The Economist: 90% of theoretical physicists work in String Theory?

29 September, 2006

An article in the weeks Economist on Loop quantum gravity contains this interesting statistic.

String theory is the more established of the two; some 90% of theoretical physicists are engaged in developing it.

I’m wondering where they get this statistic from. Having spent some time in a Theoretical Physics department, albeit not one of worlds top ones but far from the worst either, this stat comes as a surprise. I would have thought the majority of theoretical physicists didn’t work on either theory.

Most in my experience are more involved in exploring the outcomes of existing fundamental theory rather than trying to work out new ones. Those trying to solve various other unexplained phenomena like high temperature superconductivity for example.

Perhaps they are using a definition of theoretical physics that fundamental theories? Even so I would be amazed given the number of people working on fundamental Quantum Theory and Particle Physics etc. So did they make it up or does it arise from some very narrow definition of theoretical physicist?

Update: Due to my own sloppy style the title originally read “physicist” rather than “theoretical physicists”.

Shindig at the Clock

29 September, 2006

Finally last night I met some of the ozplogistans lead leading (what a cretan!) lights. He was there as was her and him. She was there and him, him, him,him, him and him plus others including commenters as well whom I must give apologises to for forgetting.

It was a good night although I ducked out at what I imagine was a relatively early time of just after 11pm. I’ve no doubt there are a few sore heads this morning. Its interesting though putting faces and speech to the words.

Not much more to say. I’m fairly sure photo’s will appear at some time. The only think I will mention is that Shaun Cronin has seen the Star Wars holiday special. I thought I was pretty geeky for actually knowing about it but he’s gone one step further. I’ve just had a quick look on YouTube for it and sure enough you can see various bits of it here including Princess Leia singing and Chewbaccas family growling at each other.

Efficient Markets and the Law

26 September, 2006

I’ve been catching up on some reading and I found this article in The Economist which is a few weeks old. In general I seem to criticise those who rubbish the Efficient Markets Hypothesis too much, but then there is the US Supreme court who it seems may take it too seriously.

JAMIE OLIS knows better than most people that the ideas conjured up by economists in their ivory towers can have a big effect on the real world. The tax accountant, found guilty of committing fraud while working for Dynegy, an energy-trading firm, has been doing time since March 2004, in large part thanks to a controversial economic theory, the efficient markets hypothesis.

Not just a little bit of time mind you, but 24 years, at least until a court threw out the sentence.

…In 1988, in Basic Inc v Levinson, the court endorsed a theory known as “fraud on the market”, which relies on the efficient markets hypothesis. Because market prices reflect all available information, argued the [Supreme] court, misleading statements by a company will affect its share price. Investors rely on the integrity of the price as a guide to fundamental value. Thus, misleading statements defraud purchasers of the firm’s shares even if they do not rely directly on those statements, or are not even aware of them.

Which is fine except for the fact that we know that prices move around regardless of new information, at least not the sort of information that comes from public announcements. Similarly news may take some time to be absorbed by the market which may over-react, and it is well known that volatility clusters. Don’t announce a fraud when the market is already volatile, the moves are likely to be bigger. Its a very tough call to equate a market move after an announcement entirely to that announcement, or even know when do you consider the information fully incorporated.

Of course that hasn’t stopped the lawyers and Judges from using it.
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Misbehavior of Markets: Mandelbrot

26 September, 2006

In 1963 Mandelbrot published research into the distribution of cotton prices based on a very long time series which found that, contrary to the general assumption that these price movements were normally distributed, they instead followed a pareto-levy distribution. While on the surface these two distributions don’t appear to be terribly different, (many small movements, and a few large ones), the implications are significantly different, most notably the pareto-levy distribution has an infinite variance.

This implies that rather than extreme market moves being so unlikely that they make little contribution to the overall evolution, they instead come to have a very significant contribution. In a normally distributed market, crashes and booms are vanishingly rare, in a pareto-levy one crashes occur and are a significant component of the final outcome.
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Port Arthur

26 September, 2006

While down in Tassie I visited Port Arthur for the first time. It was a clear sunny day, and it is a really beautiful place. The water, buildings and parks make it difficult to reconcile with the various miseries inflicted there.

I was a little surprised on the tour that its original conception were based on the Panopticon of Jeremy Bentham, essentially “a machine for grinding rogues honest”. It featured separation of different classes of prisoners based on their offenses which was novel at the time, and indeed the first boys prison in the British Empire. As a child at school of course I had learnt of the cruelty and of the dog line at Eaglehawk Neck, but not that it was in many regards an attempt at enlightened reform for its time.

Then of course there is the massacre, to walk through the hollow shell of what was the Broad Arrow Cafe its kind of hard to imagine over twenty people being shot there in a matter of seconds. The space seems so small and difficult to conceive how anyone could indiscriminately slaughter at so close a range. For me I can conceive how someone might do such a thing, long range, where the act is more abstract, but the relative confines of the Cafe were a surprise to me. I had imagined it as much larger.

Port Arthur is a worthwhile place to visit, beautiful with an oppressive overhanging history.


25 September, 2006

I’m back, fully charged up on Boags draught, mutton bird and instant coffee. I hope to continue with the Boags draught and go back to a better form of coffee. The mutton bird will remain a treat when visiting Tassie.

A little bit of sightseeing was had and I spent a bit more time in Hobart which is pretty little city. The boy enjoyed getting his feet wet up at Boat Harbour in the North west in the icy waters of Bass Strait.

I’ll get back to more usual topics soon.

Leave of absence

8 September, 2006

I’m off to Tassie for a couple of weeks to visit the in-laws and show off my son. So I won’t be boring entertaining you for that time.

See you all later.