Kim Eunhye, Kim Bongsoo, Lee Sung Jong
Department of Physics, Changwon National University, Changwon 641-773, Korea.
Phys Rev E Stat Nonlin Soft Matter Phys. 2003 Dec;68(6 Pt 2):066127. doi: 10.1103/PhysRevE.68.066127. Epub 2003 Dec 31.
We investigate the nonequilibrium critical dynamics of antiferromagnetic Ising model on a two-dimensional triangular lattice via dynamic Monte Carlo simulation employing spin-flip kinetics. Macroscopic degeneracy of the ground state originating from geometric frustration fundamentally affects the nonequilibrium dynamics of the system. In particular, the defects and the loose spins (whose flip costs no energy) play key roles in the dynamics. The long-time evolution is characterized by a critical dynamic scaling with a growing length scale xi(t). With random initial configurations, xi(t) exhibits a subdiffusive growth in time, xi(t) approximately t(1/z) with 1/z approximately 0.43, while xi(t) shows a diffusive growth with z=2 for the relaxation within the dominant sector of the ground-state manifold. The nonequilibrium critical dynamics therefore exhibits an interesting initial-state dependence. Persistence and the two-time temporal properties are also discussed.
我们通过采用自旋翻转动力学的动态蒙特卡罗模拟，研究了二维三角形晶格上反铁磁伊辛模型的非平衡临界动力学。源于几何阻挫的基态宏观简并性从根本上影响了系统的非平衡动力学。特别是，缺陷和松散自旋（其翻转不消耗能量）在动力学中起着关键作用。长时间演化的特征是具有不断增长的长度尺度(\xi(t))的临界动态标度。对于随机初始构型，(\xi(t))随时间呈现亚扩散增长，(\xi(t)\approx t^{1/z})，其中(1/z\approx0.43)，而对于基态流形主导扇区内的弛豫，当(z = 2)时(\xi(t))呈现扩散增长。因此，非平衡临界动力学表现出有趣的初始态依赖性。还讨论了持续性和双时时间特性。
