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A New Quantum State Could Transform What We Can Build on a Chip · The Quark Side - Quantum Physics Podcast

• 0:01
  Speaker 1: Welcome to the quart 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: I want you to imagine, just for a second, going
• 0:29
  Speaker 2: out and buying like a brand new laptop, but instead
• 0:32
  Speaker 2: of those tiny metal wires routing electrons all around the motherboard,
• 0:36
  Speaker 2: the inside of your computer's processor is just filled with
• 0:39
  Speaker 2: this frictionless, glowing liquid. Oh wow, yeah right. And instead
• 0:44
  Speaker 2: of countless individual particles bouncing around doing all the work,
• 0:48
  Speaker 2: that liquid acts as a single giant, synchronized artificial atom
• 0:53
  Speaker 2: spanning the entire chip.
• 0:55
  Speaker 3: I mean, it sounds like pure science fiction, but you
• 0:58
  Speaker 3: are actually describing a state of matter that physicists have
• 1:01
  Speaker 3: been wrestling with for gosh, almost a century now. We're
• 1:04
  Speaker 3: talking about a Bose Einstein condensate or a BEC. It's
• 1:09
  Speaker 3: the state where that fundamental rules of the universe seem
• 1:11
  Speaker 3: to just give up their usual boundaries, you.
• 1:13
  Speaker 2: Know, right, Because normally we think of matter as like
• 1:16
  Speaker 2: discrete things, right, electron over here, a proton over.
• 1:19
  Speaker 3: There, exactly. But when you create a BEC, those individual
• 1:22
  Speaker 3: identities just dissolve completely.
• 1:24
  Speaker 2: I've always found the whole concept of a bec fascinating
• 1:28
  Speaker 2: because it really forces us to confront way of particle duality.
• 1:33
  Speaker 2: Usually particles act like little billiard balls, but if you
• 1:36
  Speaker 2: get them cold enough, they start acting more like waves. Well,
• 1:39
  Speaker 2: they blur together, right, they blur together until you literally
• 1:42
  Speaker 2: cannot tell one particle from another. But the problem is, historically,
• 1:48
  Speaker 2: forcing matter to do this has been an absolute nightmare
• 1:51
  Speaker 2: of engineering, like trying to build a delicate house of
• 1:54
  Speaker 2: cards inside a tornado.
• 1:56
  Speaker 3: That's a perfect way to put it, honestly, because to
• 1:58
  Speaker 3: strip away those individual idea identities, you have to rob
• 2:01
  Speaker 3: the system of almost all its thermal energy, which is hard,
• 2:04
  Speaker 3: incredibly hard. I mean, traditionally that meant trapping a cloud
• 2:08
  Speaker 3: of atoms inside these massive, complex vacuum chambers, using a
• 2:12
  Speaker 3: raise of custom lasers to hold them in place, and
• 2:15
  Speaker 3: then chilling them down to roughly one hundred nanokelvin.
• 2:18
  Speaker 2: Which, just to put that in perspective for you, listening
• 2:21
  Speaker 2: is mere billions of a degree above absolute zero. I mean,
• 2:24
  Speaker 2: it is significantly colder than the deepest, darkest void of
• 2:28
  Speaker 2: outer space.
• 2:28
  Speaker 3: Yeah, it's truly extreme.
• 2:29
  Speaker 2: You're talking about facilities that take up entire rooms just
• 2:33
  Speaker 2: to make a microscopic puddle of this quantum fluid for
• 2:37
  Speaker 2: what a few.
• 2:37
  Speaker 3: Seconds exactly, And that extreme fragility is why this recent
• 2:42
  Speaker 3: breakthrough out of the Lawrence Berkeley National Laboratory is sending
• 2:45
  Speaker 3: shockwaves through the physics community.
• 2:47
  Speaker 2: Oh absolutely.
• 2:49
  Speaker 3: On August eleventh, twenty twenty six, researchers detailed how they
• 2:52
  Speaker 3: took this highly sensitive quantum phenomenon out of those isolated
• 2:56
  Speaker 3: room sized vacuums and they successfully created it inside a
• 3:00
  Speaker 3: solid semiconductor chip that is only a few atoms.
• 3:03
  Speaker 2: Thick, which is like finally having a calm, sturdy table
• 3:06
  Speaker 2: to build that house of cards one. So our mission
• 3:09
  Speaker 2: today is to figure out how they achieve the impossible.
• 3:12
  Speaker 2: We're going to explore the bizarre microscopic building blocks they
• 3:15
  Speaker 2: used instead of atoms, how they completely re engineered the
• 3:18
  Speaker 2: physical environment to make this quantum fluid stable, and how
• 3:21
  Speaker 2: they managed to give this fluid a switchable personality.
• 3:24
  Speaker 3: Basically, which is the coolest part.
• 3:25
  Speaker 2: Yeah, it is wild, and ultimately we'll see why putting
• 3:28
  Speaker 2: a quantum fluid onto a standard computer chip fundamentally changes
• 3:32
  Speaker 2: the timeline for future technology. So let's start with the
• 3:36
  Speaker 2: building blocks.
• 3:37
  Speaker 3: Right, because to appreciate the mechanics of what the Berkeley
• 3:39
  Speaker 3: team actually did, you can't easily use whole bulky atoms
• 3:44
  Speaker 3: like rubidium or helium.
• 3:46
  Speaker 2: Which is what those giant vacuum chambers use.
• 3:48
  Speaker 3: Right exactly. Instead, if you want this in a solid chip,
• 3:51
  Speaker 3: you have to use a composite particle that's native to
• 3:55
  Speaker 3: the semiconductor material itself. So they use something called an excitant.
• 3:59
  Speaker 2: Okay, let's slow down and look at the environment where
• 4:02
  Speaker 2: an excitement lives. Because the semiconductor isn't just empty space, no,
• 4:05
  Speaker 2: not at all. It's this densely packed crystal lattice. If
• 4:10
  Speaker 2: we zoom all the way in on the material inside,
• 4:12
  Speaker 2: you know, computer chip or a solar cell, we have
• 4:15
  Speaker 2: a rigid grid of atoms and all the electrons are
• 4:18
  Speaker 2: normally locked into their designated orbits.
• 4:20
  Speaker 3: Yeah, the material is effectively at rest. But if you
• 4:23
  Speaker 3: inject energy into that microscopic landscape. Let's say you shine
• 4:27
  Speaker 3: a specific wavelength of light onto the semiconductor, you can
• 4:30
  Speaker 3: hit one of those locked in electrons.
• 4:32
  Speaker 2: And it gets hyperactive, right exactly.
• 4:34
  Speaker 3: It absorbs the pocon's energy. It gets super hyperactive and
• 4:38
  Speaker 3: physically jumps out of its usual comfortable energy level into
• 4:41
  Speaker 3: a higher one where it's free to roam around the crystal.
• 4:44
  Speaker 2: And because it jumped out, it leaves behind an empty
• 4:47
  Speaker 2: parking spot basically in the atomic grid.
• 4:50
  Speaker 3: Yes, that empty parking spot is a foundational concept in
• 4:54
  Speaker 3: solid state physics. We call it a hole a hole, right,
• 4:58
  Speaker 3: and it's far more than just empty space. Because an
• 5:01
  Speaker 3: electron carries a negative charge, the space that just vacated
• 5:05
  Speaker 3: is now missing a negative charge.
• 5:07
  Speaker 2: So relative to the rest of the neutral crystal lattice,
• 5:11
  Speaker 2: that empty space effectively acts as a positive charge exactly.
• 5:15
  Speaker 3: You know.
• 5:15
  Speaker 2: I always think of it like an air bubble and
• 5:17
  Speaker 2: a carpenter's level. The bubble isn't really a distinct physical object, right,
• 5:21
  Speaker 2: It's just the absence of liquid.
• 5:23
  Speaker 3: Oh, that's a good analogy, yep.
• 5:25
  Speaker 2: But as you tilt the level, the bubble moves around
• 5:28
  Speaker 2: and interacts with its environment as if it were a
• 5:30
  Speaker 2: solid independent thing.
• 5:32
  Speaker 3: That is a highly accurate way to visualize it. The
• 5:34
  Speaker 3: hole can move through the lattice as neighboring electrons slide
• 5:37
  Speaker 3: over to fill it, pushing that empty space down the line.
• 5:41
  Speaker 3: So now you have a negatively charged electron zipping around,
• 5:45
  Speaker 3: and a positively charged hole moving around as well. And
• 5:48
  Speaker 3: because fundamental physics dictates that opposites attract, the electron and
• 5:53
  Speaker 3: the hole feel this really strong electrostatic pull toward one another.
• 5:57
  Speaker 2: They don't just ignore each other in the crystal. They
• 5:59
  Speaker 2: find each other.
• 6:00
  Speaker 3: They absolutely do. They orbit a common center of mass,
• 6:04
  Speaker 3: bound together by that attraction, acting almost exactly like a
• 6:07
  Speaker 3: tiny artificial hydrogen atom.
• 6:10
  Speaker 2: Wow.
• 6:10
  Speaker 3: And that pairing the electron and the whole dancing around
• 6:13
  Speaker 3: each other is an excitant. And because an excitant is
• 6:16
  Speaker 3: composed of two particles that each have a half integer spin,
• 6:20
  Speaker 3: their combined spin becomes a whole integer, which classifies the
• 6:24
  Speaker 3: excitant as a boson.
• 6:25
  Speaker 2: Which is like the magic word for quantum physicists. It
• 6:28
  Speaker 2: really is, because bosons are the only types of particles
• 6:31
  Speaker 2: that can share the exact same quantum state. Right, if
• 6:33
  Speaker 2: you get enough excitance together, and you get them cold enough,
• 6:36
  Speaker 2: they won't clash or pump into each other.
• 6:38
  Speaker 3: Right, they will theoretically sync up into that single coherent
• 6:41
  Speaker 3: quantum fluid we mentioned earlier, the Bose Einstein condensate.
• 6:45
  Speaker 2: So okay, The theoretical math proved decades ago that an
• 6:50
  Speaker 2: excite and BC was possible. What was the roadblock the.
• 6:54
  Speaker 3: Physical life span of the excite in itself.
• 6:57
  Speaker 2: Ah.
• 6:57
  Speaker 3: Yeah, when you create them by shining light on them
• 7:00
  Speaker 3: material you are creating a highly energized, unstable state. And
• 7:04
  Speaker 3: nature always prefers to be lazy. You know, it wants
• 7:08
  Speaker 3: to return to the lowest possible energy state.
• 7:10
  Speaker 2: The electron wants its barking spot back.
• 7:12
  Speaker 3: It aggressively seeks it out. Usually within a fraction of
• 7:16
  Speaker 3: a nanosecond, literally a billionth of a second, the electron
• 7:19
  Speaker 3: loses its extra energy, falls back into the hole, and
• 7:22
  Speaker 3: annihilates the excitement, releasing a tiny flash of light.
• 7:25
  Speaker 2: Wait, so if this particle is basically a temporary dance
• 7:28
  Speaker 2: partner where one person's an electron and the other is
• 7:30
  Speaker 2: literally the absence of an electron, how do you get
• 7:33
  Speaker 2: them to form a stable fluid?
• 7:34
  Speaker 3: Yeah, that's the million dollar question, because.
• 7:36
  Speaker 2: If the dance ends in a billionth of a second,
• 7:38
  Speaker 2: you don't have a fluid. I mean, you just have
• 7:40
  Speaker 2: a chaotic flash of sparks.
• 7:42
  Speaker 3: You have hit the exact wall that stopped physicists for years.
• 7:47
  Speaker 3: A billionth of a second is just not nearly enough
• 7:50
  Speaker 3: time for a collection of excitance to bump into each other,
• 7:54
  Speaker 3: share their thermal energy, cool down, and reach the collective
• 7:58
  Speaker 3: thermal equilibrium required to a condency. They just vanish, right,
• 8:02
  Speaker 3: The particles just vanished before they can even get to
• 8:04
  Speaker 3: know each other.
• 8:05
  Speaker 2: So you can't just shine a brighter laser on the
• 8:07
  Speaker 2: chip and hope to overwhelm the system with excitement.
• 8:10
  Speaker 3: Oh no, that wouldn't work.
• 8:11
  Speaker 2: You have to somehow stop the electron from crashing back
• 8:14
  Speaker 2: into the hole without breaking the attraction that keeps them
• 8:17
  Speaker 2: bound together. How on earth do you put a physical
• 8:20
  Speaker 2: barrier between an electron and a microscopic hole in a crystal.
• 8:24
  Speaker 3: You have to fundamentally re engineer the crystal itself. So
• 8:27
  Speaker 3: the Berkeley Lab team solve this by moving away from
• 8:30
  Speaker 3: a single chunk of semiconductor, and they built this custom heterostructure. Okay,
• 8:34
  Speaker 3: they took two distinct types of two dimensional semiconductor's materials
• 8:39
  Speaker 3: that are literally only a single atom thick and stack
• 8:42
  Speaker 3: them on top of each other like a microscopic sandwich,
• 8:44
  Speaker 3: an incredibly precise one.
• 8:46
  Speaker 2: Yeah.
• 8:46
  Speaker 3: Because the two layers are made of different elements, their
• 8:49
  Speaker 3: internal energy landscapes don't perfectly align. Interesting the physics of
• 8:54
  Speaker 3: this specific pairing creates a situation where the electron vastly
• 8:58
  Speaker 3: prefers the energy environment of one layer, while the positive
• 9:02
  Speaker 3: hole strongly prefers the energy environment of the other layer.
• 9:05
  Speaker 2: Okay, let me make sure I'm wrapping my head around
• 9:07
  Speaker 2: this mechanism. It's almost like a multi level parking garage
• 9:13
  Speaker 2: with a really specialized elevator.
• 9:15
  Speaker 3: Okay, I'm with you.
• 9:16
  Speaker 2: So the electron absorbs energy and goes up to the
• 9:19
  Speaker 2: second floor, leaving the hole on the first floor. But
• 9:22
  Speaker 2: because of the specific materials they chose, the electron can't
• 9:25
  Speaker 2: easily ride the elevator back down, so it's stuck in
• 9:28
  Speaker 2: the upper layer and the hole is stuck in the
• 9:30
  Speaker 2: lower layer.
• 9:30
  Speaker 3: Yes, the atomic structure of the materials creates a physical
• 9:34
  Speaker 3: and energetic wall between them. The electron and the hole
• 9:37
  Speaker 3: are physically separated by the gap between the two two
• 9:40
  Speaker 3: D layers. However, that gap is so incredibly thin, just
• 9:44
  Speaker 3: fractions of an animeter, that the electrostatic attraction between the
• 9:47
  Speaker 3: positive and negative charges reaches right through the barrier.
• 9:50
  Speaker 2: So they are forced to stay in separate lanes. But
• 9:53
  Speaker 2: they are so close they still bind together and move
• 9:56
  Speaker 2: as a single unit across.
• 9:57
  Speaker 3: The chip exactly physicists call a spatially indirect excitan. And
• 10:03
  Speaker 3: the consequence of this clever engineering is monumental because the
• 10:07
  Speaker 3: electron is physically blocked from easily recombining with the whole
• 10:11
  Speaker 3: the lifespan of the exciting skyrockets.
• 10:14
  Speaker 2: Wow.
• 10:14
  Speaker 3: More importantly, this stacked structure alters what we call the
• 10:18
  Speaker 3: ground state.
• 10:19
  Speaker 2: Of the system, the lazy state.
• 10:21
  Speaker 3: Right in a normal material, the lowest, laziest energy state,
• 10:25
  Speaker 3: the ground state has zero.
• 10:26
  Speaker 2: Exciting because you have to add energy to make them.
• 10:29
  Speaker 3: But in this artificially engineered lattice, under the right conditions,
• 10:32
  Speaker 3: the lowest energy state actually contains these permanent indirect excitans.
• 10:36
  Speaker 2: Oh that's wild.
• 10:37
  Speaker 3: They become a natural, stable feature of the material's resting state.
• 10:41
  Speaker 3: They don't vanish in a billionth of a second, which
• 10:44
  Speaker 3: gives them plenty of time to interact, cool down, and
• 10:47
  Speaker 3: seamlessly merge into a stable Bose Einstein condensate.
• 10:51
  Speaker 2: That is just an elegant piece of manipulation. I mean,
• 10:53
  Speaker 2: they didn't fight the short lifespan, They just bypassed it
• 10:56
  Speaker 2: by changing the architectural rules of the environment itself.
• 11:00
  Speaker 3: It really is brilliant.
• 11:00
  Speaker 2: But you know, bridging that gap brings up the temperature
• 11:04
  Speaker 2: milestone of this which is a massive part of why
• 11:06
  Speaker 2: this is such a huge breakthrough. Once they engineer this
• 11:10
  Speaker 2: stable excite and fluid, they realized it remained coherent up
• 11:13
  Speaker 2: to about two kelvin.
• 11:15
  Speaker 3: Which represents a staggering paradigm shift for quantum physics.
• 11:19
  Speaker 2: Okay, I have to push back a little here because
• 11:20
  Speaker 2: to anyone listening, two kelvin is roughly minus four hundred
• 11:24
  Speaker 2: and fifty six degrees fahrenheit. Yeah, that still sounds like
• 11:28
  Speaker 2: an incredibly prohibitive, unimaginably freezing environment. You know why is
• 11:33
  Speaker 2: the scientific community popping champagne over to kelvin?
• 11:37
  Speaker 3: The celebration is really about the practical infrastructure required to
• 11:40
  Speaker 3: reach that temperature. When we talked about the traditional atomic
• 11:43
  Speaker 3: BECs earlier, they required temperatures around one hundred nanokelvin. Two
• 11:47
  Speaker 3: kelvin is approximately twenty million times warmer.
• 11:50
  Speaker 2: Than that twenty million times warmer.
• 11:51
  Speaker 3: Yeah. To get to nanokelvin temperatures, you need lasers meticulously
• 11:56
  Speaker 3: tuned to slow down individual atoms, massive magnetic coils to
• 12:00
  Speaker 3: trap them, and ultra high vacuums to prevent any ambient
• 12:04
  Speaker 3: molecules from destroying the condency.
• 12:06
  Speaker 2: Just massive setups.
• 12:08
  Speaker 3: Only highly specialized, really well funded national labs can maintain
• 12:12
  Speaker 3: that kind of equipment.
• 12:13
  Speaker 2: It's basically the spoke.
• 12:14
  Speaker 3: Physics exactly, but two calvin crosses a critical threshold that
• 12:18
  Speaker 3: is a temperature you can achieve using liquid helium in
• 12:21
  Speaker 3: a standard piece of laboratory equipment called a cryostat. Okay,
• 12:24
  Speaker 3: and liquid helium cooling is a ubiquitous technology. It's used
• 12:28
  Speaker 3: in MRI machines at hospitals, It's used in thousands of
• 12:31
  Speaker 3: university chemistry and physics labs all around the world.
• 12:34
  Speaker 2: So by moving the required temperature from one hundred nanocalvin
• 12:37
  Speaker 2: up to two kelvin, you take this phenomenon out of
• 12:40
  Speaker 2: the exclusive realm of room sized quantum physics labs and
• 12:44
  Speaker 2: you drop it right onto the work bench of thousands
• 12:46
  Speaker 2: of materials scientists and electrical engineers. You make a quantum
• 12:49
  Speaker 2: fluid accessible.
• 12:51
  Speaker 3: And accessibility accelerates discovery. Because the fluid was sitting stably
• 12:56
  Speaker 3: inside a microchip inside a standard cryostat, the Berkeley team,
• 13:00
  Speaker 3: led by principal investigator Feng Wang could finally start poking
• 13:04
  Speaker 3: and prodding at it in ways that are just impossible
• 13:07
  Speaker 3: in a fragile vacuum crap, right, and that is when
• 13:10
  Speaker 3: they discovered this fluid possesses a highly complex hidden internal structure.
• 13:15
  Speaker 2: Okay, so to see this hidden structure, they used a
• 13:18
  Speaker 2: technique called magneto optical spectroscopy. But before we get into
• 13:22
  Speaker 2: what they found, let's establish how they actually interact with
• 13:24
  Speaker 2: the fluid, Like, how are they looking at it?
• 13:26
  Speaker 3: Well, magneto optical spectroscopy sounds intimidating, but the core mechanism
• 13:30
  Speaker 3: is quite logical. Optical means they are interacting with the
• 13:33
  Speaker 3: chip using light.
• 13:34
  Speaker 2: Okay.
• 13:35
  Speaker 3: They shine a highly specific tunable laser onto the semiconductor.
• 13:39
  Speaker 3: Because excitants are literally born from light and a mid light.
• 13:42
  Speaker 3: When they decay, they are incredibly sensitive to the laser.
• 13:45
  Speaker 2: Makes sense.
• 13:46
  Speaker 3: By analyzing exactly which colors of light the chip absorbs
• 13:49
  Speaker 3: or reflects, the researchers can read the precise energy state
• 13:52
  Speaker 3: and density of the quantum fluid.
• 13:54
  Speaker 2: So the light basically acts as a probe. But it's
• 13:57
  Speaker 2: not just a passive observation, right, Because the hip is
• 14:00
  Speaker 2: wired up. They are applying electrical voltages while they shine
• 14:03
  Speaker 2: the light.
• 14:04
  Speaker 3: Yes, and the electrical control is what makes this a
• 14:06
  Speaker 3: true device rather than just a passive experiment. The chip
• 14:10
  Speaker 3: has electrical gates built right into it. By simply turning
• 14:14
  Speaker 3: a dial and changing the voltage on those gates, the
• 14:17
  Speaker 3: team can inject more electrons or holes into the active layers.
• 14:22
  Speaker 3: They have direct real time control over the density of
• 14:26
  Speaker 3: the excitments.
• 14:26
  Speaker 2: So they can dial the crowd size of the quantum
• 14:29
  Speaker 2: fluid up or down with a voltage knob, like using
• 14:32
  Speaker 2: a dimmer switch on the light bulb.
• 14:33
  Speaker 3: Exactly a lever of control that researchers working with atomic
• 14:37
  Speaker 3: BECs and vacuums would absolutely envy, for sure. But the
• 14:40
  Speaker 3: magneto part of magneto optical spectroscopy is where the internal
• 14:44
  Speaker 3: structure really reveals itself. They apply a strong magnetic field
• 14:48
  Speaker 3: perpendicular to the chip.
• 14:50
  Speaker 2: Okay, but to understand why the magnetic field does anything
• 14:53
  Speaker 2: at all, we have to look closely at the properties
• 14:55
  Speaker 2: of the electrons and holes in these specific twty crystals.
• 14:58
  Speaker 3: Right.
• 14:58
  Speaker 2: Because normally we just think of particles is having a
• 15:01
  Speaker 2: charge and maybe a spin like a tiny internal compass.
• 15:05
  Speaker 2: Pointing either up or down.
• 15:06
  Speaker 3: Spin is critical, But in these ultra thin hexagonal crystal lattices,
• 15:12
  Speaker 3: the particles have an additional property known as a valley
• 15:15
  Speaker 3: degree of freedom.
• 15:16
  Speaker 2: Now, this is where things get slightly abstract. What is
• 15:20
  Speaker 2: a valley in a crystal? It's not a physical dent
• 15:23
  Speaker 2: in the surface, right, It is not a physical dent.
• 15:25
  Speaker 3: No, It refers to the momentum space of the crystal.
• 15:28
  Speaker 3: As an electron moves through the repeating grid of atoms,
• 15:32
  Speaker 3: the energy landscape it experiences isn't completely flat. It undulates.
• 15:36
  Speaker 2: Okay, there are.
• 15:37
  Speaker 3: Specific energy minimums, local dips in the energy band structure
• 15:41
  Speaker 3: where the electron naturally prefers to settle. These dips are
• 15:44
  Speaker 3: the valleys.
• 15:45
  Speaker 2: So if the electron is a ball rolling across a
• 15:48
  Speaker 2: slightly bumpy terrain, it's naturally going to settle into one
• 15:51
  Speaker 2: of the grooves. And in these specific materials, there are
• 15:54
  Speaker 2: two distinct, equivalent grooves that can settle into.
• 15:57
  Speaker 3: Precisely the particle can exis in valley K or valley
• 16:02
  Speaker 3: K prime. Now, when you combine the particle's spin, which
• 16:06
  Speaker 3: can be up or down, with this specific valley it occupies,
• 16:09
  Speaker 3: you get unique combinations. The physics community refers to these
• 16:13
  Speaker 3: specific combinations of spin and valley as.
• 16:16
  Speaker 2: Different flavors, Meaning an excitement isn't just a generic particle,
• 16:19
  Speaker 2: its specific internal alignment, its spin, and its valley position
• 16:25
  Speaker 2: gives it a distinct flavor exactly.
• 16:28
  Speaker 3: And what Fang Wang's team observed through their optical probing
• 16:31
  Speaker 3: was that their Bose Einstein condensate wasn't just a uniform,
• 16:34
  Speaker 3: featureless fluid of a single flavor.
• 16:36
  Speaker 2: Wow.
• 16:37
  Speaker 3: It naturally settled into a highly ordered state containing two
• 16:40
  Speaker 3: distinct components. The fluid possessed a complex internal character like
• 16:45
  Speaker 3: a mixture of spin, valley alignment.
• 16:46
  Speaker 2: So it's a fluid with a structured identity. And this
• 16:48
  Speaker 2: is where the magnetic field comes in right. Because magnetic
• 16:50
  Speaker 2: field interacts with the spin of.
• 16:52
  Speaker 3: Particles, the magnetic field exerts a torque on both the
• 16:54
  Speaker 3: spin and the valley magnetic moments of the excitance. When
• 16:57
  Speaker 3: they ramped up the magnetic field, they slid stress to
• 17:00
  Speaker 3: that internal structure. What happened at a certain threshold, the
• 17:04
  Speaker 3: energy required to maintain the original flavor mixture became too high,
• 17:08
  Speaker 3: and the entire quantum fluid snapped into a new alignment.
• 17:12
  Speaker 2: They literally forced the excitements to flip their spins and
• 17:15
  Speaker 2: shift balleys.
• 17:16
  Speaker 3: They forced a macroscopic quantum phase transition by turning a
• 17:20
  Speaker 3: magnetic knob. They completely rerote the internal spin valley order
• 17:24
  Speaker 3: of the fluid on demand.
• 17:26
  Speaker 2: That is just I mean to ground this in an analogy,
• 17:29
  Speaker 2: Imagine looking down at a massive football stadium where every
• 17:32
  Speaker 2: single person in the crowd is holding up a red
• 17:35
  Speaker 2: flash card. Right from a distance, the stadium looks entirely red.
• 17:38
  Speaker 2: It's a single uniform state. But the moment you flip
• 17:42
  Speaker 2: a magnetic switch, every person in the stadium instantly flips
• 17:45
  Speaker 2: their card to blue. Exactly, you haven't changed the physical
• 17:48
  Speaker 2: substance of the crowd, like they're all still in their seats.
• 17:50
  Speaker 2: It hasn't turned from syrup to glass. But you have
• 17:53
  Speaker 2: fundamentally instantly altered the internal structural state of the entire system.
• 17:58
  Speaker 3: That is a phenomenal way to visualize it. You are
• 18:00
  Speaker 3: commanding a macroscopic quantum state to reorganize its internal.
• 18:05
  Speaker 2: Architecture, which is mind blowing.
• 18:06
  Speaker 3: Prior to this, researchers couldn't definitively prove that excitance had
• 18:11
  Speaker 3: condensed in these structures, let alone observe or manipulate their
• 18:14
  Speaker 3: internal order like that. The Berkeley team didn't just create
• 18:18
  Speaker 3: the fluid, They found a way to steer.
• 18:20
  Speaker 2: It and the leap from abstract chalkboard physics to actual
• 18:25
  Speaker 2: tunable engineering here is profound. I mean, if you can
• 18:29
  Speaker 2: electrically control the density and magnetically flip the internal state
• 18:34
  Speaker 2: of a quantum fluid sitting on a solid chip, the
• 18:37
  Speaker 2: applications move far beyond just writing a fascinating paper. Absolutely,
• 18:41
  Speaker 2: where does this technology actually go?
• 18:43
  Speaker 3: Well, the implications branch into several major fields of physics
• 18:46
  Speaker 3: and engineering. Starting with optoelectronics, we established that excitants are
• 18:50
  Speaker 3: inherently coupled to light. Because this condensate acts as a
• 18:54
  Speaker 3: single coherent quantum state, it emits light coherently when the
• 18:58
  Speaker 3: excitans do eventually reco So.
• 19:00
  Speaker 2: It's essentially a blueprint for a completely new type of laser.
• 19:04
  Speaker 3: Lasers that operate at incredibly low power thresholds compared to
• 19:07
  Speaker 3: what we use today. Or consider optical switches and sensors.
• 19:10
  Speaker 2: Oh yeah, If the.
• 19:11
  Speaker 3: Internal state of the fluid can be flipped instantly and
• 19:14
  Speaker 3: that fluid interacts directly with light, you have the foundation
• 19:18
  Speaker 3: for ultra fast, highly sensitive components that translate quantum information
• 19:23
  Speaker 3: directly into optical signals.
• 19:26
  Speaker 2: Which naturally leads to how that information moves around the chip. Yeah,
• 19:29
  Speaker 2: because The defining characteristic of a Bose Einstein condensate is
• 19:33
  Speaker 2: that it can behave as a superfluid.
• 19:35
  Speaker 3: Yes, a true superfluid flows with zero viscosity, meaning it
• 19:39
  Speaker 3: experiences absolutely no friction.
• 19:41
  Speaker 2: Zero friction.
• 19:43
  Speaker 3: Now, moving an excite and superfluid isn't exactly the same
• 19:46
  Speaker 3: as moving an electrical current, because excitants are electrically neutral overall,
• 19:50
  Speaker 3: the positive and negative charges cancel each other out. But
• 19:53
  Speaker 3: they do carry energy and they can carry spin or
• 19:56
  Speaker 3: valley information.
• 19:57
  Speaker 2: So if you can push a wave of this excite
• 19:59
  Speaker 2: and fluid from one side of a processor to the other,
• 20:02
  Speaker 2: it carries that information without bouncing off the atoms in
• 20:05
  Speaker 2: the crystal lattice. It moves without friction, meaning it doesn't
• 20:08
  Speaker 2: generate heat. I mean, we spend massive amounts of energy
• 20:12
  Speaker 2: just cooling down data centers because moving electrons through copper
• 20:17
  Speaker 2: creates so much resistance. A superfluid data bus would be
• 20:20
  Speaker 2: revolutionary completely.
• 20:22
  Speaker 3: And while engineers work towards those commercial applications, physicists gain
• 20:26
  Speaker 3: an immediate, powerful tool for quantum simulation.
• 20:30
  Speaker 2: Right, I didn't even think about that. Yeah.
• 20:32
  Speaker 3: Many of the most profound mysteries in physics, like the
• 20:35
  Speaker 3: mechanics of high temperature superconductors or the behavior of really
• 20:38
  Speaker 3: exotic particles are incredibly difficult to model on classical computers
• 20:43
  Speaker 3: because the quantum math scales exponentially.
• 20:46
  Speaker 2: But now you don't have to model it on the computer.
• 20:48
  Speaker 2: You literally have a physical quantum fluid sitting on a
• 20:51
  Speaker 2: desk that you can tune and tweak.
• 20:54
  Speaker 3: You can map the parameters of an unsolved physics problem
• 20:56
  Speaker 3: onto the tunable parameters of the excite and fluid. You
• 20:59
  Speaker 3: can use the chip as an analog simulator to watch
• 21:02
  Speaker 3: how the quantum rules play out in real time.
• 21:04
  Speaker 2: It's an unprecedented playground, and it is really vital to
• 21:08
  Speaker 2: acknowledge the scale of the effort required to build it.
• 21:11
  Speaker 2: This wasn't just a few people tinkering in a basement,
• 21:13
  Speaker 2: definitely not. It was a massive collaboration involving UC Berkeley,
• 21:17
  Speaker 2: the University of Texas at Austin, the National Institute from
• 21:20
  Speaker 2: Material Science in Japan, heavily backed by the US Department
• 21:24
  Speaker 2: of Energy. Pushing the absolute limits of materials. Science like
• 21:28
  Speaker 2: this requires a global infrastructure.
• 21:30
  Speaker 3: It requires a synthesis of perfect crystal growth, extreme cryogenic engineering,
• 21:36
  Speaker 3: and advanced optical measurement. They took one of the most
• 21:39
  Speaker 3: fragile states of matter in the universe and anchored it
• 21:42
  Speaker 3: to a solid state device.
• 21:44
  Speaker 2: We took a phenomenon that used to demand room sized
• 21:47
  Speaker 2: vacuum chambers and temperatures colder than deep space, and we
• 21:50
  Speaker 2: trapped it in a microscopic sandwich. We didn't just capture
• 21:53
  Speaker 2: a quantum fluid. We gave it a steering wheel, a transmission,
• 21:57
  Speaker 2: and the ability to interact with the physical world on
• 21:59
  Speaker 2: our turn.
• 22:00
  Speaker 3: It is the definitive bridge between quantum physics and tangible technology.
• 22:05
  Speaker 3: We now have a platform where the weirdness of quantum
• 22:07
  Speaker 3: mechanics can actually be harnessed as an engineering resource, which breaks.
• 22:10
  Speaker 2: Up a really fascinating question for the road ahead. You know,
• 22:13
  Speaker 2: we talked about how this team brought the operating temperature
• 22:16
  Speaker 2: up by a factor of twenty million, reaching two kelvin.
• 22:19
  Speaker 2: The Holy Grail naturally is pushing that temperature higher, perhaps
• 22:24
  Speaker 2: one day maintaining these macroscopic quantum states at room temperature
• 22:28
  Speaker 2: inside solid state chips. But w aren't you to look
• 22:30
  Speaker 2: beyond just the idea of laptops that don't get hot?
• 22:33
  Speaker 2: Oh definitely, if we can stabilize a state of matter
• 22:36
  Speaker 2: where millions of particles lose their individual identities and act
• 22:39
  Speaker 2: as a single, coherent quantum entity, and we can embed
• 22:44
  Speaker 2: that entity into a solid matrix. What happens when we
• 22:47
  Speaker 2: start scaling that up. We've spent decades building computer chips
• 22:51
  Speaker 2: that process information linearly right, moving distinct electrons from point
• 22:55
  Speaker 2: A to point B like traffic on a highway.
• 22:57
  Speaker 3: Yep, classical computing, but.
• 22:58
  Speaker 2: A quantum fluid doesn't have it experiences the entire chip simultaneously.
• 23:03
  Speaker 2: Imagine a future where we move away from traditional computing
• 23:06
  Speaker 2: entirely and instead design synthetic, macroscopic quantum materials that process
• 23:11
  Speaker 2: complex information inherently simply by shifting their internal quantum geometry.
• 23:15
  Speaker 3: It's a completely different paradigm.
• 23:16
  Speaker 2: We may not be looking at the next generation of microchips.
• 23:20
  Speaker 2: We might be looking at the earliest prototypes of materials
• 23:23
  Speaker 2: that fundamentally think in a language we are only just
• 23:26
  Speaker 2: beginning to decipher. Thank you so much for joining us
• 23:30
  Speaker 2: for this journey into the bleeding edge of quantum physics.
• 23:32
  Speaker 2: We appreciate your curiosity, your time, and as always, keep
• 23:35
  Speaker 2: asking the big questions.