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Anyon-Trion Discovery Advances Quantum Materials Research · The Quark Side - Quantum Physics Podcast

0:01
Speaker 1: Welcome to the Court Side Quantum Physics Podcast, an exploration
0:05
Speaker 1: of the fundamental structure of reality, where quantum laws govern matter, energy,
0:11
Speaker 1: and information. Here, uncertainty is a feature, not a flaw,
0:16
Speaker 1: and understanding begins at the smallest scales.
0:27
Speaker 2: It is Monday, February sixteenth, twenty twenty six. And you know,
0:31
Speaker 2: sometimes you come in on a Monday and look at
0:33
Speaker 2: the research that's just been published and you see something
0:36
Speaker 2: that frankly shouldn't exist.
0:39
Speaker 3: Uh yeah, something that breaks the old textbooks for sure.
0:41
Speaker 2: It absolutely does. We are doing an analysis today of
0:44
Speaker 2: a paper that just dropped in Nature. It's a huge collaboration.
0:48
Speaker 2: We're talking University of Washington, Nim's in Japan, Eth.
0:52
Speaker 3: Zurich, a real powerhouse group.
0:54
Speaker 2: It is. The title is a bit of a mouthful,
0:58
Speaker 2: using light to probe fractional charges in a fractional churn insulator.
1:03
Speaker 2: But what it really means, if I'm getting this right,
1:05
Speaker 2: is that scientists have found a way to see pieces
1:07
Speaker 2: of an electron.
1:08
Speaker 3: Well, let's be super careful with the language right at
1:10
Speaker 3: the start. Okay, they haven't taken like a tiny knife
1:13
Speaker 3: and physically chopped up an electron. That would well, that
1:16
Speaker 3: would up end the standard model and probably break physics
1:18
Speaker 3: as we know it.
1:19
Speaker 2: Right, No knives involved, no knives, But.
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Speaker 3: We have done something that, for all practical purposes, looks
1:24
Speaker 3: and acts exactly like that. We've created and then observed
1:28
Speaker 3: a state of matter where electricity doesn't flow in units
1:31
Speaker 3: of one electron. It flows in units of say one
1:34
Speaker 3: third of an.
1:34
Speaker 2: Electron, which is the very definition of a fractional charge.
1:38
Speaker 2: Something that just sounds impossible on its face.
1:40
Speaker 4: It does.
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Speaker 3: And the big news here, the real headline isn't just
1:44
Speaker 3: that these things exist. We've had hints of that for decades,
1:47
Speaker 3: you know, in these massive high magnetic field experiments.
1:50
Speaker 2: Trying to take up a whole room and need cryo
1:51
Speaker 2: cooling exactly.
1:53
Speaker 3: The headline is that this team found a way to
1:55
Speaker 3: see them, to optically detect them. They just they shone
1:58
Speaker 3: a light on the material and they could read the
2:00
Speaker 3: signature of this ghost particle.
2:03
Speaker 2: The ghost particle. Okay, we need to unpack that and
2:06
Speaker 2: the lantern they used to see it. But before we
2:09
Speaker 2: get to the ghost in the lantern, we have to
2:11
Speaker 2: build the stage right the environment where this can even happen.
2:14
Speaker 3: We have to build a haunted house.
2:15
Speaker 2: The haunted house. I like that because this phenomenon doesn't
2:19
Speaker 2: just happen in a normal copper wire, does it. You
2:22
Speaker 2: can't just find fractional electrons in the wiring in your walls.
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Speaker 3: Not at all. No, you need a very specific, meticulously
2:30
Speaker 3: engineered environment. You need something called a more superlattice.
2:34
Speaker 2: Okay more that's a term I recognize from like photography
2:38
Speaker 2: or TV. If you wear a shirt with really fine stripes,
2:42
Speaker 2: the camera creates this weird, wavy shimmering pattern.
2:45
Speaker 3: That is precisely what it is. But instead of camera
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Speaker 3: pixels and shirt threads, we're talking about atoms in.
2:50
Speaker 4: A crystal on an atomic scale exactly.
2:53
Speaker 3: The material itself is called twisted bill ayer molybdenum detelluride.
2:57
Speaker 3: The shorthand is tmote you.
2:59
Speaker 2: Right, And for people following this space, the first question
3:02
Speaker 2: might be why not graphene. You know, graphene has been
3:05
Speaker 2: the wonder material for what twenty years now.
3:08
Speaker 3: Graphene is amazing, don't get me wrong, but graphene is
3:10
Speaker 3: what we call a semi metal. It doesn't have a
3:12
Speaker 3: natural band gap, which limits some of its electronic and
3:15
Speaker 3: optical properties. This material moliditum. To tell your ide is
3:18
Speaker 3: a semiconductor, so it.
3:20
Speaker 2: Has a different set of rules for how its electrons can.
3:22
Speaker 3: Behave a very different playbook. And the real magic, the
3:26
Speaker 3: part that makes this whole thing possible, is in the
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Speaker 3: twisted bill layer part of the name the twist.
3:31
Speaker 4: The twist.
3:32
Speaker 3: You take one sheet of this material, which is just
3:34
Speaker 3: one atom thick. Then you take a second sheet and
3:37
Speaker 3: you lay it on top. But and this is the key,
3:39
Speaker 3: you don't line them up perfectly. You twist the top
3:42
Speaker 3: layer just a tiny, tiny bit. We're talking between three
3:46
Speaker 3: and four degrees, a very specific small angle, and.
3:49
Speaker 2: That little twist changes everything.
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Speaker 3: It changes absolutely everything. When you misalign the atomic grids
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Speaker 3: of the two layers, this new larger scale pattern emerges.
3:59
Speaker 3: Just like your screen door analogy, you get these big
4:02
Speaker 3: repeating hexagonal cells. That new larger pattern is the more superlattice.
4:07
Speaker 2: So you're not changing the atoms, you're changing the geometry.
4:11
Speaker 2: You're creating a new landscape for the electrons to live in.
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Speaker 3: You're creating a new potential energy landscape. And that is
4:17
Speaker 3: the crucial insight. Think of electrons in a normal metal
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Speaker 3: like copper. They're like race cars on a perfectly smooth
4:24
Speaker 3: flat race track. Their kinetic energy is really.
4:27
Speaker 2: High, so they're just zipping around everywhere.
4:29
Speaker 3: Zipping around, and they're moving so fast that they mostly
4:32
Speaker 3: ignore each other. The repulsion between them doesn't have much
4:35
Speaker 3: effect because their momentum is the dominant factor.
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Speaker 2: They're too busy moving to interact.
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Speaker 3: Right, But this more pattern, It's like putting a whole
4:44
Speaker 3: grid of speed bumps all over the racetrack. It fundamentally
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Speaker 3: changes the energy structure. It creates what physicists call flat
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Speaker 3: bands flat bands.
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Speaker 2: I saw that term all over the paper and sounds counterintuitive.
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Speaker 2: You'd think flat means they can go faster.
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Speaker 3: The opposite, a flat energy band means the kinetic energy,
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Speaker 3: the energy of motion gets quenched. It drops to almost zero.
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Speaker 3: The electrons basically grind to a halt.
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Speaker 2: So the race cars are now stuck in a massive traffic.
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Speaker 3: Jam, a quantum traffic jam. And what happens when you're
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Speaker 3: suck in traffic You can't ignore the cars around you anymore.
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Speaker 3: Suddenly the interactions between them become the most important thing.
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Speaker 2: The cool long interaction, the fact that they're all negatively
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Speaker 2: charged and they all want to get away from each
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Speaker 2: other exactly.
5:27
Speaker 3: That repulsion becomes the dominant force in their universe. They
5:31
Speaker 3: can't just run away, so they have to organize. They
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Speaker 3: have to arrange themselves in a very specific collective dance
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Speaker 3: to minimize their total energy, a coordinated dance, and it
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Speaker 3: is that collective correlated behavior that gives rise to these
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Speaker 3: incredible new states of matter. The system as a whole
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Speaker 3: starts acting in ways that none of the individual electrons.
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Speaker 2: Could, and that specific state is what they're calling a
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Speaker 2: fractional churn insulator.
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Speaker 3: That's the one and each of those words is important.
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Speaker 3: We have the fractional part, which we'll get to. We
6:03
Speaker 3: have the insulator part, meaning it doesn't conduct electricity in
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Speaker 3: a normal way, and then we have the churn part, churn.
6:09
Speaker 2: That refers to the topology, right it does, so topology.
6:13
Speaker 2: Most people hear that and think of the coffee mug
6:15
Speaker 2: and donut analogy. You know, they're the same because they
6:18
Speaker 2: each have one.
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Speaker 3: Hole, and that's a perfect starting point. Topology is about
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Speaker 3: properties that are robust that don't change if you sort
6:26
Speaker 3: of stretch or bend the system without tearing it. In
6:29
Speaker 3: this material, the quantum wave functions of the electrons get
6:33
Speaker 3: twisted into a topologically non trivial knot.
6:36
Speaker 4: I'm not a mathematical.
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Speaker 3: Knot, and that intrinsic twist in the system acts like
6:41
Speaker 3: a built in magnetic field, an incredibly powerful.
6:44
Speaker 2: One built in so you don't need to put the
6:46
Speaker 2: sample inside a giant magnet.
6:48
Speaker 3: And that is the single biggest practical advantage here. That's
6:51
Speaker 3: the anomalist part of the name. They use the fractional
6:54
Speaker 3: quantum anomalis Hall effect.
6:55
Speaker 2: Okay, let's slow down there. The original fractional quantum Hall effect,
6:58
Speaker 2: the one that won the Nobel Prize. That required massive magnets.
7:03
Speaker 3: Right massive. We're talking magnetic fields hundreds of thousands of
7:06
Speaker 3: times stronger than the Earth's. You need huge room size
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Speaker 3: superconducting magnets to force the electrons into this correlated state.
7:15
Speaker 2: Which is fantastic for fundamental physics research, but you're never
7:18
Speaker 2: going to build a computer out of it. You can't
7:19
Speaker 2: put a twenty tesla magnet in your phone exactly.
7:22
Speaker 3: It's just not a scalable technology. But in this material,
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Speaker 3: the more a twist is the magnet. The geometry itself
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Speaker 3: generates when we call a Barry curvature, which is like
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Speaker 3: a fictitious internal magnetic field that does all the work
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Speaker 3: for us.
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Speaker 2: So you get all the exotic physics of a huge
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Speaker 2: magnetic field, but it's zero external field.
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Speaker 1: Zero.
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Speaker 3: That's the game changer for any future applications.
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Speaker 2: Okay, so the stage is set. Okay, we have this
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Speaker 2: twisted bi layer of molybdenum detelluride. The floor is a
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Speaker 2: grid of quantum speed bumps that slows the electrons down,
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Speaker 2: forces them to dance together into this topological state. Now
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Speaker 2: let's bring on the ghost, the Aenian, the Anian. I
8:02
Speaker 2: have to ask the fundamental question here is an anian?
8:05
Speaker 2: Is it a real particle or is it just a
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Speaker 2: useful mathematical fiction. When I hear quasi particle, my brain
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Speaker 2: immediately translates that to sort of a fake particle.
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Speaker 3: That's a great question, and it's almost as much a
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Speaker 3: philosophical one as a physical one. Let me ask you,
8:17
Speaker 3: this is a wave in the ocean real?
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Speaker 2: I mean, yeah, if it hits you, you get wet.
8:22
Speaker 2: The water is real, the energy moving through it is real. Yeah,
8:25
Speaker 2: so the phenomenon is.
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Speaker 3: Real exactly, And anion is a quasi particle, which means
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Speaker 3: it's a collective excitation. It's not a fundamental particle like
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Speaker 3: an electron or a quark that you'd find in the
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Speaker 3: standard model. It's an emergent phenomenon. It's the wave, not
8:40
Speaker 3: the water molecule.
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Speaker 2: Okay, I can see that it's a disturbance in the
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Speaker 2: electron soup.
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Speaker 3: It's a disturbance. But in the quantum world, if it
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Speaker 3: has well defined properties, if it has a measurable charge,
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Speaker 3: a measurable mass, if it behaves like a particle, then
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Speaker 3: for all intents and purposes, it is a particle within
8:57
Speaker 3: that material, and.
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Speaker 2: Its properties are just bizarre.
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Speaker 1: They are.
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Speaker 3: The charge isn't heminal one like an electron in this state,
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Speaker 3: it can be ninetag thirteen or negeta twenty three of
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Speaker 3: the elementary charge.
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Speaker 2: That just breaks my brain. Everything we learn in school
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Speaker 2: is that charge is quantized. It comes into multiples of e.
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Speaker 2: You can have one electron or two or one hundred.
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Speaker 2: You can't have a third of one.
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Speaker 3: In free space you can't. But inside this very specific
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Speaker 3: correlated state of matter you can. It's not a glitch
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Speaker 3: in the matrix. It's a feature of this unique topological order.
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Speaker 2: And it's not just the fractional charge. You mentioned something else,
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Speaker 2: fractional statistics.
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Speaker 3: What does that mean, this is maybe the weirdest and
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Speaker 3: most important part in our three D world. All particles
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Speaker 3: are either fermions like electrons, or bosons like photons. If
9:45
Speaker 3: you take two identical fermions and swap their positions, the
9:48
Speaker 3: total quantum wave function gets a minus sign. If you
9:51
Speaker 3: swap two bosons, nothing changes. It's a binary choice.
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Speaker 2: Okay, metas one or plus one.
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Speaker 3: Right, But in two dimensional systems like this material, a
10:00
Speaker 3: third possibility exists. These quasi particles are aenions because when
10:05
Speaker 3: you swap two of them, the wave function can pick
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Speaker 3: up any phase, not just plus one or neck as one.
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Speaker 4: So like a fraction of a phase exactly.
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Speaker 3: And this has a profound consequence. Imagine you take one
10:16
Speaker 3: enion and loop it around another one and bring it
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Speaker 3: back to where it started. The system remembers that you
10:21
Speaker 3: did that.
10:21
Speaker 2: The system keeps a record of their history.
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Speaker 3: It keeps a record. It's like braiding strands of hair.
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Speaker 3: If you braid two strands, you've created a permanent topological
10:30
Speaker 3: link between them. You can't undo it by just jiggling
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Speaker 3: them locally. That braid is a form of information, and that's.
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Speaker 2: The topological protection that everyone talks about for quantum computing.
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Speaker 3: That's the holy grail. A normal quantum bit equivot might
10:42
Speaker 3: be stored in the spin of a single electron. It's
10:45
Speaker 3: incredibly fragile. A stray magnetic field, a tiny vibration can
10:50
Speaker 3: come in and flip the spin, destroying your information.
10:53
Speaker 2: Decoherence.
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Speaker 3: Decoherence the mortal enemy of quantum computing. But if your
10:58
Speaker 3: information is stored in the braid of these anions, in
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Speaker 3: the topology of their world lines, it's robust. Local noise
11:06
Speaker 3: can't untie the knot. To destroy the information, you have
11:10
Speaker 3: to do something catastrophic to the whole system.
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Speaker 2: So inions of the basis for a fault tolerant quip.
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Speaker 3: That's the dream. But there's always been this huge practical problem.
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Speaker 3: Anies are shy. They live deep inside this insulating state,
11:23
Speaker 3: and an insulator, by its very definition, doesn't conduct electricity well.
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Speaker 2: So you can't just plug in a multimeter measure them easily.
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Speaker 3: It's incredibly difficult. The traditional method is called a transport measurement.
11:33
Speaker 3: You have to physically attach tiny wires or contacts to
11:36
Speaker 3: a flake of material. It's only two atoms thick. It's invasive,
11:39
Speaker 3: it can damage the sample, and it usually only tells
11:42
Speaker 3: you what's happening at the very edge of the material.
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Speaker 2: It's like trying to figure out what's happening inside a
11:46
Speaker 2: packed stadium by just looking at who is coming.
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Speaker 3: In and out of the main gate, a perfect analogy.
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Speaker 3: You have no idea what's happening in the stands. This
11:56
Speaker 3: is why this new paper is such a big deal.
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Speaker 3: The researchers that you UW decided to stop trying to
12:02
Speaker 3: listen at the door. They decided to find a way
12:04
Speaker 3: to look through the windows with a flashlight, with a
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Speaker 3: quantum flashlight.
12:09
Speaker 2: Okay, so let's talk about the flashlight. This is the tryon,
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Speaker 2: the tryon. Yes, this part of the paper felt like
12:14
Speaker 2: a real detective story. They knew the ghost the anion
12:17
Speaker 2: was in the house, but they needed a way to
12:19
Speaker 2: see it, so they had to invent a ghost detector.
12:23
Speaker 2: What exactly is a tryon?
12:25
Speaker 3: Okay, to get to a try on, you first have
12:27
Speaker 3: to understand.
12:28
Speaker 4: And excitement right step by step.
12:30
Speaker 3: You take your semiconductor material, you shine a laser on it.
12:33
Speaker 3: A photon from the laser comes in and it has
12:36
Speaker 3: enough energy to hit an electron and kick it out
12:38
Speaker 3: of its comfortable home state into a higher energy level.
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Speaker 2: Okay, it promotes the electron.
12:43
Speaker 3: It does, and when the electron leaves, it leaves behind
12:46
Speaker 3: a vacancy, a hole. It's like you standing up from
12:49
Speaker 3: your chair in a crowded theater. The chair is now empty.
12:53
Speaker 2: And in semiconductor physics, that hole isn't just nothingness. It
12:58
Speaker 2: acts like a particle itself.
12:59
Speaker 3: It acts like a positively charged particle. So now you
13:02
Speaker 3: have this negatively charged electron that you just picked up
13:06
Speaker 3: and this positively charged hole that it left behind.
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Speaker 4: Opposites attract, so they stick together.
13:11
Speaker 3: They get bound to each other by the electrostatic force,
13:14
Speaker 3: and they orbit each other. That bound pair the electron
13:17
Speaker 3: and the hole is an excitant, and because it's a
13:19
Speaker 3: nice one and a plus one, its total charge is zero.
13:22
Speaker 3: It's neutral.
13:23
Speaker 2: Got it. Excitan equals a neutral pair.
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Speaker 3: Now imagine that neutral excitan is drifting through our material,
13:29
Speaker 3: through this quantum traffic jam of electrons, and it bumps
13:32
Speaker 3: into one of the extra free electrons that are just
13:34
Speaker 3: part of.
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Speaker 2: The system, and it picks it up like a little
13:37
Speaker 2: pac men.
13:37
Speaker 3: It grabs it. The attraction is strong enough to bind
13:40
Speaker 3: that third particle. So now you have a cluster of
13:42
Speaker 3: three things two electrons and one hole.
13:45
Speaker 2: That is a try on two electrons, one hole, so
13:48
Speaker 2: its net charge is negative.
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Speaker 3: One precisely unlike the exciting, the trion is a charged particle.
13:55
Speaker 3: And here's the other crucial piece. Like the exciting, it's optically.
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Speaker 2: Active, meaning it can absorb and emit light.
14:02
Speaker 3: Yes, eventually one of the electrons will fall back into
14:06
Speaker 3: the hole to annihilate it, and when it does, it
14:08
Speaker 3: releases that energy as a photon of light, a flash.
14:12
Speaker 3: So what you have in a trian is the perfect spy.
14:15
Speaker 3: It's a particle that is sensitive to the electric fields
14:17
Speaker 3: around it because it's charged, and it reports back on
14:20
Speaker 3: its local environment by emitting light at a very specific
14:24
Speaker 3: color or frequency.
14:25
Speaker 2: It's a sensor that glows.
14:26
Speaker 4: A lantern is the lantern.
14:28
Speaker 2: So the big idea from the lead researcher, shadlung Shoe
14:31
Speaker 2: and his group was what if we put these lanterns
14:35
Speaker 2: into our haunted house. What happens if a tryan meets
14:37
Speaker 2: an anion.
14:38
Speaker 3: The central hypothesis was that they would bind together, they'd
14:41
Speaker 3: stick to each other. Yes, you have the negatively charged
14:44
Speaker 3: trian and you have the fractionally charged anion, which is
14:48
Speaker 3: also effectively negative. Now, you'd think two negative things would
14:51
Speaker 3: just repel each other.
14:52
Speaker 2: Right, like pushing two magnets together the wrong way.
14:55
Speaker 3: But because of the complex many body interactions in this
14:57
Speaker 3: correlated state, the prediction was that they would actually feel
15:01
Speaker 3: an attractive force. They would form a new composite quasi particle,
15:06
Speaker 3: an anian tryon, the anyan tryon, a new kind of
15:10
Speaker 3: fractional charge excitonic state.
15:12
Speaker 2: That sounds like something straight out of science fiction. But
15:15
Speaker 2: if this binding happens, what's the evidence? How would you
15:18
Speaker 2: ever know that they've actually paired up.
15:19
Speaker 3: In physics, everything wants to find its lowest possible energy state.
15:23
Speaker 3: It's like a ball wanting to roll downhill. If two
15:26
Speaker 3: particles can lower their total energy by sticking together, they will.
15:30
Speaker 3: That missing energy is the binding energy. It's the glue
15:33
Speaker 3: holding them together.
15:35
Speaker 2: And energy is related to light.
15:36
Speaker 3: The color, energy and the frequency of light are directly proportional.
15:41
Speaker 3: High energy means high frequency, which is bluer light. Low
15:44
Speaker 3: energy means low frequency, which is redder light.
15:46
Speaker 2: So if a normal tri in of it's a photon
15:48
Speaker 2: of a certain color, then a.
15:49
Speaker 3: Tryon that's bound to an anion which is now in
15:52
Speaker 3: a lower energy state should emit a photon with less energy.
15:56
Speaker 3: When it decays, the light it emits should be shifted
15:59
Speaker 3: towards the red.
16:00
Speaker 4: End of the spectrum, a red shift.
16:01
Speaker 3: A red shift. That was the smoking dun they were
16:03
Speaker 3: looking for. Yeah, a new flash of light at a
16:05
Speaker 3: new color that only appears when the conditions are perfect
16:09
Speaker 3: for anians to exist.
16:10
Speaker 2: Okay, so let's walk through the experiment itself. They build
16:13
Speaker 2: the device, this twisted bilayer sandwich. What's next.
16:17
Speaker 3: The next step is incredibly delicate. It's called doping. They
16:21
Speaker 3: use an electric field applied by a nearby gait electrode
16:24
Speaker 3: to very carefully add or remove electrons from the material.
16:28
Speaker 3: They have to tune the electron density with exquisite precision.
16:31
Speaker 2: It's like tuning an old analog radio dial trying to
16:34
Speaker 2: find that one feint station.
16:35
Speaker 3: That is a perfect analogy. You have to turn the
16:38
Speaker 3: knob just so. If you have too many electrons, the
16:41
Speaker 3: system just becomes a boring metal. If you have too few,
16:44
Speaker 3: it's a boring insulator. But if you hit the density
16:47
Speaker 3: just right at what they call a filling factor of
16:49
Speaker 3: say negative twenty three.
16:51
Speaker 2: Meaning for every three spots in the more a lattice
16:54
Speaker 2: there are two electrons.
16:55
Speaker 3: Exactly when you hit that magic fraction, the electrons spontaneously
16:59
Speaker 3: organized into this fractional churn insulator state. The Aenians emerge.
17:04
Speaker 2: And once they've tuned the dial and the en needs
17:05
Speaker 2: are there, mm hmm, they turn on the laser.
17:08
Speaker 3: They turn on the laser. This technique is called photoluminescence spectroscopy.
17:13
Speaker 3: They shine light of one color in and they use
17:15
Speaker 3: a very sensitive detector to measure the colors of light
17:18
Speaker 3: that come back out.
17:19
Speaker 2: And what do they see on their screen?
17:21
Speaker 3: They saw a new peak emerge in the spectrum at
17:24
Speaker 3: filling factors where nothing interesting should be happening. They saw
17:27
Speaker 3: the expected peaks for regular excitans and trans But as
17:31
Speaker 3: soon as they tuned the system into that Negavit twenty
17:34
Speaker 3: three state, a new signal.
17:36
Speaker 2: Appeared, a new line on the graph, a.
17:38
Speaker 3: Bright, sharp, new emission line, and it was exactly where
17:41
Speaker 3: they predicted it would be. It was red shifted. It
17:43
Speaker 3: was at a lower energy than the normal triand.
17:45
Speaker 2: So that's the evidence of binding. The energy difference between
17:47
Speaker 2: the normal try and peak and this new Innian tryon
17:51
Speaker 2: peak is the glue.
17:52
Speaker 3: That is the binding energy. But here's the part that
17:55
Speaker 3: makes it undeniable, the part that rules out other explanations.
17:59
Speaker 3: The first author on the paper, Ugli, pointed this out.
18:02
Speaker 3: The amount of the energy shift, the size of the
18:05
Speaker 3: red shift wasn't random. It scaled directly with the magnitude
18:08
Speaker 3: of the fractional charge. When they created a state with
18:11
Speaker 3: menic of thirteen chargeenians, they got one specific red shift.
18:16
Speaker 3: When they created a state with the menics of twenty
18:18
Speaker 3: three charge Enians, the red shift was different. It was stronger.
18:21
Speaker 2: Whoa, So the light itself was carrying the fingerprint of
18:24
Speaker 2: the fraction It wasn't just telling them something is here,
18:28
Speaker 2: It was telling them what is here.
18:29
Speaker 3: They were, in effect optically reading the fractional charge of
18:33
Speaker 3: the Enian. They were measuring a fundamental property of this
18:36
Speaker 3: exotic quasi particle without ever touching it with a wire.
18:40
Speaker 3: It's the first time anyone has done this in one
18:42
Speaker 3: of these zero field fractional churn insulators.
18:45
Speaker 2: That's just it's an incredibly elegant piece of physics. It's
18:49
Speaker 2: like they figured out how to make the ghost glow
18:51
Speaker 2: in the dark, and the color it glows tells you
18:53
Speaker 2: exactly what kind of ghost it is.
18:54
Speaker 3: It is, and it opens up a whole new toolbox.
18:57
Speaker 3: It builds a bridge between two massive fields of physics
19:00
Speaker 3: that don't always interact this directly, the world of correlated topology,
19:04
Speaker 3: which studies these weird collective states, and the world.
19:07
Speaker 2: Of quantum optics, which studies how light and matter interact
19:10
Speaker 2: at the single particle level exactly.
19:13
Speaker 3: Usually, the topology people are over here where they're giant
19:15
Speaker 3: magnets and dilution refrigerators, and the optics people are over
19:19
Speaker 3: there with their lasers and photon counters. This paper brings
19:23
Speaker 3: them together onto a single chip.
19:25
Speaker 2: So we have the anion tryon, we have the proof
19:27
Speaker 2: from the red shift. We have this new optical method.
19:29
Speaker 2: Let's drill down on the implications. Why does this matter
19:33
Speaker 2: for the person listening to this right now? What's the takeaway?
19:36
Speaker 3: I think the simplest way to put it is that
19:38
Speaker 3: it solves a fundamental read write problem for topological quantum computing.
19:42
Speaker 2: Okay, break that down. What's the read write problem.
19:45
Speaker 3: So we've established that the brating of venions is a
19:47
Speaker 3: great way to store quantum information because it's topologically protected.
19:51
Speaker 3: That's the memory. But a computer needs more than memory.
19:54
Speaker 3: You need to be able to write information into the memory,
19:57
Speaker 3: and you need to be able to read it.
19:58
Speaker 2: Back out right. A hard drive you can never access
20:01
Speaker 2: is just a brick.
20:02
Speaker 3: It's just a brick. And how do you write a braid?
20:05
Speaker 3: How do you read a braid? Doing it with electrical
20:08
Speaker 3: currenc is really hard because again the material is an insulator.
20:11
Speaker 3: You try to push a current through to measure the state,
20:14
Speaker 3: and you might just destroy the very delicate quantum state
20:16
Speaker 3: you're trying to measure. You burn the book trying to
20:18
Speaker 3: read it.
20:19
Speaker 2: Okay, so electricity is clumsy.
20:21
Speaker 3: Electricity is clumsy for this. But light we are masters
20:25
Speaker 3: of controlling light. We have lasers that can be focused
20:27
Speaker 3: down to the nanoscale. We have fiber optics to route
20:30
Speaker 3: photons wherever we want. We can control the timing of
20:33
Speaker 3: laser pulses with femtosecond precision. Light is an incredibly precise tool.
20:39
Speaker 2: We use photons as flying quibots, that's the term.
20:44
Speaker 4: Yes.
20:44
Speaker 3: Photons are perfect for transmitting quantum information over distances. They
20:48
Speaker 3: move at the speed of light and they don't interact
20:50
Speaker 3: much with the environment. They're great flying.
20:53
Speaker 2: Quibots, and anions are great stationary equipots. They're robust for storage, correct.
20:58
Speaker 3: The problem has always been getting them to talk to
21:00
Speaker 3: each other. How does the flying equibit transfer its information
21:03
Speaker 3: to the stationary equibit and vice versa. The nyon tryon
21:07
Speaker 3: is the missing link. It's the transducer, it's the handshake.
21:11
Speaker 2: It's the interface that lets the light talk to the
21:14
Speaker 2: exotic matter.
21:15
Speaker 4: That's it.
21:15
Speaker 3: This discovery opens the door to using a precisely aimed
21:19
Speaker 3: laser pulse to initialize the state of an enion or
21:22
Speaker 3: to manipulate it, and then using another pulse to read
21:25
Speaker 3: out its state by looking at the color of the
21:27
Speaker 3: photon that comes back. It's an all optical interface to
21:31
Speaker 3: a topological quantum memory, and that.
21:33
Speaker 2: Sounds like the fundamental building block of something like a
21:36
Speaker 2: quantum Internet.
21:37
Speaker 3: It's exactly what you would need. You need nodes that
21:39
Speaker 3: can store and process quantum information robustly. That's the enians,
21:43
Speaker 3: and you need a network that can transmit that information
21:46
Speaker 3: between the nodes, that's the photons. This paper suggests that
21:49
Speaker 3: this twisted material t mote euro could be the platform
21:53
Speaker 3: where those two technologies meet.
21:55
Speaker 2: And I have to come back to this, but the
21:56
Speaker 2: fact that this all works as zero magnetic field is yeah,
22:00
Speaker 2: that's the lynchpin, isn't it?
22:01
Speaker 3: I cannot overstate how important that is. If you need
22:05
Speaker 3: a giant, power hungry, super cold magnet, your technology is
22:09
Speaker 3: confined to a national lab. It will never be practical,
22:12
Speaker 3: never be scalable. But if all you need is the
22:15
Speaker 3: intrinsic property of the material itself, the anomalous field from
22:19
Speaker 3: the twist, then you can imagine putting this on a
22:22
Speaker 3: cell cun chip. You can integrate it into existing semiconductor technology.
22:26
Speaker 2: It moves it out of the realm of pure science
22:28
Speaker 2: and into the realm of engineering.
22:29
Speaker 3: That is the transition from is it possible? To how
22:34
Speaker 3: do we build it?
22:35
Speaker 2: So where do they go from here? What's the next
22:36
Speaker 2: experiment for used team and their collaborators.
22:39
Speaker 3: The paper gives some strong hints. A huge next step
22:42
Speaker 3: is achieving what they call spatial localization.
22:45
Speaker 2: Pinning the innings down right.
22:47
Speaker 3: Right now in this two D sheet. The innings are
22:49
Speaker 3: sort of free to drift around in this quantum fluid.
22:52
Speaker 3: To build a real computer, you need to have your
22:54
Speaker 3: quibits in specific addressable locations.
22:57
Speaker 2: You need to know where bit number one is and
22:58
Speaker 2: bit number two exactly.
23:00
Speaker 3: So the next engineering challenge is to create what are
23:03
Speaker 3: called quantum dots. These are like tiny corrals or potential
23:07
Speaker 3: wells in the material that can trap a single any
23:10
Speaker 3: on try.
23:11
Speaker 2: On, you create little parking spots for them.
23:13
Speaker 3: That's a great way to think of it. And if
23:15
Speaker 3: you can create an array of these quantum dots, each
23:18
Speaker 3: holding in any and you can control with a laser,
23:20
Speaker 3: then you can start to perform operations. You could use
23:23
Speaker 3: optical tweezers, highly focused lasers to physically move one quantum
23:28
Speaker 3: dot around another.
23:29
Speaker 2: You'd be braiding them on purpose.
23:31
Speaker 3: You'd be performing a topological quantum logic gait. That is
23:35
Speaker 3: the Hello World program for this kind of computer.
23:39
Speaker 2: It's still a long road out there.
23:40
Speaker 3: Very long road, but a critical roadblock has been cleared.
23:44
Speaker 3: The visibility problem, the how do we even see these
23:47
Speaker 3: things to know if we've made them? That problem now
23:50
Speaker 3: has an elegant optical solution.
23:52
Speaker 2: You Know what's really striking to me as we talk
23:54
Speaker 2: through this is how much modern physics seems to be
23:57
Speaker 2: about architecture. We're not necessarily disc covering new fundamental particles
24:01
Speaker 2: in the way we did with particle colliders. We're not
24:04
Speaker 2: just smashing things together to see what comes out. It's
24:06
Speaker 2: a different paradigm it is we're building structures. We're stacking
24:10
Speaker 2: atomic layers and twisting them to create specific geometric patterns
24:14
Speaker 2: that compel the universe to manifest these new behaviors, these
24:18
Speaker 2: new quasi particles.
24:19
Speaker 3: That is the essence of condensed matter physics.
24:21
Speaker 4: Today.
24:22
Speaker 3: We've shifted from being explorers to being architects. We can
24:25
Speaker 3: write down the Hamiltonian the equation that governs the energy
24:28
Speaker 3: of the system that we want, and then we try
24:30
Speaker 3: to engineer a material that produces it. The twist in
24:33
Speaker 3: the more a lattice is a knob we can turn
24:35
Speaker 3: to design the interactions.
24:36
Speaker 2: So the particles have no choice but to follow the
24:39
Speaker 2: blueprint we've created.
24:40
Speaker 3: They follow the energy landscape, and from that simple blueprint
24:43
Speaker 3: you get this incredibly rich complex emergent behavior.
24:47
Speaker 2: Emergence. That word keeps coming back. The properties of the union,
24:51
Speaker 2: the fractional charge, the braiding statistics. They don't exist in
24:54
Speaker 2: a single electron, They don't exist in a single molybdenum atom,
24:59
Speaker 2: not at all. They exist only in the collective, in
25:02
Speaker 2: the relationship between all the parts.
25:04
Speaker 3: The interaction is the reality. The collective defines the properties
25:07
Speaker 3: of the constituents. It's a profound shift in perspective.
25:11
Speaker 2: It really is. We started this discussion with today's date, Monday,
25:15
Speaker 2: February sixteenth, twenty twenty six, a day where we got
25:18
Speaker 2: this paper showing us that with a little bit of
25:20
Speaker 2: geometry and a flash of light, the fundamental integers of
25:23
Speaker 2: the universe aren't quite so fundamental.
25:25
Speaker 3: After all, the rules are much more interesting and flexible
25:28
Speaker 3: than the old textbooks. Let on, you just have to
25:30
Speaker 3: build the right playground for the particles to show you.
25:33
Speaker 2: I think that's the thought I want to leave everyone
25:35
Speaker 2: with today. We often think of the life as of
25:37
Speaker 2: physics and fundamental particles as these rigid, unchangeable things bricks
25:42
Speaker 2: the universe is built from. But this research shows something different.
25:47
Speaker 2: It suggests that with the right architecture, with the right geometry,
25:50
Speaker 2: we can convince reality to remix itself into fractions of
25:54
Speaker 2: what we thought was indivisible. So if we can effectively
25:57
Speaker 2: split the unsplitable electron using nothing more than a twist
26:01
Speaker 2: and a lantern, what other fundamental limits are we imposing
26:05
Speaker 2: on ourselves that are just waiting for the right structure,
26:08
Speaker 2: the right twist, to be broken.
26:10
Speaker 3: That's the question that gets us into the lab every morning.
26:12
Speaker 2: Thank you for this fascinating analysis. It's been a journey
26:15
Speaker 2: into a truly new quantum.
26:17
Speaker 3: World my pleasure. It was a great discussion