Bose-Einstein condensates of microwave-shielded polar molecules

TL;DR

This paper explores the ground-state properties of ultracold bosonic microwave-shielded polar molecules, revealing their stability, phases, and condensate behavior, and challenges the use of traditional equations for such systems.

Contribution

It introduces a variational approach accounting for shielding effects, demonstrating the stability and unique condensate features of microwave-shielded polar molecules.

Findings

The system is always stable with self-bound and expanding phases.

Condensate fraction decreases as shielding core size approaches inter-molecular distance.

Gross-Pitaevskii equation is invalid for these molecular gases.

Abstract

We investigate the ground-state properties of the ultracold gases of bosonic microwave-shielded polar molecules. To account for the large shielding core of the inter-molecular potential, we adopt a variational ansatz incorporating the Jastrow correlation factor. We show that the system is always stable and supports a self-bound gas phase and an expanding gas phase. We also calculate the condensate fraction which is significantly reduced when the size of the shielding core of the two-body potential becomes comparable to the inter-molecular distance. Our studies distinguish the molecular condensates from the atomic ones and invalidate the application of the Gross-Pitaevskii equation to the microwave-shielded molecular gases. Our work paves the way for studying the Bose-Einstein condensations of ultracold gases of microwave-shielded polar molecules.