RUI: Path Integrals and Charged Particle Dynamics

RUI：路径积分和带电粒子动力学

• 批准号: 1912093
• 负责人: Allison Harris
• 金额: $ 11.72万
• 依托单位: Board of Trustees of Illinois State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1912093&HistoricalAwards=false
• 关键词: RUI; Path; Integrals; Charged; Particle

Atomic collisions are a well-established method for probing the structure of atoms and molecules, as well as understanding the dynamics of how charged particles interact with matter. Due to their quantum mechanical nature, the particles involved in the collision must be modeled as matter waves, not as individual point particles. In the last decade, particles with unique waveforms have been created. These new matter waveforms (known as vortex waves or twisted particles) have properties that offer the opportunity for control and rotation of nanoparticles and improved resolution in electron microscopy, as well as the study of fundamental atomic properties, such as the magnetic moment and atomic transitions. Currently, there is a very limited understanding of how twisted particles interact with individual atoms or molecules. In order to realize the proposed applications, it is necessary to develop theoretical models that describe the particles' interaction with atoms at the most basic level. The researchers will develop and apply theoretical models to describe the physics of collisions between twisted particles and atoms in order to explain recently observed quantum phenomena and provide guidance for future experiments and applications. In addition to the science, another key aspect of the project is the inclusion of undergraduate students in cutting-edge research and the training of the next generation of physicists. Participation in this project provides students with valuable hands-on research experience through conceptual development of the models, as well as implementation and analysis. The students will also present their results at regional and national conferences, giving them a more global view of scientific research and encouraging them to pursue careers in STEM fields.The goals of the project will be accomplished through the development of two distinct computational models. All of the models will be designed for use on high performance computers and will be parallelized to improve efficiency. One of the models is based on the time-dependent Path Integral Quantum Trajectory (PIQTr) method that utilizes a Lagrangian approach to quantum mechanics. This model will be applied to phenomena such as electron capture, coherence, diffraction, tunneling, and quantum reflection. Application of the PIQTr model to higher dimensional systems will require the implementation of numerical techniques, such as adaptive stepsize, Monte Carlo integration, and boundary matching techniques. The results of the PIQTr model will provide a time-dependent analysis of collision processes allowing researchers to view the evolution of the interaction. A second model will be developed for the study of electron vortex beam collisions with atoms. This model will provide insight into orbital angular momentum transfer, as well as orientation and rotation effects that may occur during the collision process. A multipole expansion of the collision transition amplitude will yield information regarding potential selection rules or the possibility of state selectivity. The results of the electron vortex beam studies will be in the form of collision cross sections that can be used to provide guidance to experimentalists and others interested in applications of electron vortex beams.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

原子碰撞是探测原子和分子结构以及了解带电粒子如何与物质相互作用的动力学的一种行之有效的方法。 由于它们的量子力学性质，参与碰撞的粒子必须被建模为物质波，而不是单个的点粒子。 在过去的十年中，具有独特波形的粒子已经被创造出来。 这些新的物质波形（称为涡旋波或扭曲粒子）具有为控制和旋转纳米粒子和提高电子显微镜分辨率以及研究基本原子特性（如磁矩和原子跃迁）提供机会的特性。 目前，人们对扭曲粒子如何与单个原子或分子相互作用的理解非常有限。 为了实现所提出的应用，有必要发展在最基本水平上描述粒子与原子相互作用的理论模型。 研究人员将开发和应用理论模型来描述扭曲粒子和原子之间的碰撞物理，以解释最近观察到的量子现象，并为未来的实验和应用提供指导。 除了科学，该项目的另一个关键方面是将本科生纳入前沿研究和培养下一代物理学家。 参与这个项目为学生提供了宝贵的实践研究经验，通过模型的概念发展，以及实施和分析。 学生们还将在区域和国家会议上展示他们的成果，让他们对科学研究有更全球化的看法，并鼓励他们在STEM领域追求职业生涯。该项目的目标将通过开发两个不同的计算模型来实现。 所有模型都将设计用于高性能计算机，并将并行化以提高效率。 其中一个模型是基于时间相关的路径积分量子轨迹（PIQTr）方法，该方法利用拉格朗日方法来量子力学。 这个模型将被应用于现象，如电子捕获，相干性，衍射，隧穿和量子反射。 PIQTr模型应用于高维系统将需要实施的数值技术，如自适应步长，蒙特卡罗积分，边界匹配技术。 PIQTr模型的结果将提供碰撞过程的时间相关分析，使研究人员能够查看相互作用的演变。 第二个模型将被开发用于研究电子涡旋束与原子的碰撞。 这一模型将提供对轨道角动量转移以及碰撞过程中可能发生的定向和旋转效应的深入了解。 碰撞跃迁振幅的多极展开将产生关于潜在的选择规则或状态选择性的可能性的信息。 电子涡旋束研究的结果将以碰撞截面的形式呈现，可用于为实验者和其他对电子涡旋束应用感兴趣的人提供指导。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Control of arrival time using structured wave packets

• DOI: 10.1016/j.physleta.2020.127038
• 发表时间: 2020-07
• 期刊: Physics Letters A
• 影响因子: 2.6
• 作者: T. Saxton;A. Harris

Single and double scattering mechanisms in ionization of helium by electron vortex projectiles

电子涡流射弹电离氦的单散射和双散射机制

• DOI: 10.1088/1361-6455/ac1c38
• 发表时间: 2021
• 期刊: Molecular and Optical Physics
• 作者: Harris, A L

Projectile transverse momentum controls emission in electron vortex ionization collisions

• DOI: 10.1088/1361-6455/abb3ac
• 发表时间: 2020-07
• 期刊: Journal of Physics B: Atomic, Molecular and Optical Physics
• 作者: A. Plumadore;A. Harris

Electron spectra for twisted electron collisions

扭曲电子碰撞的电子能谱

• DOI: 10.1088/1361-6455/ac41b1
• 发表时间: 2021
• 期刊: Molecular and Optical Physics
• 作者: Plumadore, A;Harris, A L
• 通讯作者: Harris, A L

Projectile Coherence Effects in Twisted Electron Ionization of Helium

氦扭曲电子电离中的射弹相干效应

• DOI: 10.3390/atoms11050079
• 发表时间: 2023
• 期刊: Atoms
• 影响因子: 1.8
• 作者: Harris, A. L.