# De broglie wavelength for ordinary objects.

1. Oct 3, 2011

### Mike Anderson

Hello there,

If an object has a mass of 1 in arbitary units, and it's velocity is zero relative to you, what is the de Broglie wavelength? Shouldn't p be zero in this case? Or am I missing something related to intrinsic energy and momentum?

Thank you very much.

2. Oct 3, 2011

### DiracRules

well, I think the question doesn't even make sense.

It's more or less the same question as: you are travelling at the speed of light in front of a photon: what is its wavelength? You can't even see the photon (since you are travelling at its speed!), so you can't talk of it as something that affects you.

another example is : you pull an electron towards an obstacle. this obstacle moves at the same speed of the electron. What is the electron wavelength? Since the electron does not interfere with your system (the obstacle), it's no worth asking what is its de broglie wavelength.

What I'm trying to say is that, since in quantum mechanic it's the system that determines if you will see wavelike or particle-like behaviour, if your system doesn't allow the particle to interact in some way with it, it as if you are dealing with nothing.

3. Oct 3, 2011

### KWillets

p = 0 implies an infinite phase velocity and wavelength, relative to you.