Zusammenfassung

We study transport properties such as conductance and diffusion of complex networks such as scale-free and Erdos-Renyi networks. We consider the equivalent conoductance G between two arbitrarily chosen nodes of random scale-free networks with degree distribution P (k) ∼ k−λ and Erd˝ s-R´ nyi networks in which each link has the o e same unit resistance. Our theoretical analysis for scale-free networks predicts a broad range of values of G (or the related diffusion constant D), with a power-law tail distribution ΦSF (G) ∼ G−gG , where gG = 2λ − 1. We confirm our predictions by simulations of scale-free networks solving the Kirchhoff equations for the conductance between a pair of nodes. The power-law tail in ΦSF (G) leads to large values of G, thereby significantly improving the transport in scale-free networks, compared to Erd˝ s-R´ nyi o e networks where the tail of the conductivity distribution decays exponentially. Based on a simple physical “transport backbone” picture we suggest that the conductances of scale-free and Erd˝ s-R´ nyi networks can be approximated by ckA kB /(kA + kB ) o e for any pair of nodes A and B with degrees kA and kB . Thus, a single parameter c characterizes transport on both scale-free and Erd˝ s-R´ nyi networks. o e

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