I am following along Breuer and Petruccione's book . I would like to know if the property ρ†=ρ is preserved for evolution that is described by the Born Approximation.
For a Hilbert space Hs⊗Hb describing a system of interest and some reservoir/bath, we consider a time-independent Hamiltonian of the form H=Hs⊗Ib+Is⊗Hb+gHint
The full density matrix of the combined system and bath σ(t) evolves via the von Neumann equation dσI(t)dt=−i[V(t),σI(t)]
If we define the reduced density matrix describing the system as the following partial trace ρ(t):=Trb[σ(t)]
My Question: Suppose that ρ(0)†=ρ(0) so that the initial density matrix is Hermitian. How can you use the above equation to show that ρ(t)†=ρ(t) for t>0?
Is this possible? In the literature, I sometimes come across some statements that Lindblad equations preserve Hermicity (Lindblad equations being the above equation, after taking the Markov Approximation and then the secular/rotating-wave approximation).
Is it possible to prove this from this equation of motion? Or do we need additional assumptions? Or can this be more generally proven for ρ without specifying to a particular evolution equation?
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