This talk summarizes studies of condensed-matter electronic systems and the radiation field in situations where their dimensions are confined to scales below the wavelength and/or oscillation cycles of elementary excitations. First, few fermions in individual semiconductor quantum dots are investigated. Here, full spatial confinement and the Pauli principle lead to quantum phenomena far from equilibrium such as coherence transfer in exciton-phonon interaction and persistent quantum beats of hot trion states [1]. The second part introduces the concept of transient Wannier-Stark localization. A two-dimensional character of the electronic system of a bulk semiconductor emerges under subcycle biasing with mid-infrared fields of intramolecular strength [2]. Next, the attosecond transport of single electrons is controlled with phase-locked single-cycle pulses in the near infrared applied to plasmonic nanoantennas [3]. At present, we are reducing these structures to the atomic scale. Finally, the status of our efforts is presented to establish and analyze time-domain quantum electrodynamics based on ultrabroadband electro-optic sampling in theory and experiment [4,5].