Virtual Particles

[Edtharan]

I'm not sure if this is the right place to post this, but it seemd the most apropreate.

 

A question that has been in my mind for some time now is: Can charged virtual particles curve in a magnetic field?

[RyanJ]

I'm not sure if this is the right place to post this' date=' but it seemd the most apropreate.

 

A question that has been in my mind for some time now is: Can charged virtual particles curve in a magnetic field?[/quote']

 

If you mean they are charged and asked if their paths wil change with the present of a magnetic field I think the answer is yes but this should probably have been posted in the Theoretical physics section where you'd have gotten a better answer

 

Cheers,

 

Ryan Jones

[Dave]

Moved to a better place, since it is a valid question after all

[Edtharan]

Thanks Dave.

 

Also on the same line:

Could a Virtual Positron Anhilate a Real Electron while at the same time promoting the partner virtual electron into a real electron (and there by returning the energy sum to 0)?

 

The effect I would assume is something like Quantum teleportation or Quantum Tunneling.

[5614]

I don't think a virtual particle can anihalate a real particle. And although it would be affected by a magnetic field I don't know if you could observe it.

 

But if a virtual positron and an electron anihalated each other that would produce a lot of energy. Any anihalation process produces a lot of energy. Due to this the energy sum would not be 0.

 

Neither quantum teleportation nor q tunneling are anything to do with this.

[Severian]

Both processes are allowed. Unless I am mistunderstanding you, the second process is a special case of the first. And the second case is one part of Compton scattering, which is a very well studied process. (I could draw you the Feynman diagrams if I were at work, but I am home right now. Maybe later...)

 

Maybe this might help:

http://www.wolframscience.com/nksonline/page-1060a-text?firstview=1

[Edtharan]

But if a virtual positron and an electron anihalated each other that would produce a lot of energy. Any anihalation process produces a lot of energy. Due to this the energy sum would not be 0.

 

I understand that particle/antiparticle anhialations do release energy, however in this case the virtual particles have "borrowed" energy and the anhialation of the virtual positron with the real electron would "pay back" the borrowed energy leaving the other virtual electron. Scine the energy needed to produce the virtual particles has been paid back the total enegy of the system is balanced (returned to the starting energy).

 

Of course this situation would only occure if the virtual positron could anhialate an electron. What I wnat to know is, could this situation occure?

[CanadaAotS]

I think severian just said it could...

[Severian]

Here are some graphs.

 

First, here is an example of a virtual electron interacting in a magnetic field:

 

 

and here is your second process, which is basically compton scattering:

 

 

(time is left to right)

[Edtharan]

Ok I understand the second picture,but the first is baffeling me a bit. Could you explain what is happening in it? Thanks.

[Severian]

OK. A photon (the wiggly line on the left) splits into an electron positron pair (the solide circle - remember time is left to right). The positron interacts with a magnetic field (the photons coming down - there needs to be two to conserve momentum) and finally the virtual electron-positron pair recombine back into a photon.

[Edtharan]

Ahh. Got it now.

 

What would happen if the positron in the first image encountered an electron and anihalated with it.

 

To make it clearer. The situation I am wondering about is a magnetic field perpendicular to the page (as in the first image) with two metal plates next to one another like this | |. the virtual electron/positron pair form between the plates and the magnetic field directs them to intercept each plate (the electron on one and the positron on the other).

[5614]

The situation I am wondering about is a magnetic field perpendicular to the page (as in the first image) with two metal plates next to one another like this | |. the virtual electron/positron pair form between the plates and the magnetic field directs them to intercept each plate (the electron on one and the positron on the other).

 

I'm bumping this thread as I would like an answer to Edtharan's question (quoted). Thanks to anyone who can answer it

[Meir Achuz]

"Originally Posted by Edtharan

The situation I am wondering about is a magnetic field perpendicular to the page (as in the first image) with two metal plates next to one another like this | |. the virtual electron/positron pair form between the plates and the magnetic field directs them to intercept each plate (the electron on one and the positron on the other). "

 

A magnetic field could affect virtual particles, but a virtual particle could not hit a plate. The VP (not Cheney) is a mathematical artifice that can only be part of an intermediate state. It can never be a final state particle.

[5614]

If a magnetic field could affect virtual particles then would it not be possible to split 2 virtual particles.

 

So photon comes along and splits into a virtual electron + virtual positron. The photon does not have enough energy to split in an electron/positron (real). And this all happens inside a magnetic field.

 

Due to the magnetic field the virtual particles are seperated.

 

Firstly what factor allows this to happen? Because normally to conserve energy the 2 virtual particles need to annihlate each other, if they are seperated they cannot annihlate.

 

Secondly if (due to this seperation) a virtual positron was on a collision course with a plate, what would happen?

[Severian]

What would happen if the positron in the first image encountered an electron and anihalated with it.

 

To make it clearer. The situation I am wondering about is a magnetic field perpendicular to the page (as in the first image) with two metal plates next to one another like this | |. the virtual electron/positron pair form between the plates and the magnetic field directs them to intercept each plate (the electron on one and the positron on the other).

 

This is then similar to the situation in the second diagram, just moving the initial state electron into the final state (making it a positron) and having it hit by another photon. The magnetic field is photons too, so you just produce the electron-positron pair and each interacts with a photon. In fact, this is the basis of electromagnetic colorimeters in particle physics detectors.

[Edtharan]

I have been thinking a bit more on this concept.

 

What if the plate are not parallel but are angled (eg \ /) or curved like the bell of a trobone?

 

If the magnetic field was adjusted so the the virtual particles could colide with the plates in one direction but not the other. Would this cause a tunneling like effect of electrons from mone plate to the other as the are anhilated on one side and the surviving electron from the virtual pair interacts with the other plate?

 

Would this then create a potential difference between the plates. this seems to produce energy from nothing, so where does the energy in the potential difference come from? (I think that the magnets would loose their charge some how due to the interaction of the magnetic fields created from the moving virtual particles - but I am probably wrong)