Well, technically...
Guy: “What is light?”
Chap: “Well, it’s what makes something visible…”
Bloke: “Well, technically, you can have light outside the visible spectrum, like ultraviolet and infrared…”
Lass: “Well, technically, light is a photon, so it’s a wave in the electromagnetic field…”
Dude: “Well, technically, a photon is a quantized wave in the electromagnetic field…”
Fellow: “Well, technically, a photon is the gauge boson associated with the U(1) symmetry of the Dirac equation…”
Guy: “Well, technically, a photon is the gauge boson associated with the local U(1) symmetry of the Dirac equation…”
Fellow: “Well, technically, the photon field arises from the subgroup of SU(2)ʟ × U(1)ʏ that leaves the Higgs ground state invariant...”
Chap: “Well, technically, a photon is a derivative…”
Guy: “Well, technically, a photon is the modification to make the derivative gauge invariant, kinda like the other guy said…”
Lass: “Well, technically, a photon is a representation of the Poincaré group…”
Dude: “Well, technically, a photon is an irreducible representation of the Poincaré group…”
Fellow: “Well, technically, a photon is a basis element of an irreducible representation of the Poincaré group…”
Guy: “Well, technically, a photon is a massless spin-1 particle in four dimensions…”
Chap: “Well, technically, the Poincaré group is already in four dimensions anyhow so that was an unnecessary technicality...”
Bloke: “Well, technically, the Poincaré group can be extended to ISO(1,d-1) for any d…”
Lass: “Well, technically, d has to be greater than 2, otherwise you’re degenerate…”
Dude: “You’re degenerate… Oh, whoops… I meant, well, technically, a photon is an emergent phenomenon that comes from the underlying updating rules of a hypergraph…”
Fellow: “Well, technically, a photon is a specific component of the unified gauge potential ϖ associated with the Spin(4) subgroup of the structure group, and these gauge components are pulled back onto our 4D spacetime through observation embeddings…”
Guy: “Well, technically, we were talking about light, and the etymology of light is that of lēoht, which is Old English, and it means brightness…”
Chap: “Well, technically, it’s Proto-Germanic, Leuhtam, but still means brightness, so you at least got one thing correct, finally…”
Dude: “Well, technically, even further back, Proto-Indo-European (PIE): Leuk-—root meaning "light, brightness" (cognates: Latin lux, Greek leukos) and then Greek: Leukos—meaning "bright, shining, white." and then Latin: Lux—meaning "light" (daylight, illumination)…”
Lass: “Well, apparently, it’s even further to Sanskrit with Rochis meaning brightness…”
Dude: “Well, technically, you weren’t supposed to say ‘apparently’ and you broke the rhythm…”
Fellow: “Well, technically, the order of that etymology is Old English, then Latin, then Proto-Germanic, then Greek, then Sanskrit, then Proto-Indo-European…”
Guy: “Well, technically, light is the absence of darkness, and darkness is defined as wickedness…”
Chap: “Well, technically, wickedness is a holomorphic object on twistor space…”
Bloke: “Well, technically, we’re back to photons, and that’s a cohomology class in H¹(T, O(-2)), where T is twistor space and O(-2) is a holomorphic line bundle encoding the helicity of the massless spin-1 field…”
Lass: “Well, technically, a photon is a boundary excitation on a conformal field theory…”
Dude: “Well, technically, a photon is a self-entangled vortex of an electron-positron pair, potentially involving a wormhole substructure within the T4G framework…”
Bloke: “Well, technically, the photon is represented by a string-localized field, which corresponds to a zero-mass, infinite-spin representation of the Poincaré group…”
Fellow: “Well, technically, a photon is a massless particle that travels along null geodesics…”
Guy: “Well, technically, a graviton and other hypothetical particles may also be massless and travel along null geodesics, so…”
Chap: “Well, technically, a photon is the superpartner of a photino…”
Bloke: “Well, technically, a photon is the first excited state of an open string, typically appearing in the Neveu-Schwarz sector…”
Lass: “Well, technically, you’ve been saying that for 50 years…”
Dude: “Well, technically, I haven’t said it for 50 years, otherwise I wouldn’t be able to breathe due to only exhaling…”
Fellow: “Well, technically, you’re just being pedantic…”
Dude: “Well, technically, I was just being punctilious…”
Chap: “Well, technically, you were demonstrating an obsession with technical accuracy and nitpicking over increasingly finer details, to the point of missing the bigger picture, which is characteristic of being pedantic…”
Bloke: “Well, technically, your accusation was not a technical point but an opinion…”
Dude: “Okay, this is getting out of hand.”
Chap: “It’s not, it’s perfectly within hand.”
Fellow: “You’re a fool.”
Guy: “And you aren’t using your entire brain.”
Fellow: “Yeah, that’s okay, because humans only use 10 percent of their brains…”
Bloke: “…”
...: (each person looks at each other)
...: (10 seconds of silence)
Fellow: “…”
Guy: (looks at Dude) “Don’t you dare—”
Dude: “Well, technically…”
PS: Well, technically, I should thank Bijou Smith, Lucas Cardoso, and Richard Behiel for their insights.
This was enjoyable!
I am wondering if all those concepts of "photon" are valid? Curt, did you think any of them were not technically correct? ;-)
Even,
Guy: “Well, technically, light is the absence of darkness, and darkness is defined as wickedness…”
Chap: “Well, technically, wickedness is a holomorphic object on twistor space…”
had me laughing, but sure, why not extend the notion of "light" to metaphor.
Seriously, what I was interested in is the shear volume of how many alternatives were offered. Given there is an underlying reality to a physical photon, then what we have here are many languages or dialects that mathematics provides for describing the same thing. Hardly profound (it is "just Langlands" or "just Erlangen"). And yet I always think it is profound.