-driven dynamics they exhibit. Also under development is a theory to determine, within a uniform approach, the transport, current-driven dynamics and Raman spectra first for a simple adsorbed diatomic molecule and next for a reduced dimensionality model of rhodamine 6G/silver. The third project relies on recent research that shows that the environment can be configured to steer the quantum system into entangled quantum states with high accuracy, as well as to rapidly switch on and off multiple decay channels with ultrafast time precision. Moreover, these environmental controls can potentially allow steering the system into regions of the Hilbert space that are out of reach of coherent control. Environmental engineering concepts are applied to efficiently transform optically excited donor states into free charge carriers via intermediate higher-lying bridge states, and to suppress the losses caused by charge recombination in the polaron states via effective singlet-to-triplet spin state conversion..

有了这个奖项，化学部的化学理论，模型和计算方法计划正在支持西北大学的Tamar Seideman博士开发和应用新的理论和计算方法来控制纳米器件的性能，从而增强其功能。 这项研究的重点是分子或纳米电子学。 在一项研究中，Seideman及其同事介绍了一种方法，通过光而不是电压驱动电流通过结，以避免早期经历的光诱导损伤。第二个研究方向引入了一种非常需要的方法来理解传输结，该方法利用光谱学的灵敏度来准确表征分子尺度电子器件的结构和化学组成。第三项更雄心勃勃的研究引入了一个新的控制概念，即量子最佳环境工程。在这里，Seideman小组的目标是开发一种理论和数值方法，使用比激光更便宜的试剂来优化反应结果。计划应用程序来操纵电荷转移反应，以提高太阳能电池的效率。这些研究中的第一个建立在以前NSF支持的研究的成功基础上，其中Seideman介绍了一种通过基于半导体的分子尺度电子学来相干控制传输的方法，作为规避与传统的基于金属的分子尺度电子学相关的困难的途径，这些困难在以前的实验文献中已经提到。目前的研究超越了她的早期，完全解析的解决方案，这是限制在1-和2-站点的桥梁的情况下，马尔可夫动力学，通过开发一种数值方法，并将其应用于探索记忆效应和多站点动态。第二个研究方向探索电流诱导的拉曼光谱作为一种途径，争取拉曼光谱的化学灵敏度，以准确地表征分子尺度的结的结构和化学组成，以及它们所表现出的传输和电流驱动的动力学。也正在开发的是一个理论，以确定，在一个统一的方法，运输，电流驱动的动力学和拉曼光谱首先为一个简单的吸附双原子分子，然后为一个降维模型的罗丹明6 G/银。第三个项目依赖于最近的研究，该研究表明，环境可以被配置为以高精度将量子系统引导到纠缠量子态，以及以超快的时间精度快速打开和关闭多个衰变通道。此外，这些环境控制可以潜在地允许将系统引导到希尔伯特空间的区域中，这些区域超出了相干控制的范围。环境工程的概念被应用于有效地转换光学激发施主状态到自由电荷载流子通过中间的高躺桥状态，并抑制所造成的损失，通过有效的单重态到三重态的自旋态转换的极化子状态的电荷复合。