Miscibility and stability of dipolar bosonic mixtures

TL;DR

This paper investigates the complex behaviors of dipolar two-component Bose-Einstein condensates, revealing how dipolar interactions influence miscibility, stability, and phase transitions depending on dipole orientation and confinement geometry.

Contribution

It provides a comprehensive theoretical analysis of how dipolar interactions affect the miscibility and stability of two-component BECs, including phase transition mechanisms.

Findings

Dipolar interactions can significantly alter stability and miscibility.

Equivalent dipoles have minimal impact on immiscibility transition.

Antiparallel dipoles strongly influence miscibility but not stability.

Abstract

Combining two Bose-Einstein condensates (BECs) may result in a miscible or immiscible mixture, or even a violent implosion. We theoretically demonstrate that dipolar two-component BECs produce far richer physics than their nondipolar counterparts. Intriguingly, when both components have equivalent dipoles, the transition to immiscibility is largely unaffected by dipolar physics, yet the dipoles maximally affect stability. Conversely, antiparallel dipoles strongly affect miscibility but have little effect on stability. By performing three-dimensional calculations of the ground states and their excitations, we find strong dependencies on the confinement geometry. We explore and elucidate the various phononic and rotonic phase transitions, as well as symmetry preserving crossovers.