Generalized model-independent approach to intrinsic decoherence
  A formalism is presented to express decoherence both in the markovian and nonmarkovian regimes and both dissipative and nondissipative in isolated systems. The main physical hypothesis, already contained in the literature, amounts to allowing some internal parameters of the system to evolve in a random fashion. This formalism may also be applicable to open quantum systems. 
D. Salgado and J.L. Sanchez-Gomez