NSF-NSERC: Building a two-qubit controlled phase gate using laterally coupled semiconductor quantum dots

NSF-NSERC：使用横向耦合半导体量子点构建两个量子位控制的相位门

• 批准号: 2317047
• 负责人: Pei-Cheng Ku
• 金额: $ 36.23万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-15 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2317047&HistoricalAwards=false
• 关键词: NSF; NSERC; Building; two; qubit

Quantum bit or qubit is the basic building block for quantum science and information processing. The ability to generate, process, and store qubits establishes the foundation for quantum information science and technologies. This collaborative project aims to investigate the interaction between two qubits in a semiconductor system which has been the technology of choice to this date for information processing, communication, and storage. Semiconductor quantum dots are atom-like man-made structures that have been shown to generate and store qubits efficiently. Moreover, quantum dot qubits can seamlessly interface with light to transmit quantum information over a distance. As a result, there have been tremendous interests in exploring quantum dot qubits as the fundamental building block for a future quantum computing or communication system. One critical yet missing link is the ability to process two quantum dot qubits deterministically. This project aims to fill the technological gap by creating two site-controlled quantum dots in a proximity and exploiting the interaction between them. Positive results of this project not only can advance the knowledge of using a semiconductor system for quantum information science and engineering but also develop highly trained engineers and scientists. Isolated electron spins in semiconductor quantum dots have robust coherence; therefore, they are promising qubit candidates for a solid-state quantum system. Heterostructure quantum dot spins can be easily interfaced with photonic qubits, making them especially attractive for quantum network applications. Significant advances have been made in implementing single-qubit operations in heterostructural quantum dots. Further extension of the ability to a two-qubit gate is crucial to enable quantum computational functionalities, e.g., entanglement swapping in a quantum link and generation of the large-scale entangled cluster state. The proposed research focuses on improving a quantum spin-spin gate in heterostructural quantum dots. While an experimental proof-of-concept two-qubit spin gate has been reported recently in a vertically stacked quantum dot structure. However, the coupling mediated by the exchange interaction between two electron spins is not transient, limiting its applicability to general-purpose computational needs. There are also practical challenges in precisely aligning the energy levels between the two quantum dots, which share a common electrical path. This research aims to eliminate these issues by using laterally positioned quantum dots coupled via long-range and on-demand Coulomb interaction. The proposed study builds upon the recent theoretical demonstration of a spin-spin gate between two laterally positioned nitride semiconductor quantum dots, focusing on pushing the boundary of group III-nitride quantum dot growth to experimentally demonstrate a reliable process to create laterally positioned quantum dot pairs with a varying interdot spacing, a transient Coulomb coupling between the dots, and a controlled phase gate between two electron spins.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

量子位或Qubit是量子科学和信息处理的基本基础。生成，处理和商店Qubits的能力为量子信息科学和技术建立了基础。该协作项目旨在调查半导体系统中两个量子位之间的相互作用，这是该日期的信息处理，通信和存储的日期。半导体量子点是原子状的人造结构，已证明可以有效地产生和存储Qubits。此外，量子点量子位可以与光无缝接口，以在远距离传输量子信息。结果，探索量子点量子位作为未来量子计算或通信系统的基本构建块一直具有巨大的兴趣。一个关键但缺失的链接是能够确定性地处理两个量子点量子。该项目的目的是通过在接近性和利用它们之间的相互作用的情况下创建两个站点控制的量子点来填补技术空白。该项目的积极结果不仅可以提高使用半导体系统进行量子信息科学和工程学的知识，而且还可以发展训练有素的工程师和科学家。半导体量子点中的孤立电子自旋具有强大的连贯性。因此，它们是固态量子系统的有希望的量子候选者。 异质结构量子点可以很容易地与光子Qubits连接，从而使其对量子网络应用特别有吸引力。在异质量子点实施单量操作方面已取得了重大进展。将能力的进一步扩展到两个Quibit Gate对于启用量子计算功能至关重要，例如，在量子链接中纠缠交换和大规模纠缠群集状态的生成。提出的研究重点是改善异质量子点中的量子自旋门。虽然最近在垂直堆叠的量子点结构中报道了实验概念验证两量旋转门。但是，两个电子旋转之间的交换相互作用介导的耦合并不是短暂的，从而将其适用性限制在通用计算需求中。精确地对齐两个量子点之间的能量水平也存在实际挑战，这两个量子点具有共同的电路。这项研究旨在通过使用横向定位的量子点来消除这些问题，并通过远距离和按需库仑相互作用耦合。 The proposed study builds upon the recent theoretical demonstration of a spin-spin gate between two laterally positioned nitride semiconductor quantum dots, focusing on pushing the boundary of group III-nitride quantum dot growth to experimentally demonstrate a reliable process to create laterally positioned quantum dot pairs with a varying interdot spacing, a transient Coulomb coupling between the dots, and a controlled phase gate between two Electron Spins。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响审查标准来评估值得支持。