Quasiparticle spectra from molecules to bulk with stochastic many-body methods

I will present new developments in the stochastic approaches to electronic structure and many-body perturbation theory, which overcome steep scaling of conventional deterministic schemes. I will exemplify on calculations for systems with more than 5000 valence electrons and show evolution of photoemission spectra, quasiparticle energies, lifetimes and emergence of collective excitations (plasmons and shake-up) for systems ranging from molecules to bulk-like nanoparticles. The results demonstrate how the surface plasmon resonances affect the frequency of the collective excitation and position of the satellites in the spectra for small and low dimensional systems.