Spinors Definition and 119 Threads

  1. N

    Spinors and spatial coordinates

    I was reading a web page (http://electron6.phys.utk.edu/qm1/modules/m12/spinor.htm) that claims that the state vector of a spin-1/2 particle is completely specified by a two-component spinor, just as the state vector of a spinless particle is completely specified by its components in position...
  2. S

    Explaining Conformal Killing Spinors

    This could have gone in about 4 different forums, so I apologize if I picked the wrong one. I'm wondering if anyone can explain what (conformal) killing spinors are all about. All I can find is that they are sections of the spinor bundle of a spin manifold satisfying: \nabla_\mu \epsilon =...
  3. H

    Martin Kober: The relation of a unified QFT of spinors to the structure of GR

    As suggested by Marcus, I have read the whole paper and decided to start a discussion of Kober's paper by asking a few questions. The paper certaintly presents a very interesting view. Part of it is an extension of Heisenberg's work on unified QFT, that the mass originates from self-interaction...
  4. B

    Dirac Spinors Suck: QFT Calculations with Weyl Spinors

    I think that anyone who has done a course in QFT has had their progress hampered by AT LEAST a month by Dirac Spinors. Why is it that the only sensible way to write the Standard Model down is to use Weyl Spinors, but the only sensible way to do calculations is to use Dirac spinors and...
  5. B

    Action of Clifford-elements on vectors & spinors

    Hi all! I am currently preparing a talk about Clifford algebras and pin/spin-groups. Since half the audience will consist of physicians (as I am myself) I also want to get more into the connection of the mathematical definitions and derivations (as one may find in Baker, "Matrix groups" or...
  6. N

    Spinors in d dimensions and Clifford algebra

    I bought a book on susy and there is a chapter on spinors in d-dimensions. Now, maybe I am extremely dumb but I just can't understand the first few lines! EDIT: I was being very dumb except that I think there is a typo...See below... BEGINNING OF QUOTE Consider a d-dimensional...
  7. J

    Why there are no spinors for GL(n)

    Does anybody know a simple proof of the fact that there are no finite-dimensional extensions of the \textsl{so(n)}-spinor representation to the group of general linear transformations. The proof seems can be based on the well-known fact that when rotated 2\pi a spinor transforms...
  8. M

    Why Do GUT Theories Only Use Left Spinors?

    Why in every single text about GUT theories only the left spinors are used? Why use the conjugate of the spinor instead of the spinor itself? Is it just a another historic definition? Thanks
  9. K

    Is there a relation between GCT and Lorentz invariance?

    I am not sure where to post this question since it involves GR and particle physics but here it goes. I am reading in a book that when coupling a spinor to gravity, one replaces \partial_\mu \psi [/tex] by a covariant derivative D_\mu \psi [/tex] which must transform like a spinor under...
  10. A

    Commuting metric past Dirac spinors?

    I'm wondering how in Peskin & Schroeder they go from i\mathcal{M} = {\overline{v}^s^'} (p^{'}) (-ie\gamma^\mu)u^s(p) \left( \frac{-ig_{\mu\nu}}{q^2} \right) \overline{u}^r (k) (-ie\gamma^\nu) v^{r^{'}} (k) at the bottom of page 131 to (5.1) at the top of 132 which reads i\mathcal{M}...
  11. C

    Are spinors just wavefunctions in the dirac field?

    are spinors just wavefunctions in the dirac field?
  12. M

    Spinor Boosts: Weinberg's QFT Book Insights on Rotation and Momentum Effects

    Weinberg shows in his book on QFT that the effect of a rotation on a massive particle's spin is the same as applying exp(-i \theta J.n) on the state, regardless of particle's momentum. In other words just rotate the spinor in its own representation. This makes calculations very simple. But what...
  13. B

    Lorentz Transformations and Spinors

    Hi, I have a question about spinors If \Lambda is a Lorentz Transformation what is (and how do you show that it is) the spinor representation of the Lorentz group ? I think it has somnething to do with the equivalence transformation S\dagger{\gamma}S=\Lambda\gamma But that is just a...
  14. K

    Eigenblades and the Geometric Algebra of Spinors

    I've been looking into Geometric Algebra approaches to linear transformations and have found it to be MUCH nicer than the conventional matrix approaches for certain kinds of transformations. Moreover, I find it much more intuitive, particularly in its way of dealing with complex numbers. For...
  15. arivero

    Separate normalisation of chiral spinors?

    When solving Dirac equation (for free massive particles) we usually impose normalisation conditions upon the eigenfunction in a single stroke. I am wondering, Is it possible/useful to impose separate normalisation conditions upon the left and right spinors? Should we still have a resolution...
  16. M

    General Relativity and Theory of Spinors

    Be kind with me I am just a dentist; nevertheless I am trying to understand the GR and the Theory of Spinors. In this sense I tried to explore the fundations of the GR and made use of a Taylorisation of the variations of the basis vectors de (with subscript 0, 1, 2 or 3) until the second order...
  17. D

    Proving Spin-1/2 Spinors are Eigenvectors to $\hat S^2$

    Can anyone give me some hints? I need to prove that all spinors to a spin-1/2 particle are eigenvectors to \hat S^2! /Daniel
  18. J

    Understanding Spinors: Not Your Typical Tensor

    What mathematically speaking is a spinor? Why isn't it a tensor? I didn't find the mathworld defintion very useful at all as it describes it as a complex column vector which really tells me nothing especially as we usually think of such an object as a tensor!
  19. T

    Pronouncing Spinors: A Self-Adjoint QM & GR Example

    Self Adjoint very nicely gave me an example when QM doesn't work with GR using something called Spinors which define quantum mechanical particles. i was wondering how exactly is spinors pronounced Is it like spinners umm like the rims lol :) ? Sorry for the odd question, I just don't...
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