Transient Trapping into Metastable States in Systems with Competing Orders

The quench dynamics of a system involving two competing orders is investigated using a Ginzburg-Landau theory with relaxational dynamics. We consider the scenario where a pump rapidly heats the system to a high temperature, after which the system cools down to its equilibrium temperature. We study the evolution of the order parameter amplitude and fluctuations in the resulting time-dependent free-energy landscape. Exponentially growing thermal fluctuations dominate the dynamics. The system typically evolves into the phase associated with the faster-relaxing order parameter, even if it is not the global free-energy minimum. This theory offers a natural explanation for the widespread experimental observation that metastable states may be induced by laser-induced collapse of a dominant equilibrium order parameter.