Majorana超导混合体系的输运性质研究

发布时间：2018-01-01 13:40

本文关键词：Majorana超导混合体系的输运性质研究　出处：《河北师范大学》2017年硕士论文　论文类型：学位论文

【摘要】：由于非阿贝尔费米子在拓扑量子计算机中的潜在应用,它吸引了人们的广泛关注。研究发现,一个完全服从非阿贝尔统计的物理实体是零能态的Majorana费米子。为此,人们做了一系列的理论计算和实验去探测Majorana费米子的性质。为了探究Majorana费米子对输运性质的影响,本文利用非平衡格林函数的方法研究了量子点耦合四对Majorana费米子体系的输运性质。为了比较,我们同样计算了没有耦合Majorana费米子时的输运情况。首先,我们研究了在超导-正常混合四端电极下,超导端电流的变化曲线。结果显示:Majorana费米子对超导端电流有一个调制作用。一个有趣的现象是电流随正常端(N2)偏压变化曲线上出现了一个峰,这是Majorana费米子之间干涉作用的结果。随后,我们研究了在超导-正常混合四端电极下,正常端电流的变化曲线。发现N2端电流随相位的变化周期变为4?,对此现象进一步探究得出只要体系中存在Majorana费米子,并且Majorana费米子之间的耦合能不为零,N2端电流就会有4?周期。这或许可以成为检测Majorana费米子的一种方法。最后,为了更好在实验上实现Majorana费米子的检测,我们尝试将下端正常电极(N4)解耦,变为三端电极,计算N2端电流变化周期,发现周期为2?。所以只有在四端电极下才能出现4?周期。
[Abstract]:Due to the potential application of non Abel Fermi Zi in topological quantum computer, it has attracted widespread attention. The study found that a completely obey the non Abel statistics physical entity is zero energy state of Majorana fermions. Therefore, people have done a theoretical calculation and a series of experiments to explore the nature of Majorana. In order to explore the Majorana fermion fermion effect on the transport properties of four coupled quantum dots are studied in this paper on the Majorana fermion system by using nonequilibrium Green's function method of transport properties. For comparison, we also calculated the transport situation without coupling Majorana fermions. The first, we studied in superconducting normal hybrid four terminal electrode, change curve of superconducting terminal current. The results showed that Majorana has a role in the modulation of the fermion superconducting end current. An interesting phenomenon is current with the normal side bias (N2) There is a peak curve, which is the result of interference between Majorana fermions. Subsequently, we studied in superconducting normal hybrid four terminal electrode under the curve of normal terminal current. N2 terminal current changes with the cycle phase is 4?, this phenomenon further concludes that as long as the inquiry system in the presence of Majorana fermions and Majorana coupling between fermions can not zero, there will be 4 N2 end of the current cycle.? this could become a method for detection of Majorana fermions. Finally, in order to achieve better detection of Majorana fermions in experiment, we will try to lower the normal electrode (N4) for decoupling. The three terminal electrode, calculation of N2 end of the current cycle of change, that period is 2?. so only in the four to 4 terminal electrode? Cycle.

【学位授予单位】：河北师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O469

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