About a quarter century after their discovery, high-temperature superconductors still puzzle the scientific community, but each year scientists deploy new tools in order to understand the phenomenon. One new model uses geometry: Electrons moving in a curved space-time occupied by a charged black hole at the center can mimic strongly correlated systems such as high-temperature superconductors. Theoretical condensed matter physicist Philip Phillips and his colleagues at the University of Illinois, Urbana-Champaign , recently tweaked this model, with interesting results.
Phillips, whose Ph.D. is in theoretical chemistry, says he probably would not have taken such an unusual approach if his background had been more conventional. Science Careers talks to Phillips about how his circuitous route from chemistry to physics prepared him to go down this new research avenue.
The following highlights from the interview were edited for brevity and clarity.
At the university, I took a chemistry class, and that's when I really became interested in science. So I started taking many more science classes, and I realized too late that my real interest was in physics. I needed one more class for a physics major, and so I had degrees in math and chemistry.
I just started reading all the papers, and then I defined a new problem that others had not solved that I thought would advance the field. So the problem I was working on at Berkeley was an electron moving in a random array of scatterers. I learned the necessary math tricks to be able to solve this problem, and then I started doing it. That's what I'd learned from my adviser: how to chop something down that is completely new and make progress on it.
As a Miller fellow, I was doing this on my own. It was a big jump from single-particle stuff to, essentially, statistical mechanics, and the mindset was very different. It was painful and a lot of stuff I had to learn, but it was what I knew I wanted to do.
This Science Careers article is a tie-in to Science magazine’s feature  on superconductivity.
[In 1998, Argentinean physicist Juan] Maldacena made a conjecture in which he argued that there is a relationship between a strongly coupled quantum mechanical system and a gravitational system [that] is entirely classical Einsteinian gravity. So in fact, strongly coupled quantum mechanical systems that are charged are equivalent to a curved space-time with a black hole in it. We showed that if you just introduce some probe fermions and these probe fermions are coupled to the space-time in a particular way, that system looks identical to the normal [nonsuperconducting] state of high-temperature superconductors.
Others have used this mapping before. What we did that was new is that we used a particular interaction between the probe fermions and the black hole that is really irrelevant to the physics of the black hole but changes the physics at the boundary of the space-time [which is where the quantum mechanical theory lives]. No one suspected it.
With such a model, you can just forget about trying to figure out what the basic building blocks are, just go and solve this geometry problem and extrapolate it to what's going on at the surface of this geometry, and you'll see what the quantum mechanical system is doing.
I certainly thought that, God, if I were more traditionally trained, maybe I could have known some of the pitfalls of some of the things I've tried in the past. But now it's turning out that it was a good thing. The most important thing about my roundabout way is that I don't have any biases. I'm very open to new approaches and new problems and I don't mind just going and rolling up my sleeves and trying something new. This research is the culmination of what I thought I wanted to do when I was a graduate student.
1979: Receives bachelor's degree in math and chemistry from Walla Walla College in Washington state
1979–81: Graduate research assistant in theoretical chemistry at the University of Washington, Seattle
1981–84: Miller Postdoctoral Fellowship, University of California, Berkeley
1984–90: Assistant professor of chemistry, Massachusetts Institute of Technology, Cambridge
1990–93: Associate professor, Department of Chemistry, Massachusetts Institute of Technology, Cambridge
1993–99: Associate professor, Department of Physics, University of Illinois, Urbana-Champaign
2000–Present: Professor of physics, Department of Physics, University of Illinois, Urbana-Champaign
Elisabeth Pain is Contributing Editor for Europe.