SGER: An Experiment to Understand the Apparent "Supersolid" Behavior of Solid 4He

SGER：了解固体 4He 表面“超固体”行为的实验

• 批准号: 0650092
• 负责人: Robert Hallock
• 金额: --
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-12-01 至 2009-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0650092&HistoricalAwards=false
• 关键词: SGER; Experiment; Understand; Apparent; Supersolid

********NON-TECHNICAL ABSTRACT*****Recently a startling discovery was announced: At very low temperatures and elevated pressures atoms of helium apparently flow though solid helium without friction. This announcement was startling because ordinary solids behave themselves and while atoms in a solid wiggle a bit, they generally stay put. It is common experience that when you pick up a rock, none of the solid leaks out. This Small Grant for Exploratory Research (SGER) will support a project that will, under a variety of temperatures and pressures, explore whether a pressure difference applied between two liquid helium reservoirs on either side of a block of solid helium will relax by the flow of atoms through the solid helium. The reservoirs on either side of the solid will be liquid, maintained in that state by the unique properties of helium in a highly porous material. If atoms do indeed flow through the solid, this research will help to determine the true mechanism by which this takes place. And, if such flow is present, other experiments will attempt to cause the flow to take place through a donut-shaped sample of solid helium and determine whether such flow is persistent - i.e. able to flow in a closed loop without slowing down. That is, the research will explore whether it is possible for there to be friction-free super-flow in a solid. The experiments are time-urgent since this area is extremely active; with groups around the world intensely pursuing different approaches in attempts to confirm the existence of this strange state. While ripe for discovery, such work is also risky, with some experiments to date yielding unexpected negative results. Confirming the existence of this strange solid would have a large impact our understanding of "quantum states of matter." Graduate students will be involved in the experiments and thus they will receive training that will lead to a Ph.D. and their eventual entry into the scientific workforce.******** TECHNICAL ABSTRACT*****This SGER supports research seeking to provide substantial insight into the true physics behind the startling observations of Kim and Chan seen in solid helium in which they observed a moment of inertia change in a torsional oscillator and interpreted the observation as evidence for a new state of matter, a "supersolid". The first experiments will place solid helium adjacent to helium contained in the porous material Vycor, by which it is possible to create a condition in which liquid helium can interface solid helium at pressures above the normal melting curve. The experiments will seek to establish whether a pressure difference imposed between the two fluid reservoirs on two sides of a cylinder of solid helium can relax by the flow of helium atoms through the solid and how such flow may vary with the base pressure of the solid. When completed, these experiments should shed considerable insight into the true nature of the "supersolid" and help to elucidate the specific mechanism by which such flow takes place. If such flow is detected with reasonable critical velocity, the next experiments will seek to establish a persistent flow in a torus-shaped geometry and document that the flow is indeed persistent. The experiments are time-urgent since this area is extremely active; with groups around the world intensely pursuing different approaches in attempts to confirm the existence of the "supersolid" state. While ripe for discovery, such work is also risky, with some experiments to date yielding unexpected negative results. Confirming the existence of a "supersolid" state would have a large impact on our understanding of quantum states of matter. Graduate students will be involved in the experiments and thus they will receive training that will lead to a Ph.D. and their eventual entry into the scientific workforce.

********非技术摘要*****最近宣布了一个惊人的发现：在非常低的温度下，氦气的压力升高显然是通过没有摩擦的固体氦气流动的。 这一宣布令人震惊，因为普通固体行为自己，而原子却稍微摆动，但它们通常会留下来。 普遍的经历是，当您拿起一块岩石时，没有一个固体泄漏。 这项用于探索性研究的小赠款（SGER）将支持一个项目，该项目将在各种温度和压力下探索是否在一个固体氦气块的两侧两侧施加了压力差，是否会因原子通过固体氦气而放松。 固体两侧的储层将是液体，通过在高度多孔材料中的独特特性来维持在该状态。如果原子确实确实流过固体，则该研究将有助于确定发生这种情况的真实机制。 而且，如果存在这种流动，其他实验将尝试通过固体氦的甜甜圈样品进行流动，并确定这种流程是否持续 - 即能够在闭环中流动而不会放慢速度。也就是说，研究将探讨是否有可能在固体中有无摩擦的超级流。由于该区域非常活跃，因此实验是静止的。随着世界各地的群体强烈采取不同的方法，试图确认这种奇怪的状态的存在。 虽然发现成熟，但这种工作也有风险，迄今为止，一些实验会产生意外的负面结果。 确认这种奇怪的固体的存在将产生很大的影响，我们对“物质量子状态”的理解。 研究生将参与实验，因此他们将获得将导致博士学位的培训。 ********技术摘要*****这项SGER支持寻求对Kim和Chan令人震惊的观察到的真实物理学的洞察力，在坚实的氦气中看到的真实物理学，他们观察到扭转振荡器中惯性变化的时刻，并将opperation的证据视为新的supersolid'supersolid'' 第一个实验将放置与多孔材料Vycor中氦气相邻的固体氦气，通过该氦气可以创建一个条件，在这种情况下，液态氦气可以在正常熔化曲线上方的压力下连接固体氦气。 该实验将寻求确定在固体氦气缸的两个侧面的两个流体储层之间施加的压力差是否可以通过氦原子的流动流过固体而放松，并且这种流量可能随固体的基本压力而变化。 完成后，这些实验应大量了解“ Supersolid”的真实本质，并有助于阐明发生这种流动的特定机制。 如果以合理的临界速度检测到这种流程，下一个实验将寻求在圆环形的几何形状中建立持续的流量，并记录流动确实持续存在的。 由于该区域非常活跃，因此实验是静止的。随着世界各地的群体强烈采取不同的方法，试图确认“超olid”状态的存在。 虽然发现成熟，但这种工作也有风险，迄今为止，一些实验会产生意外的负面结果。 确认存在“超olid”状态的存在将对我们对物质量子状态的理解产生重大影响。 研究生将参与实验，因此他们将获得将导致博士学位的培训。以及他们最终进入科学劳动力队伍。