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arXiv · 2012.14008

Quantum phase transition of a two-dimensional quadrupolar system

G. E. Astrakharchik·I. L. Kurbakov·D. V. Sychev·A. K. Fedorov·Yu. E. Lozovik
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Abstract

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

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G. E. Astrakharchik, I. L. Kurbakov, D. V. Sychev, A. K. Fedorov, Yu. E. Lozovik. 2020-12-27. Quantum phase transition of a two-dimensional quadrupolar system. https://doi.org/10.1103/physrevb.103.l140101

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