Controlling Open Quantum Systems: A challenge for future quantum technologies – COQS

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 nonMarkovian, 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. enhancing 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 of 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 embedded in very different environments from new materials to life science structures, well beyond the field of atomic and molecular physics.