Tendency towards maximum complexity in a nonequilibrium isolated system -: art. no. 066116

The time evolution equations of a simplified isolated ideal gas, the tetrahedral gas, are derived. The dynamical behavior of the Lopez-Ruiz-Mancini-Calbet complexity CR. Lopez-Ruiz, H. L. Mancini, and X. Calbet, Phys. Lett. A 209, 321 (1995)] is studied in this system. In general, it is shown that the complexity remains within the bounds of minimum and maximum complexity. We find that there are certain restrictions when the isolated tetrahedral gas evolves towards equilibrium. In addition to the well-known increase in entropy, the quantity called disequilibrium decreases monotonically with time. Furthermore, the trajectories of the system in phase space approach the maximum complexity path as it evolves toward equilibrium.