Toolkit for Characterizing Noisy Quantum Processors and Windows of Quantum Advantage

对于某些计算任务，量子计算机提供了潜在的优势，并且可能比现有的经典计算机具有指数级的加速比。建造大规模功能量子计算机的成功无疑将是计算机技术的一场革命。然而，这些应用中的许多都需要错误率非常低的量子计算机，这些计算机使用量子纠错来容错--这项技术在短期内仍无法用于嘈杂的设备。尽管如此，近期量子处理器可以完成某些任务，但对于目前最好的经典计算机来说，仍然是困难的。要展示量子优势，首先需要开发工具来表征量子门的操作、状态准备和测量，以及相应的误差。该项目将整合这些工具，以简化它们在云量子计算机中的使用。了解噪声和误差还有助于制定缓解策略，以便尽可能多地提取正确的计算。该项目还将使用经典模拟将预期结果与在量子计算机上运行的结果进行比较，并分析展示潜在量子优势的方案。该项目的目标是开发和组装一个用于近期可能产生量子优势的量子信息处理工具包。特别是，PI将设计和集成用于(1)断层扫描工具的噪声门特征、(2)随机基准测试、(3)误差缓解方法的工具。这些将在云量子计算机上的实际运行中进行测试。此外，(4)将发展经典的模拟，例如张量网络方法，用于有噪声的量子电路，以及(5)将评估通过短深度量子电路的量子优势方案。还将探索其他新方案，为展示量子设备相对于经典设备的优势提供替代游乐场。开发一个包括技术方法和软件构建的工具包，将有助于验证中等规模的噪声量子信息处理，并确定引导展示量子优势的参数窗口。该项目还将包括对研究生进行研究活动、演讲和写作技能的培训，以及职业规划方面的指导。它将为本科生和高中生提供一些量子信息科学(QIS)研究的第一手经验。这位PI将与他的同事合作，在物理和天文学系的硕士项目中开发量子信息科学/量子技术轨道。创建这样的QIS跟踪/计划将有助于稳定地培养一支量子智能劳动力队伍，预计未来几十年美国对量子智能劳动力的需求将很高。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。

Quantum computers offer potential advantages and possibly exponential speedup over existing classical computers for certain computational tasks. Success in building large-scale functioning quantum computers will undoubtedly be a revolution in computer technology. However, many of these applications will require quantum computers with very small error rates and which use quantum error corrections for tolerating faults - a technology that is still out of reach for near-term noisy devices. Nevertheless, there are certain tasks that near-term quantum processors can perform but are still difficult for the current best classical computers. The demonstration of a quantum advantage will first require development of tools characterizing the operation of quantum gates, state preparation and measurement, as well as the corresponding errors. This project will integrate these tools to streamline their use in cloud quantum computers. Understanding the noise and errors also helps to devise mitigation strategies so as to extract as much as possible the correct computation. This project will also employ classical simulations to compare the expected outcomes with runs on quantum computers and analyze schemes for demonstrating potential quantum advantages.The goal of this project is to develop and assemble a toolkit for near-term quantum information processing that may yield quantum advantage. In particular, the PI will design and integrate tools for (1) noisy-gate characterization of tomographic tools, (2) randomized benchmarking, (3) error mitigation methods. These will be tested in actual runs on cloud quantum computers. Furthermore, (4) classical simulations will be developed, such as tensor-network methods, for noisy quantum circuits, and (5) schemes for quantum supremacy via short-depth quantum circuits will be assessed. Other new schemes will also be explored that will provide alternative playgrounds for showing the advantages of quantum devices over classical ones. Developing a toolkit that consists of technical approaches and software building will help to verify intermediate-scale noisy quantum information processing and identify windows of parameters guiding towards demonstrating quantum advantage. This project will also involve training of graduate students in research activities, presentation and writing skills, and mentoring in career planning. It will provide undergraduates and high-school students some first-hand experience in quantum information science (QIS) research. The PI will work with his colleagues to develop a quantum information science/quantum technology track in the Master's program in the Department of Physics and Astronomy. Creation of such a QIS track/program will help steadily train a quantum-smart workforce that is projected to be of high demand in the United States in the next few decades.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.