Manipulating a Rydberg electron in a classical orbit

When applying to a Rydberg atom a weak microwave (MW) field whose frequency nearly matches the classical Kepler frequency of the electron, a spatially localized potential well which oscillates in phase with the MW field is produced in the atom due to a combination of Coulomb potential and an external MW field, in which the electron probability distribution is trapped for a long time: An “eternal” non-dispersing wave packet is created which resembles a classical atom since localized wave packet does not manifest dispersion as time evolves and thus follows Ehrenfest’s theorem. By exploiting the synchronization of the electron wave packet with the MW field, which can be said as phase locking of electron’s radial motion based on the corresponding classical dynamics of nonlinear resonance island in phase space, we have demonstrated that the electron’s orbital motion is sped up or slowed down by increasing or decreasing the MW frequency.