RUI: Theoretical Study of Quantum Control and Coherence Preserving Strategies in Solid State Spin Qubits

该奖项支持理论研究和本科生教育，重点是量子比特的设计和建模，量子比特通过半导体量子点中的自旋实现。该研究将阐明基于自旋的量子信息处理器的几个关键方面，重点是控制量子点中自旋的相干特性并使其能够控制和操纵的物理机制。利用各种分析和数值技术，PI和他的研究学生将研究波动的电荷和核环境，其在交换耦合III-V量子点中的电子自旋退相干中起关键作用。 电子自旋量子比特的相干特性将在各种操纵协议下进行分析，在正在进行的实验和拟议的量子比特设计的背景下。新的配方，延长电子自旋退相的现行理论的有效性将进行探讨。此外，混合量子位设计，提供更好的退相干免疫力，如三自旋量子位将被研究沿着多量子位器件的耦合策略。超越目前采用的去耦脉冲序列，PI将探索与时间相关的控制场，可以扩展量子力学自旋态的演化。最后，该奖项支持的工作将开发和模拟利用超精细相互作用产生纠缠核态的光学和电学控制方法，为核集体态提供新的控制水平。该奖项支持的项目将在圣克拉拉大学进行，这是一所私立本科院校，并将在整个期间通过独立的研究项目为本科生提供教育机会。学生将积极参与前沿物理研究，这将培养他们先进的理论方法和高端数值分析。该研究将采用各种方法和工作模式，从多体问题和半导体异质结构中的自旋物理到并行计算计算机集群环境的代码编写。这种多样性确保了学生可以追求多个独立的调查路线，以便在全日制夏季期间完成独立的研究项目。参与的学生将接触到量子计算的高度活跃和跨学科研究领域的领先实验和理论研究。近年来，量子信息处理的广泛兴趣已经成为半导体量子点中局域化电子自旋研究的关键驱动力。自旋与电子相关;自旋是一种内在的量子力学性质，可以用来在半导体表面或量子点的工程丘中制造双态量子力学系统或量子位。该奖项支持理论研究和本科教育计划，旨在阐明基于自旋的量子信息处理器的几个关键方面，专注于控制量子点中自旋相干特性的物理机制，并使其能够控制和操纵。成功设计量子比特的两个主要因素-量子计算机的构建模块-正在保持其脆弱状态的一致性，并找到允许在单量子位和双量子位水平上进行高保真量子位控制和操纵的机制。解决第一个问题，PI和他的研究生将建模和分析波动的电荷和核环境，这形成了电子自旋量子比特的主要退相干通道。 更好地了解当前实验设置中环境对自旋量子位的不利影响，将使团队能够测试和提出扩展相干性的策略，包括时间相关的控制场，新颖的量子位设计以及三个电子自旋物理状态中逻辑状态的编码。该奖项支持的研究将进一步探索多量子位器件的耦合策略，并开发光学和电学方法，通过利用它们与局域电子自旋的超精细相互作用来控制量子点衬底中的核自旋。 通过该奖项支持的计划将在圣克拉拉大学进行，这是一所私立本科院校，并将在整个期间通过独立的研究项目为本科生提供教育机会。学生将参加尖端的物理研究，这将培养他们在先进的理论方法和高端数值分析。各种理论方法和工作模式将确保学生将追求多个和独立的调查线，使独立的研究项目可以在全职夏季期间完成。参与的学生将接触到量子计算的高度活跃和跨学科研究领域的领先实验和理论研究。

TECHNICAL SUMMARYThis award supports theoretical research and undergraduate education focused on the design and modeling of quantum bits, qubits, realized by spins localized in semiconductor quantum dots. The study will elucidate several of the key aspects of spin-based quantum information processors, focusing on the physical mechanisms that govern the coherence properties of spins in quantum dots and enable their control and manipulation.Utilizing a variety of analytical and numerical techniques, the PI and his research students will study the fluctuating charge and nuclear environments, which play a crucial role in electron spin decoherence in exchange-coupled III-V quantum dots. Coherence properties of electron-spin qubits will be analyzed under various manipulation protocols, in the context of ongoing experiments and proposed qubit designs. New formulations that extend the validity of current theories of electron-spin dephasing will be explored. In addition, hybrid qubit designs that offer better decoherence immunity, such as three-spin qubits will be investigated along with coupling strategies for multi-qubit devices. Going beyond the currently employed decoupling pulse sequences, the PI will explore time-dependent control fields that can extend the evolution of the quantum mechanical spin states. Finally the work supported with this award will develop and model optical and electrical control methods that utilize the hyperfine interaction to generate entangled nuclear states, offering new level of control over the nuclear collective states.The program supported through this award will be carried out at Santa Clara University, a Primarily Undergraduate Institution, and will provide educational opportunities for undergraduate students through independent research projects throughout its duration. Students will take active part in cutting-edge physics research that will train them in advanced theoretical methods and high-end numerical analysis. The research will employ a variety of methods and work modalities, ranging from many-body problems and spin physics in semiconductor heterostructures to code writing for parallel computing computer cluster environment. This diversity ensures that students can pursue multiple and independent lines of investigation so that self-contained research projects will be completed within a full-time summer period. Participating students will be exposed to the leading experimental and theoretical endeavors in the highly vibrant and interdisciplinary research field of quantum computing. NON-TECHNICAL SUMMARYThe wide-spread interest in quantum information processing in recent years has been a critical driving force in the research of electron spins localized in semiconductor quantum dots. The spins are associated with electrons; spin is an intrinsic quantum mechanical property that can be exploited to make a two-state quantum mechanical system, or qubit, in the engineered mound of a semiconductor surface or quantum dot. This award supports a theoretical research and undergraduate education program aimed at elucidating several of the key aspects of spin-based quantum information processors, focusing on the physical mechanisms that govern the coherence properties of spins in quantum dots and enable their control and manipulation.The two main ingredients of a successful design of qubits - the building blocks of a quantum computer - are preserving the coherence of their fragile states and finding mechanisms that will allow high fidelity qubit control and manipulation at the single- and two-qubit level. Addressing the first, the PI and his research students will model and analyze the fluctuating charge and nuclear environments, which form the main decoherence channels for electron spin qubits. A better understanding of the adverse effects of the environment on spin qubits at current experimental setups will allow the team to test and propose strategies to extend coherence, including time-dependent control fields, novel qubit designs, and encoding of the logical states in physical states of three electron spins. The research supported by this award will further explore coupling strategies for multi-qubit devices and develop optical and electrical methods to control the nuclear spins in the quantum dot substrate, by utilizing their hyperfine interaction with the localized electron spins. The program supported through this award will be carried out at Santa Clara University, a Primarily Undergraduate Institution, and will provide educational opportunities for undergraduate students through independent research projects throughout its duration. Students will participate in cutting-edge physics research that will train them in advanced theoretical methods and high-end numerical analysis. A variety of theoretical methods and work modalities will ensure that students will pursue multiple and independent lines of investigation so that self-contained research projects can be completed within a full-time summer period. Participating students will be exposed to the leading experimental and theoretical endeavors in the highly vibrant and interdisciplinary research field of quantum computing.