Dynamics of solitary wave scattering in the Fermi-Pasta-Ulam model

In this Letter, we study the scattering dynamics of a pair of solitary waves in the Fermi-Pasta-Ulam model with interaction potential V(x)=alphax(2)/2+x(4)/4 and establish a quantitative connection between the scattering property and the energy transport behavior. The energy and momentum conservation laws are obtained and the scattering rates of solitary waves are calculated. Our studies suggest that the anharmonic limit model with alpha=0 can be taken as a paradigm model for studying lattice solitary waves.