Current, Noise and Full Counting Statistics in Superconducting Junctions

约瑟夫森效应是超导结的基本性质，它展示了超导的宏观量子方面，同时具有许多应用。基本的运输过程，特别是电流的波动，还没有完全理解。鉴于约瑟夫森接触在技术相关的当前标准和先进概念如量子信息处理中的当前利用，这种情况需要改进。我们的目标是与捷克合作伙伴合作开发一种新的理论方法，使用Keldysh绿色的功能，它允许治疗库仑相互作用和耦合到电磁环境中的超导结的电荷传输。我们证明了我们的方法在几个例子中，从扩散正常金属，二维准相对论石墨烯量子点。通过比较随机方法与微观量子力学处理，我们的目标是更好地理解超导结的电阻转变，这不仅是电流量子化的限制因素，而且也有助于在量子处理中的使用。

The Josephson effects are basic properties of superconducting junctions, which demonstrate the macroscopic quantum aspect of superconductivity and have at the same time numerous applications. The underlying transport processes and - especially the fluctuations of the current - are not fully understood. In view of current utilizations of Josephson contacts in technologically relevant current standards and advanced concept like quantum information processing, this situation needs to be improved. Our goal is to develop in collaboration with Czech partners a novel theoretical approach to the transport of charge in superconducting junctions using Keldysh Green’s functions, which allows to treat Coulomb interaction and the coupling to the electromagnetic environment on the same footing. We demonstrate our method in several examples, ranging from diffusive normal metal, two-dimensional quasirelativistic graphene to quantum dots. By comparing stochastic methods with a microscopic quantum mechanical treatment, we aim at a better understanding of the resistive transition of superconducting junctions, which is not only the limiting factor on the current quantization,but also instrumental for the use in quantum processing.