Dilute quantum liquid in a K-Rb Bose mixture

A quantum liquid in a heterogeneous mixture of K-41 and Rb-87 atoms is studied using the diffusion Monte Carlo method and density-functional theory. The perturbative Lee-Huang-Yang term for a heterogeneous mixture is verified and it is proved to be valid only near the gas-liquid transition. Based on the equations of state of the bulk mixture, calculated with diffusion Monte Carlo, extensions to Lee-Huang-Yang corrected mean-field energy functionals are presented. Using density-functional theory, a systematic comparison between different functionals is performed, focusing on the critical atom number, surface tension, surface width, Tolman length, and compressibility. These results are given as a function of the interspecies interaction strength, within the stability domain of the liquid mixture.

Automated summary

The study focuses on a quantum liquid in a heterogeneous mixture of K-41 and Rb-87 atoms, using diffusion Monte Carlo and density-functional theory to investigate its properties and characteristics. It verifies the perturbative Lee-Huang-Yang term for a heterogeneous mixture and presents extensions to Lee-Huang-Yang corrected mean-field energy functionals based on bulk mixture equations of state calculated with diffusion Monte Carlo. Systematic comparison between different functionals is carried out using density-functional theory, with a focus on critical atom number, surface tension, surface width, Tolman length, and compressibility within the stability domain of the liquid mixture.