Real-time quantum many-body dynamics

Abstract

Solutions to the time-dependent Schrödinger equation are central to the understanding of the interaction between particles and external probes. The increasing availability of intense laser fields in experiments has spawned an interest in the study of the dynamics of many-body systems interacting with strong laser pulses. However, the complexity of the many-body problem quickly becomes a significant roadblock in the exploration of larger atoms and molecules, thus limiting the size of the systems that can be explored. Real-time ab initio electronic structure theory provides promising methods for investigating the dynamics of matter-field interactions and we have implemented several many-body methods which we use to analyze atoms and molecules subject to intense laser fields. We implement three different ab initio real-time methods: Hartree-Fock, configuration interaction, and coupled-cluster which we apply to systems of atoms and molecules. A thorough theory section outlines the foundation of our work. We demonstrate the strengths of the implemented methods and highlight the applicability of the orbital-adaptive time-dependent coupled-cluster method with doubles excitations by showcasing how this method is stable where the more conventional time-dependent coupled-cluster method with singles-and-doubles excitations fail. We demonstrate the first dipole allowed transition energy for Neon and Argon in the aug-cc-pVDZ basis to be 19.4327 eV and 12.7275 eV, respectively. Finally, we end this thesis demonstrating the versatility of our implemented methods by exhibiting simulations of exotic systems with spin-dependent laser fields and ionization of the one-dimensional Beryllium atom.