We combine theoretical insights and computational methods to explore the fundamental principles governing the quantum behavior of molecules, nanostructures, and materials. Our research emphasizes the use of unconventional theoretical frameworks, such as many-body Green’s functions and stochastic approaches, to develop innovative methods and physical approximations. These tools enable us to investigate electronic structures and dynamics in systems under non-equilibrium conditions, those driven by external stimuli, open quantum systems, chiral-induced phenomena, and beyond!