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

*理解超流体对智力的影响他在物理学的许多领域都有涉猎。这项提议资助的计划将把纳米流体领域与低温物理结合起来，以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。它们将表征允许流体锁定到表面或在表面滑动所需的表面粗糙度。表面粗糙度也应该给量子流体增加可量化的无序。在计划中的实验中，将检查限制对相图的影响，以期揭示新的(甚至可能是手性的或手性的)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培训场地，为科学家在学术界和高科技行业担任领导角色做好准备。这项拟议的研究将揭示超流有序参数在限制下的稳定性，并在超流消失的量子相变过程中寻找受限制的新形式的超流。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度中。*非技术摘要*我们的许多日常设备(比如手机、电脑)都源于凝聚态研究带来的根本性进步。反过来，未来的进展将取决于对目前只能在实验室环境中获得的新制度的探索。在这个项目中进行的研究将检验超流3He在小于千分之一毫米高的超小型工程腔中的特殊性质，标志着从整体三维行为到新的二维区域的转变。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“恰到好处”就会被锁定在表面。通过研究流体，研究人员希望更好地理解量子流体(相对于经典流体)是如何彼此不同的。量子流体表现出一种“颗粒状”而不是连续的行为，这种量子行为在降维时被强调，因为“颗粒”的尺寸增加了。缩小的尺寸还将被用于其他方式，以展示新型超流体状态，这些状态可能表现出惯用左手的行为，比如旋转的顶部。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培训场地，为科学家在学术界和高科技行业担任领导角色做好准备。该项目将测试什么大小范围是相关的转换从普通的3维行为到2维行为。

****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.