Momentum in QM

[pardesi]

what does the momentum in de broglie wavelength signify?
i mean how do u defien it...we can define the expectation in momentum but how do we define momentum for "quantum mechanincal" particles

[Vanadium 50]

Same as you do classically.

[malawi_glenn]

For a first exposure:

http://en.wikipedia.org/wiki/Momentum#Momentum_in_quantum_mechanics

Can show you why this is later if you want, it is related to translation in space - momentum is the generator of translation.