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Long distance qubit-qubit coupling in silicon quantum dots

硅量子点中的长距离量子位-量子位耦合

基本信息

批准号：
1937062
负责人：
金额：
--
依托单位：
University College London
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-1937062
关键词：
Long distance qubit coupling silicon

项目摘要

Abstract: I study the interaction between quantum mechanical spins controllably trapped in small regions known as quantum dots at the interfaces of a semiconductor, such as silicon, and and an insulator. Even though the electric field of an electron is spherical, electrons have orientation, the spin. Spins can encode information, which can be controlled with the help of electric and magnetic fields. Electron spins in quantum dots can be studied in cold environments provided by so-called dilution refrigerators, which cool them and their immediate environment down very close to absolute zero. Such cold temperatures are required to differentiate the faint signals transmitted by these tiny particles from the ones caused by inevitably noisy environment. To fully process the information contained in spins, they need to interact with one another in a well-defined manner. I study an interaction which can be seen as an interplay of two facts. First, two electrons repel each other due to both having a charge with the same signature. Second, two electrons with exactly the same energy and orientation cannot occupy exactly the same physical space. In systems where two nearby electrons are trapped, they repeatedly swap their spin orientations with one another. This effect is known as the exchange interaction. It turns out that the outer electrons in a system of three or more quantum dot electrons can also interact via spin exchange. We aim to apply this effect to demonstrate qubit-qubit interactions over distances that are long compared to quantum dot sizes. In particular, we aim to study the controllability and quality of the resulting two-qubit gates. If sufficiently strong and controllable, such and interaction would be a helpful step towards realising scalable qubit processors.

摘要：我研究了半导体（例如硅）和绝缘体界面上被称为量子点的小区域中可控捕获的量子机械自旋之间的相互作用。尽管电子的电场是球形的，但电子也有方向，即自旋。自旋可以编码信息，可以借助电场和磁场进行控制。量子点中的电子自旋可以在所谓的稀释制冷机提供的寒冷环境中进行研究，该制冷机将量子点及其周围环境冷却到非常接近绝对零的水平。需要如此寒冷的温度来区分这些微小颗粒传输的微弱信号与不可避免的嘈杂环境引起的信号。为了充分处理自旋中包含的信息，它们需要以一种明确定义的方式相互交互。我研究的相互作用可以被视为两个事实的相互作用。首先，两个电子由于具有相同特征的电荷而相互排斥。其次，具有完全相同能量和方向的两个电子不能占据完全相同的物理空间。在两个附近的电子被捕获的系统中，它们会反复相互交换自旋方向。这种效应称为交换相互作用。事实证明，三个或更多量子点电子系统中的外层电子也可以通过自旋交换相互作用。我们的目标是应用这种效应来证明量子位与量子位在比量子点尺寸更长的距离上的相互作用。特别是，我们的目标是研究由此产生的两个量子位门的可控性和质量。如果足够强大且可控，这种交互将是实现可扩展量子位处理器的有益步骤。