Month: December 2005

This is the first year in a few that I haven’t been applying for jobs (You might suspect that this makes me less grumpy. Well, judge for yourself!) Now I could be wrong, but is this the first explicit advertisement by a U.S. university physics department for a theory position in quantum information science?

Quantum Information Theory
The Department of Physics and Astronomy at the University of Southern California invites applications for tenure or tenure track positions at all faculty levels in the area of Quantum Information Theory.

Well even if it isn’t the first, can we take this as a good sign?

Interesting papers in experimental ion trap quantum computation:
Creation of a six-atom ‘Schrödinger cat’ state from Wineland’s group at NIST Boulder, Nature 438, 639-642 (1 December 2005.) Schrodinger’s cat is now six qubits big! And growing! What a cute little kitten.
Scalable multiparticle entanglement of trapped ions from Blatt’s group in Innsbruck. Nature 438, 643-646 (1 December 2005.) In this paper the group discusses experiment they performed which created the so-called “W” entangled state for up to eight qubits. That’s a quantum byte, peoples! Amazingly the group performs full state tomography on these states. Wow that sounds like an awful lot of graduate student hours.

The full t’ ‘t Hooft (look I put the apostrophy in the correct location!) article is now posted at Physics World (not Physics Today, as I listed incorrectly in my first post) commentary by Edward Witten, Fay Dowker, and Paul Davies. Quick summary: Witten thinks that quantum cosmology is perplexing, Dowker worries about the emergence of classical physics, and Davies postulates that complexity is the key to understanding the emergence of classicality. Davies suggests that quantum mechanics will break down when the Hilbert space is of size 10^120 and suggests that quantum comptuers will fail at this size. His argument could equally be applied to probablistic classical computers, and so I suggest that if he is right, then classical computers using randomness cannot be any larger than 400 bits.