Magnetic Excitations in Magnetically Ordered Superfluids

磁有序超流体中的磁激发

• 批准号: 1405909
• 负责人: Dan Stamper-Kurn
• 金额: $ 38.2万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-15 至 2018-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1405909&HistoricalAwards=false
• 关键词: Magnetic; Excitations; Magnetically; Ordered; Superfluids; Magnetic; Excitations; Magnetically; Ordered; Superfluids

This project supports the study of a new kind of "superfluid" (a spinor Bose-Einstein condensate) which not only flows without resistance (one of the characteristics of superfluids) but also presents magnetic order (like a bar magnet). This superfluid is made up of an atomic gas that is cooled to extremely low temperatures and confined by a so-called "optical tweezer trap" (created by laser light) within a vacuum chamber. The researchers supported by this project will examine the magnetic characteristics of this gaseous material, and also clarify ways in which the magnetism and superfluidity of this material influence one another. The broader goal of this work is to help understand materials better, in particular those materials where the theory of quantum mechanics plays a dominant role (such materials can be expected to be increasingly put to use, particularly when they involve short length scales such as in the microelectronics industry). Toward this goal, the magnetic superfluid studied here is a useful test subject, one for which all of the basic physics underlying the material properties is believed to be known, and to which one can apply very precise and sensitive measurement techniques. The project will take place at a public University, and will support the training of graduate students in that setting.The project is focused on three specific aims. The first is to characterize magnons in magnetically ordered superfluids. These magnons are the elementary magnetic excitations of these materials. A variety of approaches, many based on directly imaging the propagation of magnon waves, will be used to measure the magnon energy, damping, magnetic moment, and nonlinearities, and also to clarify the role of long-range magnetic dipole interactions. The second aim of this project is to study the condensation of magnons within ferromagnetic superfluids, related to the phenomenon of magnon condensation in solid-state magnetic materials. The third aim is to study the influence of spatially varying magnetization (spin textures) on mass currents and spin currents. This work will study differences between the study of scalar superfluids and magnetically ordered superfluids, with the goal of identifying the basic processes in the hydrodynamics of spinor Bose-Einstein condensates (something one might call "superfluid magnetohydrodynamics").

该项目支持对一种新型的“超氟”（一种纺纱玻璃纤维冷凝物）的研究，该纺丝不仅流动而没有电阻（超氟的特征之一），而且还呈现磁性（如棒磁铁）。 这种超流体由一种原子气体组成，该原子气体被冷却至极低的温度，并由真空室内的所谓“光镊”（由激光灯创建）限制。 该项目支持的研究人员将检查这种气态材料的磁性特征，并阐明该材料磁性和超流量相互影响的方法。 这项工作的更广泛的目标是帮助更好地理解材料，特别是那些量子力学理论起主要作用的材料（可以期望越来越多地使用此类材料，尤其是当它们涉及短长度尺度（例如在微电子行业中）时。 为了实现这一目标，这里研究的磁性超流体是一个有用的测试主题，据信材料特性的所有基本物理学是已知的，并且可以采用非常精确和敏感的测量技术。 该项目将在公立大学举行，并将在该环境中支持研究生的培训。该项目集中在三个特定目标上。 首先是在磁有序的超流体中表征镁。 这些镁是这些材料的基本磁激发。 多种方法，许多基于直接成像的镁波的传播，将用于测量磁通能量，阻尼，磁矩和非线性，并阐明远程磁偶极相互作用的作用。 该项目的第二个目的是研究铁磁超流体中镁元素的凝结，这与固态磁性材料中木剂凝结现象有关。 第三个目的是研究空间变化的磁化（自旋纹理）对质量电流和自旋电流的影响。 这项工作将研究标量超流体研究和磁有序的超流体之间的差异，目的是识别纺纱子Bose-Einstein冷凝物流体力学中的基本过程（人们可能称之为“超氟磁铁氢动力学”）。