Anyon-Trion Discovery Advances Quantum Materials Research

<v Speaker 1>Welcome to the Court 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>It is Monday, February sixteenth, twenty twenty six. And you know,
<v Speaker 2>sometimes you come in on a Monday and look at
<v Speaker 2>the research that's just been published and you see something
<v Speaker 2>that frankly shouldn't exist.
<v Speaker 3>Uh yeah, something that breaks the old textbooks for sure.
<v Speaker 2>It absolutely does. We are doing an analysis today of
<v Speaker 2>a paper that just dropped in Nature. It's a huge collaboration.
<v Speaker 2>We're talking University of Washington, Nim's in Japan, Eth.
<v Speaker 3>Zurich, a real powerhouse group.
<v Speaker 2>It is. The title is a bit of a mouthful,
<v Speaker 2>using light to probe fractional charges in a fractional churn insulator.
<v Speaker 2>But what it really means, if I'm getting this right,
<v Speaker 2>is that scientists have found a way to see pieces
<v Speaker 2>of an electron.
<v Speaker 3>Well, let's be super careful with the language right at
<v Speaker 3>the start. Okay, they haven't taken like a tiny knife
<v Speaker 3>and physically chopped up an electron. That would well, that
<v Speaker 3>would up end the standard model and probably break physics
<v Speaker 3>as we know it.
<v Speaker 2>Right, No knives involved, no knives, But.
<v Speaker 3>We have done something that, for all practical purposes, looks
<v Speaker 3>and acts exactly like that. We've created and then observed
<v Speaker 3>a state of matter where electricity doesn't flow in units
<v Speaker 3>of one electron. It flows in units of say one
<v Speaker 3>third of an.
<v Speaker 2>Electron, which is the very definition of a fractional charge.
<v Speaker 2>Something that just sounds impossible on its face.
<v Speaker 4>It does.
<v Speaker 3>And the big news here, the real headline isn't just
<v Speaker 3>that these things exist. We've had hints of that for decades,
<v Speaker 3>you know, in these massive high magnetic field experiments.
<v Speaker 2>Trying to take up a whole room and need cryo
<v Speaker 2>cooling exactly.
<v Speaker 3>The headline is that this team found a way to
<v Speaker 3>see them, to optically detect them. They just they shone
<v Speaker 3>a light on the material and they could read the
<v Speaker 3>signature of this ghost particle.
<v Speaker 2>The ghost particle. Okay, we need to unpack that and
<v Speaker 2>the lantern they used to see it. But before we
<v Speaker 2>get to the ghost in the lantern, we have to
<v Speaker 2>build the stage right the environment where this can even happen.
<v Speaker 3>We have to build a haunted house.
<v Speaker 2>The haunted house. I like that because this phenomenon doesn't
<v Speaker 2>just happen in a normal copper wire, does it. You
<v Speaker 2>can't just find fractional electrons in the wiring in your walls.
<v Speaker 3>Not at all. No, you need a very specific, meticulously
<v Speaker 3>engineered environment. You need something called a more superlattice.
<v Speaker 2>Okay more that's a term I recognize from like photography
<v Speaker 2>or TV. If you wear a shirt with really fine stripes,
<v Speaker 2>the camera creates this weird, wavy shimmering pattern.
<v Speaker 3>That is precisely what it is. But instead of camera
<v Speaker 3>pixels and shirt threads, we're talking about atoms in.
<v Speaker 4>A crystal on an atomic scale exactly.
<v Speaker 3>The material itself is called twisted bill ayer molybdenum detelluride.
<v Speaker 3>The shorthand is tmote you.
<v Speaker 2>Right, And for people following this space, the first question
<v Speaker 2>might be why not graphene. You know, graphene has been
<v Speaker 2>the wonder material for what twenty years now.
<v Speaker 3>Graphene is amazing, don't get me wrong, but graphene is
<v Speaker 3>what we call a semi metal. It doesn't have a
<v Speaker 3>natural band gap, which limits some of its electronic and
<v Speaker 3>optical properties. This material moliditum. To tell your ide is
<v Speaker 3>a semiconductor, so it.
<v Speaker 2>Has a different set of rules for how its electrons can.
<v Speaker 3>Behave a very different playbook. And the real magic, the
<v Speaker 3>part that makes this whole thing possible, is in the
<v Speaker 3>twisted bill layer part of the name the twist.
<v Speaker 4>The twist.
<v Speaker 3>You take one sheet of this material, which is just
<v Speaker 3>one atom thick. Then you take a second sheet and
<v Speaker 3>you lay it on top. But and this is the key,
<v Speaker 3>you don't line them up perfectly. You twist the top
<v Speaker 3>layer just a tiny, tiny bit. We're talking between three
<v Speaker 3>and four degrees, a very specific small angle, and.
<v Speaker 2>That little twist changes everything.
<v Speaker 3>It changes absolutely everything. When you misalign the atomic grids
<v Speaker 3>of the two layers, this new larger scale pattern emerges.
<v Speaker 3>Just like your screen door analogy, you get these big
<v Speaker 3>repeating hexagonal cells. That new larger pattern is the more superlattice.
<v Speaker 2>So you're not changing the atoms, you're changing the geometry.
<v Speaker 2>You're creating a new landscape for the electrons to live in.
<v Speaker 3>You're creating a new potential energy landscape. And that is
<v Speaker 3>the crucial insight. Think of electrons in a normal metal
<v Speaker 3>like copper. They're like race cars on a perfectly smooth
<v Speaker 3>flat race track. Their kinetic energy is really.
<v Speaker 2>High, so they're just zipping around everywhere.
<v Speaker 3>Zipping around, and they're moving so fast that they mostly
<v Speaker 3>ignore each other. The repulsion between them doesn't have much
<v Speaker 3>effect because their momentum is the dominant factor.
<v Speaker 2>They're too busy moving to interact.
<v Speaker 3>Right, But this more pattern, It's like putting a whole
<v Speaker 3>grid of speed bumps all over the racetrack. It fundamentally
<v Speaker 3>changes the energy structure. It creates what physicists call flat
<v Speaker 3>bands flat bands.
<v Speaker 2>I saw that term all over the paper and sounds counterintuitive.
<v Speaker 2>You'd think flat means they can go faster.
<v Speaker 3>The opposite, a flat energy band means the kinetic energy,
<v Speaker 3>the energy of motion gets quenched. It drops to almost zero.
<v Speaker 3>The electrons basically grind to a halt.
<v Speaker 2>So the race cars are now stuck in a massive traffic.
<v Speaker 3>Jam, a quantum traffic jam. And what happens when you're
<v Speaker 3>suck in traffic You can't ignore the cars around you anymore.
<v Speaker 3>Suddenly the interactions between them become the most important thing.
<v Speaker 2>The cool long interaction, the fact that they're all negatively
<v Speaker 2>charged and they all want to get away from each
<v Speaker 2>other exactly.
<v Speaker 3>That repulsion becomes the dominant force in their universe. They
<v Speaker 3>can't just run away, so they have to organize. They
<v Speaker 3>have to arrange themselves in a very specific collective dance
<v Speaker 3>to minimize their total energy, a coordinated dance, and it
<v Speaker 3>is that collective correlated behavior that gives rise to these
<v Speaker 3>incredible new states of matter. The system as a whole
<v Speaker 3>starts acting in ways that none of the individual electrons.
<v Speaker 2>Could, and that specific state is what they're calling a
<v Speaker 2>fractional churn insulator.
<v Speaker 3>That's the one and each of those words is important.
<v Speaker 3>We have the fractional part, which we'll get to. We
<v Speaker 3>have the insulator part, meaning it doesn't conduct electricity in
<v Speaker 3>a normal way, and then we have the churn part, churn.
<v Speaker 2>That refers to the topology, right it does, so topology.
<v Speaker 2>Most people hear that and think of the coffee mug
<v Speaker 2>and donut analogy. You know, they're the same because they
<v Speaker 2>each have one.
<v Speaker 3>Hole, and that's a perfect starting point. Topology is about
<v Speaker 3>properties that are robust that don't change if you sort
<v Speaker 3>of stretch or bend the system without tearing it. In
<v Speaker 3>this material, the quantum wave functions of the electrons get
<v Speaker 3>twisted into a topologically non trivial knot.
<v Speaker 4>I'm not a mathematical.
<v Speaker 3>Knot, and that intrinsic twist in the system acts like
<v Speaker 3>a built in magnetic field, an incredibly powerful.
<v Speaker 2>One built in so you don't need to put the
<v Speaker 2>sample inside a giant magnet.
<v Speaker 3>And that is the single biggest practical advantage here. That's
<v Speaker 3>the anomalist part of the name. They use the fractional
<v Speaker 3>quantum anomalis Hall effect.
<v Speaker 2>Okay, let's slow down there. The original fractional quantum Hall effect,
<v Speaker 2>the one that won the Nobel Prize. That required massive magnets.
<v Speaker 3>Right massive. We're talking magnetic fields hundreds of thousands of
<v Speaker 3>times stronger than the Earth's. You need huge room size
<v Speaker 3>superconducting magnets to force the electrons into this correlated state.
<v Speaker 2>Which is fantastic for fundamental physics research, but you're never
<v Speaker 2>going to build a computer out of it. You can't
<v Speaker 2>put a twenty tesla magnet in your phone exactly.
<v Speaker 3>It's just not a scalable technology. But in this material,
<v Speaker 3>the more a twist is the magnet. The geometry itself
<v Speaker 3>generates when we call a Barry curvature, which is like
<v Speaker 3>a fictitious internal magnetic field that does all the work
<v Speaker 3>for us.
<v Speaker 2>So you get all the exotic physics of a huge
<v Speaker 2>magnetic field, but it's zero external field.
<v Speaker 1>Zero.
<v Speaker 3>That's the game changer for any future applications.
<v Speaker 2>Okay, so the stage is set. Okay, we have this
<v Speaker 2>twisted bi layer of molybdenum detelluride. The floor is a
<v Speaker 2>grid of quantum speed bumps that slows the electrons down,
<v Speaker 2>forces them to dance together into this topological state. Now
<v Speaker 2>let's bring on the ghost, the Aenian, the Anian. I
<v Speaker 2>have to ask the fundamental question here is an anian?
<v Speaker 2>Is it a real particle or is it just a
<v Speaker 2>useful mathematical fiction. When I hear quasi particle, my brain
<v Speaker 2>immediately translates that to sort of a fake particle.
<v Speaker 3>That's a great question, and it's almost as much a
<v Speaker 3>philosophical one as a physical one. Let me ask you,
<v Speaker 3>this is a wave in the ocean real?
<v Speaker 2>I mean, yeah, if it hits you, you get wet.
<v Speaker 2>The water is real, the energy moving through it is real. Yeah,
<v Speaker 2>so the phenomenon is.
<v Speaker 3>Real exactly, And anion is a quasi particle, which means
<v Speaker 3>it's a collective excitation. It's not a fundamental particle like
<v Speaker 3>an electron or a quark that you'd find in the
<v Speaker 3>standard model. It's an emergent phenomenon. It's the wave, not
<v Speaker 3>the water molecule.
<v Speaker 2>Okay, I can see that it's a disturbance in the
<v Speaker 2>electron soup.
<v Speaker 3>It's a disturbance. But in the quantum world, if it
<v Speaker 3>has well defined properties, if it has a measurable charge,
<v Speaker 3>a measurable mass, if it behaves like a particle, then
<v Speaker 3>for all intents and purposes, it is a particle within
<v Speaker 3>that material, and.
<v Speaker 2>Its properties are just bizarre.
<v Speaker 1>They are.
<v Speaker 3>The charge isn't heminal one like an electron in this state,
<v Speaker 3>it can be ninetag thirteen or negeta twenty three of
<v Speaker 3>the elementary charge.
<v Speaker 2>That just breaks my brain. Everything we learn in school
<v Speaker 2>is that charge is quantized. It comes into multiples of e.
<v Speaker 2>You can have one electron or two or one hundred.
<v Speaker 2>You can't have a third of one.
<v Speaker 3>In free space you can't. But inside this very specific
<v Speaker 3>correlated state of matter you can. It's not a glitch
<v Speaker 3>in the matrix. It's a feature of this unique topological order.
<v Speaker 2>And it's not just the fractional charge. You mentioned something else,
<v Speaker 2>fractional statistics.
<v Speaker 3>What does that mean, this is maybe the weirdest and
<v Speaker 3>most important part in our three D world. All particles
<v Speaker 3>are either fermions like electrons, or bosons like photons. If
<v Speaker 3>you take two identical fermions and swap their positions, the
<v Speaker 3>total quantum wave function gets a minus sign. If you
<v Speaker 3>swap two bosons, nothing changes. It's a binary choice.
<v Speaker 2>Okay, metas one or plus one.
<v Speaker 3>Right, But in two dimensional systems like this material, a
<v Speaker 3>third possibility exists. These quasi particles are aenions because when
<v Speaker 3>you swap two of them, the wave function can pick
<v Speaker 3>up any phase, not just plus one or neck as one.
<v Speaker 4>So like a fraction of a phase exactly.
<v Speaker 3>And this has a profound consequence. Imagine you take one
<v Speaker 3>enion and loop it around another one and bring it
<v Speaker 3>back to where it started. The system remembers that you
<v Speaker 3>did that.
<v Speaker 2>The system keeps a record of their history.
<v Speaker 3>It keeps a record. It's like braiding strands of hair.
<v Speaker 3>If you braid two strands, you've created a permanent topological
<v Speaker 3>link between them. You can't undo it by just jiggling
<v Speaker 3>them locally. That braid is a form of information, and that's.
<v Speaker 2>The topological protection that everyone talks about for quantum computing.
<v Speaker 3>That's the holy grail. A normal quantum bit equivot might
<v Speaker 3>be stored in the spin of a single electron. It's
<v Speaker 3>incredibly fragile. A stray magnetic field, a tiny vibration can
<v Speaker 3>come in and flip the spin, destroying your information.
<v Speaker 2>Decoherence.
<v Speaker 3>Decoherence the mortal enemy of quantum computing. But if your
<v Speaker 3>information is stored in the braid of these anions, in
<v Speaker 3>the topology of their world lines, it's robust. Local noise
<v Speaker 3>can't untie the knot. To destroy the information, you have
<v Speaker 3>to do something catastrophic to the whole system.
<v Speaker 2>So inions of the basis for a fault tolerant quip.
<v Speaker 3>That's the dream. But there's always been this huge practical problem.
<v Speaker 3>Anies are shy. They live deep inside this insulating state,
<v Speaker 3>and an insulator, by its very definition, doesn't conduct electricity well.
<v Speaker 2>So you can't just plug in a multimeter measure them easily.
<v Speaker 3>It's incredibly difficult. The traditional method is called a transport measurement.
<v Speaker 3>You have to physically attach tiny wires or contacts to
<v Speaker 3>a flake of material. It's only two atoms thick. It's invasive,
<v Speaker 3>it can damage the sample, and it usually only tells
<v Speaker 3>you what's happening at the very edge of the material.
<v Speaker 2>It's like trying to figure out what's happening inside a
<v Speaker 2>packed stadium by just looking at who is coming.
<v Speaker 3>In and out of the main gate, a perfect analogy.
<v Speaker 3>You have no idea what's happening in the stands. This
<v Speaker 3>is why this new paper is such a big deal.
<v Speaker 3>The researchers that you UW decided to stop trying to
<v Speaker 3>listen at the door. They decided to find a way
<v Speaker 3>to look through the windows with a flashlight, with a
<v Speaker 3>quantum flashlight.
<v Speaker 2>Okay, so let's talk about the flashlight. This is the tryon,
<v Speaker 2>the tryon. Yes, this part of the paper felt like
<v Speaker 2>a real detective story. They knew the ghost the anion
<v Speaker 2>was in the house, but they needed a way to
<v Speaker 2>see it, so they had to invent a ghost detector.
<v Speaker 2>What exactly is a tryon?
<v Speaker 3>Okay, to get to a try on, you first have
<v Speaker 3>to understand.
<v Speaker 4>And excitement right step by step.
<v Speaker 3>You take your semiconductor material, you shine a laser on it.
<v Speaker 3>A photon from the laser comes in and it has
<v Speaker 3>enough energy to hit an electron and kick it out
<v Speaker 3>of its comfortable home state into a higher energy level.
<v Speaker 2>Okay, it promotes the electron.
<v Speaker 3>It does, and when the electron leaves, it leaves behind
<v Speaker 3>a vacancy, a hole. It's like you standing up from
<v Speaker 3>your chair in a crowded theater. The chair is now empty.
<v Speaker 2>And in semiconductor physics, that hole isn't just nothingness. It
<v Speaker 2>acts like a particle itself.
<v Speaker 3>It acts like a positively charged particle. So now you
<v Speaker 3>have this negatively charged electron that you just picked up
<v Speaker 3>and this positively charged hole that it left behind.
<v Speaker 4>Opposites attract, so they stick together.
<v Speaker 3>They get bound to each other by the electrostatic force,
<v Speaker 3>and they orbit each other. That bound pair the electron
<v Speaker 3>and the hole is an excitant, and because it's a
<v Speaker 3>nice one and a plus one, its total charge is zero.
<v Speaker 3>It's neutral.
<v Speaker 2>Got it. Excitan equals a neutral pair.
<v Speaker 3>Now imagine that neutral excitan is drifting through our material,
<v Speaker 3>through this quantum traffic jam of electrons, and it bumps
<v Speaker 3>into one of the extra free electrons that are just
<v Speaker 3>part of.
<v Speaker 2>The system, and it picks it up like a little
<v Speaker 2>pac men.
<v Speaker 3>It grabs it. The attraction is strong enough to bind
<v Speaker 3>that third particle. So now you have a cluster of
<v Speaker 3>three things two electrons and one hole.
<v Speaker 2>That is a try on two electrons, one hole, so
<v Speaker 2>its net charge is negative.
<v Speaker 3>One precisely unlike the exciting, the trion is a charged particle.
<v Speaker 3>And here's the other crucial piece. Like the exciting, it's optically.
<v Speaker 2>Active, meaning it can absorb and emit light.
<v Speaker 3>Yes, eventually one of the electrons will fall back into
<v Speaker 3>the hole to annihilate it, and when it does, it
<v Speaker 3>releases that energy as a photon of light, a flash.
<v Speaker 3>So what you have in a trian is the perfect spy.
<v Speaker 3>It's a particle that is sensitive to the electric fields
<v Speaker 3>around it because it's charged, and it reports back on
<v Speaker 3>its local environment by emitting light at a very specific
<v Speaker 3>color or frequency.
<v Speaker 2>It's a sensor that glows.
<v Speaker 4>A lantern is the lantern.
<v Speaker 2>So the big idea from the lead researcher, shadlung Shoe
<v Speaker 2>and his group was what if we put these lanterns
<v Speaker 2>into our haunted house. What happens if a tryan meets
<v Speaker 2>an anion.
<v Speaker 3>The central hypothesis was that they would bind together, they'd
<v Speaker 3>stick to each other. Yes, you have the negatively charged
<v Speaker 3>trian and you have the fractionally charged anion, which is
<v Speaker 3>also effectively negative. Now, you'd think two negative things would
<v Speaker 3>just repel each other.
<v Speaker 2>Right, like pushing two magnets together the wrong way.
<v Speaker 3>But because of the complex many body interactions in this
<v Speaker 3>correlated state, the prediction was that they would actually feel
<v Speaker 3>an attractive force. They would form a new composite quasi particle,
<v Speaker 3>an anian tryon, the anyan tryon, a new kind of
<v Speaker 3>fractional charge excitonic state.
<v Speaker 2>That sounds like something straight out of science fiction. But
<v Speaker 2>if this binding happens, what's the evidence? How would you
<v Speaker 2>ever know that they've actually paired up.
<v Speaker 3>In physics, everything wants to find its lowest possible energy state.
<v Speaker 3>It's like a ball wanting to roll downhill. If two
<v Speaker 3>particles can lower their total energy by sticking together, they will.
<v Speaker 3>That missing energy is the binding energy. It's the glue
<v Speaker 3>holding them together.
<v Speaker 2>And energy is related to light.
<v Speaker 3>The color, energy and the frequency of light are directly proportional.
<v Speaker 3>High energy means high frequency, which is bluer light. Low
<v Speaker 3>energy means low frequency, which is redder light.
<v Speaker 2>So if a normal tri in of it's a photon
<v Speaker 2>of a certain color, then a.
<v Speaker 3>Tryon that's bound to an anion which is now in
<v Speaker 3>a lower energy state should emit a photon with less energy.
<v Speaker 3>When it decays, the light it emits should be shifted
<v Speaker 3>towards the red.
<v Speaker 4>End of the spectrum, a red shift.
<v Speaker 3>A red shift. That was the smoking dun they were
<v Speaker 3>looking for. Yeah, a new flash of light at a
<v Speaker 3>new color that only appears when the conditions are perfect
<v Speaker 3>for anians to exist.
<v Speaker 2>Okay, so let's walk through the experiment itself. They build
<v Speaker 2>the device, this twisted bilayer sandwich. What's next.
<v Speaker 3>The next step is incredibly delicate. It's called doping. They
<v Speaker 3>use an electric field applied by a nearby gait electrode
<v Speaker 3>to very carefully add or remove electrons from the material.
<v Speaker 3>They have to tune the electron density with exquisite precision.
<v Speaker 2>It's like tuning an old analog radio dial trying to
<v Speaker 2>find that one feint station.
<v Speaker 3>That is a perfect analogy. You have to turn the
<v Speaker 3>knob just so. If you have too many electrons, the
<v Speaker 3>system just becomes a boring metal. If you have too few,
<v Speaker 3>it's a boring insulator. But if you hit the density
<v Speaker 3>just right at what they call a filling factor of
<v Speaker 3>say negative twenty three.
<v Speaker 2>Meaning for every three spots in the more a lattice
<v Speaker 2>there are two electrons.
<v Speaker 3>Exactly when you hit that magic fraction, the electrons spontaneously
<v Speaker 3>organized into this fractional churn insulator state. The Aenians emerge.
<v Speaker 2>And once they've tuned the dial and the en needs
<v Speaker 2>are there, mm hmm, they turn on the laser.
<v Speaker 3>They turn on the laser. This technique is called photoluminescence spectroscopy.
<v Speaker 3>They shine light of one color in and they use
<v Speaker 3>a very sensitive detector to measure the colors of light
<v Speaker 3>that come back out.
<v Speaker 2>And what do they see on their screen?
<v Speaker 3>They saw a new peak emerge in the spectrum at
<v Speaker 3>filling factors where nothing interesting should be happening. They saw
<v Speaker 3>the expected peaks for regular excitans and trans But as
<v Speaker 3>soon as they tuned the system into that Negavit twenty
<v Speaker 3>three state, a new signal.
<v Speaker 2>Appeared, a new line on the graph, a.
<v Speaker 3>Bright, sharp, new emission line, and it was exactly where
<v Speaker 3>they predicted it would be. It was red shifted. It
<v Speaker 3>was at a lower energy than the normal triand.
<v Speaker 2>So that's the evidence of binding. The energy difference between
<v Speaker 2>the normal try and peak and this new Innian tryon
<v Speaker 2>peak is the glue.
<v Speaker 3>That is the binding energy. But here's the part that
<v Speaker 3>makes it undeniable, the part that rules out other explanations.
<v Speaker 3>The first author on the paper, Ugli, pointed this out.
<v Speaker 3>The amount of the energy shift, the size of the
<v Speaker 3>red shift wasn't random. It scaled directly with the magnitude
<v Speaker 3>of the fractional charge. When they created a state with
<v Speaker 3>menic of thirteen chargeenians, they got one specific red shift.
<v Speaker 3>When they created a state with the menics of twenty
<v Speaker 3>three charge Enians, the red shift was different. It was stronger.
<v Speaker 2>Whoa, So the light itself was carrying the fingerprint of
<v Speaker 2>the fraction It wasn't just telling them something is here,
<v Speaker 2>It was telling them what is here.
<v Speaker 3>They were, in effect optically reading the fractional charge of
<v Speaker 3>the Enian. They were measuring a fundamental property of this
<v Speaker 3>exotic quasi particle without ever touching it with a wire.
<v Speaker 3>It's the first time anyone has done this in one
<v Speaker 3>of these zero field fractional churn insulators.
<v Speaker 2>That's just it's an incredibly elegant piece of physics. It's
<v Speaker 2>like they figured out how to make the ghost glow
<v Speaker 2>in the dark, and the color it glows tells you
<v Speaker 2>exactly what kind of ghost it is.
<v Speaker 3>It is, and it opens up a whole new toolbox.
<v Speaker 3>It builds a bridge between two massive fields of physics
<v Speaker 3>that don't always interact this directly, the world of correlated topology,
<v Speaker 3>which studies these weird collective states, and the world.
<v Speaker 2>Of quantum optics, which studies how light and matter interact
<v Speaker 2>at the single particle level exactly.
<v Speaker 3>Usually, the topology people are over here where they're giant
<v Speaker 3>magnets and dilution refrigerators, and the optics people are over
<v Speaker 3>there with their lasers and photon counters. This paper brings
<v Speaker 3>them together onto a single chip.
<v Speaker 2>So we have the anion tryon, we have the proof
<v Speaker 2>from the red shift. We have this new optical method.
<v Speaker 2>Let's drill down on the implications. Why does this matter
<v Speaker 2>for the person listening to this right now? What's the takeaway?
<v Speaker 3>I think the simplest way to put it is that
<v Speaker 3>it solves a fundamental read write problem for topological quantum computing.
<v Speaker 2>Okay, break that down. What's the read write problem.
<v Speaker 3>So we've established that the brating of venions is a
<v Speaker 3>great way to store quantum information because it's topologically protected.
<v Speaker 3>That's the memory. But a computer needs more than memory.
<v Speaker 3>You need to be able to write information into the memory,
<v Speaker 3>and you need to be able to read it.
<v Speaker 2>Back out right. A hard drive you can never access
<v Speaker 2>is just a brick.
<v Speaker 3>It's just a brick. And how do you write a braid?
<v Speaker 3>How do you read a braid? Doing it with electrical
<v Speaker 3>currenc is really hard because again the material is an insulator.
<v Speaker 3>You try to push a current through to measure the state,
<v Speaker 3>and you might just destroy the very delicate quantum state
<v Speaker 3>you're trying to measure. You burn the book trying to
<v Speaker 3>read it.
<v Speaker 2>Okay, so electricity is clumsy.
<v Speaker 3>Electricity is clumsy for this. But light we are masters
<v Speaker 3>of controlling light. We have lasers that can be focused
<v Speaker 3>down to the nanoscale. We have fiber optics to route
<v Speaker 3>photons wherever we want. We can control the timing of
<v Speaker 3>laser pulses with femtosecond precision. Light is an incredibly precise tool.
<v Speaker 2>We use photons as flying quibots, that's the term.
<v Speaker 4>Yes.
<v Speaker 3>Photons are perfect for transmitting quantum information over distances. They
<v Speaker 3>move at the speed of light and they don't interact
<v Speaker 3>much with the environment. They're great flying.
<v Speaker 2>Quibots, and anions are great stationary equipots. They're robust for storage, correct.
<v Speaker 3>The problem has always been getting them to talk to
<v Speaker 3>each other. How does the flying equibit transfer its information
<v Speaker 3>to the stationary equibit and vice versa. The nyon tryon
<v Speaker 3>is the missing link. It's the transducer, it's the handshake.
<v Speaker 2>It's the interface that lets the light talk to the
<v Speaker 2>exotic matter.
<v Speaker 4>That's it.
<v Speaker 3>This discovery opens the door to using a precisely aimed
<v Speaker 3>laser pulse to initialize the state of an enion or
<v Speaker 3>to manipulate it, and then using another pulse to read
<v Speaker 3>out its state by looking at the color of the
<v Speaker 3>photon that comes back. It's an all optical interface to
<v Speaker 3>a topological quantum memory, and that.
<v Speaker 2>Sounds like the fundamental building block of something like a
<v Speaker 2>quantum Internet.
<v Speaker 3>It's exactly what you would need. You need nodes that
<v Speaker 3>can store and process quantum information robustly. That's the enians,
<v Speaker 3>and you need a network that can transmit that information
<v Speaker 3>between the nodes, that's the photons. This paper suggests that
<v Speaker 3>this twisted material t mote euro could be the platform
<v Speaker 3>where those two technologies meet.
<v Speaker 2>And I have to come back to this, but the
<v Speaker 2>fact that this all works as zero magnetic field is yeah,
<v Speaker 2>that's the lynchpin, isn't it?
<v Speaker 3>I cannot overstate how important that is. If you need
<v Speaker 3>a giant, power hungry, super cold magnet, your technology is
<v Speaker 3>confined to a national lab. It will never be practical,
<v Speaker 3>never be scalable. But if all you need is the
<v Speaker 3>intrinsic property of the material itself, the anomalous field from
<v Speaker 3>the twist, then you can imagine putting this on a
<v Speaker 3>cell cun chip. You can integrate it into existing semiconductor technology.
<v Speaker 2>It moves it out of the realm of pure science
<v Speaker 2>and into the realm of engineering.
<v Speaker 3>That is the transition from is it possible? To how
<v Speaker 3>do we build it?
<v Speaker 2>So where do they go from here? What's the next
<v Speaker 2>experiment for used team and their collaborators.
<v Speaker 3>The paper gives some strong hints. A huge next step
<v Speaker 3>is achieving what they call spatial localization.
<v Speaker 2>Pinning the innings down right.
<v Speaker 3>Right now in this two D sheet. The innings are
<v Speaker 3>sort of free to drift around in this quantum fluid.
<v Speaker 3>To build a real computer, you need to have your
<v Speaker 3>quibits in specific addressable locations.
<v Speaker 2>You need to know where bit number one is and
<v Speaker 2>bit number two exactly.
<v Speaker 3>So the next engineering challenge is to create what are
<v Speaker 3>called quantum dots. These are like tiny corrals or potential
<v Speaker 3>wells in the material that can trap a single any
<v Speaker 3>on try.
<v Speaker 2>On, you create little parking spots for them.
<v Speaker 3>That's a great way to think of it. And if
<v Speaker 3>you can create an array of these quantum dots, each
<v Speaker 3>holding in any and you can control with a laser,
<v Speaker 3>then you can start to perform operations. You could use
<v Speaker 3>optical tweezers, highly focused lasers to physically move one quantum
<v Speaker 3>dot around another.
<v Speaker 2>You'd be braiding them on purpose.
<v Speaker 3>You'd be performing a topological quantum logic gait. That is
<v Speaker 3>the Hello World program for this kind of computer.
<v Speaker 2>It's still a long road out there.
<v Speaker 3>Very long road, but a critical roadblock has been cleared.
<v Speaker 3>The visibility problem, the how do we even see these
<v Speaker 3>things to know if we've made them? That problem now
<v Speaker 3>has an elegant optical solution.
<v Speaker 2>You Know what's really striking to me as we talk
<v Speaker 2>through this is how much modern physics seems to be
<v Speaker 2>about architecture. We're not necessarily disc covering new fundamental particles
<v Speaker 2>in the way we did with particle colliders. We're not
<v Speaker 2>just smashing things together to see what comes out. It's
<v Speaker 2>a different paradigm it is we're building structures. We're stacking
<v Speaker 2>atomic layers and twisting them to create specific geometric patterns
<v Speaker 2>that compel the universe to manifest these new behaviors, these
<v Speaker 2>new quasi particles.
<v Speaker 3>That is the essence of condensed matter physics.
<v Speaker 4>Today.
<v Speaker 3>We've shifted from being explorers to being architects. We can
<v Speaker 3>write down the Hamiltonian the equation that governs the energy
<v Speaker 3>of the system that we want, and then we try
<v Speaker 3>to engineer a material that produces it. The twist in
<v Speaker 3>the more a lattice is a knob we can turn
<v Speaker 3>to design the interactions.
<v Speaker 2>So the particles have no choice but to follow the
<v Speaker 2>blueprint we've created.
<v Speaker 3>They follow the energy landscape, and from that simple blueprint
<v Speaker 3>you get this incredibly rich complex emergent behavior.
<v Speaker 2>Emergence. That word keeps coming back. The properties of the union,
<v Speaker 2>the fractional charge, the braiding statistics. They don't exist in
<v Speaker 2>a single electron, They don't exist in a single molybdenum atom,
<v Speaker 2>not at all. They exist only in the collective, in
<v Speaker 2>the relationship between all the parts.
<v Speaker 3>The interaction is the reality. The collective defines the properties
<v Speaker 3>of the constituents. It's a profound shift in perspective.
<v Speaker 2>It really is. We started this discussion with today's date, Monday,
<v Speaker 2>February sixteenth, twenty twenty six, a day where we got
<v Speaker 2>this paper showing us that with a little bit of
<v Speaker 2>geometry and a flash of light, the fundamental integers of
<v Speaker 2>the universe aren't quite so fundamental.
<v Speaker 3>After all, the rules are much more interesting and flexible
<v Speaker 3>than the old textbooks. Let on, you just have to
<v Speaker 3>build the right playground for the particles to show you.
<v Speaker 2>I think that's the thought I want to leave everyone
<v Speaker 2>with today. We often think of the life as of
<v Speaker 2>physics and fundamental particles as these rigid, unchangeable things bricks
<v Speaker 2>the universe is built from. But this research shows something different.
<v Speaker 2>It suggests that with the right architecture, with the right geometry,
<v Speaker 2>we can convince reality to remix itself into fractions of
<v Speaker 2>what we thought was indivisible. So if we can effectively
<v Speaker 2>split the unsplitable electron using nothing more than a twist
<v Speaker 2>and a lantern, what other fundamental limits are we imposing
<v Speaker 2>on ourselves that are just waiting for the right structure,
<v Speaker 2>the right twist, to be broken.
<v Speaker 3>That's the question that gets us into the lab every morning.
<v Speaker 2>Thank you for this fascinating analysis. It's been a journey
<v Speaker 2>into a truly new quantum.
<v Speaker 3>World my pleasure. It was a great discussion