From Microwave Shielding to Field-Linked Resonances

Very recently two types of resonances were found that allow to tune the contact interaction of dipolar molecules and open up the possibility to form ultracold tetramer molecules. While the Ketterle group observed Feshbach resonances of triplet ground-state molecules at MIT [1], I report here about so-called field-linked resonances of singlet ground-state molecules [2]. Field-linked resonances had already been predicted 20 years ago by John Bohn's group [3]. We* now realized them by shaping the long-range intermolecular potential that is induced by a microwave field for microwave shielding [4-7]. By tuning the parameters of the microwave field (polarization, intensity, and detuning from the rotational transition) we can engineer a potential well that is deep enough to house field-linked bound-states, which give rise to the resonances. The coexistence of large dipole-dipole interaction and tunable contact interaction in the vicinity of the field-linked resonances enables the investigation of novel kinds of dipolar superfluids and supersolids.



* Collaborators: Xing-Yan Chen, Sebastian Eppelt, Roman Bause, Marcel Duda, Shrestha Biswas, Tijs Karman, Timon Hilker, Immanuel Bloch, and Xin-Yu Luo

[1] J. J. Park et al., Nature 614, 54 (2023) [2] X.-Y. Chen et al., Nature 614, 59 (2023) [3] A. V. Avdeenkov et al., Phys. Rev. Lett. 90, 043006 (2003) [4] T. Karman et al., Phys. Rev. Lett. 121, 163401 (2018) [5] L. Lassablière et al., Phys. Rev. Lett. 121, 163402 (2018) [6] L. Anderegg et al., Science 373, 779 (2021) [7] A. Schindewolf et al., Nature 607, 677 (2022)