Production of bosonic molecules in the nonequilibrium dynamics of a degenerate Fermi gas across a Feshbach resonance
| dc.contributor | Pokrovsky, Valery L. | |
| dc.creator | Dobrescu, Bogdan E. | |
| dc.date.accessioned | 2010-01-15T00:16:30Z | |
| dc.date.accessioned | 2010-01-16T02:15:24Z | |
| dc.date.accessioned | 2017-04-07T19:56:47Z | |
| dc.date.available | 2010-01-15T00:16:30Z | |
| dc.date.available | 2010-01-16T02:15:24Z | |
| dc.date.available | 2017-04-07T19:56:47Z | |
| dc.date.created | 2006-08 | |
| dc.date.issued | 2009-06-02 | |
| dc.description.abstract | In this thesis I present a nonequilibrium quantum field theory that describes the production of molecular dimers from a two-component quantum-degenerate atomic Fermi gas, via a linear downward sweep of a magnetic field across an s-wave Feshbach resonance. This problem raises interest because it is presently unclear as to why deviations from the universal Landau-Zener formula for the transition probability at two-level crossing are observed in the experimentally measured production efficiencies. The approach is based on evaluating real-time Green functions within the Keldysh- Schwinger formalism. The effects of quantum statistics associated with Pauli blocking for fermions and induced emission for bosons, characteristic of particle scattering in a quantum-degenerate many-body medium, are fully accounted for. I show that the molecular conversion efficiency is represented by a power series in terms of a dimensionless parameter which, in the zero-temperature limit, depends solely on the initial gas density and the Landau-Zener parameter. This result reveals a hindrance of the canonical Landau-Zener transition probability due to many-body effects, and presents an explanation for the experimentally observed deviations. A second topic treated in this thesis concerns the study of non-adiabatic transitions in N-state Landau-Zener systems. In connection to this, I provide a proof of the conjecture put forth by Brundobler and Elser, regarding the survival probability on the diabatic levels with maximum/minimum slope. | |
| dc.identifier.uri | http://hdl.handle.net/1969.1/ETD-TAMU-1838 | |
| dc.language.iso | en_US | |
| dc.subject | Feshbach resonance | |
| dc.subject | Keldysh GF | |
| dc.subject | nonequilibrium QFT | |
| dc.title | Production of bosonic molecules in the nonequilibrium dynamics of a degenerate Fermi gas across a Feshbach resonance | |
| dc.type | Book | |
| dc.type | Thesis |