Ask any question you want about Physics

a reply to: ImaFungi
If you ask about a group of electrons emitting numerous photons, classical electromagnetism in say a dipole antenna can result in EM radiation in a "donut" or torus shape as you suggested a photon would have.

You can apply maxwell's equations to these problems and get good approximations.

The problem as you state it with a single electron, and potentially one or a small number of photons emitted from that electron, is that quantum effects become significant on that scale and in that case QED, the more accurate model, is needed for more accurate predictions. Dragonridr started to explain some QED concepts to you and you just said "False" without elaborating. I'd say the ball is in your court to explain why you said "false". It seems like you're rejecting something you don't even understand.

So you have a couple of options:

-Most real world phenomena don't involve a single electron, so you can just stick with those and use classical approximations like Maxwell's equations. In that case the EM field radiates in all directions from say a dipole antenna in the shape of a torus.
-The other option if you insist on talking about single electrons emitting single photons, is to learn QED if you want to understand the quantum model which is more accurate on a quantum scale than Maxwell's equations. A single photon does not expand in all directions, though it can have a probability of going in many different directions, depending on how you are accelerating it.

a reply to: Arbitrageur

Starting my conversation with you on this topic, I was only ever talking about ONE electron, being accelerated ONCE. You failing to read the words I wrote and understand them, is not my failure.

I began the conversation on this topic because I felt and observed that people like yourself believe or believed that one electron emits one photon, one photon being a particle or wave packet or wave of omni directional 'energy'. Because I felt and observed this belief of yours and others, I began this conversation, to attempt to extinguish your ignorance on that topic, and hopefully now you know that that view is incorrect. There is no need to backtrack and attempt to smudge your errors and attempt to smudge my perfection to make it appear as if I erred, we are all trying to embody truth around here, and that takes nothing more than honesty, in the truest sense.

a reply to: Arbitrageur

Are you a Professional physicist?

a reply to: ImaFungi
Yes you brought up one electron. I did understand this.

Your analysis of what happened with that one electron and the photon you talked about then falls under the domain of quantum mechanics, but your analysis wasn't based in quantum mechanics. The reason I brought up multiple electrons was to show you a case where your classical description would apply. If you insist on one electron and you talk about individual photons as you did, then you need to apply quantum mechanics in that case, which you didn't do that I could see.

Whether the electron emits one or more than one photon depends on how much you excite it:

Device emits single photon

One single photon. One solitary quantum pulse of electromagnetic radiation, no more, no less, produced by one single electron, will be the product of a new device under construction by nanotechnologists at the USC Viterbi School of Engineering.

That one photon comes from that one electron because that's what they want their experiment to do. If they wanted more than one photon from that one electron they could surely set up a different experiment to do that.
I'm not sure what I ever said that led you to think I thought the electron was limited to emitting only one photon, but it can be so limited if desired as that link explains.

a reply to: spy66
My background is similar to Bedlam straddling both physics and engineering. If you keep getting promoted, you end up with so many managers working for you that leading and directing their efforts and that of their staffs takes so much of your time that you don't get to spend as much time on physics or engineering as you might like.

Lol maybe a professional webbot.
a reply to: spy66

a reply to: Arbitrageur

I am talking about theory. I am talking about thinking about truth. I can KNOW something you say is false, by using inference and deducing, from the totality of all my knowledge. The funny thing is, the quantum mechanical interpretation infers and deduces the illogical and irrational view.

So I am speaking about ONE electron, being accelerated (it doesnt matter once or many times...I use once to be as simple and fundamental as possible... the only reason I am bringing up this topic, is to get to the most basic fundamental comprehension of general aspects of some the most fundamental aspects of reality; the electron and EM radiation). This has not been able to be done in experiment yet, maybe it has, and I posit even if it has, there will be aspects about it, that will not on their own yield knowledge.

Do you know how the electron is coupled to the EM field? Do you understand, do you know, do you see, do you think about, how the electron is coupled to the EM field?

Do you know, do you understand, do you see, do you think about, what occurs, planck time and planck space by planck time and planck space, what occurs, as a charged particle/em radiation approaches an electron (for we want to accelerate an electron, to determine how radiation propagates away from it, we must use at least a charged particle, which uses at leas EM radiation in some capacity)?

Do you know, do you understand, do you see, do you think about, what occurs, at the point of initial acceleration, on through to the new electron trajectory, and how the local EM field of the electron, changes in relation to the time and space topography from the point of initial acceleration on through to the new electron trajectory?

Any intelligent being that reads the last few pages will see me focused on the same simple thing, simple in the fact I am only focused on the electron and the EM field. Any intelligent being that reads the last few pages, will read my questions, which are pretty much the same ones over and over again, in different and new uber thorough ways, and each time, you respond by running in utter fear from the implications of you actually reading what I wrote, understanding what I mean, understanding that you do not know or comprehend how to answer my perfect questions, and perfect scientific inquiry, and so you respond by doing anything but facing the truth. The truth being, I asked a poignant question on a poignant topic, and you or maybe no human ever alive has known the answer to, and so instead of trying to think about it, instead of trying to argue my deductions and inferences as they are, you falsely believe that the most appropriate deduction and inference is that believing probability tools to organize massive amounts of experimental data, is reality itself. It is the safe option, if I had no integrity, did not care about truth, was a scared child, I would do whatever feels most comfortable, I wouldnt want to be bothered by scary thoughts, or that daddy scientists couldnt be severely inspired intelligences, I wouldnt want to think hard about a subject, I would want to believe that the crude map was reality, and not think about reality, its so much easier, its so cozy, you really dont have to think yourself, you can just read, and then know truth, no thinking, its so nice and comfy, that is obviously the smartest thing to do, be easy and comfy.

I have a question for you:

Can we support using lighter than air gas filled wind modules that when connected form an evacuated tube strong enough to propel space ships into orbit and long enough to keep the acceleration forces to comfortable levels ?

Search for Open Source Space Elevator on YouTube or Google to get a better picture of what I mean.

originally posted by: EMSpaceLift
I have a question for you:

Can we support using lighter than air gas filled wind modules that when connected form an evacuated tube strong enough to propel space ships into orbit and long enough to keep the acceleration forces to comfortable levels ?

Search for Open Source Space Elevator on YouTube or Google to get a better picture of what I mean.

No first anything modular would be torn apart by the stress just supporting its own weight. Not to mention the people dont realize the middle has to be significantly stronger and thus thicker. making the weight to much. Even experiments with carbon nano tubes is uncertain you have to make a vehicle that can claim a rope of varying thickness. And well the counter weight would have to be pretty dam heavy so shoving a space station at the top wouldnt be enough. Guess you could extend the cable further out but than we also increase the stress on it. with todays technology id have to say impossible.100 years from now who knows we might find a way to alleviate the stresses.got to admit it be cool though !

a reply to: ImaFungi

The totality of your knowledge wow thats funny. See if you dont bother to study about and learn about what we do know you end up denying reality. People thought the wright brothers were nuts the totality of there knowledge told them people cant fly. Now as far as your question yes i can tell you how they interact theirs the basic way and well the complicated one. Basic ius the electron wiggles creating a wave we see as em radiation or a photon if you will. In quantum mechanics its an electron-proton system interacting with the quantized electromagnetic field which leads to the emission of a photon. dont know why i bother ???

a reply to: dragonridr

When one electron is accelerated the minimum amount to be considered acceleration; How does the EM field surrounding and coupled to, the accelerated electron, react?

originally posted by: ImaFungi
a reply to: dragonridr

When one electron is accelerated the minimum amount to be considered acceleration; How does the EM field surrounding and coupled to, the accelerated electron, react?

Have you bothered to look at any of the videos and textbooks I posted? They show what you want to know. You ask the question---time to look at the answers, and start using google.

If you want to know how to compute the fields exactly, the Lienard-Wiechert potential will do it.

en.wikipedia.org...

originally posted by: ImaFungi
a reply to: dragonridr

To be thorough, I will start most simply.

" Imagine an electron which is not moving and stationary. According to Coulomb's law, a field is produced by this electron."

What are the words/terms you wish to use to express to me what this field is made of, and in what physical manner the stationary electrons stationary field exists?

After you answer that, I will ask if your description of how that physical field exists, 'physically stops existing' at some point, at a distance away from the stationary electron.

It doesn't ever physically stop existing. It always was since Big Bang.

To clarify by my use of the term physical and/or exist, what I mean is that, for example, when you say 'a field is produced', I would say, if the field that is produced is anything except for absolute pure nothing, than I would say that field exists, and is physical. If you dont like my use of the term physical to denote 'that which in some way exists', than I will use the term exists, or non nothing.

In the field theory in Standard Model there are fields which exist everywhere in all of space in the Universe. Their values and wavefunctions and motion thereof describes all the motion of all stuff in the Universe. Every photon which ever existed and will is an excitation of the EM field. Every electron is an excitation of the electron field.

a reply to: ImaFungi

you are being long-winded. The classical theory of fields produced by stationary, moving and accelerated charges is complete, quantitative and comprehensive. This is what people learn when they study physics, which you have yet to do. Start doing so.

a reply to: mbkennel

Why would I want to learn how to compute a field when you dont even know what a field is?

Just give me a hint, is the field effected only in one infinitesimal direction away from the electron? Or at least more than one?

a reply to: Arbitrageur

What is "outside" of the universe?

If the universe is expanding as a result of the big bang, that must mean that there is something for it to expand into. What is that, and how is it quantifiable?

originally posted by: mbkennel
Every photon which ever existed and will is an excitation of the EM field.

What is the EM field where there are no excitations/photons?

a reply to: mbkennel

I am just trying to prove Arbs belief wrong.

He believes when a single electron is accelerated, EM radiation is only propagated in one infinitesimal direction. I intuitively suggested that that does not seem plausible, and asked him to support his claims with additional statements. I suggested when a single electron is accelerated, it seems as if EM radiation would propagate away from the electron in multiple directions, potentially even 'connected' in some way, like a ring/circle, which expands its area in relation to the point the electron was at in space, when it was accelerated (electron being the common central point of this circle).

We have really drifted by now, as I remember maybe 20 pages ago when I brought this simple concept up, I had other ideas I thought would tie to it, with whatever we were arguing about then. I think it might have been related to my thought that if that is the case, then would there be a difference between detecting two areas of this ring at x distance away from point of electron acceleration, and detecting two areas of this ring at y distance. Thinking, would there be more available 'points for detection' over time, as the ring expands, as there are more points of detection over time, to a circle of water ripple after a stone dropped in the water, the more the circle expands, and how this relates to the energy therein.

originally posted by: ImaFungi
a reply to: mbkennel

Why would I want to learn how to compute a field when you dont even know what a field is?

To learn physics.

Just give me a hint, is the field effected only in one infinitesimal direction away from the electron? Or at least more than one?

Every direction.

You're probably confused with quantum mechanics where the EM field is connected to probabilities of observing photons--the latter may be compact (like gamma-rays in a photo detector) and isolated but the EM field spreads out.

originally posted by: ImaFungi

originally posted by: mbkennel
Every photon which ever existed and will is an excitation of the EM field.

What is the EM field where there are no excitations/photons?

It has value zero, classically, yielding a 3-d vector at the origin for electric and magnetic fields: E(x,y,z,t) = (0,0,0) = B(x,y,z,t).

In quantum field theory the wavefunction of the EM field (note, a different object than the Maxwell field) is in the vacuum state, and this is not mathematically zero, although it is what is meant by empty space.

Note when people say a photon is an excitation of the EM field, it really means it's an excitation of the wavefunction of the EM field which is the fundamental quantity in QFT.

In classical physics (Maxwell) there is no minimum energy or size, i.e. the value of E & B can be as small as you like. In quantum physics (QED), this is not true for any finite frequency/wavelength.

originally posted by: ImaFungi
a reply to: mbkennel

I am just trying to prove Arbs belief wrong.

He believes when a single electron is accelerated, EM radiation is only propagated in one infinitesimal direction. I intuitively suggested that that does not seem plausible, and asked him to support his claims with additional statements. I suggested when a single electron is accelerated, it seems as if EM radiation would propagate away from the electron in multiple directions, potentially even 'connected' in some way, like a ring/circle, which expands its area in relation to the point the electron was at in space, when it was accelerated (electron being the common central point of this circle).

We have really drifted by now, as I remember maybe 20 pages ago when I brought this simple concept up, I had other ideas I thought would tie to it, with whatever we were arguing about then. I think it might have been related to my thought that if that is the case, then would there be a difference between detecting two areas of this ring at x distance away from point of electron acceleration, and detecting two areas of this ring at y distance.

Classically yes, unless you have a plane wave, the intensity will be lower the further away you are. This is physically obvious because of conservation of energy.

In quantum mechanics this means that the *rate* of detecting photons per unit time through a certain area will be lower the further away you are. Roughly, the rate of detecting photons will be proportional to the energy flux computed classically which is the Poynting vector integrated over a surface.

The image sensors on common digital cameras are sensitive and with the electronics, can count individual photons. This is why physically larger sensors give better pictures with less 'grain': they are averaging a larger number of photons and the effect of the random QM fluctuations is diminished.

Thinking, would there be more available 'points for detection' over time, as the ring expands, as there are more points of detection over time, to a circle of water ripple after a stone dropped in the water, the more the circle expands, and how this relates to the energy therein.

Yes that's correct for acceleration of a point charge. I think you were misunderstanding Arb and the difference between the classical field and quantum mechanics involving that field, how you can have a spreading and continuous field in many directions, and simultaneously observe compact photons pointing in one particular direction (when observed) related to that field (which is spreading). This is not intuitive in the slightest and can't be truly understood without knowing the mathematical description of those words.

To take something morbid in the news, pretend that the "area of spread of Ebola virus cloud on a map" is like the field, and each occurrence of an individual person getting sick in a particular location like the observation of a photon.
(QFT is more complicated still but this serves as a start).