Microscopic theory of quantum optical effects in semiconductor nanostructures

近年来，在量子光学和半导体物理这两个领域取得了很大的进展。先进的量子电动力学理论现在在描述原子系统与量子化光场的相互作用方面非常成功，其中原子之间的相互作用只起很小的作用。另一方面，半导体物理通常是由载流子之间的库仑相互作用主导的。因此，先进的半导体理论关注于费米子多体效应的正确描述，而电磁相互作用则局限于经典场。目前项目的主要目标是结合量子光学和半导体物理学的方法，发展一个包括强相互作用载流子之间的多体相关效应以及与量子化光场的耦合的理论。选择密度矩阵方法，推导出耦合载波-光子-声子系统的运动方程，并将所得层次截断为相关的期望值。计算了可直接用于实验测量的光子相关。在此基础上，我们计划研究半导体在相干和非相干激励条件下发射的光的光子统计。更具体地说，将研究相干和非相干激子种群的存在对光发射的影响，并将重点放在纠缠光子态的产生上。本研究小组与实验结果的密切比较对于检查我们理论的预测和激发详细的研究课题至关重要。

In the two fields of quantum optics and semiconductor physics much progress has been made during the last years. Advanced quantum electrodynamics theories are now very successful in the description of the interaction of atomic systems with the quantized light field where the interaction between the atoms plays only a minor role. On the other hand, semiconductor physics is usually dominated by the Coulomb interaction between the carriers. Therefore, advanced semiconductor theories focus on the correct description of the Fermionic many-body effects while the electro-magnetic interaction is limited to classical fields. The main goal of the current project is to combine the methods of quantum optics and semiconductor physics and develop a theory that includes the many-body correlation effects between the strongly interacting carriers as well as the coupling to a quantized light field. Choosing a density matrix approach, we derive the equations of motion for the coupled carrier-photon-phonon system and truncate the resulting hierarchy to the relevant expectation values. Photonic correlations are computed which are directly accessible in experimental measurements. Based on those, we plan to investigate the photon statistics of light emitted from semiconductors under coherent and incoherent excitation conditions. More particularly, the effect of the presence of coherent and incoherent exciton populations on the light emission shall be investigated and the creation of entangled photon states shall be focused on. The close comparison to experimental results within this research group will be vital to check the predictions of our theory and to stimulate the detailed research topics.