Formation of cold molecules by shaping with light the short-range interaction between cold atoms: photoassociation with strong laser pulses

Abstract

The paper investigates cold molecules formation in the photoassociation of two cold atoms by a strong laser pulse applied at short interatomic distances, which lead to a molecular dynamics taking place in the light-induced (adiabatic) potentials.A two electronic states model in the cesium dimer is used to analyse the effects of this strong coupling regime and to show specific results: i) acceleration of the ground state population to the inner zone due to a non-impulsive regime of coupling at short and intermediate interatomic distances; ii) formation of cold molecules in strongly bound levels of the ground state, where the population at the end of the pulse is much bigger than the population photoassociated in bound levels of the excited state; iii) the final momentum distribution of the ground state wavepacket keeping the signatures of the maxima in the initial wavefunction continuum. It is shown that the topology of the light-induced potentials plays an important role in dynamics.

Measures of electronic-vibrational entanglement and quantum coherence in a molecular system

“…The process is represented in Fig. 1, the electronic curves being those described in [42]. We suppose a chirped pulse with the envelope f (t) centered at t P = 15 ps, and temporal width τ C = 2.1 ps (represented in Fig.…”

Non-Markovian dynamics of the electronic subsystem in a laser-driven molecule: Characterization and connections with electronic-vibrational entanglement and electronic coherence

“…1), couples the two electronic states activating a vibrational dynamics which involves several vibrational levels of each surface, with vibrational periods of about 11 ps in the 1 g electronic potential (the vibrational levels v e = 140 up to 143 are implied), and between 33 and more than 100 ps in the a 3 Σ + u potential (corresponding mainly to the vibrational levels from v g = 43 up to 49). The pulse produces a rich vibrational dynamics, implying transfer of population between the electronic states, inversion of population, and beats with various Rabi periods T R ve,vg [70] between the populated vibrational levels of the excited and ground states. These phenomena are visible in Fig.…”

Entanglement between electronic and vibrational degrees of freedom in a laser-driven molecular system

“…1). The time-dependent Schrödinger equation associated with the radial motion of the wavepackets Ψ e (R, t) and Ψ g (R, t) in the electronic channels, written using the rotating wave approximation with the frequency ω L /2π [30,31], is:…”

“…. In this case one can write an analytic expression for the population |c ve (t)| 2 , showing the Rabi beats induced by the coupling between the two vibrational states with energies E ve , E vg [31]:…”