Dynamics of equilibration and collisions in ultradilute quantum droplets

Employing time-dependent density-functional theory, we have studied dynamical equilibration and binary head-on collisions of quantum droplets taking as a case of study droplets made of a K-39 - K-39 Bose mixture. The phase space of collision outcomes is extensively explored by performing fully three-dimensional calculations with effective single-component Quantum Monte Carlo-based and two-component LHY-corrected mean-field functionals. We exhaustively explored the important effect-not considered in previous studies-of the initial population ratio deviating from the optimal mean-field value N-2/N-1 = root a(11)/a(22). Both stationary and dynamical calculations indicate sensitivity to an initial nonoptimal concentration. When three-body losses (3BL) are present our two-component approach allows to theoretically address situations in which they mainly act on one of the components of the mixture. Our approach also allows to simultaneously explore the effect on the simulation of population imbalance and 3BL, which are coupled when they act.

Automated summary

This study investigates the dynamical equilibration and binary head-on collisions of quantum droplets made of a K-39 - K-39 Bose mixture using time-dependent density-functional theory. Important effects of initial population ratio deviation from the optimal mean-field value are extensively explored. The study shows sensitivity to an initial nonoptimal concentration and proposes a two-component approach for addressing situations with three-body losses mainly acting on one of the mixture's components.