Boson-fermion coherence in a spherically symmetric harmonic trap
- Optical Sciences Center, The University of Arizona, Tucson, Arizona 85721 (United States)
We consider the photoassociation of a low-density gas of quantum-degenerate trapped fermionic atoms into bosonic molecules in a spherically symmetric harmonic potential. For a dilute system and the photoassociation coupling energy small compared to the level separation of the trap, only those fermions in the single shell with Fermi energy are coupled to the bosonic molecular field. Introducing a collective pseudospin operator formalism we show that this system can then be mapped onto the Tavis-Cummings Hamiltonian of quantum optics, with an additional pairing interaction. By exact diagonalization of the Hamiltonian, we examine the ground state and low excitations of the Bose-Fermi system, and study the dynamics of the coherent coupling between atoms and molecules. In a semiclassical description of the system, the pairing interaction between fermions is shown to result in a self-trapping transition in the photoassociation, with a sudden suppression of the coherent oscillations between atoms and molecules. We also show that the full quantum dynamics of the system is dominated by quantum fluctuations in the vicinity of the self-trapping solution.
- OSTI ID:
- 20650475
- Journal Information:
- Physical Review. A, Vol. 71, Issue 3; Other Information: DOI: 10.1103/PhysRevA.71.033624; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ATOM-MOLECULE COLLISIONS
ATOMS
BOSONS
COUPLING
DENSITY
EXCITATION
EXCITED STATES
FERMIONS
FLUCTUATIONS
GROUND STATES
HAMILTONIANS
HARMONIC POTENTIAL
MATHEMATICAL SOLUTIONS
MOLECULES
OPTICS
PAIRING INTERACTIONS
QUANTUM MECHANICS
SEMICLASSICAL APPROXIMATION
TRAPPING
TRAPS