In this study, an order-by-disorder mechanism has been proposed in a two-dimensional PXP model, where the extensive degeneracy of the classical ground-state manifold is due to strict occupation constraints instead of geometrical frustrations. By performing an unbias large-scale quantum Monte Carlo simulation, we find that local quantum fluctuations, which usually work against long-range ordering, lift the macroscopic classical degeneracy and give rise to a compressible ground state with charge-density-wave long-range order. A simple trial wave function has been proposed to capture the essence of the ground-state of the two-dimensional PXP model. The finite-temperature properties of this model have also been studied, and we find a thermal phase transition with a universality class of a two-dimensional Ising model.

中文翻译：

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无挫折系统中的无序排序：二维PXP模型的量子蒙特卡洛研究

在这项研究中，在二维PXP模型中提出了一种按序排列的机制，其中经典基态流形的广泛退化是由于严格的职业约束而不是几何上的挫败。通过执行无偏大规模量子蒙特卡洛模拟，我们发现通常对长程有序作用的局部量子涨落会解除宏观经典简并性，并产生带有电荷密度波长程的可压缩基态命令。已经提出了一种简单的试验波函数来捕获二维PXP模型基态的本质。还研究了该模型的有限温度特性，发现二维伊辛模型具有通用性的热相变。