  We present a study of static and frequency-dependent diffusion with
anisotropic thermally activated transition rates in a two-dimensional bond
percolation system. The approach accounts for temperature effects on diffusion
coefficients in disordered anisotropic systems. Static diffusion shows an
Arrhenius behavior for low temperatures with an activation energy given by the
highest energy barrier of the system. From the frequency-dependent diffusion
coefficients we calculate a characteristic frequency $\omega_{c}\sim 1/t_{c}$,
related to the time $t_c$ needed to overcome a characteristic barrier. We find
that $\omega_c$ follows an Arrhenius behavior with different activation
energies in each direction.

Disordered Systems and Neural Networks;Statistical Mechanics