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: $ 2.99万
• 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: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=663881
• 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)使用经典物理来编码信息，而量子计算机则依靠量子力学(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个状态，并且许多这样的量子比特可以通过纠缠形成强关联的系统，表现为单个系统。这样的QM系统天生就比CCS更强大，并且拥有足够多的量子比特，可以解决CCS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比特的要求，仍然是一个相当感兴趣的话题。最近，一种基于半导体(S)纳米线(NW)异质结构(HS)的新平台出现了，量子比特显示了量子点中单个自旋的最快电自旋操纵时间。此外，马约拉纳费米子(MFS)的第一个签名最近在这样的NWS上被报道，它是它们自己的反粒子，代表着拓扑量子比特的构建块。然而，这些系统仍处于初级阶段，通常只在稀释冰箱的温度下运行。NW HS带来：(A)径向和纵向HSS的几乎无限的材料选择，因为随着它们的生长，无约束变形可以缓解它们的应变，以及(B)可以定义多个局部金属或超导(SC)门，连同全局后门，以提供可扩展的量子比特系统。本提案研究了基于NW的方案，以解决当前方案的缺陷，以实现可扩展的QC平台。基于MF的量子比特，通过拓扑保护，实际上应该不受基于环境的退相干的影响。然而，要承载它们，弹道(B)NW HS是关键--在这一领域，我们已经展示了对表面态占据和后向散射的控制，以产生最先进的B-NW；有了足够高质量的B-NW，可以使用细长的NW来增强免疫力。我们建议利用我们最近关于高温SC(HTSC)的第一份报告，潜在地将该技术带到接近LN2的温度--这是一种相当新的东西。接下来，我们将探索可扩展为多量子比特系统的可扩展系统。我们还将探索利用HTSC/NW-HS系统在高温下对纠缠光子对进行门控辐射发射(和双光子吸收)的新可能性-这种设备可以为可扩展的量子处理应用提供实现“飞行”量子比特的手段。我们还将探索一种基于自组装电子晶格的密集量子比特寄存器的替代平台，称为初始维格纳晶格。这种具有纠缠e‘(自旋反平行)配对的状态可以用来研究它在信息传输、计算和存储方面的潜力。