Optical decoherence and coherent coupling of excitons in quantum dots embedded in photonic cavities

本计画的目的是研究单量子点与多量子点与光腔强耦合时，光激发（激子）的相干动力学。您的培训和研究将在量子点，量子光学和量子点腔量子电动力学的声子诱导光学退相干的多体理论领域。在本计画中，我们将研究透过光回路中的光共振器，来实现量子点的相干耦合与相干控制。此类量子点扮演着隔离量子位的角色，它们的受控耦合对于量子技术应用至关重要。您将计算耦合到光学腔和波导的量子点中的激子吸收和光致发光，以及它们发射的珀塞尔增强。您将学习声学声子诱导的退相和电子去耦量子点中的Foerster转移的理论基本机制，并考虑声学声子环境。您将使用多体理论的各种方法，包括图表技术，Lindblad耗散子的密度矩阵方法，Trotter分解，该项目是嵌入在一个更大的EPSRC资助的研究活动在物理和天文学的卡迪夫学校，并将受益于与实验研究团队的密切合作，工作在控制长-量子点经由腔的距离相干耦合。将理论与测量的光学数据进行比较，将理解相干耦合的基本机制，并提取实验研究系统的重要参数，用于嵌入复杂量子电路中的QD的预测建模。我们在这一领域的科学卓越性得到了Nature集团期刊Nature Mater上关于这一主题的研究出版物的证实。9，304-308（2010）和Nature Commun. 4：1747（2013），以及最近的理论工作提供了一个长期存在的基本问题的量子点腔系统的声子诱导退相干的精确解决方案：arXiv：1807.10977（2018）.可行性：该项目的工作将是分析和数值方法的平衡组合，将包括以下阶段：（i）研究文献和理论方法，解决入门培训问题（ii）计算量子点的相干耦合和控制，起草研究论文（0.5-2.5年）;撰写论文并在会议上发言（2.5-3.5年）。

This project in theoretical physics aims to study the coherent dynamics of optical excitations (excitons) in single and multiple semiconductor quantum dots (QDs) strongly coupled to photonic cavities. Your training and research will be in the areas of many-body theory of phonon-induced optical decoherence in QDs, quantum optics and QD-cavity quantum electrodynamics. In this project, coherent coupling and coherent control of remote QDs via optical resonators in optical circuits will be investigated. Such QDs play the role of isolated qubits, and their controlled coupling is of paramount importance for quantum technology applications. You will be calculating the excitonic absorption and photoluminescence in QDs coupled to optical cavities and waveguides, as well as the Purcell enhancement of their emission. You will be studying theoretically fundamental mechanisms of the acoustic-phonon induced dephasing and the Foerster transfer in electronically decoupled quantum dots with account for the acoustic-phonon environment. You will be using various methods of many-body theory including diagram techniques, density matrix approach with Lindblad dissipators, Trotter's decomposition, matrix cumulant expansion and so on. The project is embedded in a bigger EPSRC funded research activity at Cardiff School of Physics and Astronomy and will benefit from a close collaboration with an experimental research team working on the controlled long-range coherent coupling of quantum dots via cavities. Comparing theory with measured optical data, fundamental mechanisms of the coherent coupling will be understood and important parameters of the experimentally investigated systems will be extracted for predictive modelling of QDs embedded in complex quantum circuits. Our scientific excellence in this field is confirmed by research publications on this topic in Nature group journals: Nature Mater. 9, 304-308 (2010) and Nature Commun. 4:1747 (2013), as well as by the most recent theoretical work providing an exact solution of a long-standing fundamental problem of the phonon-induced decoherence of the QD-cavity system: arXiv:1807.10977 (2018).Feasibility: The work on the project will be a balanced combination of both analytical and numerical methods and will consist of the following stages: (i) Studying literature and theoretical methods, solving introductory training problems (yr 0-0.5); (ii) Calculating coherent coupling and control of remote QDs, drafting research papers (yr 0.5-2.5); Writing up thesis and presenting at conferences (yr 2.5-3.5).