 For me, actually, there is a change of heart. And when I learned hand-in-hand physics in my PhD study, certainly, I learned the way of thinking in hand-in-hand physics. And about in my post-op period, I started to work with Bob Schriefer on connective physics. At the beginning, I feel very uncomfortable, although I like the field like a direction. But the way of thinking is different. But after a while, after some struggle, I start to get used to or learn this new way of thinking. And so it's quite a contrast. But after I learned this new way of thinking, then I also became an advantage for myself because I also know the energy way of thinking and the connective matter way of thinking. And there's two different ways of thinking and then combining together became very powerful. But since my thinking recently, I mostly start with lattice. So I say, maybe nowadays I should think myself as connective physics because most of my work now is lattice oriented. So all have this high energy component. So there's another cross-field study, which is the connective matter, this new topological matter. And the quantum information are really, really connected. So actually, we enjoy a lot of this connection. Some of my students actually have a background of quantum information, so make a very good contribution in this new field. And actually, there is yet another cross-field connection. The many-body entanglement is really a new phenomena. It's a phenomena we never seen before. So when you have some new phenomena, naturally, you need a new language and you need a new mathematics. So in some sense, it's similar to Newton's mechanical theory because when Newton introduced his mechanical theory, the calculus is not developed. So to derive the curve of the motion without calculus is very difficult. So he couldn't write down any mathematical formula. So actually, Newton had to invent calculus to write down his theory. So Tableau-Georda have a little bit similar. That is, this many-body entanglement is really a new phenomena. So actually, at the moment, one of our major research direction is to looking for and find the mathematical language, which are proper for Tableau-Georda or for many-body entanglement. We know that the Landau's symmetry breaking theory, the symmetry play an important role. So the group theory is the magnetic foundation for symmetry breaking theory. So what is the magnetic foundation for Tableau-Georda for many-body entanglement? So this will be a really interesting topic. So that's one of my research direction in recent years. I try to work with the mathematicians and I try to find the proper language to describe Tableau-Georda and the many-body entanglement. There is another low-end phenomenon also coming from Tableau-Georda. It's actually full-time. So the Maxwell equation can come out from Tableau-Georda. So we know Maxwell equation a long time ago. We know the light wave a long time ago. So it's kind of strange. This old phenomena can come out from Tableau-Georda. So what is the meaning for that? What is the significance of that? Actually, for the Maxwell equation, we have a very long story. When Maxwell first finds his equation and people wonder, light is a wave, but what is a wavy? So people at that time firmly believe that there must be some media whose distortion can propagate and this distortion satisfy Maxwell equation, that would be the media. And people are looking for this media for a long time. And even before we find it, we gave it a name called ether. So we say the distortion for ether gave us a wave satisfying the Maxwell equation. But for 150 years, we were looking for ether, but couldn't find it. And so I remember why I first learned Maxwell equation in my undergraduate study. You know, one naturally asks, what is a wavy? What is a wavy? And so I'm thinking about that. But the teacher told us, well, Maxwell equation and the electric magnetic wave is fundamental. Because it's fundamental, so we should not ask where it comes from. It's fundamental. So I think that's after so many years of failure. Finally, we can only have an answer. It's fundamental, so don't ask. And but however, this question is back on mind. It's kind of bugging me, but I have no answer. So I can live with it and continue my research. But then there's a study of this highly entangled system and this topology order and reveal that this highly entangled system actually can give rise to wave, which satisfies Maxwell equation. Actually, the picture is not that complicated. So we know that when I have a particle, when particles form a liquid, it will go to superfluid. And then we have a wave, it's a density of wave. So then what kind of media give rise to Maxwell equation? The answer is a surprising simple. We just need a string liquid. The liquid of a string of all kind of shape, all kind of size. So it's not like a small loop of string. The string can be as large as a system. It can wind around the system many times. So it's a string with all size and all shape. If you have this string liquid, then the wave in the string liquid would satisfy Maxwell equation. And it also answers very simple. The wave is simply a density of strings. And by the string have a direction. So when somewhere have a more strings, you should ask, more string in which direction? So the wave of a string is a vector field, have a direction and a strength. And that's exactly correspond to electric field in the Maxwell equation. And so actually, when you really do the calculation, just consider wave in the quantum string liquid, you just get a Maxwell equation. And furthermore, if you assume a string can branch, then as we call that a string net, we can get so-called Yang-Mills equation. Because the Maxwell equation is so-called for the U1 gauge field, Yang-Mills equation for the non-Abelian gauge field. So actually, when a string can branch, the string net wave would give rise to Yang-Mills equation. That's again, produce something we are familiar for the strong interaction and the weak interaction. So our old friends, the Maxwell equation, Yang-Mills equation, come out from this string net. Even more, actually, the end of a string is something topological extinction, which can produce Dirac equation, which is described electron. So the density of the string describe electron magnetic field and the strong interaction, weak interaction. The end of a string actually can describe electron or quark, even produce a firm statistics of electron quark and the Dirac equation. They're all old friends. So from this study of a highly entangled system, I started this topological order. For certain topological order, we get our old familiar friends. What that means? So I started dreaming. So maybe our vacuum is a system with topological order. It's a system with a strong entanglement. That's why the distortion and the disturbance of a vacuum produce those Yang-Mills equation, Maxwell equation, Dirac equation, et cetera. So maybe that's another application of a highly entangled system and topological order. Probably can explain some of these very interesting, rather maybe I should say exotic, but indeed a kind of a strange property. Why the interaction of our universe are always described by gauge field? Why we have Fermi statistics? Who ordered that? Fermi statistics is a very strange property. Why we have that? But however, with a highly entangled system with a string net, there is one way to understand those features from a single starting point, which is the so-called highly entangled qubit. If you view our vacuum as the ocean of qubits, which have some entanglement described by certain kind of topological order or string net, then this kind of qubit ocean with a proper entanglement can produce a Maxwell equation, Yang-Mills equation, and Dirac equation, and the quarks. But one thing we failed. We don't know how to produce Einstein equation. And seems that's the only thing we don't know how to do. So we wish there was some qubit ocean or some entanglement which can produce Einstein equation. Why that's significant? I don't know. Because at least, if that is possible, you may have found some magnetic material. These materials have a wave described by Einstein equation. That would be very cool. Actually, right now, one of our very active frontier in condensed matter experiments is to looking from quantum spin liquid. Who's the wave equation is the Maxwell equation and the Dirac equation? And actually, there's a few condensed material which may have that. But the sample quality still needs to be improved. So anyway, I like to really wait and see. So maybe in the near future, maybe in a few years, we probably can find this material which produce a Maxwell equation, Dirac equation. It's like a baby universe, like another universe in the lab. So when you're holding this sample, you can say, I'm holding a universe.