Applications of the Ordered Phases of Helium Three to Broader Questions in Physics

9971694 Osheroff这是一个低温物理项目，涉及氦的丰度较低的同位素He-3。固态和液态He-3的低温有序相表现出复杂但非常容易理解和容易测量的物理性质，在许多情况下，这些性质模拟了在具有更大技术重要性的系统中不太清楚的行为。例如，人们可以很容易地从相邻磁畴的NMR谱的位移中观察到固体He-3的U2 D2自旋有序相中的反铁磁畴壁。这种能力将被利用在目前的研究计划，研究畴壁钉扎和流动性的反铁磁体干净的第一次。这些知识对于理解磁系统在介观尺度上的稳定性和宏观隧穿现象是有用的。在另一个例子中，p波3 He BCS超流基态将在Tc处无限简并，如果没有临界波动，则预测临界波动将稳定Tc附近的相位，这与在较低温度下看到的相位不同。本研究计划将探索这一区域的宽度，并试图确定Tc附近的有序相，从而为我们对临界现象理论的理解提供一个新的测试。该项目主要教育研究生，尽管物理专业也在实验室进行高级荣誉项目。谁追求低温研究的学生获得凝聚态物理和实验技术的严格和非常广泛的教育。这个低温物理项目将利用固体和液体He-3的低温相的许多独特性质来研究这些有序相的特定性质，这些有序相的物理起源与其他技术上更重要的材料中的性质相同，例如用于磁存储设备的材料。在一组实验中，将使用磁共振技术在固体3 He的磁有序相中研究具有不同取向的磁有序域之间的边界的性质和流动性。这项研究将涉及这样一个问题：一个系统如何以量子力学的方式穿过一个太高的势垒。第二项研究将涉及超流3 He，它表现出与传统超导体相似的有序相，但要复杂得多。超流性的本质就在有序状态的过渡之下，将被用于一个新的理论测试，该理论似乎成功地描述了所有的二阶或“连续”相变。这将为这一诺贝尔奖获奖理论的适用性和有效性提供一个独特的测试。该项目主要教育研究生，尽管物理专业也在实验室进行高级荣誉项目。谁追求低温研究的学生获得凝聚态物理和实验技术的严格和非常广泛的教育。***

9971694OsheroffThis is a low temperature physics project dealing with less abundant isotope of helium, He-3. The low temperature ordered phases of solid and liquid He-3 exhibit complex yet remarkably well understood and easily measured physical properties which in many instances mimic the behavior seen less clearly in systems with much greater technological importance. For instance, one can easily observe antiferromagnetic domain walls in the U2D2 spin ordered phase of solid He-3 from shifts in the NMR spectra of the adjacent magnetic domains. This ability will be utilized in the present research program to study domain wall pinning and mobility in an antiferromagnet cleanly for the first time. This knowledge should be useful in understanding the stability of magnetic systems on a mesoscopic scale, and macroscopic tunneling phenomena generally. In another example, the p-wave 3He BCS superfluid ground state would be infinitely degenerate at Tc were it not for critical fluctuations, which are predicted to stabilize phases near Tc which are different from those seen at lower temperatures. This research program will probe the width of this region, and attempt to identify the ordered phases near Tc, thus providing a new test of our understanding of the theory of critical phenomena. The project educates primarily graduate students, although physics majors carry out senior honors projects in the lab as well. Students who pursue low temperature studies obtain a rigorous and very broad education in condensed matter physics and experimental techniques. %%%This low temperature physics project will utilize many of the unique properties of the low temperature phases of solid and liquid He-3 to study specific properties of these ordered phases whose physical origins are common to properties seen in other more technologically important materials, such as those used in magnetic memory devices. In one set of experiments, the nature and mobility of the boundaries between magnetically ordered domains with different orientations will be studied in a magnetically ordered phase of solid 3He using magnetic resonance techniques. This study will bear on the question of how a system can quantum mechanically tunnel through a barrier which is too high for it to go over. A second study will involve superfluid 3He, which exhibits ordered phases similar to those seen in conventional superconductors, but much more complex. The nature of the superfluidity just below the transition to the ordered state will be used in a novel test of the theory which appears to successfully describe all second order, or 'continuous' phase transitions. This will provide a unique test of the applicability and validity of this Nobel prize winning theory. The project educates primarily graduate students, although physics majors carry out senior honors projects in the lab as well. Students who pursue low temperature studies obtain a rigorous and very broad education in condensed matter physics and experimental techniques. ***