Classical Aspects of Wavepacket Dynamics

F. B. Dunning, Carlos O Reinhold, S. Yoshida +1 more

We describe how, almost 100 years after the introduction of the Bohr model of the atom, it is now possible using pulsed electric fields to create localized wavepackets in high n (n≈300) Rydberg atoms that travel in near-circular Bohr-like orbits mimicking the behavior of a classical electron. The protocols employed are explained with the aid of quantum and classical dynamics. Although many aspects of the underlying behavior can be described using classical arguments, purely quantum effects such as revivals can be seen even for n≈300.

Z. D. Gaeta, Carlos R. Stroud

We study the dynamics of a circular-orbit wave packet1 and find that it has both classical and quantum features. A circular-orbit wave packet consists of aligned, standard hydrogenic eigenstates of maximum angular momentum (l = in = n − 1), superimposed with a Gaussian weighting function. We calculate the uncertainty products in all three degrees of freedom and find that, as the quantum numbers of the constituent eigenstates increase, the uncertainty products tend toward h/2. The classical aspect of the dynamics displays itself during revivals, when a well-localized wave packet travels along a Kepler orbit, obeying the classical equations of motion. Spreading and revivals (including fractional revivals2) of the wave packet, which are manifestations of its quantum nature, are related to the nonlinearity of the hydrogen atom Hamiltonian. We study fractional revivals of the wavepacket in detail.

Huyen Nguyen, John Lekner

D. R. Meacher, P. E. Meyler, Ifan G. Hughes +1 more

The authors have excited and detected a radially localized electronic wavepacket in atomic rubidium. The wavepacket is formed of an optically induced coherent superposition of Rydberg states with mean principal quantum number, n=62. The motion of the wavepacket on a classical trajectory is monitored in a time-delayed ionization experiment. The collapse and revival of the classical dynamics is observed. During the period of nonclassical behaviour they observe, for the first time, a partial revival of the wavepacket.