Critical Dynamics of Anisotropic Antiferromagnets in an External Field

We numerically investigate the non-equilibrium critical dynamics in three-dimensionalanisotropic antiferromagnetsin the presence of an external magnetic field. The phase space of this system exhibits two critical lines which meet at a bicritical point. In this system, the non-conserved components of staggered magnetization order parameter couple dynamically to the conserved component of the magnetization density along the direction of the external field. By 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, decay and aging collapse exponents, thus also verifying the dynamic critical exponent. We also probe the dynamic exponent of the model F critical line by investigating the system-size dependence of the characteristic spin wave frequencies near criticality. Furthermore, we investigate the aging scaling behavior of the slow order parameter and conserved field near the bicritical point.