Imaginary-field-driven phase transition for the 2D Ising antiferromagnet: A fidelity-susceptibility approach
Imaginary-field-driven phase transition for the 2D Ising antiferromagnet: A fidelity-susceptibility approach
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DOI：
10.1016/j.physa.2020.124731
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发表时间：
2020-05
影响因子：
3.3
通讯作者：
Y. Nishiyama
中科院分区：
文献类型：
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作者：
Y. Nishiyama
用转移矩阵方法研究了正方晶格Ising反铁磁体在虚磁场H= i θ Tscin 2作用下的“拓扑”角θ和温度T.在这里，作为探测有序-无序相变的探针，我们采用了扩展版本的保真度磁化率χ F（θ），即使对于这样的非厄米传输矩阵也是有意义的。作为初步的调查，对于θ的中间值，我们检查了χ F（θ）的有限尺寸标度行为，并发现了临界性的明显特征;注意，磁化率在内尔温度下表现出弱（对数）奇异性。因此，我们转向分析相边界在θ= π处的幂律奇异性。在θ− π适当标度的情况下，χ F（θ）数据被转换为交叉标度公式，表明相边界是凹形的。这一特点与平均场理论的特点形成了鲜明的对比。
The square-lattice Ising antiferromagnet subjected to the imaginary magnetic field H= i θ T∕ 2 with the “topological” angle θ and temperature T was investigated by means of the transfer-matrix method. Here, as a probe to detect the order–disorder phase transition, we adopt an extended version of the fidelity susceptibility χ F (θ), which makes sense even for such a non-hermitian transfer matrix. As a preliminary survey, for an intermediate value of θ, we examined the finite-size-scaling behavior of χ F (θ), and found a pronounced signature for the criticality; note that the magnetic susceptibility exhibits a weak (logarithmic) singularity at the Néel temperature. Thereby, we turn to the analysis of the power-law singularity of the phase boundary at θ= π. With θ− π scaled properly, the χ F (θ) data are cast into the crossover scaling formula, indicating that the phase boundary is shaped concavely. Such a feature makes a marked contrast to that of the mean-field theory.