2025/03/31 by Bruhnke, Jakob Nicolai, Olofsson, Edvin, Stenquist, Axel +1
#FOS: Physical sciences #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.2503.24038
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 can be of similar amplitude as the elementary femtosecond Rabi oscillations between the two strongly coupled states. The effect, which is beyond the two-level atom, is non-reciprocal: It only affects the excited state, while the ground state is unaffected. We propose that two-photon Rabi oscillations (1s2-1s3d) in helium is suitable for the generation of this type of ultrastrong coupling with realistic pulses. We use a combination of Floquet theory and effective Hamiltonian theory to test our predictions against ab initio simulations.