Giant counter-rotating oscillations on the attosecond timescale
We predict an unexplored type of ultrastrong coupling between atoms and intense ultraviolet light that leads to giant population oscillations on the attosecond timescale. These counter-rotating oscillations stem from the interference of energy-conserving and nonconserving photon absorption and emission processes via Rydberg states. They can be of similar amplitude as the elementary femtosecond Rab
