Two-Dimensional Quantum Turbulence in Bose-Einstein Condensates

散装流体中的流体动力湍流与限于二维流体中的流体动力湍流的区别在于，后者在小长度尺度上的能量耗散通常受到抑制。在能量和涡度进入二维流体的小尺度强迫下，能量因此向更大的尺度转移，与散装流体中的湍流相反。最明显的是，这意味着涡流和涡流可能合并形成更大的涡流。二维量子湍流（2DQT）涉及对原子玻色-爱因斯坦凝聚（BECs）等量子流体中的二维湍流的研究。在这个新兴的研究领域中，许多悬而未决的问题通常与超流体中量化漩涡的动力学以及动能在长度尺度上的分布有关。例如，是否会像Onsager在1949年最初预测的那样，在2DQT流动中自然出现相同循环的量子化涡簇？该NSF奖支持旨在理解2DQT中涡分布、涡动力学和能谱之间关系的新实验。针对这些主题的实验研究计划将利用高度扁平的BEC构建一个新的成像系统，用于观察BEC内的涡动力学，开发按需涡生成和操作方法，以自下而上的方法研究湍流中的涡相互作用，以及研究和表征已开发的BECs中的2DQT。像稀气玻色-爱因斯坦凝聚体这样的超流体具有非凡的特性，包括无摩擦流动和只有通过形成许多被称为漩涡的微观量子漩涡才能获得的流体循环。这些涡旋在整个超流体中的分布和动力学为湍流等流体现象提供了信息。本项目研究量子涡旋的产生，并跟踪其在煎饼状凝析物中的动力学，作为理解超流体中二维湍流特性的一种手段。众所周知，经典流体中的湍流与超流体中的量子湍流有相似之处，但对于二维流动的具体情况，量子和经典情况之间的异同尚不清楚。这项拨款支持研究和研究生的指导和培训，涉及在冷凝物中创建、操纵和检测量子漩涡的新方法，并探测这些超流体中的二维湍流的特征。通过对二维量子湍流的控制研究，我们的目标是开发涡旋相互作用和其他湍流现象的新见解，这是物理学中最具挑战性和最复杂的主题之一。

A distinction between hydrodynamic turbulence in a bulk fluid, and in one whose flows are restricted to two dimensions, is that energy dissipation at small length scales is generally inhibited in the latter. Under small-length-scale forcing of energy and vorticity into a two-dimensional (2D) fluid, energy is therefore transferred towards larger scales, opposite that of turbulence in a bulk fluid. Most conspicuously, this means that eddies and vortices may merge to form even larger vortices. Two-dimensional quantum turbulence (2DQT) involves the study of 2D turbulence in quantum fluids such as atomic Bose-Einstein condensates (BECs). In this emerging field of research, numerous open questions generally relate to the dynamics of quantized vortices in superfluids and to the distribution of kinetic energy among length scales. For example, do clusters of quantized vortices of identical circulation naturally emerge in 2DQT flows, as initially predicted by Onsager in 1949? This NSF award supports new experiments aimed at understanding the relationships between vortex distributions, vortex dynamics, and energy spectra in 2DQT. The experimental program of research targeting these topics will utilize highly oblate BECs for the construction of a new imaging system designed to observe vortex dynamics within a BEC, the development of on-demand vortex generation and manipulation methods to study vortex interactions in turbulence with a bottom-up approach, and the study and characterization of developed 2DQT in BECs.Superfluids such as dilute-gas Bose-Einstein condensates have remarkable properties, including frictionless flow and fluid circulation that is obtained only by the formation of many microscopic quantum whirlpools known as vortices. The distribution and dynamics of these vortices throughout the superfluid provide information on fluid phenomena such as turbulence. This project is studying the generation of quantum vortices and follows their dynamics in pancake-shaped condensates as a means to understand the characteristics of two-dimensional turbulence in superfluids. Turbulence in classical fluids is known to share similarities with quantum turbulence in superfluids, but for the specific case of two-dimensional flows, the similarities and differences between the quantum and classical cases are unclear. This grant supports research and graduate-student mentoring and training involving new methods of creating, manipulating, and detecting quantum vortices in condensates, and probes the characteristics of two-dimensional turbulence in these superfluids. Through controlled studies of two-dimensional quantum turbulence, our aim is to develop new insights on vortex interactions and other phenomena of turbulence, one of the most challenging and complex topics in physics.