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Cheap Astronomy
2015-Oct-25, 10:48 AM
In my rudimentary understanding of things, gravity is mediated by spacetime curvature. However, I understand there is also a particle-based explanation where consistent mass-mass attraction derives from the even (2) integer-spin of the graviton. Nonetheless, the spacetime curvature story (that I'm going to called a 'field-based explanation') generally seems to be favoured.

I understand the attraction/repulsion interactions between charged particles is mediated by the odd (1) integer spin of the photon. So, I am wondering then if there is also an electromagnetic 'field-based explanation' for the attraction of +ve and -ve charged particles (and the repulsion of like-charged particles). I assume such a field-based explanation is generally not favoured, since I have never heard of it, but am curious to know if such an idea has been postulated in the scientific literature.

Hope you get the gist of what I'm asking.

Thanks,

Steve

Shaula
2015-Oct-25, 12:23 PM
I think you have it the wrong way around for EM theory - the field theory came first. The particle based theory is QED and wasn't put together until the 50/60, whereas Maxwell's equations (which are field based) have been around for nearly a hundred years more.

And even then modern theories actually treat these particles as excitations in an underlying quantum field (which is different to a classical field).

ShinAce
2015-Oct-25, 02:02 PM
Consider that nuclear decay is also mediated by a spin-1 boson. I don't see how I can there's a repulsive effect to nuclear decay or quark confinement.

Naively, if a graviton exists, it must have an even integer spin. It could be 2, or 4, or 6. Two does make the most sense, even if it doesn't lead to a working theory.

I really enjoyed Feynman's lectures on gravitation when I was in college.
http://www.theory.caltech.edu/~preskill/pubs/preskill-1995-feynman.pdf

As Shaula already pointed out, Maxwell's equations are classical field equations. I've heard Einstein spent many years trying to combine gravity and electromagnetism through field equations. I assume with classical fields.

Cheap Astronomy
2015-Nov-10, 10:08 AM
Alas, I failed to fully elaborate that I was looking for an analogy to spacetime curvature. I have heard of magnetic fields before - that wasn't really the issue.

Cheap Astronomy
2015-Nov-10, 10:57 AM
This person gets close to what I was asking about:

You have most likely seen a picture of how the sun "bends" space-time and creates curvature in the field. You can use the same image to visualize how charges "bend" the electromagnetic field. For instance let's say that a negative charge would bend the field downwards - like the sun would space-time - and a positive charge would have the opposite effect and bend the field upwards. In a sort of volcano-like fashion perhaps =) ... Now. The field does not like to be bent. The default state of any field is uncurved, and any curvature in the field will always result in a force trying to even the field out. Many things in nature work like this, always striving for it's "normal state" or the most energy-efficient one. So. When two charges are close enough to each other, their fields will interact. Two of opposite charge will neutralize the field in between the charges resulting in a net "external pressure" pushing them together. Two like charges will instead add more stress to the field in between them resulting in a net "internal pressure" pushing them apart. Perhaps this is a bit harder to visualize. But whether you can visualize it or not doesn't matter. The important thing to understand is that there is a very fundamental principle of nature at work here.

Reference https://www.physicsforums.com/threads/why-do-opposite-charges-attract-and-like-charges-repel.176027/