Semiconductor quantum wells excited by non-classical states of light: Interplay between photonic quantum correlations and many-body interactions in solid state systems

与原子系统相比，体半导体和纳米结构的光学性质的理论描述明显更复杂，但也更丰富，并且可以通过选择纳米结构几何形状和材料组成来设计，例如，在量子威尔斯中。在原子中，电子态是局域的和离散的，而晶格中原子的周期性排列导致了离域的布洛赫态和晶体的连续电子能带结构。此外，在体半导体和纳米结构如量子威尔斯之间的电子和与其他准粒子如声子的多体相互作用非常强烈地影响它们的性质。这有几个重要的后果，如激子共振，其主导带隙附近的线性光学吸收和多体相关性，例如，双激子效应以及由库仑散射和电子-声子散射引起的退相和弛豫过程显著地改变了光学性质。几十年来，在实验和理论上都非常深入地研究了用经典光场激发半导体和半导体纳米结构。然而，关于与量子光的相互作用的知识却少得多。大多数现有文献集中在发射特性上，例如，通过耦合到真空场波动来描述自发光发射（发光），并且由于量子点（所谓的人造原子，具有离散的受限电子态）作为单光子和纠缠光子对的按需源的应用潜力，特别关注量子点。到目前为止，只有很少的研究存在的半导体与量子光的激发，而相当简单的情况下，考虑。有了这个联合提案，我们计划填补这一空白，并制定一个完全量子化和微观的理论方法，能够准确地描述半导体量子威尔斯与复杂的量子光，特别是明亮的压缩光的共振和近共振相互作用。这种非经典光的特征在于宽的光子数分布、光子之间的强相关性、低于散粒噪声水平的噪声降低以及高阶非零轨道角动量的存在。这种光与半导体的相互作用将为激发动力学带来新的特征，并允许将强量子关联从场子系统转移到电子子系统，反之亦然。计划中的研究将有助于发现由于光子相关性和相互作用子系统的相互影响而产生的半导体结构的新特征，提供控制此类系统的电子传输和特性的可能性，并导致新物理现象及其实验可观察签名的预测。

Compared to atomic systems, the theoretical description of the optical properties of bulk semiconductors and nanostructures is significantly more complex but also much richer and over a wide range designable by the choice of the nanostructure geometry and the material composition, e.g., in quantum wells. Whereas in atoms the electronic states are localized and discrete, the periodic arrangement of atoms in a lattice results in delocalized Bloch states and the continuous electronic band structure of crystals. In addition, in bulk semiconductors and nanostructures like quantum wells many-body interactions among the electrons and with other quasi-particles like phonons very strongly influence their properties. This has several important consequences such as excitonic resonances which dominate the linear optical absorption near the band gap and many-body correlations, e.g., biexcitonic effects and dephasing and relaxation processes resulting from Coulomb scattering and electron-phonon scattering that significantly modify the optical properties.The excitation of semiconductors and semiconductor nanostructures with classical light fields has been studied very intensively for several decades both experimentally and theoretically. However, significantly less knowledge is available on the interaction with quantum light. Most of the existing literature focuses on the emission properties, e.g., the description of spontaneous light emission (luminescence) by the coupling to vacuum field fluctuations and much attention was in particular paid to quantum dots (so-called artificial atoms, with discrete confined electronic states) due to their potential for applications as on-demand sources for single photons and entangled photon pairs. Up to now, only very few studies exist on the excitation of semiconductors with quantum light for which rather simple cases were considered. With this joint proposal we plan to fill this gap and to develop a fully-quantized and microscopic theoretical approach able to accurately describe the resonant and near-resonant interaction of semiconductor quantum wells with complex quantum light, in particular with bright squeezed light. Such non-classical light is characterized by broad photon number distribution, strong correlations between photons, noise reduction below the shot-noise level, and presence of high-order non-zero orbital angular momenta. The interaction of such light with semiconductors will bring new features into the excitation dynamics and allows to transfer strong quantum correlations from the field subsystem to the electronic one and vice versa. The planned investigations will help to discover the novel features of semiconductor structures arising due to photonic correlations and mutual influence of interacting subsystems, give the possibility to control the electronic transport and properties of such systems and lead to predictions of new physical phenomena and their experimentally observable signatures.