85Rb BEC near a Feshbach resonance

We precisely measured the binding energy $({\ensuremath{\epsilon}}_{\mathrm{bind}})$ of a molecular state near the Feshbach resonance in a ${}^{85}\mathrm{Rb}$ Bose-Einstein condensate (BEC). Rapid magnetic-field pulses induced coherent atom-molecule oscillations in the BEC. We measured the oscillation frequency as a function of B field and fit the data to a coupled-channel model. Our analysis constrained the Feshbach resonance position [155.041(18) G], width [10.71(2) G], and background scattering length $[\ensuremath{-}{443(3)a}_{0}]$ and yielded new values for the Rb interaction parameters. These results improved our estimate for the stability condition of an attractive BEC. We also found evidence for a mean-field shift to ${\ensuremath{\epsilon}}_{\mathrm{bind}}.$We precisely measured the binding energy $({\ensuremath{\epsilon}}_{\mathrm{bind}})$ of a molecular state near the Feshbach resonance in a ${}^{85}\mathrm{Rb}$ Bose-Einstein condensate (BEC). Rapid magnetic-field pulses induced coherent atom-molecule oscillations in the BEC. We measured the oscillation frequency as a function of B field and fit the data to a coupled-channel model. Our analysis constrained the Feshbach resonance position [155.041(18) G], width [10.71(2) G], and background scattering length $[\ensuremath{-}{443(3)a}_{0}]$ and yielded new values for the Rb interaction parameters. These results improved our estimate for the stability condition of an attractive BEC. We also found evidence for a mean-field shift to ${\ensuremath{\epsilon}}_{\mathrm{bind}}.$

arXiv:cond-mat/0302195Physical Review AJun 20, 2003146 citations

Tuning atomic interactions near a Feshbach resonance in 87Rb

R. L. Compton, Yu‐Ju Lin, Karina Jiminez-Garcia +1 more

Bulletin of the American Physical SocietyMay 22, 20090 citations

Feshbach Resonance

Peking University-World Scientific advanced physics series/Peking University-World Scientific advance physics seriesNov 1, 20180 citations

Breakdown of Kohn Theorem Near Feshbach Resonance

Hamid Al-Jibbouri, Axel Pelster

We study the collective excitation frequencies of a harmonically trapped 85Rb Bose-Einstein condensate (BEC) in the vicinity of a Feshbach resonance. To this end, we solve the underlying Gross-Pitaevskii (GP) equation by using a Gaussian variational approach and obtain the coupled set of ordinary differential equations for the widths and the center of mass of the condensate. A linearization shows that the dipole mode frequency decreases when the bias magnetic field approaches the Feshbach resonance, so the Kohn theorem is violated.We study the collective excitation frequencies of a harmonically trapped 85Rb Bose-Einstein condensate (BEC) in the vicinity of a Feshbach resonance. To this end, we solve the underlying Gross-Pitaevskii (GP) equation by using a Gaussian variational approach and obtain the coupled set of ordinary differential equations for the widths and the center of mass of the condensate. A linearization shows that the dipole mode frequency decreases when the bias magnetic field approaches the Feshbach resonance, so the Kohn theorem is violated.

arXiv:1306.1988Jun 9, 20131 citation

[sup 85]Rb BEC near a Feshback resonance

N. R. Claussen

Bose-Einstein condensation has been achieved in a magnetically trapped sample of 85Rb atoms. Stable condensates of up to 104 atoms have been created by using a magnetic-field-induced Feshbach resonance to reverse the sign of the zero-field scattering length. These condensates provide unique opportunities for the study of BEC physics. The variation of the scattering length near the resonance has been used to magnetically tune the condensate self-interaction energy over a very wide range. This range extended from very strong repulsive self-interactions to large attractive ones. The effect of moving the condensate through the Feshbach resonance has been studied and compared with theory. Long-lived metastable condensates with attractive interactions have been produced near the zero of the Feshbach resonance. The transition from repulsive to attractive interactions can lead to a “collapse” of the condensate in which the cloud shrinks below our resolution limit, loses a significant number of atoms due to inelastic losses, and emits a burst of high-energy atoms.Bose-Einstein condensation has been achieved in a magnetically trapped sample of 85Rb atoms. Stable condensates of up to 104 atoms have been created by using a magnetic-field-induced Feshbach resonance to reverse the sign of the zero-field scattering length. These condensates provide unique opportunities for the study of BEC physics. The variation of the scattering length near the resonance has been used to magnetically tune the condensate self-interaction energy over a very wide range. This range extended from very strong repulsive self-interactions to large attractive ones. The effect of moving the condensate through the Feshbach resonance has been studied and compared with theory. Long-lived metastable condensates with attractive interactions have been produced near the zero of the Feshbach resonance. The transition from repulsive to attractive interactions can lead to a “collapse” of the condensate in which the cloud shrinks below our resolution limit, loses a significant number of atoms due to inelastic losses, and emits a burst of high-energy atoms.

AIP conference proceedingsJan 1, 20010 citations

We precisely measured the binding energy $({\ensuremath{\epsilon}}_{\mathrm{bind}})$ of a molecular state near the Feshbach resonance in a

{}^{85}\mathrm{Rb}

Bose-Einstein condensate (BEC). Rapid magnetic-field pulses induced coherent atom-molecule oscillations in the BEC. We measured the oscillation frequency as a function of B field and fit the data to a coupled-channel model. Our analysis constrained the Feshbach resonance position [155.041(18) G], width [10.71(2) G], and background scattering length $[\ensuremath{-}{443(3)a}_{0}]$ and yielded new values for the Rb interaction parameters. These results improved our estimate for the stability condition of an attractive BEC. We also found evidence for a mean-field shift to ${\ensuremath{\epsilon}}_{\mathrm{bind}}.$