Source approach to quantum systems in atomic and mesoscopic physics

一个宏观而复杂的物理系统并不需要完全的量子力学描述。因此，通常需要结合量子和经典方法。系统的经典部分和量子部分之间的界面可以用源来表示，这些源以物质波的形式发射量子粒子。源的例子是电子注入纳米器件的接触，捕获的冷原子云或化学键的断裂。我提出的研究重点是系统的源描述，其他理论方法受到严重的限制。例如，以前的输运理论很少包括长程势，因为没有可用的微扰展开，并且源的局部化禁止使用平移不变性和周期性边界条件。然而，它主要是影响量子系统中的传播的长程势，并且可以用于高精度实验中对其进行调谐。在我的研究计划中提出的新理论方法提供了计算粒子流分布的方法，并将理论原子物理学的方法与凝聚态理论的方法联合收割机结合起来。应用领域是量子态的精确分析，原子和电子的干涉方法，以及通过纳米结构的介观传输。

A macroscopic and complex physical system does not require an entirely quantum mechanical description. As such, typically a combined quantum and classical approach is needed. The interface between the classical and quantum parts of the system can be expressed in terms of sources, which emit quantum particles in the form of matter waves. Examples of sources are the contacts through which electrons are injected into a nanodevice, trapped clouds of cold atoms, or the breaking of chemical bonds. My research proposed is focused on the source description of systems for which other theoretical approaches suffer from severe limitations. For example, previous theories of transport rarely include long-range potentials because no perturbative expansion is available, and the localization of the source prohibits the use of translational invariance and periodic boundary conditions. However, it are mainly long-range potentials which affect the propagation in the quantum system and can be used to tune it for high-precision experiments. The new theoretical approaches put forward in my research proposal provide ways to calculate particle current distributions and combine methods from theoretical atomic physics with those of condensed matter theory. Areas of applications are the precise analysis of quantum states, interferometric methods for atoms and electrons, and mesoscopic transport through nanostructures.