https://doi.org/10.1140/epjd/e2004-00122-3
New directions in degenerate dipolar molecules via collective association
1
QUANTOP–Danish National Research Foundation
Center for Quantum Optics, Department of Physics and Astronomy,
University of Aarhus, 8000 Aarhus C, Denmark
2
Helsinki Institute of Physics, PL 64, 00014
Helsingin yliopisto, Finland
3
School of Pure and Applied Physics,
University of KwaZulu-Natal, Durban 4041, South Africa
4
Department of Physics, University of Turku, 20014
Turun yliopisto, Finland
5
Department of Physics, University of Connecticut,
Storrs, Connecticut, 06269-3046, USA
Corresponding author: a mattmackie2000@yahoo.com
Received:
16
June
2004
Published online:
21
September
2004
We survey results on the creation of heteronuclear Fermi molecules by tuning a degenerate Bose-Fermi mixture into the neighborhood of an association resonance, either photoassociation or Feshbach, as well as the subsequent prospects for Cooper-like pairing between atoms and molecules. In the simplest case of only one molecular state, corresponding to either a Feshbach resonance or one-color photoassociation, the system displays Rabi oscillations and rapid adiabatic passage between a Bose-Fermi mixture of atoms and fermionic molecules. For two-color photoassociation, the system admits stimulated Raman adiabatic passage (STIRAP) from a Bose-Fermi mixture of atoms to stable Fermi molecules, even in the presence of particle-particle interactions. By tailoring the STIRAP sequence it is possible to deliberately convert only a fraction of the initial atoms, leaving a finite fraction of bosons behind to induce atom-molecule Cooper pairing via density fluctuations; unfortunately, this enhancement is insufficient to achieve a superfluid transition with present ultracold technology. We therefore propose the use of an association resonance that converts atoms and diatomic molecules (dimers) into triatomic molecules (trimers), which leads to a crossover from a Bose-Einstein condensate of trimers to atom-dimer Cooper pairs. Because heteronuclear dimers may possess a permanent electric dipole moment, this overall system presents an opportunity to investigate novel microscopic physics.
PACS: 03.75.Ss – Degenerate Fermi gases / 05.30.Fk – Fermion systems and electron gas / 34.10.+x – General theories and models of atomic and molecular collisions and interactions (including statistical theories, transition state, stochastic and trajectory models, etc.) / 74.20.Mn – Nonconventional mechanisms (spin fluctuations, polarons and bipolarons, resonating valence bond model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.) / 21.10.-k – Properties of nuclei; nuclear energy levels
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004
