Kinetics of Domain Growth: Universality of Kinetic Exponents

We have studied the growth kinetics of several systems with highly degenerate ground states which were quenched from a high ($T\gg T_c$) to a low temperature ($T\cong 0$). The mean domain size $R$ increases algebraically with time as $R\cong t^n$, where surprisingly the value of $n$ is observed to fall into one of two universality classes for all the models studied. We observe a distinct crossover from one universality class to the other as the spin interaction is varied.