Photon Size: Direction & Probability

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Discussion Overview

The discussion revolves around the nature of photons, specifically addressing questions about their directionality upon emission, the concept of photon size, and how they can be detected. Participants explore theoretical implications, experimental observations, and the interpretations of quantum mechanics related to these topics.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants inquire whether photons emitted from sources such as antennas or excited atoms travel in all directions or if there is a probability distribution for their direction.
  • There is a suggestion that the question of photon size is poorly phrased, as photons do not have mass and their "size" may not be a meaningful concept in traditional terms.
  • One participant argues that the detection of photons depends on the configuration of antennas, suggesting that the effective area for detection can change based on the arrangement of wires, which raises questions about the "size" of photons.
  • Another participant emphasizes that photons should be treated as pointlike particles, while also acknowledging the wave-like behavior observed in experiments such as the double-slit experiment.
  • Some participants express confusion over the relationship between the wave function's wavelength and the concept of particle size, with differing views on whether photons can be considered pointlike or if they exhibit a size based on their wave properties.
  • There are references to the dual nature of photons and how this duality complicates the understanding of their behavior and properties.
  • One participant notes that the question of photon size often arises in discussions, suggesting a need for clearer explanations in educational materials.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the nature of photons, their size, or the implications of their wave-particle duality. Multiple competing views are presented, and the discussion remains unresolved regarding the fundamental questions posed.

Contextual Notes

Participants highlight limitations in the phrasing of questions and the assumptions underlying discussions about photon properties. The discussion reflects varying interpretations of quantum mechanics and the challenges in conceptualizing the behavior of photons.

  • #61
marlon said:
The observation of ANY phenomenon at the atomic scale follows this procedure, YES. Otherwise, the HUP would be violated. But how is all of this related to the "topic of discussion in this thread" ?
Because of what you wrote about "indirect observation" of a photon. I think there is only a "direct observation" in that case. So, since answering to my question "where is then the photon?" you wrote that "Only when you measure with the detector, you will observe the photon indirectly", I deduce the photon doesn't exist before the measure.
 
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  • #62
marlon said:
I mean that whenever we "observe" a photon or an electron, we observe the result of the interaction of that photon/electron with the apparatus (for example emitted EM radiation etc etc).

marlon

Yes, I agree with you. But the reality may rejects your claim. Of course it satisfys me.:smile:

Thanks.
Mr Beh
 
  • #63
lightarrow said:
Because of what you wrote about "indirect observation" of a photon. I think there is only a "direct observation" in that case. So, since answering to my question "where is then the photon?" you wrote that "Only when you measure with the detector, you will observe the photon indirectly", I deduce the photon doesn't exist before the measure.

That deduction is incorrect, obviously. We know "there is a photon" but we have no information on its position prior to ANY measurement.

I am glad we cleared that out.

regards
marlon
 
  • #64
Anonym said:
Zz, come on! You are very experienced manipulator and you even can’t imagine how I enjoy reading your posts!



To the best of my knowledge, that question (definition) and it possible connection with the advanced and retarded solutions of Maxwell eqs. was the content of R.P. Feynman Ph.D. study. The obtained results allowed him as continuation of the research to formulate QED.



As I explained in my post #22, the size of photon may be measured macroscopically by defining the diameter of the black body box.

Understanding of that point allowed to M. Planck and A. Einstein to start formulation of the Quantum Theory.

Later L. de Broglie demonstrated in his Ph.D. thesis that the same approach valid for the massive fields in general and for the electron in particular. That allowed to E.Schrödinger, W. Heisenberg and P.A.M. Dirac to complete the non-relativistic version of the Quantum Theory.



No. It is not my attitude here in QP of PF. I present here the superorthodox approach to the QT. What I say is written in every standard textbook on QT, except the M.Born statistical interpretation of QM. Only with respect to this point there is no general consensus inspite that there exist tons of experimental results that demonstrates that M.Born is wrong and E.Schrödinger and A. Einstein are right.

However, I do not believe that the QT may be studied through the Internet Forums, Wiki-Piki or Gogol-Mogol. I try to present the POV such that it will lead certain kids to go to the literature and to try understanding what is written there.



It is because the connection between the Quantum World and the Classical World is not fully established and fully understood yet. It is the Measurement Theory and the Measurement Problem (Schrödinger’s Cat: collapse of wave packet) all about.



I have no professional knowledge in details of the Particle Accelerators. You are the expert. I asked you question about the Inverse Schrödinger’s Cat. I need your help to know whether I am wrong or not. Please, answer my question (HUP and Particle Accelerators).

Regards, Dany.

P.S.

Fine! I am the one that provided the ultimate prediction that the proton is the QM ground state of three bounded quarks. It is the obvious result of my Ph.D. study entitled “Quantum Mechanics of Non-Abelian Waves”.

Honestly, I have no idea where this is going, or why protons and quarks would even come in here.

All I asked for is for the REFERENCE source for the size of a photon. So far, you haven't come up with it, and neither has Proof.Beh. Notice that *I* did no such claim (contrary to the problem that Proof.Beh has in reading what I wrote) to photons having ANY kind of size. All I asked for is, at the level where things ARE accepted, is there a definition for the size of a photon. That's it, nothing more, nothing less.

Not surprisingly, something as simple as that has been clouded over with tons of red herrings. So in case this isn't clear, let me reemphasize it again, especially for those who are trying to get some resemblance of a FACT out of this thread:

Standard references that physicists use have no definition for the "size of a photon", be it in terms of theoretical derivation such as those to arrive at the classical electron radius, or in terms of experimental measurement as that used to obtain values such as "e" and "h". Both the PDG and the CODATA handbooks have no such information.

Now, if one wants to go beyond that, fine. However, it is imperative that one first DEFINE it clearly, because it is obvious from what I just said that such a definition hasn't been established in the standard references. THIS is the point that I've been trying to get across! Not that photons are point particles, photons have the size of its "energy packets", photons have "coherence length", etc... etc.! For some odd reason, trying to get people to pin down the definition of what they're talking about somehow annoys the them! I don't get it.

Zz.
 
  • #65
Proof.Beh said:
Yes, I agree with you. But the reality may rejects your claim. Of course it satisfys me.:smile:

Thanks.
Mr Beh

Look, i am willing to continue this thread but if you are going to start posting hollow meaningless messages based upon your personal speculation, i assure you that measures will be taken. You are violating PF Guidelines. As i have told you before, speculation will NOT be tolerated. You can say ANYTHING you want but you need to back it up with serious evidence.

I tried to ask you questions on several occasions but you refuse to answer them. All you do now is bumb into a discussion i have with someone else and say "Hey , haha, you see, I AM RIGHT". C'mon man, do you really think this kind of childish communication has ANY influence what so ever ?

Continue in a serious way or this thread will be locked down !

Bye

marlon
 
  • #66
marlon said:
That deduction is incorrect, obviously. We know "there is a photon" but we have no information on its position prior to ANY measurement.

I am glad we cleared that out.

regards
marlon
We know by virtue of some *interpretation*, not because we can prove it.
 
  • #67
lightarrow said:
We know by virtue of some *interpretation*, not because we can prove it.

Look, i am not sure where you are going with this. I mean what does this have to do with the topic of this thread (photon size) ?

All i said was that when the electron hits the detector, you are not observing the electron itself but you are observing the result of the interaction between electron-detector. That is all.

Now, let's go back to the topic at hand, ok ?

marlon
 
  • #68
Proof.Beh said:
LoL. So again, I remember that there are no unique definition for describing existence of a photon size like that I said in my post #40. Therefor we don't derive a good CONCLUSION. Since we argue with our own knowladges. Also ,ZZ, you confess that you haven't a legitimate source to prove your claim that it is neither existence of photon size or rejection of it.

You have problems with reading and comprehension.

I have made no rejection. ALL I said has been explained in my post before this. The only claim I made was the definition of the size of a photon isn't listed in any of the standard references for elementary particles. That's it! Your inability to understand that somehow twisted it around to mean something that only exists in your head. I suggest you re-read, using more than just one translator program that you are using, of what I originally said.

And you shouldn't be asking for "legitimate sources" yourself, because you haven't provided any for practically everything you claim. I have listed the sources that I used to back my claim above. Have you done the same thing?

Zz.
 
  • #69
marlon said:
That deduction is incorrect, obviously. We know "there is a photon" but we have no information on its position prior to ANY measurement.

I am glad we cleared that out.

regards
marlon

Huh? What is your proposal about photon is there surely? You emphasized that if we assume that a photon has size, we must measure it. But in this case that a photon has no measurement property, then is it there?

Thanks.
Mr Beh
 
  • #70
Proof.Beh said:
But in this case that a photon has no measurement property, then is it there?

Thanks.
Mr Beh
The photon has no measurement property ? What on Earth does THAT mean ?

Mr Beh, when are you going to answer to my questions i asked you in post nr 50 ?

marlon
 
  • #71
Anonym said:
I know to read and I do not need your explanations yet. However, you did not understand what I wrote in post #24. Now you apparently wrote the same. You may compare in order to see that (you can’t understand only the second sentence; the content will be clear after I will publish the expected results).

Lack of the experience prevent your understanding of the physical content of jtbell beautiful demonstration that the suggestion is correct. You may understand much more reading Hans de Vries, post# 84 in “Very simple QFT questions”.

Regards, Dany.

The "jtbell beautiful demonstration" is not correct because he uses |psi|^2 instead of r^2|psi|^2.
 
  • #72
ZapperZ said:
All I asked for is for the REFERENCE source for the size of a photon.

L. Mandel and E. Wolf, “Optical coherence and quantum optics”, Cambridge Univ. Press, (1995).

ZapperZ said:
if this is true, then you need to ask yourself why, in all of these fat reference books

If you don’t want to read it, nobody force you. Proof.Beh wants. In addition, your requirement is equivalent to the question: What is the size of one litre of water?

Regards, Dany.

P.S. Notice that Shahin insists on the QM definition: The "jtbell beautiful demonstration" is not correct because he uses |psi|^2 instead of r^2|psi|^2.Good morning, Shahin!
 
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  • #73
Anonym said:
P.S. Notice that Shahin insists on the QM definition: The "jtbell beautiful demonstration" is not correct because he uses |psi|^2 instead of r^2|psi|^2.Good morning, Shahin!

Yes, yes, i repeat it again for you:

The "jtbell beautiful demonstration" is not correct because he uses |psi|^2 instead of r^2|psi|^2

Read carefully, maybe this time you will understand the meaning of this phrase.

Good morning?...here it´s 19:20 hours...
 
  • #74
Shahin said:
Yes, yes Good morning?...here it´s 19:20 hours...

NO NO NO NO. Don’t shoot him!

Good evening!

Regards, Dany.
 
  • #75
Anonym said:
L. Mandel and E. Wolf, “Optical coherence and quantum optics”, Cambridge Univ. Press, (1995).

I am quite sure, there is nothing about the size of photons in that book, but I do just have the 1973 version here at the moment. Could you please give me the page, chapter or an exact quotation of the passage you mean, so I can check, what you mean?

p.s.:
The "jtbell beautiful demonstration" is not correct because he uses |psi|^2 instead of r^2|psi|^2

I am afraid, this is going to become a running gag. :rolleyes:
 
  • #76
Anonym said:
L. Mandel and E. Wolf, “Optical coherence and quantum optics”, Cambridge Univ. Press, (1995).
If you don’t want to read it, nobody force you. Proof.Beh wants. In addition, your requirement is equivalent to the question: What is the size of one litre of water?

Oh, don't worry, I will read it, especially considering that if it is THAT well-established, how come NONE of the standard references use it.

And why is the requirement equivalent to that question? And why is there such hostility towards asking for something like this? And you wonder why I refuse to engage in the discussion in the other thread?

Zz.
 
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  • #77
ZapperZ said:
And you wonder why I refuse to engage in the discussion in the other thread?

Anonym: “What is the minimum charge of the bunch available?”

Anonym:” Zz, may you respect me also through your comment on “HUP and Particle Accelerators”?

I did not intent to engage you in the discussion since I am not qualified. In addition, I repeat: If you don’t want to answer, nobody forces you.

Regards, Dany.
 
  • #78
ZapperZ said:
I have listed the sources that I used to back my claim above.
Zz.

I wait to introduce your listed valid sources.

Thanks.
Mr Beh.
 
  • #79
Proof.Beh said:
I wait to introduce your listed valid sources.

Thanks.
Mr Beh.

Er... what did you think the PDG and CODATA handbooks are? If you notice, I cited the PDG handbook in my very first post in this thread. Did you not notice what it is?

I notice you still aren't able to list YOUR valid sources.

Zz.
 
  • #80
Our valid references:

"About The Photon Physical Properties". Reissig, Sergej. American Physical Society, APS March Meeting, March 21-25, 2005.

"On the Average Volume per Photon in Blackbody Radiation". Sherwin, Chalmers W. University of Illinois, Urbana, Illinois.

Thanks.
Mr Beh
 
  • #81
Shahin said:
The "jtbell beautiful demonstration" is not correct because he uses |psi|^2 instead of r^2|psi|^2.

For a properly normalized wave function, |\psi|^2 is the probability per unit volume, whereas r^2|\psi|^2 basically gives you the probability per unit radius. I personally consider |\psi|^2 to be more appropriate in this context. Note that if we (hypothetically) have a |\psi|^2 which is uniform everywhere inside a sphere (that is, the particle is equally likely to be found anywhere inside the sphere), then r^2|\psi|^2 increases as r^2, to a maximum at the surface of the sphere.

Nevertheless, granting that you prefer r^2|\psi|^2, let's evaluate your criterion for the ground state of hydrogen. I haven't found a way to do it algebraically, so I simply made a graph of r^2 e^{-2r/a_0}. The maximum is at r = a_0. Going inwards, I reach 0.1 of this maximum at about r = 0.013a_0, and going outwards, I reach the same value at about r = 3.4a_0. That's a bigger range of r than my original calculation using |\psi|^2! :eek:
 
  • #82
ZZ, why deleted my post #80? you insult many users in your posts and when we answer by dialect similar to your abusive dialect, you delete the our posts. I'm sorry really.
 
  • #83
Proof.Beh said:
"About The Photon Physical Properties". Reissig, Sergej. American Physical Society, APS March Meeting, March 21-25, 2005.

Sergej Reissig is a guy, who claims stuff, which is not at all accepted in the physics community. As far as I know, he has no up to date peer reviewed publications to offer.

In "About the nature of the photon" he states, that his photon model consists of a photon, which rotates around some axis and has a mass of approximately 10^{-36}kg. The actual experimental lower bound of photon mass is somewhere arond 10^{-48}kg, if I remember correctly. So that theory seems to be plain wrong. As a consequence, this is not really a reference, which should be trusted.
 
  • #84
Proof.Beh said:
Our valid references:

"About The Photon Physical Properties". Reissig, Sergej. American Physical Society, APS March Meeting, March 21-25, 2005.

Er.. this is not a valid, legitimate reference. The APS March meeting, which *I* have presented at many times, is a "contributed" session in which anyone can present a talk if you register. No one cites this. There's no proceedings. You only get "abstract" at most. Please cite a peer-reviewed published citation on par with a standard reference (you do know what that is, don't you?)

"On the Average Volume per Photon in Blackbody Radiation". Sherwin, Chalmers W. University of Illinois, Urbana, Illinois.

Er... what is this? You quoted a title, but gave no exact citation. Please look at a typical paper and see how the references are made.

You must also answer the question on why, if this is already "accepted", that it isn't part of the STANDARD references that physicists use!

Zz.
 
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  • #85
Proof.Beh said:
ZZ, why deleted my post #80? you insult many users in your posts and when we answer by dialect similar to your abusive dialect, you delete the our posts. I'm sorry really.

Where did I do such a thing? If you believe that I have, please REPORT the post. I deleted your post because (i) it had no content relevant to this thread and (ii) its intention was simply to incite. Because your of issues with understanding what you read and what you wrote, I did not send you infraction points even though from my judgment, you violated our guidelines.

However, if you repeat this, you will be penalized for it.

Zz.
 
  • #86
ZapperZ said:
Er... what did you think the PDG and CODATA handbooks are? If you notice, I cited the PDG handbook in my very first post

I did not see that implys a photon has no size in there. If you mean that because there is no SUGGESTION to photon size we must accept that a photon has no size, you are wrong. Again, if you have a valid source that implys a photon structure (size etc.), please introduce it.

ZapperZ said:
Where did I do such a thing? If you believe that I have, please REPORT the post. I deleted your post because (i) it had no content relevant to this thread and (ii) its intention was simply to incite. Because your of issues with understanding what you read and what you wrote, I did not send you infraction points even though from my judgment, you violated our guidelines.

But it related to this discussion that emphasized to argue with logical reasons and connected to valid sources statements. We (Anonym and me) introduced our sources though you did not confirm them.

Thanks.
Mr Beh
 
  • #87
Proof.Beh said:
I did not see that implys a photon has no size in there. If you mean that because there is no SUGGESTION to photon size we must accept that a photon has no size, you are wrong. Again, if you have a valid source that implys a photon structure (size etc.), please introduce it.

You have some problems here with understand what is going on. Here's another analogy of what is going on:

There is a difference between a set consisting of zero, i.e. {0}, and an EMPTY SET, i.e. {}.

The former means that the set consist of a value of zero. The latter means that there's nothing in it. Do you understand this?

Now, look at what I wrote IN THE VERY BEGINNING. I said that in the standard references (i.e. PDG book, CODATA, and CRD Handbook) there are NO DEFINITIONS, NO VALUES of something resembling the size of a photon. I made NO ASSERTION about the size of a photon. You did.

You have somehow confused my references to those sources as implying that *I* said that photons have no size. I will ask you to go read again, this time VERY carefully, what I have written, because I have said no such thing. I would never say such a thing because to me, that makes no sense.

You really need to read things more carefully, because you are getting all worked up for nothing, and chasing around things that don't exist. And I have presented my evidence. All you need to do is go get a copy of the PDG (available freely on the web), and prove me wrong by actually finding a definition of the size of a photon.

I also have a feeling that you are not aware of the significance and importance of the PDG handbook. Ask any particle/high energy physicist about it. You'll see for yourself.

But it related to this discussion that emphasized to argue with logical reasons and connected to valid sources statements. We (Anonym and me) introduced our sources though you did not confirm them.

Huh? And that is an "insult"? Your translator thingy isn't too accurate. Have you ever considered that?

You haven't introduced any. All you did was cite some dubious sources such as the APS march meeting (which you probably found by googling). APS March meeting are not valid references. How in the world are you able to know the content of the talk if you were there? You can't go by with the abstract because it isn't verified, and someone can easily change what they talk on when compared to the abstract. I know that *I* have done something like that that changes it slightly from the abstract that I submitted. Again, there's no proceedings to the March meetings. So you can't tell what was presented. Besides, no one use the March meeting as citations! So no, you haven't given any, and certainly not anywhere near the references sources of the caliber of PDG and CODATA.

Zz.
 
  • #88
In [1] the formula for the determination of the photon force was received:|F|=hcλ^(-2) (1). The pressure of the photon can be calculated according to the following formula [1]: P=F/A (2). In [2] the effective area of the photon was defined: A=Pi.λ^2 (3). By using the Eq.(1) together with Eq.(2) and (3) the following equation can be derived: P=[hcλ^4]/Pi or
P=const.λ^(-4)=6.3230521pt;10-26.λ^(-4) (Pa) (4). The thermodynamic analysis has shown that the equation -P_h.V_h=kT can be used by describing of the photon thermodynamic condition in such form P_p.V_p=hf (5). The use of the Eq. (4) and (5) makes the calculation of the photon volume Vp possible: V_p=hf/P_p = Pi.λ^3 (6). The new equations (5,6) were proved with one theoretical procedure: -dE / dE dt . - dt=-d(PV)p / dE / dE dt. -dt=-d(PV)p dt. -dt=hf^2 (7). Finally, it is possible to calculate the density of the light particle: V_ρ=m=h/cλ. cλ or ρ=const.λ^(-4)=0.703534;10^(-42).λ-4 [kg/m^3 ] (8). With the Eq. (4) and (8) one other pressure equitation can be expressed: P=ρc^2 (9). The multiplying the left and right sides of this formula on V by using the Eq. (5) delivers the famous, well-known Einstein formula E=mc^2. [1] Determination of the Photon Force and Pressure.

Abstract of descriptive methods in "About The Photon Physical Properties".

Thanks.
Mr Beh
 
  • #89
Proof.Beh said:
I did not see that implys a photon has no size in there. If you mean that because there is no SUGGESTION to photon size we must accept that a photon has no size, you are wrong. Again, if you have a valid source that implys a photon structure (size etc.), please introduce it.

I consider your suggestion to connect the presence of some structure with the size (which I consider pure geometrical notion) very interesting and I think you are right. Notice that you defined it locally. I mean vacuum indeed (+ something sometimes) and it seems to me that Zz mean the same, but I have no idea how it related to PDG book.

Regards, Dany.
 
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  • #90
ZapperZ said:
And why is there such hostility towards asking for something like this?

There is no any hostility. It is a question from psychology and it is outside physics. I don’t know why posts of jtbell, Hans de Vries, dextercioby, etc cause me pleasure and there are others that I simply don’t read. I consider that irrelevant. However, the related notion of “eigenschaften” I consider interesting and important. By the way, I finished all necessary calculations (from my individual POV) three month ago and don’t understand why I don’t write paper. Again, that I consider irrelevant.

ZapperZ said:
And why is the requirement equivalent to that question?

We already discussed that in “Particle-Wave duality and Hamilton-Jacobi equation“. Sorry, that I repeat:

Lightarrow:”I still don't know if and how would be possible to create a definition for an electron's size.”

You refuse to follow the standard rules of the scientific development. The notion of size was introduced by Egyptians, perhaps 7000 years ago. You take two points and stretch a cord. Then you ask what an angle is (firstly what is 90deg angle. It leads to the phenomenological result: 3^2+4^2=5^2 and to the corresponding theoretical generalization). It provides foundation for Euclidian geometry. That provides foundation for the mathematical formalism of metric spaces.
That provides foundation for Newtonian formalism. Later you introduce the communication problems. That provides the foundation of special and general relativity based on non-Euclidian geometry. And so on. In the non-relativistic QM it is well defined notion: the eigenvalues of the self-adjoint operator called dispersion of a position are measurable quantities. The mathematical formalism of relativistic QM is still open problem. You can discuss, but can’t require giving you definition of the size there. For sure, the answer to a question what is the size of an electron, quark or gluon a posteriori will be consistent with the Egyptians.

I consider anyone who deny that Don Kishot.

Regards, Dany.
 

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