title: Epidemic threshold of the susceptible-infected-susceptible model on complex networks.
abstract: We demonstrate that the susceptible-infected-susceptible (SIS) model on complex networks can have an inactive Griffiths phase characterized by a slow relaxation dynamics. It contrasts with the mean-field theoretical prediction that the SIS model on complex networks is active at any nonzero infection rate. The dynamic fluctuation of infected nodes, ignored in the mean field approach, is responsible for the inactive phase. It is proposed that the question whether the epidemic threshold of the SIS model on complex networks is zero or not can be resolved by the percolation threshold in a model where nodes are occupied in degree-descending order. Our arguments are supported by the numerical studies on scale-free network models.
authors.affiliation: Department of Physics, University of Seoul, Seoul 130-743, Korea.
authors.forename: Hyun Keun
authors.initials: HK
authors.lastname: Lee
authors.forename: Pyoung-Seop
authors.initials: PS
authors.lastname: Shim
authors.forename: Jae Dong
authors.initials: JD
authors.lastname: Noh
mesh_terms: D000818:Animals; D003141:Communicable Diseases / Q000453:epidemiology*; D003198:Computer Simulation; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D018562:Disease Transmission, Infectious / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D015233:Models, Statistical; D016016:Proportional Hazards Models; D018570:Risk Assessment / Q000379:methods