Spiros starts with a magnetic field, an electric current, and a voltage appearing in an unexpected direction. Then he takes me from the quantum Hall effect to topology, entanglement, and the possibility that the universe works like a hologram.

I try to keep up with Mexican jumping beans, scratch holograms, and a light bulb. We explore why a messy experiment can produce astonishing precision, how a system’s global structure constrains what happens locally, and what it means to see the world from a particular point of view.

Transcript

Spiros: The quantum Hall effect is like a murmuration. It's an emerging phenomenon. It is the infinite in the infinitesimal communing. Specifically, topological quantum order is what we call information that exists at the boundary of the multiverse — if this is a hologram, the information is on the boundary, the 2D surface, and the 3D aspect of it is just how the lasers decode the information that may look gibberish on the surface. But then it gives the extra dimension, allows it to be decoded, decrypted, until you see the thing — you're like, that is amazing. That's what that one is: the quantum Hall effect. That's why it has all these Nobel Prizes. It was the very first serious macroscopic quantum phenomenon that humanity ever discovered, and then tried to understand.

And why did it take so long for us to crack this problem?

Pablos: What do you mean, how was the Hall effect discovered?

Spiros: The Hall effect specifically was discovered by Klaus von Klitzing. Well, the Hall effect — the original one — was discovered in 1880 by Edwin Hall, who was a graduate student at Harvard at the time, and he had this idea that Maxwell was full of shit when he was saying this is how an electric field has a particular relationship and has a force towards a magnetic field. He wanted to understand: the relationship between electric and magnetic field. And Maxwell had his own version of it in the textbook. Edwin Hall was, I don't think that's right, I want to test some things out. And developed some experiments: all right, if Maxwell is right, then this shouldn't work, this shouldn't happen, I shouldn't be able to observe this thing.

It was a null hypothesis thing, but then he observed the thing and he's, well, that cannot be the explanation. I want to figure out what the explanation is. Specifically the idea is that when you have an electric field, electric current going through some conductor or semiconductor — but at the time, conductors, because they didn't have semiconductors — then if you have a magnetic field perpendicular to the surface, you're going to start to see a deflection of electricity, of the electrons, towards one side. That's the little detector that we talk about. Because that's how you detect even small magnetic fields: by seeing a voltage change across the horizontal direction, even though in vertical is the way that the electricity is traveling. It's just going down this path.

You actually see voltage change orthogonal to that, and you're, oh, it must be that you're bending. If you put a magnet underneath conducting material that you can put current going down—

Pablos: We'll see less current arrive at the other end.

Spiros: You will actually see the same amount of current, because it's just so microscopic. But what you will see is you'll start picking up a voltage where they're supposed to be no current going in the perpendicular direction. You're like, how the hell are electrons going — not going straight and going to the left. Magnetic field is right, acting very specifically. If you were to put the magnet not at the bottom but at the top, then it would start deflecting in the opposite direction. And this is the FBI rule of force, current, and magnetic field — I learned the Lorentz force — and that first time that it was observed, it was, oh, there is a relationship here. So Maxwell didn't think there was a specific relationship.

No, he thought that something else was happening: that the actual electrons in the conductor were shifting, and it wasn't the electrons in the current itself that you applied externally that were actually being moved. That was the thing. And so that's what Edwin Hall figured out. Big deal. But then Klaus von Klitzing, an Austrian experimentalist in Grenoble, France in 1980 — but two months before I was born — this guy was trying to understand how semiconductors can survive. Now we're thinking computers, chips, silicon — what happens if you put them in outer space conditions or under extreme magnetic fields, so very cold and high magnetic fields, teslas. It's basic science but good for technology.

You need to know microchip and MRI. Maybe it was the DoD or something. Like in France, he's, I need to know what happens. We need to know if it breaks down, if it bursts into flames. And what he saw was that unlike what Edwin Hall had figured out before with low magnetic fields and just room temperature basic stuff you could do at Harvard at the time, it was a linear relationship: the stronger the magnetic field, the higher the voltage, the conductance. You crank up, double the magnetic field, zip in between continuously, just a straight line as you kept going — the stronger the voltage, the conductance you would see. But that's not what von Klitzing saw. He saw plateaus.

At some point he started seeing that you were cranking up the magnetic field strength, the stronger and stronger magnet, and there was no more voltage increase. It would just plateau. It would just saturate.

Nothing is happening — as if the electrons stopped moving, or you got them all, or something like that. But that wasn't even it. He was like, this is very weird. How the heck is this? And again there would be a jump. So we go from one plateau to another plateau when you cranked up enough the magnetic field at the new value, and then it would jump up to a new value of conduction stages.

It was stages, steps: step one, step two, step three. The first part of that, when you had very low magnetic fields, it was just linear, just Edwin Hall, sure. When you get a little bit higher and the temperature dropped for the material, then it went quantum. The hell that means. And the funny thing is that the steps — the height of that step — was very precise: integer multiples of e squared over h, e being the charge for the electron.

And h being Planck's constant, one of the most fundamental constants in quantum physics — the most fundamental, the one that tells you that energy is Planck's constant times frequency. And so it was very weird that it was precisely one times that, two times that, three times that, four times that. You're like, what the hell is going on? He won the Nobel Prize in 1985, because with this dirty experiment — he wasn't even trying hard to do this — he kept getting the most precise values for the fine structure constant of the universe.

Which is this e squared over h. Nobody else could even come any close to that. It's like, how the hell am I getting 12, 13 digits of precision? It's something that is like a dirty experiment. And if quantum physics is involved, how the hell is quantum physics surviving? With quantum computers now you need to be so fine tuned, you need to develop quantum error correction, all that stuff. He was seeing a macroscopic quantum phenomenon. That's what the quantum Hall effect ended up being. He was microscopically measuring conductance with voltage meters, and somehow was able to define one of the most precise fundamental quantum constants in—

Pablos: Nature. This isn't like resonant frequency of electrons is causing it.

Spiros: It was something else. And it was what you were saying before. It was when you're a conductor in a symphony — so resonance in some ways — that there was a conductor that was telling every electron how to behave. And this is a vast universe for these electrons, because this is microscopic semiconducting films, that somehow every single one of them knew how to dance with every single other one so that when the new tune appeared, the new value for the magnetic field, they all were up.

And now we're awake again. Let's start dancing all at the same time. And the amazing thing — and I will send you the Scientific American article I wrote about it afterwards — is there's something much deeper going on. Forget even about the quantum Hall effect. That's good stuff. But microscopic quantum physics: how the hell can you have something that is at the level of quantum precision, but is a reflection of something much larger? And what I realized is that this is where the constants of nature come from. What is a constant of nature — one that is not the thing that we just set? Like the speed of light you can set to one, it's just the ratio between dimension of time and dimension of space, that's it.

But what one second versus one meter — it's just a currency exchange factor. You can just set it to one. Planck's constant you can set to one. But there are some things that you cannot quite set to one that seem to be composite and interesting.

But they come from somewhere. And there is no place in space or time in our universe where you can just go and be, there's a little box over there and I could turn this fine structure constant from whatever its value is even one percent higher or lower. There's just no way for anyone. It's just not possible to do. How is that possible? Think about it for a second. We have access to anything else but these constants.

And they are everywhere. They're at the most minuscule scale or any large space-time region. You can't do it. There's nowhere you can go, no experiment you can do to mess this up microscopically. And this is the hint. This is exactly what we were doing for these electrons inside of this semiconductor. They were experiencing one time e squared over h, which is the fine structure constant of the electrons around them in the rest of the universe. But then when you cranked up the magnetic field too strong, then they went into a different universe. And it was not twice as strong. They could actually get access to twice the same fine structure constant, or three times, or four times.

They started getting long range entanglement, much longer range fundamental structure for what it meant for their quantum fields to give rise to these local excitations we call electrons. They were being part of different macroscopic universes. Why could we do that? Because we had access to the boundary of their universe. The way we were doing it is by bombarding their whole universe, which was like the semiconducting film, with something like god powers — a huge magnetic field. We cannot do that, because we are inside of that thing. You have to be outside of it to change its topological nature. That's what we call by topology: something that is different from geometry. The local geometric structure of stuff, the curvature, doesn't matter.

Topology has to do with the things that don't change — the universal infinite structures of a shape, a mathematical shape, or in the universe — that does not change under continuous deformations, which is what we can do when we're humans and we're doing experiments in only local region of space or time. And so that's what the constants of nature are. They are reflections — what we call topological invariants — like the quantum Hall conductance that got them all these Nobel Prizes. It was a topological invariance. And you may know already something like that: the average curvature of a two-dimensional shape is a topological invariant. The average curvature of a sphere and that of a tube or anything else that does not have a hole in it—

Pablos: Is exactly the same. This is crazy.

Spiros: Even if you get a bagel, even with a little sesame seeds, if you were to find the average curvature — you go and you calculate it maybe in a computer 3D rendering or something — and you're all right, what is the average curvature, which is the total curvature, the positive, the negative, the zero flat curvature, divided by the surface area. If you have something else that is another perfect torus as we call it, or a bagel, it will have exactly the same average curvature.

Which for a torus, for something with one hole, genus one as we call it, turns out to be exactly zero. Every single one of these one hole structures have exactly the same average curvature. Geometrically, the local curvature could be anything. Yet somehow magically it all adds up. It has to. If you do something here, the other one has to mess up. Something has to happen in order for the total to be zero. No matter what, the global tells the local how to behave. It's pretty crazy because usually we think that the local information is what creates the global picture. But there are some things which are invariant. Nobody can touch. Constant throughout the whole space. That's what this whole thing was about.

Pablos: To pick this apart quickly here.

Spiros: I think, in case I was wrong with a minus sign somewhere.

Pablos: With this Hall effect thing, if I take Mexican jumping beans and I put them in the palm of my hand, I control their environment. The heat from my hand warms up those little worms. They start squirming around. The things start moving. So I'm controlling that environment. You're describing experiment where we're putting electrons in an environment that doesn't exist in nature that we know of, but we control variables — or most of them.

And the extreme magnetic field is getting these electrons to go out of bounds from their normal. Normally they go from zero to ten on a dial. That's right. And you're, nope, we're going to—

Spiros: 100. That's right. To 11 plus. And so now they become part of a different reality. They become part of a space-time that has a different fine structure constant. And think about what space-time is made of, which is obvious: it's made up of entanglement, little wormholes. I was joking about the obvious part. But it is what we call a tensor network: a network where the nodes are the quantum nodes that carry the information, the state, the local state, bits of information.

But qubits, quantum bits, or qdits — higher dimensional things — could be even infinite dimensional for every node. But then you have a relationship between this one over here and another one over there. There is no concept of space or time yet. It's just a graph. You can think of the graph as even not being planar or finite dimensional. The degree of each node could be infinite as well. You're embedding the whole universe into the relationships between the nodes.

And the edges have a weight, have a strength to them, and that strength is what we call the strength of the entanglement between the nodes. So as the state of one of them changes and goes from on to off or something like that, then you look around and you're like, which ones did it affect and how quickly? Because you're teleporting the information. So even the question of how quickly — it's not even faster than the speed of light. But there is a statistical how quickly. Why?

Because there is no single graph or network of relationships. There's an infinite superposition of them. And if in most of them this node changing its state changed the bunch of the other ones that you consider now, oh, these are the neighbors in half of the universes, but it did nothing to these ones the other half, then it will feel — you need to take a moment. The moment has to pass until this decoherent multiversal spreading recoheres and you find yourself in the half of the universes where it did affect these neighbors.

It's a statistical speed. And even the speed of light, because it's an emergent thing where things can immediately connect and affect each other because there are wormholes. But they're so tiny that information only may be able to traverse. But even if it can, you don't know which thread you need to send the information through and which one to be picked up on the other side.

Pablos: In quantum entanglement: is there latency, or is that set to zero?

Spiros: There is. It's almost epistemological. There's something known as the Lieb-Robinson velocity, which is an emergent speed of entanglement. It is like Kevin Bacon — how many degrees of separation you have.

Pablos: Is it presumed to be non-zero?

Spiros: It's only from our point of view. So non-infinite you mean, because the speed is basically infinite from its own point of view.

Because it's just an immediate change of state crystallizing the whole thing. But from our point of view we have to observe microscopic changes happening, which means a lot of them. You need to get enough statistical significance to be, oh, these different universes they all had the same effect, even though I also was entangled or related as an observer with a bunch of them where nothing happened. So I need to see enough of a signal to be a photon came, or a piece of information showed up.

And that's the thing that is crazy when you realize that our point of view is all there is. This is all there is. The whole world exists. We were talking about the general anesthesia. It wasn't just a thought experiment. The world disappears even though it's of course there. And you're, come on, doesn't disappear when I go away. Or from your point of view it goes away. You don't even exist anymore. And you can say, well, but the world always exists from the point of view before I went out. No it doesn't, from most point of view — non-human or things with faster frame rate or higher resolution. From an electron's point of view there is no world. It is also the smallest part of our universe.

Even a centimeter is like a whole galaxy for it, if it even thinks of itself as a point particle versus just an excitation of a quantum field.

Pablos: Going back to the hologram, because I think a lot of people don't necessarily relate to how a hologram is produced. I don't know if you've ever seen this.

Spiros: 3Blue1Brown.

Pablos: Do you know what a scratch hologram is?

Spiros: No.

Pablos: Oh my god, this is fucking amazing. This guy I met years ago was washing his car. Then in the sunlight afterwards he saw his hand floating on top of the car, like a hologram. And the reason is it's 2D plane.

He was making circles. From that he learned he could make holograms by creating circular scratches in acrylic. Then he started doing little art projects this way. So you can make a pixel. X and Y is controlled by where you put it on the surface. Z is controlled by the radius of the circle. Very cool. And he was inadvertently doing this by just wax on, wax off, wax on, wax off. But apparently not using wax — using something that's scratched his car.

You could simulate this with some grit in your car. He was doing it with a compass and a sharp tip. And then you could put scratches in acrylic and then you could create a hologram that way. And it might be a really interesting way to demonstrate, because what you're describing is: if you look at the circles on the acrylic, you don't see a hand. Nothing makes sense. But if you shine light on it, then it creates that.

Spiros: That's basically how even Feynman understood quantum electrodynamics. And even the little iridescent that you see on a bubble — it's all because of the interaction of light and the different wavelengths of it, as they reach your eye, depending on the medium that they're interacting with. It's a quantum Fourier transform. It's just separating into the individual frequency and then recombining them in new interesting ways depending again on your point of view. And that's the craziest thing I think I've realized about how the universe works: is that we bring the universe into existence by suppressing, filtering out most of what is going on. The concept of no thing.

Pablos: Of nothing. We call it nothing, but of no thing.

Spiros: The concept of that is the quantum superposition of all possibilities, of all things. And you filter out most. You suppress most of it. Distractively interfere with most. Because your point of view first of all has too few dimensions to capture most of it, and also its orientation in the few dimensions that you have creates an environment that is hostile to most of the things that are coming towards you. It's almost like Bose noise canceling.

Pablos: When I was a kid it was so weird to me to understand that black was the absence of color and white was all color. And just getting your head around that, and then thinking about learning the difference between additive and subtractive color schemes. If you're drawing crayons on paper it's actually subtractive, whereas a television is black, but it's additive — it's adding color. And so maybe some version of that is true. The whole world — I don't know how many qubits are on my fingertip. Billion. And all of them could be anything but a fingertip. But they're filtering out everything that is not fingertip.

Spiros: It is our relationship to it, the state of our consciousness, and all the filtering, not just as the raw data comes in. Then most of it is filtered, but the encoding and decoding afterwards — that's even more so, I think, in physics and in mathematics, where we are seeing the deeper we go to try to understand what is really going on besides even the world around us.

The secret is in what we call representation theory. And it was used originally to understand how crystalline structures work and material science. But representation theory is just something way more powerful. It's this idea that we only know the world from a specific point of view and through the relationship of that point of view, entangled, to another one. Imagine that the state of your being is uncorrelated, unentangled completely from the state of some other being or some other thing that can change. Will you even know that this other thing exists? You wouldn't even know. It'll be a separate universe. In other words, the strength of the entanglement — if it is zero, it is as if it is infinitely away from you in both space and time.

No matter what happens to it does not affect you. You're not aware of this even changing, let alone existing. But when the entanglement becomes maximal between you and that thing, you become one thing that only looks like it's separated through intermediate space or time. You're actually one superstructure that others from the outside cannot perceive as a single object. Two entangled qubits that are sent far away from each other have immediate state change relative to each other, even though it may take us time to send a light beam to decode what just happened.

Because they are the highway. If you go from here to Highland Park where I am, you have to go through the 110 at some point. The highway is already there between both spaces. And you can think of light the same way: the grooves on top of space-time through which matter, electrons and other particles, electromagnetic particles move through. That's why you cannot travel faster than light in that way. Because you cannot travel faster than the thing that is already there, the highway. And so even the curvature of the highway is what makes you feel, oh, this electron now just feels some force and it's moving this way. Light doesn't exist. It's crazy — you go to empty space, vacuum, no matter how strong your laser, you will never see light.

You only see light through intermediaries. All you're seeing is a state change of one electron that is entangled with another one — the one from the wall to the one in your photoreceptor cell — that then does this cascade.

Because of entanglement between them. And you think of it as, oh, photon is what excited this one, was put back out into the universe and came. No. It is entanglement — an entangled network of these nodes that says I just changed my state, you should pick this up. And the things that you see are the ones that you're actually entangled with. We're entangled with everything.

Which is weird. It's known as the Reeh-Schlieder theorem, and it makes sense because it is possible if you spend enough time or you move enough in space to experience something, even if you should be able to go back in time against the arrow of time if you really know what you're doing. But that's hard. But the idea is that epistemologically, being entangled with everything else simply means that you have the ability to observe or connect or get to know everything.

Pablos: Let me try this. I got a light bulb. When I look at the ceiling I see some light that's clearly coming from the bulb. So what you're saying is, in the quantum physics version of this story, there's not a thing called a photon coming out of the bulb, bouncing off of the ceiling, and then traveling through space into my eye and pinging a little receptor. What's happening instead is the receptor in my eyes entangled with what? The bulb or the ceiling or what?

Spiros: You can say the atoms, the electrons on the wall, which themselves are entangled with the atoms in the light bulb, the electrons. And that's what you're seeing. You're seeing a cascading of that entanglement network we were describing before, where one of them goes up: My state is this. Then the other ones who can actually feel that change. Because there are other things — if you have like the perfect black material or something, it just absorbs. Nothing is reaching you. Sorry, I just absorbed this connection. There's just nothing for you to bounce off of.

Pablos: Presumably somebody must have figured this out. Because solar panels work, I'm presuming this entanglement—

Spiros: Is between the sun and the electrons and all these things in the sun all the way down, and the material is being transferred in this entanglement process. Like the only way you can see light is if you have a laser beam so strong that it disrupts space-time itself and creates particle anti-particle situation. Oh, it's almost as if again you break up the freeway itself and you get to see what it is made of. Then something new comes up.

But there is just light. Every particle that is force — the bosons are gauge particles. They are useful fictions in physics, because you can use them to be able to tell a simpler story, but they're not there. Well, it gets funnier again, because you can say, well, matter at least is here. These are like the spin one half particles. These are the fermions. These are the things I can touch. Why? Because the Pauli exclusion principle works for them specifically.

They cannot be at the same place at the same time unless they're maximally entangled, which means like the internal degree of spin. But even then, if you look at all the quantum properties of it, if there is a pressure — this is what we call the anti-symmetric part of the universe — where if they could be on top of each other they would just annihilate. Why? The same way that if you have a times b and b times a, the anti-symmetric part of this product is ab minus ba. What happens if a is equal to b? That becomes zero. It becomes a squared minus a squared. That's zero.

The quantum amplitude for that thing to be observed, which is the probability of you seeing this happening in chemistry or in the universe, goes to zero. And so that's where it comes from. These are the elements of the world that don't exist all at the same place at the same time. Always require some internal pressure in mathematics.

That pressure comes from the anti-symmetric part of a composition of experiences — the ones that cannot be when you commute them, when you go from this one first and this one second to the other way around. They pick up a negative sign. They pick up this phase that makes this anti-symmetric and says, if you had two things that are the same and you switch them, they pick up a negative sign. The only number that is equal to its negation is zero.

And that's where these things come from. So in order for them to exist they need to create space for them. I need to be over here in space and over here in time. You cannot collapse everything. With photons you can put more and more and more and more of them, an infinite number of them, infinite energy.

Pablos: Zero is not enough. You need a null value.

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Recorded on May 4, 2025