Majorana束缚态体系的输运质-凝聚态物理专业毕业论文.docx

用来探测Majorana束缚态。此外，我们还研究了体系的电流相位关系。 关键词：Majorana束缚态光子辅助隧穿约瑟夫森电流 IV 万方数据  Abstract In recent years，Majorana bound states，obeying an exotic form of quantum statistics called non-Abelian statistics，can be used as the simplest platform for realizing topological quantum information processing．These properties have attracted increasing attention．In this paper,we focus on the properties of the Majorana bound states and the methods to probe the existence of the Majorana bound states． Firstly,to understand the effect of photon assisted tunneling(PAT)，the effect of an ac electric field on quantum transport properties in a system of three quantum dots， two of which are connected in parallel，while the third is coupled to one of the other two，is investigated theoretically．Based on the Keldysh nonequilibrium Green’S function method，the spm-dependent current，occupation number,and spin accumulation Can be obtained in our model．An external magnetic flux，Rashba spiIl-orbit-coupling(soc)，and intradot Coulomb interactions are considered．The magnitude of the spin-dependent average current and the positions of the PAT peaks can be accurately controlled and manipulated by simply varying the strength of the coupling and the frequency of the ac field．A particularly interesting result is the observation of a new kind of PAT peak and a multiple—PAT effect that can be generated and controlled by the coupling between the quantum dots．In addition，the spin occupation number and spin accumulation can be well controlled by the Rashba SOC and the magnetic flux Secondly,Employing the Keldysh Nonequilibrium Green’S function method，we investigate time—dependent transport through a topological superconductor with Majorana bound states in the presence of a high frequency microwave field．It is found that Majorana bound states driven by photon-assisted tunneling Can absorb(emit) photons and the resulting photon-assisted tunneling side band peaks can split the Majorana bound state that then appears at n