This thesis presents the investigation of the two-body scattering properties of cold atoms in \nsodium and lithium-sodium mixtures and their effects on the many body dynamics. Since both \nspecies are alkali atoms, the combined spin of both unpaired electrons can be either zero or one, \nproviding two different scattering channels. \nThe coupling of bound molecular states in these channels with the free atoms asymptote \ngives rise to the rich field of Feshbach resonance physics, where the interaction between the \nparticles can be controlled as an easily accessible experimental parameter. We have investigated \nthe Feshbach spectrum in the bosonic 7LiNa mixture and could confirm predictions based on \n6LiNa measurements, with a shift of the predicted spectrum by about 50 G. Also, the prospects \nof interaction tuning via Feshbach resonances were examined. \nThe difference of the scattering lengths of the electronic potentials also causes a coupling \nof atomic collisional channels, which can enable a spin exchange between the atoms. In this \nthesis, spin exchange processes have been studied in coherent oscillations in a thermal gas and \na Bose-Einstein condensate of sodium, as well as the evolution of this spinor gas into its ground \nstate. Preliminary studies of the heteronuclear spin exchange process in both the bosonic 7LiNa \nand in the fermionic-bosonic mixture 6LiNa are presented as well.This thesis presents the investigation of the two-body scattering properties of cold atoms in \nsodium and lithium-sodium mixtures and their effects on the many body dynamics. Since both \nspecies are alkali atoms, the combined spin of both unpaired electrons can be either zero or one, \nproviding two different scattering channels. \nThe coupling of bound molecular states in these channels with the free atoms asymptote \ngives rise to the rich field of Feshbach resonance physics, where the interaction between the \nparticles can be controlled as an easily accessible experimental parameter. We have investigated \nthe Feshbach spectrum in the bosonic 7LiNa mixture and could confirm predictions based on \n6LiNa measurements, with a shift of the predicted spectrum by about 50 G. Also, the prospects \nof interaction tuning via Feshbach resonances were examined. \nThe difference of the scattering lengths of the electronic potentials also causes a coupling \nof atomic collisional channels, which can enable a spin exchange between the atoms. In this \nthesis, spin exchange processes have been studied in coherent oscillations in a thermal gas and \na Bose-Einstein condensate of sodium, as well as the evolution of this spinor gas into its ground \nstate. Preliminary studies of the heteronuclear spin exchange process in both the bosonic 7LiNa \nand in the fermionic-bosonic mixture 6LiNa are presented as well.

Jan 1, 20160 citations

Observation of a Feshbach resonance in a Fermi gas of atoms

Cindy A. Regal, Thomas H. Loftus, Michelle Lynne Olsen +1 more

APSMay 1, 20020 citations

Dynamics of Feshbach molecules in an ultracold three-component mixture

Alexander Y. Khramov, Anders H. Hansen, Alan O. Jamison +2 more

We present investigations of the formation rate and collisional stability of lithium Feshbach molecules in an ultracold three-component mixture composed of two resonantly interacting fermionic ${}^{6}$ Li spin states and bosonic ${}^{174}$ Yb. We observe long molecule lifetimes ( $>100$ ms) even in the presence of a large ytterbium bath and extract reaction rate coefficients of the system. We find good collisional stability of the mixture in the unitary regime, opening new possibilities for studies and probes of strongly interacting quantum gases in contact with a bath species.We present investigations of the formation rate and collisional stability of lithium Feshbach molecules in an ultracold three-component mixture composed of two resonantly interacting fermionic ${}^{6}$Li spin states and bosonic ${}^{174}$Yb. We observe long molecule lifetimes ($>100$ ms) even in the presence of a large ytterbium bath and extract reaction rate coefficients of the system. We find good collisional stability of the mixture in the unitary regime, opening new possibilities for studies and probes of strongly interacting quantum gases in contact with a bath species.

arXiv:1207.2187Physical Review ASep 10, 201216 citations

Observation of Feshbach resonances in the collisions of ultracold lithium-6 and cesium-133 atoms

Shih-Kuang Tung, Jacob Johansen, Karina Jiménez-García +2 more

Bulletin of the American Physical SocietyJun 4, 20130 citations

We present investigations of the formation rate and collisional stability of lithium Feshbach molecules in an ultracold three-component mixture composed of two resonantly interacting fermionic

{}^{6}

Li spin states and bosonic

{}^{174}

Yb. We observe long molecule lifetimes (

>100

ms) even in the presence of a large ytterbium bath and extract reaction rate coefficients of the system. We find good collisional stability of the mixture in the unitary regime, opening new possibilities for studies and probes of strongly interacting quantum gases in contact with a bath species.