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

本项目的目的是研究超高速激光脉冲对连接两个电子库的单分子电子传输的可能影响。迄今为止，对单色激光场的影响主要进行了理论研究。由于必要设置的复杂性，实验结果甚至更少。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一个相关的部分，即单分子和费米子储层模拟引线。所采用的量子主方程包含了与时间相关的激光场的非微扰相互作用，并且在低温和弱分子-铅耦合下有效。在以前的工作中，已经推导出了短激光脉冲作用下的电流表达式并进行了测试。该方法具有许多推广的可能性，并为超高速激光脉冲通过分子线控制电流提供了可能的实验实现。因此，我们希望将现有的形式理论与最优控制理论结合起来，包括电子相关和与描述弛豫过程的热浴的耦合。此外，我们希望通过与从头算模拟的密切接触来改进哈密顿量，以便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.