Interplay between symmetry breaking, quasiparticles and their topology in quantum condensed matter systems.

量子凝聚态物质系统中对称破缺、准粒子及其拓扑之间的相互作用。

• 批准号: 1506756
• 负责人: Oskar Vafek
• 金额: $ 29.92万
• 依托单位: Florida State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-15 至 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1506756&HistoricalAwards=false
• 关键词: Interplay; between; symmetry; breaking; quasiparticles

NONTECHNICAL SUMMARYThis award supports theoretical research and education on materials that can be tuned to display seemingly contradictory properties of matter, such as electrical insulation and superconductivity, an electronic state that can conduct electricity without dissipation. The goal of the research is to develop a better mathematical description of the underlying dynamical processes that cause such differentiation in the observed properties of the same physical system. The ultimate motivation is that understanding how the constituents of the system globally organize in different states will allow improved material design and control that take advantage of the proximity and interplay between these states.In a parallel project, the PI plans to study the mechanisms of Hall transport of heat in a class of superconductors with unusual properties compared to the simple, elemental superconductors. Hall transport of heat occurs in a material in the presence of magnetic field, and results in a temperature difference in the sample in a direction perpendicular to the magnetic field. Analysis and interpretation of experimental measurements of this type of heat transport in superconductors can help researchers distinguish between the various possible mechanisms that can cause superconductivity, and clarify the degree of competition between them. In addition, this project will enable training and mentoring of young scientists via participation in cutting-edge research.This award also supports the continuation of a Wiki textbook project which delivers freely available textbooks written by students based on faculty lecture notes. The PI plans to further build on this project expanding to new courses to become a vehicle for the dissemination of scientific knowledge.TECHNICAL SUMMARYThis award supports theoretical research and education aimed to develop a comprehensive theoretical description for a class of poorly understood phenomena in correlated quantum condensed matter systems, in which spontaneous symmetry breaking, quasiparticles, and their topology are inextricably linked. The projects involves analytical and numerical work on theoretical models that display on equal footing propensity towards spontaneous symmetry breaking into correlated non-superconducting states, as well as unconventional superconducting states that emerge in the vicinity of the latter. In addition, it explores Berry phases as a novel mechanism for thermal Hall transport of non-Landau quasiparticles, with the goal of developing a reliable tool for extracting valuable spectroscopic information from experimental data.Among the objectives are: determining the energy distribution of the Berry curvature of the quasiparticle wavefunctions in the mixed state of unconventional superconductors with different pairing symmetries; identifying the physical processes which control the recently discovered thermal activation scale of thermal Hall conductivity in what may otherwise be gapless systems; development of models of the vortex core which capture strong correlations; constructing a theory which would allow the study of the physical states both above and below the transition temperature in model systems with a multitude of interfering ordering tendencies; exploring the effects of charge-carrier doping of the quantum critical point associated with the transition between the Dirac semi-metal and the antiferromagnetic insulator on the honeycomb monolayer; further development of a theory of two- and three-dimensional quadratic band touching in physically motivated systems. The approach to all of these projects involves a combination of analytical and numerical methods of quantum many-body and/or field theory.This award also supports the continuation of a Wiki textbook project which delivers freely available textbooks written by students based on faculty lecture notes. The PI plans to further build on this project expanding to new courses to become a vehicle for the dissemination of scientific knowledge.

非技术摘要该奖项支持材料的理论研究和教育，这些材料可以通过调整来显示物质看似矛盾的特性，例如电绝缘性和超导性，一种可以导电而不耗散的电子状态。该研究的目标是对导致同一物理系统的观察到的特性出现这种差异的潜在动态过程进行更好的数学描述。最终的动机是，了解系统的组成部分如何在不同的状态下进行全球组织，将能够改进材料设计和控制，从而利用这些状态之间的邻近性和相互作用。在一个并行项目中，PI 计划研究霍尔的机制与简单的元素超导体相比，一类具有不寻常特性的超导体中的热传输。在存在磁场的情况下，材料中会发生霍尔热传输，并导致样品在垂直于磁场的方向上产生温差。对超导体中此类热传输的实验测量进行分析和解释可以帮助研究人员区分引起超导性的各种可能机制，并阐明它们之间的竞争程度。此外，该项目还将通过参与前沿研究来培训和指导年轻科学家。该奖项还支持维基教科书项目的继续，该项目免费提供由学生根据教师讲义编写的教科书。 PI 计划进一步在该项目的基础上扩展到新课程，成为传播科学知识的工具。技术摘要该奖项支持理论研究和教育，旨在为相关量子凝聚态中一类鲜为人知的现象开发全面的理论描述。物质系统，其中自发对称破缺、准粒子及其拓扑结构有着千丝万缕的联系。这些项目涉及理论模型的分析和数值工作，这些模型显示出自发对称性突破相关非超导态以及后者附近出现的非常规超导态的同等倾向。此外，它还探索了贝里相作为非朗道准粒子热霍尔传输的一种新机制，目标是开发一种可靠的工具，从实验数据中提取有价值的光谱信息。目标包括：确定贝里相的能量分布具有不同配对对称性的非常规超导体混合状态下准粒子波函数的曲率；识别控制最近发现的热霍尔传导率的热激活规模的物理过程，否则可能是无间隙系统；开发捕捉强相关性的涡核模型；构建一种理论，允许研究具有多种干扰排序倾向的模型系统中高于和低于转变温度的物理状态；探索与狄拉克半金属和反铁磁绝缘体之间的转变相关的量子临界点的载流子掺杂对蜂窝单层的影响；物理激励系统中二维和三维二次带接触理论的进一步发展。所有这些项目的方法都涉及量子多体和/或场论的分析和数值方法的结合。该奖项还支持维基教科书项目的继续，该项目免费提供由学生根据教师讲义编写的教科书。 PI 计划进一步在该项目的基础上扩展到新课程，成为传播科学知识的工具。