I have the following question about wave-particle duality:
Are particles really just waves with short wavelengths?
If this is correct, would it then be accurate to say:
"everything in the universe is a wave, but when a wavelength is short, it acts like our macroscopic conception of a particle. However, on a quantum level, everything is really just a wave"
For years, I have thought about it like I stated above and it makes perfect sense to me. Indeed, the de-Broglie relation
$$\text{wavelength} = \frac{h}{mv}$$
shows that all matter exhibits wave like properties seems to confirm my understanding that they are "really" just waves with short wavelengths.
But I ask the question because I hear quotes like "we don't know if things are particles or waves" and "our brains can't comprehend it", etc. I want to make sure I am not missing something.
The following quote also seems to justify the interpretation I have given above:
"If the distance between wave peaks is much smaller than the size of an object, the object will block the waves. But if the distance between wave peaks is much larger than the size an object, the waves will go around the object."
Thus anytime we use the word "particle" really it would be a wave with a very short wavelength given by the DeBroglie formula.
Any input would be appreciated.
Best Answer
Well, one can argue that there is no duality what so ever but that all particles are simply excitations of some quantum fields. For example, I do not think that it makes sense to say things like "an electron is both a wave and a particle at once" since after all it is neither classical wave nor classical particle but an excitation of the electron field and that's it.
The idea of wave particle duality is still useful though. It simply has to be used with more care. For example it makes sense to say:
"Under certain conditions, electrons may create interference patterns that are similar to the patterns observable for classical waves."
or
"Under other conditions, electrons can be scattered by a target and behave just like classical point particles."
The argument about the wave length etc. that you are making is a statement about the energy scales of the specific situation at hand. This energy scale determines which - if any - classical analogon (i.e. wave or particle) comes closest to the behaviour of your quantum system.