发表机构
School of Physics, Beijing Institute of Technology（北京理工大学物理学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出将磁场算符作为独立算符类的SSE量子蒙特卡洛框架，使场算符与其他相互作用算符在更新中可相互转化，在二维反铁磁海森堡模型中验证了正确性与竞争力。
AI 中文摘要
带环更新的随机级数展开（SSE）量子蒙特卡洛方法是量子自旋和玻色子系统最强大的方法之一。在标准表述中，磁场项通常被吸收到海森堡相互作用中——这一策略在广泛的场强范围内已被证明非常高效。在这项工作中，我们提出了一个更通用的SSE框架，其中磁场算符被当作一个独立的算符类处理，使其能够与所有其他算符平等地参与蒙特卡洛更新。重要的是，场算符和其他相互作用算符在更新过程中可以相互转化。我们以二维反铁磁海森堡模型在磁场中的情况作为具体例子来演示该算法。模拟结果与传统算法的结果一致，证实了新表述的正确性。对积分自相关时间的比较表明，新算法具有竞争力。这种灵活性不仅便于测量与算符相关的可观测量，而且为更广泛的问题类别提供了潜在的计算优势。
英文摘要
The Stochastic Series Expansion (SSE) quantum Monte Carlo method with loop updates is among the most powerful approaches for quantum spin and boson systems. In the standard formulation, the magnetic field term is routinely absorbed into the Heisenberg interactions---a strategy that has proven highly efficient across a wide range of field strengths. In this work, we propose a more general SSE framework in which the magnetic field operator is treated as an independent operator class, enabling it to participate in Monte Carlo updates on an equal footing with all other operators. Importantly, the field operator and other interaction operators can transform into one another during the update process. We demonstrate this algorithm using the two-dimensional antiferromagnetic Heisenberg model in a magnetic field as a concrete example. The simulation results agree with those of the conventional algorithm, confirming the correctness of the new formulation. A comparison of the integrated autocorrelation time shows that the new algorithm is competitive. This flexibility not only facilitates measurements of observables associated with operators but also offers potential computational advantages for a broader class of problems.
Comments8 pages, 6 figures
