Pospíšilová Eva, Krčmár Roman, Gendiar Andrej, Šamaj Ladislav
Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 84511 Bratislava, Slovakia.
Phys Rev E. 2020 Jul;102(1-1):012125. doi: 10.1103/PhysRevE.102.012125.
We consider the symmetric two-state 16-vertex model on the square lattice whose vertex weights are invariant under any permutation of adjacent edge states. The vertex-weight parameters are restricted to a critical manifold which is self-dual under the gauge transformation. The critical properties of the model are studied numerically with the Corner Transfer Matrix Renormalization Group method. Accuracy of the method is tested on two exactly solvable cases: the Ising model and a specific version of the Baxter eight-vertex model in a zero field that belong to different universality classes. Numerical results show that the two exactly solvable cases are connected by a line of critical points with the polarization as the order parameter. There are numerical indications that critical exponents vary continuously along this line in such a way that the weak universality hypothesis is violated.
我们考虑正方形晶格上的对称双态16顶点模型，其顶点权重在相邻边状态的任何置换下都是不变的。顶点权重参数被限制在一个在规范变换下自对偶的临界流形上。用角转移矩阵重整化群方法对该模型的临界性质进行了数值研究。该方法的准确性在两个精确可解的情形上进行了检验：伊辛模型和零场中属于不同普适类的巴克斯特八顶点模型的一个特定版本。数值结果表明，这两个精确可解的情形由一条以极化作为序参量的临界点线相连。有数值迹象表明，临界指数沿着这条线连续变化，以至于弱普适性假设被违反。
