Observation of Bose-Einstein Condensation of Dipolar Molecules

TL;DR

This paper reports the first creation of a Bose-Einstein condensate of dipolar molecules, specifically NaCs, achieved by suppressing collisional losses, enabling exploration of novel quantum phases with dipolar interactions.

Contribution

Demonstrated the realization of a stable BEC of dipolar molecules through enhanced collisional shielding, advancing the study of dipolar quantum matter.

Findings

Achieved a BEC of NaCs molecules with 60% condensate fraction.

Reached a temperature of 6 nanokelvin.

Observed a lifetime of nearly 2 seconds for the BEC.

Abstract

Ensembles of particles governed by quantum mechanical laws exhibit fascinating emergent behavior. Atomic quantum gases, liquid helium, and electrons in quantum materials all show distinct properties due to their composition and interactions. Quantum degenerate samples of bosonic dipolar molecules promise the realization of novel phases of matter with tunable dipolar interactions and new avenues for quantum simulation and quantum computation. However, rapid losses, even when reduced through collisional shielding techniques, have so far prevented cooling to a Bose-Einstein condensate (BEC). In this work, we report on the realization of a BEC of dipolar molecules. By strongly suppressing two- and three-body losses via enhanced collisional shielding, we evaporatively cool sodium-cesium (NaCs) molecules to quantum degeneracy. The BEC reveals itself via a bimodal distribution and a phase-space-density exceeding one. BECs with a condensate fraction of 60(10) % and a temperature of 6(2) nK are created and found to be stable with a lifetime close to 2 seconds. This work opens the door to the exploration of dipolar quantum matter in regimes that have been inaccessible so far, promising the creation of exotic dipolar droplets, self-organized crystal phases, and dipolar spin liquids in optical lattices.