Recent Developments in Quantum Vacuum Energy for Confined Fields
  Quantum vacuum energy entered hadronic physics through the zero-point energy parameter introduced into the bag model. Estimates of this parameter led to apparent discordance with phenomenological fits. More serious were divergences which were omitted in an ad hoc manner. New developments in understanding Casimir self-stresses, and the nature of surface divergences, promise to render the situation clearcut. 
K. A. Milton