Laser-Assisted Electron and Positronium Collisions

低能电子及其反粒子正电子在许多环境和许多基本过程中起着关键作用。涉及这些粒子的碰撞在许多应用领域都很重要，包括技术等离子体，天体物理学，大气物理学和辐射损伤。正电子素是由电子和正电子组成的最简单的物质-反物质原子，它的碰撞正在世界各地的几个实验组中进行紧张的研究。要回答为什么在我们的宇宙中物质比反物质占主导地位这个大问题，需要对最简单的反物质原子反氢进行研究。反氢原子的产生可以通过反质子与正电子素原子碰撞来完成。这些过程目前正在大型强子对撞机上进行研究，该对撞机提供了强大的反质子源。本项目将包括电子、正电子和正电子素原子碰撞及其激光场控制的理论研究。它将对反物质基本性质的研究产生影响。该提案涉及跨学科努力和国际合作。研究生的指导将促进他们在物理学的不同领域的培养。各种经典，半经典和量子方法将被用来从理论上研究电子和正电子素（Ps）与原子，分子，质子和反质子的碰撞。这些研究将补充调查的激光辅助电子和Ps碰撞，特别是激光辅助辐射复合，解离复合，Ps的形成，并在Ps与质子和反质子碰撞的电荷转移。在电子和Ps与质子碰撞领域，该项目将侧重于发展经典和半经典方法，这些方法在以前的计算中是合理的。PS-分子碰撞将被处理量子力学与自由电子气模型的使用正交约束的交换和相关性的描述。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Low-energy electrons and their antiparticles, positrons, play a critical role in many environments and many fundamental processes. Collisions involving these particles are important in many applied fields including technological plasmas, astrophysics, atmospheric physics, and radiation damage. Collisions involving positronium, the simplest matter-antimatter atom consisting of electron and positron, are under intense studies in several experimental groups around the world. Answers to the big question why matter dominates over antimatter in our universe require studies involving the simplest antimatter atom, antihydrogen. Creation of antihydrogen atoms can be accomplished by colliding antiprotons with positronium atoms. These processes are currently investigated at the Large Hadron Collider, which provides the powerful source of antiprotons. The present project will include theoretical studies of collisions involving electrons, positrons and positronium atoms and their control by laser fields. It will have impact in studies of fundamental properties of antimatter. The proposal involves interdisciplinary efforts and international collaborations. Supervision of graduate students will promote their training in diverse areas of physics.A variety of classical, semiclassical and quantum methods will be employed to study theoretically electron and positronium (Ps) collisions with atoms, molecules, protons and antiprotons. These studies will be supplemented by investigation of laser-assisted electron and Ps collisions, particularly laser-assisted radiative recombination, dissociative recombination, Ps formation, and charge transfer in Ps collisions with protons and antiprotons. In the area of electron and Ps collisions with protons the project will focus on development of classical and semiclassical methods which were justified in previous calculations. Ps-molecule collisions will be treated quantum-mechanically with the use of free-electron-gas model with orthogonality constraints for description of exchange and correlations.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.