Unimodal wavetrains and solitons in convex Fermi–Pasta–Ulam chains
Unimodal wavetrains and solitons in convex Fermi–Pasta–Ulam chains
We consider atomic chains with nearest neighbour interactions and study periodic and homoclinic travelling waves which are called wave trains and solitons, respectively. Our main result is a new existence proof which relies on the constrained maximisation of the potential energy and exploits the invariance properties of an improvement operator. …