Topological symmetry breaking: Domain walls and partial instability of   chiral edges
  In 2D topological systems chiral edges may exhibit a spectral change due to the formation of a Bose condensate and partial confinement in the bulk according to the topological symmetry breaking (TSB) mechanism. We analyze in detail what happens in the bulk as well as on the edge for a set of simple chiral fractional quantum Hall systems. TSB corresponds to the spontaneous breaking of a global discrete symmetry and therefore to the appearance of domain walls in the bulk and kinks on the edge. The walls are locally metastable and break if a confined particle-hole pair is created. 
F.A. Bais and S.M. Haaker
cond-mat.str-el