Equation Icon  [ ] vac iβf(Ω) [ ] vac′ oˆ(Ω) = ℙ 𝜃f (Ω ) 𝕊sqz[r,𝜃]ˆa e = 𝕊sqz r,𝜃 + 𝜃f(Ω) ˆa , (435 )