U ( R ) † † T ^ ^ m ( j ) U ( R ) = ( 1 + i ϵ ϵ n ^ ^ ⋅ ⋅ J → → ℏ ℏ + O ( ϵ ϵ 2 ) ) T ^ ^ m ( j ) ( 1 − − i ϵ ϵ n ^ ^ ⋅ ⋅ J → → ℏ ℏ + O ( ϵ ϵ 2 ) ) = ∑ ∑ m ′ ⟨ ⟨ j , m ′ | ( 1 + i ϵ ϵ n ^ ^ ⋅ ⋅ J → → ℏ ℏ + O ( ϵ ϵ 2 ) ) | j , m ⟩ ⟩ T ^ ^ m ′ ( j )