Anosov properties of a symplectic map with time-reversal symmetry

This study presents a specific symplectic map, derived from a Hamiltonian, as a model that exhibits time-reversal symmetry on a microscopic scale. Based on the analysis, any initial density function, defined almost everywhere, converges to a uniform distribution in terms of mixing (irreversible behavior) on a macroscopic level. Furthermore, we established that this mixing invariant measure is a unique equilibrium state, unique Sinai–Ruelle–Bowen measure, and physical measure. Additionally, through analytical proof, we have shown that the Kolmogorov–Sinai entropy representing the average information gain per unit time is positive. This was achieved by validating Pesin’s formula and demonstrating that the critical exponent of the Lyapunov exponent is 1/2.