arXiv:1003.4641 · Physical Review A

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

Guthrie B. Partridge, Jean-Christophe Jaskula, Marie Bonneau, Denis Boiron, Christoph Ira Westbrook

Published May 26, 2010• 20 citations

Abstract

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.

DOI: 10.1103/physreva.81.053631

Related papers

Bose-Einstein condensate of metastable helium for quantum correlation experiments

Michael Keller, Mateusz Kotyrba, Florian Leupold +3 more

arXiv:1406.1322Physical Review ADec 1, 201436 citations

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

A. S. Tychkov, T. Jeltes, J. M. McNamara +4 more

arXiv:cond-mat/0510006Physical Review AMar 14, 200641 citations

An ultracold, optically trapped mixture of 87Rb and metastable 4He atoms

Adonis Silva Flores, Hari Prasad Mishra, W. Vassen +1 more

arXiv:1611.01430The European Physical Journal DMar 1, 20178 citations

Magnetic-field-dependent trap loss of ultracold metastable helium

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

arXiv:1111.5829Physical Review AFeb 14, 201216 citations

Optical traps for Ultracold Metastable Helium atoms

Juliette Simonet

Mar 14, 20114 citations

Simple method for producing Bose-Einstein condensates of metastable helium using a single beam optical dipole trap

Flores, A.S., Mishra, H.P., W. Vassen +1 more

Jan 1, 20154 citations

arXiv:1003.4641 · Physical Review A

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

Guthrie B. Partridge, Jean-Christophe Jaskula, Marie Bonneau, Denis Boiron, Christoph Ira Westbrook

Published May 26, 2010• 20 citations

arXiv HTML PDF

Abstract

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.

DOI: 10.1103/physreva.81.053631

Related papers

Bose-Einstein condensate of metastable helium for quantum correlation experiments

Michael Keller, Mateusz Kotyrba, Florian Leupold +3 more

We report on the realization of Bose-Einstein condensation of metastable helium-4. After exciting helium to its metastable state in a novel pulse-tube cryostat source, the atomic beam is collimated and slowed. We then trap several ${10}^{8}$ atoms in a magneto-optical trap. For subsequent evaporative cooling, the atoms are transferred into a magnetic trap. Degeneracy is achieved with typically a few ${10}^{6}$ atoms. For detection of atomic correlations with high resolution, an ultrafast delay-line detector has been installed. Consisting of four quadrants with independent readout electronics that allow for true simultaneous detection of atoms, the detector is especially suited for quantum correlation experiments that require the detection of correlated subsystems. We expect our setup to allow for the direct demonstration of momentum entanglement in a scenario equivalent to the Einstein-Podolsky-Rosen gedanken experiment. This will pave the way to matter-wave experiments exploiting the peculiarities of quantum correlations.We report on the realization of Bose-Einstein condensation of metastable helium-4. After exciting helium to its metastable state in a novel pulse-tube cryostat source, the atomic beam is collimated and slowed. We then trap several ${10}^{8}$ atoms in a magneto-optical trap. For subsequent evaporative cooling, the atoms are transferred into a magnetic trap. Degeneracy is achieved with typically a few ${10}^{6}$ atoms. For detection of atomic correlations with high resolution, an ultrafast delay-line detector has been installed. Consisting of four quadrants with independent readout electronics that allow for true simultaneous detection of atoms, the detector is especially suited for quantum correlation experiments that require the detection of correlated subsystems. We expect our setup to allow for the direct demonstration of momentum entanglement in a scenario equivalent to the Einstein-Podolsky-Rosen gedanken experiment. This will pave the way to matter-wave experiments exploiting the peculiarities of quantum correlations.

arXiv:1406.1322Physical Review ADec 1, 201436 citations

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

A. S. Tychkov, T. Jeltes, J. M. McNamara +4 more

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.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.

arXiv:cond-mat/0510006Physical Review AMar 14, 200641 citations

An ultracold, optically trapped mixture of 87Rb and metastable 4He atoms

Adonis Silva Flores, Hari Prasad Mishra, W. Vassen +1 more

We report on the realization of an ultracold (<25 μK) mixture of rubidium (87Rb) and metastable triplet helium (4He) in an optical dipole trap. Our scheme involves laser cooling in a dual-species magneto-optical trap, simultaneous MW- and RF-induced forced evaporative cooling in a quadrupole magnetic trap, and transfer to a single-beam optical dipole trap. We observe long trapping lifetimes for the doubly spin-stretched spin-state mixture and measure much shorter lifetimes for other spin-state combinations. We discuss prospects for realizing quantum degenerate mixtures of alkali-metal and metastable helium atoms.We report on the realization of an ultracold (<25 μK) mixture of rubidium (87Rb) and metastable triplet helium (4He) in an optical dipole trap. Our scheme involves laser cooling in a dual-species magneto-optical trap, simultaneous MW- and RF-induced forced evaporative cooling in a quadrupole magnetic trap, and transfer to a single-beam optical dipole trap. We observe long trapping lifetimes for the doubly spin-stretched spin-state mixture and measure much shorter lifetimes for other spin-state combinations. We discuss prospects for realizing quantum degenerate mixtures of alkali-metal and metastable helium atoms.

arXiv:1611.01430The European Physical Journal DMar 1, 20178 citations

Magnetic-field-dependent trap loss of ultracold metastable helium

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

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.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.

arXiv:1111.5829Physical Review AFeb 14, 201216 citations

Optical traps for Ultracold Metastable Helium atoms

Juliette Simonet

The thematics treated in this manuscript illustrate two specificities of ultracold metastable Helium gases: the ability to compare experimental measurement with precise theoretical evaluations (simplicity of the atomic structure) and to easily detect products of Penning ionisations. We present the building and the characterisation of a novel magnetic trap with large optical access, allowing to combine the production of a Bose-Einstein condensate with its in situ loading into a 3D optical lattice. The theoretical fundaments of the experiments planned in those optical potentials are then detailed. In a crossed dipole trap, the influence of the magnetic field, now a free parameter, on the Penning collision rates can be measured and compared to a new theoretical evaluation. Concerning Helium in optical lattices, two subjects are developped: the effect of the confinement on the inelastic Penning collisions (1D optical lattice) and the modelisation of the Penning losses via a dissipative Bose-Hubbard model (3D lattice). Finally we present the first direct measurement of the dipolar magnetic transition 23S1 to 23P2, linking the singlet and triplet families in Helium 4. This spectroscopy experiment, realised in collaboration with the group of W. Vassen (LaserLab - Amsterdam), combines cold atoms knowledge with the frequency comb technique, in order to reach an accuracy of 5 kHz.The thematics treated in this manuscript illustrate two specificities of ultracold metastable Helium gases: the ability to compare experimental measurement with precise theoretical evaluations (simplicity of the atomic structure) and to easily detect products of Penning ionisations. We present the building and the characterisation of a novel magnetic trap with large optical access, allowing to combine the production of a Bose-Einstein condensate with its in situ loading into a 3D optical lattice. The theoretical fundaments of the experiments planned in those optical potentials are then detailed. In a crossed dipole trap, the influence of the magnetic field, now a free parameter, on the Penning collision rates can be measured and compared to a new theoretical evaluation. Concerning Helium in optical lattices, two subjects are developped: the effect of the confinement on the inelastic Penning collisions (1D optical lattice) and the modelisation of the Penning losses via a dissipative Bose-Hubbard model (3D lattice). Finally we present the first direct measurement of the dipolar magnetic transition 23S1 to 23P2, linking the singlet and triplet families in Helium 4. This spectroscopy experiment, realised in collaboration with the group of W. Vassen (LaserLab - Amsterdam), combines cold atoms knowledge with the frequency comb technique, in order to reach an accuracy of 5 kHz.

Mar 14, 20114 citations

Simple method for producing Bose-Einstein condensates of metastable helium using a single beam optical dipole trap

Flores, A.S., Mishra, H.P., W. Vassen +1 more

We demonstrate a simple scheme to reach Bose–Einstein condensation (BEC) of metastable triplet helium atoms using a single-beam optical dipole trap with moderate power of less than 3 W. Our scheme is based on RF-induced evaporative cooling in a quadrupole magnetic trap and transfer to a single-beam optical dipole trap that is located below the magnetic trap center. We transfer $1\times 10^6$ atoms into the optical dipole trap, with an initial temperature of $$14\,\upmu\hbox{K}$$ , and observe efficient forced evaporative cooling both in a hybrid trap, in which the quadrupole magnetic trap operates just below the levitation gradient, and in the pure optical dipole trap, reaching the onset of BEC with $2\times 10^5$ atoms and a pure BEC of $5\times 10^4$ atoms. Our work shows that a single-beam hybrid trap can be applied for a light atom, for which evaporative cooling in the quadrupole magnetic trap is strongly limited by Majorana spin-flips, and the very small levitation gradient limits the axial confinement in the hybrid trap.We demonstrate a simple scheme to reach Bose–Einstein condensation (BEC) of metastable triplet helium atoms using a single-beam optical dipole trap with moderate power of less than 3 W. Our scheme is based on RF-induced evaporative cooling in a quadrupole magnetic trap and transfer to a single-beam optical dipole trap that is located below the magnetic trap center. We transfer $$1\times 10^6$$ atoms into the optical dipole trap, with an initial temperature of $$14\,\upmu\hbox{K}$$ , and observe efficient forced evaporative cooling both in a hybrid trap, in which the quadrupole magnetic trap operates just below the levitation gradient, and in the pure optical dipole trap, reaching the onset of BEC with $$2\times 10^5$$ atoms and a pure BEC of $$5\times 10^4$$ atoms. Our work shows that a single-beam hybrid trap can be applied for a light atom, for which evaporative cooling in the quadrupole magnetic trap is strongly limited by Majorana spin-flips, and the very small levitation gradient limits the axial confinement in the hybrid trap.

Jan 1, 20154 citations

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. We also confirm the instability of certain spin-state combinations of

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

{10}^{8}

atoms in a magneto-optical trap. For subsequent evaporative cooling, the atoms are transferred into a magnetic trap. Degeneracy is achieved with typically a few

{10}^{6}

atoms. For detection of atomic correlations with high resolution, an ultrafast delay-line detector has been installed. Consisting of four quadrants with independent readout electronics that allow for true simultaneous detection of atoms, the detector is especially suited for quantum correlation experiments that require the detection of correlated subsystems. We expect our setup to allow for the direct demonstration of momentum entanglement in a scenario equivalent to the Einstein-Podolsky-Rosen gedanken experiment. This will pave the way to matter-wave experiments exploiting the peculiarities of quantum correlations.

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.

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.

1\times 10^6

atoms into the optical dipole trap, with an initial temperature of $$14\,\upmu\hbox{K}$$ , and observe efficient forced evaporative cooling both in a hybrid trap, in which the quadrupole magnetic trap operates just below the levitation gradient, and in the pure optical dipole trap, reaching the onset of BEC with

2\times 10^5

atoms and a pure BEC of

5\times 10^4

atoms. Our work shows that a single-beam hybrid trap can be applied for a light atom, for which evaporative cooling in the quadrupole magnetic trap is strongly limited by Majorana spin-flips, and the very small levitation gradient limits the axial confinement in the hybrid trap.