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Cai-Yun Zhao

Publications and source records attributed to Cai-Yun Zhao.

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Effects of $p$-wave Interactions on Borromean Efimov Trimers in Heavy-Light Fermi Systems

We investigate the effects of $p$-wave interactions on Efimov trimers in systems comprising two identical heavy fermions and a light particle, with mass ratios larger than $13.6$. Our focus lies on the borromean regime where the ground-state trimer exists in the absence of dimers. Using pair-wise Lennard-Jones potentials and concentrating on the $L^π = 1^{-}$ symmetry, we explore the critical value of the interspecies $s$-wave scattering length $a_{c}$ at which the borromean state appears in several two-component particle systems. Our exploration encompasses the universal properties of $a_{c}$ and the influence of $p$-wave fermion-fermion interactions on its value. We find that, in the absence of $p$-wave fermion-fermion interactions, $a_{c}$ is determined universally by the van der Waals radius and mass ratio. However, the introduction of $p$-wave fermion-fermion interactions unveiled a departure from this universality. Our calculations show that the critical interspecies scattering length $a_{c}$ now depends on the details of the fermion-fermion $p$-wave interaction. And, the presence of $p$-wave fermion-fermion interactions favors the formation of the borromean state. Additionally, our investigation reveals that Efimov effect in the $1^{-}$ symmetry persist even when the fermion-fermion interaction reaches the $p$-wave unitary limit.

physics.atom-ph

Hyperspherical approach to atom--dimer collision with the Jacobi boundary condition

In this study, we investigate atom--dimer scattering within the framework of the hyperspherical method. The coupled channel Schrödinger equation is solved using the R-matrix propagation technique combined with the smooth variable discretization method. In the matching procedure, the asymptotic wave functions are expressed in the rotated Jacobi coordinates. We apply this approach to the elastic scattering $^{3}$He(T$\uparrow$) + $^{4}$He$_{2}$ and H$\uparrow$ + H$\uparrow$Li processes. The convergence of the scattering length as a function of the propagation distance is studied. We find that the method is reliable and can provide considerable savings over previous propagators.

physics.atom-ph

Three-body recombination near the d-wave resonance in ultracold $^{85}$Rb\,-$^{87}$Rb mixtures

We have studied the three-body recombination rates on both sides of the interspecies d-wave Feshbach resonance in the $^{85}$Rb\,-$^{87}$Rb-$^{87}$Rb system using the $R$-matrix propagation method in the hyperspherical coordinate frame. Two different mechanisms of recombination rate enhancement for positive and negative $^{85}$Rb\,-$^{87}$Rb d-wave scattering lengths are analyzed. On the positive scattering length side, the recombination rate enhancement occurs due to the existence of three-body shape resonance, while on the negative scattering length side, the coupling between the lowest entrance channel and the highest recombination channel is crucial to the appearance of the enhancement. In addition, our study shows that the intraspecies interaction plays a significant role in determining the emergence of recombination rate enhancements. Compared to the case in which the three pairwise interactions are all in d-wave resonance, when the $^{87}$Rb-$^{87}$Rb interaction is near the d-wave resonance, the values of the interspecies scattering length that produce the recombination enhancement shift. In particular, when the $^{87}$Rb-$^{87}$Rb interaction is away from the d-wave resonance, the enhancement disappears on the negative interspecies scattering length side.

cond-mat.quant-gas