NSF-BSF: Optical Coherent Control of Quantum Dot Spin for Ultra-Fast Quantum Information Processing

NSF-BSF：用于超快速量子信息处理的量子点旋转的光学相干控制

• 批准号: 1915375
• 负责人: Edo Waks
• 金额: $ 45.49万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1915375&HistoricalAwards=false
• 关键词: NSF; BSF; Optical; Coherent; Control

Among the many choices for solid-state quantum emitters, indium arsenide quantum dots exhibit some of the best optical properties. They emit photons with nearly perfect efficiency and purity. In addition, quantum dots can trap single electrons that act as quantum memories that strongly interact with photons, a key ingredient for long-distance quantum networks. But these spins lose their quantum properties extremely fast because they interact with a large number of nuclear spins that always exist in the natural crystalline structure of the host substrate. In order to improve the quantum properties of these spins and increase the timescales over which they persist requires a better fundamental understanding of spin-nuclear interactions in semiconductors. This improved understanding could directly enable methods to decouple the electrons from the large nuclear spin bath, resulting in orders of magnitude improvements in their coherence lifetime. This program aims to both attain a better understanding of spin nuclear interactions and improve spin lifetimes in semiconductors using a technique called dynamical coherent control. This approach manipulates the spin rapidly to decouple it from noise sources on different timescales. Using this technique, the principal investigator will study the noise properties of spins in a semiconductor host material, and develop new techniques to eliminate them. Success of this program could enable a new generation of chip-integrated quantum devices that can efficiently store and transmit quantum information over long distances. This program is a collaborative NSF-BSF proposal which combines the expertise of the University of Maryland in quantum dot spectroscopy and the Hebrew University in Jerusalem on noise spectroscopy and coherent spin control.To achieve the program goals, the collaborative team will combine state-of-the-art noise spectroscopy and dynamical decoupling with nanophotonic engineering. They will develop a novel optical excitation scheme based on ultra-fast modulation of a narrowband laser to achieve complete spin control along all three axes. Such modulation can be programmed to create nearly unlimited control sequences, thus enabling spin control with significantly greater complexity and opening new possibilities for quantum information processing. They will use this new scheme to perform noise spectroscopy of the quantum dot spin qubit, elucidating the physics underlying its dominant noise sources. Using the physical insight gained from these experiments, they will develop optimized dynamical decoupling sequences that could significantly extend the coherence time of the qubit beyond current state-of-the-art. Coupling these optically active quantum memories to nanophotonic cavities will provide a path to engineer efficient spin-photon interfaces, and achieve large scalability. The ability to control and decouple nuclear spin interactions in III-V semiconductors would provide a qubit system with long-lived coherence properties and nearly pristine quantum emission. Such a system could form the fundamental building block for quantum networks, photonic quantum computers, and quantum sensors. In the III-V semiconductor community, spin dynamics remains a poorly understood area of research with many open questions regarding the dominant noise interactions and fundamental coherence limits. This research will shed light on this poorly understood physics, opening up brand new applications and control tools for spin in III-V semiconductor materials. In addition to the research component, this program will include a strong outreach effort to educate high school students and broaden participation in STEM fields.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.

在固态量子发射体的众多选择中，砷化铟量子点表现出一些最好的光学特性。它们以近乎完美的效率和纯度发射光子。此外，量子点可以捕获单个电子，充当与光子强烈相互作用的量子存储器，这是长距离量子网络的关键组成部分。但是这些自旋失去量子特性的速度非常快，因为它们与大量的核自旋相互作用，而这些核自旋总是存在于宿主基质的自然晶体结构中。为了改善这些自旋的量子特性并增加它们持续存在的时间尺度，需要对半导体中自旋核相互作用有更好的基本理解。这种改进的理解可以直接使电子从大的核自旋浴中解耦，从而使它们的相干寿命得到数量级的提高。该计划旨在更好地理解自旋核相互作用，并利用一种称为动态相干控制的技术提高半导体中的自旋寿命。这种方法可以快速操纵自旋，使其与不同时间尺度上的噪声源分离。利用这项技术，首席研究员将研究半导体宿主材料中自旋的噪声特性，并开发新的技术来消除它们。该计划的成功将使新一代芯片集成量子设备能够有效地存储和长距离传输量子信息。该项目是NSF-BSF的合作提案，结合了马里兰大学在量子点光谱和耶路撒冷希伯来大学在噪声光谱和相干自旋控制方面的专业知识。为了实现项目目标，合作团队将结合最先进的噪声光谱和动态解耦与纳米光子工程。他们将开发一种基于窄带激光超快速调制的新型光激发方案，以实现沿所有三个轴的完全自旋控制。这种调制可以编程来创建几乎无限的控制序列，从而使自旋控制具有更大的复杂性，并为量子信息处理开辟了新的可能性。他们将使用这个新方案来执行量子点自旋量子比特的噪声光谱，阐明其主要噪声源的物理基础。利用从这些实验中获得的物理见解，他们将开发优化的动态解耦序列，这将大大延长量子比特的相干时间，超过当前最先进的技术。将这些光学主动量子存储器耦合到纳米光子腔将为设计有效的自旋光子接口提供一条途径，并实现大的可扩展性。在III-V型半导体中控制和解耦核自旋相互作用的能力将提供一个具有长寿命相干性和几乎原始量子发射的量子比特系统。这样的系统可以构成量子网络、光子量子计算机和量子传感器的基本构建块。在III-V半导体界，自旋动力学仍然是一个知之甚少的研究领域，有许多关于主要噪声相互作用和基本相干限制的开放问题。这项研究将揭示这一鲜为人知的物理学，为III-V半导体材料的自旋开辟全新的应用和控制工具。除了研究部分，该计划还将包括大力推广教育高中生和扩大STEM领域的参与。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

All-Optical Noise Spectroscopy of a Solid-State Spin

固态自旋的全光噪声光谱

• DOI: 10.1021/acs.nanolett.2c04552
• 发表时间: 2023
• 期刊: Nano Letters
• 影响因子: 10.8
• 作者: Farfurnik, Demitry;Singh, Harjot;Luo, Zhouchen;Bracker, Allan S.;Carter, Samuel G.;Pettit, Robert M.;Waks, Edo
• 通讯作者: Waks, Edo

Single-Shot Readout of a Solid-State Spin in a Decoherence-Free Subspace

无退相干子空间中固态自旋的单次读出

• DOI: 10.1103/physrevapplied.15.l031002
• 发表时间: 2021
• 期刊: Physical Review Applied
• 影响因子: 4.6
• 作者: Farfurnik, D.;Pettit, R. M.;Luo, Z.;Waks, E.
• 通讯作者: Waks, E.