## Time fractional diffusion: A discrete random walk approach.(English)Zbl 1009.82016

Summary: The time fractional diffusion equation is obtained from the standard diffusion equation by replacing the first-order time derivative with a fractional derivative of order $$\beta\in (0,1)$$. From a physical view-point this generalized diffusion equation is obtained from a fractional Fick law which describes transport processes with long memory. The fundamental solution for the Cauchy problem is interpreted as a probability density of a self-similar non-Markovian stochastic process related to a phenomenon of slow anomalous diffusion. By adopting a suitable finite-difference scheme of solution, we generate discrete models of random walk suitable for simulating random variables whose spatial probability density evolves in time according to this fractional diffusion equation.

### MSC:

 82C41 Dynamics of random walks, random surfaces, lattice animals, etc. in time-dependent statistical mechanics 82C70 Transport processes in time-dependent statistical mechanics 60G50 Sums of independent random variables; random walks

### Keywords:

anomalous diffusion; random walks; fractional derivatives
Full Text: