Validity of the kink approximation to the tunneling action
  Coleman tunneling in a general scalar potential with two non-degenerate minima is known to have an approximation in terms of a piecewise linear triangular-shaped potential with sharp 'kinks' at the place of the local minima. This approximate potential has a regime where the existence of the bounce solution needs the scalar field to 'wait' for some amount of Euclidean time at one of the 'kinks'. We discuss under which conditions a kink approximation of locally smooth 'cap' regions provides a good estimate for the bounce action. 
Koushik Dutta, Cecelie Hector, Thomas Konstandin, Pascal M.   Vaudrevange, Alexander Westphal
hep-th