Controlling vortex rings in Bose--Einstein condensates

这个项目已经产生了新的软件来模拟各种物理系统，重点是超流体玻色-爱因斯坦凝聚体(BEC)及其超流体动力学。特别是，它开发了GPUE，即带有图形处理单元的Gross-Pitaevskii方程求解器，可用于各种物理系统。通过动态表达式树语法分析，用户可以将他们想要求解的任何方程输入到系统中，这些方程将通过伪谱分步傅立叶方法求解。今年的大部分工作都花在了模拟一个特定的系统上，其中一个环形超流体BEC被困在一根纳米光纤上。该系统允许通过利用锥形纳米光纤产生人工磁场来创建、控制和检测超流体涡旋结构。这是第一次以这种方式产生涡环和涡环状结构，这项研究应该允许未来的几项研究真正查明超流体涡旋如何以及为什么在湍流系统中发挥作用。总体而言，今年在初步完成该项目设定的目标方面取得了成功。

This project has resulted in novel software to simulate a variety of physical systems, with a focus on superfluid Bose--Einstein Condensates (BECs) and their superfluid dynamics. In particular, it has developed GPUE, the Gross-Pitaevskii Equation solver with Graphics Processing Units, which can be used for a huge variety of physical systems. With dynamic expression tree syntax parsing, users can input whatever equations they would like to solve into the system, and these will be solved via the pseudo-spectral split-step Fourier method.A large portion of this year's work went into simulating a particular system where a toroidal superfluid BEC is trapped around an optical nanofiber. This system allows for the creation, control, and detection of superfluid vortex structures via the generation of artificial magnetic fields with a tapered optical nanofiber. This is the first time vortex rings and vortes ring-like structures have been generated in this way and this study should allow for several future studies to really pinpoint how and why superfluid vortices act as they do in turbulent systems.Overall, this year has been successful in finishing up the goals set out by this project initially.