The stationary sine-Gordon equation on metric graphs: Exact analytical   solutions for simple topologies
  We consider the stationary sine-Gordon equation on metric graphs with simple topologies. The vertex boundary conditions are provided by flux conservation and matching of derivatives at the star graph vertex. Exact analytical solutions are obtained. It is shown that the method can be extended for tree and other simple graph topologies. Applications of the obtained results to branched planar Josephson junctions and Josephson junctions with tricrystal boundaries are discussed. 
K. Sabirov, S. Rakhmanov, D. Matrasulov, H. Susanto
nlin.SI cond-mat.supr-con math-ph math.MP