where the anticommutator term -1 2 â † â, ρS causes population decay as well as decoherence among states, whereas the âρ S â † term (refilling term) makes the population reappear in the new state that the decay leads to (in this case, the state with one fewer photons). In order to make connections to other methods of propagating loss, the Lindblad master equation can be written in an equivalent form as