Virtual bosons and conservation of energy

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Discussion Overview

The discussion centers around the nature of virtual particles, specifically virtual photons, and their implications for conservation of energy and momentum. Participants explore the concept of virtual particles in quantum mechanics, their role in particle interactions, and related philosophical questions about fluctuations in the vacuum, such as Boltzmann brains.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Mark questions whether the absorption of a virtual photon makes it real, potentially violating conservation of energy.
  • Some participants suggest that energy is transferred as momentum, and that this does not imply virtual particles become real.
  • There is a discussion about the implications of momentum transfer from virtual particles to real particles and the potential for unlimited energy, which some participants challenge.
  • Another participant introduces a related question about Boltzmann brains and the nature of fluctuations in the vacuum, questioning the feasibility of such occurrences.
  • Responses indicate that momentum conservation applies to all interactions, and that energy and momentum are conserved universally.

Areas of Agreement / Disagreement

Participants express differing views on the implications of virtual particles and their relationship to conservation laws. There is no consensus on whether the absorption of virtual particles affects their status as "real" or the conservation of energy.

Contextual Notes

Participants acknowledge the uncertainty principle in relation to virtual particles, but the discussion does not resolve the implications of this principle on energy transfer or the nature of virtual particles.

Who May Find This Useful

Readers interested in quantum mechanics, particle physics, and philosophical implications of theoretical physics may find this discussion relevant.

a dull boy
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I read this on a website called Physics for Idiots

"If an electron gets near another electron it emits a virtual photon which is absorbed by the second electron and let's it know it need to move away."


If a virtual photon is absorbed, doesn't than make it real, and so break conservation of energy?

Thanks, Mark
 
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a dull boy said:
If a virtual photon is absorbed, doesn't than make it real, and so break conservation of energy?

The energy is transferred as momentum, according to wiki:
we can imagine one particle emitting a virtual particle which is absorbed by the other. The virtual particle transfers momentum from one particle to the other.

More here: en.wikipedia.org/wiki/Force_carrier#Forces_from_the_particle_viewpoint
 
If the energy is transferred as momentum, wouldn't that make the virtual particle real? Meaning, if a virtual particle can exist only within the uncertainty principle, and before it disappears transfers momentum to a real particle, where does that momentum come from?

I would think this could be a source of unlimited energy, if you could freely transfer momentum from virtual particles to real particles.

I must be missing something...

Thanks, Mark
 
the momentum the one particle gets is equal to the momentum the other particle is losing...
 
a dull boy said:
If the energy is transferred as momentum, wouldn't that make the virtual particle real?
No. Why should it?
Meaning, if a virtual particle can exist only within the uncertainty principle, and before it disappears transfers momentum to a real particle, where does that momentum come from?
Momentum is conserved at every interaction point.

I would think this could be a source of unlimited energy, if you could freely transfer momentum from virtual particles to real particles.
No. Energy and momentum are exactly conserved everywhere.
 
Actually I have related question; why do cosmologists worry about things like Boltzmann brains and so on? Isn't the idea there that "observers" could fluctuate out of the vacuum (given almost infinite time) and so with an infinity of universes or some such we would have to worry about the probability that we could be such observers?

But how does that make sense? Even granted that the vacuum could fluctuate into such a configuration, as stated above this would only be "allowed" for a completely negligible time interval, no matter how long we are allowed to wait for fluctuations. Am I missing something here?
 
Actually I have related question; why do cosmologists worry about things like Boltzmann brains and so on?
It would be weird to be one. And there is no reason why a Boltzmann brain should have a memory that looks like the world would follow any specific rules - this would be a very rare coincidence.
Even granted that the vacuum could fluctuate into such a configuration, as stated above this would only be "allowed" for a completely negligible time interval, no matter how long we are allowed to wait for fluctuations.
Still long enough to wonder about the world. This is very rare, but it could exist.
 

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