June 06, 2004

Technical notes on linear matrix equations

[pdf]: On linear matrix equations

These are technical notes. As the title indicates, they're not terribly likely to cause spontaneous celebrations in the streets, but contain material that may be of interest to people interested in quantum process tomography, the Solovay-Kitaev theorem, or quantum state estimation. Despite the format, these are not intended as a paper, and there's little original content; they are primarily notes about work by other people that I think is interesting.

Posted by Michael Nielsen at June 6, 2004 07:27 AM
Comments

Oooooh, theory of the Matlab's reshape function. Is there overlap here with quaternion theory (some of this look similar, but I need to look some stuff up)? Hmmm.

Posted by: agm at June 6, 2004 10:51 AM

I think the link needs modification: it probably works from the main page, but from the archive page for this entry (which I accessed it from) the link doesn't work because it's relative and thus has an extra /archive prepended to it.

Posted by: Suresh at June 6, 2004 11:00 AM

The broken link should now be fixed. Thanks.

As regards quaternions, I don't see any reason this is particularly related.

Posted by: Michael Nielsen at June 6, 2004 11:13 AM

Oh, I was musing since I recall that the Pauli spin matrices can get recast as quaternions and thus the matrix operations get turned into vector operations (taking advantage of the fact that complex 2D vectors and matrix operators are equivalent to a version of Hamilton's quaternion work). I don't really know enough yet to compare though, I just remember reading about this at some point in volume I of Grainger's quantum mechanics series.

Posted by: agm at June 7, 2004 07:11 AM