CAREER: New Regimes of Coherent Nonequilibrium Dynamics in Quantum Many-Body Systems

该职业奖支持非平衡量子动力学广泛领域的理论研究和教育，并着眼于新兴量子技术。量子计算是利用量子力学原理来存储和处理信息的一种新的计算模式。快速的实验进展正在引领一个有用的短期量子计算平台时代，其潜在应用范围从密码学到药物设计。量子计算依赖于控制许多相互作用的量子粒子系统的非平衡动力学。因此，了解这种动态对促进未来的进步起着至关重要的作用。多粒子量子系统往往会丢失有关其制备状态的信息。这种被称为量子遍历性的趋势对量子计算是有害的，量子计算取决于保持微妙量子态并对其进行操作的能力。该项目的研究部分将发展对各种机制的理论理解，通过这些机制可以避免量子遍历性。它还将考虑如何在当今的量子硬件上实现这些机制，其长期目标是扩展用于研究和操纵复杂量子系统的工具包。量子科学与技术已被确定为国家重点研究领域。在这一领域保持领导地位需要培养一支强大的量子劳动力队伍。为此，该项目的教育部分包括在爱荷华州立大学（ISU）开发跨学科量子计算课程，其成功将增加量子人才管道。首席研究员还将与isu领导的两项计划（Science Bound和Go Further）合作，围绕量子物理主题开展外展活动，旨在增加科学、技术、工程和数学领域代表性不足的群体的参与。这些活动将涉及数百名大学预科生和大学生，并利用实践活动和主动学习方法激发人们对量子物理学的热情。该奖项支持非平衡量子动力学广泛领域的理论研究和教育，并着眼于新兴量子技术。研究部分解决了量子多体系统在强相互作用下如何不能松弛到热平衡并保持量子相干性的基本问题。研究活动分为三个相互关联的重点，其目标是：(1)阐明紧急动态约束在规范理论和相关量子自旋模型的非平衡行为中的作用。我们将结合微扰理论和数值精确对角化来研究这一问题，以提取这类系统中松弛过程的时间尺度。(2)探索量子多体伤痕的一般构造，这是一种可以通过在特殊类型的初始状态下制备系统来避免热化的动力状态。这种结构取决于无限温度热场双态的使用，这在高能物理学和量子信息科学界都很感兴趣。(3)发现量子电路固有的热化和退相干的新障碍，量子电路是量子计算的自然环境。本项目主要研究与经典元胞自动机相关的量子电路，以及基于确定性非周期序列的量子电路。这三个主题都与当今的实验平台有关，包括玻色子和费米子的冷原子气体，光学镊子中的里德伯原子阵列，以及当今嘈杂的中等规模量子硬件。该项目的教育部分包括在爱荷华州立大学（ISU）开发跨学科量子计算课程，其成功将增加量子人才管道。PI还将与国际数学联盟领导的两项倡议合作，围绕量子物理主题开展外联活动，即“科学束缚”和“走得更远”，旨在增加未被充分代表的群体在科学、技术、工程和数学领域的参与。这些活动将涉及数百名大学预科生和大学生，并利用实践活动和主动学习方法激发人们对量子物理学的热情。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

NONTECHNICAL SUMMARYThis CAREER award supports theoretical research and education in the broad field of nonequilibrium quantum dynamics with a view towards emerging quantum technologies. Quantum computing is a new mode of computation that harnesses the principles of quantum mechanics to store and process information. Rapid experimental progress is ushering in an era of useful near-term quantum computing platforms, with potential applications ranging from cryptography to drug design. Quantum computation relies on controlling the nonequilibrium dynamics of systems of many interacting quantum particles. Comprehending such dynamics thus plays a critical role in enabling future advances. Many-particle quantum systems tend to lose information about the state in which they were prepared. This tendency, known as quantum ergodicity, is detrimental to quantum computation, which hinges on the ability to preserve delicate quantum states and perform operations on them. The research component of this project will develop a theoretical understanding of a variety of mechanisms through which quantum ergodicity can be avoided. It will also consider how to realize these mechanisms on present-day quantum hardware with the long-term goal of expanding the toolkit for the study and manipulation of complex quantum systems.Quantum science and technology has been identified as a key national research priority. Sustaining leadership in this field requires nurturing a robust quantum workforce. To this end, the education component of this project includes developing an interdisciplinary quantum computing curriculum at Iowa State University (ISU), whose success will grow the quantum talent pipeline. The principal investigator will also engage in outreach around quantum physics topics in partnership with two ISU-led initiatives, Science Bound and Go Further, aimed at increasing the participation of underrepresented groups in science, technology, engineering, and mathematics. These activities will reach hundreds of precollege and college students and tap into popular excitement about quantum physics using hands-on activities and active learning approaches.TECHNICAL SUMMARYThis CAREER award supports theoretical research and education in the broad field of nonequilibrium quantum dynamics with a view towards emerging quantum technologies. The research component addresses the foundational question of how quantum many-body systems can fail to relax to thermal equilibrium and maintain quantum coherence in the presence of strong interactions. Research activities are organized into three interrelated thrusts whose goals are: (1) Elucidate the role of emergent dynamical constraints in the far-from-equilibrium behavior of gauge theories and related quantum spin models. This question will be investigated using a combination of perturbation theory and numerical exact diagonalization to extract the timescales of relaxation processes in such systems. (2) Explore a general construction of quantum many-body scars, a dynamical regime where thermalization can be avoided by preparing the system in a special class of initial states. The construction hinges on the use of infinite-temperature thermofield-double states, which are of interest in both the high-energy physics and quantum information science communities. (3) Discover novel roadblocks to thermalization and decoherence intrinsic to quantum circuits, the natural setting for quantum computation. This project focuses on quantum circuits related to classical cellular automata, as well as circuits based on deterministic aperioidic sequences. All three topics are relevant to present-day experiments on platforms including cold atomic gases of bosons and fermions, arrays of Rydberg atoms in optical tweezers, and present day noisy intermediate-scale quantum hardware.The education component of this project includes developing an interdisciplinary quantum computing curriculum at Iowa State University (ISU), whose success will grow the quantum talent pipeline. The PI will also engage in outreach around quantum physics topics in partnership with two ISU-led initiatives, Science Bound and Go Further, aimed at increasing the participation of underrepresented groups in science, technology, engineering, and mathematics. These activities will reach hundreds of precollege and college students and tap into popular excitement about quantum physics using hands-on activities and active learning approaches.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.