马约拉纳群岛的零模式的指数保护
S M Albrecht1, A P Higginbotham1,2, M Madsen1
1Center for Quantum Devices and Station Q Copenhagen, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.
Nature
|March 11, 2016
概括
对于量子计算来说至关重要的Majorana零模式,随着纳米线长度的增加,显示出指数级抑制的能量分裂. 这证实了拓保护,并有助于理解量子编织操作.
科学领域:
- 凝聚物质物理学
- 量子计算
- 纳米技术
背景情况:
- 在容错量子计算机中具有潜在应用的奇特准粒子.
- 这些模式被理论化为展示非阿贝尔统计,通过编织实现拓量子运算.
- 之前的实验已经显示了Majorana模式的特征, 但它们的精确行为和拓保护需要进一步调查.
研究的目的:
- 在"Majorana岛"系统中实验测量近零能量的Majorana模式的能量分裂.
- 研究Majorana模式分裂和纳米线长度之间的关系,评估拓保护.
- 提供关于微不足道到拓的转换和拓保护与模式分离的扩展的见解.
主要方法:
- 采用库伦阻塞光谱技术,对具有表轴的InAs纳米线段进行分析,形成一个超导"Majorana岛".
- 通过改变磁场和纳米线长度来测量Majorana模式的能量分裂.
- 分析了运输特性,包括子间隙状态能量和库伦阻塞导电峰值.
主要成果:
- 随着纳米线长度的增加,观察到能量分裂的指数抑制,这是拓保护的关键指标.
- 对于短的设备,子间隙状态能量与磁场振荡,与混合的马约拉纳模式一致.
- 对于长于一微米的设备,传输通过零能量状态发生,显示均间隔的电导峰值,表明Majorana传输.
结论:
- 结果量化了有限系统中的终端模式分离的拓保护.
- 证明了纳米线长度增加的Majorana模式分裂的指数抑制,证实了理论预测.
- 这些发现支持在"Majorana岛屿"中使用Majorana模式进行拓量子计算,并解释过渡到拓阶段.
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