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There are various types of of charges 1/3,2/3 etc What do you mean by fundamental?

In introducing one of the fundamental properties of matter, it is perhaps appropriate to point out that we use simplified sketches and constructs to introduce concepts, and there is inevitably much more to the story.

Could someone explain to me the concept of electric charge? Why is it considered a fundamental property?

I assume you couldn't be satisfied saying simply "charge is that property of bodies that make them attract or repel by Coulomb interaction".

the subject of physics today resembles a cracked and broken path, like crazy paving rather than a smooth whole

Shouldn't therefore our concept of charge be based on the ability of a particle (such as an electron or a proton etc., ) to absorb and emit photons?

how can the concept of charge be considered as a separate issue in which photons play no part at all.

Physics is really just a system of models which help to predict what will happen under certain circumstances. Those models work remarkably well - to such an extent that human technology uses it all the time very successfully.

This anomalousness in our thinking is one of the central reasons that the subject of physics today resembles a cracked and broken path, like crazy paving rather than a smooth whole.

However, in 1919, soon after General Relativity itself was published in 1915, Theodor Kaluza and Oskar Klein noticed that adding an extra dimension to Einstein's equations effectively incorporated Maxwell's equations into them. Thus 4-D spacetime would not be curved by electromagnetic forces -- there is now just an additional dimension of spacetime, five in all, and only electrical charge and magnetic polarity "see" curvature in the fifth.

Walk into a totally dark room ! Switch on a light, what do you see? The radiation (photons) from the light bulb is absorbed by electrons in the atoms of the objects in the room and then re-emitted at certain frequencies enabling us to see colours, shapes etc., What am I trying to say ? We know that electrons (all electrons) interact with the environment through the emission and absorption of photons. This being so how can you then turn around and say that the electron has a charge? It doesn’t make sense and it means that rather than rely on observable evidence such as the emission and absorption of photons by electrons, and the subsequent gain or loss in energy, we are bringing in an unfounded deduction that the electron has charge.

The statement, when looked at in a logical manner, makes absolutely no sense. Charge is defined as a fundamental property of certain elementary particles of matter. There are two types of charges – positive and negative, like charges attract each other and unlike charges attract. But is this really true. What is a negative charge and what is a positive charge. Isn’t it well established that a negative ion is an atom that has lost an electron, while a positive ion is an atom one that has gained an electron ?

But what lies behind this process , an electron in an atom absorbs a photon gains enough energy and leaves the atom altogether leaving behind a negative ion or an atom that has emitted a photon might gain an electron and thus become a positive ion.

Shouldn’t therefore our concept of charge be based on the ability of a particle (such as an electron or a proton etc., ) to absorb and emit photons? Take the case of a proton, it doesn’t emit or absorb positrons, it absorbs and emits photons, in order to gain or lose energy.This is one of the reasons that atoms can exist, the constant absorption and emission of photons by the electrons in the atom. The most frequently used argument is that the photon is a neutral particle (i.e., it is not affected by magnetic fields) but if that is so how is the fact that an electron that absorbs a photon experiences a gain in energy (i.e., is positive ) while an electron that emits a photon experiences a loss in energy (i.e., is negative.) explained?

Is the most widely accepted view that a positive electric charge is gained by an object when it loses electrons and a negative charge acquired when it gains extra electrons fundamentally wrong? My point is if you are going to state (as quantum mechanics ) does that electrons interact with their environment by the absorption and emission of photons, how can the concept of charge be considered as a separate issue in which photons play no part at all. Attraction and repulsion is explained in quantum mechanics in terms of the exchange of photons

QuotePhysics is really just a system of models which help to predict what will happen under certain circumstances. Those models work remarkably well - to such an extent that human technology uses it all the time very successfully.As far as that goes, I am perfectly in agreement with you, it does work. But that doesn't mean it is right. Take for instance the flow of a current in an electrical conductor. Now as has long been established photons have been discounted as energy carriers... Why? The distance between free electrons in a metal conductor would be approx equal to billiard balls spread sevaral kilometres apart, (more than 10 ^^5 their diameter) so the chances of them hitting into each other and thus propagating a current is ridiclous.

The only way in which these electrons could possibly communicate over such distances is through the emission and absorption of photons. It is not a question of pushing table tennis balls in at one end of the conductor and seeing them come out the other end, there are vast interstitial distances involved. Secondly the drift velocity of electrons in a conductor carrying a current is very very slow, even by normal standards it is about 10 ^^ -3 cms/second. While light and electric current both travel at approx: 300,000,000 m/sec. Quite a difference don't you think. Photons are the only thing that we know of that travel at this speed. Is this just a conicidence or does it mean something?

My point is that by pushing photons completely out of the picture in the carrying of energy, such as a current, we are doing ourselves a disservice. Because as we very well know photons do carry energy. And in the same vein would exploration of such a possibility ( which hasn't yet been done) improve upon our present model?

My point is that by pushing photons completely out of the picture in the carrying of energy, such as a current,

Now as has long been established photons have been discounted as energy carriers... Why?

Substitute the word "photons" with the word "electric field".

I, personally, try for the classical approach first, and then launch into the hard stuff.

The propagation of current doesn't need electrons hitting into each other, on the contrary, they don't have to hit into each-other at all! It's the propagation of electric field that acts on all the electrons.

Mr Maxwell connects the concept of charge, current and electromagnetic waves very well and certainly doesn't push photons out of any picture. They are brought very much into the picture. His three equations tie in with quantum theory ok and relate all of that together quite reasonably.

Where have you seen this? Alternating current on a wire can be viewed ENTIRELY as an em wave (i.e. photons). The way a radio antenna operates can be explained completely in terms of guided waves.DC flowing in a wire involves photons of (near) zero energy - which involves a (near) infinite number of them. Where's the problem?

It isn't. It's when charges change their relative spacial arrangement that a photon with appropriate energy is involved. The energy of a photon which is associated with 'no change' is zero - that is fair enough.

So when you have a radiating force

And why do you keep referring to electrons as emitting or absorbing a photon? It is the system, containing the electron, that does the radiating.

But what if there was a way around this that HUP (Heisenberg Uncertainty Principle) itself supports?

This really does seem to be the heart of the problem! According to the PEP(Pauli Exclusion Principle) free electrons cannot emit or absorb photons, under any circumstansces.

Could you help me with why the PEP forbids a free electron from getting energy? Surely an isolated fermion can do what it likes? It's only in bound states that the PEP comes into significance. And what is Mr Heisenberg's part in this, at the moment? Are we measuring anything?

Btw, McQueen, I looked at your website and was surprised to find no maths amongst all your assertions. Do you have references to more detailed information about your ideas? They would need quite a bit of supporting theory to justify some of them if they are to be taken seriously.

Sorry but this is meaningless, said in this way. A "free" body of any kind is free because no forces, no potentials, no fields act on it, so there isn't any light that it could absorb or not.

It's true, on the other hand, that such an electron cannot absorb totally a photon, because in that process 4-momentum wouldn't be conserved (said in another way: momentum and energy wouldn't be conserved at the same time).

And why would you say the Maxwells' equations are not recognised by quantum theory? It is not surprising that equations developed long before QM, need some help but they represent the limit as microscopic tends to the macroscopic. I was not aware that they are actually wrong. If you were an actual quantum physicist you might be able to put me right, perhaps?

This post I would like to focus on the article that was posted by lightarrow about GR and charge. I myself have come to a similar conclusion after hearing GR described in my high school chem class, though I did not realize, as I do now, that it is the temporal dimension that bends and not the spatial ones.

This train of thought leads to two questions in my mind: is time simply a measure of the properties of matter which enable interactions (i.e.- mass and charge)?

and then, to describe any object or particle, all that would be needed would be two quantities, one a measure of spatial dimensions and one a measure of temporal dimensions (rather, dimensions of interaction, due to the ambiguity of the definition of time)? Is it possible to have a function Γ = O + D such that O is a function purely concerned with spatial variabls and D a function solely dealing with variables of interaction?

Although this concept is WAY beyond my mathematical ability to develop, is it at least plausible? What about the HUP and the uncertainty that would have to be inherent in O? Wait, and if D is the 'temporal' function, shouldn't there be some uncertainty in it too?....crash and burn! [:-'(]

I find this whole debate pointless. I do not argue about things I don't understand completely because they end up turning into someone who does understand them angrily and repeatedly shutting me down.

The question is: What is an electric charge? It can be described in terms of it's properties. For example, as the smallest unit of force that can be obtained by the interaction between two such charges, but that's not very satisfying, but neither is describing it as a cloud of certain photons.Lest you think I'm about to tell you what it is, however, I don't know either, but let me perhaps provide some food for thought. There is a wonderful theorem by W.V.D. Hodge that says on a closed manifold, and here I begin to speak loosely, a differential form can be expressed as the sum of the curl of a form or one lower dimension, the gradient of one higher dimension, and one of the same dimension whose gradient and curl are both zero. In even looser words, this means everything can be expressed as either a rotation or source, that is, as either a squirt or an eddy.In a Minkowski space there are six kinds of eddy with one associated with each plane. Three such planes have both coordinates whose square is positive, and three have coordinates with one dimension whose square is negative. Let us associate the first three of these with the magnetic field and the others with the electric. Charge is then the fourth component of the vector core of the electric field and the field is itself the eddy associated with the charge.Does this tell you what elecrtomagnetic field or the electric charge is? I don't think so, but perhaps it's food for thought. Incidentally. thank you McQueen for a delightful question.

lightarrow, I thought that the article you posted provided a fairly convincing argument for the statement that it is time that bends and not space. Of course by time bending I mean in relation to space (thus the concept of spacetime), not by itself. Time alone is time but considered as part of spacetime it is bent relative to space. That is at least what I got from the article (before it became unscientific).

What is Noether's theorem?

Isn't density a dimension, and surface area and all of those sort of things? A dimension in the sense that they describe a property of an object? That being true, I think it is a very logical deduction that charge and mass should be dimensions of an object. The only difference bewteen surface area and charge or mass is that surface area doesn't produce an acceleration while charge and mass do. Therefore, on the subatomic scale, shouldn't an object be merely a wave which has dimensions q and m (and one for the strong and maybe weak force too)? Come to think of it, I have never heard of a subatomic particle being described by size, only mass and charge (and spin, color, etc...). Macro objects (atomic nuclei and up for this case) are given a size by the distances their constituent particles are held apart then. Is space unaltered then by mass/charge/etc... and it is merely the time component of spacetime which changes (this having a component dimension for each interaction property of matter)? Does this make sense?

I guess it is a little weird, but let me give it a try. In two-space (a plane) there are only two types of field that are solutions of the laplaces equation. One is circles around a point, the other is radii emitted from a point.The same is true in the four-space of relativity. Maxwell's equations say the electromagnetic field is the eddy part. What I'm trying to say is charge is the core of the eddy for the electric field, that is the eye of the hurricane.

One of the most interesting and useful matematical theorems applied to physics. Everything starts from a function called "lagrangian" L which is T - V, T = kinetic energy and V = potential energy. The theorem put in relation physics symmetries with conserved quantities, starting from the lagrangian L. Examples:The physical system (its lagrangian) is invariant under space translations --> momentum is conserved.The physical system is invariant under space rotations --> angular momentum is conserved.The physical system is invariant under time translations --> energy is conserved.

Quote One of the most interesting and useful matematical theorems applied to physics. Everything starts from a function called "lagrangian" L which is T - V, T = kinetic energy and V = potential energy. The theorem put in relation physics symmetries with conserved quantities, starting from the lagrangian L. Examples:The physical system (its lagrangian) is invariant under space translations --> momentum is conserved.The physical system is invariant under space rotations --> angular momentum is conserved.The physical system is invariant under time translations --> energy is conserved.I am the last person to say that mathematics is not beautiful, but that does not make it any different from an abstract piece of art. Look at this site on ‘renormalisation’ not by one author but by many authors, ...sorry, you cannot view external links. To see them, please REGISTER or LOGIN and the funny thing is that they all say the same thing, namely that QM came up with infinities that were rationalized (read normalized) by replacing those infinities with finite values taken from actual observation . (Read: these beautiful mathematical concepts were framed around what was being observed and did not lead to them ….. by any means) Does this make sense, if it does, you are way ahead of me. N.B: It is important to note that all these people also think that ‘renormalisation’ (i.e., rationalizing a 10^^12 discrepancy) actually works. So there you have it , who is right in all this?

I haven't read those site, but, concerning renormalization, of which I know only very little, some physicists would agree with you that it's a nonsense. If you asked me, I would say that not even photons (as moving particles) exists, so you are talking to someone who believes in very solid-real things in physics, and that sometimes people don't understand exactly where physics ends and mathematics begins.

lightarrow, in regards to the paragraph on density and dimensions and what not, I was only trying to prove that charge is a dimension of matter like mass and so it's effects should be considered similarly (such as in the bending of spactime). The article you had posted early in the thread discussed the Kaluza-Klien modification to GR in which charge interacted with a fifth dimension and only other charged particles felt the effects of the bending of this dimension. This seems all too logical but it has not become a major component of relativity theory...why is that? It seems so very obvious (and I would toy with the idea quantitatively if only I had the mathematical background).

What if charge interacted with this fifth dimension of spacetime in the same manner as mass interacts with the first four dimensions? Many of the predictions of GR could be made for charges instead of masses. Light would bend in an electric field...etc. Like I said, I don't have enough math to play around with this, someday though....