String Theory, Quantum Gravity and Black Holes (Or, Are We Holograms?)

knew, can you give us an idea of ​​what is correct? So yes, this article by Einstein Rosan is basically an article trying to better understand the geometry of the sh. of the solution, yes, but what they discovered is that the geometry really connects two separate universes, in some way it is a connected geometry, a kind of wormhole, as you said, between two universes, but it is not actually a wormhole. traversable worm, so it's something you can't use to send signals. Yes, and the idea is that this geometry should be seen as two separate

black

holes

, so you have two universes, two

black

holes

in each universe, but the

quantum

sites of these black holes are entangled, and that entanglement creates that connected geometry.

Um, so that's the idea and well, this idea has been made more precise using these entanglement formulas. The original formula was due to Ru and takayanagi and was improved by many other authors, so now we understand a little. better how does this work um I mean would you? Is it too rude to say that whenever there is

quantum

entanglement there is some kind of wormhole-like geometry, right, yeah, right now I think it's too Co to say this um, so the thing is it depends on what call geometry. If U, if by geometry you mean a large space described by Einstein's equations, then the answer is no, it's true, so particular patterns of entanglement only correspond to those geometries, but not to anything.

Of course, now there is an open question which is: well, is there a generalization of geometry in which this would be true? When it appeared, it suggested a revision of some aspects of Space-Time, for example, while we were discussing, the number of dimensions of space increased from the naive value of three to nine or ten spatial dimensions, depending on whether it is

string

theory

in the original Incarnation or in the The theoretical 11-dimensional M super

gravity

that you referenced earlier in

string

theory

also suggested that these extra dimensions would have a rich geometry coiled into a strange shape called the cabia shape that we also referenced previously.

Shall we go further now? It's string theory. and work on quantum

gravity

more generally, are you suggesting that space and time or spacetime itself is not a fundamental ingredient in the nature of reality and should instead be considered as some kind of emergent feature that It's only really relevant in certain environments, but more fundamentally, we should be able to talk about physics in the absence of space and time. Well, I think in this notion of CFT ads or these dualities, at least some directions of space or maybe all directions of space, are emergent. in this sense, in the sense that they are not in the fundamental description, that involves some elbows for example, and then you make the elbows interact with each other, you get a higher dimensional space, we don't have good examples that we have time for enough. uh, I think the inside of a black hole is a situation where we have some kind of time.

The direction in the interior is, in a sense, immersion, but we don't understand it well enough for that to be part of the things that we don't understand and hopefully we will soon understand um and yes, it follows from this description that the description of the Quantum mechanics is more fundamental and Space-Time seems subordinate or emergent, what is ersion is certainly the uh Space-Time which is governed by Ein equations, so it only arises in certain circumstances. Now the force of the description is a description that uses this Space-Time and perhaps some modification of that space-time, so it suggests that there could be a theory that generalizes the notional Space-Time from which perhaps the limit theory could em or something like that.

I haven't given up on a theory that is described as involving spacetime or some internalization of spacetime like we have in string theory, but once you have duality, say ADF CFT where you have these two distinct descriptions , one says that it involves fewer spatial dimensions than the other, so these geometric configurations within which the description of the theory of quantum mechanics, the quantum field, lies, are very different from the geometric configurations that say that the description of gravitational and string theory is Maybe it is enough to say that space at least is not fundamental, because if it is, what would be the fundamental description?

It can no longer be described in terms of space-time. Well, it could be that if you have the inner spacetime and you add up a lot of spacetimes or you consider the full quantum theory of those spacetimes, then you could get the same answer, so it's a bit like uh, you know the so-called transformation FIA, which is a way we have of representing signals, so you can give how the signal changes over time or you can give all of its frequency components. Yes, we know that if we are describing a sign. we can give either of these two descriptions and they would be equally valid and um, so it could be, I think it could be something similar, we can have either of the two descriptions could be valid and correct by saying if you use the full quantum description on the quantum side and add all the geometries, maybe everything combines in a way that produces a single geometric description, at least in principle, right, yes, no, yes, and there are some very simple examples in two dimensions. where something like this has been, I mean, it's done and you get some kind of boundary description, yeah, so the final question here, you know, I mean, I've been fiddling around working on these ideas, you know. , since 1984 85.

I have been doing what you mentioned since 1990. Are you happy with where the developments of the last 30 years have taken us? I mean, have we come as far as maybe you would have hoped when you started in 1990? Well, I certainly hope that they were more advanced than we had, I would hope that we had an experimental prediction that we can measure and test and some prediction for cosmology perhaps and on the other hand, I think there have been a lot of advances on things that seemed impossible. o Out of your reach, you know well, especially in this area of ​​the black hole, certainly or even regardless of the understanding strengths of the black hole in very strong coupling, etc., so there were many things that were definitely mentioned as problems open very important in you.

I know it in the 80s or early 90s and now it has been understood and yes, I hope the same thing happens with the problems we are discussing now, like the interior of black holes. I think it's an issue that hopefully there will be a lot more progress and I think. I think there's been some progress through these entropy formulas and hopefully we'll see more in the future so overall I'm optimistic yeah I think it's an exciting area and well it's a long shot in the sense That it's, you know, a very ambitious program, I think it's leading to interesting formulas, interesting mathematics, interesting new ideas.

I keep hearing new interesting ideas, so I can't even keep up with the new interesting ideas that they're proposing, so it's, it's, the field is moving and uh, yeah, I think there will be, yeah, and in the end, at the end end, that's the right barometer, you know, a theory that gets stuck, oopi, doesn't change, lets you know, force theories set in stone are malleable and develop quickly. Extremely exciting collection. of ideas that we hope will ultimately come together so that you get a full understanding of this theory and, going back to our initial questioning, give us insight into the nature of the Big Bang and how things really began or deep inside of a black hole.

I think that's ultimately where we're headed, so Juan, thank you so much for the fascinating conversation on everything from Einstein's unification to black holes, holography, CFT ads, duality, and the emergent nature of space time. It's been a pleasure to talk. with you and thank you very much for joining us, yes, it's great to talk to you and well, greetings to everyone listening, excellent, thank you all, that's a summary of our conversation with Juan Malesa, a very quick tour of the latest that we really went. It all goes back to 1968 for a moment, so over 50 years of development in string theory, which is still a vibrant, exciting, fast-moving field, and we just have to acknowledge that certain questions we hoped to have answered today as definitive verifiable proof. prediction that we'll just go out and see whether or not these theories are confirmed with data that we would hope to have that today, but we don't, but we're still working hard to get there, but we've gotten information about black holes. in nature, space-time and the deep connection for which the wand is responsible between our understanding of gravity, on the one hand, and a theory without gravity but with quantum mechanics, that is, a quantum field theory on one hand. delimiting surface of an inner space-time, is such a remarkable and powerful vision. which has really set the course of string theory research over the course of over 20 years and we suspect that this is a key to understanding the true nature of gravity and the matter of space-time, so just Time will tell where all this goes, but it is certainly an exciting and fast-moving field.

If you are interested in learning more about this topic, please subscribe to our YouTube channel. We had another live discussion here in New York City with several of the leading string theorists, Ed Wht, David Gross, Andy Strominger, where we covered something similar to what we did with Juan, but it's great to hear a variety of opinions on the developments that have characterized string theory research over the past 30 years. We will launch that program. I don't know, probably in the next few weeks. I think we're also going to be launching a show about artificial intelligence that we did at that live event in New York City, as well as a whole host of other shows in addition to these live conversations, so if you want to know what's going on subscribe to our YouTube channel and also to the World Science Festival newsletter to be alerted when these programs are live and available.

Well, that's all for now from Columbia University to New York City's Brian Green for the World Science Festival. Thanks for looking