量子点耦合强度对手性Majorana费米子共振交换的调制  

Chiral Majorana fermions resonance exchange moudulated by quantum dot coupling strength

作　　者：吴海滨 刘迎娣 刘彦军 李金花 刘建军 Wu Hai-Bin;Liu Ying-Di;Liu Yan-Jun;Li Jin-Hua;Liu Jian-Jun(College of Science,Shijiazhuang University,Shijiazhuang 050035,China;College of Physics,Hebei Normal University,Shijiazhuang 050024,China)

机构地区：[1]石家庄学院理学院,石家庄050035 [2]河北师范大学物理学院,石家庄050024

出　　处：《物理学报》2024年第13期64-72,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12274305,12074097);河北省自然科学基金(批准号:A2022106001);河北省教育厅科技计划(批准号:QN2022195)资助的课题。

摘　　要：本文研究了外部量子点耦合作用下,量子点耦合两个手性Majorana费米子体系的共振交换.为了观察两个手性Majorana费米子的共振交换,提出了一种基于量子反常霍尔绝缘体(QAHI)近邻耦合s波超导体的电路.数值计算的结果表明,通过外部量子点耦合强度可以调节手性Majorana费米子的共振透射.如果经历了共振隧穿的一个手性Majorana费米子与另一个量子点或Majorana零能模发生共振耦合,则可以实现与超导相位无关的非阿贝尔编织操作.因此所设计方案为Majorana费米子的非阿贝尔编织操作提供一种新的方式,这些发现可能在拓扑量子计算的实现中具有潜在的应用价值.We study the resonance exchanges of two chiral Majorana fermions in two distinct systems theoretically in this work:one is an isolated Majorana zero mode interacting with complexes formed by two chiral Majorana fermions and a Majorana zero mode,and the other involves isolated quantum dots that are coupled to a system composed of Majorana fermions and a quantum dot.Our research results reveal that both of these coupled systems can facilitate the effective transmissions of the two chiral Majorana fermions asγ1→-γ2andγ2→-γ1,and the resonant tunneling effects in the two systems are equivalent.Therefore,quantum dots can replace Majorana zero modes to achieve resonant tunneling.In order to observe the resonance exchange of two chiral Majorana fermions with the two quantum dots,a circuit based on anomalous quantum Hall insulator proximitycoupled with s-wave superconductor is proposed as shown in figure.The numerical results indicate that the resonant exchange of chiral Majorana fermions can be modulated by the coupling strength between the two quantum dots,and it is particularly noteworthy that the tunneling process is independent of the superconducting phase.If one of the chiral Majorana fermions undergoes resonance coupling with another quantum dot or Majorana zero mode,an additional negative sign is obtained,leading to.After 1!22!1 experiencing two resonance exchange processes,the final result is and,which implies the realization of non-Abelian braiding operations.Our conclusion is that the modulation of coupling strength between two quantum dots can be used to achieve the switch of Majorana fermions braiding-like operation,which is independent of superconducting phase.Therefore,the designed scheme provides a new way for adjusting the braiding-like operation of Majorana fermions.These findings may have potential applications in the realization of topological quantum computers.

关 键 词：拓扑超导体 共振隧穿 Majorana费米子 编织 

分 类 号：O469[理学—凝聚态物理]