Tax avoidance

I just had the pleasure of talking to an estate agent, who was trying to put me in touch with a company that lets one avoid stamp duty, using a scheme something like this one.  Frankly, I'd rather Mr Osborne had the money than a bunch of shysters *sigh*

Time management

In principle, when attending a conference, it would always be nice to prepare the talk carefully, long in advance, preferably before travelling.  I have been accused of having bad time management for not (always) doing so. With so many things I want to do, I find it optimises my time best to use the journey to prepare my talk, though it doesn't always work out as swimmingly as I plan.  It seems that things have never been much different.  I am sitting having lunch in Plovdiv, reading George Gamow's Thirty Years that Shook Physics, about the early history of Quantum Physics, and I came across the following anectode:

[I was] asked to deliver a lecture in the institute of Henri Poincaré, of which he [de Broglie] was a director. I decided to come well prepared. I planned to write the lecture down in my (still) poor French on board the liner crossing the Atlantic, have somebody in Paris correct the text, and use it as notes at the lecture. But, as everyone knows, all good resolutions collapse on an ocean voyage offering many distractions, and I had to face the audience in the Sorbonne completely unprepared.

If it's good enough for Gamow...

P.S. I am writing this sitting in a café in Plovdiv, next to the ruins of the Roman hippodrome. From my seat, I can't take such a great picture of it (since it's basically underground), so the picture attached to the post is of the square, with the Djumaya mosque to the right). The sundial on the corner of the mosque is about an hour out, but I guess it doesn't cope with summer time very well.

Rila Mountain Workshop & Chaos

Last week, I was in the Rila Mountains in Bulgaria for a nuclear physics workshop.  Like ever, I find myself newly-invigorated with the fun of doing research, talking about it, and finding out what other people are getting up to.  The picture in the post is the view from the conference room, on those rare occasions when my attention was not fixed on the speaker.

There were two talks about the link between quantum chaos and nuclear spectra.  Quantum chaos is nothing but the quantum analogue of classical chaos, in which, for example, two trajectories in a dynamical system with very similar starting points will diverge in behaviour in later times, no mater how similar the starting positions.  This makes the future behaviour of such systems hard to predict, as even though the equations are deterministic, the ability to measure the starting point with infinite accuracy is not possible.  This is one reason why weather forecasting is so hard.

In quantum mechanics, most systems are not quite like this.  We don't necessarily talk of trajectories, and starting positions may not necessarily be allowed to be close together thanks to quantisation.  In nuclear physics, the normal language of quantum chaos is in terms of the statistical spacing of energy levels and not much to do with trajectories.  In nuclei, this energy level spacing agrees with the predictions of random matrix theory, suggesting some chaos in the underlying nuclear force.  A few years ago I tried to do some work on the link between chaotic motion in nuclei using a kind of quantum theory which had a semiclassical aspect to it, which showed both classical chaos in its semiclassical trajectory and quantum chaos in its spectrum.  I thought I had at least hinted, in making this link, at something profound, but the referees didn't think so.  I ended up including it in a lightly-refereed conference proceeding, which has been lightly-cited since, but listening to the talks made me think I should pick up the subject again.

Since the conference has finished, I've been having a holiday in Plovdiv, Bulgaria's second city.  I'm going home tomorrow, but I'll be a bit sad to leave.  The weather is nice, it's a nice city and the beer is cheap.  But all good things must come to an end...

The Nature of Tin-100

Some large fraction of experimental work in nuclear physics concerns exploring the boundaries of what nuclei exist in nature and how they behave.  Nature allows nuclei - made of protons and neutrons - in certain combinations only.  Broadly speaking, the number of protons and neutrons should be similar, and not too large.  The conditions are set by the fact that protons like sticking to neutrons and vice versa, but not so much to each other, but as long as there are roughly equal amounts then it's okay, and that protons, being electrically positively charged, don't like to congregate together in large numbers.  This second effect means that when you start getting to the heavier elements (with >20 protons, say) then the proton to neutron ratio favours neutrons.

One of the most "exotic" nuclei with the same number of protons and neutrons yet observed in the laboratory is Tin-100, with 50 protons and 50 neutrons.  This is a particularly special case, since 50 is a so-called magic number in nuclei, which means that having 50 particles of one type is a particularly stable configuration.  The fact that it is heavy and does not have the excess of neutrons to balance the repulsive electric force means that it is nevertheless a bit on the unstable side.

Still, having these magic numbers makes it important to study, as the structure should be particularly clean and easy to understand from a theoretical point of view, which is why my colleagues have just published this article in Nature describing some of its properties.  Particularly they have looked at the beta-decay, which gives a measure of the structure of the nucleus as a proton decays into a neutron to turn it in to the neighbouring nucleus Indium-100. 

Good job Surrey colleagues, and I'm sure our REF coordinator will be pleased, too.

End of the year

It's that time of year when semester has just finished.  The undergraduate students have left, and we have had our first examination board meeting today, with the external coming along later in the week for a second meeting.  It's nice to see the results of the hard work of most of the students, and I'll look forward to the graduation ceremony next month, where I get to dress up in academic dress and see the students do the same as they are formally awarded their degrees.

So now I have three months ahead of me with little UG teaching-related activity.  Except that I'll be teaching a new course called "Advanced Computational Techniques" in October, so need to get that in to shape.  First stop, though, is conference in Bulgaria.  Hopefully my white linen suit from an online made-to-measure tailor will arrive in time...

C. S. Wu

Having noticed in my last post, somewhat after the fact, that it would have been the 90th birthday of Andrei Sakharov recently, I notice that my SEPNet colleague, Karen Masters, has just blogged about the 100th anniversary of the birth of another giant of nuclear physics, C S Wu.  Read her post here.

Sakharov Stories

When I was at secondary school, one of the biggest news stories was the ongoing changes happening in the Soviet bloc.  From perestroika and glasnost, then on to the demise of the Soviet Union and the rest of the communist countries in Eastern Europe.  It was through these stories that I learned the name of Andrei Sakharov for his role as a peace activist. I think I was vaguely aware at the time that he had a background in science, though I can't remember now if I knew he was a nuclear physicists.

Sakharov died while I was still at school, in 1989, in time to see most of the changes.  Now, in 2012, when 1989 is more than half my life ago, I am a nuclear physicist (though an inferior sort to Sakharov), and I note that the journal Physics-Uspekhi has published a series of articles commemorating Andrei Dmitrievich, on what would have been his 90th birthday, yesterday.  The all-round good guys and gals of the publishing arm of the Institute of Physics publish the english translation of Physics-Uspekhi, and being the generous sorts they are, they make all articles free to read for the first month after publication.  There are some nice biographical articles there, by old names from Russian physics, and they are worth a read.  There are some more technical ones, too, which are probably less suitable for a general audience...