Miscibility Regimes in a 23Na-39K Quantum Mixture

The effects of miscibility in interacting two-component classical fluids are relevant in a broad range of daily applications. When considering quantum systems, two-component Bose-Einstein condensates provide a well-controlled platform where the miscible-immiscible phase transition can be completely characterized. In homogeneous systems, this phase transition is governed only by the competition between intra- and inter-species interactions. However, in more conventional experiments dealing with trapped gases, the pressure of the confinement increases the role of the kinetic energy and makes the system more miscible. In the most general case, the miscibility phase diagram of unbalanced mixtures of different atomic species is strongly modified by the atom number ratio and the different gravitational sags. Here, we numerically investigate the ground-state of a 23Na-39K quantum mixture for different interaction strengths and atom number ratios considering realistic experimental parameters. Defining the spatial overlap between the resulting atomic clouds, we construct the phase diagram of the miscibility transition which could be directly measured in real experiments.

Automated summary

The study focuses on the miscibility effects of two-component classical fluids and the miscible-immiscible phase transition in two-component Bose-Einstein condensates. In homogeneous systems, the phase transition is governed by the competition between intra- and inter-species interactions. Conventional experiments with trapped gases show increased miscibility due to the pressure of confinement. The miscibility phase diagram of unbalanced mixtures of different atomic species is strongly influenced by the atom number ratio and gravitational sags.