Solitons in anharmonic chains with ultra-long-range interatomic interactions

We study the influence of long-range interatomic interactions on the proper ties of supersonic pulse solitons in anharmonic chains. We show that in the case of ultra-long-range (e.g., screened Coulomb) interactions three diffe rent types of pulse solitons coexist in a certain velocity interval: one ty pe is unstable but the two others are stable. The high-energy stable solito n is broad and can be described in the quasicontinuum approximation. But th e low-energy stable soliton consists of two components, short-range and lon g-range ones, and can be considered as a bound state of these components.