Bosons n forces n stuff

Did you transfer out of Physics II on the first day?

>>8262971
No, I sometimes read about this stuff at work when there is nothing to do.

Electric and magnetic fields are components of what's called the curvature of the photon field. Photons are propagating waves ("excitations") in this field, so you always have curvature and thus E & M fields. But if those fields (the curvature) are (is) static, then there are no propagating waves and thus no photons.

You need to change the electric or magnetic fields to create photons. It's really easy and it happens all the time, but they're super low frequency. Changing the fields back and forth a billion times a second (1 GHz) only produces radio waves. You need around 430 trillion back and forth changes in the field every second to see visible light, in that case it would be red.

>>8262993

So yeah if you spun that magnet around at 500 THz or so you'd see some visible light. Of course that's impossible, the thing would be torn apart by centrifugal forces and/or melted long before you got it spinning that fast.

File: magnet.jpg (5KB, 259x279px) Image search: [Google]

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>>8262993
>and thus no photons
What then carries the force in a static field?

>>8263073
idk, maybe there are no forces when absolutely static?

>>8263073
>>8263078
Electromagnetic forces are derived from the interaction of charged matter and the curvature of the photon field. The image you have of forces being entirely reliant upon the absorption of individual photons is a vast simplification. It's very hard to actually visualize what is going on, and I'll admit that I am ignorant of much (not all) of the formal theory. I believe that this confusion comes from the use of virtual photons to mediate the interaction between charges as a mathematical tool. Realistically, you must understand that these are fields which extend over all of space and are coupled together. The behavior of the propagation in the electron field creates disturbances in the photon field (which propagate outward from their source at the speed of light), and a stationary system in the electron field - such as a permanent magnet or stationary group of charges - creates a stable situation in the photon field which directs the behavior of other "free" electrons through it's curvature.

For instance, the electron's magnetic dipole moment is a product of a "tensor coupling" between the electromagnetic field strength and this other special quirk of Dirac theory which is related to spin. Regardless of what the electron is doing, its quantum mechanical spin is curving the photon field around it creating a dipole magnet. That interaction looks like this (providing I get this LaTeX right)
[math]\displaystyle\sigma_{\mu\nu}F^{\mu\nu}[/math]

File: Einstein-Bergmann-1938c.jpg (75KB, 752x444px) Image search: [Google]

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>>8263218
Thanks for the summary.
This 'entity-field' concept plus interaction (although certainly refined) still seems far removed from Einstein's 'structures of the unitary field' vision, despite the common mathematical tools. Still (3D+T), still no ftl, still no unified field. As if the status quo precludes a breakthrough in fundamental physics. I could even think of valid reasons.

I will give a somewhat contemporary and simplified explanation. To better understand electromagnetism you should consider courses in quantum electrodynamics after completing the sufficient prerequisites.

Electromagnetism is due ultimately to the exchange of a mediating massless, spin = 1 (angular momentum in half integer units of ħ) particle called a photon (γ), which acts upon charge. The particles that experience the interaction are charged particles such as electrons (e-), protons (p+), muons (μ-), and charged compositions of pions (π-, π+).

The potential energy (U) is equal to the electromagnetic coupling constant, or charge; (e) squared divided by the distance between the charged particles (r).

The strength of the interaction (α) in natural units, called the fine-structure or Summerfield's constant, is equal to the electromagnetic coupling constant (e) squared devided by 4π, or roughly 1/137. (When ε = c = ħ = 1)

Because the photon is massless, the range is infinite. It "falls off" around U = 1/r, but the terminology one uses is that the range refers to the exponential (coupling constant).


If you do have a background in mathematics and physics, we could discuss electromagnetism more rigorously (the Lagrangian field, Dirac matrices, Lorentz index, anticommutators, etc.) in the framework of QM and QED.

>>8262963
>So if magnetism is due to the electromagnetic force, and photons are the force carriers for the electromagnetic force, does that mean if I put a strong enough magnet in front of my eyes and another behind my head then I will see photons?

You don't need the magnet to see photons, man.

If I take a laser pointer and shine it into my eye, can I see individual photons?