Displacement of transport processes on networked topologies

Abstract

Consider a particle whose position evolves along the edges of a network. One definition for the displacement of a particle is the length of the shortest path on the network between the current and initial positions of the particle. Such a definition fails to incorporate information of the actual path the particle traversed. In this work we consider another definition for the displacement of a particle on networked topologies. Using this definition, which we term the winding distance, we demonstrate that for Brownian particles, confinement to a network can induce a transition in the mean squared displacement from diffusive to ballistic behaviour, $⟨x^2(t)⟩\propto t^2$ for long times. A multiple scales approach is used to derive a macroscopic evolution equation for the displacement of a particle and uncover a topological condition for whether this transition in the mean squared displacement will occur. Furthermore, for networks satisfying this topological condition, we identify a prediction of the timescale upon which the displacement transitions to long-time behaviour. Finally, we extend the investigation of displacement on networks to a class of anomalously diffusive transport processes, where we find that the mean squared displacement at long times is affected by both network topology and the character of the transport process.

arXiv comment22 pages, 8 figures

References in corpus (6)

• Random walk and trapping processes on scale-free networks
• Diffusion and subdiffusion of interacting particles on comb-like structures
• Random walk on Bethe lattice and hyperbolic geometry
• Walks on Apollonian networks
• The two-particle problem in comb-like structures
• Propagators of random walks on comb lattices of arbitrary dimension