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

该项目的目标是研究超快激光脉冲对电子通过连接到两个电子库的单分子输运的可能影响。到目前为止，主要从理论上研究了单色激光场的影响。由于必要设置的复杂性，实验上甚至显示更少。用于本研究的理论基础是一个密度矩阵形式主义，其中整个系统被划分为一个相关的部分，即单分子和费米水库模仿的铅。所采用的量子主方程包含了与时间相关的激光场的相互作用非微扰，是有效的，在低温和弱分子铅耦合。在以前的工作中，短激光脉冲的影响下的电流的表达式已被推导和测试。这种方法有许多扩展的可能性，并可以指向可能的实验实现的电流控制通过分子线的超快激光脉冲。因此，我们要结合联合收割机已经存在的形式主义与最优控制理论，包括电子相关和耦合到热浴描述弛豫过程。此外，我们希望通过与从头算模拟密切联系来改进哈密顿量，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.