Some Quantum Mechanics That I dont understand

[ed84c]

There have been a number of issues raised in the learning of quantum mechanics that i am unsure of.

 

1. How can you explain electron spin in terms of waves?

 

2.How and when do photons interact with 'virtual' electrons in a vacuum?

 

3.How do photons interact when they are travelling away from each other i.e. at 2c

 

4.There is a way of describing electrons interacting with each other that means they travel back in time (this is deep QED) can anybody explain it to me?

 

5. I understand the purpose in QFD, but can somebody explain why is involves bosons, and more deep explaination?

[swansont]

I am not aware of an exlanation of spin in terms of waves, as it never seems to come up.

 

Speaking of photons moving apart at 2c presupposes that you are in the frame of one of the photons. It's not a valid reference frame.

 

The "interaction" is called entanglement, and has been discussed in other threads. Please read them.

[ed84c]

referance frame?

[Severian]

1. How can you explain electron spin in terms of waves?

 

If we restrict ourselves to spin-up and spin-down' date=' then the electron is not always in a definite spin-state. It could be a superposition of a spin-up state and a spin-down state, and only when you measure the spin does it 'choose' to be spin-up or spin-down. Since the composition of 'spin-upness' or 'spin-downness' can change, it has the properties of a wave.

 

2.How and when do photons interact with 'virtual' electrons in a vacuum?

 

All the time! A photon can turn into a 'virtual' electron-positron pair and then back into a photon.

 

3.How do photons interact when they are travelling away from each other i.e. at 2c

 

Swantson has already got this one.

 

4.There is a way of describing electrons interacting with each other that means they travel back in time (this is deep QED) can anybody explain it to me?

 

An electron travelling 'back in time' is just a positron travelling forward in time (this is a consequnce of the CPT theorem).

 

5. I understand the purpose in QFD, but can somebody explain why is involves bosons, and more deep explaination?

 

by 'QFD' I suppose you mean quantum flavor dynamics, as in the weak interaction? The bosons are the particles which transfer the force from one particle to another, called the W and Z bosons. Think of this like two iceskaters throwing a ball between them. In throwing the ball they exchange momentum and push each other away; they create a force by exchanging an object. There is nothing very mysterious about these particles - the humble photon is a bosonic force carrier for electromagnetism, so they are just generalisations of the photon.

[ed84c]

thankyou that has been invaluble