We present the production of dual-species Bose-Einstein condensates (BECs) of $^{39}\mathrm{K}$ and $^{87}\mathrm{Rb}$ . Preparation of both species in the $\left|F=1,{m}_{F}=\ensuremath{-}1\right\ensuremath{\rangle}$ state enabled us to exploit a total of three Feshbach resonances, which allows for simultaneous Feshbach tuning of the $^{39}\mathrm{K}$ intraspecies and the $^{39}\mathrm{K}\text{\ensuremath{-}}^{87}\mathrm{Rb}$ interspecies scattering length. Thus dual-species Bose-Einstein condensates were produced by sympathetic cooling of $^{39}\mathrm{K}$ with $^{87}\mathrm{Rb}$ . A dark spontaneous force optical trap was used for $^{87}\mathrm{Rb}$ to reduce the losses in $^{39}\mathrm{K}$ due to light-assisted collisions in the optical trapping phase, which can be of benefit for other dual-species experiments. The tunability of the scattering length was used to perform precision spectroscopy of the interspecies Feshbach resonance located at 117.56(2) G and to determine the width of the resonance to 1.21(5) G by rethermalization measurements. The transition region from miscible to immiscible dual-species condensates was investigated and the interspecies background scattering length was determined to $28.5{a}_{0}$ using an empirical model. This paves the way for dual-species experiments with $^{39}\mathrm{K}$ and $^{87}\mathrm{Rb}$ BECs ranging from molecular physics to precision metrology.We present the production of dual-species Bose-Einstein condensates (BECs) of $^{39}\mathrm{K}$ and $^{87}\mathrm{Rb}$. Preparation of both species in the $\left|F=1,{m}_{F}=\ensuremath{-}1\right\ensuremath{\rangle}$ state enabled us to exploit a total of three Feshbach resonances, which allows for simultaneous Feshbach tuning of the $^{39}\mathrm{K}$ intraspecies and the $^{39}\mathrm{K}\text{\ensuremath{-}}^{87}\mathrm{Rb}$ interspecies scattering length. Thus dual-species Bose-Einstein condensates were produced by sympathetic cooling of $^{39}\mathrm{K}$ with $^{87}\mathrm{Rb}$. A dark spontaneous force optical trap was used for $^{87}\mathrm{Rb}$ to reduce the losses in $^{39}\mathrm{K}$ due to light-assisted collisions in the optical trapping phase, which can be of benefit for other dual-species experiments. The tunability of the scattering length was used to perform precision spectroscopy of the interspecies Feshbach resonance located at 117.56(2) G and to determine the width of the resonance to 1.21(5) G by rethermalization measurements. The transition region from miscible to immiscible dual-species condensates was investigated and the interspecies background scattering length was determined to $28.5{a}_{0}$ using an empirical model. This paves the way for dual-species experiments with $^{39}\mathrm{K}$ and $^{87}\mathrm{Rb}$ BECs ranging from molecular physics to precision metrology.

arXiv:1505.07975Physical Review ANov 4, 2015102 citations

Low-dimensional BEC

Francisco J. Sevilla, M. Grether, Mauricio Fortes +4 more

arXiv:cond-mat/0006458Journal of Low Temperature PhysicsDec 1, 20009 citations

Dual-species Bose-Einstein condensates of Li7 and Cs133

Y.-D. Chen, W.-X. Li, Y.-T. Sun +3 more

We report the creation of dual-species Bose-Einstein condensates (BECs) of $^{7}\mathrm{Li}$ and $^{133}\mathrm{Cs}$ . These BECs are formed in a bichromatic optical dipole trap created with 1550- and 780-nm laser beams. During the production process, an external magnetic field of 886 G is applied to adjust the scattering lengths to ${a}_{\mathrm{Cs}}=123{a}_{0}, {a}_{\mathrm{Li}}=484{a}_{0}$ , and ${a}_{\mathrm{LiCs}}=248{a}_{0}$ . These scattering lengths allow for efficient evaporation and sympathetic cooling. The dual-species BECs are typically produced with $1.5\ifmmode\times\else\texttimes\fi{}{10}^{4}$ Cs atoms and $6.0\ifmmode\times\else\texttimes\fi{}{10}^{3}$ Li atoms. This quantum degenerate mixture of Li and Cs provides an ideal platform for exploring phenomena such as polarons and Efimov trimers, as well as for creating ground-state LiCs molecules.We report the creation of dual-species Bose-Einstein condensates (BECs) of $^{7}\mathrm{Li}$ and $^{133}\mathrm{Cs}$. These BECs are formed in a bichromatic optical dipole trap created with 1550- and 780-nm laser beams. During the production process, an external magnetic field of 886 G is applied to adjust the scattering lengths to ${a}_{\mathrm{Cs}}=123{a}_{0}, {a}_{\mathrm{Li}}=484{a}_{0}$, and ${a}_{\mathrm{LiCs}}=248{a}_{0}$. These scattering lengths allow for efficient evaporation and sympathetic cooling. The dual-species BECs are typically produced with $1.5\ifmmode\times\else\texttimes\fi{}{10}^{4}$ Cs atoms and $6.0\ifmmode\times\else\texttimes\fi{}{10}^{3}$ Li atoms. This quantum degenerate mixture of Li and Cs provides an ideal platform for exploring phenomena such as polarons and Efimov trimers, as well as for creating ground-state LiCs molecules.

Physical Review ASep 1, 20235 citations

Universality and novel phases in the BCS-BEC crossover

W. Zwerger

Bulletin of the American Physical SocietyJun 8, 20070 citations

We present the production of dual-species Bose-Einstein condensates (BECs) of

^{39}\mathrm{K}

and

^{87}\mathrm{Rb}

. Preparation of both species in the $\left|F=1,{m}_{F}=\ensuremath{-}1\right\ensuremath{\rangle}$ state enabled us to exploit a total of three Feshbach resonances, which allows for simultaneous Feshbach tuning of the

^{39}\mathrm{K}

intraspecies and the $^{39}\mathrm{K}\text{\ensuremath{-}}^{87}\mathrm{Rb}$ interspecies scattering length. Thus dual-species Bose-Einstein condensates were produced by sympathetic cooling of

^{39}\mathrm{K}

with

^{87}\mathrm{Rb}

. A dark spontaneous force optical trap was used for

^{87}\mathrm{Rb}

to reduce the losses in

^{39}\mathrm{K}

due to light-assisted collisions in the optical trapping phase, which can be of benefit for other dual-species experiments. The tunability of the scattering length was used to perform precision spectroscopy of the interspecies Feshbach resonance located at 117.56(2) G and to determine the width of the resonance to 1.21(5) G by rethermalization measurements. The transition region from miscible to immiscible dual-species condensates was investigated and the interspecies background scattering length was determined to

28.5{a}_{0}

using an empirical model. This paves the way for dual-species experiments with

^{39}\mathrm{K}

and

^{87}\mathrm{Rb}

BECs ranging from molecular physics to precision metrology.

We report the creation of dual-species Bose-Einstein condensates (BECs) of

^{7}\mathrm{Li}

and

^{133}\mathrm{Cs}

. These BECs are formed in a bichromatic optical dipole trap created with 1550- and 780-nm laser beams. During the production process, an external magnetic field of 886 G is applied to adjust the scattering lengths to

{a}_{\mathrm{Cs}}=123{a}_{0}, {a}_{\mathrm{Li}}=484{a}_{0}

, and

{a}_{\mathrm{LiCs}}=248{a}_{0}

. These scattering lengths allow for efficient evaporation and sympathetic cooling. The dual-species BECs are typically produced with $1.5\ifmmode\times\else\texttimes\fi{}{10}^{4}$ Cs atoms and $6.0\ifmmode\times\else\texttimes\fi{}{10}^{3}$ Li atoms. This quantum degenerate mixture of Li and Cs provides an ideal platform for exploring phenomena such as polarons and Efimov trimers, as well as for creating ground-state LiCs molecules.