290:
the same. So without a clear distinction between a group's finite and infinitesimal elements, there's a tendency to explain spin reps with lots of hand-waving and physical nonsense. The truth is that we are exploiting the fact that reps in QM are inherently projective (since a vector and any multiple are physically indistinguishable). So we can pass to the double cover of SO(3) which is SU(2). But this description is likely to be lost on physicists . The pic is misleading with respect to the topology, but is the only (non-trivial) dimension in which a visual depiction of an entire group and its double-cover is possible.
84:
74:
53:
22:
289:
Fair enough... Basically my goal is to help physicists gain some intuition for spin reps. Having a very clear feeling for the difference between SO(3) and SU(2) is important, and it is equally important to understand why this difference is neglected. Obviously the problem is that their algebras are
162:
The "Set up" section has a bit of an oversight in it. It talks about definite forms and double covers of their special orthogonal group, but then when it gets to the case of indefinite forms it does not describe the analogous construction. The fundamental group of these special orthogonal groups
198:
looks like it could be relevant, especially the section on the
Clebsch-Gordan decomposition. Also there is some duplication with that article, which may not be a bad thing. Although I don't really have much of a grand vision for how this article and that one should look.
163:
isn't just cyclic anymore so you have to supply additional details to single-out a canonical 2-sheeted covering space. If I edited the page I'd probably go wild and change much of the exposition so I'd rather just leave it to the original authors.
213:
Some overlap is inevitable, as the articles concern closely related objects. The
Clebsch-Gordan decomposition is essentially covered by the section "Symmetry and the tensor square", although the latter could be expanded to make this more explicit.
140:
432:
402:
357:
404:. Does this happen in the same way as if we used the form to define a Clifford algebra? The latter construction uses the form, but I thought that the construction of
480:
130:
106:
272:
The picture is missleading. dim 1 is the only dimension in which spin is not simply connected, but this is one of the main proberties of spin.
475:
97:
58:
306:
249:
204:
461:
443:
269:
This article is about the spin representation and not the spin group. Probably the picture would clarify something there.
33:
200:
216:
184:
39:
83:
294:
237:
298:
276:
241:
21:
302:
280:
245:
105:
on
Knowledge. If you would like to participate, please visit the project page, where you can join
407:
377:
332:
89:
233:
Hi there, I added the pic in the intro in the hopes of helping readers visualize this concept.
73:
52:
457:
439:
168:
469:
453:
435:
362:
I got lost (among other places) where in says that the quadratic form identifies
448:
I mean something like in the case of the Dirac algebra where the Lie algebra of
102:
310:
284:
253:
220:
208:
188:
172:
79:
164:
195:
15:
452:
can be formed by taking commutators of the Dirac matrices.
317:
182:
Any thoughts on what else needs to go in this article?
410:
380:
335:
101:, a collaborative effort to improve the coverage of
426:
396:
351:
8:
47:
415:
409:
385:
379:
340:
334:
49:
19:
7:
95:This article is within the scope of
38:It is of interest to the following
14:
481:Mid-priority mathematics articles
115:Knowledge:WikiProject Mathematics
118:Template:WikiProject Mathematics
82:
72:
51:
20:
135:This article has been rated as
462:20:08, 11 September 2012 (UTC)
444:20:04, 11 September 2012 (UTC)
189:09:00, 13 September 2008 (UTC)
1:
173:17:57, 17 February 2024 (UTC)
109:and see a list of open tasks.
476:B-Class mathematics articles
427:{\displaystyle \wedge ^{2}V}
397:{\displaystyle \wedge ^{2}V}
352:{\displaystyle \wedge ^{2}V}
497:
311:18:19, 26 March 2011 (UTC)
285:21:34, 20 March 2011 (UTC)
254:00:36, 15 March 2011 (UTC)
194:Some of the stuff over at
221:20:22, 15 June 2009 (UTC)
209:23:49, 14 June 2009 (UTC)
134:
67:
46:
141:project's priority scale
98:WikiProject Mathematics
428:
398:
353:
28:This article is rated
429:
399:
354:
408:
378:
333:
121:mathematics articles
229:So I added a pic...
424:
394:
349:
90:Mathematics portal
34:content assessment
314:
297:comment added by
257:
240:comment added by
155:
154:
151:
150:
147:
146:
488:
433:
431:
430:
425:
420:
419:
403:
401:
400:
395:
390:
389:
358:
356:
355:
350:
345:
344:
313:
291:
256:
234:
123:
122:
119:
116:
113:
92:
87:
86:
76:
69:
68:
63:
55:
48:
31:
25:
24:
16:
496:
495:
491:
490:
489:
487:
486:
485:
466:
465:
411:
406:
405:
381:
376:
375:
360:
336:
331:
330:
292:
263:
261:removed the pic
235:
231:
180:
160:
120:
117:
114:
111:
110:
88:
81:
61:
32:on Knowledge's
29:
12:
11:
5:
494:
492:
484:
483:
478:
468:
467:
423:
418:
414:
393:
388:
384:
359:
348:
343:
339:
316:
274:
273:
270:
262:
259:
230:
227:
226:
225:
224:
223:
201:Sławomir Biały
179:
176:
159:
156:
153:
152:
149:
148:
145:
144:
133:
127:
126:
124:
107:the discussion
94:
93:
77:
65:
64:
56:
44:
43:
37:
26:
13:
10:
9:
6:
4:
3:
2:
493:
482:
479:
477:
474:
473:
471:
464:
463:
459:
455:
451:
446:
445:
441:
437:
421:
416:
412:
391:
386:
382:
373:
369:
365:
346:
341:
337:
328:
324:
320:
315:
312:
308:
304:
300:
296:
287:
286:
282:
278:
271:
268:
267:
266:
260:
258:
255:
251:
247:
243:
239:
228:
222:
219:
218:
212:
211:
210:
206:
202:
197:
193:
192:
191:
190:
187:
186:
177:
175:
174:
170:
166:
157:
142:
138:
132:
129:
128:
125:
108:
104:
100:
99:
91:
85:
80:
78:
75:
71:
70:
66:
60:
57:
54:
50:
45:
41:
35:
27:
23:
18:
17:
449:
447:
371:
367:
363:
361:
326:
322:
318:
293:— Preceding
288:
275:
265:Removed it:
264:
236:— Preceding
232:
217:Geometry guy
215:
185:Geometry guy
183:
181:
161:
137:Mid-priority
136:
96:
62:Mid‑priority
40:WikiProjects
434:does not.
112:Mathematics
103:mathematics
59:Mathematics
470:Categories
178:What else?
299:Sukarsono
277:MamboKurt
242:Sukarsono
158:Oversight
307:contribs
295:unsigned
250:contribs
238:unsigned
454:YohanN7
450:so(3;1)
436:YohanN7
374:) with
139:on the
30:B-class
196:spinor
36:scale.
458:talk
440:talk
329:) =
303:talk
281:talk
246:talk
205:talk
169:talk
165:Rybu
131:Mid
472::
460:)
442:)
413:∧
383:∧
364:so
338:∧
319:so
309:)
305:•
283:)
252:)
248:•
207:)
171:)
456:(
438:(
422:V
417:2
392:V
387:2
372:C
370:,
368:n
366:(
347:V
342:2
327:C
325:,
323:n
321:(
301:(
279:(
244:(
203:(
167:(
143:.
42::
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.