YouSaid · the spoken record

Cumrun Vafa

lines on the record: 172
first: 2021-07-26
most recent: 2021-07-26
sittings or episodes: 1
sources: podcast

Every line below is reproduced as it was said and linked to the record it came from. Nothing here is summarised or generated. Directory · Search · Corrections

“Thanks, Lexus. It was a pleasure, and I love talking with you. And this is a wonderful set of discussions. I really enjoyed my time with this discussion. Thank you.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Immortality I would get. Namely, at least I can hang on to this little piece of truth, even though I know, I know it's not complete. I know it's going to be imperfect. I know it's going to change and it's going to be improved. But having a little bit deeper insight than just the naive thing around us, little earthier and little galaxy and so on makes me feel a little bit more pleasure to live this life. So I think that's the way I view my role as a scientist.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“The process of being part of this thing that the reality, to me, part of what attracts me to science is to connect to that immortality kind of, namely the laws. Reality beyond us. Me, I'm resigned to the fact that not only me, everybody is going to die. So this gives a little bit of a consolation. None of us are going to be around. So therefore, okay, and none of the people before me are around. So therefore, yeah, okay, this is something everybody goes through. So taking that minuscule version of, okay, how tiny we are and how short time it is and so on, to connect to the deeper truth beyond us, the reality beyond us, is what sense of”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Helps you get your stuff together. I think that's true. But actually, I have a different perspective on that a little bit. Yeah. Namely, suppose I told you you're immortal. I think your life will be totally boring after that because you will not there's i think part of the reason we have enjoyment in life is the finiteness of it And so I think mortality might be a blessing and immortality may not. So I think that we value things because we have that finite life. We appreciate things. We want to do this. We want to do that. We have motivation. If I told you, you know, you have infinite life. Oh, I don't need to do this today. I have another billion or trillion or infinite life. So why do I do now? There is no motivation. A lot of the things that we do I don't regret it that we have more finite life. And I think that”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“I don't think about my mortality. I think that I don't think about my death and I don't think about death in general too much. First of all, it's something that I can't do much about. And I think it's something that it doesn't drive my everyday action. It is natural to expect that it's somewhat like the time reversal situation. So we believe that we have this approximate symmetry in nature, time reversal. Going forward, we die, going backwards, we get born. So, what was it to get born? It wasn't such a good or bad feeling. I have no feeling of it. So, you know, who knows what the death will feel like the moment of death or whatnot. So I don't know. It is not known. But in what form do we exist before or after? Again, it's something that it's partly philosophical, maybe.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“I'm lucky I'm doing that. I feel that if people follow their interest, they will find the niche that they're good at. And this coincidence of hopefully their interest and abilities are kind of align, at least some extent, to be able to drive them to something which is successful and not to be driven by things like this doesn't make a good career or this doesn't do that. And my parents expect that or what about this? I think ultimately you have to live with yourself and you only have one life and it's short, very short. I can tell you I'm getting there. So I know it's short. So you really... Not to do things that you don't want to do. So I think follow your interest is my strongest advice to young people.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“In my own case, I was planning to study economics and electrical engineering when I started MIT. And I discovered that I'm more passionate about math and physics. And at that time, I didn't feel math and physics would make a good career. And so I was kind of hesitant to go in that direction, but I did because I kind of felt that that's what I'm driven to do. So I don't regret it. I'm lucky in the sense that society supports people like me who are doing these abstract stuff. Which may or may not be experimentally verified even, let alone apply to the daily technology in our lifetimes.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“So, I have three sons, and in fact, to them, I have tried not to give too much advice. So, even though I've tried to kind of not give advice, maybe indirectly there has been some impact. My oldest one is doing biophysics, for example. The second one is doing machine learning, and the third one is doing theoretical computer science. So These facets of interest which are not too far from my area, but I have not tried to impact them in that way, and they have followed their own interests. And I think that's the advice I would give to any young person. Follow your own interest and let that take you wherever it takes you. And this I did.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“I call it physics. It may not be the physics I know today. For sure it's not, but I would be surprised if there's disconnected realities that you cannot imagine them as part of the same suit.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Biology and chemistry, and so on, gradually they came together. So it wasn't like together. So, yeah, I'd be perfectly understanding of a situation where we don't have the tools. So do the experiments that you think defines your consciousness in different form and gradually we'll build it and connect it. And yes, we might discover new principles of nature that we didn't know. I don't know, but I would say that if they are, they'll be deeply connected with the else. We have seen in physics, we don't have things in isolation. You cannot compartmentalize, you know, this is gravity, this is electricity, this is that. We have learned they all talk to each other. There's no way to make them, you know, in one corner and don't talk. So the same thing with anything, anything which is real. So consciousness is real. So therefore, we have to connect it to everything else. So to me, once you connect it, you cannot say it's not reality. And once it's reality is physics.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“I agree with you, and I think I'm fine with some topics being part of a different realm than physics today. Because we don't have the right tools. Just like biology was. I mean, before we had DNA and all that genetics and all that gradually began to take hold. I mean, when people were beginning with various experiments with...”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“There's no point you could say that this is conscious, there's no sharp transition, so it could very well be that what we call heuristically in daily life. Consciousness is similar, or life is similar to that. I don't know if it's like that or not. I'm just hypothesizing it's possible. Like, there”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“I like this example quite a bit. You know, we distinguish between liquid and a gas phase, like water is liquid or vapor is gas. We say they're different. You can distinguish them. Actually, that's not true. It's not true because we know from physics that you can change temperatures and pressure to go from liquid to the gas without making any phase transition. So there is no point that you can say this was a liquid and this was a gas. You can continuously change the parameters to go from one to the other. So at the end it's very different looking like, you know, I know that water is different from vapor, but there's no precise point this happens. I feel many of these things that we think, like consciousness clearly dead person is not conscious and the other one is. So there's a difference like water and vapor.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Definitely. I would say it will grow. I would not know if it grows because of consciousness being part of it or we have different view of consciousness. I do not know where the consciousness will fit. It's going to be hard for me to guess. I mean, I can make random guesses now, which probably most likely is wrong, but let me just do just for the sake of discussion. I could say, you know, brain could be their quantum computer, classical computer, their arguments against this being a quantum thing. So it's probably classical. And if it's classical, it could be like what we are doing in machine learning slightly more fancy and so on. Okay, people can go to this argument to no end and to know whether consciousness exists or not or life does it have any meaning or is there is there a phase transition where you can say does electron have a life or at what level does a particle become life maybe there's no definite definition of life in that same way that you know we cannot say electron if you”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“I'm perfectly fine in the intermediate situation to have rules of thumb or principles that chemists have found which are working, which are not founded on the basis of quantum mechanical laws, which does the job. Similarly as biologists do not found everything in terms of chemistry, but they think there's no reason why chemistry cannot. They don't think necessarily they're doing something amazingly not possible with chemistry. Coming back to your question, does consciousness, for example, bring this new ingredient? If indeed it needs a new ingredient, I would call that new ingredient part of physical law. We have to understand it. To me, that, so I wouldn't put a line to say, okay, from this point onwards, you cannot, it's disconnected. It's totally disconnected from string theory or whatever. We have to do something else.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“That's as far distance, far different scales of questions that we're asking here. The question is, is there a change of, is there a new law which takes over that cannot be connected to all their laws that we know or more fundamental laws that we know? Do you need new laws to describe it? I don't think that's necessarily the case in many of these phenomena like chemistry or so on you mentioned. So we do expect in principle chemistry can be described by quantum mechanics. We don't think there's going to be a magical thing. But chemistry is complicated. Yeah, indeed, there are rules of chemistry that chemists have put down which has not been explained yet using quantum mechanics. Do I believe that they will be at something described by quantum mechanics? Yes, I do. I don't think they are going to be sitting there in the shelf forever. But maybe it's too complicated and maybe we will wait for a very powerful quantum computers or whatnot to solve those problems. I don't know. But I don't think in that context we have no principles to be added to fix those.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Right. No, so let me describe what you just said. So there are two questions. One is whether or not the techniques are used in, let's say, quantum field theory and so on will describe how the society works.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Any form of reality, I call it physics. That's my definition. I mean, I may not know a lot of it. Like maybe the origin of life and so on, maybe a piece of that. But I would call that as part of physics. To me, reality is what we are after. I don't claim I know everything about reality. I don't claim string theory necessarily has the tools right now to describe all the reality either. But we are learning what it is. So I would say that I would not put a border to say, no, you know, from this point onwards, it's not my territory, it's somebody else's. But whether we need new ideas in string theory to describe other reality features, for sure, I believe. As I mentioned, I don't believe any of the laws we know today is final. So therefore, yes, we will need new ideas.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“So, first of all, we don't claim that string theory is the theory of everything in the sense that we know enough what this theory is. We don't know enough about string theory itself. We are learning it. So I wouldn't say, okay, give me whatever I will tell you how it works. No. However, I would say by definition, by definition, to me, physics is checking all reality.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Emphasizing the context of loop quantum gravity in some form. And so these ideas might be there in some kernel, in some corners of string theory. In fact, I wrote a paper about topological string theory and some connections would potentially loop quantum gravity, which could be part of that. So there are little facets of connections. I wouldn't say they're complete, but I would say most probably what will happen to some of these ideas, the good ones at least, they will be absorbed to string theory if they are correct.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“One foot on measures 1 over L, the other one measures L. And so, this duality reformulates. And when this space gets smaller, it says, Oh no, you better use the bigger perspective because the smaller one is harder to deal with. You do this one. So these examples of loop quantum gravity have none of these features. These features that I'm telling you about, we have learned from string theory, but they nevertheless have some of these ideas like topological gravity aspects”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“More precise string units. This inversion is a very subtle effect. And I would not have been or any physicists would not have been able to design a theory which has this property that when you make the space smaller, it is as if you're making it bigger. There is no experiment you can do to distinguish the size of the space. This is remarkable. For example, Einstein would have said, of course I can measure the size of the space. What do I do? Well, I take a flashlight, I send the light around, measure how long it takes for the light to go around this space and bring back and find the radius or circumference of the universe. What's the problem? Said, well, suppose you do that and you shrink it. He said, Well, they get smaller and smaller. So what? I said, Well, it turns out in string theory there are two different kinds of photons.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“String theory is more subtle than that. For example, I will just give you an example, and this is the kind of thing that we didn't put in by hand. We got it out. So it's more subtle than so, what happens if you squeeze the space to be smaller and smaller? Well, you think that after a certain distance, the notion of distance should break down when you go smaller than Planck's scale should break down. What happens in string theory? We do not know the full answer to that, but we know the following. Namely, if you take a space and bring it smaller and smaller, if the box gets smaller than the Planck scale by a factor of 10, it is equivalent by the duality transformation to a space which is ten times bigger. So there's a symmetry called Tidwati, which takes L to 1 over L. Well, L is measured in Planck units”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“We had not appreciated that fact, and we discovered by doing thought experiments in string theory that there's got to be an extra circle, and that circle is connected to an 11-dimensional perspective. And that's what later on got called M-theory. So there are these kind of things that we do not know what exactly string theory is. We're still relearning. So we do not have a final formulation of string theory. It very well could be that different facets of different ideas come together, like loop quantum gravity or whatnot. But I wouldn't put them on par, namely loop quantum gravity is a scatter of ideas about what happens to space when they get very tiny, for example, you replace things by discrete data and try to quantize it and so on. And it sounds like a natural idea to quantize space. You know, if you were naively trying to do quantum space, you might think about trying to take points and put them together in some discrete fashion, in some way that is reminiscent of Leopoldum gravity.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“But String was saying, sorry, we're 10 dimensional. So for a while, we thought that theory is wrong, because how could it be? Because string theory is definitely theory of everything. We later learned that one of the circles of string theory itself was tiny.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Yes, I think the latter. I would say that the containing ideas that are true, is my opinion, was what some of these ideas might be. For example, loop quantum gravity is to me not a complete theory of gravity in any sense, but they have some nuggets of truth in them. And typically what I expect happen, and I have seen examples of this within string theory, aspects which we didn't think are part of string theory come to be part of it. For example, I'll give you one example. String was believed to be 10 dimensional. And then there was this 11-dimensional supergravity. And nobody knew what the heck is that. Why are we getting 11 dimensional super gravity where a string is saying it should be 10 dimensional? 11 was the maximum dimension you can have super gravity.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“We have found arguments from within the swamp land kind of ideas why it has to be related. And so they're beginning to be these connections between consistency of quantum gravity and aspects of our universe gradually being sharpened, but we are still far from a precise quantitative prediction like we have to have such and such. But that's the hope that we are going in that direction.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Exactly. So that's the reinforcement of what we know in our universe. But we are finding that as a general principle. So we want to know what aspects of our universe is forced on us. Like the weak gravity conjecture and other aspects, how much of them do we understand? Can we have particles lighter than neutrinos? Or maybe that's not possible. You see that neutrino mass, it turns out to be related to dark energy. In a mysterious way. Naively, there is no relation between dark energy and the mass of a particle.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Show it's bigger than 10 to the minus 30 in the plank unit. So you find the mass of the electrons should be less than 1, but bigger than 10 to the minus 30. In our universe, the mass of the electrons 10 to the minus 20. Okay, now this kind of you could call postdiction, but I would say it follows from principles that we now understand from string theory. First principle. So we are making beginning to make these kinds of predictions, which are very much connected to aspects of particle physics that we didn't think are related to gravity. We thought, just take any electron mass you want. What's the problem? Has a problem with gravity.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“So that the gravity is weaker. So you connect this fact to the other fact. So we begin to find different facts that reinforce each other. So different parts of the physics reinforce each other. And once they all kind of come together, you believe that you're getting the principle correct. So weak gravity conjecture is one of the principles we believe in. As a necessity of these conditions. So these are the predictions string we are making. Is that enough? Well, it's qualitative. It's a semi-quantitative, just the mass of the electron should be less than some number. But that number is, if I call that number one, the mass of the electron turns out to be 10 to the minus 20, actually. So it's much less than 1. It's not one. But on the other hand, there's a similar reasoning for a big black hole in our universe. And if that evaporation should take place gives you another restriction and tells you the mass of the electron is bigger than is now in this case bigger than something.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“The reasoning for this turns out to be studying black holes. Ideas of black holes turn out to put certain restrictions of what a good quantum filter should be. It turns out using black hole, the fact that the black holes evaporate Fact that the black holes evaporate gives you a way to check the relation between the mass and the charge of elementary particle because what you can do, you can take a charged particle and throw it into a charged black hole and wait it to evaporate. And by looking at the properties of evaporation, you find that if it cannot evaporate particles whose mass is less than their charge, then it will never evaporate. You will be stuck. And so, the possibility of”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Gravitational attraction of the electrons will be bigger than the electric repulsion between two electrons. The gravity will be stronger. That's all. It happens that it's not the case in our universe because electron is very tiny in mass compared to that. Just like our universe, gravity is the weakest force we find in all these other ones which are part of the good ones Gravity is the weakest force. Is called the weak gravity conjecture. We conjecture that all the points in the landscape have this property. Universe being just an example of it, so there are these qualitative features that we are beginning to see. But how do we argue for this just by looking patterns, just by looking string theory has this? No, that's not enough. Need more reason, more better reasoning, and it turns out there is.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Universe. We don't know. And that is one of the challenges when string theory which point on the landscape, which corner of this landscape do we live in? We don't know. So what do we do? Well, there are principles that are beginning to emerge. So I will give you one example of it. You look at the patterns of what you're getting in terms of these good ones, the ones which are in the landscape compared to the ones which are not. Find certain patterns. I'll give you one pattern. You find in the older ones that you get from string theory, gravitational force is always there, but it's always, always the weakest force. However, you could easily imagine field theories for which gravity is not the weakest force. For example, take our universe if you take a mass of the electron, if you increase the mass of electron by a huge factor.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“The ones whose rank is less than 23. Anyone bigger than rank 23 belongs to the swamp land. They're influencing many of them. They're beautiful field theories, but not when you include gravity. So then this becomes a hopeful thing. So in other words, in our universe, we have gravity. Therefore, we are part of that dual subset. Now, is this jewel subset small or large? It turns out that subset is humongous, but we believe still finite. Set of possibilities is infinite, but the set of consistent ones, I mean, the set of quantum figures are infinite, but the consistent ones are finite, but humongous. In fact, that the humongous is the problem we are facing in string theory because we do not know which one of these possibilities the universe we live in. If we knew we could make more specific predictions about it.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“The swamp land is infinitely large. So let me give you one example. Take a theory in four dimensions with matter. Maximum amount of supersymmetry. Can you get? It turns out a theory in four dimensions with maximal amount of supersymmetry is characterized just with one thing, a group, what we call the gauge group. Once you pick a group, you have to find the theory. Okay, so does every group make sense? Yeah. As far as quantum field theory, every group makes sense. There are infinitely many groups, there are infinitely many quantum field theories. But it turns out there are only finite number of them, which are consistent with gravity, out of that same list. So you can take any group but only finite number of them, the ones who's what we call the rank of the group.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“So, string theory are those rare exceptions. So, therefore, the general principle that Feynman found was correct. Quantum field theory and gravity and quantum mechanics don't go together, except for joules, exceptional cases. They're exceptional cases. The total vastness of quantum field theories that are there, we call the set of quantum field theories, possible things. Which ones can be consistently coupled to gravity? Call that subspace the landscape. The rest of them we call the swamp land. It doesn't mean they are bad quantum field theories, they are perfectly fine. When you couple them to gravity, they don't make sense, unfortunately. And it turns out that the ratio of them, the number of theories which are consistent with gravity to the ones without, the ratio of the area of the landscape to the swamp land, in other words,”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Okay, very good question. So let's go back to what I was describing about Fine Man. Fine man was trying to do these diagrams for graviton and electrons and all that. He found that he's getting infinities he cannot resolve. Okay, the national conclusion is that field theories and gravity and quantum theory don't go together, and you cannot have it. In other words, field theories and gravity are inconsistent with quantum mechanics period. String theory came up with examples but didn't address the question more broadly that is it true that every field theory can be coupled to gravity in a quantum mechanical way? It turns out that Feyman was essentially right. Almost all particle physics theories, no matter what you add to it, Put gravity in it doesn't work. Only rare exceptions work.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“By now we are so confident about many such examples that has affected modern mathematics in ways like this, that we are much more confident about our understanding of what string theory is. These are another aspect, other aspects of why we feel string theory is correct. It's doing these kind of things.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Sign with the opposite sign was later confirmed by mathematicians. This is actually the opposite view. That is, physics is so sure about it that you're going against the mathematical wisdom, telling them they better look for it.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Only compute the absolute value of it. Now, this bothered us because how could you not compute? Unless the both signs were the same. So I conjectured maybe for every Colabia with the oil cactus positive, there's one with negative. I told this to my colleague, Yao, whose namesake is Calabia. That I'm making this conjecture. Is it possible that for every Calabia there's one with the opposite oil characterist Not reasonable. I said, why? He said, Well, we know more Calabias with negative oil. Said, but physics says we cannot distinguish them, at least I don't see how. So we conjectured that for every Calabia with one sign there's the other one, despite the mathematical evidence, despite the mathematical evidence, despite the expert telling us this is not the right idea. A few years later, this symmetry, mirror symmetry between the”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“So we were studying these compact variational string geometries. This is after my PhD now, by the time I've come to Harvard, we're studying these aspects of string compactification on these complicated manifolds, six-dimensional spaces called Cloud-BL manifolds. Very complicated. And I noticed with a couple other colleagues that there was a symmetry in physics suggested between different Calabias that suggested that you couldn't actually compute the Euler characteristic of a Calabia. Euler characteristic is counting the number of points minus the number of edges plus the number of faces minus. So you can count the alternating sequence of properties of the space, which is the topological property of a space. So Olekis of the Calabia was a property of the space. And so we noticed that from the physics formalism, if string moves in a Calabia, you cannot distinguish, we cannot compute the Euler characteristic.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“This is my necessary belief because I take the physical intuition perhaps literally in many ways that could teach us amounts. So now I've gained so much confidence in physical intuition that I make bold statements that sometimes takes math friends off guard. So an example of it is mirror symmetry.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“In fact, mathematics was helping it, like France. And so much more harmonious and gives insights to physics. So that's, I think, one of the main things I learned from interactions with Witten. And I think that now perhaps I have taken that to a far extreme. Maybe he wouldn't go this far as I have. Namely, I use physics to define new mathematics in a way which would be far less rigorous than a...”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“The different facets reinforce each other. You say, Oh, I cannot rigorously define what I mean by this, but this thing connects with this other physics I've seen and this other thing. And they together form an elegant story. And that replaced for me what I believed as a solidness, which I found in math, as a rigor, solid, I found that replaced the rigor and solidness in physics. So I found, okay, that's the way you can hang on to. It is not wishy-washy. It's not like somebody is just not being able to prove it, just making up a story. It was more than that. And it was no tension with mathematics.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Just feel like the electron, you're moving with this guy and do that, and so on, and you're thinking invariantly about physics or the way he thought about relativity. Like, you know, I was thinking of this momentum. He was thinking invariantly about physics, just like the way you think about invariant concepts in relativity, which don't depend on the frame of reference. He was thinking about the physics in invariant ways, the way that doesn't Gives you a bigger perspective. So this gradually helped me appreciate that interconnections between ideas and physics replaces mathematical rigor”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“There comes within as my advisor, and I see him in action. Thinking about math and physics. He was amazing in math. He knew all about the math. It was no problem with him. But he thought about physics in a way which did not find this tension between the two. It was much more harmonious for him. He would draw the Feynman diagrams, but he wouldn't view it as a formalism. He was viewed, oh yeah, the particle goes over there and this is what's going on. So wait, you're thinking really, is this particle? This is really electron going there. Yeah, yeah. Taking the perturbation. No, no.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“And no matter how hard I was trying, I was not being able to do that. And I was falling behind from my classes. I was not learning much physics and I was not making it rigorous. And to me, it was this dichotomy between math and physics. What am I doing? I like math, but this is not exact risk.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“On the other hand, to me, mathematics, even though it was rigorous, I think it sometimes didn't see the point of it. In other words, the math theorem by itself could be beautiful, but I really wanted more than that. I want to say, okay, what does it teach us about something else, something more than just math? So I wasn't that enamored with just math, but physics was a little bit bothersome. Nevertheless, I decided to go to physics and I decided to go to Princeton and I started working with Edward Whitten as my thesis advisor. And at that time, I was trying to put physics in rigorous mathematical terms. I took quantum field theory. I tried to make rigorous out of it and so on.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“He did actually. So I can explain because when I was a student, I had the biggest impact by him, clearly as a grad student at Princeton. So I think that was the time where I was a little bit confused about the relation between math and physics. I got a double major in mathematics and physics at MIT. And because I really enjoyed both and I write the elegance and the rigor of mathematics, and I liked the power of ideas and physics and its applicability to reality and what it teaches about the real world around us. But I saw this tension between rigorous thinking in mathematics and lack thereof in physics. And this troubled me. I was troubled by that. So I was at crossroads when I decided to go to graduate school in physics because I did not like some of the lack of rigors I was seeing in physics.”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source
“Said about him is accurate. I had the pleasure of interacting with him as a student and later on, as colleagues writing papers together and so on”
2021-07-26 · Lex Fridman Podcast · #204 – Cumrun Vafa: String Theory · IDENTIFIED FROM THE TRANSCRIPT · source