The big question was to try to understand the physics, fundamental physics, behind the information storage capacity of a black hole. Now, the point is that black holes are the limit of the information storage per given size. So if I want to send you a message in a box of a given size, then I

can keep putting there information bits until this message becomes a black hole, collapses into a black hole. This is the limit, because if I try to put more, then this message will just increase. I will get a bigger black hole. So black holes are the biggest limit of information storage per given size. So you can think of a black hole as a sequence, as a very long message, a sequence of zeros and ones.

And the longest message per size, again. But another amazing property, which is highly non-trivial for a black hole, is that to go from message to message in order to rearrange the message, it is the cheapest system. This is incredible. So in other words, think in the following way.

Think about the book, right? So to create a book, it may cost some energy. And actually, a book itself may be very heavy. Then in this book, you store information, because you write. But you can write one message, then you can erase it, and go to a different message. This procedure of going from a message to message,

rearranging your qubits of information, it always costs energy. So the black hole is the cheapest. So the black hole is cheapest in rearranging the message. So in other words, the black hole of the given size, of the given mass, has a huge number of copies, which differ by this inner message.

So it's very hard to distinguish them classically. You have to wait a very long time. This is the price to pay for a big message and for a cheap message. But nevertheless, black holes are really incredible from the point of view of how cheap it is to rearrange the zeros and ones.

And so the idea was to understand physics behind this, maybe in terms of some general phenomena, and then see how unique black holes are in this respect, whether there are other systems of nature that can process information in the same way. Let me describe the method, right? Now, we are theoretical physicists. And we also detail this fundamental physics.

And the topic that we are trying to tackle, understand, essentially, we are moving in dark, right? So we have certain well-established facts. We are trying to understand what's the underlying fundamental physics behind these facts.

So we are trying to understand black hole information storage in terms of some phenomena of nature, OK? Then the way it works, you get an idea. And the idea is that this phenomena of nature is quantum criticality of black hole constituents of gravitons, OK?

Now, once you have this idea, then methodology is the following. First, you try to understand consequences of this idea. And secondly, you try to kill the idea. Actually, the two are connected, because you can have, once you derive consequences, you can see that these consequences contradict to some obvious facts. Then you are killing the idea.

Or you try to kill the idea in a different way. So basically, this goes in parallel. So in the same time, you are trying to develop the idea. From idea, you want to develop it into a theory, OK? Something that you can work with, calculate something, predict something, and simultaneously think about the loopholes, OK? What could be that could kill this idea?

So that's the methodology. What is new in our research is that we have understood the fundamental physics behind black hole information processing and information storage capacity in terms of very general phenomena of nature. And this phenomena of nature is so-called quantum

criticality, in this particular case, of attractive bosons, of attractive particles of Bose-Einstein type systems. This is the key finding. So this means that we have a microscopic theory based on this idea, this central idea, how black holes work as quantum computers.

This is the key. Now, this quantum criticality is precisely what is responsible for appearance of the cheap qubits, which were total mystery before, OK? Before, this was completely, even for us and for everyone, unimaginable. How can you have a system with so cheap quantum qubits? I mean, qubits are quantum qubits, of course,

information bits, quantum bits. And now we understand this in terms of this quantum criticality. Now, what is quantum criticality? Quantum criticality is the transition, it's a phase transition between different regimes of the system, OK? You can compare it with a group of people or a country. Any system with many, many constituents

can exhibit this type of transition from one regime to the other. And at the transition point, certain things become very peculiar and unusual. And things that are unimaginable in when system is in the stable equilibrium become possible when system is at the transition point. And this is very similar to this comparison.

If you have a big country, a stable country, normally it's not easy to change hierarchies. People have to work very hard to go up in the hierarchy. But if a country is in the transition point, revolution or something like that, then to change hierarchies becomes very cheap, energetically cheap.

And this is also the common property of systems of nature. So it's not just about countries, but this is also true in generics. There is a big class of systems, including black holes, which are at this transition point. And that's why they have cheap qubits appearing. So this is the key, and this is new. This finding has relevance at least in two directions, OK?

Now, first, we are working in fundamental physics. And we are trying to understand nature. The point is that we cannot understand nature of elementary particles. Now, nature, we want to understand at very high energies, at short distances. And we want to understand what are the laws of nature,

at very high energies, let's say, right? This is impossible without understanding black holes. Why? Because gravity is an interaction which is universal, and gravity is an interaction which is becoming strong with energy. So high as the energy in particle collisions, gravity becomes more important. If you want to build a more and more powerful microscope,

gravity will inevitably play more and more important role in this process. And most powerful microscope that you can build, there is a limit to it. Because fine sooner or later, you cannot resolve. Distance is shorter than the Planck length. And you try to construct a microscope which

is more powerful, it will collapse into a black hole. It's the same thing, OK? So in other words, the black holes are the end point of any high energy particle collision. This is commonly accepted, this view. But then this is telling you immediately that without understanding black hole quantum physics or black holes, fundamental physics or black holes,

we cannot understand nature. Because there will be a region, high energy region, domain of nature that we will not be able to describe without being able to describe black holes quantum mechanically. So therefore, you see, it's absolutely important for virtually every problem that every question that you want to pose in high energy particle physics will bring you finally

to the understanding of black holes. And therefore, this is the key. This is one very important thing. It also has implication in cosmology. Why? Because universe, we come from big bang. And laws of physics, in the early universe, were high energy laws of physics. Because back in the past, the universe was hot.

Elementary particles were very energetic. And again, for understanding history of the universe, we have to understand physics at high energies. And again, we cannot do it without understanding black holes. So in other words, how universe stores information, for example, we cannot understand without understanding this type of physics.

So this is as far as fundamental importance is concerned. But there are also implications. Because this opens up a new direction of the research. Why? Because now we understand that black holes are not unique in the way they process information. There are other systems which exhibit quantum criticality. And these systems you can manufacture in laboratory.

And they essentially are doing computation according to the same rules that black holes are doing. Now, this is very important, because first, it demystifies black holes. Because now we understand that you can have systems that you can manufacture. Moreover, you can study black hole physics by observing these systems. So you can borrow computational skills from black holes,

realize them in real labs, laboratories, but also backwards. You can read certain phenomena in laboratories which you were not suspecting before existed. And now we can say, oh, there is a new phenomena. Maybe go back and look in astrophysics. Maybe black holes exhibit similar type of phenomena. And let me look for it.

So it works in both ways. Opens a new direction of research in which you can sort of use the same phenomena of nature, but in different systems. And some of the systems are much more accessible. And this is very exciting. The question is how to continue this research. So we are thinking in a few directions.

One is, of course, fundamental research. So we must understand better and better, work out this theory in more details, try to understand how physics of black hole quantum computing works, both in gravitational systems as well as in condensed matter systems, generically in the systems with quantum criticality,

as I said. This is one theoretical research direction. It has many sub-directions. Another direction is to try to manufacture these type of systems in laboratory and make direct observations on critical systems from the point of view of black hole-based quantum computing.

This is very exciting. Of course, here, I'm a theoretical physicist. We need help from our experimental colleagues. So we are discussing with them, trying to understand what would be the right systems of nature in which we can do this type of experiments. There are a few candidate systems that we are thinking about, in particular, cold atoms.

Because it seems that in cold atoms, we can manufacture the systems with attraction and with criticality. So we can sort of repeat the same physics that takes place in the black hole quantum computing. And this is very exciting research, essentially experimental.

And there is third direction in which we try to understand what can be seen in the sky in real black holes. What are the predictions from this inner structure that could be observed by astrophysical observations? So this is another very interesting question. And again, we need help from our observer,

astro observers, from our colleagues that are doing astrophysical observations. This will be really very exciting to see a trace of or a signature of black hole quantum hair in astrophysical observations. OK, we are in the process of studying it,

trying to understand what could be seen. And yet another direction is cosmological. So try to apply these ideas to cosmology and see, just in the same way as black hole encodes quantum computational messages, whether the universe itself, which is very much like black hole, early universe,

how the early universe was storing quantum information. And whether one can read out some of this information, which is now stored in fabric of space time. That's yet another direction. So it's very exciting.