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

European Quantum Electronics Conference (EQEC)

Trapping and interactions of an ultracold gas of Cs/sub 2/ molecules

Tobias Kraemer, Manfred J. Mark, Jens Herbig, P. Waldburger, Cheng Chin, Hanns-Christoph Naegerl, Rudolf Grimm

Published Jan 18, 2006• 0 citations
Publisher

Abstract

We investigate dynamics and interactions of Cs/sub 2/ dimers in a CO/sub 2/-laser dipole trap. Starting with a Bose-Einstein condensate (BEC) of 2.2*10/sup 5/ Cs atoms, we create ultracold molecules in a single, weakly bound quantum state by sweeping the magnetic field across a narrow Feshbach resonance.
DOI
10.1109/eqec.2005.1567408

Related papers

Vibrational relaxation of ultracold lithium dimers

Jordan M. Gerton, Dmitry Strekalov, Ionuţ D. Prodan +1 more

Summary form only given. Laser cooling and trapping of atoms has enabled some of the most exciting recent advances in atomic physics, including the achievement of Bose-Einstein condensation (BEC). Efforts are now underway to trap ultracold molecules in order to study chemical reactions and to investigate BEC of larger particles. In the atomic BEC experiments, the atoms are cooled to sub-/spl mu/K temperatures so the energy spread of the atoms which are not in the condensate is small (/spl les/20 kHz) and that of the condensate itself is zero. Therefore, a quantum degenerate gas enables an unprecedented level of spectroscopic precision. We report two-photon photoassociation of quantum degenerate /sup 7/Li atoms into the least-bound vibrational level of the ground-state triplet potential of /sup 7/Li/sub 2/. These molecules are magnetically trappable by virtue of their electronic magnetic moment.

Quantum Electronics and Laser Science Conference•Jan 1, 2000•0 citations

PRODUCTION OF LONG-LIVED ULTRACOLD LI2 MOLECULES FROM A FERMI GAS

J. Cubizolles, Thomas Bourdel, S. J. J. M. F. Kokkelmans +2 more

We create weakly bound Li/sub 2/ molecules from a degenerate two component Fermi gas by sweeping a magnetic field across a Feshbach resonance. The atom-molecule transfer efficiency can reach 85% and is studied as a function of magnetic field and initial temperature. The bosonic molecules remain trapped for 0.5 s and their temperature is within a factor of 2 from the Bose-Einstein condensation temperature. A thermodynamical model reproduces qualitatively the experimental findings

Laser Spectroscopy•Feb 1, 2004•1 citation

Dissociation of ultracold molecules with Feshbach resonances

Stephan Dürr, Thomas Volz, Gerhard Rempe

Ultracold molecules are associated from an atomic Bose-Einstein condensate by ramping a magnetic field across a Feshbach resonance. The reverse ramp dissociates the molecules. The kinetic energy released in the dissociation process is used to measure the widths of four Feshbach resonances in $^{87}\mathrm{Rb}$. This method to determine the width works remarkably well for narrow resonances even in the presence of significant magnetic-field noise. In addition, a quasimonoenergetic atomic wave is created by jumping the magnetic field across the Feshbach resonance.

arXiv:cond-mat/0405606•Physical Review A•Sep 8, 2004•79 citations

Preparation of a Pure Molecular Quantum Gas

Jens Herbig, Tobias Kraemer, Michael F. Mark +4 more

An ultracold molecular quantum gas is created by application of a magnetic field sweep across a Feshbach resonance to a Bose-Einstein condensate of cesium atoms. The ability to separate the molecules from the atoms permits direct imaging of the pure molecular sample. Magnetic levitation enables study of the dynamics of the ensemble on extended time scales. We measured ultralow expansion energies in the range of a few nanokelvin for a sample of 3000 molecules. Our observations are consistent with the presence of a macroscopic molecular matter wave.

Science•Aug 26, 2003•411 citations

Molecule formation in ultracold atomic gases

Hutson, J M, Soldan, P H

This review describes recent experimental and theoretical advances in forming molecules in ultracold gases of trapped alkali metal atoms, both by magnetic tuning through Feshbach resonances and by photoassociation. Molecular Bose-Einstein condensation of long-range states of both boson dimers and fermion dimers was achieved in 2002-3. Condensates of boson dimers were found to be short-lived, but long-lived condensates of fermion dimers have been produced. Signatures of triatomic and tetraatomic molecules have recently been observed. Both homonuclear and heteronuclear molecules have been formed by photoassociation, mostly in very high vibrational levels. Recent attempts to produce ultracold molecules in short-range states (low vibrational levels) are described. Experimental and theoretical work on collisions of ultracold molecules is discussed.

•Jul 26, 2006•82 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
Summary form only given. Laser cooling and trapping of atoms has enabled some of the most exciting recent advances in atomic physics, including the achievement of Bose-Einstein condensation (BEC). Efforts are now underway to trap ultracold molecules in order to study chemical reactions and to investigate BEC of larger particles. In the atomic BEC experiments, the atoms are cooled to sub-/spl mu/K temperatures so the energy spread of the atoms which are not in the condensate is small (/spl les/20 kHz) and that of the condensate itself is zero. Therefore, a quantum degenerate gas enables an unprecedented level of spectroscopic precision. We report two-photon photoassociation of quantum degenerate /sup 7/Li atoms into the least-bound vibrational level of the ground-state triplet potential of /sup 7/Li/sub 2/. These molecules are magnetically trappable by virtue of their electronic magnetic moment.
Ultracold molecules are associated from an atomic Bose-Einstein condensate by ramping a magnetic field across a Feshbach resonance. The reverse ramp dissociates the molecules. The kinetic energy released in the dissociation process is used to measure the widths of four Feshbach resonances in 87Rb^{87}\mathrm{Rb}87Rb. This method to determine the width works remarkably well for narrow resonances even in the presence of significant magnetic-field noise. In addition, a quasimonoenergetic atomic wave is created by jumping the magnetic field across the Feshbach resonance.
An ultracold molecular quantum gas is created by application of a magnetic field sweep across a Feshbach resonance to a Bose-Einstein condensate of cesium atoms. The ability to separate the molecules from the atoms permits direct imaging of the pure molecular sample. Magnetic levitation enables study of the dynamics of the ensemble on extended time scales. We measured ultralow expansion energies in the range of a few nanokelvin for a sample of 3000 molecules. Our observations are consistent with the presence of a macroscopic molecular matter wave.
This review describes recent experimental and theoretical advances in forming molecules in ultracold gases of trapped alkali metal atoms, both by magnetic tuning through Feshbach resonances and by photoassociation. Molecular Bose-Einstein condensation of long-range states of both boson dimers and fermion dimers was achieved in 2002-3. Condensates of boson dimers were found to be short-lived, but long-lived condensates of fermion dimers have been produced. Signatures of triatomic and tetraatomic molecules have recently been observed. Both homonuclear and heteronuclear molecules have been formed by photoassociation, mostly in very high vibrational levels. Recent attempts to produce ultracold molecules in short-range states (low vibrational levels) are described. Experimental and theoretical work on collisions of ultracold molecules is discussed.
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.