Discrete breathers in honeycomb Fermi–Pasta–Ulam lattices

  title={Discrete breathers in honeycomb Fermi–Pasta–Ulam lattices},
  author={Jonathan A. D. Wattis and Lauren M. James},
  journal={Journal of Physics A},
We consider the two-dimensional Fermi–Pasta–Ulam lattice with hexagonal honeycomb symmetry, which is a Hamiltonian system describing the evolution of a scalar-valued quantity subject to nearest neighbour interactions. Using multiple-scale analysis we reduce the governing lattice equations to a nonlinear Schrodinger equation coupled to a second equation for an accompanying slow mode. Two cases in which the latter equation can be solved and so the system decoupled are considered in more detail… 

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