Creating and exploring Bose-Einstein condensates of dipolar molecules

Sebastian Will Columbia University

The creation of Bose-Einstein condensates (BECs) of dipolar molecules has been a long- standing goal in ultracold quantum science. Already soon after the first atomic BECs, it was understood that molecular quantum systems with dipole-dipole interactions would open up novel opportunities for many-body quantum physics. But cooling of molecules to sufficiently low temperatures proved to be exceedingly hard due to strong collisional losses in molecular gases.

Recently, we have created the first BECs of dipolar molecules [1-3]. We evaporatively cool sodium- cesium molecules to below 10 nanokelvin, deep in the quantum degenerate regime. The BECs live for several seconds, reaching a level of stability similar to ultracold atomic gases. This dramatic improvement over previous attempts to cool molecular gases is enabled by collisional shielding via microwave fields, suppressing inelastic losses by four orders of magnitude. The creation of a BEC constitutes the first observation of a phase transition in an ultracold molecular gas. In this talk, I will discuss our experimental approach, share latest insights, and give an outlook on novel opportunities for many-body quantum physics, quantum simulation, and quantum computing.

[1] Bigagli, Yuan, Zhang, et al., Observation of Bose-Einstein condensation of dipolar molecules, Nature 631, 289-293 (2024)

[2] Bigagli, et al., Collisionally stable gas of bosonic dipolar ground state molecules, Nature Physics 19, 1579-1584 (2023)

[3] Stevenson, et al., Ultracold gas of dipolar NaCs ground state molecules, Phys. Rev. Lett. 130, 113003 (2023)