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Author Topic: Do force-carrying particles exist?  (Read 12702 times)

Offline thebrain13

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Do force-carrying particles exist?
« Reply #25 on: 02/05/2011 07:47:41 »
gosh, reading stuff from 2007 is crazy, this was my least favorite thread ever. I think this is an example of me very thoroughly misrepresenting what I was trying to say.

I was questioning why do we believe that the forces have to travel in particles at all? What decisive proof exists that particles don't react with each other directly and smoothly over a distance? And that the "force carrying particles" are just misnamed pieces of mass.

The photoelectric effect isn't a good example because all it does is show that photons need specific amounts of energy to dislodge an electron. That fact doesn't really have anything to do with whether or not the photon is the carrier of electric and magnetic force.
« Last Edit: 02/05/2011 07:56:36 by thebrain13 »
 

Offline MikeS

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Do force-carrying particles exist?
« Reply #26 on: 02/05/2011 15:24:11 »
From your original post.
what evidence shows that a photon has any connection with electromagnetism

Brain you are talking rubbish.  go away and read some basic textbooks.

The simple explanation is you get one hydrogen atom in a slightly excited state one of its electrons changes its orbit, loses some electromagnetic energy and emits a photon and nothing else.  That is precisely how photons mediate the electromagnetic force ie every change of electromagnertic energy in every particle in a material invoves the emission and absorbtion of photons.



That seems to be the simplest and most straightforward answer to me.

Here is another that says the same thing even simpler:-

The frequency of light emitted by an electron is the same as the orbital frequency of that electron.

The photon and electron are the most basic 'particles' and the above shows their intimate equivalence
 

Offline MikeS

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Do force-carrying particles exist?
« Reply #27 on: 03/05/2011 12:06:05 »
And here's another completly but very obvious answer to the question:-

From your original post.
what evidence shows that a photon has any connection with electromagnetism

Your looking at it right now.   ;D
 

Offline ZedZzizz

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Re: Do force-carrying particles exist?
« Reply #28 on: 17/10/2012 01:36:38 »
Hi all,

Sorry for bumping a very old topic, but I am doing some personal research in this specific area and wanted to ask something specifically related to photons and EM force. are involved. What I don't understand is this thought experiment:

Initial assumption:
Virtual photons are the carriers for EM force even in static situations.

Initial setup:
Two oppositely charged parallel metallic plates are set up like a simple capacitor, inside the plates are an uniform static electric field, fringe fields are ignored.

Based on the force carrier model, virtual photons are responsible for this uniform electric field. A plate of non-conductive, non-polar material should be capable of blocking any photons (except for high energy ones?).

In this case, the force carriers would be unable to reach their destination and there would be no electric field.

But in reality the electric field passes straight through the non-conductive plate.

Where have I gone wrong?

Cheers Zed.
 

Offline yor_on

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Re: Do force-carrying particles exist?
« Reply #29 on: 17/10/2012 06:20:32 »
Think i got stuck on that one too some while ago? At least a similar one using two 'horse shoes'. And I found a answer to it but I'll have to look it up. And no Brain, your questions wasn't stupid, even then :) It's all about getting to see how people think, and using a forum like this for it helps a lot.
=

A nice question might be.. If photon's only push, how can a electro magnetic field attract? .. And I'm paraphrasing yours there Brain :)
« Last Edit: 17/10/2012 06:35:04 by yor_on »
 

Offline yor_on

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Re: Do force-carrying particles exist?
« Reply #30 on: 17/10/2012 08:56:37 »
 

Offline evan_au

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Re: Do force-carrying particles exist?
« Reply #31 on: 17/10/2012 11:55:27 »
It's hard to see how a fuzzy "electron cloud" could interact with the electromagnetic fields of a photon to promote the electron into a fuzzy cloud with a slightly different shape.

Perhaps a macroscopic  illustration of photon electromagnetism is the rainbow, where light is bent on passing through raindrops.
  • Water has a different permittivity than free space (http://en.wikipedia.org/wiki/Permittivity). This means that the water "resists" the electric field of the photon, and light travels more slowly through water, causing refraction.
  • A similar effect happens for materials which have a different permeability than free space (http://en.wikipedia.org/wiki/Permeability_%28electromagnetism%29), only this time it is the magnetic field of the photon which is affected.
  • So light is an electromagnetic effect, because the velocity of the photons are affected by the permittivity and permeability of the medium they are passing through.

Or perhaps we can see electromagnetism by blowing it up from the quantum domain to a more familiar macroscopic scale, where the electrons are constrained to known paths instead of fuzzy clouds?
  • Instead of protons jiggling inside an atomic nucleus and producing gamma rays (photons with very high energy)
  • ...or an electron jiggling inside an atom and producing visible light
  • ...or a molecule changing its rotation and emitting infra-red light (photons with slightly lower energy)
  • How about electrons oscillating in a coil of insulated wire and producing radio waves (photons with a very low energy)?

You can detect the radio wave photons in two main ways:
  • With a coil of wire - the oscillating magnetic field of the photons induces an oscillating current in the coil of wire which is picked up by the radio receiver
  • With a "Rabbit-Ears" antenna (similar to a TV antenna), where the electric field of the photons induces an oscillating voltage between the two wires, which is picked up by the radio receiver.
  • This experiment courtesy of Hertz, Marconi etc  illustrates the Transverse Electromagnetic Field nature of electromagnetism
« Last Edit: 17/10/2012 12:10:52 by evan_au »
 

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Re: Do force-carrying particles exist?
« Reply #31 on: 17/10/2012 11:55:27 »

 

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