Quantum Vortex Laboratory: Generation, Manipulation, Imaging, and Dynamics of Vortices in Bose-Einstein Condensates

在高速下，流过物体或通过管道的流体会导致湍流，这是一种以不可预测的涡流或漩涡运动为特征的混乱状态。 湍流是普遍存在的，通常在飞机或船只中经历，在湍急的河流中观察到，并且可能存在于血液流动中。 然而，尽管对湍流的研究已经进行了几个世纪，但这种流体流动状态是物理学中最不了解的现象之一。发现其物理起源，并充分表征其动力学以及光滑和湍流之间的过渡，仍然是物理学中的重大挑战。 克服其中一些问题对于更深入地了解我们宇宙的许多方面是如何演变的至关重要。 这个NSF资助的项目实验性地解决了与一种特殊类型流体中的湍流相关的流体流动方面的问题，为此已经开发了理论和分析方法。 在这些被称为玻色-爱因斯坦凝聚物（BEC）的流体中，微观气体液滴冷却到绝对零度以上数十亿分之一度的温度，激光可以精确地产生，操纵和观察湍流以及包含湍流的涡旋的动力学。 通过测试理论预测，该项目推动了我们对BEC中出现的这些流体动力学特征的理解，推进了对湍流的理解，这些湍流是从物理学家用来描述宇宙，其结构和动力学的最基本框架中建立起来的。该项目的主要科学目标是发展对BEC中量子化涡旋动力学的完整理解，量子力学控制流体流动动力学的超流体。 为实现这一目标，采取了多方面的办法。 首先，该项目建立在以前的工作，以构建一个国家的最先进的显微镜设计，并致力于观察和测量涡流和他们的动态直接在BEC。 其次，在一个二维BEC的湍流过渡研究检查涡的产生BEC被激光搅拌。 结果测试关键的理论结果，并帮助建立量子和经典流体之间的联系。 第三，在BEC中按需创建和操纵涡流的工具包的构建继续进行，建立在以前成功的方法的基础上，这些方法使用移动激光束来生成和操纵涡流，以便可以在量子流体动力学实验中按需创建和使用特定的涡流布置或流体流动类型。 最后，新观察到的方法，涡核检查，以更全面地了解如何涡和湍流的流体流动可以产生BEC。 通过探索BEC涡旋的动力学，这项工作推进了对具有巨大不同微观特性的系统中的量子多体现象的更广泛理解，例如超流体，超导体和中子星的核心。 该项目依靠并促进对学生的科学教育和技术培训，这是保持国家科学实力、社会广度和创造力的关键。

At high speeds, fluid flow past an object or through a tube results in turbulence, a chaotic state of flow characterized by unpredictable motion of the vortices or eddies of the flow. Turbulence is ubiquitous, commonly experienced in aircraft or watercraft, observed in rushing rivers, and may be present in blood flow. Yet despite centuries of research on turbulence, this state of fluid flow is one of the least understood phenomena in physics. Discovering its physical origins, and fully characterizing its dynamics and the transition between smooth and turbulent flows, remain significant challenges in physics. Overcoming some of these problems is essential for reaching a deeper understanding of how numerous aspects of our universe evolve. This NSF-funded project experimentally tackles aspects of fluid flows related to turbulence in a special type of fluid for which theoretical and analytical approaches have been developed. In these fluids, called Bose-Einstein condensates (BECs), microscopic droplets of gases cooled to temperatures of a few billionths of a degree above absolute zero, laser light can precisely generate, manipulate, and observe turbulence and the dynamics of the vortices that comprise turbulence. By testing theoretical predictions, this project pushes the boundaries of our understanding of these features of fluid dynamics as they appear in BECs, advancing an understanding of turbulence built up from the most fundamental framework that physicists use to describe the universe, its structure, and its dynamics.The primary scientific aim of this project is the development of a complete understanding of quantized vortex dynamics in BECs, superfluids for which quantum mechanics governs the dynamics of fluid flow. To achieve this aim, a multi-faceted approach is pursued. First, the project builds on previous work to construct a state-of-the-art microscope designed for and dedicated to observing and measuring vortices and their dynamics directly in BECs. Second, the transition to turbulence in a two-dimensional BEC is studied by examining vortex generation as BECs are stirred by laser light. Results test key theoretical results, and help establish links between quantum and classical fluids. Third, the construction of a toolkit for on-demand creation and manipulation of vortices in a BEC is continued, building on previous successful methods that use moving laser beams to generate and manipulate vortices so that specific arrangements of vortices or types of fluid flow can be created and used on-demand in quantum fluid dynamics experiments. Finally, newly observed methods of vortex nucleation are examined in order to more fully round out an understanding of how vortices and turbulent fluid flows can be generated in BECs. By exploring the dynamics of BEC vortices, this work advances a broader understanding of quantum many-body phenomena in systems with vastly different microscopic properties, such as superfluids, superconductors, and the cores of neutron stars. The project relies on and promotes the scientific education and technical training of students, keys to maintaining national scientific strength and societal breadth and creativity.