Why I like condensed-matter physics

In 2001, I edited my first feature article for Physics Today about condensed-matter physics, “The Intriguing Superconductivity of Strontium Ruthenate ,” by Yoshiteru Maeno, Maurice Rice, and Manfred Sigrist. My previous engagement with condensed matter took place in 1982. Then, as an undergraduate at Imperial College in London, I took my first and only course on what the lecturer John Pendry and others referred to as solid-state physics.

I enjoyed that introduction to the field, but not enough to become a practitioner. A year later, I’d decided to pursue astrophysics. And in the 19 years that intervened between the course and the strontium ruthenate article, I barely thought about Brillouin zones, Fermi surfaces, or Landau levels.

Now, my attitude toward condensed-matter physics is not indifference, but enthusiastic appreciation. Yoshi, Maurice, and Manfred’s article helped effect the transformation, but what crystallized it was the Search and Discovery story I wrote about the discovery in January 2001 of superconductivity at 39 K in magnesium diboride .

All the superconductivity experts I interviewed for the story were thrilled. As an ignorant outsider, I couldn’t quite share their excitement, but as a journalist, I could see the elements of a good story: Jun Akimitsu’s patient and methodical search for new superconductors, the rush to explain the higher-than-expected critical temperature, the mystery of why magnesium diboride’s superconductivity had been overlooked.

Since that story, I’ve written about the spin Hall effect (classical and quantum), UV LEDs, quantized conductance in mesoscopic devices, iron-based superconductors, and other condensed-matter topics. What continues to delight me about the field is the mix of material science, experimental skill, imaginative theory, and practical application. Some topics have just two of those ingredients, but others, including topological insulators, have—or could end up having—all four.

My Road-to-Damascus conversion is, I like to think, not just of personal interest—which is why I’m writing about it here. At a recent meeting about industry–academic partnerships , the head of Stanford University’s physics department, Pat Burchat, remarked that of the 500 applicants to Stanford’s graduate physics program, one quarter wanted to work on theoretical particle physics, despite the dearth of eventual jobs in that field. Employment prospects aside, those 125 would-be particle theorists could encounter some of the same mathematical structures in a topological insulator or fractional quantum Hall system. And they’d have a good chance that any theories they devised could be vindicated in a lab, in their lifetimes.

Better, more inspiring teaching would make physics majors more aware of the rich and diverse challenges of pursuing a PhD in condensed-matter physics. I’m less certain of how to fire up the general, tax-paying public about Hall effects, tunneling magnetoresistance, and so on. As Rice University’s Doug Natelson observed on his blog , the obstacles are large.

Still, it shouldn’t be impossible. Although my job at Physics Today compelled me to become reacquainted with condensed matter, all it took to hook me was listening to the field’s experts explain what they do.