Fig. 1: Electroassociation of field-linked tetramers.
a, Microwave-dressed NaK dimers are associated into (NaK)2 tetramers as the microwave polarization is ramped from circular to elliptical. b,c, Interaction potentials between two dimers approaching along the long axis of the microwave field. The potential depth increases with the ellipticity ξ and a tetramer bound state emerges from the collisional threshold. The light orange line shows the radial wavefunction of the tetramer, and the black solid line indicates its binding energy. d, Calculated binding energy of the tetramers. The field-linked resonance (dashed line) marks the onset of the tetramer state. The stars and the arrow mark the electroassociation trajectory in the experiment. Within the range of experimental parameters, there exists only a single field-linked tetramer state (Methods).
