Closed shell ions like Na+, as well as many molecular ions, cannot be easily laser cooled, for spectroscopy, quantum gates, and near zero-K reaction studies. We report on experiments studying collisions between trapped ions and trapped cold atoms. The ion-atom interaction is dominated by long-range polarization forces, principally a term V $\sim -\alpha $ /R $^{4}$ , $\alpha $ being the dipole polarizability of the neutral. The Hybrid trap consists of a linear Paul ion trap, set to trap Na+ ions, centered on a sodium magneto-optical trap (MOT). We investigate the sympathetic cooling of the (equal atomic mass) Na+ ion cloud concentric with the MOT, using either the 3s F=2$\to $3p F$ ^{\prime} $=3 or the 3s F=2$ \to $3p F$ ^{\prime}$= 2 MOT transitions. The lifetime of the ions in the Paul trap is observed to be detectably longer when they are sympathetically cooled by the cold neutral MOT atoms, consistent with simulations via SIMION.Closed shell ions like Na+, as well as many molecular ions, cannot be easily laser cooled, for spectroscopy, quantum gates, and near zero-K reaction studies. We report on experiments studying collisions between trapped ions and trapped cold atoms. The ion-atom interaction is dominated by long-range polarization forces, principally a term V $\sim -\alpha $ /R$^{4}$, $\alpha $ being the dipole polarizability of the neutral. The Hybrid trap consists of a linear Paul ion trap, set to trap Na+ ions, centered on a sodium magneto-optical trap (MOT). We investigate the sympathetic cooling of the (equal atomic mass) Na+ ion cloud concentric with the MOT, using either the 3s F=2$\to $3p F$^{\prime}$=3 or the 3s F=2$\to $3p F$^{\prime}$= 2 MOT transitions. The lifetime of the ions in the Paul trap is observed to be detectably longer when they are sympathetically cooled by the cold neutral MOT atoms, consistent with simulations via SIMION.

Nov 18, 20110 citations

Single trapped ions sympathetically cooled by ultracold atoms

Arne Haerter, Andreas Brunner, Artjom Krükow +3 more

Bulletin of the American Physical SocietyJun 8, 20120 citations

Evidence of sympathetic cooling of Na + ions by a Na magneto-optical trap in a hybrid trap

I. Sivarajah, D. S. Goodman, James E. Wells +2 more

A hybrid ion-neutral trap provides an ideal system to study collisional dynamics between ions and neutral atoms. This system provides a general cooling method that can be applied to species that do not have optically accessible transitions and can also potentially cool internal degrees of freedom. The long-range polarization potentials ($V\ensuremath{\propto}\ensuremath{-}\ensuremath{\alpha}/{r}^{4}$) between ions and neutrals result in large scattering cross sections at cold temperatures, making the hybrid trap a favorable system for efficient sympathetic cooling of ions by collisions with neutral atoms. We present experimental evidence of sympathetic cooling of trapped Na ${}^{+}$ ions, which are closed shell and therefore do not have a laser-induced atomic transition from the ground state, by equal-mass cold Na atoms in a magneto-optical trap.A hybrid ion-neutral trap provides an ideal system to study collisional dynamics between ions and neutral atoms. This system provides a general cooling method that can be applied to species that do not have optically accessible transitions and can also potentially cool internal degrees of freedom. The long-range polarization potentials ($V\ensuremath{\propto}\ensuremath{-}\ensuremath{\alpha}/{r}^{4}$) between ions and neutrals result in large scattering cross sections at cold temperatures, making the hybrid trap a favorable system for efficient sympathetic cooling of ions by collisions with neutral atoms. We present experimental evidence of sympathetic cooling of trapped Na${}^{+}$ ions, which are closed shell and therefore do not have a laser-induced atomic transition from the ground state, by equal-mass cold Na atoms in a magneto-optical trap.

arXiv:1209.2106Physical Review ADec 26, 201259 citations

Scattering and Sympathetic Cooling within an Ion-Neutral Hybrid Trap

Douglas S. Goodman

Dilute ion-neutral gas mixtures are an interesting system to study due to the rich variety and enormous strength of their scattering interactions, especially in the cold and ultracold regimes. Ion-neutral collisions are dominated by long-range polarization potentials that lead to cross sections several orders of magnitude larger than typical neutral-neutral van der Waals interactions. These large ion-neutral interactions can play an important role in atomic and molecular optical physics, astrophysics, and quantum chemistry. Thanks to advances in theoretical modeling of ion-neutral scattering and the development of new ion-neutral hybrid trapping and cooling technology, interest in this previously unexplored area of cold atomic and molecular physics has surged over the past decade.\nThe ion-neutral hybrid trap, composed of a magneto-optical trap concentric within a linear Paul trap, offers the ideal playground for studying and manipulating ion-neutral interactions over a wide energy range (~ 1 μK - 104 K). This dissertation discusses the development of UConn's hybrid trap, compares experimental measurements of the Na+ - Na system and Ca+ - Na system's low-energy collision rates with previously reported theory, and reports on experimental and simulation results of the sympathetic cooling of Na+ ions by laser cooled Na atoms.Dilute ion-neutral gas mixtures are an interesting system to study due to the rich variety and enormous strength of their scattering interactions, especially in the cold and ultracold regimes. Ion-neutral collisions are dominated by long-range polarization potentials that lead to cross sections several orders of magnitude larger than typical neutral-neutral van der Waals interactions. These large ion-neutral interactions can play an important role in atomic and molecular optical physics, astrophysics, and quantum chemistry. Thanks to advances in theoretical modeling of ion-neutral scattering and the development of new ion-neutral hybrid trapping and cooling technology, interest in this previously unexplored area of cold atomic and molecular physics has surged over the past decade.\nThe ion-neutral hybrid trap, composed of a magneto-optical trap concentric within a linear Paul trap, offers the ideal playground for studying and manipulating ion-neutral interactions over a wide energy range (~ 1 μK - 104 K). This dissertation discusses the development of UConn's hybrid trap, compares experimental measurements of the Na+ - Na system and Ca+ - Na system's low-energy collision rates with previously reported theory, and reports on experimental and simulation results of the sympathetic cooling of Na+ ions by laser cooled Na atoms.

Jan 1, 20150 citations

^{4}

, $\alpha $ being the dipole polarizability of the neutral. The Hybrid trap consists of a linear Paul ion trap, set to trap Na+ ions, centered on a sodium magneto-optical trap (MOT). We investigate the sympathetic cooling of the (equal atomic mass) Na+ ion cloud concentric with the MOT, using either the 3s F=2$\to

3p F

^{\prime}

=3 or the 3s F=2

\to

3p F

^{\prime}$= 2 MOT transitions. The lifetime of the ions in the Paul trap is observed to be detectably longer when they are sympathetically cooled by the cold neutral MOT atoms, consistent with simulations via SIMION.

{}^{+}

ions, which are closed shell and therefore do not have a laser-induced atomic transition from the ground state, by equal-mass cold Na atoms in a magneto-optical trap.