Quantum phase transition of a two-dimensional quadrupolar system

Ensembles with long-range interactions between particles are promising for revealing strong quantum collective effects and many-body phenomena. Here we study the ground-state phase diagram of a two-dimensional Bose system quadrupolar using diffusion Monte Carlo technique. We predict transition from gas to solid phase. The Lindemann ratio condensate fraction at point $\gamma=0.269(4)$ $n_0/n=0.031(4)$, correspondingly. observe rotonization excitation branch in vicinity point. Our results can be probed state-of-the-art experimental systems various nature, such as quasi-two-dimensional excitons metal dichalcogenide (TMD) trilayers, molecules, or Rydberg atoms quadrupole moments induced by magnetic fields.