双量子点与Majorana费米子级联结构中的散粒噪声

Shot Noise in Sequential Coupling Structure of Double Quantum Dots and Majorana Fermions

考虑两个量子点分别与拓扑超导纳米线两端的Majorana费米子串联耦合,利用粒子数表象下的量子主方程,研究其中电子的输运特性.存在Majorana费米子时,稳态电流差随着隧穿率的增大呈非对称分布,电子散粒噪声谱相干振荡,且零频噪声明显增强.当系统耦合强度变化时,散粒噪声进一步揭示了Majorana费米子对体系电荷输运的影响.因此,电流差结合电子散粒噪声可以表征量子点与拓扑超导体混合结构中是否存在Majorana费米子.

This work considers the structure of two quantum dots coupled to Majorana fermions at both ends of topological superconductor nanowire. Based on the method of particle-number resolved master equation,the properties of charge transport through the device are studied. When Majorana fermions coupling exists,the steady-state current difference presents asymmetric distribution with increase of tunneling rate,and the electron shot noise shows coherent oscillations with significant enhancement of zero-frequency noise. When coupling strength of system changes,the shot noise further reveals Majorana fermions ＇ effect on the characteristics of electron transport.Therefore,the current difference and electron shot noise can probe the existence of Majorana fermions in hybrid structure of quantum dots and topological superconductor.