Month: March 2004

A mathematician whose work I have admired for years is Chandler Davis. I’ve only sampled a small selection of his ouvre, but it’s always interesting.

So I was extremely interested to find this page, describing how Davis went to jail for six months in 1960, for refusing, on principle, to testify before the House Unamerican Activities Committee.

(As a technical paranthetical aside, I was rather chuffed earlier this year when Chris Dawson and I found a way of using one of Davis’ best-known results in a paper. Specifically, we made use of the Davis-Kahan theorem to understand how quantum entanglement arises as the result of competition between local and interaction terms in many-body quantum systems. The Davis-Kahan theorem is a very nice theorem that gives detailed information about how the eigenspaces of an operator change under perturbation. )

Ike Chuang has just released a package enabling quantum circuits for quantum computers to be drawn easily (link.)

With standard tools, quantum circuits are a pain to draw. When writing our book on quantum information, I would sometimes email Ike a request for a circuit (usually a scanned hand-drawn image), and two minutes later a beautiful eps file would show up! I’ve never used the package Ike has created, but I’m pretty confident it will be extremely useful for that small group of people who regularly draw such circuits.

What’s the point of running an academic blog? I’ll come back to this at some point, but for now wanted to mention three of the betterposts I’ve seen on this: here, here and the entire comments thread here.

What do Omar Khayyam, Gore Vidal, Information Geometry, and Neural Coding have in common?

They all appear as the subject of entries in Cosma Shalizi’s Notebooks. Many of the notebooks are as informative and thought provoking as the total is eclectic. Highly recommended.

A nicely done Java demonstration. (Via Mark Fernee).