Is Planck's constant the key to understanding a quantum?

[trogan]

I repeat my recent comment - you are headed towards crackpottery at a million miles an hour. You're a QM novice. Nothing wrong with that; we all were at one time. But now you're now telling other people that they are doing it wrong and/or don't understand it. You really need to base this kinds of judgments on expertise, and you haven't put the effort into developing this expertise.

I highly recommend Steve Dutch's essay on http://www.uwgb.edu/dutchs/PSEUDOSC/SelfApptdExp.htm"





Exactly.



"Sit! Beg! Roll Over! Play Dead!"

You might think about using a little friendlier language than barking orders at the rest of the membership. It might put people in a better mood for replying.

I'm trying not to close this thread - but thus far, it's virtually entirely about unfounded hypotheses (and I have had to remove a number of messages). Please everyone, take a look at the PF Rules on overly speculative posts.

I am not exactly a novice. Well-informed amateur would be a better way of putting it. I have had an interest in QP for years and I am also an industrial chemist (prior to software development). Apart from a speculation about protons being the basis of matter I was under the impression that what I was saying was just mainstream QP. Noone has been taking issue with what I have been saying (at least with specifics) so I have been encouraged to keep going. I do have as my bible a book "Quantum Reality" by Nick Stevens which gives an eye-opening explanation of the quantum.

Please, if you have issues with what I am saying, tell me specifically. This is my purpose in being on PF.

As far as "Sit! Beg! Roll Over! Play Dead!" is concerned, I will take what you say on board and try and come across in a more friendly fashion. I certainly don't intend to be unfriendly and I REALLY appreciate the people on PF who are helping me. One of the problems I have is I sometimes don't know the expertise level of people I am replying to and thus can gear
my reply accordingly. I suspect this is a problem for many people.

It might be presumptuous of me to say this but I really do believe that what I have been saying is mainstream QP and if you don't agree then I would love to hear why.

 

[trogan]

I highly recommend Steve Dutch's essay on http://www.uwgb.edu/dutchs/PSEUDOSC/SelfApptdExp.htm"

I have read Steve Dutch's essay and agree with what he says - even if he does set himself up as a an expert on Self-Appointed Experts without, it would seem, psychology qualifications (insane grin ... can't get one on drop down). I do think he needs to chill somewhat ! I will try to phrase my posts accordingly - and chill, of course.

 

[ZapperZ]

Apart from a speculation about protons being the basis of matter I was under the impression that what I was saying was just mainstream QP.

So which part of "mainstream QP" did you get this from?

There is a difference between wanting to learn, and pretending that one knows enough to respond to a post as if one is giving a standard, acceptable answer. I can only guess that you know the difference between the two and can see that you, in fact, have done the latter. If you want to learn something, ASK. If you are not an expert in a particular subject, try to refrain yourself from offering an answer and defer to those who are. Providing a confusing, and often wrong answer is NOT learning something. All it does is decrease our signal-to-noise ratio, in which many of us will have to correct. The task of addressing the original question can be difficult enough. We don't need the added burden of correcting the offered answers as well.

Zz.

 

[trogan]

So which part of "mainstream QP" did you get this from?

Zz.

My "bible" is Quantum Reality by Nick Herbet. I have a number of other books that I use as reference mostly geared to non-physicists.

Also internet searches (lots), for example http://en.wikipedia.org/wiki/Quantum" . I can retrieve them from history if you want to know them but at least half I would say are authoritative.

Also PF itself of course although I have forgotten exactly which threads.

 

[trogan]

So which part of "mainstream QP" did you get this from?

If you want to learn something, ASK.
Zz.

Believe me I have been asking, pleading almost ! My original post was to ask for the definition of a quantum and also to verify a description of Planck's Constant that I had come across on the internet. NONE of my questions have been answered which really puzzles me. What then happens is that I do a bit more study and come up with an answer myself which I then post and ask is it correct.

 

[trogan]

All it does is decrease our signal-to-noise ratio, in which many of us will have to correct.
Zz.

Thanks for informing me of the difficulty of your task. I will be a lot more careful about my posts in future.

 

[ZapperZ]

My "bible" is Quantum Reality by Nick Herbet. I have a number of other books that I use as reference mostly geared to non-physicists.

Also internet searches (lots), for example http://en.wikipedia.org/wiki/Quantum" . I can retrieve them from history if you want to know them but at least half I would say are authoritative.

Also PF itself of course although I have forgotten exactly which threads.

Can you quote exactly where your "bible" actually claims that protons being the basis of matter? I mean, how in the world does one reconcile the existence of leptons? Besides, how would you know what you read in there is part of "mainstream physics"? After all, a pop-science book can easily be speculating something that isn't accepted yet (example: Brian Greene's "Elegant Universe").

You need to keep in mind that you might have a faulty understanding of what you read, or that you didn't get the complete picture. It is why you shouldn't be so quick at offering someone an answer.

Zz.

 

[trogan]

Can you quote exactly where your "bible" actually claims that protons being the basis of matter? I mean, how in the world does one reconcile the existence of leptons? Besides, how would you know what you read in there is part of "mainstream physics"? After all, a pop-science book can easily be speculating something that isn't accepted yet (example: Brian Greene's "Elegant Universe").

You need to keep in mind that you might have a faulty understanding of what you read, or that you didn't get the complete picture. It is why you shouldn't be so quick at offering someone an answer.

Zz.

Here is a review of my "bible" on Amazon ... from a physicist:

"This book is, without a doubt, one of the best nontechnical physics books I have read. As a kid in high school, this book was my first introduction to the mysterious world of quantum physics. I was amazed that, despite my technical illiteracy, Herbert gave me both insight into the inner mathematical workings of quantum mechanics, and into the deeply troubling conceptual problems that this radical theory forces upon us. Even today, as a graduate student in theoretical physics, I have a more profound appreciation for quantum mysteries than any of my classmates, simply because I read this book in high school. I would recommend this book for the layperson and the quantum field theorist alike!"

There is no mention in it of protons being the basis of matter. I have said that this is pure speculation on my part and I don't want an answer on it. Like most of my speculations it will most likely turn out to be just that ! I am sorry I raised it.

You need to keep in mind that you might have a faulty understanding of what you read, or that you didn't get the complete picture. It is why you shouldn't be so quick at offering someone an answer.

Zz.

With QP the chance of this happening is obviously extremely high. I do think long and hard about what I say and I try and couch my language in words like "seem" and "guess" to make sure that the reader is aware that I am not offering what I say as "gospel".

For example the full sentence of a statement you have criticised me for is:

"It is the very basis of Quantum Mechanics and I am guessing if you (like I used to) think of it as E/f then your understanding of Quantum Physics is not as deep as it could be (I am willing to be shot down in flames on this statement !).".

I do say twice in it that I am not sure of my facts.

 

[Physics Monkey]

Hi trogan,

I'll take a stab at some of your questions.

1. I am not aware of anybody that regulates or mandates usage of the word quantum.

2. When speaking to my colleagues about physics, I use quantum (or variants of it) as an adjective, noun, and verb (at least).

-- Examples of adjective usage: quantum physics (physics associated with the very small, etc, based on the ideas of Planck, Einstein, Bohr, Heisenberg, etc), quantum field theory (the combination of quantum physics and classical field theory), quantum information theory (the combination of quantum physics and classical information theory)

-- Examples of noun usage: quantum of energy (a unit of energy), quantum of light (a photon), flux quantum (a particular amount of magnetic flux relevant to the physics of superconductors)

-- Examples of verb usage: to quantize a theory (a process of taking a classical theory and producing a quantum version of it i.e. to quantize the electromagnetic field is to pass from classical electrodynamics to quantum electrodynamics)

3. Wave mechanics is not inconsistent with quantization of energy. Since you indicated a desire to avoid mathematics, I shall try to be heuristic. For a particle in a box, the quantization of energy comes from the requirement that the wavelength of the particle fit into the box. So assigning a particle wave like characteristics does not automatically imply that everything is "continuous". This is actually a result familiar from the classical theory of the electromagnetic field i.e. the discrete possibilities for electromagnetic waves in a cavity.

Hope this helps.

PS Please let me know if I've been too heuristic for you.

 

[Born2bwire]

See my first post.

My understanding is that it is the Unit of Action of a Quantum of Energy. Maybe it could be called "oomph" ! It is applicable not only to photons but to ANY particle containing energy (all of them ?). It stands by itself as a unit.

It is the very basis of Quantum Mechanics and I am guessing if you (like I used to) think of it as E/f then your understanding of Quantum Physics is not as deep as it could be (I am willing to be shot down in flames on this statement !).

The fact that you have no idea of what action is rather disturbing in its own right. If you want to know what the action is you need to learn Lagrangian physics and then path integral theory and how it relates to quantum mechanics and quantum field theory.

 

[Vanadium 50]

I am not exactly a novice. Well-informed amateur would be a better way of putting it... I do have as my bible a book "Quantum Reality" by Nick Stevens which gives an eye-opening explanation of the quantum.

It's Nick Herbert, and reading a popular book does not make someone well-informed on a topic. Certainly not well enough to tell experts they are wrong.

The fact that you have no idea of what action is rather disturbing in its own right.

Born2bwire is right - there is something in mechanics called action, but it is more precisely defined than "oomph". It is not an energy, and if you took a look at the units, you would see that it doesn't even have the units of energy.

 

[trogan]

The fact that you have no idea of what action is rather disturbing in its own right. If you want to know what the action is you need to learn Lagrangian physics and then path integral theory and how it relates to quantum mechanics and quantum field theory.

If I am disturbed by something or someone I take it as an opportunity to learn something about myself. Why am I disturbing you ?

I did specify a definition for action in my opening post as "Mathematicians define action as an object’s momentum multiplied by the distance it travels; or the object’s energy multiplied by the time it is traveling–the two are equivalent.". The definition then went on to elaborate on this. This was not my definition but one I picked up from the internet.

It seems to me this is quite adeqate for a basic understanding what a quantum of energy is all about.

It also seems to me that the techniques you talk about contribute to a deeper understanding of action, especially in QF theory, yet it does not appear to be a complicated entity.

 

[trogan]

Hi trogan,

3. Wave mechanics is not inconsistent with quantization of energy. Since you indicated a desire to avoid mathematics, I shall try to be heuristic. For a particle in a box, the quantization of energy comes from the requirement that the wavelength of the particle fit into the box. So assigning a particle wave like characteristics does not automatically imply that everything is "continuous". This is actually a result familiar from the classical theory of the electromagnetic field i.e. the discrete possibilities for electromagnetic waves in a cavity.


PS Please let me know if I've been too heuristic for you.

Thanks for your heuristically fine replies. I am not sure what you maen by wave length of a particle but don't want to pursue that now.

 

[trogan]

It's Nick Herbert, and reading a popular book does not make someone well-informed on a topic. Certainly not well enough to tell experts they are wrong.

Born2bwire is right - there is something in mechanics called action, but it is more precisely defined than "oomph". It is not an energy, and if you took a look at the units, you would see that it doesn't even have the units of energy.

Nick Herbet, of course. Thanks for the correction.

Oomph is pretty evocative though, don't you think . You are confusing me. I was under the very strong impression that the Quantum Unit of Action (or Planck's Constant) is 6.62606896(33)×10−34 J·s and Joules is a unit of energy. Is this not the case and if so what then do you mean ?

 

[Born2bwire]

If I am disturbed by something or someone I take it as an opportunity to learn something about myself. Why am I disturbing you ?

I did specify a definition for action in my opening post as "Mathematicians define action as an object’s momentum multiplied by the distance it travels; or the object’s energy multiplied by the time it is traveling–the two are equivalent.". The definition then went on to elaborate on this. This was not my definition but one I picked up from the internet.

It seems to me this is quite adeqate for a basic understanding what a quantum of energy is all about.

It also seems to me that the techniques you talk about contribute to a deeper understanding of action, especially in QF theory, yet it does not appear to be a complicated entity.

The problem is that when I asked you what the action was, you could not give it to me. You stated that the electron and photon have the same "action potential" yet you can not give me what that potential is when I asked. You need to start learning more about these things before you start basing conclusions upon them.

More importantly, how would having the same action dictate that two situations are the same? Going from the definition you reference, energy times time, I could give you the "action" in this sense of a 1 ton car that travels 1 second at 100 km/hr and say that it is the same as the action of a mole of C_60 buckyball traveling at 54 ft/s for 1 hour. What is of interest is how the action relates to physics in general, through its use in Lagrangian physics. If you learned about Lagrangian mechanics then you would easily see the answer to your question.

As for Planck's constant, to me, it really doesn't mean anything of much consequence. It's just a constant, we can always set it to any arbitrary non-zero number depending on our desired system of units. For example, if we were to use natrural units, then c=\hbar=1. The ubiquitious nature of \hbar popping up everywhere makes it rather difficult to describe what it is since it is present in the basic principles of quantum mechanics, like Schroedinger's equation or Feynman's path integral formulation. However, it is of interest that classical mechanics can be recovered by taking the limit of \hbar to zero with the path integral formulation.

 

[trogan]

The problem is that when I asked you what the action was, you could not give it to me. You stated that the electron and photon have the same "action potential" yet you can not give me what that potential is when I asked. You need to start learning more about these things before you start basing conclusions upon them.

More importantly, how would having the same action dictate that two situations are the same? Going from the definition you reference, energy times time, I could give you the "action" in this sense of a 1 ton car that travels 1 second at 100 km/hr and say that it is the same as the action of a mole of C_60 buckyball traveling at 54 ft/s for 1 hour. What is of interest is how the action relates to physics in general, through its use in Lagrangian physics. If you learned about Lagrangian mechanics then you would easily see the answer to your question.

As for Planck's constant, to me, it really doesn't mean anything of much consequence. It's just a constant, we can always set it to any arbitrary non-zero number depending on our desired system of units. For example, if we were to use natrural units, then c=\hbar=1. The ubiquitious nature of \hbar popping up everywhere makes it rather difficult to describe what it is since it is present in the basic principles of quantum mechanics, like Schroedinger's equation or Feynman's path integral formulation. However, it is of interest that classical mechanics can be recovered by taking the limit of \hbar to zero with the path integral formulation.

Okay, thanks a lot for that. I see where you are coming from. Action Potential was, like oomph, just something I dreamed up but it seemed very evocative and a hell of a lot easier to talk about than Unit of Action of a Quantum of Energy. Plus it had a rest mass connotation as in Potential Energy.

 

[Vanadium 50]

the Quantum Unit of Action (or Planck's Constant) is 6.62606896(33)×10−34 J·s and Joules is a unit of energy.

Joules are a unit of energy. Joules times seconds are not a unit of energy.

Action Potential was, like oomph, just something I dreamed up but it seemed very evocative and a hell of a lot easier to talk about than Unit of Action of a Quantum of Energy. Plus it had a rest mass connotation as in Potential Energy.

And what we are trying to tell you - and it's evidently not sinking in - is that you don't get to "dream up" stuff until you've learned something first.

 

[trogan]

Joules are a unit of energy. Joules times seconds are not a unit of energy..

Fair enough. Do you mean Joules times second (i.e. 1 second) ?

And what we are trying to tell you - and it's evidently not sinking in - is that you don't get to "dream up" stuff until you've learned something first.

I have mea culpa'ed on this in a previous post.

 

[trogan]

Fair enough. Do you mean Joules times second (i.e. 1 second) ?

So, this seems to be saying that the quantum in QP is a quantum of action, not energy. And it therefore seems to me that time always needs to be involved if energy is to be manifested (maybe a better way of putting it is "if energy is to be involved in an interaction"). Where does that leave E=mc2 ? Can anone enlighten me on the flaws in my logic ?

 

[Vanadium 50]

The "flaw in your logic" is that you continue to try and hypothesize first and learn second.

You will make more progress by trying to learn what QM actually says than by posting your own hypotheses and asking us to show you the mistake. (It also is disrespectful of others' time - it says "I am not willing to put the effort into get this right, but want you to put in the effort to find where it's wrong.")

 

[trogan]

The "flaw in your logic" is that you continue to try and hypothesize first and learn second.

You will make more progress by trying to learn what QM actually says than by posting your own hypotheses and asking us to show you the mistake. (It also is disrespectful of others' time - it says "I am not willing to put the effort into get this right, but want you to put in the effort to find where it's wrong.")

I am trying to build up a picture of QP at its most basic. I am having great difficulty (to say the least). As I am pretty intellegent I would guess others are in a similar boat. And it seems obvious that if people don't get the basics right then QP will be difficult for them all the way through.

I never ask a question unless I am completely stumped, as in this case. I always seek to use whatever means I have available to gain understanding before I ask a question. It is not only more satisfying that way, it makes the knowledge gained deeper and more lasting than would otherwise be the case.

I have more questions that I am stumped on:

1. Can anyone tell me what energy times second actually means ? As it is the very basis for QP I would expect that it would be clearly explained in textbooks and elsewhere. I have not found this to be the case.

2. Also, what is frequency in the equation E=hf as it relates to a photon ? I have been told that it is frequency of a photon but this makes no sense at all. Does a photon vibrate (I presume this means move up and down or side to side) ? How can a photon's energy vary if it always travels at the speed of light ? I have seen E=hf as relating to the wave function (i.e. f is the frequency of a wave in a particle's wave function that relates to the energy attribute of the particle) but few explanations I have met seem to take this viewpoint.

 

[Born2bwire]

So, this seems to be saying that the quantum in QP is a quantum of action, not energy. And it therefore seems to me that time always needs to be involved if energy is to be manifested (maybe a better way of putting it is "if energy is to be involved in an interaction"). Where does that leave E=mc2 ? Can anone enlighten me on the flaws in my logic ?

Once again, you need to look up and learn what Lagrangian mechanics, path integral, and the action are if you are going to start asking questions based on assumptions of their character.

 

[trogan]

Once again, you need to look up and learn what Lagrangian mechanics, path integral, and the action are if you are going to start asking questions based on assumptions of their character.

Thanks for your reply. So are saying that I cannot understand the basics of QP without advanced expertise in the areas you mention ?

 

[DaveC426913]

So are saying that I cannot understand the basics of QP without advanced expertise in the areas you mention ?

No, I think what everyone is saying is you cannot draw your own conclusions without advanced expertise in the areas they mention.

 

[trogan]

No, I think what everyone is saying is you cannot draw your own conclusions without advanced expertise in the areas they mention.

My conclusions are definitely not conclusions. They are all questions. I don't have the answers, believe me. It seems to me that I am just stating the obvious but with a twist that is missing from normal explanations of QP.

I am just interested in the basics of QP. As I have received almost zilch in the way of answers to a myriad of questions, I am starting to surmise that even questions on the basics are not answerable. This is a thread where I sarted with what I thought would be a simple question on the standard definition of a Quantum. And it has now run to 4 pages with almost no answers being provided. Something mighty strange is going on although I concede it is not beyond the realms of possibility that people find me objectionable and are not willing to help ! Hopefully not.

 

[trogan]

Once again, you need to look up and learn what Lagrangian mechanics, path integral, and the action are if you are going to start asking questions based on assumptions of their character.

Can you please tell me whether my definition of action in post #1 is correct or not.