Time evolution and multiphoton ionization of Rydberg wavepacket in microwave fields

We present a theoretical study of the time evolution of Rydberg wavepacket, initially localized in radial space and mimicking the classical particle, undergoing microwave multiphoton ionization. The dynamical behavior of the Rydberg wavepacket is found to be different from that of Rydberg atoms initially prepared at given Rydberg eigenstates. It is seen that the Rydberg wavepacket can exhibit collapse and revival behavior in the short time regime. Further, both the microwave ionization rates and the quantum phase space trajectories of the Rydberg wavepackets exhibit qualitatively different behavior in small scaled-frequency (ωs (≡ ωn03) ≪ 1.0) and large scaled-frequency (ωs ⩾ 1.0) regimes.