# B Wave Particle Duality

1. Oct 29, 2016

### Naman Jain Kota

Hi, i am doing an introductory course in quantum mechanics (that would be equal to first two chapters in griffith's quantum mechanics).
I have the doubt that what exactly do we consider in quantum mechanics. Let me say like the electron is a particle and when we will observe it will have a defined position, and otherwise it may have been in superposition of various positions according to its probability wave. I guess thats the copenhagen interpratation.

But is that the way we speak of dual nature of matter, like the way we are taught de broglie's hypothesis we say if waves have dual nature particle may also have dual nature with the argument of Symmetry. But in that case I guess and i feel that the way we have dual nature in electromagnetic radiation, we must have dual nature of electron same way.
The wave associated with matter is only a probability wave.
That wasnt the way i thought about dual nature, it was somewhat like electron is a well particle at sometime and a wave at some time like photons or other way i.e. like photons also have some probability associated in form of wave and things like collapsing etc.
And more general i guess we must have fundamental equation applying both for radiation and matter, even if photons are mass less.

Please point out conceptual mistakes! and i know interpretation of quantum mechanics is a big job not so at basic level. Does quantum field theory have provide some solution to this wave particle problem.

2. Oct 30, 2016

### Simon Bridge

Wave particle duality does not exist.
The deBroglie stuff is of historical importance only.

The "wave" associated with a particle is a complex probability amplitude - the probability density function is this wave multiplied by it's complex conjugate. And no, that is not how you'd normally think about things: it's called "counter-intuitive" for a reason.

Last edited: Oct 30, 2016
3. Oct 30, 2016

### PeroK

If you were expecting Griffiths to explain the wave-particle duality, you will be disappointed. He mentions in the Afterword (Chapter 12, page 420, of the 2nd Edition) as a historical footnote.

4. Oct 30, 2016

### Staff: Mentor

Here is a much better view of exactly what QM is about:
http://www.scottaaronson.com/democritus/lec9.html

If your introductory course teacher wants to argue with an MIT professor - good luck.

Take my word fir it its a much better view than the semi-historical half truths promulgated in popularisation's and some introductory courses.

My view is the following is THE introductory textbook to get after a first course in general physics such as IB Physics HL or similar

Symmetry is the real deal rock bottom essence in physics but unfortunately usually only taught later at graduate school. The above corrects that oversight that has been around far far too long.

Then you can read Ballentine - QM and Landau Mechanics with ease and have a very though grasp of physics well and truly ready for really hard stuff like by Peskin and Schroeder althoigh I would do the following first:

Thanks
Bill

5. Oct 30, 2016

### vanhees71

Well, finally there's something good about Griffiths's QM book ;-)).