Search for Bose-Einstein Condensation in Solid 'He'

在固体“He”中寻找玻色-爱因斯坦凝聚

• 批准号: 9802046
• 负责人: John Goodkind
• 金额: $ 4万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-15 至 2001-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9802046&HistoricalAwards=false
• 关键词: Search; Bose; Einstein; Condensation; Solid

9802046 Goodkind This is a low temperature physics project which deals with a recent discovery of some interesting anomalies in the propagation of sound in He-4 crystals containing small amounts of He-3. The anomalies involve the sound velocity and the acoustic attenuation at a temperature near 1 K and depend on the concentration of the He-3 impurity. A conjecture has been made that these anomalies can be explained on the basis of a Bose-Einstein condensation. The purpose of this project is to perform refined measurements to determine whether the anomalies give evidence for a new family of excitations which travel ballistically or in a second sound mode, and whether the observed phase transition is a truly Bose- Einstein condensation of these excitations. This project offers an opportunity for the training of graduate students in a forefront area of contemporary physics. %%% Research in low temperature physics has resulted in the discovery of a phenomenon called the Bose-Einstein condensation of elementary particles and, more recently, ultra cold atoms, an effect which was predicted in the 1920's. Still more recently, a discovery was made that in solid helium-4 (the most common variety of this element) a peculiar and as yet not understood behavior of the propagation of sound and its attenuation takes place when the solid contains a small amount of the light isotope helium-3 as an impurity. There is no accepted explanation available for this anomalous behavior and a suggestion that the observed phenomenon is due to a Bose-Einstein condensation is met with skepticism. The proposed research is designed to provide more accurate and detailed data which will allow a definitive interpretation of the anomaly. The resolution of this problem is of fundamental importance to the physics of condensed matter. This project offers an opportunity for the trainin g of graduate students in a forefront area of contemporary physics. ***

小行星9802046 这是一个低温物理项目，涉及最近发现的含有少量He-3的He-4晶体中声音传播的一些有趣的异常现象。 异常涉及声速和声衰减在1 K附近的温度和依赖于He-3杂质的浓度。 有人猜想这些反常现象可以用玻色-爱因斯坦凝聚来解释。 该项目的目的是进行精确的测量，以确定异常是否为弹道传播或以第二声音模式传播的新激发族提供证据，以及观察到的相变是否是这些激发的真正玻色-爱因斯坦凝聚。该项目为当代物理学前沿领域的研究生培训提供了机会。 %低温物理学的研究发现了 一种叫做玻色-爱因斯坦凝聚的现象 基本粒子和最近的超冷原子，这是在20世纪20年代预测的效果。最近，人们发现，在固体氦-4（这种元素最常见的种类）中，当固体中含有少量轻同位素氦-3作为杂质时，会发生一种特殊的、至今尚未被理解的声音传播及其衰减行为。 对于这种反常的行为，目前还没有公认的解释，有人认为观察到的现象是由于玻色-爱因斯坦凝聚引起的，这一点受到了怀疑。 拟议的研究旨在提供更准确和详细的数据，以便对异常进行明确的解释。 这个问题的解决对凝聚态物理学具有根本的重要性。 这个项目为培养当代物理学前沿领域的研究生提供子一个机会。 ***