title: Nonlinear adiabatic passage from fermion atoms to boson molecules.
abstract: We study the dynamics of an adiabatic sweep through a Feshbach resonance in a quantum gas of fermionic atoms. Analysis of the dynamical equations, supported by mean-field and many-body numerical results, shows that the dependence of the remaining atomic fraction Gamma on the sweep rate alpha varies from exponential Landau-Zener behavior for a single pair of particles to a power-law dependence for large particle number N. The power law is linear, Gamma is proportional to alpha, when the initial molecular fraction is smaller than the 1/N quantum fluctuations, and Gamma is proportional to alpha(1/3) when it is larger. Experimental data agree well with a linear dependence, but do not conclusively rule out the Landau-Zener model.
authors.affiliation: Department of Chemistry, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 84105, Israel.
authors.forename: E
authors.initials: E
authors.lastname: Pazy
authors.forename: I
authors.initials: I
authors.lastname: Tikhonenkov
authors.forename: Y B
authors.initials: YB
authors.lastname: Band
authors.forename: M
authors.initials: M
authors.lastname: Fleischhauer
authors.forename: A
authors.initials: A
authors.lastname: Vardi