This translates to ⟨ j ‖ K ( 1 ) ‖ j ⟩ = ⟨ j ‖ K ( 1 ) ‖ j ⟩ ¯ ¯ , ⟨ j ‖ K ( 1 ) ‖ j − − 1 ⟩ = − − ⟨ j − − 1 ‖ K ( 1 ) ‖ j ⟩ ¯ ¯ , leading to j 0 ( j 1 + j 1 ¯ ¯ ) = 0 , | B j | ( | ξ ξ j | 2 − − e − − 2 i β β j ) = 0 , where β j is the angle of B j on polar form. For | B j | ≠ 0 follows | ξ ξ j | 2 = 1 and ξ ξ j = 1 is chosen by convention. There are two possible cases: