Independent virtual particle after mind experiment annihilation

[NoelyG]

Independent virtual particle after "mind experiment" annihilation

Hello good people,

Probably a bit of a silly question, but I have been entertaining a bit of a thought experiment about the following. Consider the following:

1. A virtual photon is exchanged between two electrons to mediate the electro-magnetic force.
2. The photon can only travel at the speed of light, so during its travel time, one electron is completely annihilated
3. Does the virtual photon still exist, or wouldn't it have been emitted in the first place?

Probably a silly question, but if any of you could shed some light on this it would be greatly appreciated. Thanks!

 

[cosmik debris]

You are confusing a real photon with a virtual photon. Virtual photons are mathematical artifacts which are not limited to any speed or energy, we refer to this as being off mass shell. If a real photon is emitted it exists until it is re-absorbed.

 

[NoelyG]

Thanks for the reply cosmik,

I guess what I was curious about was the following:

1. The electro-magnetic force can not be "communicated" faster than the speed of light
2. We have two electrons separated by a distance x
3. If one electron "pops" out of existence at time t, will the other electron still feel a repulsive force for x/c?

You say that virtual photons, which, mathematically at least, communicate the electro-magnetic force but are not limited in speed or energy - however, if this is the case, why is it that the electro-magnetic force is only communicated at the speed of light?

Sorry if these are silly questions, I am no doubt missing something fundamental. Thanks for your assistance.

EDIT: Am I correct in saying that the electro-magnetic force is communicated via virtual photons (i.e. unobservable) rather than real photons (observable)?

 

[cosmik debris]

You have to be careful when you talk about EM. The case where the field is static is different from the case when EM waves are emitted. The energy in a static field is carried by virtual photons. The energy in EM waves are carried by real photons. In the static case there is nothing to propagate the field is just there as it has always been, that's why it is called static. When a charge is accelerated it will emit EM waves which are comprised of real photons which propagate at c.

Your thought experiment violates the rules, an electron cannot pop out of existence, that would violate conservation of energy and charge, if you break the rules predictions cannot be made.

 

[NoelyG]

Thanks for taking the time to educate me cosmik, makes sense now

 

[rajendrakumar]

The said statements are not silly, If we thought without violating any of the physics laws for example the bulb of 60 watt will realize one photon in priscribed time.