Talk:Circle group/Archive 1

Latest comment: 11 years ago by Milez in topic What is U(1)?
Archive 1

Examples

Could somebody give well-known examples of different circle groups? This is a hard article to get into if you're not familiar with the terminology, but I know this concept is well-used...72.253.230.202 (talk) 17:32, 23 October 2009 (UTC)

What is U(1)?

I got here from "Thus, for example, the electric charge is the generator of the U(1) symmetry of electromagnetism." in http://en.wiki.x.io/wiki/Charge_(physics), but I have no idea how to relate U(1) to anything on this page; either explain U(1) or recreate the U(1) page. —Preceding unsigned comment added by 202.63.53.14 (talk) 01:37, 28 November 2010 (UTC)

I found these clearly written notes explaining U(1) from a mathematical physics point of view: http://www.math.columbia.edu/~woit/QM/charge.pdf. If you compare them to this Circle Group article I think you will see the connection (U(1) basically is the set of complex numbers of unit magnitude i.e. the unit circle in the complex plane). I agree this article should mention U(1) explicitly. Milez (talk) 19:41, 31 October 2013 (UTC)