Magneto-Acoustic and Quantum Transport in Helium Three

氦三中的磁声和量子输运

• 批准号: 0805277
• 负责人: James Sauls
• 金额: $ 27.6万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-11-15 至 2012-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0805277&HistoricalAwards=false
• 关键词: Magneto; Acoustic; Quantum; Transport; Helium

TECHNICAL SUMMARY:This award supports research and education in theoretical condensed matter physics in magneto-acoustic and quantum transport in helium three. The theoretical investigations describe and explain newly discovered and newly predicted quantum condensed phases of matter. The research responds to recent experimental results establishing the existence of new superfluid phases of 3He in confined geometries and the existence of new collective modes of superfluid 3He exhibiting unusual magneto-acoustic properties, including acoustic birefringence of transverse sound. Transverse magneto-optical phenomena have been recently observed in electronic superconductors. The theoretical efforts address predicting and characterizing the magneto-optical and magneto-acoustic properties of quantum condensed phases of 3He. Another vein of research develops theory to predict new phases of 3He with properties characteristic of both solid and superfluid states of matter, i.e. ''crystalline order in superfluid 3He''. In particular, the PI will carry out theoretical research based on transport theory for quantum fluids that will examine the physical properties and experimental signatures of this predicted phase of 3He. A third effort employs theoretical models and quantum statistical methods for analyzing the interplay between ordering associated with symmetry breaking phase transitions, and extrinsic disorder that is present in virtually all macroscopic forms of matter. These theoretical developments connect with the experimental systems of liquid 3He impregnated into low-density silica glass, also called aerogel. This system permits theory to compare to a controllable and tunable medium to study effects of quenched random disorder in strongly correlated Fermi liquids.The research has a strong education component involving the training of graduate students and a continuation of the PI's long history of recruiting undergraduates in cutting edge research projects with publishable outcomes. The research connects with substantial international collaborations in Germany and France focused on the research topic, thereby strengthening and enriching the US physical community.NON-TECHNICAL SUMMARY:This award supports research and education in theoretical studies of a unique fluid, helium three, which exhibits magnetic and flow properties governed by the laws of quantum physics. Just as common materials exhibit different phases such as the liquid, gas and solid phases, so do quantum fluids, but the laws of quantum physics allow a wealth of complexities not normally encountered in everyday materials. The theoretical investigations of this research describe and explain newly discovered and newly predicted quantum phases of the fluid. The research responds to recent experimental results establishing the existence of new quantum phases of helium three which occur if the fluid is confined in small regions of space, such as cavities, droplets or films. In these confined geometries the existence of new physical behavior is exhibited as remarkable magnetic properties that appear when sound travels through the droplet or the film of liquid. Such behaviors reflect the quantum laws of nature operating in the liquid. These phenomena allow for a deeper understanding of similar phenomena in the technologically important superconductors, which can carry electricity with no energy loss. The theoretical efforts extend to other geometries that are important for investigating a wide range of quantum behavior, and in expanding basic scientific understanding beyond helium three to superconducting wires, and to practical quantum electronic and magnetic devices that will be part of the next revolution in ultra-miniaturization and quantum computers.The research has a strong education component involving the training of graduate students and a continuation of the PI's long history of recruiting undergraduates in cutting edge research projects with publishable outcomes. The research connects with substantial international collaborations in Germany and France focused on the research topic, thereby strengthening and enriching the US physical community.

技术综述：该奖项支持理论凝聚态物理在磁声和氦3中的量子输运方面的研究和教育。理论研究描述和解释了新发现的和新预测的物质的量子凝聚相。这项研究响应了最近的实验结果，这些结果证实了在受限几何结构中存在新的3He超流相，以及存在表现出异常磁声性质的新的超流3He集体模，包括横声波的声双折射。最近在电子超导体中观察到了横向磁光现象。理论工作致力于预测和表征3He的量子凝聚相的磁光和磁声性质。另一种研究方向是用物质的固体和超流状态的性质来预测3He的新相，即“超流3He中的结晶顺序”。特别是，PI将根据量子流体的输运理论进行理论研究，检查3He预测相的物理性质和实验特征。第三项工作使用理论模型和量子统计方法来分析与对称破缺相变相关的有序性和几乎存在于所有宏观物质形式中的外在无序之间的相互作用。这些理论发展与液体3He浸入低密度二氧化硅玻璃(也称为气凝胶)的实验系统有关。这一系统允许将理论与一种可控和可调的介质进行比较，以研究强关联费米液体中猝灭的随机无序的影响。这项研究具有强大的教育成分，涉及研究生的培训，并延续了PI在尖端研究项目中招募本科生的长期历史，这些研究项目具有可发表的结果。这项研究与德国和法国专注于这一研究主题的大量国际合作相联系，从而加强和丰富了美国物理界。非技术概述：该奖项支持对一种独特的流体--氦三的理论研究和教育，这种流体表现出受量子物理定律支配的磁性和流动特性。就像常见的材料表现出不同的相，如液体、气相和固相一样，量子流体也是如此，但量子物理定律允许出现日常材料中通常不会遇到的丰富的复杂性。这项研究的理论研究描述和解释了新发现的和新预测的流体的量子相。这项研究回应了最近的实验结果，该实验结果证实了氦三的新量子相的存在，如果流体被限制在空间的小区域，如腔、液滴或薄膜，就会出现这种新的量子相。在这些受限的几何形状中，新的物理行为的存在表现为当声音通过液滴或液膜传播时出现的显着的磁性。这些行为反映了自然界在液体中运行的量子定律。这些现象使人们能够更深入地了解具有重要技术意义的超导体中的类似现象，这种超导体可以在没有能量损失的情况下携带电能。这些理论工作延伸到其他几何学，这些几何学对于研究广泛的量子行为、将基本的科学理解从氦3扩展到超导导线，以及将成为下一次超小型化和量子计算机革命的实用量子电子和磁器件都是重要的。这项研究有一个强大的教育组成部分，涉及研究生的培训，并延续了PI在尖端研究项目中招收本科生的悠久历史，这些研究项目的成果是可以发表的。这项研究与德国和法国围绕这一研究主题的大量国际合作联系在一起，从而加强和丰富了美国物理界。