Exploring the Dimensions of a Photon: Understanding its Size and Structure

[Salman2]

From this book: Lecture Notes in Physics: The Nature of the Elementary Particle, 1978. Malcolm H. MacGregor, it is stated (in quotes):

"The particle properties of the photon emerge most clearly from Compton scattering, in which a high-energy photon makes a billiard-ball type of collision with an electron, and hence delivers its energy and momentum into a volume that has dimensions on the order of 10^-11 cm (the Compton wavelength of the electron)."

The "particle" aspect of the photon from Compton scattering experiments represents a "MeV photon" compared to an "optical-frequency wave photon" that is about 10^6 times larger in dimension.

"In dealing with the photon, we must take into account both its wave aspects and its particle aspects. But since these two aspects differ dimensionally by many orders of magnitude, they are in a practical sense separate entities, so that we can discuss the wave properties of the photon without having to consider its particle properties, and vice versa."

 

[heterotic_]

From this book: Lecture Notes in Physics: The Nature of the Elementary Particle, 1978. Malcolm H. MacGregor, it is stated (in quotes):

"The particle properties of the photon emerge most clearly from Compton scattering, in which a high-energy photon makes a billiard-ball type of collision with an electron, and hence delivers its energy and momentum into a volume that has dimensions on the order of 10^-11 cm (the Compton wavelength of the electron)."

The "particle" aspect of the photon from Compton scattering experiments represents a "MeV photon" compared to an "optical-frequency wave photon" that is about 10^6 times larger in dimension.

"In dealing with the photon, we must take into account both its wave aspects and its particle aspects. But since these two aspects differ dimensionally by many orders of magnitude, they are in a practical sense separate entities, so that we can discuss the wave properties of the photon without having to consider its particle properties, and vice versa."

Realistically, that is only a good conclusion when you discuss the outcomes the two produce independent of each other.

However, we are discussing bridging the gap, so saying not to, is just illogical. If we think about what a wave really is, we envision that oscillating line we produce with technology, or a ripple from a linear perspective so we see the amplitude of a physical wave. The problem with that is that it is a perspective, it isn't the entirety of the actual wave itself. It is only a description from a reference point, and requires ignoring the rest of the "picture", as it were. It is also representing a point · moving across an oscillating line from the "side", but a straight line from the "top". You really cannot picture the wave that way, it is merely a representation to represent wavelength and amplitude, based on what we observe as physical waves from a sideview, like the water oscillating in a ripple.I think a "real view" of the wave would produce a different picture more like:

O>·<O>·<O>·<O>·<O>·<O

With that (granted, think of the swells with more of the same wave length of a particular frequency), we could even find the radii of all the "sizes" that the photon takes on spherical calculations of each moment of the swell.

 

[Pinewater]

Just an fyi, in scientific literature the 'size' of a photon generally refers to its coherence length. (which is definitely NOT to say that this is the only correct way to think about a photon's size!)

You can look up coherence length on the web, but I understand it best in the context of an interferometer. In this setting, the coherence length is the maximum distance that a single photon can travel and still interfere with itself (which means that it produces an interference pattern at the screen).

 

[Pianoasis]

I think the two-slit expirements should be done in a vacuum. The molecules in the air obviously cause some interference with the photons natural behavior. In fact it could be the only reason the photons act like a particle. The photon waves hit the molecules in the air, send them along the photon wave's path, and hit the screen in the appearance of a particle. If these tests were to be done in a vacuum we would have much clearer results.

 

[Vanadium 50]

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