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Timeline for Nature of Spin in QFT

Current License: CC BY-SA 4.0

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Feb 13, 2019 at 18:22 comment added CSnowden I'll try to rephrase my question. Is the symmetry expressed by the group SL(2,C) a property of the specific wave function of the electron matter field (in Hilbert space) - in that sense the answer to my original, broad question would be that intrinsic spin is more a property of the excitation of the electron matter field, but more highly structured than my original basic statement about being asymmetric.
Feb 13, 2019 at 9:13 comment added InertialObserver @CSnowden If you are leaning QFT, learning this terminology is necessary for a complete understanding.. I take it you are at least almost graduated or are in grad school.. If not, then considering QFT to understand spin is probably not the best idea
Feb 13, 2019 at 3:44 comment added CSnowden Can you please translate from the formal mathematics (which I am not able to follow) to the conceptual basis?
Feb 12, 2019 at 22:35 history edited InertialObserver CC BY-SA 4.0
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Feb 12, 2019 at 22:35 comment added InertialObserver I think I see.. So the Poincare group is made up of these finite dimensional irreps, but it itself is infinite dimensional (unitary) representation, is what I'm gathering
Feb 12, 2019 at 22:27 comment added ACuriousMind It is irreducible. It is just not unitary, and it doesn't have to be - only the quantum space of states needs a unitary rep.
Feb 12, 2019 at 22:23 comment added InertialObserver I see.. but then how can we say that the (1/2,0) spinor is an irrep of the PG if it’s only dimension 2, or is that wrong too?
Feb 12, 2019 at 22:18 comment added ACuriousMind The latter. A chiral spinor field lives in two dimensions, its particle states live in an infinite-dimensional Hilbert space. It is the latter space upon which a unitary representation exists.
Feb 12, 2019 at 22:17 comment added InertialObserver In what sense exactly are those reps infinite dimensional? My understanding was that a chiral spinor lives in a two dimensional complex space. Or are you saying that is the case, but that’s not a unitary representation of the PG?
Feb 12, 2019 at 19:29 comment added ACuriousMind There's a bit of terminological confusion in this answer: The unitary representations of the Poincaré group are all infinite-dimensional and not the finite-dimensional representations denoted by a pair of half-integers $(s_1,s_2)$ you talk about later.
Feb 12, 2019 at 0:45 history edited InertialObserver CC BY-SA 4.0
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Feb 11, 2019 at 22:40 history answered InertialObserver CC BY-SA 4.0