Dynamics and nonequilibrium states in the Hamiltonian mean-field model: A closer look

The slow-relaxation dynamics of the Hamiltonian mean-field model, when the evolution starts from water-bag initial conditions, was reexamined. First, an attempt was made to revise the evidence that would support the existence of quasitationary states in the nonequilibrium dynamics of the model. In this regard, it was shown that the plateaus in the temporal evolution of the nonequilibrium temperature T(t) are a mere artifact to the use of a logarithmic scale for the time axis in the plot of T(t). Furthermore, a detailed analysis of the evolution of the nonequilibrium temperature showed that the dynamics can be decomposed into two well-defined dynamical regimes.