Monin, Alexander2010-12-102010-12-102010-08https://hdl.handle.net/11299/97759University of Minnesota Ph.D. dissertation. August 2010. Major: Physics. Advisor: Dr. Mikhail Voloshin. 1 computer file (PDF); v, 96 pages, appendices A-B.In present study we consider decays of metastable strings and walls. Both cases of zero and finite temperature are considered. An appropriate interpretation of the thermal result allowed to find the probability of the decay in collisions of Goldstone bosons. The developed technique was used to find the rate of e^+e^- pair production in external field stimulated by photon.en-USBreakingDecayFieldPhotonStringsWallPhysicsThesis or Dissertation