Field theory for a reaction-diffusion model of quasispecies dynamics - art. no. 051909

RNA viruses are known to replicate with extremely high mutation rates. Thes e rates are actually close to the so-called error threshold. This threshold is in fact a critical point beyond which genetic information is lost throu gh a second-order phase transition, which has been dubbed as the "error cat astrophe," Here we explore this phenomenon using a field theory approximati on to the spatially extended Swetina-Schuster quasispecies model [J. Swetin a and P. Schuster, Biophys. Chem. 16, 329 (1982)], a single-sharp-peak land scape, In analogy with standard absorbing-state phase transitions, we devel op a reaction-diffusion model whose discrete rules mimic the Swetina-Schust er model. The field theory representation of the reaction-diffusion system is constructed. The proposed field theory belongs to the same universality class as a conserved reaction-diffusion model previously proposed [F. van W ijland et al., Physica A 251, 179 (1998)]. From the field theory, we obtain the full set of exponents that characterize the critical behavior at the e rror threshold. Our results present the error catastrophe from a different point of view and suggest that spatial degrees of freedom can modify severa l mean-field predictions previously considered, leading to the definition o f characteristic exponents that could be experimentally measurable.