Metastable helium is buffer gas cooled, magnetically trapped, and evaporatively cooled in large numbers. ${10}^{11}$ $^{4}\mathrm{He}^{*}$ atoms are trapped at an initial temperature of $400\phantom{\rule{0.3em}{0ex}}\mathrm{mK}$ and evaporatively cooled into the ultracold regime, resulting in a cloud of $2\ifmmode\pm\else\textpm\fi{}0.5\ifmmode\times\else\texttimes\fi{}{10}^{9}$ atoms at $1.4\ifmmode\pm\else\textpm\fi{}0.2\phantom{\rule{0.3em}{0ex}}\mathrm{mK}$. Efficient evaporation indicates low collisional loss for $^{4}\mathrm{He}^{*}$ in both the ultracold and multi-partial-wave regime, in agreement with theory.Metastable helium is buffer gas cooled, magnetically trapped, and evaporatively cooled in large numbers. ${10}^{11}$ $^{4}\mathrm{He}^{*}$ atoms are trapped at an initial temperature of $400\phantom{\rule{0.3em}{0ex}}\mathrm{mK}$ and evaporatively cooled into the ultracold regime, resulting in a cloud of $2\ifmmode\pm\else\textpm\fi{}0.5\ifmmode\times\else\texttimes\fi{}{10}^{9}$ atoms at $1.4\ifmmode\pm\else\textpm\fi{}0.2\phantom{\rule{0.3em}{0ex}}\mathrm{mK}$. Efficient evaporation indicates low collisional loss for $^{4}\mathrm{He}^{*}$ in both the ultracold and multi-partial-wave regime, in agreement with theory.

Physical Review ADec 29, 200512 citations

Production of a Bose Einstein condensate of metastable helium atoms

Franck Pereira dos Santos, Jérémie Léonard, Junmin Wang +6 more

Frontiers of Science: In Celebration of the 80th Birthday of C N YangSep 1, 20030 citations

Giant Helium Dimers Produced by Photoassociation of Ultracold Metastable Atoms

Jérémie Léonard, M. Walhout, Allard P. Mosk +3 more

We produce giant, purely long-range helium dimers by photoassociation of metastable helium atoms in a magnetically trapped, ultracold cloud. The photoassociation laser is detuned close to the atomic 2(3)S1-2(3)P0 line and produces strong heating of the sample when resonant with molecular bound states. The temperature of the cloud serves as an indicator of the molecular spectrum. We report good agreement between our spectroscopic measurements and our calculations of the five bound states belonging to a 0(+)(u) purely long-range potential well. These previously unobserved states have classical inner turning points of about 150a(0) and outer turning points as large as 1150a(0).We produce giant, purely long-range helium dimers by photoassociation of metastable helium atoms in a magnetically trapped, ultracold cloud. The photoassociation laser is detuned close to the atomic 2(3)S1-2(3)P0 line and produces strong heating of the sample when resonant with molecular bound states. The temperature of the cloud serves as an indicator of the molecular spectrum. We report good agreement between our spectroscopic measurements and our calculations of the five bound states belonging to a 0(+)(u) purely long-range potential well. These previously unobserved states have classical inner turning points of about 150a(0) and outer turning points as large as 1150a(0).

arXiv:cond-mat/0304446Physical Review LettersAug 15, 200367 citations

Metastable helium is buffer gas cooled, magnetically trapped, and evaporatively cooled in large numbers.

{10}^{11}

^{4}\mathrm{He}^{*}

atoms are trapped at an initial temperature of

400\phantom{\rule{0.3em}{0ex}}\mathrm{mK}

and evaporatively cooled into the ultracold regime, resulting in a cloud of $2\ifmmode\pm\else\textpm\fi{}0.5\ifmmode\times\else\texttimes\fi{}{10}^{9}$ atoms at $1.4\ifmmode\pm\else\textpm\fi{}0.2\phantom{\rule{0.3em}{0ex}}\mathrm{mK}$. Efficient evaporation indicates low collisional loss for

^{4}\mathrm{He}^{*}

in both the ultracold and multi-partial-wave regime, in agreement with theory.