Photon - Revision history

Tom: /* Photons Travel through Space */

2025-01-11T01:04:23Z

‎Photons Travel through Space

Tom: /* Context */

2023-12-26T20:29:39Z

‎Context

Tom: /* Momentum */

2023-12-24T02:32:44Z

‎Momentum

Tom: /* Photon Smearing */

2023-12-22T17:59:40Z

‎Photon Smearing

Tom: /* How does absorption of virtual photons "smear" a particle? */

2023-03-21T00:31:53Z

‎How does absorption of virtual photons "smear" a particle?

Tom: /* Full Title */

2023-03-18T19:32:42Z

‎Full Title

Tom: /* Full Title */

2023-03-18T19:31:58Z

‎Full Title

Tom: /* Context */

2023-03-18T19:30:13Z

‎Context

Tom: /* Matter */

2023-03-18T19:25:07Z

‎Matter

Tom: /* Matter */

2023-03-18T19:23:48Z

‎Matter

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 Now, if you release photons one at a time, and there’s no other source of photons, and you detect one at the detector, you can infer that it passed from the source to the detector, but you can’t be 100% sure of that - it could have hit an air molecule along the way, gotten absorbed, and another photon could have gone off in some odd direction, only to be absorbed and replaced by a third photon that happens to go the detector. This would usually be unlikely, but it is a possible sequence of events. So there’s always that slim chance that no photon traversed a particular volume, even if it’s in the “obvious path.”
-The emission of light from an excited atom is a symmetrical process which radiates in all directions, to the same extent as a small dipole antenna would radiate. But QM tells us that when we hear a click in a photodetector, it means that the photon has been captured. The wave function which was spreading out spherically has suddenly become localized at a single point. It’s called “collapse of the wave function”. There is no way to say with any certainty what the "path" was followed by the photon from emission to absorption actual was. In some weird sense it "followed" all paths at once.
+The emission of light from an excited atom is a symmetrical process which radiates in all directions, to the same extent as a small dipole antenna would radiate. But QM tells us that when we hear a click in a photodetector, it means that the photon has been captured. The wave function which was spreading out spherically has suddenly become localized at a single point. It’s called “collapse of the wave function”. There is no way to say with any certainty what the "path" was followed by the photon from emission to absorption actual was. In some weird sense it "followed" [[All Possible Paths]] at once.
 According to the current formalism light travels through empty space, which has no physical properties, no conductivity. Light is electromagnetism energy/radiation, but energy does not flow without potential differences like electricity doesn’t flow in an open circuit. This was a huge conceptual problem the Wheeler-Feynman absorption theory attempted to address but ran into some major [[Causality]] issues.

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 need to enable displaystyle for this to work
-{\displaystyle E^{2}=p^{2}c^{2}+m^{2}c^{4}~.}{\displaystyle E^{2}=p^{2}c^{2}+m^{2}c^{4}~.}
+ E2 = p2c2 + m2c4
-The energy and momentum of a photon depend only on its frequency ({\displaystyle \nu }\nu ) or inversely, its wavelength (λ):
+The energy and momentum of a photon depend only on its frequency &nu; or inversely, its wavelength (λ):
 {\displaystyle E=\hbar \,\omega =h\,\nu ={\frac {\,h\,c\,}{\lambda }}}{\displaystyle E=\hbar \,\omega =h\,\nu ={\frac {\,h\,c\,}{\lambda }}}

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 ===Momentum===
-Physics literature calls Bosons, including Photons, force carriers. This is misleading. In reality all a photon has been observed to carry is momentum.
+Physics literature calls Bosons, including Photons, force carriers. This is misleading. In reality all a photon has been observed to carry (beside phase and energy) is momentum.
 ===Photon Smearing===

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 Some researchers<ref>M. S. El Naschie, ''A Unified Newtonian-Relativistic Quantum Resolution of the Supposedly Missing Dark Energy of the Cosmos and the Constancy of the Speed of Light''  https://doi.org/10.1016/j.physletb.2014.03.020</ref> do not assume a constant speed for light, but rather just that the expected speed is the constant value c.
 ===Photon Smearing===
 * [https://indico.jlab.org/event/362/contributions/5786/attachments/4894/6111/Collaboration_Meting_pjlin_20200201.pdf Exclusive 𝜋0-production Cross Section Extraction] Po-Ju Lin 2020-02-01
 ===[https://physics.stackexchange.com/questions/476296/how-does-absorption-of-virtual-photons-smear-a-particle How does absorption of virtual photons "smear" a particle?]===

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 Self-energy is only appearing second order in alpha in perturbation theory. At all energies we can achieve, alpha is very small (1/137). At very high energies the effect of the self-energy would become more important.
-our calculations/models from which the not yet corrected values come are approximating more things, s.t. the uncertainty is much bigger than this correction. The hydrogen atom is a two-body problem and analytically solvable. Helium already needs some approximations to be made/numerical calculations to be solved.
+our calculations/models from which the not yet corrected values come are approximating more things, s.t. the [[Uncertainty]] is much bigger than this correction. The hydrogen atom is a two-body problem and analytically solvable. Helium already needs some approximations to be made/numerical calculations to be solved.
 ==Matter==

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 ==Full Title==
-A [[Photon]] is a quantum of energy typically emmited by one Electron and absorbed by another.
+A [[Photon]] is a quantum of energy typically emitted by one Electron and absorbed by another. (The most common scenario.)
 * See [[Eventful_Universe#Life_Cycle of a Photon|Eventful Universe, the Lifecycle of a Photon]]

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 A [[Photon]] is a quantum of energy typically emmited by one Electron and absorbed by another.
-* See [[Eventful_Universe#Life_Cycle of a Photon]]
+* See [[Eventful_Universe#Life_Cycle of a Photon|Eventful Universe, the Lifecycle of a Photon]]
 ==Context==

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 where k is the wave vector, where
-k ≡ |k| =
+ k ≡ |k| =  2π /λ  is the wave number, and
-π
+ ω ≡ 2 π ν   is the angular frequency, and
+ ħ ≡ h/ 2π    is the reduced Planck constant.
 Since p points in the direction of the photon's propagation, the magnitude of its momentum is

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 ==Matter==
-The working assumption of the "big bang" is that in the beginning there was energy, lots of it, but no matter. We know that two photons can collide and product one matter and one anti-matter particle.<ref> Karen McNulty Walsh, Peter Genzer, ''Collisions of Light Produce Matter/Antimatter from Pure Energy'' (2021-06-21) Brookhaven National Laboratory https://www.bnl.gov/newsroom/news.php?a=119023</ref> But now the known universe of matter has no detectable antimatter particles. So, how can it be that our universe consists of matter and not antimatter. Well, if there was any difference in the longevity of matter over antimatter, not matter how small that difference might be, matter would eventually prevail. So that's what must have happened using Occam's razor as the proof.
+The working assumption of the "big bang" is that in the beginning there was energy, lots of it, but no matter. We know that two photons can collide and product one matter and one anti-matter particle.<ref> Karen McNulty Walsh, Peter Genzer, ''Collisions of Light Produce Matter/Antimatter from Pure Energy'' (2021-06-21) Brookhaven National Laboratory https://www.bnl.gov/newsroom/news.php?a=119023</ref> But now the known universe of matter has no detectable antimatter particles. So, how can it be that our universe consists of matter and not antimatter. Well, if there was any difference in the longevity of matter over antimatter, no matter how small that difference might be, matter would eventually prevail. So that's what must have happened using Occam's razor as the proof.
 ==References==
 [[Category: Physics]]