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:2211.07111 · Physical Review A

Production of a highly degenerate Fermi gas of metastable He3 atoms

Kieran F. Thomas, Zhuoxian Ou, B. M. Henson, Angela A. Baiju, Sean S. Hodgman, Andrew G. Truscott

Published Mar 15, 2023• 6 citations
arXivHTMLPDF

Abstract

We report on the achievement of quantum degeneracy in both components of a Bose-Fermi mixture of metastable helium atoms, $^{4}\mathrm{He}^{*}$ and $^{3}\mathrm{He}^{*}$. Degeneracy is achieved via Doppler cooling and forced evaporation for $^{4}\mathrm{He}^{*}$, and sympathetically cooling $^{3}\mathrm{He}^{*}$ with $^{4}\mathrm{He}^{*}$. We discuss our modified implementation, along with the high versatility of our system. This technique is able to produce a degenerate Fermi gas with a minimum reduced temperature of $T/{T}_{F}=0.14(1)$, consisting of $2.5\ifmmode\times\else\texttimes\fi{}{10}^{4}$ $^{3}\mathrm{He}^{*}$ atoms. Due to the high internal energy of both isotopes single atom detection is possible, opening the possibility of a large number of experiments into Bose-Fermi mixtures.

DOI
10.1103/physreva.107.033313

Related papers

Degenerate Bose-Fermi Mixture of Metastable Atoms

J. M. McNamara, T. Jeltes, A. S. Tychkov +2 more

We report the observation of simultaneous quantum degeneracy in a dilute gaseous Bose-Fermi mixture of metastable atoms. Sympathetic cooling of helium-3 (fermion) by helium-4 (boson), both in the lowest triplet state, allows us to produce ensembles containing more than 10(6) atoms of each isotope at temperatures below 1 microK, and achieve a fermionic degeneracy parameter of T/TF = 0.45. Because of their high internal energy, the detection of individual metastable atoms with subnanosecond time resolution is possible, permitting the study of bosonic and fermionic quantum gases with unprecedented precision. This may lead to metastable helium becoming the mainstay of quantum atom optics.

arXiv:cond-mat/0606638•Physical Review Letters•Aug 24, 2006•99 citations

Production of a degenerate Fermi gas of metastable helium-3 atoms

W. Vassen, T. Jeltes, McNamara, J. M. +1 more

We give an overview of the experiments at the Laser Centre of the Vrije Universiteit in Amsterdam on ultracold gases of metastable helium-4 and helium-3 as well as mixtures of both isotopes. We describe our experimental setup and discuss our experiments on Bose-Einstein condensation of 4He* (more than 10 million atoms in a BEC) and sympathetic cooling of 3He* towards Fermi degeneracy (more than 1 million atoms below the Fermi temperature as well as realization of a degenerate boson-fermion mixture). We also present our results on Penning Ionization in ~1 mK clouds containing a single isotope (homonuclear losses) or a mixture of both isotopes (heteronuclear losses).

arXiv:cond-mat/0610414•Oct 16, 2006•0 citations

Experiments with Ultracold Quantum-degenerate Fermionic Lithium Atoms

Wolfgang Ketterle

Experimental methods of laser and evaporative cooling, used in the production of atomic Bose-Einstein condensates have recently been extended to realize quantum degeneracy in trapped Fermi gases. Fermi gases are a new rich system to explore the implications of Pauli exclusion on scattering properties of the system, and ultimately fermionic superfluidity. We have produced a new macroscopic quantum system, in which a degenerate Li-6 Fermi gas coexists with a large and stable Na-23 BEC. This was accomplished using inter-species sympathetic cooling of fermionic 6Li in a thermal bath of bosonic Na-23. We have achieved high numbers of both fermions (less than 10(exp 5) and bosons (less than 10(exp 6), and Li-6 quantum degeneracy corresponding to one half of the Fermi temperature. This is the first time that a Fermi sea was produced with a condensate as a "refrigerator".

•Jan 1, 2003•0 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.

arXiv:cond-mat/0510006•Physical Review A•Mar 14, 2006•41 citations

ULTRACOLD METASTABLE HELIUM-4 AND HELIUM-3 GASES

W. Vassen, T. Jeltes, J. M. MCNAMARA +10 more

We discuss our work to obtain a condensate containing more than 107 atoms and the first degenerate Fermi gas in a metastable state. Sympathetic cooling with Helium-4 is used to cool 106 Helium-3 atoms to a temperature T/TF < 0.5. The ultracold bosonic and fermionic gases have been used to observe the Hanbury Brown and Twiss effect for both isotopes, showing bunching for the bosons and antibunching for the fermions. A proposal for high resolution spectroscopy at 1.557 μm, connecting both metastable states directly, is discussed at the end.

Laser Spectroscopy•Apr 1, 2008•1 citation

Quantum Degenerate Two-Species Fermi-Fermi Mixture Coexisting with a Bose-Einstein Condensate

M. Taglieber, A.-C. Voigt, T. Aoki +2 more

We report on the generation of a quantum degenerate Fermi-Fermi mixture of two different atomic species. The quantum degenerate mixture is realized employing sympathetic cooling of fermionic 6Li and 40K gases by an evaporatively cooled bosonic 87Rb gas. We describe the combination of trapping and cooling methods that proved crucial to successfully cool the mixture. In particular, we study the last part of the cooling process and show that the efficiency of sympathetic cooling of the 6Li gas by 87Rb is increased by the presence of 40K through catalytic cooling. Because of the differing physical properties of the two components, the quantum degenerate 6Li-40K Fermi-Fermi mixture is an excellent candidate for a stable, heteronuclear system allowing the study of several so far unexplored types of quantum matter.

arXiv:0710.2779•Physical Review Letters•Jan 4, 2008•265 citations
We report on the achievement of quantum degeneracy in both components of a Bose-Fermi mixture of metastable helium atoms, 4He∗^{4}\mathrm{He}^{*}4He∗ and 3He∗^{3}\mathrm{He}^{*}3He∗. Degeneracy is achieved via Doppler cooling and forced evaporation for 4He∗^{4}\mathrm{He}^{*}4He∗, and sympathetically cooling 3He∗^{3}\mathrm{He}^{*}3He∗ with 4He∗^{4}\mathrm{He}^{*}4He∗. We discuss our modified implementation, along with the high versatility of our system. This technique is able to produce a degenerate Fermi gas with a minimum reduced temperature of T/TF=0.14(1)T/{T}_{F}=0.14(1)T/TF​=0.14(1), consisting of 2.5\ifmmode×\else\texttimes\fi1042.5\ifmmode\times\else\texttimes\fi{}{10}^{4}2.5\ifmmode×\else\texttimes\fi104 3He∗^{3}\mathrm{He}^{*}3He∗ atoms. Due to the high internal energy of both isotopes single atom detection is possible, opening the possibility of a large number of experiments into Bose-Fermi mixtures.
We report the observation of simultaneous quantum degeneracy in a dilute gaseous Bose-Fermi mixture of metastable atoms. Sympathetic cooling of helium-3 (fermion) by helium-4 (boson), both in the lowest triplet state, allows us to produce ensembles containing more than 10(6) atoms of each isotope at temperatures below 1 microK, and achieve a fermionic degeneracy parameter of T/TF = 0.45. Because of their high internal energy, the detection of individual metastable atoms with subnanosecond time resolution is possible, permitting the study of bosonic and fermionic quantum gases with unprecedented precision. This may lead to metastable helium becoming the mainstay of quantum atom optics.
We give an overview of the experiments at the Laser Centre of the Vrije Universiteit in Amsterdam on ultracold gases of metastable helium-4 and helium-3 as well as mixtures of both isotopes. We describe our experimental setup and discuss our experiments on Bose-Einstein condensation of 4He* (more than 10 million atoms in a BEC) and sympathetic cooling of 3He* towards Fermi degeneracy (more than 1 million atoms below the Fermi temperature as well as realization of a degenerate boson-fermion mixture). We also present our results on Penning Ionization in ~1 mK clouds containing a single isotope (homonuclear losses) or a mixture of both isotopes (heteronuclear losses).
Experimental methods of laser and evaporative cooling, used in the production of atomic Bose-Einstein condensates have recently been extended to realize quantum degeneracy in trapped Fermi gases. Fermi gases are a new rich system to explore the implications of Pauli exclusion on scattering properties of the system, and ultimately fermionic superfluidity. We have produced a new macroscopic quantum system, in which a degenerate Li-6 Fermi gas coexists with a large and stable Na-23 BEC. This was accomplished using inter-species sympathetic cooling of fermionic 6Li in a thermal bath of bosonic Na-23. We have achieved high numbers of both fermions (less than 10(exp 5) and bosons (less than 10(exp 6), and Li-6 quantum degeneracy corresponding to one half of the Fermi temperature. This is the first time that a Fermi sea was produced with a condensate as a "refrigerator".
We have produced a Bose-Einstein condensate of metastable helium (4He∗)(^{4}\mathrm{He}^{*})(4He∗) 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 (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 discuss our work to obtain a condensate containing more than 107 atoms and the first degenerate Fermi gas in a metastable state. Sympathetic cooling with Helium-4 is used to cool 106 Helium-3 atoms to a temperature T/TF < 0.5. The ultracold bosonic and fermionic gases have been used to observe the Hanbury Brown and Twiss effect for both isotopes, showing bunching for the bosons and antibunching for the fermions. A proposal for high resolution spectroscopy at 1.557 μm, connecting both metastable states directly, is discussed at the end.
We report on the generation of a quantum degenerate Fermi-Fermi mixture of two different atomic species. The quantum degenerate mixture is realized employing sympathetic cooling of fermionic 6Li and 40K gases by an evaporatively cooled bosonic 87Rb gas. We describe the combination of trapping and cooling methods that proved crucial to successfully cool the mixture. In particular, we study the last part of the cooling process and show that the efficiency of sympathetic cooling of the 6Li gas by 87Rb is increased by the presence of 40K through catalytic cooling. Because of the differing physical properties of the two components, the quantum degenerate 6Li-40K Fermi-Fermi mixture is an excellent candidate for a stable, heteronuclear system allowing the study of several so far unexplored types of quantum matter.