Two-level system on-resonance driven at Ω_R = |⟨e|d·E|g⟩|/ℏ oscillates between levels; basis of coherent control, qubit gates.
Two-level system on-resonance driven at Ω_R = |⟨e|d·E|g⟩|/ℏ oscillates between levels; basis of coherent control, qubit gates.