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****理解超流体3He的智力影响延伸到物理学的许多领域。该提案资助的项目将把纳米流体领域与低温物理学结合起来，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传输的影响。它们将表征允许流体锁定在表面或在表面滑动所需的表面粗糙度。表面粗糙度还应该给量子流体增加可量化的无序性。在计划的实验中，将检查限制对相图的影响，以期揭示新的（可能是均匀手性或手性）相。 3He 的可压缩性将允许相干长度的长度尺度进行压力调节。通过将低温和纳米制造相结合，两名研究生和几名本科生将接触到令人兴奋的训练场，该训练场为科学家在学术界和高科技行业发挥领导作用做好了准备。拟议的研究将揭示超流体序参数在约束下的稳定性，并在约束下寻找超流体的新形式，以实现超流性消失的量子相变。这种新的超流体可能会引起量子计算和新型涡量的兴趣。 ****非技术摘要****我们的许多日常设备（例如手机、电脑）都源于凝聚态物质研究带来的基础性进步。反过来，未来的进步将依赖于对目前只能在实验室环境中实现的新机制的探索。该项目将进行的研究将检验超流体 3He 在被限制在高度不到千分之一毫米的超小型工程空腔中时的特殊性质，标志着从大块 3 维行为到新的 2 维状态的转变。这些空腔中的氦气流动应受表面粗糙度的支配，如果表面太光滑，氦气会滑移，或者如果粗糙度“恰到好处”，氦气会被锁定在表面上。通过检查流动，研究人员希望更好地了解量子（与经典）流体之间有何不同。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尺寸减小时得到强调，因为“颗粒”尺寸增加。减小的尺寸还将以其他方式利用来展示新型超流体状态，这些状态可能会像旋转的陀螺一样表现出旋手性。通过将低温和纳米制造相结合，两名研究生和几名本科生将接触到令人兴奋的训练场，该训练场为科学家在学术界和高科技行业发挥领导作用做好了准备。该项目将测试什么尺寸范围与从普通 3 维行为到 2 维行为的转换相关。