Quantum antidipolar systems in two-dimensional geometries

Particles with magnetic moment can be polarized, and rapidly rotated, employing a magnetic field such that the dipolar interaction among them changes sign, becoming antidipolar and thus isotropically attractive in a plane. Polar molecules can also be manipulated using microwave dressing fields to invert the sign of the dipole-dipole interaction. In this work, we study a two-dimensional system of antidipolar particles by calculating its equation of state and structural properties. The system behaves as a liquid even for scattering lengths significantly greater than the dipolar length. For large enough densities, the system transitions to a solid with one particle per lattice site via a first-order phase transition at a significantly smaller density than its dipolar counterpart. Moreover, motivated by the recent realization of a strongly axially trapped, bilayer geometry [Science 384, 546-551 (2024)], we study the properties of the bilayer liquid phase as the inter-layer distance is tuned, and provide the range of parameters where one layer can influence the properties of the other.