Qian Xiaohui, Yu Gaotian, Zhou Nengji
School of Physics, Hangzhou Normal University, Hangzhou 311121, China.
Phys Rev E. 2023 Jun;107(6-1):064108. doi: 10.1103/PhysRevE.107.064108.
With large-scale Monte Carlo simulations, we investigate the nonsteady relaxation at the dynamic depinning transition in the two-dimensional Gaussian random-field Ising model. The dynamic scaling behavior is carefully analyzed, and the transition fields as well as static and dynamic exponents are accurately determined based on the short-time dynamic scaling form. Different from the usual assumption, two distinguished growth processes of spatial correlation lengths for the velocity and height of the domain wall are found. Thus, the universality class of the depinning transition is established, which significantly differs from that of the quenched disorder equation but agrees with that of the recent experiment as well as other simulations works. Under the influence of the mesoscopic time regime, the crossover from the second-order phase transition to the first-order one is confirmed in the weak-disorder regime, yielding an abnormal disorder-dependent nature of the criticality.
通过大规模蒙特卡罗模拟，我们研究了二维高斯随机场伊辛模型中动态脱钉转变处的非稳态弛豫。仔细分析了动态标度行为，并基于短时动态标度形式精确确定了转变场以及静态和动态指数。与通常的假设不同，发现了畴壁速度和高度的空间相关长度的两种不同增长过程。因此，确立了脱钉转变的普适类，它与淬火无序方程的普适类有显著差异，但与最近的实验以及其他模拟工作的结果一致。在介观时间尺度的影响下，在弱无序区域证实了从二阶相变到一阶相变的交叉，产生了临界性的异常无序依赖性。
