RUI: Spatial and Temporal Dynamics of Matter in Intense Laser Fields

世界各地的实验室已经开始开发高功率激光系统，这种系统可以产生能量如此之高的电磁辐射脉冲，从而开辟了新的探索途径。这个项目将通过从头计算计算机模拟来帮助这些令人兴奋的发展，这些计算机模拟具有足够的时间和空间分辨率，以提供对光子与电子和正电子的相对论相互作用的微观洞察。对这些基本过程的更好理解可能会为在很短的时间尺度上控制原子、化学甚至生物过程开辟新的途径。助学金的一项重要使命也是让本科生有机会获得研究经验。这种教育经验为他们提供了重要的技能，包括团队合作，获得解决严重研究问题的耐力、智力灵活性和经验，以及在会议和出版物中交流结果。计算机模拟是通过在数值时空网格上求解相对论量子电动力学的耦合Dirac-Maxwell方程组来获得的。这些非扰动的大规模计算非常耗费CPU时间，但由于用于大规模并行计算机的专用数值算法的最新进展，这些计算已经成为可能。计算是在伊利诺伊州进行的。这项工作的一些主要目标包括通过合适的激光场设计优化对子产生，开发更有效的一般相对论相互作用方法，利用几种物理机制来降低对子产生所需的激光强度，并提供一种新的诊断技术来监测反应区内的产生动力学。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。

Laboratories across the world have begun to develop high-powered laser systems which can create electromagnetic radiation pulses that are so energetic that they open new avenues of exploration. This project will assist these exciting developments with ab initio computer simulations which have sufficient temporal and spatial resolution to provide microscopic insight into the relativistic interaction of photons with electrons and positrons. A better understanding of these fundamental processes might open new ways to control atomic, chemical and even biological processes on very short time scales. An important mission for the grant is also to give undergraduate students the opportunity to gain research experience. This educational experience provides them with important skills including working as a team, gaining the endurance, intellectual flexibility and experience to tackle serious research problems, and communicating results in conferences and publications.The computer simulations are obtained by solving the coupled set of Dirac-Maxwell equations of relativistic quantum electrodynamics on a numerical space-time grid. These non-perturbative large-scale calculations are very CPU time consuming but have become possible due to recent progress in the development of specialized numerical algorithms for massively parallel computers. The calculations are performed in Illinois. Some of the primary goals of the work include optimizing the pair creation yield by suitable laser field designs, developing more efficient approaches for general relativistic interactions, exploiting several physical mechanisms to lower the laser intensity required for pair-creation and providing a new diagnostic technique to monitor the creation dynamics inside the reaction zone.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.