Semiconductor electron-nuclear spin qubits with optical access

量子信息系统具有在经典领域不可能的能力。这些系统依赖于不同类型的量子比特或量子比特来执行不同的任务。例如，光子可以用于量子通信，电子用于量子计算，核自旋用于量子存储器。通常，在不同类型的量子位之间传输信息是具有挑战性的。该研究项目将研究一种新兴的量子材料，铟掺杂氧化锌，有可能作为光子，电子和核量子比特系统的基础。在半导体平台上访问核自旋存储器的单量子位隔离可能会导致可扩展的量子网络。这种网络可以用于量子通信，一种基本安全的通信形式和量子计算。此外，我们期望进一步了解施主的基本性质，以影响大量的半导体技术。该项目将为本科生和学生提供实验量子信息的研究培训。由于行业和政府对量子技术的大量投资，量子劳动力培训目前需求量很大。晶体中的缺陷是量子网络应用中最先进的量子位平台之一。它们可能在一个系统中拥有3种类型的物理量子比特：分别适用于量子存储，处理和通信的核自旋，电子自旋和光子。本研究的重点是一个特别有前途的量子点缺陷，浅铟施主在氧化锌（ZnO）半导体主机。In：ZnO系统具有将有效的光学接口和电子控制联合收割机结合在可以确定性地创建的系统中的长期潜力。为此，该项目的目标是（1）在高纯ZnO中实现单施主隔离的高产率掺杂，以及（2）控制电子-核自旋界面，以实现具有秒长存储潜力的量子存储器。在施主：ZnO体系中实现了高度均匀的光学跃迁、近1 s的纵向自旋弛豫时间、50微秒的量子存储时间、电子自旋量子比特初始化和相干布居俘获。利用这种半导体系统进行量子技术仍然存在两个主要挑战：单施主隔离和核自旋控制。单施主隔离的挑战是ZnO衬底中的高施主密度。在这里，我们采用了一种基于分子束外延生长的超高纯度ZnO、旨在选择性探测该层的光子学制造以及单个/少数供体注入的策略。在核自旋控制方面，该团队将开发实现光学核自旋泵浦、光学检测电子自旋共振和核自旋共振的技术，以访问铟核自旋9/2量子存储器。PI在扩大妇女参与STEM和量子信息方面有着良好的记录，这将在该奖项下继续下去。最后，这项活动将包括支持华盛顿大学科学探索者，它汇集了研究生志愿者，小学教师，和小学生进行科学和工程实验和活动，在经济和种族多元化的标题1西雅图公立学校。这个奖项反映了NSF的法定使命，并已被认为是值得支持，通过评估使用基金会的智力价值和更广泛的影响审查标准。

NON-TECHNICAL DESCRIPTIONQuantum information systems have capabilities not possible in the classical domain. These systems rely on different types of quantum bits, or qubits, to perform different tasks. For example, photons may be used for quantum communications, electrons for quantum calculations and nuclear spins for quantum memories. Generally, it is challenging to transfer information between different types of qubits. This research project will investigate an emerging quantum material, indium-doped zinc oxide, with the potential to serve as the basis for a combined photonic, electronic and nuclear qubit system. Single qubit isolation with access to a nuclear spin memory in a semiconductor platform could lead to scalable quantum networks. Such networks can be utilized for quantum communication, a form of fundamentally secure communication, and quantum computation. In addition, we expect further understanding of the fundamental properties of donors to impact a large set of semiconductor technologies. The project will provide research training in experimental quantum information to undergraduate and students. Quantum workforce training is currently in high demand due to the large industry and government investment in quantum technologies. TECHNICAL DESCRIPTIONDefects in crystals are one of the most advanced qubit platforms for quantum network applications. They may boast 3 types of physical qubits in a single system: nuclear spins, electron spins and photons suitable for quantum memory, processing and communication, respectively. This research focuses on a particular promising quantum point defect, the shallow indium donor in the zinc oxide (ZnO) semiconductor host. The In:ZnO system has the long-term potential to combine an efficient optical interface and electronic control in a system that can be deterministically created. Toward this end, the goal of this project is(1) to realize high yield doping with single donor isolation in high-purity ZnO and (2) control over the electron-nuclear spin interface to enable a quantum memory with potential for second-long storage. Highly homogeneous optical transitions, longitudinal spin-relaxation times approaching 1s, 50 microsecond quantum memory times, electron spin qubit initialization and coherent population trapping have all been realized in the donor:ZnO system. Two primary challenges remain to leverage this semiconductor system for quantum technologies: single donor isolation and nuclear spin control. The challenge in single donor isolation is the high donor density in ZnO substrates. Here, we employ a strategy based on ultra-high purity ZnO grown by molecular beam epitaxy, photonics fabrication designed to selectively probe this layer, and implantation of single/few donors. Toward nuclear spin control, the team will develop techniques to realize optical nuclear spin pumping, optically detected electron spin resonance and nuclear spin resonance to access the indium nuclear spin-9/2 quantum memory. The PI has a track record in broadening the participation of women in STEM and quantum information that will continue under this award. Finally, the activity will include support for the UW Science Explorers, which brings together graduate student volunteers, an elementary-school teacher, and elementary school students to conduct science and engineering experiments and activities at an economically and racially diverse Title 1 Seattle public school.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.