Do Electrons Ever Break the Rules? Inside the VIP-2 Experiment

<v Speaker 1>Welcome to the quark Side. Quantum Physics Podcast, an exploration
<v Speaker 1>of the fundamental structure of reality, where quantum laws govern matter, energy,
<v Speaker 1>and information. Here, uncertainty is a feature, not a flaw,
<v Speaker 1>and understanding begins at the smallest scales.
<v Speaker 2>All right, before we get started, I want you to
<v Speaker 2>try something for me.
<v Speaker 3>Oh, okay, a little audience participation. I'm in right now
<v Speaker 3>wherever you are, just I don't know, reach out and
<v Speaker 3>touch the table in front of you, or grab the
<v Speaker 3>arm of your chair.
<v Speaker 2>Okay, I am tapping the desk right now. It's solid,
<v Speaker 2>cool to the touch, definitely real.
<v Speaker 3>Exactly, it feels solid. Your hand stops, You don't fall
<v Speaker 3>through your floor, your coffee cup doesn't just phase through
<v Speaker 3>the table like some kind of ghost.
<v Speaker 2>Right. We take this for granted.
<v Speaker 3>We take it for granted every single second of our lives.
<v Speaker 3>It is the basic fundamental fact of our existence. Things
<v Speaker 3>are solid. But here's the question that, and I'm not kidding,
<v Speaker 3>keeps me up at night.
<v Speaker 2>Why why is the world solid? It sounds like a
<v Speaker 2>question of five year old would ask, doesn't it?
<v Speaker 3>But why it does? And it's a great question. But
<v Speaker 3>the more you know about physics, the right the weirder
<v Speaker 3>that question gets because we know if we zoom in,
<v Speaker 3>and I mean way way in, that desk isn't a
<v Speaker 3>solid block of anything, not at all.
<v Speaker 2>It's mostly empty space, a cloud.
<v Speaker 3>Of atoms, and those atoms are what ninety nine point
<v Speaker 3>nine percent emptiness? Oh more than that, it's more like
<v Speaker 3>ninety nine point nine nine ninety nine percent. If you
<v Speaker 3>imagine an atom is the size of a huge football stadium. Okay,
<v Speaker 3>the nucleus would be like a marble sitting on the
<v Speaker 3>fifty yard line, and the electrons would be these tiny
<v Speaker 3>little gnats buzzing around in the absolute nosebleed seats and
<v Speaker 3>everything in between void nothing right. So logically, if matter
<v Speaker 3>is almost entirely empty space, why doesn't the entire universe
<v Speaker 3>just I don't know, collapse into a single microscopic point.
<v Speaker 3>Why doesn't my hand just pass straight through this table
<v Speaker 3>like smoke through a screen door.
<v Speaker 2>Why can we touch things?
<v Speaker 3>Yes? Why?
<v Speaker 2>It is a profound question, And the answer isn't just
<v Speaker 2>because matter is hard. The answer is actually a rule,
<v Speaker 2>a very specific, very strict rule written into the operating
<v Speaker 2>code of the universe.
<v Speaker 3>The rule that if it were broken, even just a tiny, tiny,
<v Speaker 3>bit would mean that chemistry, life, stars, basically everything we
<v Speaker 3>know and are would instantly cease to exist.
<v Speaker 2>You're talking about the poly exclusion principle, the absolute hero
<v Speaker 2>of today's deep dive. We are talking about the very
<v Speaker 2>bedrock of reality. But here's where it gets really interesting
<v Speaker 2>and honestly a little bit nerve wracking.
<v Speaker 3>Go on.
<v Speaker 2>We assume this rule is perfect, we assume it's absolute.
<v Speaker 2>But what if it isn't? What if there's a loophole?
<v Speaker 3>Ah? That is the question, and that is the question
<v Speaker 3>that sent a team of physicists deep deep underground in
<v Speaker 3>Italy to try and catch the universe cheating at its
<v Speaker 3>own game.
<v Speaker 2>And that's what we're digging into today. We are looking
<v Speaker 2>at a report from fizzdot org dated February five, twenty
<v Speaker 2>twenty six, which covers this massive, high stakes study. It
<v Speaker 2>was published in Scientific Reports a few months prior, back
<v Speaker 2>in November twenty twenty five.
<v Speaker 3>It's all about the VIP two experiment.
<v Speaker 2>The IP two. This is the absolute cutting edge of
<v Speaker 2>foundational physics, it really is. And their mission was simple,
<v Speaker 2>but I mean incredibly audacious. Break the poly exclusion principle,
<v Speaker 2>find a crack in the foundation, and what.
<v Speaker 3>They found, or maybe what they didn't find tells us
<v Speaker 3>something just incredible about the nature of our reality.
<v Speaker 2>It's a story about copper, new electrons and a number
<v Speaker 2>so vanishingly small it's hard to even visualize.
<v Speaker 3>So we're going underground.
<v Speaker 2>So let's unpack this. We're going to Grand Sasa, We're
<v Speaker 2>going to the quantum realm, and we're going to find
<v Speaker 2>out why you're not currently sinking through your chair.
<v Speaker 3>Sounds like a plan.
<v Speaker 2>I'm ready, okay, So let's start with the cornerstone, the
<v Speaker 2>rule itself, the poly exclusion principle. Sounds very bureaucratic, doesn't it.
<v Speaker 2>The exclusion principle like a velvet rope at some exclusive club.
<v Speaker 3>That is actually a surprisingly accurate analogy. The principle was
<v Speaker 3>formulated by Wolfgang Polly, an Austrian Swiss physicist, way back
<v Speaker 3>in nineteen twenty five.
<v Speaker 2>Set the scene for us. Nineteen twenty five, what's happening
<v Speaker 2>in physics?
<v Speaker 3>Oh, it was the golden age of quantum mechanics. You
<v Speaker 3>have to understand at this time physicists were in a
<v Speaker 3>state of equal parts panic and excitement.
<v Speaker 2>A good stit to be in for discovery.
<v Speaker 3>The best, the old comfortable rules of Isaac Newton, where
<v Speaker 3>things moved in predictable lines like clockwork. They were just
<v Speaker 3>falling apart. When they looked at Adams, electrons weren't behaving
<v Speaker 3>like little planets orbiting a sun right the old Boar
<v Speaker 3>model exactly. They were jumping around, disappearing and reappearing. It
<v Speaker 3>was just chaos. Nobody could make sense of the data
<v Speaker 3>they were seeing from spectroscopy.
<v Speaker 2>And Polly comes along and acts as the sheriff, lays
<v Speaker 2>down the law.
<v Speaker 3>He essentially does. Polly was known for being incredibly critical,
<v Speaker 3>just famously sharp. People called him the conscience of physics.
<v Speaker 2>The conscience of physics. I love that.
<v Speaker 3>Yeah. If he thought a theory was sloppy or poorly
<v Speaker 3>thought out, he wouldn't just say it was wrong. He
<v Speaker 3>had this famous brutal put down. He'd say, that isn't
<v Speaker 3>even wrong.
<v Speaker 2>Ouch, that's colder than saying it's wrong.
<v Speaker 3>It meant it was so incoherent it wasn't even worth discussing.
<v Speaker 3>He demanded precision, and in nineteen twenty five he proposed
<v Speaker 3>this principle to finally explain the structure of atoms. Why
<v Speaker 3>electrons arraigned themselves the way they did.
<v Speaker 2>So what does the law actually say in simple terms?
<v Speaker 3>Oh, understand it. We first have to understand that in
<v Speaker 3>the quantum world, particles are divided into two main tribes.
<v Speaker 3>You're the bosons and you have the fermions.
<v Speaker 2>Okay, tribes, I like that. What's the difference.
<v Speaker 3>Bosons are the party.
<v Speaker 2>Animals, the social butterflies.
<v Speaker 3>Totally. These are particles like photons, you know, light particles.
<v Speaker 3>The defining characteristic of a boson is that it loves company.
<v Speaker 3>You can pile as many bosons as you want into
<v Speaker 3>the exact same quantum state.
<v Speaker 2>Give visual for that.
<v Speaker 3>Think of a laser beam. In a laser you have
<v Speaker 3>trillions upon trillions of photons, all marching in perfect lockstep.
<v Speaker 3>They overlap, They occupy the same space at the same time,
<v Speaker 3>with the same energy, same direction. They are perfectly happy
<v Speaker 3>to stack right on top of each other.
<v Speaker 2>They don't mind crowds.
<v Speaker 3>They love crowds. They are, in a word.
<v Speaker 2>Social, right, They stack like, I don't know, like thoughts.
<v Speaker 2>You can have a million thoughts in your head at once.
<v Speaker 3>That's a poetic way to put it. Sure, they are
<v Speaker 3>permeable to each other. But then then you have the
<v Speaker 3>fermions and electrons, which are the stars of our story
<v Speaker 3>today are fermions.
<v Speaker 2>And let me guess fermions are not party animals.
<v Speaker 3>They are antisocial, deeply, deeply antisocial. The poly exclusion principle
<v Speaker 3>basically says no two identical fermions can occupy the same
<v Speaker 3>quantum state at the same time period.
<v Speaker 2>This seat is taken precisely.
<v Speaker 3>It's the ultimate one per customer rule. If an electron
<v Speaker 3>is in a certain energy state, you can think of
<v Speaker 3>it like a designated parking spot in a garag. No
<v Speaker 3>other electron in that atom can park there. It is
<v Speaker 3>strictly forbidden.
<v Speaker 2>Now, when you say parking spot or quantum state, we're
<v Speaker 2>talking about more than just location, right, It's a bit
<v Speaker 2>more specific than.
<v Speaker 3>That, right, Yeah, good point. In quantum mechanics, a state
<v Speaker 3>is defined by a set of numbers. We call them
<v Speaker 3>quantum numbers. It's like a unique address. You have the
<v Speaker 3>energy level, the angular momentum, the magnetic moment and critically
<v Speaker 3>the spin spin up or spin down exactly. So Pauli's
<v Speaker 3>rule says you cannot have two electrons in the same
<v Speaker 3>atom with the exact same list of numbers. You could
<v Speaker 3>have two in the same energy level, but one must
<v Speaker 3>be spin up and the other must be spinned down.
<v Speaker 3>Once both those spots are taken, that level is full.
<v Speaker 2>So if I'm an electron and I want to join
<v Speaker 2>an atom, I'm naturally drawn to the lowest energy spot,
<v Speaker 2>the best parking spot, right near the interest.
<v Speaker 3>That's where you want to go, less energy expended.
<v Speaker 2>But if there's already an electron there with spin up
<v Speaker 2>and another with spin down, that level is completely full.
<v Speaker 3>You cannot enter. You are physically barred from that state.
<v Speaker 3>To or says no, you have to go to the
<v Speaker 3>next level up, and if that's full, the next one
<v Speaker 3>and the next one after that.
<v Speaker 2>This sounds like a real hassle for the electrons.
<v Speaker 3>It is. They want to be in the lowest energy
<v Speaker 3>state possible. They want to relax down in the basement,
<v Speaker 3>but the exclusion principle forces them to stack up one
<v Speaker 3>by one into these layers or shells around the.
<v Speaker 2>Nucleus, and the stacking, this fourcelayering. This is the key
<v Speaker 2>to everything, isn't it.
<v Speaker 3>It is the key to the entire universes. We know
<v Speaker 3>it because if they could all just crash down into
<v Speaker 3>that bottom level, if they could all pile up.
<v Speaker 2>Like bosons, what had happened, what would an atom look like.
<v Speaker 3>You wouldn't have chemistry at all. Think about the periodic table.
<v Speaker 3>The entire reason carbon behaves differently than oxygen, which behaves
<v Speaker 3>differently from iron, is entirely because they have different numbers
<v Speaker 3>of electrons arranged in different shells. Because of this exclusion rule.
<v Speaker 2>Ah.
<v Speaker 3>Of course, carbon has four electrons in its outer shell,
<v Speaker 3>so it wants to form four bonds. It's the basis
<v Speaker 3>of all organic life. Oxygen has six in its outer shell,
<v Speaker 3>so it behaves in a completely different way. If they
<v Speaker 3>all just piled into the basement, every atom would just
<v Speaker 3>be a slightly heavier, slightly more negative version of hydrogen.
<v Speaker 3>They'd all behave roughly the same.
<v Speaker 2>So there'd be no complex bonds, no molecules.
<v Speaker 3>No DNA, no proteins, no water, no life. You and
<v Speaker 3>I would not be having this conversation. Chemistry is basically
<v Speaker 3>just the consequence of electrons dealing with the lack of
<v Speaker 3>parking spaces.
<v Speaker 2>That is a fantastic way to think about it. Chemistry
<v Speaker 2>is the result of overcrowding.
<v Speaker 3>It is, and it goes beyond just chemistry. This rule
<v Speaker 3>is what creates the rigidity of matter. Thus solidity.
<v Speaker 2>Tay back to the table I'm touching right.
<v Speaker 3>Now, exactly when you press your hand against the table.
<v Speaker 3>What's actually happening. The electrons in the atoms of your
<v Speaker 3>hand are pushing against the electrons in the atoms of
<v Speaker 3>the table. They literally cannot occupy the same space.
<v Speaker 2>So the feeling of solid.
<v Speaker 3>That resistance, you feel, that solidness isn't the physical matter
<v Speaker 3>of your hand touching the physical matter of the table.
<v Speaker 3>That's not what's ha happening.
<v Speaker 2>What is it?
<v Speaker 3>Then? It is the poly exclusion principle in action. It
<v Speaker 3>is a quantum force. We call it a degeneracy pressure
<v Speaker 3>that is screaming back off. This space is taken at
<v Speaker 3>an atomic level.
<v Speaker 2>That is wild. I'm not feeling wood, I'm feeling a
<v Speaker 2>quantum law.
<v Speaker 3>You are feeling the fundamental architecture of the universe refusing
<v Speaker 3>to collapse on itself.
<v Speaker 2>And this scales up, doesn't it. I mean, this isn't
<v Speaker 2>just for desks. The source material mentions stars.
<v Speaker 3>Oh, it scales up in a huge way. Look at
<v Speaker 3>white dwarf stars. These are the dead, collapsed cores of
<v Speaker 3>stars like our sun. They are incredibly dense. We're talking
<v Speaker 3>about the mass of the Sun packed into a sphere
<v Speaker 3>the size of the Earth.
<v Speaker 2>And gravity is trying to crush them even further into
<v Speaker 2>a single point.
<v Speaker 3>Yes, gravity is relentless, it's pulling everything inward. But the
<v Speaker 3>star stops collapsing at that certain size. Why because the
<v Speaker 3>electrons inside are packed so incredibly tight that the exclusion
<v Speaker 3>principle kicks in. On a macroscopic scale, the parking garage
<v Speaker 3>is full. The parking garage is full on a stack.
<v Speaker 3>The electrons are screaming. We cannot get any closer. That
<v Speaker 3>outward pressure, that absolute refusal to occupy the same state
<v Speaker 3>holds the entire star up against the crushing weight of
<v Speaker 3>its own gravity.
<v Speaker 2>So from the table in my kitchen to a dead
<v Speaker 2>star in deep space, this one simple rule is the
<v Speaker 2>structural engineer keeping everything from imploding.
<v Speaker 3>It is the load bearing wall of the universe. Without it,
<v Speaker 3>the universe would be a soup, a very small, very hot,
<v Speaker 3>very dense soup.
<v Speaker 2>Which makes the source material for this deep dive so
<v Speaker 2>well terrifying. Because we have this quote from Catalina Curciano,
<v Speaker 2>a physicist from the Italian National Institute for Nuclear Physics
<v Speaker 2>the i NFN. She's the spokesperson for this VIP two experiment.
<v Speaker 3>Yes, I remember this quote. It's a very stark warning.
<v Speaker 2>She said. Quote. If the poly exclusion principle were violated,
<v Speaker 2>even at an extremely small level, the consequences would cascade
<v Speaker 2>from atomic physics all the way to astrophysics.
<v Speaker 3>It's a domino effect. If the rule is even slightly squishy,
<v Speaker 3>if an electron can just occasionally sneak into an occupied seat,
<v Speaker 3>then all of matter as we know it is fundamentally unstable.
<v Speaker 2>The domino's fault, all.
<v Speaker 3>Of them all at once.
<v Speaker 2>So naturally, knowing that the fate of the entire universe
<v Speaker 2>rests on this one single rule, scientists decided, Hey, let's
<v Speaker 2>try to break it.
<v Speaker 3>Well, that is the scientific way, isn't it. You don't trust,
<v Speaker 3>you verify, And the most rigorous way to verify something
<v Speaker 3>is to try your absolute hardest to destroy it.
<v Speaker 2>But seriously, let's play Devil's advocate for a minute. If
<v Speaker 2>this rule is so perfect, if it's the only thing
<v Speaker 2>keeping us solid and stable, why are we spending millions
<v Speaker 2>of dollars in years of time trying to prove it wrong.
<v Speaker 2>Why poke the bear?
<v Speaker 3>It's the itch, It's the fundamental scientific itch. We have
<v Speaker 3>this incredibly successful theory called the Standard Model of particle physics, right.
<v Speaker 2>Our best description of well, almost everything exactly.
<v Speaker 3>It predicts the behavior of particles with just insane accuracy.
<v Speaker 3>It is the most successful scientific theory in human history,
<v Speaker 3>and built into its very foundation is the assumption that
<v Speaker 3>the poly exclusion principle is exact perfect, zero exception.
<v Speaker 2>There's always a butt.
<v Speaker 3>But we know the Standard Model isn't the final word.
<v Speaker 3>It's beautiful, but it's flawed. It has holes. It doesn't
<v Speaker 3>explain everything we see in the universe.
<v Speaker 2>Like what what are the big holes?
<v Speaker 3>Well, it has nothing to say about dark matter, which
<v Speaker 3>we think makes up about twenty five percent of the universe.
<v Speaker 3>It has no explanation for dark energy, which is causing
<v Speaker 3>the expansion of the universe to accelerate. And the biggest
<v Speaker 3>one of all, it doesn't include gravity.
<v Speaker 2>It's like having a perfect map of the world that's
<v Speaker 2>missing an entire continent exactly.
<v Speaker 3>We know there is new physics out there, but deeper theory,
<v Speaker 3>we just don't know where to find it. So physicists
<v Speaker 3>are like detectives looking for cracks in the Standard Model.
<v Speaker 3>They're looking for any place where the rules bend, even
<v Speaker 3>just a little bit, and.
<v Speaker 2>That's what they mean by exotic physics, right, And what was.
<v Speaker 3>The most fundamental place is to look for a crack
<v Speaker 3>is right at the foundation? What if the exclusion principle
<v Speaker 3>isn't a hard absolute no, but more of a mostly no,
<v Speaker 3>like a no.
<v Speaker 2>But maybe if you're really really quick and nobody is looking,
<v Speaker 2>sort of rule exactly.
<v Speaker 3>And there are actual theoretical models. These are speculative, but
<v Speaker 3>they're out there, things called Quan models that play with
<v Speaker 3>this idea quon as in q yes. In standard physics,
<v Speaker 3>a particle is either a fermion, which is antisocial, or
<v Speaker 3>a boson, which is social. It's binary, it's one or
<v Speaker 3>the other, flagger white. But Quan models speculate what if
<v Speaker 3>there's a spectrum. What if a particle could be, say,
<v Speaker 3>ninety nine point nine percent fermion, but have a tiny
<v Speaker 3>tiny bit of boson character mixed in.
<v Speaker 2>It could occasionally cheat the system.
<v Speaker 3>It could occasionally cheat. It creates a loophole, a slight violation,
<v Speaker 3>and if that happens, even incredibly rarely, it would be
<v Speaker 3>a huge clue to a deeper level of reality. Atels
<v Speaker 3>that are neat categories of fermion and boson are just
<v Speaker 3>approximations of something much more complex and interesting.
<v Speaker 2>And the source. It also mentions another possibility this could
<v Speaker 2>point to, which is the structure of the electron itself.
<v Speaker 2>This really blew my mind. We usually think of electrons
<v Speaker 2>as just dots, little points of charge.
<v Speaker 3>Correct in the standard model, electrons are fundamental particles. They
<v Speaker 3>have zero size. They are just a point of charge
<v Speaker 3>in mass. You can't cut an electron in half.
<v Speaker 2>But if the exclusion principle can be violated, that might
<v Speaker 2>change our view of that.
<v Speaker 3>It could imply that electrons aren't fundamental at all, that
<v Speaker 3>they might have an internal structure, that they are made
<v Speaker 3>of even smaller things.
<v Speaker 2>Like little gears inside or components, or that they are squishy.
<v Speaker 3>Think about it this way. If two perfectly rigid billiard
<v Speaker 3>balls hit each other, they bounce off they cannot occupy
<v Speaker 3>the same space. But if two tennis balls hit each
<v Speaker 3>other hard enough they can press they deform for a moment.
<v Speaker 2>So if electrons have internal parts, maybe under extreme pressure
<v Speaker 2>they can. They can deform slightly and squeeze into a
<v Speaker 2>state where a perfectly rigid point particle couldn't fit.
<v Speaker 3>That's the idea exactly. So if we find a violation
<v Speaker 3>of poly. It's a very strong hint that the electron
<v Speaker 3>isn't a simple dot, but a complex object with moving parts.
<v Speaker 2>And then there's a big one, the one everyone's chasing,
<v Speaker 2>quantum gravity.
<v Speaker 3>The holy grail of modern physics.
<v Speaker 2>We are desperately, desperately trying to merge Einstein's general relativity,
<v Speaker 2>which governs gravity and big stuff like planets and galaxies,
<v Speaker 2>with quantum mechanics, which governs the small stuff like atoms
<v Speaker 2>and particles.
<v Speaker 3>And they hate each other. They just they do not
<v Speaker 3>get along mathematically. They speak different languages.
<v Speaker 2>But some of the theories that are trying to build
<v Speaker 2>that bridge, like certain versions of string theory or quantum
<v Speaker 2>loot gravity, they actually predict that the poly exclusion principle
<v Speaker 2>might have tiny, tiny cracks, right.
<v Speaker 3>Yes, some of them do. Some theories suggest that space
<v Speaker 3>time itself might not be a smooth, continuous fabric. It
<v Speaker 3>might be fuzzy or discrete, like it's made of pixels
<v Speaker 3>at the smallest possible scales, the Plank scale, right, And
<v Speaker 3>if space is bumpy at that level, it might mess
<v Speaker 3>with the strict rules of quantum mechanics. It might cause
<v Speaker 3>an electron to slip or tunnel into a forbidden state
<v Speaker 3>every once in a while.
<v Speaker 2>So finding a violation would be like finding a loose thread.
<v Speaker 2>You pull on it and the whole standard model unravels,
<v Speaker 2>But underneath you might find the real fabric of the universe.
<v Speaker 3>That is the hope. That is why they search. Finding
<v Speaker 3>a violation wouldn't be a disaster for science. It would
<v Speaker 3>be the greatest discovery of the century. It would be
<v Speaker 3>the signpost pointing the way to the theory of everything.
<v Speaker 2>So the stakes are just incredibly high. Either we confirm
<v Speaker 2>the stability of reality as we know it, or we
<v Speaker 2>find a portal to a whole new level of physics,
<v Speaker 2>which brings us to the experiment. How do you actually
<v Speaker 2>test this? How do you catch an electron cheating?
<v Speaker 3>This is the VIP two experiment. VIP stands for violation
<v Speaker 3>of the poly principle.
<v Speaker 2>And I love the sitting. This isn't happening in a
<v Speaker 2>shiny lab in a university basement. This is deep.
<v Speaker 3>Underground Grandsasso National Laboratory. Yeah, it's really an amazing place,
<v Speaker 3>a series of massive experimental halls that have been hollowed
<v Speaker 3>out from inside a mountain in Italy. You have to
<v Speaker 3>drive through a long highway tunnel to even get to
<v Speaker 3>the entrance.
<v Speaker 2>Why hide under a mountain. Are they hiding from the electrons?
<v Speaker 3>No, they're hiding from noise. We are right now constantly
<v Speaker 3>being bombarded by cosmic rays. These are high energy particles,
<v Speaker 3>mostly protons, flying in from space from supernovas and distant galaxies.
<v Speaker 2>And they're hitting our atmosphere.
<v Speaker 3>They hit the atmosphere and create a shower of secondary particles,
<v Speaker 3>and some of those particles, especially the ones called muons,
<v Speaker 3>make it all the way down to the surface. Billions
<v Speaker 3>of them are passing through your body as we speak. Well,
<v Speaker 3>that's comforting. It's totally harmless to us. But if you're
<v Speaker 3>running an experiment that is as sensitive as VIP two,
<v Speaker 3>a single cosmic ray hitting your detector would be a
<v Speaker 3>disaster because it would create a flash of energy signal
<v Speaker 3>that could look just like the violation you're hunting for.
<v Speaker 3>It would be like trying to listen for a pin
<v Speaker 3>drop in the middle of a thunderstorm.
<v Speaker 2>So the mountain acts as a giant umbrella.
<v Speaker 3>Giant rock umbrella. It's over a kilometer of solid rock
<v Speaker 3>overhead that blocks out almost all of the cosmic noise.
<v Speaker 3>Creating one of the quietest places on Earth in terms
<v Speaker 3>of radiation.
<v Speaker 2>Okay, got it, So silence, darkness, a mile of rock overhead,
<v Speaker 2>and in the middle of this cavern they have the
<v Speaker 2>VIP two apparatus. What are they actually pointing their detectors at.
<v Speaker 3>A chunk of copper.
<v Speaker 2>Copper are just just.
<v Speaker 3>Like copper wire, a strip of high purity copper conductor.
<v Speaker 3>Copper is a great choice because it's atomic structure is very,
<v Speaker 3>very well understood. We know exactly where the electrons should be,
<v Speaker 3>we know their parking spots.
<v Speaker 2>And they are looking for something called forbidden transitions. We
<v Speaker 2>touched on this, but walk me through exactly what that
<v Speaker 2>looks like in the experiment.
<v Speaker 3>Okay, so imagine the copper atom is like that parking
<v Speaker 3>garage we talked about. All the lower levels, what physicists
<v Speaker 3>call the k shell the lshll are full. They are
<v Speaker 3>packed tight with electrons.
<v Speaker 2>The VIP section is totally booked.
<v Speaker 3>Yes, the experimenters are watching to see if an electron
<v Speaker 3>suddenly jumps from a high outer level down to one
<v Speaker 3>of those lower levels that is already.
<v Speaker 2>Occupied, the move that Paully says is completely illegal.
<v Speaker 3>The forbidden move. Now in physics, energy is never lost,
<v Speaker 3>it just changes form. When an electron drops from a
<v Speaker 3>high energy state to a low energy state, it has
<v Speaker 3>to get rid of that excess energy. Usually this energy
<v Speaker 3>comes out as a photon, a particle of light. Okay,
<v Speaker 3>so a flash of light, a flash of light. And
<v Speaker 3>if an electron were to crash the party and drop
<v Speaker 3>into an already occupied slot, the energy difference between those
<v Speaker 3>two levels is very specific. It's a known quantity. It
<v Speaker 3>would release that energy as an X.
<v Speaker 2>Ray, an X ray, not visible light, an X.
<v Speaker 3>Ray because the energy drop is quite large, but not
<v Speaker 3>just any X ray, because the energy levels are shifted
<v Speaker 3>just slightly by the presence of the other electrons what's
<v Speaker 3>called a shielding effect. It would be an X ray
<v Speaker 3>at a very specific, predictable energy level, a specific color
<v Speaker 3>of X ray, if.
<v Speaker 2>You will, and that color should not exist in nature.
<v Speaker 3>Physic says that transition is impossible, so that specific X
<v Speaker 3>ray should never ever be emitted by a copper atom.
<v Speaker 2>So they're basically looking for a very specific flash of
<v Speaker 2>X ray light that would be the smoking gun of
<v Speaker 2>a rule violation. It's like looking for a neon green swan.
<v Speaker 2>If you see one, you know the laws of biology
<v Speaker 2>as we understand them are broken.
<v Speaker 3>Precisely. It's an unambiguous signal. But here is the really
<v Speaker 3>clever part of the VIP two experiment, and this is
<v Speaker 3>a detail that Alessio Procelli, the late author, really emphasized
<v Speaker 3>in the report. You can't just stare at a block
<v Speaker 3>of copper and wait.
<v Speaker 2>Why not. The electrons are already in there, they're whizzing around.
<v Speaker 2>One of them might cheat.
<v Speaker 3>Because of a subtle but very important rule in quantum mechanics,
<v Speaker 3>violations of this type are effectively forbidden from appearing in
<v Speaker 3>what we call a closed system.
<v Speaker 2>A closed system, if you just have.
<v Speaker 3>A block of copper sitting there, the electrons have already
<v Speaker 3>settled into their states, they've established their pecking order, they
<v Speaker 3>are in a stable configuration. They obey something called the
<v Speaker 3>Messiah Greenberg super selection rule, which basically says, if you
<v Speaker 3>start with a system of pure fermions, it's going to
<v Speaker 3>stay a system of pure fermions.
<v Speaker 2>So it's like staring at a perfectly parked car and
<v Speaker 2>waiting for it to double park. It's already parked.
<v Speaker 3>It's done exactly. To catch a violation, you need to
<v Speaker 3>introduce fresh players you need to create an open system.
<v Speaker 3>You need to probe the atoms with something new.
<v Speaker 2>An open system. How do they open it up?
<v Speaker 3>This is the genius of the experiment. Borcelli explains that
<v Speaker 3>they injected a huge number of new electrons into the
<v Speaker 3>copper target.
<v Speaker 2>How do you just inject electrons into a piece of metal.
<v Speaker 3>Simple brute force. They run a DC current through it,
<v Speaker 3>a very very strong electrical current.
<v Speaker 2>How strong are we talking about?
<v Speaker 3>One hundred amps?
<v Speaker 2>Whoa one hundred amps? That's a lot of juice. That's
<v Speaker 2>not your phone charger. That's like industrial welding level current.
<v Speaker 3>It is a massive amount of current. They had to
<v Speaker 3>have integrated cooling systems built into the apparatus just to
<v Speaker 3>keep the copper strip from melting. But think about what
<v Speaker 3>a current actually is. It's a river of electrons. By
<v Speaker 3>running that current, they are forcing billions upon billions of
<v Speaker 3>new electrons to flow into the copper atoms every single second.
<v Speaker 2>Uh okay, I see it now. So the current is
<v Speaker 2>basically a constant river of strangers flowing into the parking garage.
<v Speaker 3>Yes, and these new electrons they haven't established a relationship
<v Speaker 3>with the copper atoms yet. They are naive they come
<v Speaker 3>zooming in looking for a spot to land or just
<v Speaker 3>a path to pass through. This is the moment of truth.
<v Speaker 2>This is the real test.
<v Speaker 3>As these new electrons interact with the atoms, will they
<v Speaker 3>all follow the rules and stay out of the occupied
<v Speaker 3>lower levels, or will one of these fresh naive electrons
<v Speaker 3>try to slip into an occupied seat in the basement.
<v Speaker 2>That makes so much sense. You're not just watching, You're
<v Speaker 2>actively stressing the system. You're throwing millions of new cars
<v Speaker 2>into the lot every second to see if chaos breaks out.
<v Speaker 3>It creates what they call a clean and decisive test.
<v Speaker 3>It dramatically increases the probability of catching a violation if
<v Speaker 3>one exists. It turns a static painting into a chaotic movie.
<v Speaker 2>So they have the mountain shield, they have the copper target,
<v Speaker 2>they have the one hundred amp current pumping in fresh electrons,
<v Speaker 2>and they have these ultralow noise X ray detectors watching
<v Speaker 2>like hawks. What kind of detectors are these?
<v Speaker 3>They're called silicon drift detectors. They are extremely precise, a
<v Speaker 3>type of CCD, and they are cool to incredibly low
<v Speaker 3>temperatures to reduce any thermal noise. They need to be
<v Speaker 3>able to distinguish a single forbidden X ray photon from
<v Speaker 3>any other background radiation that might get through the shielding.
<v Speaker 2>And how long did they run this? This doesn't sound
<v Speaker 2>like a weekend project.
<v Speaker 3>Several years they monitored this target, collecting data, continuously filtering
<v Speaker 3>out background noise, calibrating, recalibrating, just waiting, waiting for that
<v Speaker 3>one specific X ray blip that would change the world.
<v Speaker 2>The patients involved. Is just staggering. The tension must have
<v Speaker 2>been incredible. I mean, every single time they checked the data,
<v Speaker 2>they could have been on the verge of rewriting all
<v Speaker 2>of physics.
<v Speaker 3>Or confirming that everything is exactly as boring and stable
<v Speaker 3>as we thought. That is the life of an experimental physicist.
<v Speaker 3>Ninety nine percent boredom, one percent sheer, terror or elation.
<v Speaker 2>Now the drum roll, please, After years under a mountain
<v Speaker 2>watching a supercharge piece of copper, what did they find?
<v Speaker 3>Nothing? Silence, No such signals were observed. That's the line
<v Speaker 3>from the paper.
<v Speaker 2>Not a single one out of all those billions upon
<v Speaker 2>billions of electrons flowing through one hundred amps per years, not.
<v Speaker 3>A single forbidden transition was detected.
<v Speaker 2>Now to a regular person, that sounds like a failure.
<v Speaker 2>We spent years and millions of dollars looking for a
<v Speaker 2>ghost and we didn't find it. But in science, and
<v Speaker 2>especially in this kind of science, a null result is
<v Speaker 2>a huge deal.
<v Speaker 3>Right, It is massive. In fact, in precision physics, a
<v Speaker 3>null result is often more powerful and more important than
<v Speaker 3>a discovery, because it's not just we found nothing, it's
<v Speaker 3>we look this hard, with this much incredible precision and
<v Speaker 3>found nothing.
<v Speaker 2>It lets them put a number on it.
<v Speaker 3>It allows them to put another number on the probability,
<v Speaker 3>an upper limit the number.
<v Speaker 2>Let's talk about this number, because the article says they
<v Speaker 2>set an upper limit on the probability of violation.
<v Speaker 3>Yes, based on the complete absence of a signal over
<v Speaker 3>the course of the experiment. They concluded that if the
<v Speaker 3>poly exclusion principle is ever violated for electrons, the probability
<v Speaker 3>of it happening is smaller than two parts in ten
<v Speaker 3>to the power of forty three.
<v Speaker 2>Ten to the forty three. Okay, we throw around big
<v Speaker 2>numbers on this show all the time, but I really
<v Speaker 2>need to contextualize that ten to the forty three is
<v Speaker 2>a one followed by forty three zeros.
<v Speaker 3>Correct, It is a number so vast it is effectively
<v Speaker 3>meaningless to the human brain.
<v Speaker 2>I tried to look up some comparisons for this, and honestly,
<v Speaker 2>our normal astronomical numbers don't even cut it. The universe
<v Speaker 2>is about thirteen point eight billion years old. Do you
<v Speaker 2>know how many seconds that is?
<v Speaker 3>It's roughly four times ten to the seventeen seconds.
<v Speaker 2>Okay, so ten to the seventeen we are talking about
<v Speaker 2>ten to the forty three. That is, that's twenty six
<v Speaker 2>orders of magnitude larger. That's a trillion, trillion times longer
<v Speaker 2>than the age of the universe.
<v Speaker 3>It dwarfs the number of atoms in the Earth. It
<v Speaker 3>dwarfs the number of stars in the observable universe. It's
<v Speaker 3>a different class of number. If you ran this experiment
<v Speaker 3>once every second for the entire history of the universe
<v Speaker 3>since the Big Bang, you still wouldn't be anywhere close
<v Speaker 3>to hitting ten to the forty three trials.
<v Speaker 2>So when they say the probability is less than two
<v Speaker 2>in ten to the forty three, they are saying that
<v Speaker 2>the poly exclusion principle is really, really, really correct.
<v Speaker 3>It is aggressively correct. This is the strongest experimental constraint
<v Speaker 3>ever achieved for electrons and open systems. It basically says
<v Speaker 3>that if violations happen, they are so mind bogglingly rare
<v Speaker 3>that they might as well not exist for all practical purposes.
<v Speaker 2>It's like saying I'm ninety nine point ninety ninety nine,
<v Speaker 2>and then you just keep saying nine for another forty
<v Speaker 2>digits of percent. Sure of this wall of solid exactly.
<v Speaker 3>It means the note parking sign in the atomic garage
<v Speaker 3>isn't just a suggestion written on cardboard. It is a
<v Speaker 3>law enforced with an iron fie. The universe does not
<v Speaker 3>tolerate cheaters.
<v Speaker 2>So the headline is physicists fail to break fundamental law
<v Speaker 2>of the universe. But the fallout what this result means
<v Speaker 2>for the world of theoretical physics is where the real
<v Speaker 2>drama lies. Because there were people, smart people betting on
<v Speaker 2>those violations.
<v Speaker 3>Oh absolutely, Let's go back to those quand models we
<v Speaker 3>talked about.
<v Speaker 2>Right, the middle ground particles, the ones that are only
<v Speaker 2>kind of fermions.
<v Speaker 3>Christian Pachikiu, who is another leading member of the VIP
<v Speaker 3>two collaboration, was pretty blunt about this in the report.
<v Speaker 3>He said, and I'm quoting, our result places very stringent
<v Speaker 3>constraints on possible deviations strongly restricting the alternative quand models.
<v Speaker 2>Translating that from cautious scientists speak, quans are pretty much dead.
<v Speaker 3>Maybe not completely dead, but they are on life support,
<v Speaker 3>and the family has been called. If you are a
<v Speaker 3>theorist building a model where particles can be partially fermionic,
<v Speaker 3>you now have a massive, massive problem. Your model has
<v Speaker 3>to explain why that partial behavior is completely invisible to
<v Speaker 3>the tune of one in ten to the forty three.
<v Speaker 2>You have to fine tune your theory so precisely that
<v Speaker 2>it almost becomes absurd just to hide from this experiment.
<v Speaker 3>Right. It forces those theories into a box so small
<v Speaker 3>they can barely breathe. It's Okham's razor swinging like a guillotine.
<v Speaker 3>The simplest explanation that electrons are pure, one hundred percent
<v Speaker 3>antisocial fermions is winning by a landslide.
<v Speaker 2>It's like telling a storytelling. Okay, you can write a
<v Speaker 2>fantasy novel, but you can't use magic, dragons, elves, or swords.
<v Speaker 2>Eventually you just run out of room to tell that story.
<v Speaker 3>That's a great analogy, and it's the same thing for
<v Speaker 3>that hidden structure idea.
<v Speaker 2>We talked about the squishy electrons made of smaller parts.
<v Speaker 3>Right, if electrons had internal gears or were made of
<v Speaker 3>subparticles with some theories called preons, we would expect some give.
<v Speaker 3>We would accept that occasionally those internal parts would arrange
<v Speaker 3>themselves in just the right way to allow violation, a
<v Speaker 3>bit of wiggle room exactly. The profound silence from the
<v Speaker 3>VIP two experiment suggests that electrons are incredibly simple, incredibly rigid.
<v Speaker 2>They really are just points, no gears, no fluff, just
<v Speaker 2>a perfect indivisible dot of negative charge.
<v Speaker 3>It seems that way. This result is a huge victory
<v Speaker 3>for the boring but incredibly effective standard model. It reinforces
<v Speaker 3>the idea that elementary particles are truly elementary. They aren't
<v Speaker 3>legos made of smaller legos. They are the smallest, most
<v Speaker 3>fundamental brick.
<v Speaker 2>And this has to ripple out to the search for
<v Speaker 2>quantum gravity too.
<v Speaker 3>The holy grail. Yes, there are all.
<v Speaker 2>These theories of quantum gravity that predict spacetime itself might
<v Speaker 2>be a little fuzzy or discreete and that this fuzziness
<v Speaker 2>might jostle an electron and make it violate the exclusion principle.
<v Speaker 3>Like driving on a really bumpy road might make you
<v Speaker 3>swerve out of your lane every now and then.
<v Speaker 2>That's a perfect analogy. If space time is bumpy, as
<v Speaker 2>predicted by quantum gravity, the electron might swerve and violate Polly.
<v Speaker 2>But VIP two shows the electron stays in its lane
<v Speaker 2>with absolute near perfect precision.
<v Speaker 3>So that tells us that the road space time must
<v Speaker 3>be incredibly smooth. Or if it is bumpy, the bumps
<v Speaker 3>are so ridiculously small they don't affect the electron at all,
<v Speaker 3>which brings us back to what Catalina Cercian who said,
<v Speaker 3>any viable extension of quantum theory must reproduce the Paule
<v Speaker 3>exclusion principle with extraordinary precision.
<v Speaker 2>It's become a gatekeeper. If you have a cool new
<v Speaker 2>theory about the universe, a new theory of everything, you
<v Speaker 2>have to bring it to the VIP two team. And
<v Speaker 2>if your theory predicts a violation rate that is bigger
<v Speaker 2>than one in ten to the forty three, they just
<v Speaker 2>shake their heads and say nope. Back to the drawing board.
<v Speaker 3>Try again, exactly. It clears the board. It sweeps away
<v Speaker 3>a lot of speculative clutter and tells theorists the answer
<v Speaker 3>you're looking for isn't here look elsewhere. It saves us
<v Speaker 3>from wasting decades of brain power on what are now
<v Speaker 3>dead ends.
<v Speaker 2>I want to pivot for a second to something a
<v Speaker 2>bit more philosophical. Here we're talking about precision. We're talking
<v Speaker 2>about measuring nothing to an impossible, almost divine degree.
<v Speaker 3>It is the philosophy of precision.
<v Speaker 2>Yeah, And the article mentions that this research gets support
<v Speaker 2>from the FQXi, the Foundational Questions Institute. They love funding
<v Speaker 2>this kind of deep fundamental stuff.
<v Speaker 3>If you do, they fund the deep, weird questions, the
<v Speaker 3>high risk, high reward science that might not have an
<v Speaker 3>immediate practical application but could change how we see everything.
<v Speaker 2>So why does precision matter so much? Why is it
<v Speaker 2>worth years of a physicist's life and millions of euros
<v Speaker 2>just to add a few more decimal places to a zero.
<v Speaker 2>Why not just say Okay, it works really well and move.
<v Speaker 3>On, because precision is where the new physics hides. Think
<v Speaker 3>about how we discovered general relativity. It wasn't because Newton's
<v Speaker 3>laws of gravity were completely wrong. Newton was great. His
<v Speaker 3>laws get us to the moon.
<v Speaker 2>They worked just fine for most things.
<v Speaker 3>But the orbit of the planet Mercury was off off
<v Speaker 3>by a tiny, tiny fraction of degree per century, a
<v Speaker 3>wobble in its orbit that Newton's theory just could.
<v Speaker 2>Not explain, and most people would just ignore that.
<v Speaker 3>They did for decades. But by chasing that tiny wobble,
<v Speaker 3>that tiny imperfection, Einstein revolutionized our entire understanding of gravity, space,
<v Speaker 3>and time. He realized Newton wasn't wrong, he was just incomplete.
<v Speaker 3>The VIP two team is looking for the wobble in
<v Speaker 3>the poly principle.
<v Speaker 2>And so far absolutely no wobble.
<v Speaker 3>Not a hint of a wobble, which brings us to
<v Speaker 3>what you could call the joy of nothing.
<v Speaker 2>The joy of nothing. I like that.
<v Speaker 3>There's a real comfort in this result.
<v Speaker 2>I feel it, I genuinely do. Knowing that the ground
<v Speaker 2>isn't going to suddenly turn to liquid and swallow me up,
<v Speaker 2>Knowing that chemistry is stable, it's nice to know the
<v Speaker 2>universe isn't glitchy.
<v Speaker 3>It implies a deep stability to the laws of nature.
<v Speaker 3>It suggests that the universe isn't just making it up
<v Speaker 3>as it goes along. There's a rigid, reliable structure to reality.
<v Speaker 2>But I also sense the frustration and the result.
<v Speaker 3>Oh absolutely every experimentalist deep down wants to be the
<v Speaker 3>one to find the anomaly. They want to find the
<v Speaker 3>crack in the wall. The fact that the wall held
<v Speaker 3>up is incredibly impressive, but it's also a door slamming
<v Speaker 3>shut in your face. We wanted to see what was
<v Speaker 3>on the other side.
<v Speaker 2>Sorry, the universe is perfect. Go home laughs.
<v Speaker 3>Essentially, yes, but that doesn't mean you go home. It
<v Speaker 3>just means you have to build a bigger hammer to
<v Speaker 3>hit the wall with next time.
<v Speaker 2>And they are, aren't they. The article clearly mentions the sequel,
<v Speaker 2>VIP three, because VIP two wasn't precise enough.
<v Speaker 3>I ever enough. The team is already planning the next
<v Speaker 3>generation of the experiment. They want to push the sensitivity
<v Speaker 3>even further.
<v Speaker 2>How do you even get better than ten to the
<v Speaker 2>minus forty three?
<v Speaker 3>Better detectors, silicon drift detectors with even faster timing and
<v Speaker 3>better energy resolution, more shielding, maybe higher currents, different target materials,
<v Speaker 3>longer observation times. It's a game of inches, or I guess,
<v Speaker 3>in this case, a game of femtometers.
<v Speaker 2>What's the goal ten to the minus fifty?
<v Speaker 3>Why not? The ultimate goal is to find the breaking point,
<v Speaker 3>or to prove to an even more ridiculous degree of
<v Speaker 3>certainty that there is no breaking point.
<v Speaker 2>And let's say they never find a violation. Let's say
<v Speaker 2>we get to VIP ten in the year twenty fifty
<v Speaker 2>and we're at ten to the minus one hundred. What
<v Speaker 2>does that tell us?
<v Speaker 3>That might be the most profound result of all. If
<v Speaker 3>the poly exclusion principle is truly absolute, if it is
<v Speaker 3>never ever violated, not even once, in the entire life
<v Speaker 3>span of the universe, it suggests that this rule is
<v Speaker 3>somehow different from other physical laws. How so, it's not
<v Speaker 3>just a description of how things move or interact like
<v Speaker 3>a force. It's more like a geometric necessity of reality.
<v Speaker 3>It would mean the universe is built on a kind
<v Speaker 3>of logic that simply cannot be broken.
<v Speaker 2>It's more like a mathematical truth than a physical law.
<v Speaker 3>Exactly, it's more like two plus two to four. You
<v Speaker 3>can't violate that. Maybe the exclusion principle is just two
<v Speaker 3>plus two oz for matter.
<v Speaker 2>A logic that cannot be broken, that is that is heavy.
<v Speaker 2>It is So, as we wrap up this deep dive,
<v Speaker 2>where does this leave us? What's the big picture?
<v Speaker 3>It leaves us standing on very very solid ground. Literally,
<v Speaker 3>we know that electrons are behaving themselves with a discipline
<v Speaker 3>that is almost unimaginable. We know that the antisocial nature
<v Speaker 3>of fermions is holding strong.
<v Speaker 2>My takeaway from all this is a new found respect
<v Speaker 2>for the humble electron. I usually just think of them
<v Speaker 2>as electricity, you know, just juice flowing through a wire.
<v Speaker 2>But really they are the structural beams of the universe,
<v Speaker 2>and they are incredibly perfectly disciplined. They refuse to sit
<v Speaker 2>in an occupied seat, and that simple refusal is the
<v Speaker 2>only reason I exist to talk about them.
<v Speaker 3>That is a beautiful way to put it. My takeaway
<v Speaker 3>is the sheer audacity of the experiment itself. We are
<v Speaker 3>monkeys who evolved on a small rock orbiting an average star,
<v Speaker 3>and we build a machine inside a mountain to check
<v Speaker 3>the math of the universe to the forty third decimal place.
<v Speaker 3>That is something to be proud of as a species.
<v Speaker 2>It really is. It's the human spirit of inquiry at
<v Speaker 2>its absolute peak.
<v Speaker 3>And we aren't done. VIP three is coming. We will
<v Speaker 3>keep knocking on that door until it either opens or
<v Speaker 3>we realize it's just painted on the wall.
<v Speaker 2>Here's a thought to leave you with. Then we've spent
<v Speaker 2>this whole time talking about how the rules held up,
<v Speaker 2>how the universe didn't glitch. But think about this. We
<v Speaker 2>only know the rules hold up here in our quiet
<v Speaker 2>little corner of the galaxy at relatively low energies in
<v Speaker 2>a block of.
<v Speaker 3>Copper, right under normal conditions, so to speak.
<v Speaker 2>What happens inside a black hole? What happened in the
<v Speaker 2>first nanosecond of the Big Bang? Does the paly principle
<v Speaker 2>still hold up when the universe is being crushed into
<v Speaker 2>a singularity under unimaginable gravity and temperature.
<v Speaker 3>Or does the no parking sign eventually get torn down
<v Speaker 3>by the sheer force.
<v Speaker 2>Of gravity exactly? That's the ultimate question. If gravity gets
<v Speaker 2>strong enough, can it finally force the electrons to give
<v Speaker 2>up their space and fall into the same state.
<v Speaker 3>If the exclusion principle fails at the center of a
<v Speaker 3>black hole, that might be what a singularity is, all.
<v Speaker 2>The matter finally collapsing into the forbidden seats.
<v Speaker 3>Into the forbidden seats.
<v Speaker 2>And that gives me something to think about me too,
<v Speaker 2>Until next time, Stay curious.