Quantum stability of non-linear wave type solutions with intrinsic mass   parameter in QCD
  The problem of existence of a stable vacuum field in a pure quantum chromodynamics (QCD) is revised. Our approach is based on using classical stationary non-linear wave type solutions with intrinsic mass scale parameter. Such solutions can be treated as quantum mechanical wave functions describing massive spinless states in quantum theory. We verify whether non-linear wave type solutions can form a stable vacuum field background within the framework of effective action formalism. We demonstrate that there is a special class of stationary generalized Wu-Yang monopole solutions which are stable against quantum gluon fluctuations. 
Youngman Kim, Bum-Hoon Lee, D.G. Pak, Chanyong Park, Takuya Tsukioka
hep-th