Droplet-gas phases and their dynamical formation in particle imbalanced mixtures

TL;DR

This paper investigates the phase diagram and dynamics of two-component particle-imbalanced droplets in 3D confinements, revealing transitions between mixed droplet-gas and gas states, supported by numerical and variational methods, with experimental relevance.

Contribution

It introduces a detailed analysis of droplet-gas phases in imbalanced mixtures, combining numerical simulations and variational approaches, and demonstrates experimental techniques to identify these phases.

Findings

Transition from mixed droplet-gas to gas with decreasing attraction or tighter confinement.

Majority fragments bind to minority droplets, satisfying density ratio locking.

Experimental simulations show the resilience and expansion of droplet and gas phases.

Abstract

We explore the ground state phase diagram and nonequilibrium dynamics of genuine two-component particle-imbalanced droplets in both isotropic and anisotropic three-dimensional confinements. A gradual transition from mixed droplet-gas to gas configurations is revealed as the average intercomponent attraction decreases or the transverse confinement becomes tighter. Within the mixed structures, a specific majority fragment binds to the minority droplet, satisfying the density ratio locking condition, while the remaining atoms are in a gas state. Our extended Gross-Pitaevskii numerical results are corroborated by a suitable variational approximation capturing the shape and characteristics of droplet-gas fragments. The tunability of the relatively low gas fraction is showcased through parametric variations of the atom number, the intercomponent imbalance, the trap aspect ratio, or the radius of a box potential. To validate the existence and probe the properties of these exotic phases, we simulate the standard time-of-flight and radio frequency experimental techniques. These allow to dynamically identify the resilience of the droplet fragment and the expansion of the gas fraction. Our results, amenable to current experimental cold atom settings, are expected to guide forthcoming investigations aiming to reveal unseen out-of-equilibrium droplet dynamics.