Domain Walls and Decay Rate of the Excited Vacua in the Large N   Yang-Mills Theory
  In the (non-supersymmetric) Yang-Mills theory in the large N limit there exists an infinite set of non-degenerate vacua. The distinct vacua are separated by domain walls whose tension determines the decay rate of the false vacua. I discuss the phenomenon from a field-theoretic point of view, starting from supersymmetric gluodynamics and then breaking supersymmetry, by introducing a gluino mass. By combining previously known results, the decay rate of the excited vacua is estimated, \Gamma \sim \exp (-const \times N^4). The fourth power of N in the exponent is a consequence of the fact that the wall tension is proportional to N. 
M. Shifman