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LorentzR
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A simple question but one I personnaly find difficult.
Why do we need a photon to mediate the electromagnetic force?
Why do we need a photon to mediate the electromagnetic force?
:rofl: :rofl:chroot said:Because mediating it with pasta would seem awkward?
- Warren
chroot said:Because mediating it with pasta would seem awkward?
- Warren
LorentzR said:My reason for asking this question was that four fold manifolds seem to come in two varieties.
Riemann and Pseudo-Riemann
The observed properties of light gives contradictory characteristics for Riemann geometry.
And the photon seems an unnecessary requirement in pseudo-Riemann geometry.
It just seems an idea founded historical convenience?
Pasta would do the job equally well and a least spaghetti is consistent with string theory.
Milind_shyani said:Welcome to the forums
Now i don't know whether you are talking about topological manifold or a smooth manifold. But see photon is an elementary particle now the definition itself says that it is elementary.
Now if we put your logic in physics than there would be various discrepancies.for eg graviton is a virtual paritcle than what's the use of having it and so on...
I hope that i have not misunderstood your queation.
Why do we need a photon to mediate the electromagnetic force?
...And the photon seems an unnecessary requirement in pseudo-Riemann geometry.
It just seems an idea founded historical convenience?
Mentz114 said:Only if you quantise the EM field do you need a mediating boson. The photon is not a requirement in classical electrodynamics.
In which case spaghetti hoops are probably most appropriate.
I don't understand. There is a debate about whether photons exist in the way other fundamental particles do. Some people will say they don't exist at all. It is a somewhat fuzzy area.You are not addressing my question of; why the mediator of electromagnetism should have an existence independent of other quantum mechanical systems?
LorentzR said:I don’t think you have any choice in the matter; classical electrodynamics cannot describe the behaviour of the atom.
You are not addressing my question of; why the mediator of electromagnetism should have an existence independent of other quantum mechanical systems?
ZapperZ said:This is a very strange question. It's like asking "why does an object needs a force to make it move or accelerate?".
Zz.
Newton’s laws of motion are a set of rules used as the basis of a methodology which we use to make predictions about the motion of objects relative to a given reference system.(Given the ability to measure the location of objects relative to the reference grid). What underlies the nature of a force is unknown.ZapperZ said:In QFT, you START with such field, the same way you make those 3 Newton Laws of motion. From there, you verify that they are correct based on observation.Zz.
ZapperZ said:Now as for having "an existence independent of other quantum mechanical systems", I have no idea what you mean by this considering that the quantum field is a "quantum mechanical system".
Zz.
LorentzR said:In general relativity there is no gravitational force, objects just follow geodesic paths through pseudo Riemannian space-time.
Newton’s laws of motion are a set of rules used as the basis of a methodology which we use to make predictions about the motion of objects relative to a given reference system.(Given the ability to measure the location of objects relative to the reference grid). What underlies the nature of a force is unknown.
In quantum mechanics the methodology is modified by the Born rule so that the probable outcomes (observable macroscopic effects) of experimental set-ups involving quantum entities can be predicted.
Again the concept of a quantum field is an object used in our methodology, whether or not it has any physical reality is unknown and the assumption that it is a quantum mechanical system is perhaps premature.
ZapperZ said:I know of a theorist here in our division that said the same thing about OTHER theorists (argue with the experimentalist is waste of time).
LorentzR said:In general relativity there is no gravitational force, objects just follow geodesic paths through pseudo Riemannian space-time.
Newton’s laws of motion are a set of rules used as the basis of a methodology which we use to make predictions about the motion of objects relative to a given reference system.(Given the ability to measure the location of objects relative to the reference grid). What underlies the nature of a force is unknown.
In quantum mechanics the methodology is modified by the Born rule so that the probable outcomes (observable macroscopic effects) of experimental set-ups involving quantum entities can be predicted.
Again the concept of a quantum field is an object used in our methodology, whether or not it has any physical reality is unknown and the assumption that it is a quantum mechanical system is perhaps premature.
ZapperZ said:It HAS a physical reality - the experimental observations (and there's tons of them) indicate that to be so. Why are people ignoring that fact?
Anonym said:Zz, come on! Not everyone that visits PF is a physicist.
ZapperZ said:Can you dumb down the rules a little bit more here so that we can move this over to the philosophy forum?
Anonym said:No. I think the rules are fine, just what they are supposed to be. It should be some kind of the dynamical equilibrium, otherwise or we move over to the philosophy forum or will remain alone.
I think peoples are not in general ignoring the experiment, they don’t know that it exists and substitute the objective knowledge by subjective imagination. In addition, we have the moderators which are the control feedback loop to maintain the system alive.
ZapperZ said:But was exactly what I was doing, as a Moderator - pointing out experimental evidence that has been ignored in all of this. You somehow think that not being a physicist is a valid excuse for not considering it. I don't buy that.
The whole existence of PF that distinguishes it from the gazillion other physics forums IS the higher standards and quality that we asked for in these discussions. Pointing out the obvious omission of experimental observations, in my look, is crucial because it is what distinguishes physics from philosophy.
ZapperZ said:For some odd reason, you are allowing and even excusing such an omission
ZapperZ said:It HAS a physical reality - the experimental observations (and there's tons of them) indicate that to be so. Why are people ignoring that fact? Is empirical observation THAT despised and irrelevant?
Zz.
LorentzR said:Pardon my scepticism but I find it difficult to visualise any experiment that can prove the existence of the photon.
You were the one that said the "photon HAS a physical reality."ZapperZ said:Actually, you have a twisted way of understand what science does, especially physics. You don't prove anything in physics. There are no proofs for Newton's laws, or anything that you have accepted. There are a SET of experimental observations that are consistent with a theoretical description. That's it! This then allows us to make a conclusion that that theoretical description WORKS and is valid within the range that we know of. It is why we can tell your electronics will work! I hate to blow your bubble, but you have had a faulty understanding of how science works.
If you think that there's another theoretical explanation for the which-way experiment and the photon anti-bunching experiment other than using the photon picture, I'd like to hear it. Till then, this is all just empty speculation.
Zz.
LorentzR said:You were the one that said the "photon HAS a physical reality."
I was just pointing out you can't prove that. I think your above comments suggest you would not normally have made such bold statement.
ZapperZ said:But I QUALIFY by what I mean by that! I just didn't throw it out without explanation.
You, on the other hand, made no definition of what you mean by "physical reality". Why? Do you not think that using an example of what you consider to have a "physical reality" would be useful? Or do you think that when you make such an illustration, it could easily be shot down?
Zz.
Reshma said:LorentzR,
I think you might want to read this thead:
https://www.physicsforums.com/showthread.php?t=155091
LorentzR said:I suppose by physical reality I mean the object possesses states separate from and independent of the measurement process.
Empirical data clearly is dependent on the measuring process. And quantum mechanics is designed to predict the probable outcomes of the measurement process for a given experimental set-up. Quantum mechanics is not a complete reductionistic theory so there is no fully deterministic linkage between the outcome of the experiment and the quantum processes determining the outcome of the experiment.
If a reductionistic theory is possible and that theory included the photon as one of its elements then balance of probabilities would swing towards the photon having physical reality.
In the meantime we have a working methodology that makes no attempt to indicate whether its elements possesses physical reality; and to date attempts to create a reductionistic theory has demanded the elementary components of our theory to have contradictory characteristics.
ZapperZ said:Then you do not have a problem with "the photon", but rather with quantum mechanics, the most successful theory every produced in all of human civilization to date. You have a problem with the electrons, protons, neutrons, modern electronics, MRI, etc... etc..., not just "the photon".
Zz.
LorentzR said:I don’t have a problem with quantum mechanics since it is only concerned with the observable outcome of experimental situations.
But I do have a problem with the attribution of physical states to the above list of quantum objects which is separate and independent from the observable macroscopic response of the detectors in the experiment; which is fundamentally different issue to the validity of quantum mechanics.
LorentzR said:But I do have a problem with the attribution of physical states to the above list of quantum objects which is separate and independent from the observable macroscopic response of the detectors in the experiment; which is fundamentally different issue to the validity of quantum mechanics.
ZapperZ said:No, it isn't. That's the whole issue behind EPR-type experiments! You are arguing about what Bell identified as "realism".
Zz.
LorentzR said:I suppose by physical reality I mean the object possesses states separate from and independent of the measurement process.
Sorry I can’t agree.ZapperZ said:No, it isn't.
Zz.
ZapperZ said:That's the whole issue behind EPR-type experiments! You are arguing about what Bell identified as "realism". It has nothing to do with those particles, but rather with how QM describes those particles. You are also mixing your "personal tastes" into this, which has never been a valid argument against anything in physics. It is why I asked for experimental observations in the very first place. If not, we might as well argue about our favorite colors.
Zz.
I absolutely agree with ZapperZ's comments on proofs and physics. But his assertion that the Photon has a physical reality is inconsistent with his comments on proofs.reilly said:LorentzR --You would do well to study Mandel and Wolf's Optical Coherence and Quantum Optics.Virtually anything you want to know about photons is covered. Photons are old hat because they are an extremely useful and powerful concept; really no different from the concept of time, or force, or... We and our ancestors made all this stuff up; ZapperZ is dead on target about proofs and physics.
reilly said:How would you design an experiment to determine the reality of a photon?
Regards,
Reilly Atkinson