Recently, I completed a paper with Isaac Chuang and Aram Harrow. In the final stages of completing the paper we used a CVS (Concurrent Version System). For those not familiar with CVS, this is a piece of software which allows for version control (meaning it records the history of the source files) and nicely protects multiple authors working on the same source (basically this means multiple authors can work on the paper without fear of overwriting other’s changes.)
Using a CVS was definitely an improvement over the normal way paper collaboration works: the authors bounce emails back and forth with the source (aka LaTeX) attached. This essentially means that only one person at a time has “the token” and is responsible for working on the paper. While knowing that “you have the token” can press you into working efficiently to getting your changes done, not having anyone else working on the paper at the same time can be frustrating. Especially as a paper nears completion, and small changes are constantly being made by all authors, multitasking with CVS is definitely a plus.
But there are some issues with using a CVS which are more specific to scientific paper writing which make me think a paper collaboration CVS might be a really nice tool. Any ideas? Here is one idea:
Traditionally authors comment out sections which they change. Thus, for instance, if I am writing a new version of a paragraph, I will comment out the old version and keep it in the source. One reason for doing this is that it allows one to revert back fairly easily. With a CVS, of course, this is not strictly needed: the CVS is designed exactly to revert to prior version if necessary. But there is another reason why we comment out: we often cut and paste from the commented out component, or just want to quickly reread the commented out component as we write the new version. So the CVS needs some way of dealing with this technique: author’s want to have extremely easy access to previous versions. In fact what we really need is integration with an editor so I can turn on and off display of the “deleted” sections from prior version.
Schurly You're Joking Dr. Bacon
A new paper, a new paper! If you love the theory of the addition of angular momentum, and don’t we all just love the theory of the addition of angular momentum, then you will really love the new paper we (Isaac Chuang and Aram Harrow) just put on the arXiv. Unfortunately my spell check changed the title to Clench-Gordon and I didn’t notice. So I expect a lot of nasy emails complaining about the title. Doh. Well that’s what the replace button is for, I guess. Here is the paper:
quant-ph/0407082
Efficient Quantum Circuits for Schur and Clebsch-Gordon Transforms
Authors: Dave Bacon, Isaac Chuang, Aram Harrow
Comments: 4 pages, 3 figures
The Schur basis on n d-dimensional quantum systems is a generalization of the total angular momentum basis that is useful for exploiting symmetry under permutations or collective unitary rotations. We present efficient (size poly(n,d,log(1/epsilon)) for accuracy epsilon) quantum circuits for the Schur transform, which is the change of basis between the computational and the Schur bases. These circuits are based on efficient circuits for the Clebsch-Gordon transformation. We also present an efficient circuit for a limited version of the Schur transform in which one needs only to project onto different Schur subspaces. This second circuit is based on a generalization of phase estimation to any nonabelian finite group for which there exists a fast quantum Fourier transform.
Full-text: PostScript, PDF, or Other formats
Too Legit? Too Legit to Qubit?
Physical Review Letters has changed their sections around. Previously, quantum information was in the last section “Interdisciplinary Physics: Biological Physics, Quantum Information, etc.” For the more fundamental oriented papers, one would sometimes also submit to “General Physics.” Now quantum information has been moved to the new first section “General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.”
Is this a good thing? Since I am nothing if but a bag of poorly thought out opinions I will spew out some here. (1) It is nice to see that quantum information is consider a part of “General Physics.” “Interdisciplinary physics” seems a way to say, well there were these good physicists, and then they took interest in this other field which has overlap outside of physics, and since we liked these physicists we let them publish here. If I look at this move as acknowledging that quantum information has intrinsic value to physics, then I get goosebumps all over (sadly doubling the amount of stimulation I’ve had all day.) (2) The old “General Physics” section was notoriously harder to get papers accepted into if they had a quantum information tilt. Generally (err) this was because the papers submitted there were of a more foundational nature, and well, let’s not even go there. Will the movement of quantum information to general physics make it easier for foundational people to get published?