Department of Mathematics2024-11-0920100219-887810.1142/S02198878100046832-s2.0-77958580851http://dx.doi.org/10.1142/S0219887810004683https://hdl.handle.net/20.500.14288/12580We study general properties of dynamical maps preserving Hermiticity and quasi-Hermiticity, and prove that the generator of a dynamical semigroup is always a pseudo-Hermitian operator. Moreover, improving a previous proposal by Jakob and Stenholm, we introduce two new Lyapunov functionals for degenerate open systems, and apply such results to a physical example.Physics, mathematical modelsJournal Article283494700007Q27298