Deformed Bubbles and Lorentz Invariance in Vacuum Decay
  Recently, questions have been raised about the role of Lorentz invariance in false vacuum decay. It has been argued that infinities may arise in an integration over Lorentz-boosted final states. This suggestion motivates a Minkowski-space analysis of the decay rate. We attempt to illuminate features of the amplitude computation, and argue that the total rate including excitations is both finite and Lorentz invariant. 
Michael Dine, Patrick Draper, and Chang-Soon Park
hep-th