“…Given two coherent states ρ and σ, the question of coherence manipulation is to study whether there exists some free operation Φ such that Φ(ρ) = σ. Attempts have been made to uncover the fundamental laws of its behaviour under free operations [8,12,14,15,22,[40][41][42][43]. In [22], it is proved that, for qubit states ρ, σ with Bloch vector r = (r x , r y , r z ) t and s = (s x , s y , s z ) t , ρ can be converted into σ by stochastic SIO if and only if the following inequalities are fulfilled…”