Nanoelectronic Based Quantum Physics- Technology and Applications.

基于纳米电子的量子物理-技术与应用。

• 批准号: EP/K004077/1
• 负责人: Michael Pepper
• 金额: $ 837.95万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FK004077%2F1
• 关键词: Nanoelectronic; Based; Quantum; Physics; Technology

Electrons flowing through semiconductor devices are of immense importance in modern life. When devices are made sufficiently small, such that one of the dimensions is in the nanometre regime, the quantum nature of the electron comes to the fore and must be considered in detail. Working at very low temperatures reduces the mutual electron-electron scattering and results in the wave nature of electron transport becoming observable over distances which can exceed the size of the device. Experiments using devices which are smaller than the coherence length of the wavefunction, or the distance between impurity scattering events, have allowed observation of a range of quantum effects.In recent years theories have proposed that a "quantum computer" has certain advantages over conventional computers as they allow a massively parallel mode of operation. This is based on quantum principles, thus if two electrons are in a quantum state then their total spin wavefunction reflects the range of possible states that can be present. It is this superposition of states which is the basis of a quantum computer. It is a purely quantum phenomenon and has given rise to concepts such as "Schrodinger's Cat" which exemplify the non-intuitive nature of quantum mechanics. Another property which could give rise to new technological applications is the remarkable entanglement. This purely quantum effect results in two electrons being in the same quantum state and "knowing" about each other's existence, consequently if the spin of one is rotated then the spin of the other is affected despite there being a considerable distance between them.In this work we propose to utilise semiconductor nanostructures to find new quantum effects and combine them to create integrated quantum circuits for practical exploitation. The project integrates theory, semiconductor growth/fabrication and measurements in three different centres, it has as initial targets the design and fabrication of key quantum components forsubsequent integration. A principal component is the Quantum Pump which can transmit controlled numbers of electrons at high frequencies with very high accuracy. This device can be used for the generation of entangled electrons which can then be investigated and put to use. Another component which is of importance is the electronic analogy of the polarising beam splitter in optics, here by using localised electron spins an incoming electron is either transmitted or reflected depending on its spin direction. We also propose to exploit the spin-orbit coupling which allows a spin polarised current to be established in a nanostructure which can then be utilised in a quantum device.It is further proposed to build on the use of an indirect electron interaction mechanism to transmit spin information between different devices. A system which may have novel properties in this regard is the incipient Wigner lattice which can form when a line of electrons is weakly confined and minimisation of the electron-electron repulsion forces the electrons to form two separate rows. Here they can be entangled and constitute a continuous supply of entangled electrons in a manner which is complementary to the pump.New types of quantum components will be developed. They will then be integrated to form an early type of circuit in which quantum effects dominate the properties. It is intended to develop basic quantum processors in particular a CNOT gate in which the spin of an electron is rotated depending on the direction of the spin of another. In addition to these objectives a number of spin-off achievements will have an impact on other fields. For example it will be necessary to develop techniques of measurement of electronic properties at ultra low temperatures, 1 milliKelvin, and the spin polarised currents to be developed will have applications in the important field of spintronics.

流经半导体器件的电子在现代生活中非常重要。当器件制造得足够小，使得其中一个维度处于纳米范围时，电子的量子性质就凸显出来，必须详细考虑。在非常低的温度下工作会减少电子与电子之间的相互散射，并导致电子传输的波动性质在超过器件尺寸的距离上变得可观察到。使用小于波函数相干长度或杂质散射事件之间的距离的设备进行的实验可以观察到一系列量子效应。近年来，理论提出“量子计算机”比传统计算机具有某些优势因为它们允许大规模并行操作模式。这是基于量子原理，因此如果两个电子处于量子态，那么它们的总自旋波函数反映了可能存在的状态范围。正是这种状态的叠加才是量子计算机的基础。它是一种纯粹的量子现象，并产生了诸如“薛定谔的猫”之类的概念，这些概念体现了量子力学的非直观本质。另一个可能带来新技术应用的特性是显着的纠缠。这种纯粹的量子效应导致两个电子处于相同的量子态并且“知道”彼此的存在，因此，如果一个电子的自旋旋转，则另一个电子的自旋就会受到影响，尽管它们之间存在相当大的距离。我们建议利用半导体纳米结构来寻找新的量子效应，并将它们结合起来创建用于实际开发的集成量子电路。该项目将理论、半导体生长/制造和测量集成在三个不同的中心，其初始目标是设计和制造用于后续集成的关键量子组件。主要部件是量子泵，它可以以非常高的精度以高频传输受控数量的电子。该装置可用于产生纠缠电子，然后对其进行研究并投入使用。另一个重要的组成部分是光学中偏振分束器的电子类比，这里通过使用局部电子自旋，入射电子根据其自旋方向被透射或反射。我们还建议利用自旋轨道耦合，允许在纳米结构中建立自旋极化电流，然后将其用于量子器件。进一步建议利用间接电子相互作用机制来传输自旋不同设备之间的信息。在这方面可能具有新颖特性的系统是初始维格纳晶格，当电子线受到弱限制并且电子-电子排斥力最小化迫使电子形成两个单独的行时，可以形成该系统。在这里，它们可以纠缠在一起，并以与泵浦互补的方式构成连续的纠缠电子供应。将开发新型量子组件。然后它们将被集成以形成一种早期类型的电路，其中量子效应占主导地位。它的目的是开发基本的量子处理器，特别是 CNOT 门，其中电子的自旋根据另一个电子的自旋方向进行旋转。除了这些目标之外，许多附带成果也将对其他领域产生影响。例如，需要开发1毫开尔文超低温下的电子特性测量技术，而待开发的自旋极化电流将在自旋电子学的重要领域得到应用。

项目成果

Sensitive Radio-Frequency Measurements of a Quantum Dot by Tuning to Perfect Impedance Matching

• DOI: 10.1103/physrevapplied.5.034011
• 发表时间: 2016-03-24
• 期刊: PHYSICAL REVIEW APPLIED
• 影响因子: 4.6
• 作者: Ares, N.;Schupp, F. J.;Laird, E. A.
• 通讯作者: Laird, E. A.

Entanglement structure of the two-channel Kondo model

• DOI: 10.1103/physrevb.93.081106
• 发表时间: 2016-02-18
• 期刊: PHYSICAL REVIEW B
• 影响因子: 3.7
• 作者: Alkurtass, Bedoor;Bayat, Abolfazl;Le Hur, Karyn
• 通讯作者: Le Hur, Karyn

Non-invasive charge detection in surface-acoustic-wave-defined dynamic quantum dots

表面声波定义的动态量子点中的非侵入式电荷检测

• DOI: 10.1063/1.4966667
• 发表时间: 2016
• 期刊: Applied Physics Letters
• 影响因子: 4
• 作者: Astley M

Self-Assembled Wigner Crystals as Mediators of Spin Currents and Quantum Information.

自组装维格纳晶体作为自旋流和量子信息的中介。

• DOI: 10.1103/physrevlett.115.216804
• 发表时间: 2015
• 期刊: Physical review letters
• 影响因子: 8.6
• 作者: Antonio B

High electron mobility and low noise quantum point contacts in an ultra-shallow all-epitaxial metal gate GaAs/Al x Ga1- x As heterostructure

超浅全外延金属栅GaAs/Al x Ga1- x As异质结构中的高电子迁移率和低噪声量子点接触

• DOI: 10.1063/5.0053816
• 发表时间: 2021
• 期刊: Applied Physics Letters
• 影响因子: 4
• 作者: Ashlea Alava Y