Physical Review Letters

Simultaneous Magneto-Optical Trapping of a Boson-Fermion Mixture of Metastable Helium Atoms

R. J. W. Stas, J. M. McNamara, W. Hogervorst, W. Vassen

Published Jul 27, 2004• 26 citations

Abstract

We simultaneously confine fermionic metastable $^{3}\mathrm{H}\mathrm{e}$ atoms and bosonic metastable $^{4}\mathrm{H}\mathrm{e}$ atoms in a magneto-optical trap. The trapped clouds, containing up to $1.5\ifmmode\times\else\texttimes\fi{}{10}^{8}$ atoms of each isotope, are characterized by measuring ions and metastable helium atoms escaping from the trap. Optical pumping of $^{3}\mathrm{H}\mathrm{e}$ atoms to a nontrapped hyperfine state is investigated and it is shown that large atom numbers can be confined without additional repumping lasers. Unique possibilities for quantum degeneracy experiments with mixtures of spin-polarized metastable $^{3}\mathrm{H}\mathrm{e}$ and $^{4}\mathrm{H}\mathrm{e}$ atoms are indicated.

DOI: 10.1103/physrevlett.93.053001

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Physical Review Letters

Simultaneous Magneto-Optical Trapping of a Boson-Fermion Mixture of Metastable Helium Atoms

R. J. W. Stas, J. M. McNamara, W. Hogervorst, W. Vassen

Published Jul 27, 2004• 26 citations

Publisher

Abstract

We simultaneously confine fermionic metastable

^{3}\mathrm{H}\mathrm{e}

atoms and bosonic metastable

^{4}\mathrm{H}\mathrm{e}

atoms in a magneto-optical trap. The trapped clouds, containing up to

1.5\ifmmode\times\else\texttimes\fi{}{10}^{8}

atoms of each isotope, are characterized by measuring ions and metastable helium atoms escaping from the trap. Optical pumping of

^{3}\mathrm{H}\mathrm{e}

atoms to a nontrapped hyperfine state is investigated and it is shown that large atom numbers can be confined without additional repumping lasers. Unique possibilities for quantum degeneracy experiments with mixtures of spin-polarized metastable

^{3}\mathrm{H}\mathrm{e}

and

^{4}\mathrm{H}\mathrm{e}

atoms are indicated.

DOI: 10.1103/physrevlett.93.053001

Related papers

Simultaneous magneto-optical trapping of bosonic and fermionic chromium atoms

Radu Chicireanu, A. Pouderous, R. Barbé +5 more

We report on magneto-optical trapping of fermionic $^{53}\mathrm{Cr}$ atoms. A Zeeman-slowed atomic beam provides loading rates up to $3\ifmmode\times\else\texttimes\fi{}{10}^{6}\phantom{\rule{0.3em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$. We present systematic characterization of the magneto-optical trap (MOT). We obtain up to $5\ifmmode\times\else\texttimes\fi{}{10}^{5}$ atoms in the steady-state MOT. The atoms radiatively decay from the excited $P$ state into metastable $D$ states, and, due to the large dipolar magnetic moment of chromium atoms in these states, they can remain magnetically trapped in the quadrupole field gradient of the MOT. We study the accumulation of metastable $^{53}\mathrm{Cr}$ atoms in this magnetic trap. We also report on the simultaneous magneto-optical trapping of bosonic $^{52}\mathrm{Cr}$ and fermionic $^{53}\mathrm{Cr}$ atoms. Finally, we characterize the light-assisted collision losses in this Bose-Fermi cold mixture.We report on magneto-optical trapping of fermionic $^{53}\mathrm{Cr}$ atoms. A Zeeman-slowed atomic beam provides loading rates up to $3\ifmmode\times\else\texttimes\fi{}{10}^{6}\phantom{\rule{0.3em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$. We present systematic characterization of the magneto-optical trap (MOT). We obtain up to $5\ifmmode\times\else\texttimes\fi{}{10}^{5}$ atoms in the steady-state MOT. The atoms radiatively decay from the excited $P$ state into metastable $D$ states, and, due to the large dipolar magnetic moment of chromium atoms in these states, they can remain magnetically trapped in the quadrupole field gradient of the MOT. We study the accumulation of metastable $^{53}\mathrm{Cr}$ atoms in this magnetic trap. We also report on the simultaneous magneto-optical trapping of bosonic $^{52}\mathrm{Cr}$ and fermionic $^{53}\mathrm{Cr}$ atoms. Finally, we characterize the light-assisted collision losses in this Bose-Fermi cold mixture.

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Homonuclear ionizing collisions of laser-cooled metastable helium atoms

R. J. W. Stas, J. M. McNamara, W. Hogervorst +1 more

We present a theoretical and experimental investigation of homonuclear ionizing collisions of laser-cooled metastable $(2\phantom{\rule{0.2em}{0ex}}^{3}S_{1})$ helium atoms, considering both the fermionic $^{3}\mathrm{He}$ and bosonic $^{4}\mathrm{He}$ isotopes. The theoretical description combines quantum threshold behavior, Wigner's spin-conservation rule, and quantum-statistical symmetry requirements in a single-channel model, complementing a more complete close-coupling theory that has been reported for collisions of metastable $^{4}\mathrm{He}$ atoms. The model is supported with measurements (in the absence of light fields) of ionization rates in magneto-optically trapped samples that contain about $3\ifmmode\times\else\texttimes\fi{}{10}^{8}$ atoms of a single isotope. The ionization rates are determined from measurements of trap loss due to light-assisted collisions combined with comparative measurements of the ion production rate in the absence and presence of trapping light. Theory and experiment show good agreement.We present a theoretical and experimental investigation of homonuclear ionizing collisions of laser-cooled metastable $(2\phantom{\rule{0.2em}{0ex}}^{3}S_{1})$ helium atoms, considering both the fermionic $^{3}\mathrm{He}$ and bosonic $^{4}\mathrm{He}$ isotopes. The theoretical description combines quantum threshold behavior, Wigner's spin-conservation rule, and quantum-statistical symmetry requirements in a single-channel model, complementing a more complete close-coupling theory that has been reported for collisions of metastable $^{4}\mathrm{He}$ atoms. The model is supported with measurements (in the absence of light fields) of ionization rates in magneto-optically trapped samples that contain about $3\ifmmode\times\else\texttimes\fi{}{10}^{8}$ atoms of a single isotope. The ionization rates are determined from measurements of trap loss due to light-assisted collisions combined with comparative measurements of the ion production rate in the absence and presence of trapping light. Theory and experiment show good agreement.

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Trapping an isotopic mixture of fermionic 84Rb and bosonic 87Rb atoms

S. G. Crane, Xinxin Zhao, Wayne A. Taylor +1 more

We have simultaneously confined fermionic ${}^{84}\mathrm{Rb}$ and bosonic ${}^{87}\mathrm{Rb}$ atoms in overlapping magneto-optical traps in which radioactive ${}^{84}\mathrm{Rb}$ atoms ${(t}_{1/2}=33$ d) have been trapped. We investigated ${}^{84}\mathrm{Rb}$ trap loss when overlapped with a cloud of ${}^{87}\mathrm{Rb}$ atoms trapped from a background rubidium vapor. Collision loss measurements were taken with $\ensuremath{\sim}5\ifmmode\times\else\texttimes\fi{}{10}^{5}$ and $\ensuremath{\sim}4\ifmmode\times\else\texttimes\fi{}{10}^{7}$ atoms of trapped ${}^{84}\mathrm{Rb}$ and ${}^{87}\mathrm{Rb},$ respectively. We have found a trapping solution for which there is negligible additional trap loss for ${}^{84}\mathrm{Rb}$ due to the presence of ${}^{87}\mathrm{Rb},$ showing that the mixture can be readily prepared for a sympathetic cooling experiment.We have simultaneously confined fermionic ${}^{84}\mathrm{Rb}$ and bosonic ${}^{87}\mathrm{Rb}$ atoms in overlapping magneto-optical traps in which radioactive ${}^{84}\mathrm{Rb}$ atoms ${(t}_{1/2}=33$ d) have been trapped. We investigated ${}^{84}\mathrm{Rb}$ trap loss when overlapped with a cloud of ${}^{87}\mathrm{Rb}$ atoms trapped from a background rubidium vapor. Collision loss measurements were taken with $\ensuremath{\sim}5\ifmmode\times\else\texttimes\fi{}{10}^{5}$ and $\ensuremath{\sim}4\ifmmode\times\else\texttimes\fi{}{10}^{7}$ atoms of trapped ${}^{84}\mathrm{Rb}$ and ${}^{87}\mathrm{Rb},$ respectively. We have found a trapping solution for which there is negligible additional trap loss for ${}^{84}\mathrm{Rb}$ due to the presence of ${}^{87}\mathrm{Rb},$ showing that the mixture can be readily prepared for a sympathetic cooling experiment.

Physical Review AJun 13, 200026 citations

We simultaneously confine fermionic metastable

^{3}\mathrm{H}\mathrm{e}

atoms and bosonic metastable

^{4}\mathrm{H}\mathrm{e}

atoms in a magneto-optical trap. The trapped clouds, containing up to

1.5\ifmmode\times\else\texttimes\fi{}{10}^{8}

atoms of each isotope, are characterized by measuring ions and metastable helium atoms escaping from the trap. Optical pumping of

^{3}\mathrm{H}\mathrm{e}

^{3}\mathrm{H}\mathrm{e}

and

^{4}\mathrm{H}\mathrm{e}

atoms are indicated.

We report on magneto-optical trapping of fermionic

^{53}\mathrm{Cr}

atoms. A Zeeman-slowed atomic beam provides loading rates up to $3\ifmmode\times\else\texttimes\fi{}{10}^{6}\phantom{\rule{0.3em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$. We present systematic characterization of the magneto-optical trap (MOT). We obtain up to $5\ifmmode\times\else\texttimes\fi{}{10}^{5}$ atoms in the steady-state MOT. The atoms radiatively decay from the excited

P

state into metastable

D

states, and, due to the large dipolar magnetic moment of chromium atoms in these states, they can remain magnetically trapped in the quadrupole field gradient of the MOT. We study the accumulation of metastable

^{53}\mathrm{Cr}

atoms in this magnetic trap. We also report on the simultaneous magneto-optical trapping of bosonic

^{52}\mathrm{Cr}

and fermionic

^{53}\mathrm{Cr}

atoms. Finally, we characterize the light-assisted collision losses in this Bose-Fermi cold mixture.

We present a theoretical and experimental investigation of homonuclear ionizing collisions of laser-cooled metastable

(2\phantom{\rule{0.2em}{0ex}}^{3}S_{1})

helium atoms, considering both the fermionic

^{3}\mathrm{He}

and bosonic

^{4}\mathrm{He}

isotopes. The theoretical description combines quantum threshold behavior, Wigner's spin-conservation rule, and quantum-statistical symmetry requirements in a single-channel model, complementing a more complete close-coupling theory that has been reported for collisions of metastable

^{4}\mathrm{He}

atoms. The model is supported with measurements (in the absence of light fields) of ionization rates in magneto-optically trapped samples that contain about $3\ifmmode\times\else\texttimes\fi{}{10}^{8}$ atoms of a single isotope. The ionization rates are determined from measurements of trap loss due to light-assisted collisions combined with comparative measurements of the ion production rate in the absence and presence of trapping light. Theory and experiment show good agreement.

We have simultaneously confined fermionic

{}^{84}\mathrm{Rb}

and bosonic

{}^{87}\mathrm{Rb}

atoms in overlapping magneto-optical traps in which radioactive

{}^{84}\mathrm{Rb}

atoms

{(t}_{1/2}=33

d) have been trapped. We investigated

{}^{84}\mathrm{Rb}

trap loss when overlapped with a cloud of

{}^{87}\mathrm{Rb}

atoms trapped from a background rubidium vapor. Collision loss measurements were taken with $\ensuremath{\sim}5\ifmmode\times\else\texttimes\fi{}{10}^{5}$ and $\ensuremath{\sim}4\ifmmode\times\else\texttimes\fi{}{10}^{7}$ atoms of trapped

{}^{84}\mathrm{Rb}

and

{}^{87}\mathrm{Rb},

respectively. We have found a trapping solution for which there is negligible additional trap loss for

{}^{84}\mathrm{Rb}

due to the presence of

{}^{87}\mathrm{Rb},

showing that the mixture can be readily prepared for a sympathetic cooling experiment.