FET: Small: Decoding Quantum Error-Correcting Codes for Quantum Computing and Communication

FET：小型：解码量子计算和通信的量子纠错码

• 批准号: 2316713
• 负责人: Todd Brun
• 金额: $ 60万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-12-01 至 2026-11-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2316713&HistoricalAwards=false
• 关键词: FET; Small; Decoding; Quantum; Error

Quantum computers promise to solve many difficult computational tasks that strain the abilities of ordinary (classical) computers, especially in simulating quantum-mechanical systems and finding optimal solutions to a variety of mathematical problems. However, building large-scale quantum computers requires overcoming the challenge of decoherence, or quantum noise. The general answer to this is known: quantum error correction, to achieve fault-tolerant quantum computation. The current generation of noisy, intermediate scale quantum (NISQ) processors are too small and noisy to take real advantage of quantum error correction (QEC), but as they grow in size and improve in quality, this will soon become possible. Fully fault-tolerant quantum computing (FTQC) is very demanding; but some elements of fault-tolerance should be possible in the next few years. This project aims to develop methods of fault-tolerant quantum computation that will be practical in near-term machines. The approach uses quantum teleportation to process quantum bits (qubits) stored in efficient quantum codes that protect them against decoherence. his award will support Ph.D. students working towards their degrees, and will enrich the broad educational efforts at the University of Southern California. These efforts now include not only faculty, postdocs and Ph.D. students, but master's students in the MS program in Quantum Information Science, and a growing number of undergraduate students.This project will build upon an approach based on encoding logical qubits in multi-qubit block codes with high rates. In the very near term it will be possible to use quantum error-detecting codes that encode n–2 logical qubits in n physical qubits, with a universal set of encoded gates. Such a scheme cannot be fully fault-tolerant, but it can be weakly fault-tolerant, able to detect any single fault by a final (or intermediate) measurement and post-select on no error being detected. For small computations this will give an improvement over an unencoded quantum circuit. As qubit counts increase and noise rates diminish, more elements of FTQC can be added until full fault-tolerance is achieved. This project will also tackle the problem of preparing ancilla states, which are the building blocks of teleportation-based FTQC by combining state preparation and verification into a single process, using a combination of flag-based methods and error detection. The investigators will also pursue fast and accurate decoding algorithms for QEC codes that could be used in real time during a quantum computation. This project will develop decoding algorithms via machine learning methods. In addition, the project will explore applications of QEC codes to other problems in quantum information science. TThis 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.

量子计算机有望解决许多困难的计算任务，这些任务限制普通（经典）计算机的能力，尤其是在模拟量子机械系统并找到各种数学问题的最佳解决方案时。但是，构建大规模量子计算机需要克服变质或量子噪声的挑战。这是已知的一般答案：量子误差校正，以实现容忍量的量子计算。当前一代的噪声，中等规模量子（NISQ）处理器太小，噪声无法真正利用量子误差校正（QEC），但是随着它们的大小和质量提高，它们很快就会成为可能。完全容忍故障的量子计算（FTQC）非常苛刻。但是，在未来几年中，应该可能实现某些耐断层量子计算的要素。该项目旨在开发耐故障量子计算的方法，在近期机器中将是实用的。该方法使用量子传送来处理有效的量子代码中存储的量子位（Qubit），以保护它们免受反熔。他的奖项将支持博士学位。学生在学位上工作，并将在南加州大学丰富广泛的教育工作。现在，这些努力不仅包括教职员工，博士后和博士学位。学生，但是量子信息科学的MS计划和越来越多的本科生的硕士学生。该项目将基于一种基于编码逻辑量子的方法以高率的多数块代码进行编码。在短期内，可以使用n – 2的n – 2逻辑Qubits使用n个物理Qubt的n – 2逻辑量子，并带有一组通用的编码门。这样的方案不能完全容忍故障，但是可以弱化故障，能够通过最终（或中间）测量值检测到任何单个故障，并在选择后选择未检测到任何错误。对于小型计算，这将改善未编码的量子电路。随着配额计数的增加，噪声速率降低，可以添加更多FTQC元素，直到达到全断层耐受性为止。该项目还将解决准备Ancilla状态的问题，Ancilla状态是通过将基于状态的准备和验证结合到单个过程中的基于传送的FTQC的构建基础，该过程是使用基于标志的方法和错误检测的组合。研究人员还将针对QEC代码进行快速准确的解码算法，这些算法可以在量子计算过程中实时使用。该项目将通过机器学习方法开发解码算法。此外，该项目将探索QEC代码对量子信息科学中其他问题的应用。这项奖项反映了NSF的法定使命，并使用基金会的知识分子优点和更广泛的影响标准，被认为是值得的支持。