Ultradilute low-dimensional liquids

TL;DR

This paper analytically and numerically investigates ultradilute low-dimensional Bose-Bose liquids, revealing their liquid state formation due to specific interactions and deriving a governing equation for droplets.

Contribution

It provides the first analytical and numerical analysis of ultradilute low-dimensional Bose-Bose liquids, including a derived Gross-Pitaevskii equation for droplets.

Findings

Energy per particle has a minimum at finite density indicating a liquid state.

Analytical solutions for droplets in one-dimensional systems.

Validation of results using diffusion Monte Carlo simulations.

Abstract

We calculate the energy of one- and two-dimensional weakly interacting Bose-Bose mixtures analytically in the Bogoliubov approximation and by using the diffusion Monte Carlo technique. We show that in the case of attractive inter- and repulsive intraspecies interactions the energy per particle has a minimum at a finite density corresponding to a liquid state. We derive the Gross-Pitaevskii equation to describe droplets of such liquids and solve it analytically in the one-dimensional case.