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New Superfluid States of 3He in Coherence Length Scale Nanofabricated Geometries

相干长度尺度纳米加工几何结构中 3He 的新超流体态

基本信息

批准号：
1202991
负责人：
Jeevak Parpia
金额：
$ 58万
依托单位：
Cornell University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2012
资助国家：
美国
起止时间：
2012-07-01 至 2018-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1202991&HistoricalAwards=false
关键词：
New Superfluid States 3He Coherence

项目摘要

****Technical abstract****The intellectual impact of the understanding of superfluid 3He extends across many fields in Physics. The program funded in this proposal will combine the field of nanofluidics with low temperature physics, to expose new size effects in a quantum fluid. By examination of the flow behavior of the quantum fluid the researchers seek to understand the influence of surface roughness on quantum transport. They will characterize the surface roughness necessary to allow the fluid to be locked to the surface or to slip at the surface. The surface roughness should also add quantifiable disorder to the quantum fluid. In planned experiments, the effect of confinement on the phase diagram will be examined with a view to exposing new (perhaps even handed or chiral) phases. The compressibility of 3He will allow the length scale of the coherence length to be pressure-tuned. By combining low temperatures and nano fabrication, two graduate students and several undergraduates will be exposed to the exciting training ground that has prepared scientists for lead roles in academia and high-technology industries. The proposed research will expose the stability of the superfluid order parameter to confinement, and look for new forms of superfluid under confinement on the way to a quantum phase transition where the superfluidity is extinguished. Such new superfluids might be of interest in quantum computation, and exposing in new types of vorticity. ****Non-Technical Abstract****Many of our everyday devices (think of cellphones, computers) originate from fundamental advances engendered by condensed matter research. In turn, future advances will rely on exploration of new regimes presently accessible only in a laboratory environment. The research to be conducted in this program will examine the special properties of superfluid 3He when confined in ultra small engineered cavities less than a thousandth of a millimeter tall, marking the transition from bulk 3 dimensional behavior to a new 2 dimensional regime. The flow of helium in these cavities should be dominated by the roughness of the surface and will slip if the surface is too smooth, or will be locked to the surface if the roughness is "just right". By examining flow, the researchers hope to better understand how quantum (as opposed to classical) fluids are different from each other. Quantum fluids display a "graininess" rather than a continuous behavior, and this quantum behavior is emphasized in reduced dimensions because the "grain" size increases. The reduced size will also be exploited in other ways to demonstrate new types of superfluid states that may show handedness like a spinning top. By combining low temperatures and nano fabrication, two graduate students and several undergraduates will be exposed to the exciting training ground that has prepared scientists for lead roles in academia and high-technology industries. The project will test what size range is relevant for the transformation from ordinary 3 Dimensional behavior to 2 Dimensional behavior.

****技术摘要****对超流体3He的理解的智力影响延伸到物理学的许多领域。该计划将结合纳米流体和低温物理领域，揭示量子流体中的新尺寸效应。通过研究量子流体的流动行为，研究人员试图了解表面粗糙度对量子输运的影响。它们将表征流体被锁定在表面或在表面滑动所必需的表面粗糙度。表面粗糙度也会给量子流体增加可量化的无序性。在计划的实验中，将检查约束对相图的影响，以期揭示新的相（甚至可能是手性或手性）。3He的可压缩性将允许对相干长度的长度尺度进行压力调节。通过低温和纳米制造的结合，两名研究生和几名本科生将接触到令人兴奋的训练场地，这些训练场地已经为科学家在学术界和高科技行业的领导角色做好了准备。所提出的研究将揭示约束下超流体序参量的稳定性，并在超流动性消失的量子相变过程中寻找约束下超流体的新形式。这种新的超流体可能对量子计算感兴趣，并暴露在新的涡量类型中。****非技术摘要****我们的许多日常设备（想想手机，电脑）都源于凝聚态物质研究带来的基本进步。反过来，未来的进展将依赖于目前只能在实验室环境中获得的新体制的探索。在这个项目中进行的研究将检查超流体3He在被限制在小于千分之一毫米高的超小工程腔中时的特殊性质，标志着从体三维行为到新的二维状态的过渡。氦气在这些空腔中的流动应该由表面的粗糙度决定，如果表面太光滑就会滑动，如果粗糙度“刚刚好”就会被锁在表面上。通过检测流体流动，研究人员希望更好地理解量子流体（与经典流体相反）彼此之间的不同之处。量子流体表现出“粒状”而不是连续的行为，这种量子行为在降维中被强调，因为“颗粒”大小增加了。缩小的尺寸也将在其他方面被利用来证明新型的超流体状态，这些超流体状态可能显示出像旋转的陀螺一样的手性。通过低温和纳米制造的结合，两名研究生和几名本科生将接触到令人兴奋的训练场地，这些训练场地已经为科学家在学术界和高科技行业的领导角色做好了准备。该项目将测试从普通三维行为到二维行为的转换相关的尺寸范围。