Timeline for What is the significance of Lie groups $SO(3)$ and $SU(2)$ to particle physics?
Current License: CC BY-SA 3.0
16 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 13, 2017 at 12:40 | history | edited | CommunityBot |
replaced http://physics.stackexchange.com/ with https://physics.stackexchange.com/
|
|
| Apr 3, 2015 at 8:50 | comment | added | Selene Routley | @Vectornaut ... social relationships and the learning to be a social animal and the belt - mathematics - is the second great literacy: learning to understand the abstract relationships between things, categories and processes in the World (number encoding two special cases - the relationships of order and size, for example) is what a great deal of nonsocial child's play is directed towards this understanding. A few audience members quizzed me specifically on the belt trick and I felt they grasped the doll version better than my explanations before then and the same seems to go for children too | |
| Apr 3, 2015 at 8:43 | comment | added | Selene Routley | @Vectornaut Many thanks for the kind words. I actually came up with the idea kind of by accident. I was doing the belt trick at my daughter's primary school and at the same time talking a great deal with primary level teachers about the foundations of numeracy. To cut a long story short, I used the belt trick with a doll in a talk I did with some education researchers as a means to be "symbolic" - I liked the idea of uniting a mathematical toy with a social play toy: social play, symbolized by the doll, brings the child to what I call the first great literacy: the understanding of ... | |
| Apr 2, 2015 at 0:53 | comment | added | Vectornaut | The idea of using a doll for the belt trick is fantastic! I've seen lots of kids lose count of rotations while doing the trick, so I'll definitely keep your tip in mind. | |
| Feb 14, 2014 at 4:11 | history | edited | Selene Routley | CC BY-SA 3.0 |
fixed explanation of pions in isospin description
|
| Nov 4, 2013 at 1:14 | comment | added | Selene Routley | @Freeman ....and physical properties will not let it reach, but its an extremely good analogy). In particular, looping the ribbon over the doll with the latter held fixed leads to a path in the same homotopy class: so if you can undo the twist by looping, the doll and ribbon still encode the same member of $SO(3)^\sim \cong SU(2)$. | |
| Nov 4, 2013 at 1:14 | comment | added | Selene Routley | @Freeman If you've not met the universal cover before, a good lecture on it is docstoc.com/docs/28157208/… . If you think about the abstract procedure, you can see that the ribbon in the belt trick encodes a path from the identity to the SO(3) transformation encoded by the doll's orientation in space. Every deformation of the ribbon thus encodes a member of the same homotopy class, so the ribbon itself pretty much encodes THE homotopy class (of course there will be some deformations that the ribbon's elasticity .... | |
| Nov 4, 2013 at 0:36 | comment | added | Selene Routley | @Freeman You might like to check out my demo "Dirac Belt Trick Simulation Showing Double Cover of SO(3) by SU(2)" at Wolfram Demonstrations. | |
| Sep 27, 2013 at 11:36 | history | edited | Selene Routley | CC BY-SA 3.0 |
tidied up Noether's theorem discussion
|
| Sep 27, 2013 at 9:28 | vote | accept | Freeman | ||
| Sep 27, 2013 at 4:28 | history | edited | Selene Routley | CC BY-SA 3.0 |
reworded Feynman paragraph and corrected "the" to "that": everything that transforms compatibly with rotations.
|
| Sep 27, 2013 at 4:05 | history | edited | Selene Routley | CC BY-SA 3.0 |
Checked Feynman quote
|
| Sep 27, 2013 at 3:40 | history | edited | Selene Routley | CC BY-SA 3.0 |
Added more links and optics example
|
| Sep 27, 2013 at 3:40 | comment | added | Selene Routley | @Freeman I've added some more info and links - reworded former answer slightly to add more detail of my thoughts about gauge theory and also added an $SU(2)$, $SO(3)$ example from my day job field. Hope you like it! | |
| Sep 26, 2013 at 15:35 | comment | added | Freeman | Thank you ever so much for this. It is extremely useful, thanks for your intuitive description of the 'double cover' concept. | |
| Sep 26, 2013 at 14:05 | history | answered | Selene Routley | CC BY-SA 3.0 |