SQAM_Spin Qubits in Artificial Molecules

量子信息技术的一个关键要求是实现量子比特，其中量子信息可以在比处理操作所需的时间长得多的时间尺度上存储和操纵。限制在光学活性半导体量子点内的自旋是非常有前途的候选者，因为它们的上级光学特性，它们可以容易地集成到光电器件中，以及用于量子态初始化、控制和读出的光学技术的可用性。在这里，我们建议研究耦合量子点，所谓的量子点分子（QDM），一种结构，支持高度鲁棒性和可控的多自旋量子比特对的自旋动力学。具体的项目任务包括开发基于光学活性单自旋的新颖和定制的量子硬件（电子或空穴）和双自旋量子位限制在电可控QDM器件中。德国小组通过分子束外延、纳米纤维和光谱学开发了纳米结构生长的最先进技术波兰小组在先进理论和建模（k.p方法、量子光学、开放系统动力学）方面拥有广泛的专业知识。这些互补的能力将被结合起来，以发展一个全面的理解量子DM的自旋动力学，以及自旋与其环境的相互作用，特别是结合外部磁场和电场，可用于控制量子态。了解自旋动力学是至关重要的控制量子信息的固态环境中的损失。因此，该项目的成功实现将使分布式量子相干网络的原型在信息处理和安全通信中的应用成为可能。只有通过在涉及制造，表征和建模的理论-实验反馈回路中工作，才能实现项目目标。因此，拟议的研究需要将两个贡献小组的高度互补能力与世界领先的实验和理论固态物理专业知识和能力相结合。

A key requirement for quantum information technology is the realisation of quantum bits where quantum information can be stored and manipulated on timescales much longer than the time needed for processing operations. Spins confined within optically active semiconductor quantum dots are highly promising candidates for this task due to their superior optical properties, the ease with which they can be integrated into optoelectronic devices and the availability of optical techniques for quantum state initialisation, control and readout. Here, we propose to investigate the dynamics of spins in pairs of coupled quantum dots, so-called quantum dot molecules (QDMs), a structure that supports highly robust and controllable multi-spin qubits. Specific project tasks include the development of novel and tailored quantum hardware based on optically active single spin (electron or hole) and double spin qubits confined to electrically controllable QDM devices.The German group has developed state-of-the-art techniques in nanostructure growth by molecular beam epitaxy, nanofabrication and spectroscopy (photoluminescence, Hahn echo, photon correlations, resonance fluorescence), while the Polish group has extensive expertise in advanced theory and modelling (k.p methods, quantum optics, open system dynamics). These complementary capabilities will be combined to develop a comprehensive understanding of the spin dynamics of QDMs, as well as of the interaction of spins with their environment, in particular in combination with external magnetic and electric fields which can be used to control the quantum states.Understanding the spin dynamics is crucial for controlling the loss of quantum information to the solid-state environment. Thus, the successful realisation of this project will enable prototypes of distributed quantum coherent networks with applications in information processing and secure communication.Reaching the project goals is only possible by working in a theory-experiment feedback loop involving manufacturing, characterisation and modelling. Therefore, the proposed research requires combining the highly complementary capabilities of the two contributing groups with world-leading expertise and capabilities in experimental and theoretical solid-state physics.