Title :
Resonance superfluidity in a lithium gas: renormalization of resonance scattering theory
Author :
Kokkelmans, S.J.J.M.F. ; Milstein, J.N. ; Walser, R. ; Holland, M.J. ; Chiofalo, M.L.
Author_Institution :
Joint Inst. for Lab. Astrophys., Colorado Univ., Boulder, CO, USA
Abstract :
Summary form only given. For non-resonant atomic interactions the properties of ultra-cold scattering can be accurately represented by the scattering length. When the interactions are resonant, for instance when the atoms are colliding via a Feshbach resonance, the scattering properties become strongly dependent on energy, and the scattering length approximation is no longer valid. We show that there is a limited set of parameters that fully characterizes the scattering in the ultra-cold regime, and that this description can be easily incorporated into a theory of many-body physics. In effect, it can be shown that with a Hamiltonian where the resonant bound-state is explicitly treated, the resulting many-body mean-field equations have built in the microscopic two-body coupled-channels scattering equations. We have used this many-body theory to derive a theory of resonance superfluidity, and applied it to both fermionic /sup 40/K and /sup 6/Li. Since the scattering length a does not appear as an expansion parameter of the theory it can be shown that this field theory does not break down as a goes to infinity. In fact, the theory describes the high-T/sub c/ behavior of the system and predicts a critical temperature which can be as high as half the Fermi temperature.
Keywords :
bound states; fermion systems; lithium; many-body problems; potassium; renormalisation; resonant states; superfluidity; /sup 40/K; /sup 6/Li; /sup 6/Li gas; Fermi temperature; Feshbach resonance; Hamiltonian; critical temperature; fermionic /sup 40/K; high-T/sub c/ behavior; many-body mean-field equations; many-body physics; microscopic two-body coupled-channels scattering equations; nonresonant atomic interactions; resonance scattering theory renormalization; resonance superfluidity; resonant bound-state; scattering length approximation; ultra-cold scattering; Lithium; Potassium;
Conference_Titel :
Quantum Electronics and Laser Science Conference, 2002. QELS '02. Technical Digest. Summaries of Papers Presented at the
Conference_Location :
Long Beach, CA, USA
Print_ISBN :
1-55752-708-3
DOI :
10.1109/QELS.2002.1031265