Many-body methods in agent-based epidemic models

Gilberto M. Nakamura ∗ and Alexandre S. Martinez † Universidade de São Paulo, Ribeirão Preto 14040-901, Brazil Abstract The susceptible-infected-susceptible (SIS) agent-based model is usually employed in the investigation of epidemics. The model describes a Markov process for a single communicable disease among susceptible (S) and infected (I) agents. However, the disease spreading forecasting is often restricted to numerical simulations, while analytic formulations lack both general results and perturbative approaches since they are subjected to asymmetric time generators. Here, we discuss perturbation theory, approximations and application of many-body techniques in epidemic models in the framework for squared norm of probability vector |P (t)|2, in which asymmetric time generators are replaced by their symmetric counterparts.