Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:cond-mat/0510006 · Physical Review A

Metastable helium Bose-Einstein condensate with a large number of atoms

A. S. Tychkov, T. Jeltes, J. M. McNamara, Paul J. J. Tol, Norbert Herschbach, W. Hogervorst, W. Vassen

Published Mar 14, 2006• 41 citations
arXivHTMLPDF

Abstract

We have produced a Bose-Einstein condensate of metastable helium $(^{4}\mathrm{He}^{*})$ containing over $1.5\ifmmode\times\else\texttimes\fi{}{10}^{7}$ atoms, which is a factor of 25 higher than previously achieved. The improved starting conditions for evaporative cooling are obtained by applying one-dimensional Doppler cooling inside a magnetic trap. The same technique is successfully used to cool the spin-polarized fermionic isotope $(^{3}\mathrm{He}^{*})$, for which thermalizing collisions are highly suppressed. Our detection techniques include absorption imaging, time-of-flight measurements on a microchannel plate detector, and ion counting to monitor the formation and decay of the condensate.

DOI
10.1103/physreva.73.031603

Related papers

Rapid generation of metastable helium Bose-Einstein condensates

A. H. Abbas, X. Meng, Rohit Patil +3 more

We report the realization of Bose-Einstein condensation (BEC) of metastable helium atoms using an in-vacuum coil magnetic trap and a crossed-beam optical dipole trap. A quadrupole-Ioffe configuration magnetic trap made from in-vacuum hollow copper tubes provides fast switching times while generating traps with a 10-G bias, without compromising optical access. The bias enables in-trap one-dimensional Doppler cooling to be used, which is the only cooling stage between the magneto-optic trap and the optical dipole trap. This allows direct transfer to the dipole trap without the need for any additional evaporative cooling in the magnetic trap. The entire experimental sequence takes 3.3 s, with essentially pure BECs observed with $\ensuremath{\sim}{10}^{6}$ atoms after evaporative cooling in the dipole trap.

arXiv:2102.10810•Physical Review A•May 21, 2021•4 citations

Evaporative cooling of metastable helium atoms

Paul J. J. Tol, Norbert Herschbach, W. Hogervorst +1 more

Summary form only given. The importance of helium atoms in the metastable state 2/sup 3/S/sub 1/ (He*, lifetime 8000 s) for studies of ultracold atomic clouds in the quantum degeneracy regime has been pointed out. For /sup 4/He* Bose-Einstein condensation (BEC) is expected, whereas the /sup 3/He isotope allows the study of a fermionic system, if the technique of sympathetic cooling is feasible. We plan to reach the BEC transition using forced evaporative cooling in our magnetostatic trap (MST) of cloverleaf geometry.

Conference on Lasers and Electro-Optics•Aug 29, 2005•0 citations

Large atom number Bose-Einstein condensate of sodium

K. M. R. van der Stam, Erik van Ooijen, R. Meppelink +2 more

We describe the setup to create a large Bose-Einstein condensate containing more than 120 x 10(6) atoms. In the experiment a thermal beam is slowed by a Zeeman slower and captured in a dark-spot magneto-optical trap (MOT). A typical dark-spot MOT in our experiments contains 2.0 x 10(10) atoms with a temperature of 320 microK and a density of about 1.0 x 10(11) atoms/cm(3). The sample is spin polarized in a high magnetic field before the atoms are loaded in the magnetic trap. Spin polarizing in a high magnetic field results in an increase in the transfer efficiency by a factor of 2 compared to experiments without spin polarizing. In the magnetic trap the cloud is cooled to degeneracy in 50 s by evaporative cooling. To suppress the three-body losses at the end of the evaporation, the magnetic trap is decompressed in the axial direction.

arXiv:physics/0609028•Review of Scientific Instruments•Jan 1, 2007•66 citations

Fast production of Bose-Einstein condensates of metastable helium

Quentin Bouton, R. Chang, A. L. Hoendervanger +4 more

We report on the Bose-Einstein condensation of metastable $^{4}\mathrm{He}$ atoms using a hybrid approach, consisting of a magnetic quadrupole and an optical dipole trap. In our setup we cross the phase transition with $2\ifmmode\times\else\texttimes\fi{}{10}^{6}$ atoms, and we obtain pure condensates of $5\ifmmode\times\else\texttimes\fi{}{10}^{5}$ atoms in the optical trap. This approach to cooling $^{4}\mathrm{He}$ provides enhanced cycle stability, large optical access to the atoms and results in the production of a condensate every 6 s---a factor 2 faster than the state of the art. This speed-up will significantly reduce the data acquisition time needed for the measurement of many particle correlations, made possible by the ability of metastable helium atoms to be detected individually.

arXiv:1504.06197•Physical Review A•Jun 9, 2015•34 citations

Collisions in a gas of metastable helium near quantum degeneracy

Signe Louise Seidelin

This thesis presents an experimental study of an atomic cloud in the vicinity of Bose-Einstein condensation. The atoms used in our experiment are special in the sense that they are metastable -- we use metastable helium. The metastability opens the door for using new and original detection methods. Due to their internal energy, the atoms can be detected electronically by means of a micro-channel plate. The use of metastable helium is also interesting due of the presence of ionizing collisions in the sample. The He+ ions produced in collisions between the metastable atoms can be detected in real-time, and the ion signal constitutes an alternative and useful diagnostic. In particular, this signal allows one to identify very precisely the Bose-Einstein condensation threshold. One of the advantages of using this signal to probe the cloud, is its ''non-invasive nature: observing the ions does not at all alter the natural evolution of the cloud, in contrast to the ordinary detection technique which consists of releasing the atoms from the trap and then imaging the cloud. In this thesis, by using the new diagnostics based on the ion signal, we have measured some important parameters governing the collisions, and thereby the behavior of the cloud: the ionizing rate constants and the scattering length.

Bulletin of the American Physical Society•May 18, 2005•0 citations

Towards Bose-Einstein condensation with metastable helium atoms

S. Nowak, Antoine Browaeys, J. Poupard +4 more

Summary form only given. Until now Bose-Einstein condensation has only been achieved for atoms in the first group of the periodic table. The goal of our experiment is to obtain this phase transition in a gas of ultra-cold metastable (2 /sup 3/S/sub 1/) helium atoms, using a combination of laser cooling, magnetic trapping and evaporative cooling. Dense cold samples of metastable helium are a well-suited tool for surface potential studies and precision measurements.

Conference on Lasers and Electro-Optics•Jan 1, 2000•0 citations
We have produced a Bose-Einstein condensate of metastable helium (4He∗)(^{4}\mathrm{He}^{*})(4He∗) containing over 1.5\ifmmode×\else\texttimes\fi1071.5\ifmmode\times\else\texttimes\fi{}{10}^{7}1.5\ifmmode×\else\texttimes\fi107 atoms, which is a factor of 25 higher than previously achieved. The improved starting conditions for evaporative cooling are obtained by applying one-dimensional Doppler cooling inside a magnetic trap. The same technique is successfully used to cool the spin-polarized fermionic isotope (3He∗)(^{3}\mathrm{He}^{*})(3He∗), for which thermalizing collisions are highly suppressed. Our detection techniques include absorption imaging, time-of-flight measurements on a microchannel plate detector, and ion counting to monitor the formation and decay of the condensate.
We report the realization of Bose-Einstein condensation (BEC) of metastable helium atoms using an in-vacuum coil magnetic trap and a crossed-beam optical dipole trap. A quadrupole-Ioffe configuration magnetic trap made from in-vacuum hollow copper tubes provides fast switching times while generating traps with a 10-G bias, without compromising optical access. The bias enables in-trap one-dimensional Doppler cooling to be used, which is the only cooling stage between the magneto-optic trap and the optical dipole trap. This allows direct transfer to the dipole trap without the need for any additional evaporative cooling in the magnetic trap. The entire experimental sequence takes 3.3 s, with essentially pure BECs observed with $\ensuremath{\sim}{10}^{6}$ atoms after evaporative cooling in the dipole trap.
Summary form only given. The importance of helium atoms in the metastable state 2/sup 3/S/sub 1/ (He*, lifetime 8000 s) for studies of ultracold atomic clouds in the quantum degeneracy regime has been pointed out. For /sup 4/He* Bose-Einstein condensation (BEC) is expected, whereas the /sup 3/He isotope allows the study of a fermionic system, if the technique of sympathetic cooling is feasible. We plan to reach the BEC transition using forced evaporative cooling in our magnetostatic trap (MST) of cloverleaf geometry.
We describe the setup to create a large Bose-Einstein condensate containing more than 120 x 10(6) atoms. In the experiment a thermal beam is slowed by a Zeeman slower and captured in a dark-spot magneto-optical trap (MOT). A typical dark-spot MOT in our experiments contains 2.0 x 10(10) atoms with a temperature of 320 microK and a density of about 1.0 x 10(11) atoms/cm(3). The sample is spin polarized in a high magnetic field before the atoms are loaded in the magnetic trap. Spin polarizing in a high magnetic field results in an increase in the transfer efficiency by a factor of 2 compared to experiments without spin polarizing. In the magnetic trap the cloud is cooled to degeneracy in 50 s by evaporative cooling. To suppress the three-body losses at the end of the evaporation, the magnetic trap is decompressed in the axial direction.
We report on the Bose-Einstein condensation of metastable 4He^{4}\mathrm{He}4He atoms using a hybrid approach, consisting of a magnetic quadrupole and an optical dipole trap. In our setup we cross the phase transition with $2\ifmmode\times\else\texttimes\fi{}{10}^{6}$ atoms, and we obtain pure condensates of $5\ifmmode\times\else\texttimes\fi{}{10}^{5}$ atoms in the optical trap. This approach to cooling 4He^{4}\mathrm{He}4He provides enhanced cycle stability, large optical access to the atoms and results in the production of a condensate every 6 s---a factor 2 faster than the state of the art. This speed-up will significantly reduce the data acquisition time needed for the measurement of many particle correlations, made possible by the ability of metastable helium atoms to be detected individually.
This thesis presents an experimental study of an atomic cloud in the vicinity of Bose-Einstein condensation. The atoms used in our experiment are special in the sense that they are metastable -- we use metastable helium. The metastability opens the door for using new and original detection methods. Due to their internal energy, the atoms can be detected electronically by means of a micro-channel plate. The use of metastable helium is also interesting due of the presence of ionizing collisions in the sample. The He+ ions produced in collisions between the metastable atoms can be detected in real-time, and the ion signal constitutes an alternative and useful diagnostic. In particular, this signal allows one to identify very precisely the Bose-Einstein condensation threshold. One of the advantages of using this signal to probe the cloud, is its ''non-invasive nature: observing the ions does not at all alter the natural evolution of the cloud, in contrast to the ordinary detection technique which consists of releasing the atoms from the trap and then imaging the cloud. In this thesis, by using the new diagnostics based on the ion signal, we have measured some important parameters governing the collisions, and thereby the behavior of the cloud: the ionizing rate constants and the scattering length.