Non-equilibrium dynamics of quantum many-body systems

量子多体系统的非平衡动力学

• 批准号: 1308435
• 负责人: Eugene Demler
• 金额: $ 33万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-15 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1308435&HistoricalAwards=false
• 关键词: Non; equilibrium; dynamics; quantum; many

NONTECHNICAL SUMMARYThis award supports fundamental theoretical research and education to advance conceptual understanding of quantum mechanical systems of many particles that are far from the balanced state of equilibrium, such as electrons in materials or large molecules in a strong electric field. As electronic devices shrink to ever smaller sizes, quantum mechanics becomes increasingly important to describe their operation which becomes further from equilibrium than current device technologies. Motivation for this research comes from experiments on nanostructures, assemblies of atoms that are on a scale some 100,000 times smaller than the diameter of a human hair, nanomechanical systems such as biomolecular motors, systems of atoms that are trapped by light and cooled near the absolute zero of temperature, and as well as optical systems. This award supports theoretical research to develop concepts that are universally applicable across diverse quantum systems such as these by exploiting the ability to carry out carefully controlled experiments in one area, for example systems of ultracold atoms to advance understanding in another, such as transport of electrons in nanostructures, in which owing to contact with the environment, it is difficult to achieve the same level of control in experiments. The research will be integrated with education at several levels from graduate level course development to pedagogical lectures at international summer and winter schools. TECHNICAL SUMMARYThis award supports theoretical research and education to discover emergent universal behavior and to identify paradigms in the nonequilibrium dynamics of quantum many-body systems. The PI seeks to develop new concepts and new theoretical techniques motivated by experimental advances across condensed matter physics, ultracold atoms, and optics. The PI will use models, and theoretical and computational methods in close contact with experiments to study: relaxation and thermalization in nearly integrable systems, the conditions under which a hydrodynamic description is valid, the extent to which concepts from phase transitions and criticality apply, open and driven systems, and phenomena at the intersection of condensed matter and ultracold atom physics. The PI will develop new analytical and numerical methods aimed at understanding dynamical evolution of complex many-body systems. Analytical techniques will use exact Bethe ansatz solutions, perturbative expansions using nonequilibrium Keldysh formalism, the renormalization group approach, and analysis of effective field theories. Numerical approaches will include truncated Wigner approximation, time dependent dynamical mean-field renormalization group method, and dynamical mean-field theory calculations. The PI aims to exploit well controlled experiments on ultracold atoms together with theoretical advances to address the fundamental questions: Is there universality in nonequilibrium quantum dynamics at all? Is there emergent collective behavior which would enable the classification of quantum dynamics into several fundamental categories? The research will be integrated with education at several levels from graduate level course development to pedagogical lectures at international summer and winter schools.

该奖项支持基础理论研究和教育，以推进对许多远离平衡态的粒子的量子力学系统的概念理解，例如材料中的电子或强电场中的大分子。随着电子设备缩小到越来越小的尺寸，量子力学变得越来越重要，以描述它们的操作，这比当前的设备技术更远离平衡。这项研究的动机来自纳米结构的实验，原子的组装比人类头发直径小10万倍，纳米机械系统，如生物分子马达，被光捕获并在绝对零度附近冷却的原子系统，以及光学系统。该奖项支持理论研究，以开发普遍适用于各种量子系统的概念，例如通过利用在一个领域进行仔细控制实验的能力，例如超冷原子系统，以促进对另一个领域的理解，例如纳米结构中的电子传输，其中由于与环境接触，在实验中很难达到同样的控制水平。该研究将与从研究生课程开发到国际夏季和冬季学校的教学讲座等多个层次的教育相结合。该奖项支持理论研究和教育，以发现涌现的普遍行为，并确定量子多体系统非平衡动力学的范例。PI旨在开发新概念和新的理论技术，这些技术受到凝聚态物理，超冷原子和光学实验进展的推动。PI将使用模型，理论和计算方法与实验密切联系，以研究：近可积系统中的弛豫和热化，流体动力学描述有效的条件，相变和临界性概念的适用范围，开放和驱动系统，以及凝聚态和超冷原子物理学交叉点的现象。 PI将开发新的分析和数值方法，旨在了解复杂多体系统的动力学演化。分析技术将使用精确的Bethe anomalies解决方案，微扰扩展使用非平衡Keldysh形式主义，重整化群方法，和有效场理论的分析。数值方法将包括截断维格纳近似，时间相关的动态平均场重整化群方法，和动态平均场理论计算。PI的目标是利用超冷原子的良好控制实验以及理论进展来解决基本问题：非平衡量子动力学是否存在普适性？是否存在涌现的集体行为，使量子动力学能够分为几个基本类别？该研究将与从研究生课程开发到国际夏季和冬季学校的教学讲座等多个层次的教育相结合。