# Need help with simple quantum problem

1. Mar 26, 2004

### einai

Hi, I came across a problem which seems to be pretty simple, but I'm stuck .

Given a Hamiltonian:
$$H=\frac{\vec{p}^2}{2m}+V(\vec{x})$$

If |E> is a bound state of the Hamiltonian with energy eigenvalue E, show that: $$<E| \vec{p} |E>=0$$

-----------------------------------
So I've been trying something like this:

$$\frac{1}{2m}<E|\vec{p} \cdot \vec{p}|E> + <E|V(\vec{x})|E> = E<E|E> = E$$

but I have no idea how to proceed from here. I don't think I'm on the right track actually.

Thanks in advance!

Last edited: Mar 27, 2004
2. Mar 27, 2004

### Staff: Mentor

FYI: This question has been answered in the quantum physics forum.

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?