Dynamical Decoupling, Error Mitigation and Noise Correlations in Multi-Qubit Systems

多量子位系统中的动态解耦、误差缓解和噪声相关性

• 批准号: 1720311
• 负责人: Terry Orlando
• 金额: $ 36万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1720311&HistoricalAwards=false
• 关键词: Dynamical; Decoupling; Error; Mitigation; Noise

A quantum computer is a new type of device that could harness the power of quantum superposition, quantum entanglement, and quantum interference to dramatically reduce computation time for challenging problems. So far, quantum computational operations have only been realized in systems with a small number of quantum bits (qubits). The difficulty is that qubits are very sensitive to noise in their environment, which causes them to lose their quantum properties before there is enough time to perform any calculations. One way to improve the qubits is to develop new designs, using new materials and more refined fabrication techniques. A complimentary approach is to actively counteract the negative influence of the noise by applying a sequence of control pulses to the qubits, which decouples them from the noisy environment. This project will develop and implement such dynamical decoupling techniques for systems with coupled qubits, with the goal of further improving qubit performance and reducing error rates in multi-qubit systems.Any realistic quantum computer will need to implement error correction algorithms, so that residual errors can be handled as they occur. There exist several proposals for implementing quantum error correction, but common to protocols is that they put stringent requirements on the allowed error rate for performing single and multi-qubit gate operations. Even though contemporary qubit designs are close to threshold for certain protocols, it is important to realize that most quantum error correction protocols assume that the errors of individual qubits are uncorrelated, which is an oversimplification for most physical qubit systems. This project will focus on quantifying correlated noise in multi-qubit systems, which will be key for the development of more efficient quantum error correction protocols. In addition, this team will develop novel qubit control sequences for dynamically improving both qubit relaxation and dephasing times by reducing the number of quasiparticles close to the device.

量子计算机是一种新型设备，可以利用量子叠加、量子纠缠和量子干涉的力量来大幅缩短解决挑战性问题的计算时间。到目前为止，量子计算操作仅在具有少量量子比特（qubit）的系统中实现。困难在于，量子位对其环境中的噪声非常敏感，这导致它们在有足够的时间执行任何计算之前就失去了量子特性。改进量子位的一种方法是开发新设计，使用新材料和更精细的制造技术。 一种补充方法是通过向量子位施加一系列控制脉冲来主动抵消噪声的负面影响，从而将它们与噪声环境分离。该项目将为具有耦合量子位的系统开发和实现这种动态解耦技术，目标是进一步提高量子位性能并降低多量子位系统中的错误率。任何现实的量子计算机都需要实现纠错算法，以便在出现残余错误时可以对其进行处理。存在多种实现量子纠错的提议，但协议的共同点是它们对执行单量子位和多量子位门操作的允许错误率提出了严格的要求。尽管当代量子位设计接近某些协议的阈值，但重要的是要认识到大多数量子纠错协议假设各个量子位的错误是不相关的，这对于大多数物理量子位系统来说过于简单化。该项目将专注于量化多量子位系统中的相关噪声，这将是开发更高效的量子纠错协议的关键。此外，该团队将开发新颖的量子位控制序列，通过减少靠近设备的准粒子数量来动态改善量子位弛豫和移相时间。

项目成果

Two-Qubit Spectroscopy of Spatiotemporally Correlated Quantum Noise in Superconducting Qubits

• DOI: 10.1103/prxquantum.1.010305
• 发表时间: 2019-12
• 期刊: arXiv: Quantum Physics
• 作者: Uwe von Lupke;F. Beaudoin;Leigh M. Norris;Youngkyu Sung;R. Winik;J. Y. Qiu;M. Kjaergaard;David K. Kim;J. Yoder;S. Gustavsson;L. Viola;W. Oliver

Author Correction: Impact of ionizing radiation on superconducting qubit coherence

作者更正：电离辐射对超导量子位相干性的影响

• DOI: 10.1038/s41586-020-2754-2
• 发表时间: 2020
• 期刊: Nature
• 影响因子: 64.8
• 作者: Vepsäläinen, Antti P.;Karamlou, Amir H.;Orrell, John L.;Dogra, Akshunna S.;Loer, Ben;Vasconcelos, Francisca;Kim, David K.;Melville, Alexander J.;Niedzielski, Bethany M.;Yoder, Jonilyn L.
• 通讯作者: Yoder, Jonilyn L.

Tunable Coupling Scheme for Implementing High-Fidelity Two-Qubit Gates

• DOI: 10.1103/physrevapplied.10.054062
• 发表时间: 2018-03
• 期刊: Physical Review Applied
• 影响因子: 4.6
• 作者: F. Yan;P. Krantz;Youngkyu Sung;M. Kjaergaard;D. Campbell;J. Wang;T. Orlando;S. Gustavsson;W. Oliver