We numerically investigate the nonequilibrium critical dynamics in three-dimensional anisotropic antiferromagnets in the presence of an external magnetic field. The phase diagram of this system exhibits two critical lines that meet at a bicritical point. The nonconserved components of the staggered magnetization order parameter couple dynamically to the conserved component of the magnetization density along the direction of the external field. Employing a hybrid computational algorithm that combines reversible spin precession with relaxational Monte Carlo updates, we study the aging scaling dynamics for the model C critical line, identifying the critical initial slip, autocorrelation, and aging exponents for both the order parameter and the conserved field, thus also verifying the dynamic critical exponent. We further probe the model F critical line by investigating the system size dependence of the characteristic spin wave frequencies near criticality and measure the dynamic critical exponents for the order parameter including its aging scaling at the bicritical point.

中文翻译：

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各向异性反铁磁体在外部磁场中的临界动力学

我们数值研究三维磁场各向异性反铁磁体在外部磁场的存在下的非平衡临界动力学。该系统的相图显示了两条在双临界点相遇的临界线。交错的磁化阶数参数的非守恒分量沿外场方向动态耦合到磁化密度的守恒分量。我们采用混合计算算法，将可逆自旋旋进与松弛蒙特卡罗更新相结合，研究了模型C临界线的老化定标动力学，确定了阶次参数和守恒场的临界初始滑移，自相关和老化指数，因此也验证了动态临界指数。