Controlling Open Quantum Systems: A challenge for the future of quantum technologies

这个项目的目标是确定量子系统的环境可以在多大程度上被用于通过定制的外部电场进行相干控制。操纵量子系统的能力是量子技术未来应用的基本要求，并已成功地在孤立系统中得到演示。然而，大多数与技术相关的量子系统不能被认为是孤立的，诱导退相干是量子控制的主要障碍。特别是，我们将关注凝聚相系统，其中环境在响应驱动系统动态时显示记忆效应。这种情况被称为非马尔科夫，最近引起了人们的极大兴趣，因为原则上它允许信息从环境回流到系统中。该方案的主要思想是在相干控制的背景下使用这一特殊特征，即回答由特定环境模式引起的记忆效应是否实际上可以增加预定义的控制目标，甚至使特定目标可达，即增加可控性。设想的方法遵循从一般控制理论考虑的路线，通过对现实的非孤立量子系统的建模，到在溶液中半导体量子点和染料分子的实验实现。作为主要成果，我们期待新的和替代的控制方案，这些方案超越了依赖于将系统与其环境解耦或隔离的已知策略，并通过具体地利用与其环境的相互作用，在控制非孤立的量子系统方面提供了新的可能性。该方案依赖于汇集来自不同领域的专家，从最优控制理论的基本方面，开放量子系统的描述，特别是在非马尔可夫动力学的背景下，化学物理和半导体物理的专家用于现实模拟，以及世界领先的激光实验控制小组之一。我们相信，这种方法将使我们能够显著推进目前对开放量子系统控制的基本理解，特别是通过利用非马尔科夫效应，这对许多技术上相关的量子系统具有重要影响，远远超出原子和分子物理领域。

The goal of this project is to identify the extent to which the environment of a quantum system can be actively utilized for coherent control by tailored external electric fields. The ability to manipulate quantum systems is an essential requirement for future applications of quantum technologies, and has been successfully demonstrated for isolated systems. However, most technologically relevant quantum systems cannot be considered isolated, and the induced decoherence is a major obstacle to quantum control. In particular, we will focus on condensed phase systems where the environment shows memory effects when responding to the driven system dynamics. This situation is termed non-Markovian, and has attracted a lot of interest recently, since in principle it allows for a back-flow of information from the environment back into the system. The main idea of the proposal is to use this particular feature in the context of coherent control, i.e. to answer the question if memory effects due to specific environmental modes, which cannot be addressed directly by the control fields, can actually increase a predefined control objective, or even make specific objectives accessible, i.e. increasing the controllability.The approach envisaged follows a line from general control theoretical considerations via the modeling of realistic non-isolated quantum systems to experimental realizations in semiconductor quantum dots and dye molecules in solution. As main outcome we expect novel and alternative control scenarios, which go beyond the known strategies relying on decoupling or isolating the system from its environment, and which offer new possibilities in steering non-isolated quantum systems, by specifically exploiting the interaction with their environment.The proposal relies on bringing together experts from different fields, ranging from the fundamental aspects of optimal control theory, the description of open quantum systems, in particular in the context non-Markovian dynamics, experts in chemical physics and semiconductor physics for realistic simulations, and one of the world leading groups in experimental laser control. We believe that this approach will allow us to significantly advance the current fundamental understanding of the control of open quantum systems, in particular by exploiting non-Markovian effects, with important implications for many technologically relevant quantum systems, well beyond the field of atomic and molecular physics.