论文标题
$ 2 $ d Ising Antiferromagnet的虚场驱动相变：一种保真度敏感的方法
Imaginary-field-driven phase transition for the $2$D Ising antiferromagnet: A fidelity-susceptibility approach
论文作者
论文摘要
经过传输矩阵方法研究了遭受假想磁场$ h =iθt /2 $和温度$ t $的平方晶格抗铁磁体$ h =iθt /2 $。在这里，作为检测订单disorder阶段过渡的探测，我们采用了保真度易感性的扩展版本$χ_f^{（θ）} $，即使对于这样的非Hermitian传输矩阵也是有意义的。作为初步调查，对于$θ$的中间值，我们检查了$χ_f^{（θ）} $的有限大小规模行为，并为关键性找到了明显的签名；请注意，磁化率在Néel温度下表现出弱（对数）奇异性。因此，我们转向对$θ=π$的相边界的幂律奇异性的分析。随着$θ-π$正确缩放，$χ_f^{（θ）} $数据被施放到交叉缩放公式中，表明相位边界是缩合的。这样的功能与平均场理论的形成鲜明对比。
The square-lattice Ising antiferromagnet subjected to the imaginary magnetic field $H=i θT /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.
