WAVE PACKET DYNAMICS IN TWO-ELECTRON ATOMS: INFLUENCE OF A STRONGLY DRIVEN CORE RESONANCE

摘要: When a short laser pulse coherently excites a superposition of Rydberg states, a radial wave packet is formed. On a short time scale the wave packet obeys the laws of classical mechanics, as the center of the probability distribution oscillates between the inner and outer classical turning radius of the Kepler orbit. In the limit of high effective radial quantum number v, the period of this motion agrees with the semiclassical orbit time Ta (au)= 2π³ (eg 19 ps for v= 50) calculated from the binding energy W,(au)=-1/(22). As time evolves the wave packet spreads on a time scale determined by the spread in radial linear momentum [14, 2].The dynamics of wave packets of electrons bound to atoms [2] or more general potentials [11, 20, 3] is an important current topic. We consider a relatively simple problem: A wave packet orbits the structured core of a two-electron atom being manipulated by an external field. Despite the simplicity, the setup represents a quantum zoo in itself where many interesting and rare species can be studied at close-up distance: These include the correspondence principle, interference and entanglements of the classical position of one electron with the quantum state of another. From a more pragmatic point of view, the results are very interesting as they represent a realistic method of controlling wave packet dynamics.