Achieving ground-state polar molecular condensates by chainwise atom-molecule adiabatic passage

TL;DR

This paper extends chainwise STIRAP techniques to convert atomic Bose-Einstein condensates into ground-state polar molecular condensates efficiently, reducing laser power requirements by optimizing intermediate laser fields.

Contribution

It introduces a generalized chainwise STIRAP method for atom-molecule systems, highlighting the role of intermediate laser fields and stability analysis to improve efficiency.

Findings

Optimized intermediate laser fields reduce photoassociation laser power.

Enhanced stability analysis improves adiabatic passage efficiency.

Method enables direct conversion of atomic BECs to molecular BECs.

Abstract

We generalize the idea of chainwise stimulated Raman adiabatic passage (STIRAP) [Kuznetsova \textit{et al.} Phys. Rev. A \textbf{78}, 021402(R) (2008)] to a photoassociation-based chainwise atom-molecule system, with the goal of directly converting two-species atomic Bose-Einstein condensates (BEC) into a ground polar molecular BEC. We pay particular attention to the intermediate Raman laser fields, a control knob inaccessible to the usual three-level model. We find that an appropriate exploration of both the intermediate laser fields and the stability property of the atom-molecule STIRAP can greatly reduce the power demand on the photoassociation laser, a key concern for STIRAPs starting from free atoms due to the small Franck-Condon factor in the free-bound transition.