This talk will present our research on dark matter properties and dark matter search based on theoretical atomic, molecular, and optical (AMO) physics tools. We apply AMO physics’ theoretical tools to high-energy physics and cosmology scenarios. To illustrate our approach, first, we will present our work toward molecular excitations as light-dark matter detectors . Second, within the self-interacting dark matter paradigm, we will study chemical reactions between dark matter particles leading to dark molecules, focusing on three-body recombination , i.e., three free particles collide to form a bound state between two, whereas the third streams out freely. Finally, we will present some preliminary results on axion stars' stability and ground state properties by using quantum Monte Carlo techniques instead of the traditional mean-field approach of the Gross-Pitaevskii equation.