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:1111.5829 · Physical Review A

Magnetic-field-dependent trap loss of ultracold metastable helium

Joseph Steven Borbely, Rob van Rooij, Steven Knoop, W. Vassen

Published Feb 14, 2012• 16 citations
arXivHTMLPDF

Abstract

We have experimentally studied the magnetic-field dependence of the decay of a Bose-Einstein condensate of metastable ${}^{4}$He atoms confined in an optical dipole trap, for atoms in the $m=+1$ and $m=\ensuremath{-}1$ magnetic substates, and up to 450 G. Our measurements confirm longstanding calculations of the two-body loss rate coefficient that show an increase above 50 G. We demonstrate that for $m=\ensuremath{-}1$ atoms decay is due to three-body recombination only, with a three-body loss rate coefficient of $6.5{(0.4)}_{\mathrm{stat}}{(0.6)}_{\mathrm{sys}}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}27}$ cm${}^{6}$s${}^{\ensuremath{-}1}$, which is interesting in the context of universal few-body theory. We have also searched for a recently predicted $d$-wave Feshbach resonance, but did not observe it.

DOI
10.1103/physreva.85.022706

Related papers

Bose-Einstein condensation and spin mixtures of optically trapped metastable helium

Guthrie B. Partridge, Jean-Christophe Jaskula, Marie Bonneau +2 more

We report the realization of a Bose-Einstein condensate of metastable helium-$4$ atoms ($^{4}\mathrm{He}$${}^{*}$) in an all-optical potential. Up to $10$${}^{5}$ spin-polarized $^{4}\mathrm{He}$${}^{*}$ atoms are condensed in an optical dipole trap formed from a single, focused, vertically propagating far-off-resonance laser beam. The vertical trap geometry is chosen to best match the resolution characteristics of a delay-line anode microchannel plate detector capable of registering single He${}^{*}$ atoms. We also confirm the instability of certain spin-state combinations of $^{4}\mathrm{He}$${}^{*}$ to two-body inelastic processes, which necessarily affects the scope of future experiments using optically trapped spin mixtures. In order to better quantify this constraint, we measure spin-state-resolved two-body inelastic loss rate coefficients in the optical trap.

arXiv:1003.4641•Physical Review A•May 26, 2010•20 citations

Measurement of inelastic losses in a sample of ultracold Rb85

P. A. Altin, Nicholas P. Robins, Rachel Poldy +4 more

We report on measurements of inelastic loss processes in ultracold $^{85}\mathrm{Rb}$ $|F=2\ensuremath{\rangle}$ atoms. Our apparatus creates ultracold $^{85}\mathrm{Rb}$ clouds by sympathetic cooling with a $^{87}\mathrm{Rb}$ reservoir in a quadrupole-Ioffe magnetic trap and subsequently in a weak, large-volume optical dipole trap. We demonstrate strong sympathetic cooling of $^{85}\mathrm{Rb}$ in the magnetic trap, increasing its phase-space density by three orders of magnitude with no detectable loss in number. Ultracold samples created in this way are used to observe the variation of inelastic loss in $^{85}\mathrm{Rb}$ $|F=2, {m}_{F}=\ensuremath{-}2\ensuremath{\rangle}$ clouds as a function of magnetic field near the $155$-G Feshbach resonance and to measure the decay due to inelastic losses in all five Zeeman sublevels of the $F=2$ manifold, finding a particularly high three-body recombination rate in the lowest energy state. We have also observed and characterized a previously unobserved loss feature at $219.9(1)$ G with a width of $0.28(6)$ G, which we associate with a narrow Feshbach resonance predicted by theory.

arXiv:0902.2229•Physical Review A•Jan 29, 2010•10 citations

Magnetic field dependence of the dynamics of Rb87 spin-2 Bose-Einstein condensates

T. Kuwamoto, K. Araki, T. Eno +1 more

We experimentally studied the spin-dependent collision dynamics of $^{87}\mathrm{Rb}$ spin-2 Bose-Einstein condensates confined in an optical trap. The condensed atoms were initially populated in the $\ensuremath{\mid}F=2,{m}_{F}=0⟩$ state, and their time evolutions in the trap were measured in the presence of external magnetic field strengths ranging from 0.1 to $3.0\phantom{\rule{0.3em}{0ex}}\mathrm{G}$. The atom loss rate due to inelastic two-body collisions was found to be $1.4(2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13}\phantom{\rule{0.3em}{0ex}}{\text{cm}}^{3}\phantom{\rule{0.3em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$. Spin mixing in the $F=2$ manifold developed dramatically for the first few tens of milliseconds, and the oscillations in the population distribution between different magnetic components were observed over a limited range of magnetic field strengths. The antiferromagnetic property of this system was deduced from the magnetic field dependence on the evolution of relative populations for each ${m}_{F}$ component.

Physical Review A•Jun 8, 2004•172 citations

Ultracold chromium atoms: from Feshbach resonances to a dipolar Bose–Einstein condensate

J. Stühler, Axel Griesmaier, Jörg Werner +3 more

We report on experiments with ultracold chromium atoms. Preparing a cloud of 52Cr atoms in a crossed optical dipole trap (CODT) and applying magnetic fields between 4 and 600 G, we observe 14 Feshbach resonances by the occurrence of increased atom loss at distinct magnetic field values. A comparison with theory taking only dipole–dipole coupling into account shows very good agreement between experimental and theoretical resonance positions and allows us to extract the s-wave scattering lengths a 6=112(14) a 0, a 4= 58(6) a 0, a 2=−7(20) a 0 of the involved molecular potentials as well as the dispersion coefficients C 6= 733(70) au and au. The strongest resonance at 589 G has a calculated width of 1.7 G and reveals a three-body loss coefficient below L 3, max∼3×10−36 m6 s−1. Further evaporative cooling within the CODT leads to the formation of a Bose–Einstein condensate (BEC) with up to 100 000 condensed atoms. The magnetic dipole–dipole interaction between the Cr atoms is so strong that, as a first mechanical manifestation of dipole–dipole interaction, we observe a modification of the condensate expansion which depends on the alignment of the atomic magnetic dipoles with respect to the axis of the CODT. This magnetostrictive effect is in very good agreement with the theory of dipolar quantum gases and shows that a Cr-BEC is an excellent model system to study dipole–dipole interactions in degenerate quantum gases.

Journal of Modern Optics•Aug 23, 2006•10 citations

Magnetic Field Dependence of Ultracold Inelastic Collisions near a Feshbach Resonance

Jacob Roberts, N. R. Claussen, Simon L. Cornish +1 more

Inelastic collision rates for ultracold 85 Rb atoms in the F=2, m f =-2 state have been measured as a function of magnetic field.At 250 Gauss (G), the two-and three-body loss rates were measured to be K 2 =1.87±0.95±0.19x 10 -14 cm 3 /s and K 3 =4.24+0.70 -0.29 ±0.85 x 10 -25 cm 6 /s respectively.As the magnetic field is decreased from 250 G towards a Feshbach resonance at 155 G, the inelastic rates decrease to a minimum and then increase dramatically, peaking at the Feshbach resonance.Both two-and three-body losses are important, and individual contributions have been compared with theory.

WORLD SCIENTIFIC eBooks•Jan 1, 2008•7 citations

Nonexponential one-body loss in a Bose-Einstein condensate

Steven Knoop, Joseph Steven Borbely, Rob van Rooij +1 more

We have studied the decay of a Bose-Einstein condensate (BEC) of metastable helium atoms in an optical dipole trap. In the regime where two- and three-body losses can be neglected we show that the Bose-Einstein condensate and the thermal cloud show fundamentally different decay characteristics. The total number of atoms decays exponentially with time constant $\ensuremath{\tau}$; however, the thermal cloud decays exponentially with time constant $\frac{4}{3}\ensuremath{\tau}$ and the condensate decays much faster, and nonexponentially. We show that this behavior, which should be present for all BECs in thermal equilibrium with a considerable thermal fraction, is due to a transfer of atoms from the condensate to the thermal cloud during its decay.

arXiv:1112.4754•Physical Review A•Feb 14, 2012•9 citations
We have experimentally studied the magnetic-field dependence of the decay of a Bose-Einstein condensate of metastable 4{}^{4}4He atoms confined in an optical dipole trap, for atoms in the m=+1m=+1m=+1 and m=\ensuremath−1m=\ensuremath{-}1m=\ensuremath−1 magnetic substates, and up to 450 G. Our measurements confirm longstanding calculations of the two-body loss rate coefficient that show an increase above 50 G. We demonstrate that for m=\ensuremath−1m=\ensuremath{-}1m=\ensuremath−1 atoms decay is due to three-body recombination only, with a three-body loss rate coefficient of 6.5(0.4)stat(0.6)sys\ifmmode×\else\texttimes\fi10\ensuremath−276.5{(0.4)}_{\mathrm{stat}}{(0.6)}_{\mathrm{sys}}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}27}6.5(0.4)stat​(0.6)sys​\ifmmode×\else\texttimes\fi10\ensuremath−27 cm6{}^{6}6s\ensuremath−1{}^{\ensuremath{-}1}\ensuremath−1, which is interesting in the context of universal few-body theory. We have also searched for a recently predicted ddd-wave Feshbach resonance, but did not observe it.
We report the realization of a Bose-Einstein condensate of metastable helium-444 atoms (4He^{4}\mathrm{He}4He∗{}^{*}∗) in an all-optical potential. Up to 1010105{}^{5}5 spin-polarized 4He^{4}\mathrm{He}4He∗{}^{*}∗ atoms are condensed in an optical dipole trap formed from a single, focused, vertically propagating far-off-resonance laser beam. The vertical trap geometry is chosen to best match the resolution characteristics of a delay-line anode microchannel plate detector capable of registering single He∗{}^{*}∗ atoms. We also confirm the instability of certain spin-state combinations of 4He^{4}\mathrm{He}4He∗{}^{*}∗ to two-body inelastic processes, which necessarily affects the scope of future experiments using optically trapped spin mixtures. In order to better quantify this constraint, we measure spin-state-resolved two-body inelastic loss rate coefficients in the optical trap.
We report on measurements of inelastic loss processes in ultracold 85Rb^{85}\mathrm{Rb}85Rb $|F=2\ensuremath{\rangle}$ atoms. Our apparatus creates ultracold 85Rb^{85}\mathrm{Rb}85Rb clouds by sympathetic cooling with a 87Rb^{87}\mathrm{Rb}87Rb reservoir in a quadrupole-Ioffe magnetic trap and subsequently in a weak, large-volume optical dipole trap. We demonstrate strong sympathetic cooling of 85Rb^{85}\mathrm{Rb}85Rb in the magnetic trap, increasing its phase-space density by three orders of magnitude with no detectable loss in number. Ultracold samples created in this way are used to observe the variation of inelastic loss in 85Rb^{85}\mathrm{Rb}85Rb $|F=2, {m}_{F}=\ensuremath{-}2\ensuremath{\rangle}$ clouds as a function of magnetic field near the 155155155-G Feshbach resonance and to measure the decay due to inelastic losses in all five Zeeman sublevels of the F=2F=2F=2 manifold, finding a particularly high three-body recombination rate in the lowest energy state. We have also observed and characterized a previously unobserved loss feature at 219.9(1)219.9(1)219.9(1) G with a width of 0.28(6)0.28(6)0.28(6) G, which we associate with a narrow Feshbach resonance predicted by theory.
We experimentally studied the spin-dependent collision dynamics of 87Rb^{87}\mathrm{Rb}87Rb spin-2 Bose-Einstein condensates confined in an optical trap. The condensed atoms were initially populated in the $\ensuremath{\mid}F=2,{m}_{F}=0⟩$ state, and their time evolutions in the trap were measured in the presence of external magnetic field strengths ranging from 0.1 to 3.0G3.0\phantom{\rule{0.3em}{0ex}}\mathrm{G}3.0G. The atom loss rate due to inelastic two-body collisions was found to be $1.4(2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13}\phantom{\rule{0.3em}{0ex}}{\text{cm}}^{3}\phantom{\rule{0.3em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$. Spin mixing in the F=2F=2F=2 manifold developed dramatically for the first few tens of milliseconds, and the oscillations in the population distribution between different magnetic components were observed over a limited range of magnetic field strengths. The antiferromagnetic property of this system was deduced from the magnetic field dependence on the evolution of relative populations for each mF{m}_{F}mF​ component.
We report on experiments with ultracold chromium atoms. Preparing a cloud of 52Cr atoms in a crossed optical dipole trap (CODT) and applying magnetic fields between 4 and 600 G, we observe 14 Feshbach resonances by the occurrence of increased atom loss at distinct magnetic field values. A comparison with theory taking only dipole–dipole coupling into account shows very good agreement between experimental and theoretical resonance positions and allows us to extract the s-wave scattering lengths a 6=112(14) a 0, a 4= 58(6) a 0, a 2=−7(20) a 0 of the involved molecular potentials as well as the dispersion coefficients C 6= 733(70) au and au. The strongest resonance at 589 G has a calculated width of 1.7 G and reveals a three-body loss coefficient below L 3, max∼3×10−36 m6 s−1. Further evaporative cooling within the CODT leads to the formation of a Bose–Einstein condensate (BEC) with up to 100 000 condensed atoms. The magnetic dipole–dipole interaction between the Cr atoms is so strong that, as a first mechanical manifestation of dipole–dipole interaction, we observe a modification of the condensate expansion which depends on the alignment of the atomic magnetic dipoles with respect to the axis of the CODT. This magnetostrictive effect is in very good agreement with the theory of dipolar quantum gases and shows that a Cr-BEC is an excellent model system to study dipole–dipole interactions in degenerate quantum gases.
Inelastic collision rates for ultracold 85 Rb atoms in the F=2, m f =-2 state have been measured as a function of magnetic field.At 250 Gauss (G), the two-and three-body loss rates were measured to be K 2 =1.87±0.95±0.19x 10 -14 cm 3 /s and K 3 =4.24+0.70 -0.29 ±0.85 x 10 -25 cm 6 /s respectively.As the magnetic field is decreased from 250 G towards a Feshbach resonance at 155 G, the inelastic rates decrease to a minimum and then increase dramatically, peaking at the Feshbach resonance.Both two-and three-body losses are important, and individual contributions have been compared with theory.
We have studied the decay of a Bose-Einstein condensate (BEC) of metastable helium atoms in an optical dipole trap. In the regime where two- and three-body losses can be neglected we show that the Bose-Einstein condensate and the thermal cloud show fundamentally different decay characteristics. The total number of atoms decays exponentially with time constant $\ensuremath{\tau}$; however, the thermal cloud decays exponentially with time constant $\frac{4}{3}\ensuremath{\tau}$ and the condensate decays much faster, and nonexponentially. We show that this behavior, which should be present for all BECs in thermal equilibrium with a considerable thermal fraction, is due to a transfer of atoms from the condensate to the thermal cloud during its decay.