Simulation Studies of Ground State Phases and Criticality in Correlated Quantum Matter

相关量子物质的基态相和临界性的模拟研究

• 批准号: 0513930
• 负责人: Anders Sandvik
• 金额: $ 24.6万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0513930&HistoricalAwards=false
• 关键词: Simulation; Studies; Ground; State; Phases

TECHNICAL EXPLANATION:This award supports computational and theoretical research that aims to elucidate the nature of complex ground states and quantum phase transitions in strongly correlated electron systems. Research involves large-scale simulation studies of quantum spin models. These will use advanced quantum Monte Carlo methods, primarily those based on the stochastic series expansion (SSE) formulation of quantum statistical mechanics developed by the PI. The PI will continue to develop simulation algorithms. The specific models to be studied include a two-dimensional hard-core boson model with a ring-exchange term. An aim of this work is to accurately characterize the superfluid to valence-bond-solid transition, which has been proposed to be a "deconfined" quantum-critical point. A Heisenberg model will be studied with the aim of achieving an O(3)-symmetric antiferromagnetic to spin-liquid transition. Heisenberg models with strong disorder in the form of dilution will be investigated with the aim of characterizing the quantum phase transitions that are possible within this framework. New SSE algorithms that will result from this work may impact research in other fields, for example lattice gauge theory and quantum information theory. Beyond training students in physics and advanced scientific computing, this award supports the construction of a web-site in which the SSE method is presented in a pedagogical manner and along with example programs for a various models.NON-TECHNICAL EXPLANATION:This award supports computational and theoretical research that engages issues at the heart of modern theoretical condensed matter physics that are inspired by the discovery of materials in which the electrons organize themselves to form unusual states of matter. High temperature superconductors and related compounds are among these materials. The PI will use advanced computational methods and streamlined models designed to strip away unnecessary detail and focus on the essential physics needed to understand these complex materials. The use of computational techniques aimed at ascertaining the exact solution to these models complements analytical theory efforts and provides insight that is not accessible to traditional experiments. The PI will further investigate a transformation among electronic phases that occurs at the absolute zero of temperature, and lies outside the standard theory of phase transitions. This new kind of phase transition advances our understanding of phase transitions and may be a key piece in the challenging puzzle of understanding high temperature superconductors and other strongly correlated materials. The understanding of this and other quantum phase transitions may have impact across physics and other fields. The proposal also supports an outreach activity to make the PI's computational methods more broadly accessible to the research community.

该奖项支持旨在阐明强关联电子系统中复杂基态和量子相变性质的计算和理论研究。研究涉及量子自旋模型的大规模模拟研究。这些将使用先进的量子蒙特卡罗方法，主要是那些基于PI开发的量子统计力学的随机级数展开（SSE）公式的方法。PI将继续开发模拟算法。具体的模型进行研究，包括一个二维的硬核玻色子模型与环交换项。这项工作的一个目的是准确地描述超流体的价键固体转变，这已被提出是一个“解除限制”的量子临界点。海森堡模型将被研究，目的是实现O（3）对称的反铁磁自旋液体的转变。海森堡模型与稀释形式的强无序将被调查的目的是表征量子相变，在这个框架内是可能的。这项工作产生的新SSE算法可能会影响其他领域的研究，例如格点规范理论和量子信息理论。除了培养学生在物理学和先进的科学计算，该奖项还支持建立一个网站，其中以教学的方式介绍SSE方法，并沿着各种模型的示例程序。非技术性解释：该奖项支持计算和理论研究，这些研究涉及现代理论凝聚态物理学的核心问题，这些问题的灵感来自于发现电子在其中组织自己形成不寻常的物质状态的材料。高温超导体和相关的化合物是这些材料中的一种。PI将使用先进的计算方法和流线型模型，旨在去除不必要的细节，并专注于理解这些复杂材料所需的基本物理学。旨在确定这些模型的精确解的计算技术的使用补充了分析理论的努力，并提供了传统实验无法获得的洞察力。PI将进一步研究在绝对零度温度下发生的电子相位之间的转换，并且位于相变的标准理论之外。这种新的相变推进了我们对相变的理解，可能是理解高温超导体和其他强相关材料的挑战性难题的关键部分。对这种和其他量子相变的理解可能会影响物理学和其他领域。该提案还支持一项外展活动，使PI的计算方法更广泛地为研究界所用。