Thermodynamics and Statistical Mechanics of Viral Evolution Beyond Equilibrium

We study a model of viral evolution, in which viruses have a barrier to cell entry, mediated by their match to cell “key”, followed by a viral-type dependent immune response by the cell, and finally a probability to reproduce and mutate. These mutated viruses then go on to attack other cells in the model. Previously we found equilibrium behavior, featuring a phase transition as a function of temperature and immunity [PLOS One 2015 https://doi.org/10.1371/journal.pone.0137482]. Here we describe our studies of the behavior of this model as a dynamical system, and the nonequilibrium evolution of the quasispecies distribution including metastable states and other unexpected features.