Figure 1:
(Top) In conventional time evolution of quantum systems, different input states |ψ^{in}〉 lead to different output states |ψ^{out}〉 if a unitary operation U is applied. (Bottom) Quantum state preparation by reservoir engineering takes a different approach. If the interaction of the system with a bath is engineered such that |ψ_{fin}〉 is the unique steady state of the dissipative process, then the system is driven into this state irrespective of the initial state initiating the evolution paths ρ_{1}, ρ_{2}, etc.