Two strong nonlinearity regimes in cold molecule formation

TL;DR

This paper identifies two distinct nonlinear regimes in cold molecule formation from atomic Bose-Einstein condensates, characterized by different field detuning and oscillation behaviors, and analyzes their dynamics and efficiency limits.

Contribution

It reveals two strong nonlinearity regimes in molecule formation, provides approximate solutions, and discusses efficiency limits and optimal conditions for different models.

Findings

Association is nearly non-oscillatory at large detuning.

System exhibits Rabi-type oscillations at small detuning.

Strong coupling limits yield at most one-third atomic population conversion.

Abstract

Two distinct strongly non-linear scenarios of molecule formation in an atomic Bose-Einstein condensate (either by photoassociation or Feshbach resonance) corresponding to large and small field detuning are revealed. By examining arbitrary external field configurations, we show that the association process in the first case is almost non-oscillatory in time while in the second case the evolution of the system displays strongly pronounced Rabi-type oscillations. We construct highly accurate approximate solutions for both limit cases. We show that at strong coupling limit the non-crossing models are able to provide conversion of no more than one third of the initial atomic population. Finally, we show that for constant-amplitude models involving a finite final detuning the strong interaction limit is not optimal for molecule formation.