# Momentum Representation

1. Jul 23, 2009

### Geezer

For some reason, the momentum representation in QM wasn't covered in our class, so I'm figuring it out on my own (no, this isn't homework...it's just me reviewing physics for the PGRE).

My question: what is the energy (kinetic energy, I guess) of a particle in the momentum representation of QM? Obviously, p^2/2m is the usual KE, so is that the energy operator, too, in the momentum representation?

Thanks, y'all.

2. Jul 23, 2009

### maverick_starstrider

Yes, that's the KE operator, if there's a potential you'd have to write it interms of the momentum operator. $\hat{p}^2|p>=p^2|p>$