Three-body recombination of two-component cold atomic gases into deep dimers in an optical model

Abstract

We consider three-body recombination into deep dimers in a mass-imbalanced two-component atomic gas. We use an optical model where a phenomenological imaginary potential is added to the lowest adiabatic hyper-spherical potential. The consequent imaginary part of the energy eigenvalue corresponds to the decay rate or recombination probability of the three-body system. The method is formulated in details and the relevant qualitative features are discussed as functions of scattering lengths and masses. We use zero-range model in analyses of recent recombination data. The dominating scattering length is usually related to the non-equal two-body systems. We account for temperature smearing which tends to wipe out the higher-lying Efimov peaks. The range and the strength of the imaginary potential determine positions and shapes of the Efimov peaks as well as the absolute value of the recombination rate. The Efimov scaling between recombination peaks is calculated and shown to depend on both scattering lengths. Recombination is predicted to be largest for heavy-heavy-light systems. Universal properties of the optical parameters are indicated. We compare to available experiments and find in general very satisfactory agreement.

Universal few-body physics and cluster formation

“…The existence of an infinite series of three-body bound states for resonant two-body interaction, as predicted by Efimov (Efimov, 1970), is not only present for homonuclear systems, as such universal three-body bound states should appear as well for heteronuclear systems (D'Incao and Esry, 2006a,b;Efimov, 1973aEfimov, , 1979Helfrich et al, 2010;Mikkelsen et al, 2015;Petrov and Werner, 2015;Wang et al, 2012dWang et al, , 2015b. In particular, in heteronuclear systems the mass-imbalanced nature of the threebody system preserves but modifies in an interesting way the discrete symmetry scaling characteristic of Efimov Figure 10 (Color online) (a)Schematic hyperspherical potential curve relevant to five-boson recombination when the twobody scattering length is negative, a < 0.…”

Heteronuclear Efimov Scenario with Positive Intraspecies Scattering Length

“…The resonance positions cannot be directly fitted from the experimental loss-rate data, since the excited resonance features are all already located into the unitarity limited regime, and, thus, effects of finite temperature would have to be included (for negative intraspecies scattering length, see Refs. [14,43,44]). Therefore, encouraged by the good agreement between the experimental findings and the vdW model, we extract Efimov resonance positions a (n) −,CsLi from the calculated trimer energy spectra as the average value of the two numerical grid points, between which the three-body states merge with the scattering continuum (see Fig.…”

Universal Three-Body Physics in Ultracold KRb Mixtures

“…In the following we compare our three-body recombination results with our theoretical model and with results obtained in 41 K-87 Rb and 40 K-87 Rb [28,29,31,53]. For negative scattering lengths, our theoretical framework [26] is applied, assuming no Efimov resonances as shown in Fig. 2 and 3.…”

“…Mass-imbalanced systems can provide a much denser spectrum when all scattering lenghs are large [26,27]. So far only four different heteronuclear isotopic mixtures have been investigated.…”