Association of molecules using a resonantly modulated magnetic field

Hanna, Thomas M.; Köhler, Thorsten; Burnett, K.

doi:10.1103/physreva.75.013606

Cited by 41 publications

(68 citation statements)

References 38 publications

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“…The magnetic field is then rapidly turned off to image the atoms with standard absorption imaging technique. If the modulation frequency ν is close to the binding energy value, E b ≃ hν, the oscillating magnetic field couples atom pairs to molecules [22]. The atoms are converted into molecules, and the resulting association is detected as resonant loss in the atom number.…”

Section: Binding Energy Measurements and Determination Of The Scmentioning

confidence: 99%

“…This technique, previously applied to a 85 Rb atomic sample [15] and to a 85 Rb-87 Rb mixture [16], has the advantage to determine binding energies of weakly bound molecules to within a few percent. The oscillating magnetic field stimulates a transition between an atom pair and a molecule for a modulation frequency resonant to E b /h [15,22], where h is the Planck constant.…”

Section: Binding Energy Measurements and Determination Of The Scmentioning

confidence: 99%

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Determination of atomic scattering lengths from measurements of molecular binding energies near Feshbach resonances

et al. 2009

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We present an analytic model to calculate the atomic scattering length near a Feshbach resonance from data on the molecular binding energy. Our approach considers finite-range square-well potentials and can be applied near broad, narrow, or even overlapping Feshbach resonances. We test our model on Cs2 Feshbach molecules. We measure the binding energy using magnetic-field modulation spectroscopy in a range where one broad and two narrow Feshbach resonances overlap. From the data we accurately determine the Cs atomic scattering length and the positions and widths of two particular resonances.

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Section: Binding Energy Measurements and Determination Of The Scmentioning

confidence: 99%

Section: Binding Energy Measurements and Determination Of The Scmentioning

confidence: 99%

Determination of atomic scattering lengths from measurements of molecular binding energies near Feshbach resonances

et al. 2009

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“…In the center-of-mass frame, we restrict to three quantum levels: one for each atomic species in the continuum and another one for the molecular bound state. Similar to [20] the multitude of continuum states is taken into account by the thermal average of the results. We start with a set of nonlinear differential equations for the amplitudes a j (j = 1, 2) and m of the two atomic and the molecular state, respectively:…”

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confidence: 99%

Association of ultracold double-species bosonic molecules

et al. 2008

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We report on the creation of heterospecies bosonic molecules, associated from an ultracold BoseBose mixture of 41 K and 87 Rb, by using a resonantly modulated magnetic field close to two Feshbach resonances. We measure the binding energy of the weakly bound molecular states versus the Feshbach field and compare our results to theoretical predictions. We observe the broadening and asymmetry of the association spectrum due to thermal distribution of the atoms, and a frequency shift occurring when the binding energy depends nonlinearly on the Feshbach field. A simple model is developed to quantitatively describe the association process. Our work marks an important step forward in the experimental route towards Bose-Einstein condensates of dipolar molecules.PACS numbers: 34.20. Cf, Ultracold polar molecules hold the promise of a revolution in the domain of quantum degenerate gases and precision measurements. Degenerate molecules are sought primarily to produce a gas with strong long-range interactions, stemming from the coupling of electric dipole moments that heterospecies dimers feature. Such molecules would create strongly correlated systems with a wealth of quantum phases [1], provide candidate qubits [2,3], allow for a new generation of dipolar Bose-Einstein condensates (BECs) [4], and help in the search of the electron dipole moment [5]. Starting from ultracold atoms, molecules have been successfully created following two different approaches: photoassociation [6] and magnetoassociation [7], but few experiments have hitherto reported the production of Feshbach heteronuclear dimers. Two groups have reported the creation of fermionic KRb molecules [8,9], while the only bosonic dimer so far associated is 85 Rb 87 Rb [10], which can not be dipolar since the constituents share the same electronic configuration. Heterospecies bosonic dimers, i.e., the constituents of the dipolar BEC envisioned in Ref. [4], have instead eluded experimental realization so far.A Bose-Bose mixture is particularly suitable to associate such dimers due to the high phase-space densities achievable, while the atom-dimer relaxation, which limits the lifetime of the molecules, can be strongly suppressed in optical lattices with a single atom pair per lattice site [11]. Recent progresses in molecular stabilization schemes [12] make the Bose-Bose 41 K 87 Rb mixture truly promising for the experimental observation of BECs of dipolar molecules. Following a different route, other experiments have very recently obtained ultracold heterospecies Fermi-Fermi mixtures [13,14] that also can provide a way to compound bosonic dimers.In this Letter, we report on the production of heterospecies 41 K 87 Rb bosonic molecules starting from an ultracold mixture. In proximity of Feshbach resonances (FR's) at moderate magnetic fields, by adding a modulation to the Feshbach field [15], we have converted up to 12 000 41 K 87 Rb pairs into dimers, i.e., 40% of the minority 41 K atoms, at temperatures between 200 and 600 nK. We estimate the molecular lifetime to be a...

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“…We can obtain the intrinsic frequency in the mean-field limit,i.e., N → ∞. From the mean-field equations (18)(19)(20) we readily obtain,…”

Section: Introductionmentioning

confidence: 99%

“…The many experimental observations can not be accounted for by the existing theoretical model. For example, the Poisson distribution predicted by theory [20] is departure from the observed Lorentzian-like resonance profiles and how the finitetemperature effect influences the resonance profiles is still an open problem. In the present paper, we exploit a microscopic two-channel model to investigate thoroughly the mechanism underlying the Shapiro resonance phenomenon in the atom-molecule conversion.…”

Section: Introductionmentioning

confidence: 99%

Shapiro-like resonance in ultracold molecule production via an oscillating magnetic field

Liu

2010

Phys. Rev. A

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We study the process of production of ultracold molecules from ultracold atoms using a sinusoidally oscillating magnetic field modulation. When the magnetic field is resonant roughly with the molecular binding energy, Shapiro-like resonances are observed. Their resonance profiles are well fitted by the Lorentzian functions. The line widths depend on both the amplitude and the duration of the applied modulations, and are found to be dramatically broadened by thermal dephasing effect. The resonance centers shift due to both many-body effect and finite temperature effect. Our theory is consistent with recent experiment (S. T. Thompson, E. Hodby, and C. E. Wieman, Phys. Rev. Lett. 95, 190404 (2005)). Our model predicts a 1/3 ceiling for the molecular production yield in uncondensed ultracold atomic clouds for a long coupling time, while for the condensed atoms the optimal conversion yield could be beyond the limit.

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Association of molecules using a resonantly modulated magnetic field

Cited by 41 publications

References 38 publications

Determination of atomic scattering lengths from measurements of molecular binding energies near Feshbach resonances

Determination of atomic scattering lengths from measurements of molecular binding energies near Feshbach resonances

Association of ultracold double-species bosonic molecules

Shapiro-like resonance in ultracold molecule production via an oscillating magnetic field

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