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，化学理论，模型和计算方法计划在化学部门支持西北大学的塔玛尔·塞德曼博士开发和应用新的理论和计算方法来控制纳米级设备的性质，从而增强其功能。 这项研究的重点是分子或纳米级电子。 在一项研究中，Seideman及其同事引入了一种方法，以通过光而不是电压来驱动电流，以绕过早期经历的光引起的损坏。第二个研究方向引入了一种急需的方法来理解运输连接的方法，该方法吸引了光谱学的灵敏度，以准确表征分子尺度电子产品的结构和化学组成。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小组旨在开发一种理论和数值方法，以使用比激光较高的试剂优化反应结果。计划采用操作电荷转移反应，以提高太阳能电池的效率。这些研究中的第一项基于先前的NSF支持研究的成功，在该研究中，Seideman引入了一种通过基于半导体的分子尺度电子产品一致控制运输的方法，这是绕过与传统的基于金属的分子尺度电子产品相关的困难的途径，在先前的实验文献中被指出。当前的研究超出了她的早期，完全分析的解决方案，该解决方案仅限于1和2个位点的桥梁情况，以及通过开发数值方法并将其应用于探索记忆效应和多个位点动力学的方法。第二个研究方向探索了电流诱导的拉曼光谱，作为吸引拉曼光谱的化学敏感性的途径，以准确表征分子尺度连接的结构和化学组成，以及它们所表现出的传输和电流驱动的动力学。在开发中也是一种理论，可以在均匀的方法中首先确定传输，电流驱动的动力学和拉曼光谱，用于简单吸附的硅藻分子，然后再用于降低若丹明6G/银的尺寸模型。第三个项目依靠最近的研究表明，可以将环境配置为以高精度将量子系统引导到纠缠量子状态，并以超快时间精度快速打开和关闭多个衰减通道。此外，这些环境控制可能会允许将系统转向无法连贯控制的希尔伯特空间区域。环境工程概念用于通过中间上层的桥梁状态有效地将光学激发的供体状态转化为自由载体，并通过有效的单线到三翼旋转状态转换来抑制极性状态的电荷重组造成的损失。