Normally Ordered Expansion of the Even-Power of the Radial Coordinate Operator
Fan Hong‐Yi · Chinese Physics Letters · 2001
By virtue of the technique of integration within an ordered product of operators we derive the concise normally ordered expansion of the even-power of the radial coordinate operator via the equation = ∫ d 3 x | x ⟩⟨ x | r , where | x ⟩ is the three-dimensional coordinate eigenvector, and r = ( x 2 + y 2 + z 2 ) 1/2 . The application to perturbation theory is briefly discussed.