Remarks on sufficient conditions for conservativity of minimal quantum   dynamical semigroups
  We obtain sufficient conditions for conservativity of minimal quantum dynamical semigroup by modifying and extending the method used in [Chebotarev and Fagnola, J. Funct. Anal. 153(1998), 382-404]. Our criterion for conservativity can be considered as a complement to Chebotarev and Fagnola's conditions. In order to show that our conditions are useful, we apply our results to a concrete example(a model of heavy ion collision). 
C. Bahn C. K. Ko and Y. M. Park