[Science] Quasicrystals

I saw an awesome talk yesterday, part of the series organized by the Perimeter Institute. Paul Steinhardt is a famous physicist from Princeton. He described the history of the research on "quasicrystals", how it went from the status of an impossibility, then to the status of a theoretical possibility, to finally reach the status of a admitted fact, with at each step some people (physicists) claiming that the next step was impossible. I appreciate to its right value the remark from Paul when I chatted with him after the talk: "it just proves that you should not trust results unless they are formally proved". Allelouia! Finally a physicist saw the light!!! ;) [Edit 2006/09/18: Although by saying so, he once again claim a "proof" which isn't one, merely an example...]

His talk was very good, reaching scientists as well as children, with several sessions with a webcam pointed from above to a brightly lighted table, allowing him to do live demonstrations. I heard about it but that's the first I saw. I would like to have one in class, and it would certainly be a must for video conferences. Does not seem expensive, we should see them arrive soon at the university. He also exhibited a 3d construction obtained through a "3d printer", which you can see on the picture on the side, hold by another Paul. I heard about those 3d printers, but again that was the first time I saw for real an objected thus created. I guess we will wait long before we get those at the University though...

One thing excited me a lot. The quasicrystals are based on a relaxation of the definition of a crystal, which permit materials with similar or stronger properties than crystals. The main arguments against their real existence, as opposed to a theoretical object, was that to create them one would need non-local rules. This was ultimately solved by finding a set of local rules allowing to create quasicrystals. You can see an example of how those local rules are implemented in the real world on the pictures on the right: the notches identify the faces and forbid some alignments, forbidding local moves which could result in a contradiction in the global construction.

I had the same problem with the Bak Sneppen model, a model of evolution on which I worked for quite a while: we have a model with nice properties, which could explain many things in Nature, but it uses non local rules, so that detractors claim that this model can't be true. I asked Paul Steinhardt if he knew some mathematical analysis of quasicrystals, so that I could try to apply their analysis in space time rather than in the 3 geometric dimension, but he claims that mathematicians refuse to work on those. He made me wanting to look more at this problem, I will do some more bibliography! [Edit 2006/09/18: Of course, there is a large bibliography in Mathematics about such processes, and that actually I knew some of it...] The video of the talk should soon be uploaded on the mediasite of the Perimeter Institute, and you can read the abstract of the talk.

[Art] Drawing

woman at the window
Originally uploaded by LeJyBy.

I felt tired today after the basket ball game and the lunch with Hans, I did not do much, so I played some music (my poor neighbours!), played with the Tablet PC and did some drawings. I did not manage to configure The Gimp properly, so I drew under Journal. It is truly magic for a beginner like me to be able to duplicate and experiment on several copies of the same drawing, or even simply to be able to erase perfectly (on paper there is always some remain of my previous drawing).

I did a Dragon, I did some Thingker sketches (the character of my never-truly-started comic), but somehow the thing I seem to be doing the best seems to be naked ladies: maybe I should find myself a girl-friend rather than stay all afternoon at home...

[Academic] Piggy-Backing

I learned a new meaning of the expression "Piggy Backing" (maybe someone should add it to wikipedia?). I was familiar with the expression in the wireless world, where it means using someone else's network, with or without the authorisation of the owner. H4ck3rs do it illegally, and researchers study protocols which would allow to do it and benefit all users: you might be willing to let people piggyback on your network if they allow you to piggyback on theirs, so that everybody gets a better coverage. It seems that in the world of academia, this expression refers to the action to put your name on a paper when you did not contribute to it, but merely attended meetings where the results were discussed. Of course it is nasty, but I don't think that it happens to often, nor that it matters too much: someone piggy-backing just won't get invited to the next meeting, and in most cases I have seen, people retract their name from the project if they feel that they did not contribute enough. I would not know how to name the opposite of piggy-backing (backstabbing maybe?), which would be to attend a meeting, participate to the discussion, but leave to publish your own paper without discussing it with the others. Of course depending of the rules of the meeting it could be accepted or not (it is not in the discussion group that I created), and anyway it is arbitrary and difficult to check (you won't read all the publications of all the members just to check how much the discussion group influenced them). But in most cases that I can think of, i.e. in a meeting between people of the same group, the same department, or the same scientific community, I think that the moral assumption is that people share their ideas not for anybody to take home selfishly, but for others to share back their own. It does not necessarily means that all the participants will be authors of the same paper, but that all of them could potentially be authors, if they agree to work more on the writing. I think that this second kind of "exploitation" happens more often, I dislike it a lot, but I am not sure how accepted or disliked it is in TCS. The divergence of opinions about it comes in part from a disagreement over the relative importance of technical results vs new ideas: on one hand there is the view that only the solution of a problem deserves credit and respect, and on the other hand I highly value identifying the problem, coming up with a proper definition for it, along with all the steps of the discussion which leads to the final solution (closing and eliminating dead-ends and clearing the path), including errors. Typically in a discussion group there is more negative results than positive ones, but those are required as well as the positive ones to reach the final result...

[Fun] Me, the butterfly...

Face in the sun
Originally uploaded by LeJyBy.

I remember a stupid time-travel story where hunters go to the time of dinosaurs, make a mistake, and come back to their time to find a much more cynical humanity. They then realize that they killed a beautiful butterfly in the past, the ancestor of those which would inspire humanity with poetry and art.

I feel like a butterfly when I am teaching, whether it is juggling, unicycling, music, or algorithms and mathematics; or even when I am passing people with my accordion or my unicycle and I make them smile. I could die any time, without children or "grand oeuvre" associated to my name, I would still be happy to have inspired many people with some of the essence of poetry, gameplay, joy of life.

On Saturday I organized a pizza party with a lot of playing with children and adults alike, teaching them how to make pizza, how to sculpt balloons and create levitating objects with magnets. On Sunday I went to the Waterloo Art Festival and met Jean, a beautiful young girl eager to learn unicycling: you can see her smile, she progressed very quickly!

[Culture] China Rises

Sophie
Originally uploaded by LeJyBy.

I just watched a DVD "CHINA RISES", produced by the "Canadian Broadcasting Corporation". Among the things that impressed me the most, beside the horrible conditions of some of the workers, which (at least European) news media like to point out, is on one hand the huge amount of pollution released, and on the other hand how much arable lands have been devastated. Some other facts are worth of notice: still more than half of the products exported from China are produced by state-owned companies: it seems to me that the opening of China to private entrepreneurship can be seen as a clever combination of incentive to innovation with still a good part of good planning. How much planning was left, and how much improvisation, was heavily questioned at some point of the DVD, expressing in particular worries about the capacity of China to produce food to sustain its own population. The part which pleased me the most was the interview of Zhang Yue, a Chinese millionaire who got rich selling air-conditioners which consume less electricity and pollute less. He was very eloquent talking about the pollution in China, and the English part of the website of his company, Broad Air Conditioning, beside its various typos, is as eloquent as the owner. The guy seems to be also funding his own farms to provide food for his employee and himself: the kind of initiative that western companies are so cynical about. Second of my list of favorites passages, among the extra videos on the second DVD, "A panorama of present day China": from the beautiful country-side to the illuminated new cities, accompanied by a variety of very nice music, ir reminded me of the music of Philip Glass, who composed the music of the Qatsi trilogy. The future new chair of my department seems to have an odd fascination for the future of China, I wish he could see this DVD! I am also reading "Collapse" from Jared Diamond (who wrote the master piece "Guns, Germs and Steel" that I read earlier): there is a chapter on China, I am curious to see what he has to say....