Nonlinear dynamics of a symmetric Davydov–Fröhlich dimer

An analysis of a dimer, modeling two interacting equal monomer units in which complex monomer excitations can arise, is performed. The analyzed classical dynamical system corresponds to the basic unit of a novel microscopic model offered by a unified theory of the well-known Davydov and Fröhlich models of energy transport in proteins. The transition between regular and chaotic dynamics, which depends on the energy pumping and the monomer–monomer interaction parameters, is analyzed. There is a region of values of the relevant parameters when the system is either in an ordered and stable state or goes through a succession of disordered and unstable states. This could have important biological applications.