UC Berkeley Berkeley Scientific Journal Title Interview with Joel Fajans Permalink https://escholarship.org/uc/item/4w0693f3 Journal Berkeley Scientific Journal, 15(2) ISSN 1097-0967 Authors Gururangan, Kapil Owen, Elaine Ding, David Publication Date 2011 DOI 10.5070/BS3152011587 Undergraduate eScholarship.org Powered by the California Digital Library University of California interView with Joel faJanS Kapil Gururangan, Elaine Owen, David Ding Dr. Joel Fajans’ research has recently captured headlines Fajans: Sure. Our goal is eventually to study the as a part of the ALPHA collaboration at the CERN, properties of antihydrogen atoms. Antihydrogen is a Swizerland that created and captured antihydrogen form of antimatter made from an antiproton, which particles in November 2010. That event was named is a negatively charged proton and a positron which the #1 Physics Breakthrough of the Year by Physics is an antimatter electron, a positive electron. There’s World magazine and since then, the team has worked a substantial theory, called CPT [change, time and to store these anti-atoms for longer periods of time, parity symmetry] and variance which predicts that clocking 1,000 seconds in April 2011. After getting his aside from these changes in the sign, that hydrogen Ph.D. from Massachusetts Institute of Technology in and antihydrogen are absolutely identical and we’d 1985, Professor Fajans joined the physics department like to see if that’s really true. If it turns out not to be as a faculty member in 1988. His lab has since worked true, then the theory of physics, well CPT, would be BSJ on charged plasmas and the occasional paper on overthrown. gyroscopic motion that speaks to his love of biking. While in Switzerland, Professor Fajans shared his thoughts on the uses of antihydrogen and the future of “...what we thought we had antimatter research when Berkeley Scientific Journal spoke with him over Skype in the summer of 2011. caught, back in 2009, were indeed antihydrogen atoms, but at the time we just couldn’t prove it.” BSJ: What are the consequences of violating CPT? What would happen if you guys found out there was some difference between antihydrogen and regular hydrogen, apart from the charge of those particles? Fajans: Well, there could be many consequences but the most, the ones were likely to look for first is to look at the color with which antihydrogen glows. You may know that all atoms glow with characteristic colors. You see that in neon signs. Some of the time they’re blue. Some are red. It has to do with the gas that’s inside the signs – this color is characteristic of the atom, and it turns out that it’s something that scientists can measure with extraordinary precision. In principal, we can measure the color of something, BSJ: Because were doing this for our science fiction more specifically the wavelength, but we’ll just call issue, we were really interested in your anti matter it the color to one part in 1 to the 18th. That is the research you are doing at CERN. Can you tell us the precision of 1 followed by 18 zeros. Now, that in and goal of your project for what you are doing at CERN of itself may not seem that exciting, but one of the Switzerland is right now? motivating reasons for doing this is because it might help answer on of the grand challenges in physics and Berkeley Scientific Journal • Science fiction • SPRING 2011 • Volume 15 • ISSUE 2 • 1 in sciences. Mainly, why a more advanced form of further studied the properties of antimatter. I guess it’s hard to say. Right now our goals this year are two- isn’t there more antimatter Schrödinger equations to some extent, its come back to Berkeley since I’m a fold. One, we are trying to start to do physics with in the universe? The theory seemed to him to be quite member of the team, there are many members on the these atoms – start to do the spectroscopy with these of the big bang, which is useful and predictive and team, about 40 people from institutions worldwide. atoms. Second, our other goal is to simply get more of a remarkably successful turned out to be correct We became the first people to trap neutral antimatter. them and make them more easily. It’s still a struggle theory, has a small problem equations. They have a People have managed to trap an antiproton and for us to trap – not to make them, it turns out to be with antimatter because it problem in which it is positrons before. The goal is to keep the trapped in fairly easy to make antihydrogen atoms – but it’s still predicts that there should possible, in fact necessary one place. This isn’t so easy to do because matter and a struggle for us to trap the antihydrogen atoms that have been just as much that his equations would we’ve managed to make. antimatter in the universe blow out, that would be as matter and when you mathematical infinities BSJ: How much anti hydrogen look around us that appears in the problem and he “...if you had a fistful of antimatter you could can you make? Say in a couple not to be so. It appears believed in this theory make a rocket probe that would go to the stars...” days or something. that there’s mostly matter, and he believed in his almost entirely matter for equations, so he invented Fajans: Well in the terms of that in the universe and a way to get rid of those atoms we can make quite a very, very little antimatter mathematical infinities antimatter, when they touch each other, they explode few at the moment. We make about 5,000 antihydrogen and nobody knows why. which was basically to – they blow up. Physicists call this annihilation. In atoms. Of course we start with ingredients, positrons This actually has a name – pretend that there were fact, when antimatter touches matter, all of the mass and antiprotons, about every 15 minutes when we BSJ it’s called the baryogenesis positive electrons in the in the matter and the antimatter gets converted into have beam. I will come to that in a second. We can problem – and its one of world and amazingly energy, via Einstein’s famous equation E = mc2, which make about 5,000 anti hydrogen atoms. But even on the outstanding critical enough this purely predicts the amount of energy that you get out of all of our best days, we only manage to keep one of those BSJ problems in physics is to try hypothetical prediction this mass. If you want to keep antimatter around, you atoms around, so we lose 4,999 and we keep one of and explain that. Well, even was quickly found to have to make a bottle with no sides. You can’t simply them entrapped. Our experiment runs 24 hours a though the connections are be correct by a physicist put it into, say a glass bottle, because as soon as the day, but there are other experiments with which we sort of subtle, if it turned named Carl Anderson, antimatter hit the sides they will annihilate and that share the antiprotons for, and so we run effectively out that antihydrogen was who detected positrons would be the end of it. So you have to make a bottle 8 hours of protons a day and with that we can, at 4 different from hydrogen, in the early 1930’s. that has no sides and the way physicists do this is to times an hour, make 20,000 atoms an hour if things are and glowed a different That’s where it stood use magnetic and electric fields. But it turned out to running well. And we’ve got 8 hours, so that is 160,000 color; this might explain for a while, but then be particularly tricky for antihydrogen atoms. What antihydrogen atoms an hour or something like that. this rather fundamental people started to wonder we succeeded in doing last year was to finally manage 160,000 antihydrogen atoms a day, but we will only mystery of how it came to whether or not there were to build a bottle that would contain some be here. antiprotons, protons that antihydrogen atoms. were negatively charged. BSJ: In terms of the actual At the time the biggest BSJ: Yes, so we read the paper that you guys “160,000 antihydrogen atoms a day, history of this field, I accelerator in the world wrote regarding you trapped it for, I believe, understand that Berkeley is was in Berkeley partially 1,000 seconds? but we will only trap a few of them.” featured quite heavily in the to answer this question. development of anti matter The building in which Fajans: Right. and I think there have been it was built was just a couple noble laureates recently torn down. Up BSJ: And that’s enough time to perform the associated with it. Can you until last year you could spectroscopy and other experiments? trap a few of them. walk us through how this go up into the Berkeley BSJ: So you mentioned beam? field has been developed lab and you could see Fajans: Yeah, 1,000 seconds in physics terms is forever. over time and sort of how the building and the It’s sort of boring actually. We had a joke that we could Fajans: Yes, these experiments have to be done at we’ve lead up to this sort Figure 1.