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

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During the last years numerous laboratories worldwide have begun to develop high-powered laser systems to create electromagnetic radiation pulses that are so energetic that new avenues to probe and control the states of matter can be tested soon. The research team at Illinois State University plans to accompany these developments with ab initio computer simulations that can provide microscopic insight into the relativistic interaction of electrons and positrons with photons with full temporal as well as spatial resolution. 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 and also at the XSEDE supercomputer cluster in Texas. A specific goal of the current grant is to simulate for the first time the laser-field induced electron-positron pair-creation process for a general situation for which the attractive Coulomb force between the two created particles is taken into account. Preliminary simulations for simplified model systems suggest that our present theoretical understanding of this process might need to be revised as this (so far neglected) inter-particle force might play a major role for the dynamics.