Mesoscopic superconductor as a ballistic quantum switch.

Several key experiments have revealed a rich variety of vortex structures in mesoscopic superconductors in which only a few quanta of magnetic flux are trapped: these structures are polygon-like vortex 'molecules' and multi-quanta giant vortices. Ginzburg-Landau calculations confirmed second-order phase transitions between the giant vortex states and stable molecule-like configurations. Here we study theoretically the electronic structure and the related phase-coherent transport properties of such mesoscopic superconductor systems. The quasiparticle excitations in the vortices form coherent quantum-mechanical states that offer the possibility of controlling the phase-coherent transport through the sample by changing the number of trapped flux quanta and their configuration. The sample conductance measured in the direction of the applied magnetic field is determined by the transparency of multi-vortex configurations, which form a set of quantum channels. The transmission coefficient for each channel is controlled by multiple Andreev reflections within the vortex cores and at the sample edge. These interference phenomena result in a stepwise behaviour of the conductance as a function of the applied magnetic field, and we propose to exploit this effect to realize a vortex-based quantum switch where the magnetic field plays the role of the gate voltage.     

快电子学的进展

分析了快电子学实验室发展过程中形成的应用、技术和理论三个层次的关系,并简述了这个实验室近年来在电磁场仿真、并行采样和抖动研究方面的研究进展.     

The evolution of fast electronics

This paper analyzes the process from gestation to maturity of fast electronics, describes the three-level relations formed in the development of fast electronics, i.e. that of application, technique and theory, and summarizes in brief the progresses in simulation of electromagnetic fields, high-speed parallel sampling, and research of time jitter. Application results of fast electronics in national economy and national major science projects are also introduced.