Universal Scattering of Ultracold Atoms and Molecules in Optical Potentials

Li, Hui; Li, Ming; Makrides, Constantinos; Petrov, A. N.; Kotochigova, Svetlana

doi:10.3390/atoms7010036

Cited by 15 publications

(20 citation statements)

References 43 publications

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“…2(b). This value agrees with the predicted universal loss rate for s-wave collisions between KRb and Rb, k m,a = 7.0 × 10 −11 cm 3 s −1 [43], indicating that atoms and molecules which reach the short-range part of the interaction potential are lost with unit probability.…”

supporting

confidence: 87%

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Detection of Long-Lived Complexes in Ultracold Atom-Molecule Collisions

Nichols¹,

Liu²,

Zhu³

et al. 2021

Preprint

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We investigate collisional loss in an ultracold mixture of 40 K 87 Rb molecules and 87 Rb atoms, where chemical reactions between the two species are energetically forbidden. Through direct detection of the KRb * 2 intermediate complexes formed from atom-molecule collisions, we show that a 1064 nm laser source used for optical trapping of the sample can efficiently deplete the complex population via photo-excitation, an effect which can explain the universal two-body loss observed in the mixture. By monitoring the time-evolution of the KRb * 2 population after a sudden reduction in the 1064 nm laser intensity, we measure the lifetime of the complex (0.39(6) ms), as well as the photo-excitation rate for 1064 nm light (0.50(3) µs −1 (kW/cm 2 ) −1 ). The observed lifetime is ∼10 5 times longer than recent estimates based on the Rice-Ramsperger-Kassel-Marcus statistical theory, which calls for new insight to explain such a dramatic discrepancy.

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supporting

confidence: 87%

“…(b) Dependence of the molecular loss rate on the atomic density. A linear fit (black solid line) yields km,a = 6.8(7) × 10 −11 cm 3 s −1 , which is consistent with the predicted universal loss rate[43]. All data shown in (a) and (b) are taken with B = 542 G in a continuously operated ODT of intensity Itot = 11.3 kW/cm 2 .…”

supporting

confidence: 78%

Detection of Long-Lived Complexes in Ultracold Atom-Molecule Collisions

Nichols¹,

Liu²,

Zhu³

et al. 2021

Preprint

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“…As a final comment, considering the different possibilities to study few-body physics in atomic traps, we should mention that few-atom system can also be driven by the change in the effective dimensions, by squeezing the trap, while tuning both the two and few-body parameters controlling the Feshbach resonance. Controlled cold chemical reactions [60][61][62] with forces driven by external fields is also a field of intense activity (see, e.g., [63][64][65][66][67][68][69][70]).…”

Section: Final Considerationsmentioning

confidence: 99%

“…Controlled cold chemical reactions [60][61][62] with forces driven by external fields is also a field of intense activity (see e.g. [63][64][65][66][67][68][69][70]).…”

Section: Modelmentioning

confidence: 99%

Emergence of N-Body Tunable Interactions in Universal Few-Atom Systems

2020

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A three-atom molecule AAB, formed by two identical bosons A and a distinct one B, is studied by considering coupled channels close to a Feshbach resonance. It is assumed that the subsystems AB and AA have, respectively, one and two channels, where, in this case, AA has open and closed channels separated by an energy gap. The induced three-body interaction appearing in the single channel description is derived using the Feshbach projection operators for the open and closed channels. An effective three-body interaction is revealed in the limit where the trap setup is tuned to vanishing scattering lengths. The corresponding homogeneous coupled Faddeev integral equations are derived in the unitarity limit. The s-wave transition matrix for the AA subsystem is obtained with a zero-range potential by a subtractive renormalization scheme with the introduction of two finite parameters, besides the energy gap. The effect of the coupling between the channels in the coupled equations is identified with the energy gap, which essentially provides an ultraviolet scale that competes with the van der Waals radius-this sets the short-range physics of the system in the open channel. The competition occurring at short distances exemplifies the violation of the "van der Waals universality" for narrow Feshbach resonances in cold atomic setups. In this sense, the active role of the energy gap drives the short-range three-body physics.

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“…For more recent experimental activities reported in the last five years, on ultracold atom-dimer collisions, by using tunable Feshbach resonances, we should also mention the Refs. [34][35][36][37][38][39][40][41].…”

Section: Introductionmentioning

confidence: 99%

Cold atom-dimer reaction rates with $^4$He, $^{6,7}$Li and $^{23}$Na

Shalchi,

Yamashita,

Frederico

et al. 2020

Preprint

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Atom-dimer exchange and dissociation reaction rates are predicted for different combinations of two 4 He atoms and one of the alkaline species among 6 Li, 7 Li and 23 Na, by using three-body scattering formalism with short-range two-body interactions. Our study was concerned with lowenergy reaction rates in which the s−, p− and d− wave contributions are the relevant ones. The 4 He is chosen as one of the atoms in the binary mixture, in view of previous available investigations and laboratory accessibilities. Focusing on possible experimental cold-atom realizations with twoatomic mixtures, in which information on atom-dimer reaction rates can be extracted, we predict the occurrence of a dip in the elastic reaction rate for colliding energies smaller than 20 mK, when the dimer is the 4 He 23 Na molecule. We are also anticipating a zero in the elastic p−wave contribution for the 4 He + 4 He 7 Li and 4 He + 4 He 23 Na reaction processes. With weakly-bound molecules reacting with atoms at very low colliding energies, we interpret our results on the light of Efimov physics which supports model independence and robustness of our predictions. Specific sensitivities on the effective range were evidenced, highlighted by the particular inversion role of the p− and d−waves in the atom exchange and dissociation processes.

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Universal Scattering of Ultracold Atoms and Molecules in Optical Potentials

Cited by 15 publications

References 43 publications

Detection of Long-Lived Complexes in Ultracold Atom-Molecule Collisions

Detection of Long-Lived Complexes in Ultracold Atom-Molecule Collisions

Emergence of N-Body Tunable Interactions in Universal Few-Atom Systems

Cold atom-dimer reaction rates with $^4$He, $^{6,7}$Li and $^{23}$Na

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