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Aug 15, 2010 at 0:14 history edited Jess Riedel CC BY-SA 2.5
added 681 characters in body
S Jul 21, 2010 at 19:03 vote accept Jess Riedel
S Jul 21, 2010 at 19:02 vote accept Jess Riedel
S Jul 21, 2010 at 19:03
Jul 21, 2010 at 19:01 vote accept Jess Riedel
S Jul 21, 2010 at 19:02
Jul 21, 2010 at 1:39 answer added Willie Wong timeline score: 5
Jul 20, 2010 at 22:44 comment added Daniel Litt Ah yup that's what I meant.
Jul 20, 2010 at 22:37 answer added Helge timeline score: 2
Jul 20, 2010 at 22:32 comment added Jess Riedel @Wille: whoops, you're right.
Jul 20, 2010 at 22:22 comment added Jess Riedel @Helge: Yes, I figured this was a standard result from random matrix theory. Unfortunately, I'm really interested in matrices constructed like $S$. I was including $R$ for contrast.
Jul 20, 2010 at 22:17 comment added Willie Wong @Jesse, I suspect Daniel meant $[0,1/2]\times (1/2,1]$ and vice versa.
Jul 20, 2010 at 22:10 history edited Jess Riedel
Removed bad tag
Jul 20, 2010 at 22:09 comment added Jess Riedel The tag has been removed. Thanks for the advice.
Jul 20, 2010 at 22:08 comment added Jess Riedel But Daniel, isn't true that if $f(x,y) = 1$ on $[0, 1/2]\times [0, 1/2]$ and vanishes otherwise, then $\mathrm{Tr} [\sqrt{S^\dagger S}] = \mathrm{Tr} [S] = d/2$ ? In any case, I agree that the linear behavior of $||S||$ might not survive for carefully chosen $f(x,y)$ (and, of course, for $f=0$), but I think it should be preserved for "most" $f$.
Jul 20, 2010 at 22:00 comment added Helge I guess the first statement should follow from well-known principles. We know where the density of states for i.i.d. matrices converges to, and then the claim follows by integrating $|x|$ against it. The second statement seems more tricky.
Jul 20, 2010 at 21:54 comment added Jess Riedel Maybe not. This is the mathematical part of a quantum information calculation, but I don't really know what the "quantum-algebra" tag is. If someone else agrees that it's not appropriate, I'll happily remove the tag.
Jul 20, 2010 at 21:53 comment added Daniel Litt Note that $||S||=0$ for all $d$ if the support of $f$ is contained in $[0, 1/2]\times [0, 1/2]$ or $[1/2, 1]\times [1/2, 1]$.
Jul 20, 2010 at 21:45 history edited Yemon Choi
added tag
Jul 20, 2010 at 21:45 comment added Yemon Choi Not sure if the "quantum-algebra" tag is appropriate, but I'm not competent to judge...
Jul 20, 2010 at 21:24 history asked Jess Riedel CC BY-SA 2.5