- #1

perishingtardi

- 21

- 1

Suppose B is an operator that commutes with A. How could I show that

[tex]\langle u_i | B | u_j \rangle = 0 \qquad (a_i \neq a_j)?[/tex]

I have tried the following but not sure how to proceed:

[tex]AB - BA=0\\ \implies \langle u_i | AB | u_j \rangle - \langle u_i | BA | u_j \rangle = 0[/tex]