Effects of time-dependent perturbations on the electron transport through single molecules

这个项目的目标是研究超快激光脉冲对连接到两个电子储存库的单分子的电子传输可能产生的影响。到目前为止，主要从理论上研究了单色激光场的影响。在实验上，由于必要设置的复杂性，显示的情况甚至更少。本研究使用的理论基础是密度矩阵形式，其中整个系统被划分为相关的部分，即模拟引线的单分子和费米子储存库。所采用的量子主方程非微扰地考虑了与含时激光场的相互作用，在低温和弱分子-铅耦合条件下是有效的。在以前的工作中，已经推导出了短激光脉冲影响下的电流表达式并进行了验证。这种方法有许多扩展的可能性，并可能指向通过超快激光脉冲通过分子线控制电流的可能的实验实现。因此，我们希望将已有的形式主义与最优控制理论相结合，包括电子关联和描述驰豫过程的热浴耦合。此外，我们希望通过密切接触从头计算模拟等方法来改进哈密顿量，以更好地描述现实系统。

The goal of this project is to investigate the possible influences which ultra-fast laser pulses can have on the electron transport through single molecules connected to two electron reservoirs. So far mainly the influence of monochromatic laser fields has been studied theoretically. Experimentally even less has been shown due to the complexity of the necessary setup. The theoretical foundation used for the present studies is a density matrix formalism where the full system is partitioned into a relevant part, i.e. the single molecule and fermionic reservoirs mimicking the leads. The employed quantum master equation incorporates the interaction with time-dependent laser fields non-perturbatively and is valid at low temperatures and weak molecule-lead coupling. In previous work an expression for the current under the influence of short laser pulses has been derived and tested. This approach has many extension possibilities and can point towards possible experimental realizations of current control through the molecular wire by ultra-fast laser pulses. Therefore we want to combine the already existing formalism with the optimal control theory, include electron correlation and a coupling to a thermal bath describing relaxation processes. Furthermore we want to improve the Hamiltonian to better describe realistic systems by, among other things, making close contact to ab initio simulations.