Phase separation of Bose-Einstein condensates

TL;DR

This paper investigates the conditions under which two overlapping Bose-Einstein condensates undergo phase separation, analyzing stability, boundary properties, and implications for trapped atomic systems.

Contribution

It provides a theoretical analysis of phase separation criteria and properties in two-component Bose-Einstein condensates at zero temperature.

Findings

Instability occurs when interspecies interaction exceeds geometric mean of intraspecies interactions.

Repulsive interactions lead to spatial separation of condensates.

Estimated boundary size, surface tension, and energy of phase-separated states.

Abstract

The zero-temperature system of two dilute overlapping Bose-Einstein condensates is unstable against long wavelength excitations if the interaction strength between the distinguishable bosons exceeds the geometric mean of the like-boson interaction strengths. If the condensates attract each other, the instability is similar to the instability of the negative scattering length condensates. If the condensates repel, they separate spatially into condensates of equal pressure. We estimate the boundary size, surface tension and energy of the phase separated condensate system and we discuss the implications for double condensates in atomic traps.