Production of Cold Molecules via Magnetically Tunable Feshbach Resonances

Published

October 12, 2021

Author(s)

T Koehler, K Goral, Paul S. Julienne

Abstract

Magnetically tunable Feshbach resonances were employed to associate cold diatomic molecules in a series of experiments involving both atomic Bose as well as two spin component Fermi gases. This review illustrates theoretical concepts of both the particular nature of the highly excited Feshbach molecules produced and the techniques for their association from unbound atom pairs. Coupled channels theory provides the rigorous formulation of the microscopic physics of Feshbach resonances in cold gases. Concepts of dressed versus bare energy states, universal properties of Feshbach molecules, as well as the classification in terms of entrance- and closed-channel dominated resonances are introduced on the basis of practical two-channel approaches. Their significance is illustrated for several experimental observations, such as binding energies and lifetimes with respect to collisional relaxation. Molecular association and dissociation are discussed in the context of techniques involving linear magnetic eld sweeps in cold Bose and Fermi gases as well as pulse sequences leading to Ramsey-type interference fringes. Their descriptions in terms of Landau-Zener, two-level mean eld as well as beyond mean field approaches are reviewed in detail, including the associated ranges of validity.

Citation

Reviews of Modern Physics

Pub Type

Journals

Keywords

Bose-Einstein condensation, cold molecules, Feshbach resonances, ultracold atoms

Citation

Koehler, T. , Goral, K. and Julienne, P. (2021), Production of Cold Molecules via Magnetically Tunable Feshbach Resonances, Reviews of Modern Physics (Accessed May 10, 2025)