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发挥着关键作用。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、大气物理和辐射损伤。世界各地的几个实验小组正在对涉及正电子素的碰撞进行密集的研究。正电子素是最简单的物质-反物质原子，由电子和正电子组成。在我们的宇宙中，为什么物质主导于反物质，这个大问题的答案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原子的碰撞来完成。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来源。本项目将包括对涉及电子、正电子和正电子原子的碰撞及其受激光场控制的理论研究。它将对反物质的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。对研究生的指导将促进他们在不同物理领域的培养。将使用各种经典、半经典和量子方法从理论上研究电子和正电子(Ps)与原子、分子、质子和反质子的碰撞。这些研究将被激光辅助的电子和Ps碰撞的研究所补充，特别是在ps与质子和反质子的碰撞中，激光辅助的辐射复合、解离复合、Ps的形成和电荷转移。在电子和Ps与质子的碰撞领域，该项目将侧重于发展经典和半经典方法，这在以前的计算中是合理的。PS-分子碰撞将使用具有描述交换和关联的正交性约束的自由电子-气体模型进行量子力学处理。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.