Semiconductor electron-nuclear spin qubits with optical access

非技术描述量子信息系统具有经典领域不可能实现的能力。这些系统依靠不同类型的量子比特或量子比特来执行不同的任务。例如，光子可用于量子通信，电子可用于量子计算，核自旋可用于量子存储。一般来说，在不同类型的量子比特之间传输信息是具有挑战性的。这项研究项目将研究一种新兴的量子材料-掺铟氧化锌，它有可能成为光子、电子和核量子比特组合系统的基础。通过在半导体平台中访问核自旋存储器，单量子比特隔离可能导致可扩展的量子网络。这样的网络可以用于量子通信，一种基本安全的通信形式，以及量子计算。此外，我们预计，对捐赠者基本性质的进一步了解将对一大批半导体技术产生影响。该项目将为本科生和学生提供实验量子信息方面的研究培训。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旺盛。技术描述晶体中的缺陷是量子网络应用中最先进的量子比特平台之一。它们可能在一个系统中拥有3种类型的物理量子比特：核自旋、电子自旋和光子，分别适用于量子存储、处理和通信。本论文主要研究了氧化锌半导体衬底中的一种特殊的量子点缺陷--浅施主铟。In：ZnO系统具有将有效的光学接口和电子控制结合在一个可以确定地创建的系统中的长期潜力。为此，本项目的目标是(1)在高纯度的氧化锌中实现单施主隔离的高产额掺杂和(2)控制电子-核自旋界面，使具有第二长存储潜力的量子存储器成为可能。在施主：氧化锌系统中实现了高度均匀的光学跃迁，纵向自旋弛豫时间接近1s，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。在量子技术中利用这种半导体系统仍然存在两个主要挑战：单一施主隔离和核自旋控制。单施主隔离的挑战在于氧化锌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氧化锌的策略，设计了选择性探测这一层的光子学制造，以及单/少数施主的注入。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。在扩大妇女在STEM和量子信息领域的参与方面，PI有过往的记录，这将在该奖项下继续下去。最后，该活动将支持威斯康星大学科学探索者计划，该计划汇集了研究生志愿者、一名小学教师和小学生，在一所经济和种族多元化的第一名西雅图公立学校进行科学和工程实验和活动。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.