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advanced_tools:spinors [2018/03/30 14:50] jakobadmin [Concrete] |
advanced_tools:spinors [2022/09/07 21:52] (current) 147.92.69.196 [FAQ] |
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<tabbox Intuitive> | <tabbox Intuitive> | ||
- | A spinor is a mathematical object similar to a [[basic_tools:vector_calculus|vector]]. However, while a vector points in some spatial direction, like, for example, in the direction of the north pole, a spinor points in a direction in an [[advanced_tools:internal_symmetries|internal space]]. | + | A spinor is a mathematical object similar to a [[basic_tools:vector_calculus|vector]]. However, while a vector points in some spatial direction, like, for example, in the direction of the north pole, a spinor points in a direction in an [[advanced_tools:internal_symmetry|internal space]]. |
A curious property of a spinor is that if you rotate it by 360° it isn't the same but get's a minus sign. Only after a rotation by 720° a spinor is again the same. In contrast a vector is completely unchanged if you rotate it by 360°. | A curious property of a spinor is that if you rotate it by 360° it isn't the same but get's a minus sign. Only after a rotation by 720° a spinor is again the same. In contrast a vector is completely unchanged if you rotate it by 360°. | ||
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* A nice introduction is [[https://arxiv.org/abs/1312.3824|An introduction to spinors]] by Andrew M. Steane | * A nice introduction is [[https://arxiv.org/abs/1312.3824|An introduction to spinors]] by Andrew M. Steane | ||
+ | * [[http://www.weylmann.com/spinor.pdf|A Child’s Guide to Spinors]] by William O. Straub | ||
* See also http://www-personal.umich.edu/~williams/notes/spinor.pdf | * See also http://www-personal.umich.edu/~williams/notes/spinor.pdf | ||
* https://users.physics.ox.ac.uk/~Steane/teaching/rel_C_spinors.pdf | * https://users.physics.ox.ac.uk/~Steane/teaching/rel_C_spinors.pdf | ||
* https://physics.stackexchange.com/questions/74682/introduction-to-spinors-in-physics-and-their-relation-to-representations/112041#112041 | * https://physics.stackexchange.com/questions/74682/introduction-to-spinors-in-physics-and-their-relation-to-representations/112041#112041 | ||
+ | ---- | ||
- | **Things to take note of:** | + | **Things to take care of:** |
<blockquote>Representing the u, as vectors is a heuristic oversimplification though, and in fact is not really correct, as operations like spinor addition work a little differently than vector addition. (See Winter 3.) However, temporarily visualizing them as such can aid in our understanding of how they and spin behave, relative to the at-rest coordinate system, for varying particle velocities.<cite>page 99 in [[ftp://srdconsulting.com/USB_BackUp/Data/Articles/QFT/StudentFriendlyQFT/SF_QFT_Chap04.pdf|Student Friendly Quantum Field Theory]], by R. Klauber</cite></blockquote> | <blockquote>Representing the u, as vectors is a heuristic oversimplification though, and in fact is not really correct, as operations like spinor addition work a little differently than vector addition. (See Winter 3.) However, temporarily visualizing them as such can aid in our understanding of how they and spin behave, relative to the at-rest coordinate system, for varying particle velocities.<cite>page 99 in [[ftp://srdconsulting.com/USB_BackUp/Data/Articles/QFT/StudentFriendlyQFT/SF_QFT_Chap04.pdf|Student Friendly Quantum Field Theory]], by R. Klauber</cite></blockquote> | ||
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<cite>[[https://arxiv.org/abs/1312.3824|An introduction to spinors]] by Andrew M. Steane</cite> | <cite>[[https://arxiv.org/abs/1312.3824|An introduction to spinors]] by Andrew M. Steane</cite> | ||
</blockquote> | </blockquote> | ||
+ | |||
+ | <blockquote>No one fully understands spinors. Their algebra is formally understood, but their geometrical significance is mysterious. | ||
+ | In some sense they describe the ‘‘square root’’ of geometry and, just as understanding the concept of $\sqrt{-1}$ took centuries, | ||
+ | the same might be true of spinors. <cite>Sir Michael Atiyah</cite></blockquote> | ||
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<cite>Student Friendly Quantum Field Theory by Klauber</cite></blockquote> | <cite>Student Friendly Quantum Field Theory by Klauber</cite></blockquote> | ||
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+ | * [[https://geocalc.clas.asu.edu/pdf/SPINORPM.pdf| Spinor Particle Mechanics]] by David Hestenes | ||
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