Dynamics, Thermodynamics and Spin Transport in Random Quantum Spin Chains

随机量子自旋链中的动力学、热力学和自旋输运

• 批准号: 9971541
• 负责人: Kun Yang
• 金额: $ 15万
• 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: 1999
• 资助国家: 美国
• 起止时间: 1999-06-01 至 2002-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9971541&HistoricalAwards=false
• 关键词: Dynamics; Thermodynamics; Spin; Transport; Random

9971541 Yang This award is comprised of a number of theoretical projects that are aimed at enhancing our understanding of the long-distance, low-energy properties of various random quantum magnetic systems, especially random spin chains. The motivation for these theoretical studies comes from both the extensive experimental activity with these types of systems, and the general interest in understanding the physics of quantum many-body systems with strong interaction/correlation and strong disorder.In general, strong interaction and disorder in many-body systems cannot be treated using standard perturbation theory, especially when the dimensionality of the system is low. Random quantum spin chains are typical examples of such systems. Powerful nonperturbative theoretical tools have been developed recently to study quantum spin chains, taking advantage of their one-dimensional nature. These tools include mapping onto effective quantum field theories, bosonization, real space renormalization group, etc.In the projects studied here, one uses and extends these tools to uncover important new information about the physical properties of these systems, including: the spin dynamics and transport properties of various stable phases supported by random spin chains; whether there exist new stable phases in random quantum spin chains that have not been studied before, when more general couplings (other than those studied thus far) among spins are allowed; the effects of transverse couplings between the chains on the physical properties; the effects of disorder generated by dynamical degrees of freedom in the system, etc. Attempts will also be made to develop new theoretical tools to study these systems, such as describing spin chains using field theories in terms of some novel non-local order parameters.Progress made on these projects is expected not only to deepen our understandings of the physics of various random quantum systems, but also to shed light on the properties of strongly interacting many-body systems in general. %%%This award is comprised of a number of theoretical projects that are aimed at enhancing our understanding of the long-distance, low-energy properties of various random quantum magnetic systems, especially random spin chains. The motivation for these theoretical studies comes from both the extensive experimental activity with these types of systems, and the general interest in understanding the physics of quantum many-body systems with strong interaction/correlation and strong disorder.Progress made on these projects is expected not only to deepen our understandings of the physics of various random quantum systems, but also to shed light on the properties of strongly interacting many-body systems in general.***

9971541杨该奖项由多个理论项目组成，旨在增进我们对长途运输的理解，各种随机量子磁系统的低能性质，特别是随机自旋链。这些理论研究的动机既来自于对这类系统的广泛实验活动，也源于人们对理解具有强相互作用/关联和强无序的量子多体系统物理的普遍兴趣。一般来说，标准微扰理论不能处理多体系统中的强相互作用和无序，特别是当系统的维度较低时。随机量子自旋链就是这类系统的典型例子。利用量子自旋链的一维性质，最近发展了强大的非微扰理论工具来研究量子自旋链。这些工具包括到有效量子场论的映射、玻色化、实空间重正化群等。在这里研究的项目中，人们使用和扩展这些工具来揭示关于这些系统物理性质的重要新信息，包括：由随机自旋链支撑的各种稳定相的自旋动力学和输运性质；随机量子自旋链中是否存在以前没有研究过的新的稳定相；当允许自旋之间更广泛的耦合(不包括迄今已研究的那些耦合)时；链之间的横向耦合对物理性质的影响；还将尝试发展新的理论工具来研究这些系统，例如用场论来描述自旋链，用一些新的非局域有序参数来描述自旋链。这些项目的进展不仅有望加深我们对各种随机量子系统物理的理解，而且还将揭示强相互作用多体系统的一般性质。该奖项由多个理论项目组成，旨在增进我们对各种随机量子磁系统，特别是随机自旋链的长距离、低能量性质的理解。这些理论研究的动机既来自于对这类系统的广泛实验活动，也来自于人们对理解具有强相互作用/关联和强无序的量子多体系统物理的普遍兴趣。这些项目的进展不仅有望加深我们对各种随机量子系统物理的理解，而且还将有助于揭示一般强相互作用多体系统的性质。