Expanding the Toolbox for Quantum Control of Atomic Qudits

扩展原子量子控制的工具箱

• 批准号: 1212308
• 负责人: Poul Jessen
• 金额: $ 36.6万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-15 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1212308&HistoricalAwards=false
• 关键词: Expanding; Toolbox; Quantum; Control; Atomic

This project uses the hyperfine degrees of freedom of laser cooled cesium atoms as a testbed on which to develop and test new tools for quantum control and measurement. Qubits and qudits (d-level quantum systems) encoded in atomic ground hyperfine states are especially useful for such work because they provide long coherence times, can be coherently manipulated with radiofrequency and microwave fields, and can be probed weakly or strongly with optical fields. Efforts will be focused on two closely related areas of research. The first concerns control and measurement of quantum systems with complex internal structure, and has as its primary objectives to implement unitary control of qubits and qudits encoded in the 16-dimensional hyperfine ground manifold, to explore methods to prepare arbitrary mixed states and implement completely positive maps, and to improve or develop new protocols for quantum state and process tomography based on weak measurement and augmented by new ideas such as compressed sensing. The second focus area relates to quantum control on real world platforms, and has as its primary goals to improve and extend tools for robust qudit control in inhomogeneously broadened quantum systems, and to apply these to atoms in optical dipole traps and optical nanofiber surface traps. The research is primarily experimental, but numerical simulation and more formal theoretical study will also be undertaken.The field of Quantum Information Science (QIS) is motivated by the promise of transformative approaches to computation, communication, and ultra-precise measurement. It has also inspired new ways of thinking about old problems and unresolved issues in physics, and played a role in quantum simulations that study the real-world applicability of idealized theoretical models. QIS is now pursued in many contexts, including nanofabricated condensed matter systems, cold atoms and ions, linear and nonlinear optical systems, and various hybrids thereof. Though details vary with the physics at hand, one of the most fundamental challenges of QIS is universal: one must prepare the relevant quantum system in a well defined initial state, drive it though a complex evolution, and access the final state through measurement. In doing so, many of the tools developed on one platform can be applied to another. This project will use cold atoms as a testbed for control of quantum systems that have more than two levels. The resulting toolbox is likely to be useful and perhaps essential in the many implementations where carriers of quantum information have complex internal structure. The project will also contribute to the training of future scientists in the highly interdisciplinary field of QIS. Students will be involved in all aspects of the project, including education, research, and the dissemination of results. The project is a cornerstone of the NSF supported Center for Quantum Information and Control, co-located at the University of Arizona College of Optical Science and the University of New Mexico Department of Physics and Astronomy. Weekly video conferencing, an annual research retreat, and joint participation in conferences will enrich the educational experience and strengthen the connections between junior and senior participants at both institutions.

该项目使用激光冷却铯原子的超精细自由度作为测试平台，在此基础上开发和测试用于量子控制和测量的新工具。在原子基超精细态中编码的量子比特和量子比特（d级量子系统）对这种工作特别有用，因为它们提供了很长的相干时间，可以用射频和微波场进行相干操作，并且可以用光场进行弱或强探测。努力将集中在两个密切相关的研究领域。第一个领域涉及具有复杂内部结构的量子系统的控制和测量，其主要目标是实现对16维超精细地形中编码的量子位和量子位的统一控制，探索制备任意混合态和实现完全正映射的方法，以及改进或开发基于弱测量并通过压缩感知等新思想增强的量子态和过程层析成像的新协议。第二个重点领域涉及现实世界平台上的量子控制，其主要目标是改进和扩展非均匀扩展量子系统中鲁棒量子控制的工具，并将这些工具应用于光偶极子陷阱和光纳米纤维表面陷阱中的原子。研究主要是实验，但数值模拟和更正式的理论研究也将进行。量子信息科学（QIS）领域是由计算，通信和超精确测量的变革性方法的承诺所驱动的。它还激发了对物理学中老问题和未解决问题的新思考方式，并在研究理想化理论模型在现实世界中的适用性的量子模拟中发挥了作用。量子信息系统现在被应用于许多领域，包括纳米制造凝聚态系统、冷原子和离子、线性和非线性光学系统，以及它们的各种混合系统。尽管细节因物理学的不同而不同，但QIS最基本的挑战之一是普遍的：人们必须将相关的量子系统准备在一个明确定义的初始状态下，驱动它通过复杂的进化，并通过测量进入最终状态。这样，在一个平台上开发的许多工具可以应用于另一个平台。该项目将使用冷原子作为控制两个以上能级量子系统的试验台。由此产生的工具箱在量子信息载体具有复杂内部结构的许多实现中可能是有用的，也许是必不可少的。该项目还将有助于培养QIS高度跨学科领域的未来科学家。学生将参与项目的各个方面，包括教育、研究和成果的传播。该项目是美国国家科学基金会支持的量子信息与控制中心的基石，该中心位于亚利桑那大学光学科学学院和新墨西哥大学物理与天文学系。每周的视频会议，每年的研究静修，以及共同参加会议，将丰富两所大学的教育经验，并加强两所大学的初级和高级参与者之间的联系。