We report on the preparation of a quantum degenerate mixture of $^{23}\mathrm{Na}\phantom{\rule{0.16em}{0ex}}^{40}\mathrm{K}$ molecules and $^{40}\mathrm{K}$ atoms. A deeply degenerate atomic mixture of $^{23}\mathrm{Na}$ and $^{40}\mathrm{K}$ atoms with a large number ratio (${N}_{F}/{N}_{B}\ensuremath{\approx}6$) is prepared in a large-volume optical dipole trap. About $3.0\ifmmode\times\else\texttimes\fi{}{10}^{4}\phantom{\rule{0.16em}{0ex}}^{23}\mathrm{Na}\phantom{\rule{0.16em}{0ex}}^{40}\mathrm{K}$ ground-state molecules are created through magnetoassociation followed by stimulated Raman adiabatic passage. The pure molecular gas is in the moderately degenerate regime. In the atom-molecule mixture, the elastic collisions provide a thermalization mechanism for the molecules. The calculated thermalization time constant is smaller than the lifetime of the molecules in the atom-molecule mixture. This indicates that the molecules may reach thermal equilibrium due to elastic atom-molecule collisions before notable losses take place. In a few tens of milliseconds, the degeneracy of the molecules is maintained. This time interval is long enough for the study of strongly interacting atom-molecule mixtures and the production of ultracold triatomic molecular gases.We report on the preparation of a quantum degenerate mixture of $^{23}\mathrm{Na}\phantom{\rule{0.16em}{0ex}}^{40}\mathrm{K}$ molecules and $^{40}\mathrm{K}$ atoms. A deeply degenerate atomic mixture of $^{23}\mathrm{Na}$ and $^{40}\mathrm{K}$ atoms with a large number ratio (${N}_{F}/{N}_{B}\ensuremath{\approx}6$) is prepared in a large-volume optical dipole trap. About $3.0\ifmmode\times\else\texttimes\fi{}{10}^{4}\phantom{\rule{0.16em}{0ex}}^{23}\mathrm{Na}\phantom{\rule{0.16em}{0ex}}^{40}\mathrm{K}$ ground-state molecules are created through magnetoassociation followed by stimulated Raman adiabatic passage. The pure molecular gas is in the moderately degenerate regime. In the atom-molecule mixture, the elastic collisions provide a thermalization mechanism for the molecules. The calculated thermalization time constant is smaller than the lifetime of the molecules in the atom-molecule mixture. This indicates that the molecules may reach thermal equilibrium due to elastic atom-molecule collisions before notable losses take place. In a few tens of milliseconds, the degeneracy of the molecules is maintained. This time interval is long enough for the study of strongly interacting atom-molecule mixtures and the production of ultracold triatomic molecular gases.

arXiv:2208.09620Physical Review AJan 17, 202315 citations

Atoms in Molecules

Nikos Georgopoulos, Jerome K. Percus

Springer eBooksJan 1, 19931 citation

Collisional decay of Rb87 Feshbach molecules at 1005.8G

Niels Syassen, Thomas Volz, S. Teichmann +2 more

We present measurements of the loss-rate coefficients ${K}_{\mathit{am}}$ and ${K}_{\mathit{mm}}$ caused by inelastic atom-molecule and molecule-molecule collisions. A thermal cloud of atomic $^{87}\mathrm{Rb}$ is prepared in an optical dipole trap. A magnetic field is ramped across the Feshbach resonance at $1007.4\phantom{\rule{0.3em}{0ex}}\mathrm{G}$ . This associates atom pairs to molecules. A measurement of the molecule loss at $1005.8\phantom{\rule{0.3em}{0ex}}\mathrm{G}$ yields ${K}_{\mathit{am}}=2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{3}∕\mathrm{s}$. Additionally, the atoms can be removed with blast light. In this case, the measured molecule loss yields ${K}_{\mathit{mm}}=3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{3}∕\mathrm{s}$.We present measurements of the loss-rate coefficients ${K}_{\mathit{am}}$ and ${K}_{\mathit{mm}}$ caused by inelastic atom-molecule and molecule-molecule collisions. A thermal cloud of atomic $^{87}\mathrm{Rb}$ is prepared in an optical dipole trap. A magnetic field is ramped across the Feshbach resonance at $1007.4\phantom{\rule{0.3em}{0ex}}\mathrm{G}$. This associates atom pairs to molecules. A measurement of the molecule loss at $1005.8\phantom{\rule{0.3em}{0ex}}\mathrm{G}$ yields ${K}_{\mathit{am}}=2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{3}∕\mathrm{s}$. Additionally, the atoms can be removed with blast light. In this case, the measured molecule loss yields ${K}_{\mathit{mm}}=3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{3}∕\mathrm{s}$.

arXiv:cond-mat/0611047Physical Review ADec 13, 200631 citations

Molecules Without Atoms

Anthony Ruth, Laura C. Collins, Kenjiro K. Gomes +1 more

Bulletin of the American Physical SocietyMar 15, 20170 citations

Gaseous atoms or molecules: what happens at ultra-low temperature?

Masatoshi Kajita

As an introduction, the states of atoms and molecules are introduced. At room temperature, gaseous atoms and molecules move very fast. We imagine that the gaseous phase is transformed to liquid or solid phase by cooling, but it is possible only with high density of atoms and molecules. With low densities, atoms and molecules also stay in the gaseous state at low temperature. Research using cold atoms and molecules, trapped by electric or magnetic field, give important information to develop new physics.As an introduction, the states of atoms and molecules are introduced. At room temperature, gaseous atoms and molecules move very fast. We imagine that the gaseous phase is transformed to liquid or solid phase by cooling, but it is possible only with high density of atoms and molecules. With low densities, atoms and molecules also stay in the gaseous state at low temperature. Research using cold atoms and molecules, trapped by electric or magnetic field, give important information to develop new physics.

Institute of Physics eBooksJun 1, 20200 citations

Atoms and Energy

Pieter Kok

Undergraduate lecture notes in physicsJan 1, 20230 citations

We report on the preparation of a quantum degenerate mixture of

^{23}\mathrm{Na}\phantom{\rule{0.16em}{0ex}}^{40}\mathrm{K}

molecules and

^{40}\mathrm{K}

atoms. A deeply degenerate atomic mixture of

^{23}\mathrm{Na}

and

^{40}\mathrm{K}

atoms with a large number ratio (${N}_{F}/{N}_{B}\ensuremath{\approx}6$) is prepared in a large-volume optical dipole trap. About $3.0\ifmmode\times\else\texttimes\fi{}{10}^{4}\phantom{\rule{0.16em}{0ex}}^{23}\mathrm{Na}\phantom{\rule{0.16em}{0ex}}^{40}\mathrm{K}$ ground-state molecules are created through magnetoassociation followed by stimulated Raman adiabatic passage. The pure molecular gas is in the moderately degenerate regime. In the atom-molecule mixture, the elastic collisions provide a thermalization mechanism for the molecules. The calculated thermalization time constant is smaller than the lifetime of the molecules in the atom-molecule mixture. This indicates that the molecules may reach thermal equilibrium due to elastic atom-molecule collisions before notable losses take place. In a few tens of milliseconds, the degeneracy of the molecules is maintained. This time interval is long enough for the study of strongly interacting atom-molecule mixtures and the production of ultracold triatomic molecular gases.

We present measurements of the loss-rate coefficients

{K}_{\mathit{am}}

and

{K}_{\mathit{mm}}

caused by inelastic atom-molecule and molecule-molecule collisions. A thermal cloud of atomic

^{87}\mathrm{Rb}

is prepared in an optical dipole trap. A magnetic field is ramped across the Feshbach resonance at

1007.4\phantom{\rule{0.3em}{0ex}}\mathrm{G}

. This associates atom pairs to molecules. A measurement of the molecule loss at

1005.8\phantom{\rule{0.3em}{0ex}}\mathrm{G}

yields ${K}_{\mathit{am}}=2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{3}∕\mathrm{s}$. Additionally, the atoms can be removed with blast light. In this case, the measured molecule loss yields ${K}_{\mathit{mm}}=3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{3}∕\mathrm{s}$.