RAISE-TAQS: Symmetry Protected Quantum Bits through Fluxon Pairing

RAISE-TAQS：通过 Fluxon 配对保护对称性的量子比特

• 批准号: 1838979
• 负责人: Matthew Bell
• 金额: $ 99.18万
• 依托单位: University of Massachusetts Boston
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-15 至 2024-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1838979&HistoricalAwards=false
• 关键词: RAISE; TAQS; Symmetry; Protected; Quantum

Non-technical description: With the current pace of quantum technology development, the realization of a superconducting quantum computer is fast approaching. Quantum computers offer the possibility for exponential speedup in computation in comparison to classical computers on some of the hardest problems relevant to humanity today. Over the past decade, the performance of the elements of a quantum computer, the quantum bit (qubit) has improved tremendously. Despite this progress in performance, it has been shown that there is still a long way to go in improving qubit performance to realize a practical quantum computer. The goal of this project is to design, fabricate, and characterize a new class of fault-tolerant logical qubits for a quantum computer decoupled from the environment and protected from local noises. The logical qubit is based on incorporating error correction at the hardware level utilizing nontrivial symmetries and engineering quantum mechanical interactions in the circuit which makes up the qubit. This research project contributes to a better understanding of how certain quantum interactions which have typically not been exploited in quantum computers can be utilized to improve qubit performance and scalability. The educational outreach portion of this project addresses the need to train future quantum electronics engineers for positions which are currently in high demand in the quantum technologies industry encompassing both tech industry giants and a quantum startup ecosystem. Such activities encompass the introduction of a series of short courses on introductory quantum information sciences targeted at physics and electrical engineering students early on in their careers, exposing them to opportunities in the ever-expanding quantum technology industry.Technical description: The project investigates transformative ideas of realizing highly coherent qubits through symmetry-protection of a quantum state encoded in the parity of fluxons in a superconducting loop. The proposed qubit provides a Hamiltonian realization of an error correction code where the ground states of the Hamiltonian can be regarded as the logical basis states. The realization of a full-fledged topologically protected quantum state in a circuit has been elusive primarily because alternative approaches have required elements not found in the conventional superconducting circuit toolbox. This project utilizes two newly developed circuit elements, the charge-based quantum interference device and a superinductor, to realize a protected fluxon-pairing quantum circuit, a cos(phi/2) Josephson element whose lowest-energy states are different by the parity of fluxons in a superconducting loop. It is expected that such a circuit could be decoupled from local noises and demonstrate very long coherence in the protected state. The objectives of this project are: (1) to develop a highly coherent fluxon-pairing qubit by first enhancing the Aharonov-Casher interference through symmetry improvements in the design of the qubit; (2) to further develop superinductor technology; (3) to demonstrate protection against energy relaxation and de-coherence in the protected state of the fluxon-pairing qubit; (4) to demonstrate fast adiabatic switching between the protected and unprotected states for state preparation and measurement operations; and (5) to demonstrate fault-tolerant single and two-qubit gate operations on the sub-microsecond time scale. The project also supports the education of graduate students who enjoy broad exposure to the state-of-the-art tools of modern quantum information research. The multi-component educational and outreach component, an essential part of the project, is designed to develop a program to train future quantum electronics engineers.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.

非技术描述：随着量子技术开发的当前速度，超导量子计算机的实现快速接近。与当今与人类有关的一些最困难的问题相比，量子计算机提供了计算中指数加速的可能性。在过去的十年中，量子计算机的元素的性能，量子位（Qubit）大大提高。尽管性能取得了这种进步，但已经表明，改善量子性能以实现实用的量子计算机还有很长的路要走。该项目的目的是设计，制造和表征一类新的容忍故障的逻辑量子，以使量子计算机与环境解耦并免受本地噪声的保护。逻辑量子位基于在硬件级别上使用误差校正，利用构成量子位的电路中的非平凡对称性和工程量子机械相互作用。该研究项目有助于更好地了解某些通常在量子计算机中未被利用的量子相互作用如何用于提高量子性能和可扩展性。该项目的教育外展部分旨在培训未来的量子电子工程师的职位，这些职位目前涵盖技术行业巨头和量子启动生态系统的量子技术行业需求很高。此类活动涵盖了一系列针对物理和电气工程专业学生的入门量子信息科学的简短课程，使他们在其职业生涯的早期介绍了他们的机会，在不断扩展的量子技术行业中，技术描述：该项目调查了通过对量子范围的Symmetry Protection in QuarbiT of量子范围来研究的高度相干质量的变革性思想，该量子是量子范围的A a flflux a a a a flflux a a a a a a a a a flflux a a a a a a a a a a a a a a量的范围。拟议的量子量Qubit提供了对误差校正法规的实现，其中哈密顿量的基态可以被视为逻辑基础状态。在电路中实现全面拓扑保护的量子状态的实现非常难以捉摸，这主要是因为替代方法需要在常规的超导电路工具箱中找到的元素。该项目利用了两个新开发的电路元件，即基于电荷的量子干扰装置和一个超级电阻器，以实现受保护的Fluxon Pairing量子电路，即COS（PHI/2）Josephson元素，其最低能量状态的最低能状态与超导循环中的磁通量的均等相差。可以预期，这种电路可以与局部噪声解耦，并在受保护状态下表现出很长的连贯性。该项目的目标是：（1）通过首先通过对称量子设计的对称性改进来增强Aharonov-Casher干扰，以开发高度连贯的Fluxon配对量子。 （2）进一步开发超级电感技术； （3）证明在Fluxon配对量子的受保护状态下的能量松弛和去糖化； （4）证明在受保护和未保护状态之间进行状态准备和测量操作之间的快速绝热切换； （5）在子微秒时尺度上演示易耐断层的单一和两数Quibent的门操作。该项目还支持接受广泛接触现代量子信息研究最先进工具的研究生的教育。该项目的重要组成部分旨在制定一项计划来培训未来的量子电子工程师。该奖项反映了NSF的法定任务，并认为使用基金会的知识分子和更广泛的影响标准通过评估，审查标准。

项目成果

Bifluxon: Fluxon-Parity-Protected Superconducting Qubit

• DOI: 10.1103/prxquantum.1.010307
• 发表时间: 2020-09-03
• 期刊: PRX QUANTUM
• 影响因子: 9.7
• 作者: Kalashnikov, Konstantin;Hsieh, Wen Ting;Bell, Matthew
• 通讯作者: Bell, Matthew

Phase Diffusion in Low-EJ Josephson Junctions at Milli-Kelvin Temperatures

• DOI: 10.3390/electronics12020416
• 发表时间: 2023-01-01
• 期刊: ELECTRONICS
• 影响因子: 2.9
• 作者: Lu, Wen-Sen;Kalashnikov, Konstantin;Gershenson, Michael E.
• 通讯作者: Gershenson, Michael E.

Granular Aluminum Meandered Superinductors for Quantum Circuits

• DOI: 10.1103/physrevapplied.13.054051
• 发表时间: 2020-05-20
• 期刊: PHYSICAL REVIEW APPLIED
• 影响因子: 4.6
• 作者: Kamenov, Plamen;Lu, Wen-Sen;Gershenson, Michael E.
• 通讯作者: Gershenson, Michael E.