A canonical Hamiltonian for open quantum systems

If an open quantum system is initially uncorrelated from its environment, then dynamics can be written in terms of a Lindblad-form master equation. The equation divided into unitary piece, represented by effective Hamiltonian, and dissipative hermiticity-preserving superoperator; however, the division pieces non-unique. For finite-dimensional systems, we resolve this non-uniqueness specifying norm on space superoperators defining canonical Hamiltonian to one whose dissipator minimal. We show that thus defined equivalent Lindblad, it uniquely specified requiring dissipator's jump operators traceless, extending uniqueness result known previously special case Markovian equations. weakly coupled give recursive formula for computing arbitrary orders perturbation theory, which think as perturbative scheme renormalizing system's bare Hamiltonian.