Collisional dynamics of symmetric two-dimensional quantum droplets

TL;DR

This paper investigates the collision dynamics of symmetric two-dimensional quantum droplets, revealing oscillation behaviors, separation thresholds, and stability conditions through extended Gross-Pitaevskii simulations.

Contribution

It introduces a detailed analysis of droplet collisions including shape oscillations, separation criteria, and stability peaks, with a focus on the effects of logarithmic corrections in the interaction.

Findings

Quadrupole oscillation period is independent of incident momentum for small droplets.

Droplets can separate into multiple fragments at higher collision energies.

A stability peak at N_c ≈ 48 indicates the critical particle number for droplet existence.

Abstract

The collisional dynamics of two symmetric droplets with equal intraspecies scattering lengths and particle number density for each component is studied by solving the corresponding extended Gross-Pitaevskii equation in two dimensions by including a logarithmic correction term in the usual contact interaction. We find the merging droplet after collision experiences a quadrupole oscillation in its shape and the oscillation period is found to be independent of the incidental momentum for small droplets. With increasing collision momentum the colliding droplets may separate into two, or even more, and finally into small pieces of droplets. For these dynamical phases, we manage to present boundaries determined by the remnant particle number in the central area and the damped oscillation of the quadrupole mode. A stability peak for the existence of droplets emerges at the critical particle number $N_c \simeq 48$ for the quasi-Gaussian and flat-top shapes of the droplets.