Why do we need a photon to mediate the electromagnetic force?

[LorentzR]

I apologize for entering the thread so late, I don't mean to comment on the previous discussions, just comment this line...
What would you say is the difference between a measurement process and interaction process in general? Aren't measurements effectively an interaction where the outcome yields new information? Human measurements are specially designed and controlled interactions. But hardly of any other principal "nature" than say two particles interacting? Or, what would the pricipal difference be?

Assuming the idea of symmetry between observation and interaction, the idea of reality beeing independent from measurements seems to suggest that this reality would be in a different universe, since it is also independent of interactions? Which would suggest that this type of reality have no connection to the universe we live in?

IMO, something that lives it's own life, independent of interactions with me(x) lacks justification for me(x). My personal thinking is that the qualifying justifications is the interactions, because what else is there? This is still a little fuzzy, but I'm not sure how much clearer it'll get.

/Fredrik

I suspect that quantum systems continuously interact with the rest of the universe and are fully connected to the universe we live in.

In order for an observation to be made the effect of an interaction must be amplified into a detectable event. Then there must be somebody there to observer the event.

For a “particle” to have physical reality it must have a universe to interact with and be able to reference the magnitude of its physical states.

 

[LorentzR]

What are you saying about the relationship of physical to quantum? They do have a loose relationship in that one models the other.

We do not have a wholly reductionistic theory modelling one with the other. We depend on the Born rule for quantum mechaics to work.

I don't understand how the quantum object is "separate and independent" from observable results. The quantum object predicts the results, although this doesn't imply unity between object and result.

Quantum mechanics predicts the results.

 

[XVX]

I’m particular interested in the Pseudo-Riemann manifold where the contracted Riemann-Christoffel tensor vanishes. This is the event arena of general relativity where the geometry is locally modeled on the Minkowski metric.

Accepting the validity of relativity then a four-fold Riemann space-time must be rejected as the event arena for the physical world. We are left with the Pseudo-Riemannian Space-time.

My question is how does the photon (and the graviton) fit into such an event arena.

My feeling is, historically, these particles were initially invented to explain action at distance at a time when the geometry world was falsely thought to be Riemannian in nature. Riemannian Geometry being locally modeled on Euclid.

There is no metric for the Universe. And certainly, the perihelion of Mercury was not calculated with the Minkowski metric. And unquestionably, GPS systems do not use the Minkowski metric. The Minkowski metric is GR’s special case in which one has Newton’s Laws and a finite speed limit theory that is commonly known as, SR.


But why photons?

Why does matter choose energy in packets?

When EM waves are incident upon Hydrogen, is there some mechanism in Hydrogen that says, “we will wait a time ‘t’ dependent upon wave amplitude, to collect ‘E’ energy and then decide what to do with it.”?

Or does energy come in packets?

I picture particles like billiard balls surround by a potential barrier. When a photon hits Hydrogen, the photon can either, get over the barrier and be absorbed into the center or there is just a collision with the outer barriers. An EM wave of high energy, but low frequency has a bunch of balls, but individually, they are weak and none can penetrate the absorption barrier. These are photons. These are the packets of energy that bombard a target. The target is not bombarded by some solid piece of energy that the target chooses whether to take a bite out of or not and how big the bite should be. I see no contradictions with the photon, GR and Minkowski space.

QM showed this interaction with matter and quantized energy and QED was just the next step in saying, well, if EM waves are made of photons, then what about the rest of E&M? And QED has been tremendously successful, although, its greatest triumph of the anomalous magnetic dipole moment of the electron is not nearly as good for the muon.

And trying the same strategy to understand gravity in a similar way and make us believe in a graviton has been a failure. While I don’t believe in the graviton, GR reigns supreme here, Einstein was unable to formulate an EM theory with “his” strategy. And QM reigns supreme here.

As of today, IMO, the photon is the explanation for the EM forces and GR is the explanation for the gravitational force.

BTW, one step in disproving the photon would be to give a new model for the photoelectric effect………….just...for starters.

 

[Anonym]

And unquestionably, GPS systems do not use the Minkowski metric.

?

To the best of my knowledge, they do. I have no reference handy, but all algorithms (iterations, Kalmans, etc.) are based on the Minkowski interval.

Regards, Dany.

 

[cristo]

?

To the best of my knowledge, they do. I have no reference handy, but all algorithms (iterations, Kalmans, etc.) are based on the Minkowski interval.

Regards, Dany.

GPS systems involve satellites orbitting a massive body (the earth) and thus must use general relativity somewhere. In fact, GPS uses both special and general relativity. Check out this paper for more info: http://relativity.livingreviews.org/Articles/lrr-2003-1/

 

[LorentzR]

There is no metric for the Universe. And certainly, the perihelion of Mercury was not calculated with the Minkowski metric. And unquestionably, GPS systems do not use the Minkowski metric. The Minkowski metric is GR’s special case in which one has Newton’s Laws and a finite speed limit theory that is commonly known as, SR.

.

I was trying to make the distinction between Riemann space and Pseudo Riemann space.

The former is locally modeled on Euclid and the latter, as used in GR, locally modeled on Minkowski.

The metric in a gravitaional field is Schwarzschild's

 

[Anonym]

In fact, GPS uses both special and general relativity.

Thank you. Your statement is obviously correct:

“Hence, the principle of the constancy of c finds application as the fundamental concept on which the GPS is based.

Therefore, to implement Eqs. (1 ), the receiver must generally perform a different rotation for each measurement made, into some common inertial frame, so that Eqs. (1 ) apply.

For the GPS it means that synchronization of the entire system of ground-based and orbiting atomic clocks is performed in the local inertial frame, or ECI coordinate system [6].” Etc.

I refer to XVX:” There is no metric for the Universe. And certainly, the perihelion of Mercury was not calculated with the Minkowski metric. And unquestionably, GPS systems do not use the Minkowski metric. The Minkowski metric is GR’s special case in which one has Newton’s Laws and a finite speed limit theory that is commonly known as, SR.”

I am at holydays now and can’t check about Mercury. I am sure that he is wrong about it too. His statements I consider absurd.

Regards, Dany.

 

[cristo]

I am at holydays now and can’t check about Mercury. I am sure that he is wrong about it too. His statements I consider absurd.

What, particularly, about his statements are absurd? There is no "metric for the universe," since GR is a local theory.

The solution to the precission of the perehilion of Mercury was one of the great successes of GR. This certainly does not use the flat spacetime metric, but instead uses the Schwarzschild metric. You can see this derivation is many GR textbooks if you are not convinced!

 

[Mentz114]

There is a metric for the universe. It's called the Friedman-Lemaitre-Robertson-Walker metric. See any book on cosmology.

 

[Anonym]

There is no "metric for the universe," since GR is a local theory.

Perhaps I did not understand him properly. Tomorrow I will prepare the answer as needed.

Regards, Dany.

 

[lightarrow]

I picture particles like billiard balls surround by a potential barrier. When a photon hits Hydrogen, the photon can either, get over the barrier and be absorbed into the center or there is just a collision with the outer barriers. An EM wave of high energy, but low frequency has a bunch of balls, but individually, they are weak and none can penetrate the absorption barrier. These are photons. These are the packets of energy that bombard a target. The target is not bombarded by some solid piece of energy that the target chooses whether to take a bite out of or not and how big the bite should be. I see no contradictions with the photon, GR and Minkowski space...

So, which are photon's dimensions? If they existed, would they be independent of its energy? If a photon is a particle, how is its wavefunction related with the existence of that particle in a specific point of space? Is the wavefunction THE particle?

I sincerely cannot understand how you can so easily give real existence to mathematical objects.

Yes, QED has been proved up to a very high degree. Does it mean we should believe in the existence of "energy packets" flying from source to detector? Maybe; but maybe someone could, one day, describe the same results with a different theory.

Certainly, it's not the case to reject a theory that works so well! But I'm not saying this. What I mean is that I can't understand how can low energy photons exist from source A to detector B if you cannot detect them (because you destroy them in doing it).

 

[cristo]

There is a metric for the universe. It's called the Friedman-Lemaitre-Robertson-Walker metric. See any book on cosmology.

Of course, the FRW metric is as close to a model of the visible universe that we have. However, my point was that GR is a local theory, with local curvature. For example, the FRW metric would not describe the metric outside, say, a massive star. In retrospect, my point didn't really answetr the question!

Anyway, this has gotten rather off topic-- I've just noticed that this is a thread in the QP forum!

 

[ZapperZ]

So, which are photon's dimensions? If they existed, would they be independent of its energy? If a photon is a particle, how is its wavefunction related with the existence of that particle in a specific point of space? Is the wavefunction THE particle?

I sincerely cannot understand how you can so easily give real existence to mathematical objects.

Can you show me evidence in history where we actually give in THAT easily? May I remind you how much resistance the Einstein's photoelectric effect model had when it was first introduced? Should I point out to you Millikan's highly skeptical paper on it when he set out to literally falsify it? Where is this "easy" part? I want to know!

So you also have issues with the whole of classical E&M? After all, it IS nothing more than a set of "mathematical objects"? I don't see you complaining about this in the classical physics section whenever classical E&M is discussed. The energy band gap in your semiconductor is also a relic of some mathematical objects. Yet, you freely use it in your electronics.

If such a picture doesn't exist, then show me an alternative explanation to the experimental observations that I have mentioned, which, btw, NO ONE has attempted to tackle. Show me a non-photon formulation of the anti-bunching phenomenon and we'll talk. Yet, all we get are nothing more than objections due to a matter of TASTES! This is not physics and this has never been a valid argument against anything in physics.

Zz.

 

[George Jones]

?

To the best of my knowledge, they do. I have no reference handy, but all algorithms (iterations, Kalmans, etc.) are based on the Minkowski interval.

Regards, Dany.

Like cristo, I don't see how GPS calculations can be done solely with the Minkowski metric. Here's a simplified (but still quite accurate) https://www.physicsforums.com/showpost.php?p=731738&postcount=5" that uses the Schwarzschild metric and some Newtonian approximations.

 

[Anonym]

Like cristo, I don't see how GPS calculations can be done solely with the Minkowski metric.

Come on, guys! The original statement was:

And unquestionably, GPS systems do not use the Minkowski metric.

“A man ought to read just as inclination leads him; for what he reads as a task will do him little good." I find it strange that I know to read English better than you!

Thanks for the refs. Few years ago I was involved in the engineering projects connected with GPS.

Regards, Dany.

 

[George Jones]

Come on, guys! The original statement was:

Yes, and you responded

all algorithms (iterations, Kalmans, etc.) are based on the Minkowski interval.

To me, this seems to say that no other spacetime intervals are needed. Apparently, this is not what what you meant. Phrases like "all are based on" and "all are based soley on" are sometimes used interchangeably.

“A man ought to read just as inclination leads him; for what he reads as a task will do him little good." I find it strange that I know to read English better than you!

A bit of a cheap shot. Too easy.

 

[vanesch]

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.

I guess this comes about because when a useful theoretical concept becomes so familiar that we use it all the time, we give it some kind of "physical reality" status. Like you give "physical reality" status to the earth, the moon, your sister etc... Nevertheless, all these are nothing else but "theoretical concepts" which you use in your (intuitive) way of explaining your perceptions. "your sister" is nothing else but a theoretical concept you have that explains a lot of your perceptions (for instance, when you think that you "see your sister"). You cannot even set up "an experiment which would prove the physical reality of your sister" if you think deeply about it.
It's true that some concepts are closer to our intuition than others, so we are less eager to put its status of "physical reality" to doubt. The further away are those concepts from things that look like our "daily reality" (whatever that may mean for a relativist :-), the easier we put them in doubt.

I'm fully with ZapperZ when he says that science is just a way of putting together conceptual (theoretical) frameworks which "explain observations". Some of these frameworks are more suggestive of "physical reality" than others, simply because some are closer to the intuitive grasp we have of what we always assumed to be "part of physical reality" than others.

So what doesn't matter is the ontological question ("is it part of physical reality"), but rather the epistemological part, which determines what we can ultimately know about our perceptions - measurements - observations.

 

[lightarrow]

Can you show me evidence in history where we actually give in THAT easily? May I remind you how much resistance the Einstein's photoelectric effect model had when it was first introduced? Should I point out to you Millikan's highly skeptical paper on it when he set out to literally falsify it? Where is this "easy" part? I want to know!

So you also have issues with the whole of classical E&M? After all, it IS nothing more than a set of "mathematical objects"? I don't see you complaining about this in the classical physics section whenever classical E&M is discussed. The energy band gap in your semiconductor is also a relic of some mathematical objects. Yet, you freely use it in your electronics.

If such a picture doesn't exist, then show me an alternative explanation to the experimental observations that I have mentioned, which, btw, NO ONE has attempted to tackle. Show me a non-photon formulation of the anti-bunching phenomenon and we'll talk. Yet, all we get are nothing more than objections due to a matter of TASTES! This is not physics and this has never been a valid argument against anything in physics

Ok, but after those times (debates between Millikan and Einstein ecc.), the existence of photons was quite well established. I have never found teachers at university or physics books where someone had any doubt in it.
Certainly there has always been someone who had, but I didn't have knowledge of it.

One day, about 20 years ago, reading an article on Scientific American, I started asking myself about what a photon could actually be. At university, they couldn't say much more than "quantum of EM field". I felt as being the only one to have confused ideas, everyone else didn't seem to bother at all, students and teachers.

And now, after more than 20 years, for the first time, I know, from you, about the existence of another effect, the "antibunching effect", and (from a short search on internet) about how this "established incontrovertibly, and for the first time with visible light, that Einstein's particle picture of light could predict and explain something that a pure wave picture never could".

Incredible! This is the demonstration of the fact that I have always been totally right in having doubts about photons, despite the fact Everyone (and books) had always told me I was Completelly Wrong, mostly because of Blackbody Radiation, Photoelectric Effect, Compton Effect and everything it's written about it in every physics book!

Thank you very much, ZapperZ, you made me happy today!

Regards.

 

[Anonym]

A bit of a cheap shot. Too easy.

Believe me, even my mother tongue Russian I don’t know as required. But phrases like "all are based on" and "all are based solely on" are almost orthogonal for me since here my math background speaking.

Regards, Dany.

 

[Anonym]

"A man ought to read just as inclination leads him”.

Indeed, I present my own inclination only. The story began with:

I’m particular interested in the Pseudo-Riemann manifold where the contracted Riemann-Christoffel tensor vanishes. This is the event arena of general relativity where the geometry is locally modeled on the Minkowski metric.

Accepting the validity of relativity then a four-fold Riemann space-time must be rejected as the event arena for the physical world. We are left with the Pseudo-Riemannian Space-time.

I consider that as obviously correct statement. The second paragraph is perhaps only matter of experience. The physicists use to treat math not as a lady, but as a prostitute (for the very substantial reasons). They call Pseudo-Riemannian (Lobachevski) Space-time the Riemann space-time since to everybody clear that underlined event arena is 4-dim Minkowski. Those that seriously consider otherwise are not physicists.

Now come:

There is no metric for the Universe. And certainly, the perihelion of Mercury was not calculated with the Minkowski metric. And unquestionably, GPS systems do not use the Minkowski metric. The Minkowski metric is GR’s special case in which one has Newton’s Laws and a finite speed limit theory that is commonly known as, SR.

And now I have problem with English. What he mean “special”? If he mean “special” =“unique” than I misinterpreted him, but than it does not fit the spirit of the text above. If he mean particular among the others, nothing really special, than it is not even wrong:

L.D. Landau, E.M. Lif****z, Field Theory:”Theory of gravitation fields, founded on the SR, is called General Theory of Relativity.”

My question is how does the photon (and the graviton) fit into such an event arena.

My feeling is, historically, these particles were initially invented to explain action at distance at a time when the geometry world was falsely thought to be Riemannian in nature. Riemannian Geometry being locally modeled on Euclid.

Clearly, LorentzR is familiar neither relativistic QM nor QED nor with the history of QT.

Regards, Dany.

P.S. Sorry, our software have funny problem with E.M.

 

[LorentzR]

"A man ought to read just as inclination leads him”.

Indeed, I present my own inclination only. The story began with:
I consider that as obviously correct statement. The second paragraph is perhaps only matter of experience. The physicists use to treat math not as a lady, but as a prostitute (for the very substantial reasons). They call Pseudo-Riemannian (Lobachevski) Space-time the Riemann space-time since to everybody clear that underlined event arena is 4-dim Minkowski. Those that seriously consider otherwise are not physicists.

The Riemann metric signature is positive definite, Schwarzschild and Minkowski metrics are (p,1), hence they are not Riemannian.

Clearly, LorentzR is familiar neither relativistic QM nor QED nor with the history of QT.

Then you must have the answer to my question please enlighten me.

 

[Anonym]

The Riemann metric signature is positive definite, Schwarzschild and Minkowski metrics are (p,1), hence they are not Riemannian.

Apparently, you do not read what I wrote. In addition, Schwarzschild and Minkowski space-time are 4-dim with the signature {+,-,-,-} which is the consequence that the underlined algebraic structure is defined by 4-dim quadratic normal division algebra of the Hamilton quaternions.

Then you must have the answer to my question please enlighten me.

I already together with Zz gave you the answer: If you intend to do physics, study it.

Regards, Dany.

P.S. And try to justify your pseudonym.

 

[pmb_phy]

Because mediating it with pasta would seem awkward?

- Warren

Comments like this sever more to distract the reader rather than help solve the actual problem.

Pmb

 

[XVX]

I meant to come out swinging and show that the Minkowski metric is one “event arena” for GR, not the sole one. Thus, him claiming GR is irrelevant and therefore the photon doesn’t exist.

?

I didn’t think I was making bold statements with my examples and I didn’t mean to imply the Minkowski metric has no use, just that it is……clearly…..not the only one used.

That was the GR statements goal. Perhaps some better statements would have been:

“There is no one metric for the GR events in the Universe.”

"And unquestionably, GPS systems do not use JUST the Minkowski metric."

And I have no comment on Mercury.

Reimann manifold, pseudo-Reimann manifold, non-Euclidian geometry, Minkowski space. Why do we choose what we do?

http://en.wikipedia.org/wiki/Tests_of_general_relativity



Why the photon?

Ya know, there are people to this day that still resist QM. I can only imagine the nuttyness that people must have thought when it was first being introduced as “reality.” But what changed? The idea of “calling something” an electron, a photon? The particle picture of light came before the wave picture. QM is what made physicists say, whoa, this light particle stuff is serious business, we better call it something.

And the photon will always be. Just like Newtonian physics will always be, but not like how the Thompson Model turned out. As time progress’s, we learn more about, “what we call a photon” and our picture of it may change, but that thing called a photon will still remain. Hey, someday the photon may be a vibrating string and we will then say, that string with that mode corresponds to……….a photon.


In type II superconductors, some call the penetration of flux lines, fluxons and treat them as particles. There is a quanta of flux. While I admit that calling these flux tubes particles is a stretch of the definition, it doesn't change the fact that this quanta of flux exists. Whether it's a particle can be debated.
In general,
Doubting what people call "fluxons" means you doubt that there is a quanta of flux.

Doubting what people call "photons" means you doubt that there is a quanta of EM energy.

If QM is just some lucky model that does so well in predicting our Universe, but its explanation of reality is totally wrong, then what a colossal misfortune.

I’m not a betting man, but I’m gunna have to go with…….QM has a lot of explanations that exist in reality. The negative seems to implausible.

With all the electronics surrounding me right now as I type on this incredible device called a computer, I cannot accept this all as luck or coincidence. If I did, then I would be a physicist that believes in absolutely nothing. My only belief being, coincidence dominates.

But at some point, we have to use inductive reasoning.

 

[cristo]

“There is no one metric for the GR events in the Universe.”

Hey, I'm glad it's not just me, then. That's the point I thought you were trying to make!

 

[lightarrow]

Why the photon?

Ya know, there are people to this day that still resist QM. I can only imagine the nuttyness that people must have thought when it was first being introduced as “reality.” But what changed? The idea of “calling something” an electron, a photon? The particle picture of light came before the wave picture. QM is what made physicists say, whoa, this light particle stuff is serious business, we better call it something.

And the photon will always be. Just like Newtonian physics will always be, but not like how the Thompson Model turned out. As time progress’s, we learn more about, “what we call a photon” and our picture of it may change, but that thing called a photon will still remain. Hey, someday the photon may be a vibrating string and we will then say, that string with that mode corresponds to……….a photon.

In type II superconductors, some call the penetration of flux lines, fluxons and treat them as particles. There is a quanta of flux. While I admit that calling these flux tubes particles is a stretch of the definition, it doesn't change the fact that this quanta of flux exists. Whether it's a particle can be debated.
In general,
Doubting what people call "fluxons" means you doubt that there is a quanta of flux.

Doubting what people call "photons" means you doubt that there is a quanta of EM energy.

If QM is just some lucky model that does so well in predicting our Universe, but its explanation of reality is totally wrong, then what a colossal misfortune.

I’m not a betting man, but I’m gunna have to go with…….QM has a lot of explanations that exist in reality. The negative seems to implausible.

With all the electronics surrounding me right now as I type on this incredible device called a computer, I cannot accept this all as luck or coincidence. If I did, then I would be a physicist that believes in absolutely nothing. My only belief being, coincidence dominates.

But at some point, we have to use inductive reasoning.

Ok, I agree on everything that you said. But:
Let's assume we don't know that light can be thought of as electromagnetic waves, but we know how its made of energy packets (photons) and how to relate different colours to different energies of these packets. We make experiments with coherent light (light which packets have a well defined energy, measured for example through photoelectric effect, ecc.) and we discover how, making light go trough slits on a screen, we find regular fringes on a distant screen. We find rules that relates the fringes spacings to the distance between the slits, the distance between the two screens and the energy of the packets (light's colour).

Then, someone come in and ask: but, why all this happens?
And all people could say: "physics it's not about <<why things happens>>, but how it works. We have our rules, they are physics principles, things happens in this way, and that's all".

Then, one day, someone else comes, and say: wait a moment! But, if light is a wave, then everything it's explained much better in this way...

So, maybe QM (and QED) is the best we can know about light, or maybe one day...

(Why E = hv?).

 

[reilly]

As has happened before on this topic, there is here much ado about nothing. Common sense, and sophisticated physics knowledge cannot answer whether or not there is an objective reality, let alone a real photon. The point is that the idea of a photon turns out to be a powerful and practical concept--you pays your money and takes your chances.

Philosophers and their kin want more than descriptions -- well, go to it, beat us dirt-farmer physicists at our own game. Do something that brings new data or experiments to the table, something that conventional physics cannot duplicate. Some folks for years have been criticizing QM as lacking this that or the other thing -- talk is cheap, and the anti-QM
stuff has lead to no new physics over that last 50 years or so.

Regards,
Reilly Atkinson

PS How could you prove the existence of "objective reality"

 

[Fra]

Having little to do with the photon, but in defence of all the philosophers out there... :)

Philosophers and their kin want more than descriptions

Physics and philosophy has a common history and from my limited history knowledge some of the QM founders was still quite philosophical, which does not contradict with simultaneous formal rigor. They didn't have all the answers but they did acknowledge several deep questions, which is important. If you skip the question and jump right into manipulating formalisms with rigor, IMO the real point is missed.

Not all philosophers are into old style realism. That's perhaps one branch of philosophers, but beeing a philosopher doesn't mean your necessarily some conservative realist thinking that beneath there is a hidden universal structure that would maintain the old ideals.

Sometimes it's claimed that you need no philosophy in physics, because experiment will tell us right from wrong and "why it's right" is metaphysics. You just learn howto apply the theory, and produce the predictions.

But I think that is an oversimplification, which even hides the most important step. First of all the confidence in any real experiment is always finite. So the confidence in any piece of evidence is also finite. Right or wrong, needs to be replaced with more or less confidence in something.

Second comparing a prediction with experiment and conclude that they either disagree or not seems very trivial.

The non-trivial part of this interaction is howto update your predictions in response to conflicting information. The no-philosophy arguments seems to trivialize the only truly non-trivial step.

Yes, I want more than a description. I want a description of howto evolve my description when I'm wrong. The cases when I am right is trivial and doesn't teach me much. Obviously the "minimum intelligence" evolution is to just scramble everything up and you come up with a new random model you can test in a experiment with rigor. But we all know we can do far better than that.

PS How could you prove the existence of "objective reality"

I consider myself philosophical (though I don't study philosophy as such), but I do not think there is any sensible objective reality in the classical sense. And it is not a problem.

One of my current issues with physics is that it seems a bit amgious. That doesn't means it's wrong. It just means that it's hard to see the coherent line of reasoning. This has bugged me since high school. Some people, who are differently minded seems minimally disturbed by this. But this philosophical think makes progress. I've made a lot of progress for myself, and I attribute a lot of it to the fact that I never allowed myself to ignore the important questions because they were fuzzy.

Perhaps the experimentalists may consider the theorists as a black box, to which they report results, and expect out in the other end an update predictive model. And they design new tests to test the updated model. Even a group coming up with random theories should be able to make progress, but it would be far less efficient than if the black box had more intelligence. Thus there seems to be something that determines the efficienct of this black box? what? can we learn more about this?

I am interested to know exactly how the black box works, in as much as I like to know how a particle "works".

I have a feeling that sometimes the underlying tone of reasoning is that it doesn't matter how this box works, the important parts is that whatever comes out of it, is confirmed or not confirmed by experiment.

But what happens in the case of rejection? the theory was wrong, then what? shouldn't the nature of the rejection infere the best correction?

I want to see the essence of reasoning, built into our models. This is currently missing. The scientific method and the models (output of the scientific method) should implement a feedback, until the scientific method is unified with the models.

/Fredrik

 

[Fra]

talk is cheap

Indeed, also in the litteral sense. If you don't get payed to do research, perhaps the cheap way is the only way So let's hope we've invested our taxmoney on the right horse. For a fair comparasion, perhaps the results should be weighted with the investments made in each approach?

/Fredrik

 

[LorentzR]

And the photon will always be. Just like Newtonian physics will always be
.

I can’t agree with this logic since Newtonian physics is a working paradigm which successfully makes predictions about observations on macroscopic events, given an initial set of conditions. Newtonian physics is permanently integrated into our culture.

On the other hand the photon is a literal convenience associated with experiments whose outcome lacks full deductive explanation. Until such a time as a deductive explanation becomes available any description should be regarded as provisional and treated with the utmost caution.

We already have had to discard the aether as the mediator of light, the failure of the idea of the photon to give non-contradictory properties to the phenomenon of light suggests it too might have limited life expectancy.

But at some point, we have to use inductive reasoning.

Unthought-of possibilities will catch out those who abandon deductive logic.

 

[LorentzR]

Apparently, you do not read what I wrote. In addition, Schwarzschild and Minkowski space-time are 4-dim with the signature {+,-,-,-} which is the consequence that the underlined algebraic structure is defined by 4-dim quadratic normal division algebra of the Hamilton quaternions.

I was simply pointing out the that the metric signature was not (+, +, +, +) required by Riemannian geometry. Sorry if I missed your reference.

I already together with Zz gave you the answer: If you intend to do physics, study it.

Regards, Dany.

P.S. And try to justify your pseudonym.

If a concept is not sustained by deductive reasoning, no matter how long you study it the fundamental weaknesses will remain.

Relativity and quantum mechanics are well validated, the photon is not, and there is nothing currently in human knowledge that fully supports the possibility it has any form of physical reality.

The photon's true status is metaphysical, even though it seems to be accepted by popular culture as intrinsically real.

 

[lightarrow]

As has happened before on this topic, there is here much ado about nothing. Common sense, and sophisticated physics knowledge cannot answer whether or not there is an objective reality, let alone a real photon. The point is that the idea of a photon turns out to be a powerful and practical concept--you pays your money and takes your chances.

I have no doubt about it. Even the concept of heat as a material substance was useful (probably less than the concept of photon), but now we don't use it any longer. If, instead, one day it will result a sligth non-zero rest mass for the photon, I would have much less doubts on that cocept.

Philosophers and their kin want more than descriptions -- well, go to it, beat us dirt-farmer physicists at our own game. Do something that brings new data or experiments to the table, something that conventional physics cannot duplicate. Some folks for years have been criticizing QM as lacking this that or the other thing -- talk is cheap, and the anti-QM
stuff has lead to no new physics over that last 50 years or so.

Regards,
Reilly Atkinson

PS How could you prove the existence of "objective reality"

Measuring it.

This is what makes the difference between physics and philosophy.
A low-energy photon, considered as a "flying particle" is more a philosophycal concept than a physical one.

 

[bruce2g]

...
PS How could you prove the existence of "objective reality"

...
Measuring it.

This is what makes the difference between physics and philosophy.
A low-energy photon, considered as a "flying particle" is more a philosophycal concept than a physical one.

I have thought about this also, and I've come to ask the following question: "does the photon exist before it is detected?" There's a lot of thought behind this question -- can you examine other events to see if a photon has been created, or can there be any evidence of its existence before it interacts with a detector? I think the electromagnetic field strength indicates the probability that a photon might be detected, but I also think that a photon's "existence" is a just another quantum property that cannot be measured until it is detected -- i.e., when its wave function collapses. So personally, I don't think it "exists" before it is detected.

(Incidentally, I apologize for jumping in so late in the discussion, but I've wanted to ask this question for a long time, and I like the way lightarrow thinks (I too am impressed by the anti-bunching evidence)).

So, if you guys aren't sick of this question already, I'd like to divide the original question into two: does a photon exist before its wave function collapses (i.e., before it's detected), and does it exist when it is detected?

 

[vanesch]

So, if you guys aren't sick of this question already, I'd like to divide the original question into two: does a photon exist before its wave function collapses (i.e., before it's detected), and does it exist when it is detected?

... And does the detector exist when you look at it and when you don't ?

You see, "measure it" will ultimately always come down to a kind of subjective perception, at which point you will have to make in any case a *hypothesis* of the ontological existence of something. As such, you can argue endlessly over the (non) existence of theoretical concepts such as photons, electrons, voltmeters and sisters. In the end, it is always a matter of hypothesis. But, as Reilly pointed out so correctly, that's not the point. The point is NOT whether the "photon ultimately exists". The point is that the photon is a very practical theoretical concept which helps us "visualise" and explain a lot of observations. In the same way perhaps, as your sister is.

 

[Fra]

In despite of my defense of the "philosophy", I roughly agree with both reily and vanesch, but I disagree a little tiny bit on one focus point.

But, as Reilly pointed out so correctly, that's not the point. The point is NOT whether the "photon ultimately exists".

I agree completely.

The point is that the photon is a very practical theoretical concept which helps us "visualise" and explain a lot of observations.

I sense that the ambition to get a practical concept, is too modest. I mean, relative to what? Relative to the worst case, anything is more practical.

I want to the extent possible the _most practical_ concept, and the missing measure is the one quantifying "practical". There sure is a point where one would think that ANY randomly chose concept IS the most practical one, because getting stuck in mindloops trying to decide what the next step is, isn't practical either. But I think there should be a balance between the two extremes, yielding some "optimal strategy" to progress. So that our ambition should not just be to make progress, because making progress is almost unavoidable. I think the ambition should be to make the most efficient progress allowed by the limitations at hand.

So, some kind of minimum philosophy of the scientific method is IMO not completely out of place.

This also implies a fundamental level of humbleness as to save us from thinking that we "proove things" when we in fact are just guessing. I think the difference between a scientific guess and a random guess is that the scientific guess is the supposedly the BEST guess, but that's not to mistake it for the "truth", or to tink that the supposedly best guess, in fact IS the best guess.

So we are as it seems just learning by guessing... by then, so why don't we construct our theories in the honest way that is designed for it's scientific evolutionary purpose? That's the future physics I want to see on the table.

/Fredrik