论文标题
（正方形）旋转冰的磁性单孔的现场理论
Field Theory for Magnetic Monopoles in (Square, Artificial) Spin Ice
论文作者
论文摘要
从更通用到更具体的过程中，我们提出了一个平衡场理论，描述了拓扑电荷和磁单孔的旋转冰系统。我们表明，对于图上的自旋冰，高斯近似值中的熵相互作用是图形laplacian矩阵的倒数，而外部电荷的筛选函数是筛选的laplacian的倒数。我们将治疗方面的治疗方案与方形和pyrochlore冰有关。对于平方冰，我们以电荷和电流之间的对称性来强调直接和垂直结构之间的无量规二元性，这是二维环境中磁性碎片的典型代表。我们得出了旋转，拓扑电荷和电流的结构因子，相关性，相关长度和敏感性。我们表明，低温下相关长度的差异是指数呈指数，并且与均方根电荷成反比。在三维中，单孔之间的真实和熵相互作用均为3D-Coulomb，而在二维中，前者是3D-Coulomb和后者的2D-Coulomb或对数，导致捏合点的对应性和破坏电荷筛选的奇异性较弱。这表明方冰的单极血浆是磁性绝缘子。
Proceeding from the more general to the more concrete, we propose an equilibrium field theory describing spin ice systems in terms of topological charges and magnetic monopoles. We show that for a spin ice on a graph, the entropic interaction in a Gaussian approximation is the inverse of the graph Laplacian matrix, while the screening function for external charges is the inverse of the screened laplacian. We particularize the treatment to square and pyrochlore ice. For square ice we highlight the gauge-free duality between direct and perpendicular structure in terms of symmetry between charges and currents, typical of magnetic fragmentation in a two-dimensional setting. We derive structure factors, correlations, correlation lengths, and susceptibilities for spins, topological charges, and currents. We show that the divergence of the correlation length at low temperature is exponential and inversely proportional to the mean square charge. While in three dimension real and entropic interactions among monopoles are both 3D-Coulomb, in two dimension the former is a 3D-Coulomb and the latter 2D-Coulomb, or logarithmic, leading to weak singularities in correspondence of the pinch points and destroying charge screening. This suggests that the monopole plasma of square ice is a magnetic charge insulator.
