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Dec 10, 2010 Winning the Nobel prize aged just 39 could easily have gone to the head of Eric Cornell, the physicist who shared the 2001 prize for creating the world's first Bose–Einstein condensate (BEC). But when Physics World reporter, James Dacey, caught up with Cornell he encountered a firmly grounded experimentalist who can immediately spot the danger of complacency. In a wide-ranging discussion Cornell describes the speed at which his discovery was accepted by the community, his latest research project, and his unease with the responsibility that accompanies his Nobel medal.Cornell won the 2001 Nobel Prize for Physics "for the achievement of Bose–Einstein condensation in dilute gases of alkali atoms, and for early fundamental studies of the properties of the condensates". He shared the prize with his University of Colorado colleague Carl Wieman and Wolfgang Ketterle of the Massachusetts Institute of Technology. BECs are formed when identical bosons – particles with integer spin – are cooled until all particles fall into the same quantum state and behave as a single quantum particle. In June 1995 Cornell and Wieman succeeded in creating this extreme state of matter for the first time by using the newly developed techniques of laser cooling to take a cloud of rubidium atoms to near absolute zero. Ketterle repeated this feat a few months later with sodium atoms.
By the standards of physics experiments, it was not at all long and drawn out. The day we saw it, we also believed in it. It really seemed that it was a very clear signature. It was a more dramatic moment than these things usually are – over the course of a morning we came to believe it was there.
The day we saw it, we also believed in it.
Interestingly, when we first saw it, it was just a couple of weeks before a meeting in atomic physics that was happening on the island of Capri near Naples, so we had just a couple of weeks to convince ourselves that this was real enough to go public.
A week after that, there was a specialized talk on the topic of BECs near Strasbourg, and basically anyone who was interested in the BECs was there. It was a really rigorous meeting and there were a lot of probing and sceptical questions, but by the end I think we had pretty much everyone convinced.
I'll say that the thought had crossed my mind. But in those days, as now, typically a discovery is made and the Swedes wait maybe 20 years before they decide they are convinced enough...so I certainly wasn't expecting to get a telephone call early in the morning so soon.
Maybe the most active area of research is to use the condensate to explore model systems in quantum mechanics. Basically, they put the atoms in a lattice of interfering beams of laser light and you get this optical lattice. And you get a small number of atoms, maybe one of two atoms in each optical lattice site, and then using clever analogies you can say this system has the same underlying physics as the source of magnetism in an exotic material, for example.
What I've found I have to be careful about is that before the Nobel prize I was a young, slightly brash, not particularly cautious physicist. You know, someone would be describing an experiment and I'd say to my friends: "That's stupid! It's probably wrong." And now, if I say that, it's like: "Oh! Cornell says it's wrong. Scandal!" So I have to be a little bit more cautious in that respect because people take me more seriously and therefore I have to be more serious, which is a little too bad.
Yes, but I don't especially enjoy it. I mean, I like travelling, I like meeting people. But I don't like getting more involved in administration. I'm to become chair of my institute in a couple of months and I can't say that I'm looking forward to that. It seems to be something it's hard to get out of.
Apart from the BECs. I have another project going on, that I've been working on for six or seven years, which is getting at some of the same physics that they get at, at CERN, but using very different technology – looking for the asymmetry of the electron. As near as anyone can tell, the electron is a pretty symmetric particle, but we can't tell that for sure. So we're trying to do a much more careful study of whether the electron's north pole and the south pole are the same or whether they could be slightly different.
In nature, and in fundamental particles, there are some huge asymmetries and the biggest one is that if you just look around you the world is made up of electrons and protons and neutrons. It's not made up of antiprotons and antineutrons and positrons – it's a very imbalanced thing. If you look around the universe, there's a very, very tiny amount of antimatter.
We know that these basic violations of things like parity and charge conservation happen, and you can look around and mostly what you see are little tiny effects where you have to stare very hard at particles. Then you see immense, broad, crude effects, like we're all made out of matter and not antimatter. And connecting those two is not easy to do. The people who try to do that in a theoretical way are convinced that there are more small asymmetries at the microscopic scale than we have found so far. One of their favourite predictions is that the electrons should have this asymmetry...it's called the "electric dipole moment".
I think if I'd ended up being an accountant, then I'd be a hobbyist – the sort of person who builds remote-controlled airplanes.
I'm not a chalk guy; I'm an oscilloscope and laser guy. But you can have experimentalists who are working on very practical or impractical things. And likewise, you can have theorists who are working on very practical things. For instance, my electron experiment has involved developing technology to measure things very precisely. So even if the research itself isn't practical, maybe the equipment you develop might be.
Well, I've always been a bit of a tinkerer. I think if I'd ended up being an accountant for a living, then I'd be a hobbyist – the sort of person who builds remote-controlled airplanes or something like that. But I was always interested in languages. I was never very good at it... I had a picture that I'd do something more involved in literature or politics. I'm still very interested in politics, but really just as a spectator sport these days.
Carl Wieman and Steve Chu got out of the realm of the spectator sport and they put on their kit and their boots and they're actually playing. I've never done that and I don't really have an ambition to. But I do like to follow the game. My wife is much more involved in things like politics than I am, I wouldn't be surprised if she went for office one day, and I could be sort of like Denis Thatcher. I could do that job!
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