 So I'm a condensed matter physicist, study various new types of materials that people discovered in the laboratory. And people found about 25 years ago so that there were these high-temperature superconductors that we really wanted to understand. They had a certain way of conducting electrical charge that didn't seem to fit into any of the paradigms of condensed matter physics. And this new state of matter we now understand is really a new type of way of many particles organizing themselves. They're all entangled with each other in a complicated way. That makes it very difficult to describe that by the standard tools of condensed matter physics. So in about, I guess it was 2007, I was looking for just some tools that one could use, or even a simple toy model, as we call it, where you could describe completely the properties of a complex entangled state of matter. And that's when I learned about, well, I knew I had heard about something called the ADS-CFT correspondence that came out of string theory. And this is a tool that allows you to relate, in some ways, very complex entangled states of matter to theories of gravity. And so that was really quite a powerful tool that allowed us to make some progress. But it was very useful and instructive progress, but it was only for a certain very special types of states of matter, which in addition to having complex entanglement, also have a high degree of symmetry. To really understand the experiments, you have to lower the symmetry quite a lot. And that's something we've been making, I think, some progress on since then. There have also been interesting cross-fertnization between condensed matter physics and mathematics. So there are these topological states of matter, which I've also worked on. And some of my co-prisoners, in fact, worked on even more, where there's a close connection between new developments in topology and mathematics and how you classify different types of entangled states of many particles. And I'm hoping also now, initially, there was certainly a one-way street from string theory of methods affecting condensed matter. But what's happened in the last five years or so, I would say, is that ideas from condensed matter are now influencing how string theorists also think about problems of quantum entanglement, near black holes, and so on. So it's gone both ways. And that's, of course, been very exciting. I mean, it's always great when you're in a given field, you have a certain mindset and a certain way of thinking. And it's very useful when somebody else says something that may seem very obvious to them, but to you then has very non-trivial implications. So if I take an ordinary metal like copper or silver or gold, it has many electrons that are delocalized throughout the entire metal. And that's why they can conduct electricity and heat. And that's why they're so reflective. Now, these electrons, as they're moving around, also repel each other. So they really feel by the Coulomb interaction. And really to do a full theory, you have to account for this repulsion between the particles. But it turns out, in some way, you can account for it very simply in most metals. You simply just assume that what happens is that each electron has a little cloud around it, what we call a screening cloud, which accounts for the local adjustments of the other electrons around it. And this composite object, which we call a quasi-particle, then moves as if it's just an independent free particle. So just by putting the cloud, you take into account all of the multi-particle effects. So that's a very basic tool that's been like step one in almost any paper in condensed metaphysics for 50 years. And it's been incredibly successful. So this is why there was a kind of a crisis when the strange metals were discovered, where these tools didn't seem to work at all. There were a lot of very bizarre things being seen in experiments. So in a strange metal, really, you can't make this decomposition. You really have to treat the Coulomb entanglement and the interaction between the electrons completely, even when you're describing phenomenal microscopic scales. And I don't think we still have a complete theory for it, because it's a very difficult problem. But in a variety of simpler cases, for example, when you have a high degree of symmetry, then you can use methods of string theory. There's another model that I'll talk about in my lecture today, which is called the SYK model, which I happen to be the S, which was something I proposed with my first graduate student, Jean-Louis Yeh in 1993. And that also allows us to talk about complex entanglement but in a different situation. The real world is somewhere in between. And so just by trying different tools, we're trying to approach real experiments. Over the years, I've developed a close relationship with several groups around the world, and I'm constantly in touch with them. If they observe some strange new effect in their lab, sometimes they call me, or I hear about it at a conference, and we have lots of fun discussions. So really, even things my students are working on these days are very much related to things I heard about from my experimentalist friends like a year ago or so. So there's a constant back and forth. Even on the strange metal problem, there was a beautiful new paper by Louis Tyfair from Sherbrooke in Canada. And so that gave us a somewhat different perspective on this old problem, the latest observations. And we've been working with our theories to see if we can understand what you're seeing. I wouldn't say I helped design. That requires a lot of skill that I don't have. I mean, the experimenters sometimes tell me what they observe, and then I throw out some ideas and say it wouldn't be cool if you could also look at something else. And usually they just ignore me. But occasionally, something sticks in their mind, maybe. And then they design the experiment. I knew almost nothing about black holes when I started first looking into the tools of string theory. But yeah, I mean, there was already a lot of progress in that direction by string theorists and something called the ADS-CFT correspondents where they had related entanglement in certain field theories to entanglement across a black hole horizon. And that was a model that turns out you can apply to even to other entangled states of matter, not just those that are related to string theory, and particularly S-Y-K model. I mean, another amazing thing that happens that was first discovered in string theory with the idea of an emergent direction of space. And that's really crucial, in fact, to understanding black holes. So black holes are the feature that their entropy is proportional to their surface area, not to their volume. This was one of Hawking's great discoveries. And then string theorists realized that you can understand this remarkable feature by starting with a theory that, in effect, lives in the surface of the black hole. But if the entanglement is complex enough, it ends up looking like a theory of gravity with one extra dimension. So this, I guess, more disain us than the person who is most commonly associated with this insight. But there were others also. And then, so that particular insight served as a model for it. Then we started studying the S-Y-K model. And I realized that there were a lot of similarities to what was happening in string theory. So that led to the idea that maybe even the S-Y-K model could have an emergent direction. And that's something more recently, especially the K in the S-Y-K. Kutayev has played a crucial role in understanding how that actually happens. So there's a lot of back and forth, a lot of guesswork, a lot of wrong guesses. But ultimately, with the benefit of interacting with many people and over many years, something emerges that hopefully is correct. Well, some of the problems I'm working on are still kind of open. Like I said earlier, we have what you would call toy models of strange metals, where you've got the string theory models or the S-Y-K models. They're still not really a fully satisfactory description of the experiments. I mean, what we'd like to do, ultimately, is to quantitatively predict lots of observables. So I see myself chipping away at that problem, making things more realistic for quite a while. It's not easy, but I think every few years, I think, it's hopeless, but suddenly some progress gets made. So let's hope that happens in the future, too. And what's, I think, kept me going and really excited about the field is there always is the experimental discoveries. There's no shortage of experimental discoveries in the high-temperature superconductors of the strange metals. Just last year, there's this very exciting discovery of a twisted graphene. I don't know if you've heard about that. Twisted bilayer graphene, which, to everybody's amazement, was a superconductor. And now it's also a strange metal. So there's a whole new area where strange metals have appeared. And that opens up a whole set of new problems. So I think all of that is enough food for thought for at least a decade, if not more. Yeah.