- #1

pfollansbee

- 14

- 0

## Homework Statement

Let [tex]ψ(r)= c_n ϕ_n (r) + c_m ϕ_m (r) [/tex] where [tex]ϕ_n(r)[/tex] and [tex] ϕ_m (r)[/tex] are independent functions.

Show that the condition that Â is Hermitian leads to

[tex]∫ψ_m (r)^* Âψ_n (r)dr = ∫Â^* ψ_m (r)^* ψ_n (r)dr[/tex]

## Homework Equations

[tex]∫ψ(r)^* Â ψ(r)dr = ∫Â^* ψ(r)^* ψ(r)dr[/tex]

## The Attempt at a Solution

It is obvious to me that if

[tex] <m|\hat A|n> = <\hat A m|n>[/tex]

then

[tex] <m|\hat A|n> = <n|\hat A|m>^*[/tex]

My professor gave me a hint and said that I need to expand these out and show that they are equal. This is where my problem lies. I have no idea how to expand these out. I have tried a few ways, like setting

[tex]\phi _m = (\psi -c_n \phi _n)/c_m[/tex]

This certainly did not seem like the correct approach to me.

Maybe someone here can give me another hint as to how this goes. I have asked my professor three times to talk to me about it, but he seems content in misunderstanding me and talking about other problems that we have already solved.