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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的理解所产生的智力影响延伸到物理学的许多领域。这项计划将联合收割机与低温物理学相结合，揭示量子流体中新的尺寸效应。通过检查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。它们将表征允许流体被锁定到表面或在表面滑动所需的表面粗糙度。表面粗糙度还应该为量子流体增加可量化的无序。在计划的实验中，将检查限制对相图的影响，以揭示新的（甚至可能是手或手征）相。3He的可压缩性将允许相干长度的长度尺度被压力调谐。通过结合低温和纳米制造，两名研究生和几名本科生将接触到令人兴奋的训练场，为科学家在学术界和高科技行业的领导角色做好准备。拟议的研究将揭示超流序参量对限制的稳定性，并在限制下寻找新形式的超流，以实现超流熄灭的量子相变。这种新的超流体可能会在量子计算中引起兴趣，并暴露在新类型的涡旋中。* 非技术摘要 * 我们的许多日常设备（想想手机，电脑）都源于凝聚态研究的基本进展。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机制的探索。在该计划中进行的研究将检查超流3He的特殊性质，当被限制在小于千分之一毫米高的超小工程腔中时，标志着从大体积三维行为到新的二维状态的过渡。氦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，则会滑动，或者如果粗糙度“刚刚好”，则会锁定在表面上。通过研究流动，研究人员希望更好地了解量子（与经典相反）流体彼此之间的差异。量子流体表现出“颗粒性”而不是连续行为，并且这种量子行为在减小的维度中被强调，因为“颗粒”尺寸增加。缩小的尺寸也将以其他方式被利用，以展示新型的超流体状态，这种状态可能会像旋转的陀螺一样显示出手性。通过结合低温和纳米制造，两名研究生和几名本科生将接触到令人兴奋的训练场，为科学家在学术界和高科技行业的领导角色做好准备。该项目将测试什么尺寸范围与从普通三维行为到二维行为的转换相关。