[pensador (OP)]

If I am understanding QED correctly, which I suspect I am not.

A dielectric is an insulator that can be polarized by electric fields.

QED suggests the quantum vacuum can be polarized like a dielectric via virtual photons, and transmit forces such as electrical charge, momentum etc

https://en.wikipedia.org/wiki/QED_vacuum

I understand a real photon has no charge, whereas a virtual photon can transmit charges via polarizing the vacuum of space. Is it zero point energy that is being polarized or virtual particles modelled by the HUP or both.

Real photons maintain their properties from A to B. Virtual photons appear to lose intensity as their polarized field radiates from the source through the quantum vacuum. Is this correct?

Edit Perhaps not https://en.wikipedia.org/wiki/Vacuum_polarization
 
Virtual photons are considered off shell, are real photons on shell in that they can transfer momentum? 

[jeffreyH]

On shell and off shell relate to the equations of motion. On shell just means real particles that follow well behaved equations of motion. Off shell are the 'virtual' particle disturbances that have no well defined equations of motion.

See https://en.m.wikipedia.org/wiki/On_shell_and_off_shell

[pensador (OP)]

Electric fields have well defined distributions, that are transmitted by polarisation of the quantum vacuum. via virtual photons, which I think is a polarised field of virtual particles.
From your link
"
Virtual particles corresponding to internal propagators in a Feynman diagram are in general allowed to be off shell, but the amplitude for the process will diminish depending on how far off shell they are
"
Real Photons do not diminish in intensity..

In QFT, a photon is transmitted through the vacuum by ripping electron positron pairs from the vacuum. This is not the same as the method of propagation of virtual photons which polarize space around them ? Virtual photons and real photons appear to propagate differently albeit at c.

[jeffreyH]

Virtual particles are mathematical devices used in calculations. They preserve the conservation of energy and momentum. They are the invention of a mathematician. No more and no less.

[jeffreyH]

OK So say we have pair production from a photon of the energy required when reacting with a nucleus. We now have an electron and a positron. These are real particles. Say one fell into a black hole while the other escaped to infinity. This prevents an annihilation and the production of gamma ray photons. This is a pair of photons. Not just one.

So according to your scenario photons multiply as they propagate. They all end up as pairs of gamma rays. Which in turn generate more gamma rays.

I think you have something wrong.

[alancalverd]

In QFT, a photon is transmitted through the vacuum by ripping electron positron pairs from the vacuum.

I think not. You need at least 1.022 MeV to create an e-p pair.The photons I'm looking at right now are about 3 eV. 

[pensador (OP)]

In QFT, a photon is transmitted through the vacuum by ripping electron positron pairs from the vacuum.

I think not. You need at least 1.022 MeV to create an e-p pair.The photons I'm looking at right now are about 3 eV.

Yes, when I read this in my QFT book, it raised a question mark, hence the question above. Would it be more accurate to state that a photon rips/pulls/tares particle pairs from the vacuum with a size dependent on the energy of the photon.

In reverse a pair of particles colliding ie positron and electron become a pair of photons with 511eV. I dont think this  process can be reversed, but what happens as they pass through space? Are they pulling virtual particle pairs from the vacuum each with energy 255.5eV, and then returning it.

[pensador (OP)]

Virtual particles are mathematical devices used in calculations. They preserve the conservation of energy and momentum. They are the invention of a mathematician. No more and no less.

There is evidence they exist

[pensador (OP)]

So according to your scenario photons multiply as they propagate. They all end up as pairs of gamma rays. Which in turn generate more gamma rays.

No. according to QED the polarisation of the field spreads out as it passes through space, more photons are not generated. There is confusion between what is meant by virtual particles and virtual photons and real photons. A radio wave is made up of polarized virtual particles, as I read it. A Photon is not the same thing 

[The Spoon]

Virtual particles are mathematical devices used in calculations. They preserve the conservation of energy and momentum. They are the invention of a mathematician. No more and no less.

There is evidence they exist

Great. So if that is the case, you should present it to back up your statement.

[pensador (OP)]

Virtual particles are mathematical devices used in calculations. They preserve the conservation of energy and momentum. They are the invention of a mathematician. No more and no less.

There is evidence they exist

Great. So if that is the case, you should present it to back up your statement.

I guess you have heard of the following. Each one you will have to refute to back up your claim virtual particles do not exist in any form.

The Casimir effect > HUP > Zero point energy of the vacuum, QFT appears to rest on the virtual particles in the quantum vacuum of space, Hawking radiation relies on the existence virtual particles.

etc

Read the OP and try to keep your questions on thread

[The Spoon]

Virtual particles are mathematical devices used in calculations. They preserve the conservation of energy and momentum. They are the invention of a mathematician. No more and no less.

There is evidence they exist

Great. So if that is the case, you should present it to back up your statement.

I guess you have heard of the following. Each one you will have to refute to back up your claim virtual particles do not exist in any form.

The Casimir effect > HUP > Zero point energy of the vacuum, QFT appears to rest on the virtual particles in the quantum vacuum of space, Hawking radiation relies on the existence virtual particles.

etc

Read the OP and try to keep your questions on thread

You made a claim, the onus is on you to provide evidence.
Don't tell people what questions they can ask.

[pensador (OP)]

Virtual particles are mathematical devices used in calculations. They preserve the conservation of energy and momentum. They are the invention of a mathematician. No more and no less.

There is evidence they exist

Great. So if that is the case, you should present it to back up your statement.

I guess you have heard of the following. Each one you will have to refute to back up your claim virtual particles do not exist in any form.

The Casimir effect > HUP > Zero point energy of the vacuum, QFT appears to rest on the virtual particles in the quantum vacuum of space, Hawking radiation relies on the existence virtual particles.

etc

Read the OP and try to keep your questions on thread

You made a claim, the onus is on you to provide evidence.
Don't tell people what questions they can ask.

Evidence provided, go and look it up
I note you never answer questions. Your posts are meaningless
Go and start your own thread to ask questions if you have any. 

[The Spoon]

Virtual particles are mathematical devices used in calculations. They preserve the conservation of energy and momentum. They are the invention of a mathematician. No more and no less.

There is evidence they exist

Great. So if that is the case, you should present it to back up your statement.

I guess you have heard of the following. Each one you will have to refute to back up your claim virtual particles do not exist in any form.

The Casimir effect > HUP > Zero point energy of the vacuum, QFT appears to rest on the virtual particles in the quantum vacuum of space, Hawking radiation relies on the existence virtual particles.

etc

Read the OP and try to keep your questions on thread

You made a claim, the onus is on you to provide evidence.
Don't tell people what questions they can ask.

Evidence provided, go and look it up
I note you never answer questions. Your posts are meaningless
Go and start your own thread to ask questions if you have any. 

No it isn't. If you make a claim it is not up to other people to search out evidence. My posts are very clear. They are a response to you making a claim and not providing evidence that you claim is there.
You do not get to ask people to start their own thread - this is a public forum and your response is that of a petulant child.

[jeffreyH]

@flummoxed Look, take a deep breath, then go and chill for a while. Then you may have a clearer head.

[jeffreyH]

Now some food for thought. From here https://www.physicsforums.com/insights/misconceptions-virtual-particles/

"States involving virtual particles cannot be created since quantum field theory has creation operators only for observable particles whose 4-momentum satisfies the mass-shell constraint. For lack of a state, virtual particles have none of the usual physical characteristics of real particles: They cannot be said to exist in space and time, have no position, no meaningful probabilities to be created or destroyed anywhere, no life-time, cannot cause anything, interact with anything or affect anything. Therefore there is also no dynamics, speed of motion, or world lines. (In physics, dynamics is always tied to states and an equation of motion. Neither exists for virtual particles.)"

That sums it up in a nutshell, or off-shell if you prefer. If you wish to argue otherwise feel free to but in new theories.

[pensador (OP)]

Now some food for thought. From here https://www.physicsforums.com/insights/misconceptions-virtual-particles/

"States involving virtual particles cannot be created since quantum field theory has creation operators only for observable particles whose 4-momentum satisfies the mass-shell constraint. For lack of a state, virtual particles have none of the usual physical characteristics of real particles: They cannot be said to exist in space and time, have no position, no meaningful probabilities to be created or destroyed anywhere, no life-time, cannot cause anything, interact with anything or affect anything. Therefore there is also no dynamics, speed of motion, or world lines. (In physics, dynamics is always tied to states and an equation of motion. Neither exists for virtual particles.)"

That sums it up in a nutshell, or off-shell if you prefer. If you wish to argue otherwise feel free to but in new theories.

Feynmans virtual photons are just mathematical simplifications of field interactions, for peasants, which I think I realized already.

I am correct in concluding that Feynmans virtual particles do not exist in reality, and are not the same virtual particles as those predicted to exist in space by Casimir via calculations based on the uncertainty principle, supported experimentally. Giving rise to various quantum foam/gravity theories.

Further more virtual particle pairs borrowing there energy from the quantum vacuum of space momentarily, are nothing to do with QFT, other than they both use the term virtual particles.

Virtual photons are only something from QFT which do not exist in reality, and have never experimentally being proven to exist, as was claimed by someone on a earlier thread on this forum. An electromagnetic field is transmitted via polarizing space the quantum vacuum, around an antennae, not unlike written in my QFT book. A photon is a real packet of energy with no polarity.

Adding further to my confusion I googled for a link on evidence for the Casimir effect experiment which I know exists, and stumbled across this link https://www.scientificamerican.com/article/are-virtual-particles-rea/ Which leads me to think perhaps the terminology used by different Quantum theories leads to further confusion.

Am I correct in thinking the different Quantum theories use terms virtual particles differently.

 

[jeffreyH]

We can review another section of the page I posted.

"As discussed in detail in the companion article, virtual particles are defined as (intuitive imagery for) internal lines in a Feynman diagram."

These internal lines are only valid as part of the interaction they describe.

From your Sci Am page.

"Quantum mechanics allows, and indeed requires, temporary violations of conservation of energy, so one particle can become a pair of heavier particles (the so-called virtual particles), which quickly rejoin into the original particle as if they had never been there. "

The most important line is "as if they had never been there."

It is so easy to overlook the subtleties.

[jeffreyH]

NOTE: Now we are having a rational conversation. Isn't that better than a confrontation?

[alancalverd]

Are they pulling virtual particle pairs from the vacuum each with energy 255.5eV, and then returning it.

Seems a very complicated way of moving compared with either a particle-projectile or an electromagnetic wave model, and not entirely compatible with observation.