The investigation of ultracold atomic or molecular collision is important for us to understand the essence of a chemical reaction. We present a simple analytical model of arbitrary-order partial-wave scatterings for ultracold molecular collision in the threshold regime. The threshold formulas of the transmission and reflection coefficients are given. For high-partial-wave collision, shape resonance will take place because of the existence of a centrifugal barrier. We investigate the effect of shape resonance and short-range interaction on molecular collisions. Moreover, we find a method to fit the loss parameter from the experimental data of ultracold bosonic molecular collision. As an applied example, we calculate the thermally average loss rate for the ultracold $^{87}\mathrm{Rb}\phantom{\rule{0.16em}{0ex}}^{133}\mathrm{Cs}+^{87}\mathrm{Rb}\phantom{\rule{0.16em}{0ex}}^{133}\mathrm{Cs}$ collision, our results are consistent with the recent experimental and theoretical results of Gregory et al. [Nat. Commun. 10, 3104 (2019)].The investigation of ultracold atomic or molecular collision is important for us to understand the essence of a chemical reaction. We present a simple analytical model of arbitrary-order partial-wave scatterings for ultracold molecular collision in the threshold regime. The threshold formulas of the transmission and reflection coefficients are given. For high-partial-wave collision, shape resonance will take place because of the existence of a centrifugal barrier. We investigate the effect of shape resonance and short-range interaction on molecular collisions. Moreover, we find a method to fit the loss parameter from the experimental data of ultracold bosonic molecular collision. As an applied example, we calculate the thermally average loss rate for the ultracold $^{87}\mathrm{Rb}\phantom{\rule{0.16em}{0ex}}^{133}\mathrm{Cs}+^{87}\mathrm{Rb}\phantom{\rule{0.16em}{0ex}}^{133}\mathrm{Cs}$ collision, our results are consistent with the recent experimental and theoretical results of Gregory et al. [Nat. Commun. 10, 3104 (2019)].

Physical Review AJun 2, 20206 citations

Model for investigating quantum reflection and quantum coherence in ultracold molecular collisions

Yan-Peng Bai, Jing-Lun Li, Gao‐Ren Wang +1 more

We present a simple model used for investigating the quantum reflection and quantum coherence in ultracold molecular collisions. Analytical expressions of reflection and transmission coefficients, short-range $S$ matrix, and transition matrix $T$ are derived for the hard-core plus inverse power potentials in the vicinity of the threshold. The effect of the quantum reflection and coherence on the loss rate depends on the scattering length and short-range loss parameter. The quantum coherence results from the phase difference $\ensuremath{\theta}$ between reflection paths. As an applied example, we calculate the loss rate of $^{23}\mathrm{Na}^{87}\mathrm{Rb}$ molecules in the ultracold $^{23}\mathrm{Na}^{87}\mathrm{Rb}\ensuremath{-}^{23}\mathrm{Na}^{87}\mathrm{Rb}$ collision. We can well interpret the experimental results of the ultracold $^{23}\mathrm{Na}^{87}\mathrm{Rb}$ molecular collision [Ye et al., Sci. Adv. 4, eaaq0083 (2018)]. It is found that the quantum coherence has a significant influence on the loss rate of $^{23}\mathrm{Na}^{87}\mathrm{Rb}$ molecules in ultracold molecule-molecule collisions.We present a simple model used for investigating the quantum reflection and quantum coherence in ultracold molecular collisions. Analytical expressions of reflection and transmission coefficients, short-range $S$ matrix, and transition matrix $T$ are derived for the hard-core plus inverse power potentials in the vicinity of the threshold. The effect of the quantum reflection and coherence on the loss rate depends on the scattering length and short-range loss parameter. The quantum coherence results from the phase difference $\ensuremath{\theta}$ between reflection paths. As an applied example, we calculate the loss rate of $^{23}\mathrm{Na}^{87}\mathrm{Rb}$ molecules in the ultracold $^{23}\mathrm{Na}^{87}\mathrm{Rb}\ensuremath{-}^{23}\mathrm{Na}^{87}\mathrm{Rb}$ collision. We can well interpret the experimental results of the ultracold $^{23}\mathrm{Na}^{87}\mathrm{Rb}$ molecular collision [Ye et al., Sci. Adv. 4, eaaq0083 (2018)]. It is found that the quantum coherence has a significant influence on the loss rate of $^{23}\mathrm{Na}^{87}\mathrm{Rb}$ molecules in ultracold molecule-molecule collisions.

Physical Review AJul 10, 201916 citations

^{87}\mathrm{Rb}\phantom{\rule{0.16em}{0ex}}^{133}\mathrm{Cs}+^{87}\mathrm{Rb}\phantom{\rule{0.16em}{0ex}}^{133}\mathrm{Cs}

collision, our results are consistent with the recent experimental and theoretical results of Gregory et al. [Nat. Commun. 10, 3104 (2019)].

S

matrix, and transition matrix

T

are derived for the hard-core plus inverse power potentials in the vicinity of the threshold. The effect of the quantum reflection and coherence on the loss rate depends on the scattering length and short-range loss parameter. The quantum coherence results from the phase difference $\ensuremath{\theta}$ between reflection paths. As an applied example, we calculate the loss rate of

^{23}\mathrm{Na}^{87}\mathrm{Rb}

molecules in the ultracold $^{23}\mathrm{Na}^{87}\mathrm{Rb}\ensuremath{-}^{23}\mathrm{Na}^{87}\mathrm{Rb}$ collision. We can well interpret the experimental results of the ultracold

^{23}\mathrm{Na}^{87}\mathrm{Rb}

molecular collision [Ye et al., Sci. Adv. 4, eaaq0083 (2018)]. It is found that the quantum coherence has a significant influence on the loss rate of

^{23}\mathrm{Na}^{87}\mathrm{Rb}

molecules in ultracold molecule-molecule collisions.