基于群体蒙特卡洛方法精确计算基态熵：Shastry-Sutherland晶格上的反铁磁Ising模型
Accurate ground-state entropies from population Monte Carlo: The antiferromagnetic Ising model on the Shastry-Sutherland lattice
- Technische Universität Chemnitz（开姆尼茨工业大学）
- Universität Leipzig（莱比锡大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文用群体退火蒙特卡洛方法精确计算Shastry-Sutherland晶格反铁磁Ising模型的基态熵，结果与角转移矩阵重正化群方法一致，并发现局部能量团簇尺寸呈幂律衰减。
AI中文摘要：
我们展示了如何使用群体退火蒙特卡洛模拟方法高精度地计算基态熵。该方法在Shastry-Sutherland晶格上的经典反铁磁Ising模型上进行了测试，其中对角耦合强度被设为最近邻相互作用的两倍。在无外磁场的情况下，该模型已知在所有温度下都是无序的，并具有宏观简并的基态。我们发现每个格点的基态熵为$0.458\,777\,78(10)$，这与近期使用角转移矩阵重正化群方法的研究估计值吻合良好。通过考虑键构型、局部能量构型和自旋-自旋相关性，对采样的基态构型进行了分析。虽然所有观测结果都与基态的无序性质一致，但数值数据表明，具有不同于基态能级的局部能量的位点团簇的尺寸分布呈现幂律衰减。
英文摘要：
We demonstrate how the population annealing Monte Carlo simulation method can be used to compute the ground-state entropy to high precision. This approach is tested for the classical antiferromagnetic Ising model on the Shastry-Sutherland lattice with diagonal couplings chosen twice as strong as the nearest-neighbor interactions. In the absence of an external magnetic field, the model is known to be disordered at all temperatures, with a macroscopically degenerate ground state. We find the ground-state entropy to be $0.458\,777\,78(10)$ per site, which is in good agreement with the estimate of a recent study using the corner transfer matrix renormalization group method. The sampled ground-state configurations are analyzed by considering the bond configurations, the local-energy configurations, and the spin-spin correlations. While all observations are consistent with the disordered nature of the ground state, the numerical data suggest a power-law decay of the size distribution of clusters of sites with local energies different from the ground-state level.
