Controlling the Scattering Length of Ultracold Dipolar Molecules

• Published in: Physical review letters 2018-10, Vol.121 (16), p.163402-163402, Article 163402
• Main Authors: Lassablière, Lucas, Quéméner, Goulven
• Format: Article
• Language: English
• Subjects: Atomic Physics; Circular polarization; Condensed Matter; Entrances; Physics; Quantum Gases; Quantum Physics; Quenching; Rotational states; Scattering; Stability
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.121.163402

By applying a circularly polarized and slightly blue-detuned microwave field with respect to the first excited rotational state of a dipolar molecule, one can engineer a long-range, shallow potential well in the entrance channel of the two colliding partners. As the applied microwave ac field is increased, the long-range well becomes deeper and can support a certain number of bound states, which in turn bring the value of the molecule-molecule scattering length from a large negative value to a large positive one. We adopt an adimensional approach where the molecules are described by a rescaled rotational constant B[over ˜]=B/s_{E_{3}} where s_{E_{3}} is a characteristic dipolar energy. We found that molecules with B[over ˜]>10^{8} are immune to any quenching losses when a sufficient ac field is applied, the ratio elastic to quenching processes can reach values above 10^{3}, and that the value and sign of the scattering length can be tuned. The ability to control the molecular scattering length opens the door for a rich, strongly correlated, many-body physics for ultracold molecules, similar to that for ultracold atoms.