This week I’m at Stanford University, where I went to graduate school, attending a conference celebrating the illustrious careers of two great physicists, Renata Kallosh and Steve Shenker.
Kallosh is one of the world’s experts on black holes, supersymmetry, cosmic inflation (that period, still conjectural but gaining acceptance, during which the universe is suspected to have expanded at an unbelievable rapid rate), and “quantization” (i.e., on how to define quantum field theories and quantum gravity theories so that they actually make mathematical sense — which is not easy to do correctly). Much of her work concerns supersymmetry and its application to quantum gravity and to superstring theory. Her technical expertise and her inventiveness are legendary, as is her friendly enthusiasm. I’ve known her since I was a graduate student; she was one of a number of famous scientists from the former Soviet Union who came to the United States around 1988-1989. Aside from just interacting with her within Stanford’s small community of theoretical physics students, postdocs and faculty, I also attended two courses that she taught on advanced topics, one on supersymmetry and one on quantization.
Shenker is famous for a number of papers that significantly changed our understanding of quantum field theory, quantum gravity and string theory. His fame derives in part from his ability to extract deep insights about physics from just a few mathematical clues — often ones that only he recognizes as being clues in the first place. Shenker was a faculty member at Rutgers when I was a postdoctoral researcher there in the mid-90s. (He later moved to Stanford.) I cannot count the profound lessons that I learned during those years from him (and the other Rutgers faculty), both at our daily group lunch, and in the lounge where several of the faculty and other postdocs would regularly gather in the mornings. And I was even fortunate enough to write a paper (on black holes and their entropy) together with him and another then-postdoc, Dan Kabat. Aside from his down-to-earth no-nonsense style, and his strong support of young people and their ideas, one thing I remember well about Shenker is that it was perilous to say anything interesting to him while walking back from lunch on a bitterly cold day. He would stop and think… and the rest of us would freeze.
In the wider world of the public, and especially the blogosphere, Kallosh and Shenker would probably be labelled as “string theorists.” Such terminology would be somewhat crude, for it would fail to capture the range and depth of their careers. Appropriately, the talks at the conference so far have ranged widely, including general attempts to make some sense of quantum gravity, discussion of the information-loss problem of black holes (the so-called “firewall” problem), unexpected subtleties in how quantum field theory works (yes, we are still learning!), new ways of thinking about the physics of electrical conductors and insulators, and advances in our understanding of cosmic inflation. And there were even a couple of talks on string theory. (That said, the long shadow of string theory, and its direct and indirect influence on many other subfields, can be palpably felt at this conference. More on that subject another day.)
Since I’ve been so busy with Large Hadron Collider physics in recent years, and haven’t been following these subfields closely, it’s been a very educational conference for me. I’ll describe some of the talks later in the week.