Exploring nanowire structures for quantum information - a route to discoveries and new technological applications

探索量子信息的纳米线结构——发现和新技术应用的途径

• 批准号: RGPIN-2018-05109
• 负责人: Ruda, Harry
• 金额: $ 5.97万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=758267
• 关键词: Exploring; nanowire; structures; quantum; information

Classical computers (CC) use classical physics to encode information in binary bits while quantum computers rely on the laws of quantum mechanics (QM) to process information in qubits qubits may simultaneously be in two states due to superposition, and many such qubits can form strongly correlated systems through entanglement, behaving as a single system. Such QM systems are inherently more powerful than CCs, and with sufficiently large numbers of qubits, can solve problems that are intractable with CCs. The search for a perfect platform that simultaneously satisfies requirements of fast quantum control, long coherence times and scalability to thousands of qubits remains a topic of considerable interest. Recently, a new platform based on semiconductor (S) nanowire (NW) heterostructures (HS) has emerged, with qubits showing the fastest electrical spin manipulation times for single spins in QDs. Moreover, the first signatures of Majorana fermions (MFs), which are their own antiparticles and represent the building blocks for topological qubits, have been very recently reported in such NWs. However, these systems are still in their infancy and typically only function in dilution fridge temperatures. NW HS bring: (a) a virtually unlimited choice of materials for both radial and longitudinal HSs as strain may be relieved by unconfined deformation as they grow, and (b) multiple local metal or superconductor (SC) gates may be defined, together with a global back-gate, to provide scalable qubit systems. This proposal examines NW-based schemes addressing shortcomings of current schemes for a scalable QC platform. MF based qubits, through topological protection, should be virtually immune to environment-based decoherence. However, to host them, ballistic (B) NW HS are key - an area where we have demonstrated control over surface state occupation and backscattering to yield state of the art B-NWs; with sufficient quality B-NWs, long thin NWs can be used to enhance immunity. We propose to harness our recent first reports on proximitized SC with high temperature SCs (HTSC), to potentially bring the technology to near-LN2 temperatures something quite new. Next we will explore scalable systems which can be extended into multi-qubit systems. We will also explore the novel possibility of using HTSC/NW-HS systems for gate controlled radiative emission (and two-photon absorption) of entangled photon pairs at elevated temperatures such devices could provide the means to implement “flying” qubits for scalable quantum processing application. We will also explore an alternative platform for dense qubit registers based on self-assembled electron lattices known as the incipient Wigner lattice. This state with entangled e' (spin antiparallel) pairing, can be explored for its' potential for information transmission, computation and memory.

经典计算机（CC）使用经典物理学将信息编码为二进制比特，而量子计算机则依赖于量子力学（QM）定律来处理量子比特中的信息。由于叠加，量子比特可能同时处于两种状态，许多这样的量子比特可以通过纠缠形成强相关系统，表现为单个系统。这样的QM系统本质上比CC更强大，并且具有足够大数量的量子位，可以解决CC难以解决的问题。寻找一个完美的平台，同时满足快速量子控制，长相干时间和可扩展到数千个量子位的要求仍然是一个相当感兴趣的话题。最近，出现了一种基于半导体（S）纳米线（NW）异质结构（HS）的新平台，其中量子位显示出量子点中单自旋的最快电自旋操纵时间。此外，马约拉纳费米子（MF）的第一个签名，这是他们自己的反粒子，并代表拓扑量子比特的构建模块，最近已经在这样的NW中报道。然而，这些系统仍处于起步阶段，通常仅在稀释冰箱温度下起作用。NW HS带来：（a）用于径向和纵向HS的材料的实际上无限的选择，因为应变可以在它们生长时通过无约束变形来减轻，以及（B）可以限定多个局部金属或超导体（SC）门，连同全局背门，以提供可缩放的量子位系统。该提案探讨了基于NW的方案，解决了可扩展QC平台的当前方案的缺点。基于MF的量子比特，通过拓扑保护，应该几乎不受基于环境的退相干的影响。然而，为了承载它们，弹道（B）NW HS是关键-我们已经证明了对表面态占据和反向散射的控制以产生最先进的B-NW的区域;具有足够质量的B-NW，长而薄的NW可以用于增强免疫力。我们建议利用我们最近关于高温SC（HTSC）邻近SC的第一份报告，有可能将该技术带到接近LN 2的温度，这是一种全新的技术。接下来，我们将探索可扩展到多量子位系统的可扩展系统。我们还将探索在高温下使用HTSC/NW-HS系统进行纠缠光子对的门控辐射发射（和双光子吸收）的新可能性，这些设备可以为可扩展的量子处理应用提供实现“飞行”量子位的手段。我们还将探索一种基于自组装电子晶格的致密量子比特寄存器的替代平台，称为初期维格纳晶格。这种具有纠缠e'（自旋反平行）配对的态，可以探索其在信息传输、计算和存储方面的潜力。