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How Ultracold Atoms Are Unlocking the Quantum World · The Quark Side - Quantum Physics Podcast

• 0:01
  Speaker 1: Welcome to the qure 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 of the smallest scales.
• 0:27
  Speaker 2: So if you were to try and find the absolute
• 0:32
  Speaker 2: the absolute coldest place in the entire universe, where would
• 0:35
  Speaker 2: you even go?
• 0:36
  Speaker 3: Well, I think most people would probably picture heading out
• 0:38
  Speaker 3: in the spaceship right, Yeah.
• 0:40
  Speaker 2: Like venturing into the deepest, darkest void of interstellar space.
• 0:43
  Speaker 3: Exactly light years away from any warming.
• 0:45
  Speaker 2: Star, right, And I mean, deep space is incredibly cold.
• 0:49
  Speaker 2: It hovers just a few degrees above absolute zero. But
• 0:53
  Speaker 2: the crazy thing is the actual coldest places in existence,
• 0:59
  Speaker 2: the location where temperature practically ceases to exist. They aren't
• 1:03
  Speaker 2: in space at all, No, they really are. They're sitting
• 1:05
  Speaker 2: on laboratory benches right here on Earth.
• 1:08
  Speaker 3: Yeah, it's the irony is just brilliant, honestly, it really is.
• 1:11
  Speaker 2: So we're gonna explore the mind bending frontier of ultra
• 1:14
  Speaker 2: cold atoms. We need to figure out how scientists are
• 1:16
  Speaker 2: successfully freezing matter down to like a billionth of a
• 1:19
  Speaker 2: degree and why this bizarre super chilled realm is basically
• 1:24
  Speaker 2: the key to unlocking the next massive leap in human technology.
• 1:27
  Speaker 3: Right, because we live on this geologically active warm rock,
• 1:30
  Speaker 3: you know, orbiting a massive nuclear furnace of a sun.
• 1:33
  Speaker 2: Yeah, a very hot neighborhood exactly.
• 1:36
  Speaker 3: Yet human beings have somehow engineered localized pockets of space
• 1:40
  Speaker 3: that are billions of times colder than the vacuum of the.
• 1:43
  Speaker 2: Cosmos billions of times. That is just staggering.
• 1:47
  Speaker 3: And we aren't doing this just to break temperature records either.
• 1:49
  Speaker 3: When you push matter to these extreme limits, the familiar
• 1:54
  Speaker 3: everyday rules of classical physics just they could completely melt away.
• 1:58
  Speaker 2: They just stop working basically.
• 2:00
  Speaker 3: Yeah, Adams stop acting like little solid billiard balls. They
• 2:04
  Speaker 3: start dancing in this perfect quantum harmony, which actually allows
• 2:07
  Speaker 3: us to observe the fundamental laws of nature with our
• 2:10
  Speaker 3: own naked eyes.
• 2:12
  Speaker 2: Okay, let's impact this, because my brain immediately goes to
• 2:15
  Speaker 2: you every day cooling.
• 2:17
  Speaker 3: Sure, like your kitchen fridge.
• 2:18
  Speaker 2: Right, If I want to cool something down, I put
• 2:20
  Speaker 2: in the fridge, I surround it with something colder. But
• 2:22
  Speaker 2: you can't exactly take an individual atom and put it
• 2:24
  Speaker 2: in a microscopic freezer.
• 2:26
  Speaker 3: No, you definitely can't do that.
• 2:27
  Speaker 2: So how do scientists actually pull this off?
• 2:29
  Speaker 3: Well they use lasers. Lasers, yeah, which I know sounds
• 2:32
  Speaker 3: like a total contradiction.
• 2:33
  Speaker 2: It sounds like madness. I mean, in every sci fi
• 2:36
  Speaker 2: movie and just in everyday industrial life, lasers heat things.
• 2:40
  Speaker 3: At right, They burn right through metal exactly.
• 2:42
  Speaker 2: So shining a high intensity laser at an atom to
• 2:46
  Speaker 2: cool it down it feels like trying to put out
• 2:48
  Speaker 2: a house fire with a flamethrower.
• 2:50
  Speaker 3: It is deeply counterinto it, if I'll give you that.
• 2:53
  Speaker 3: But this technique, which was actually pioneered back in the
• 2:56
  Speaker 3: nineteen seventies and nineteen eighties, it relies on a phenomenon
• 2:59
  Speaker 3: called the Doppler cooling effect.
• 3:01
  Speaker 2: Okay, Doppler cooling.
• 3:03
  Speaker 3: Yeah. And to understand it, we kind of have to
• 3:05
  Speaker 3: remember what temperature actually is in the first place.
• 3:07
  Speaker 2: Right, It's not just a feeling on your skin exactly.
• 3:09
  Speaker 3: Temperature isn't some mystical property. It's really just a measurement
• 3:13
  Speaker 3: of motion. It's the chaotic, jittery vibrating of molecules.
• 3:17
  Speaker 2: So the hot or something is the faster its atoms
• 3:20
  Speaker 2: are bouncing around.
• 3:21
  Speaker 3: Spot on. So now think of laser light not as
• 3:24
  Speaker 3: a continuous beam, but as a rapid fire stream of
• 3:27
  Speaker 3: individual particles like photons, right, a stream of photons, Yeah,
• 3:31
  Speaker 3: and each of those photons carries a minuscule mini momentum.
• 3:34
  Speaker 2: Just a tiny physical push.
• 3:36
  Speaker 3: Yeah. So if an atom absorbs a photon, it absorbs
• 3:39
  Speaker 3: that momentum. Imagine an atom moving toward a laser beam,
• 3:43
  Speaker 3: it gets hit by a photon, absorbs it, and gets
• 3:45
  Speaker 3: his microscopic kick in the opposite direction.
• 3:47
  Speaker 2: Oh, I see. It's It's like trying to stop a
• 3:50
  Speaker 2: rolling bowling ball by pelting it with a rapid fire
• 3:53
  Speaker 2: stream of ping pong balls.
• 3:55
  Speaker 3: That is a perfect analogy. One pingpong ball isn't going
• 3:58
  Speaker 3: to stop the bowling ball, right, wouldn't even But if
• 4:01
  Speaker 3: you hit it with millions of ping pong balls every
• 4:03
  Speaker 3: single second, eventually that bowling ball is going to grind
• 4:06
  Speaker 3: to a halt.
• 4:07
  Speaker 2: And because temperature is just velocity slowing down the atom
• 4:11
  Speaker 2: means you.
• 4:11
  Speaker 3: Are cooling it down exactly. But the trick, though, is
• 4:14
  Speaker 3: making sure the ping pong balls only hit the bowling
• 4:17
  Speaker 3: ball when it's rolling towards you.
• 4:19
  Speaker 2: Oh, because if they hit it from behind.
• 4:21
  Speaker 3: They'd speed it up, they would make it hotter.
• 4:23
  Speaker 2: Ah, right, that would defeat the whole purpose.
• 4:26
  Speaker 3: Yeah, So physicists solve this using the Doppler effect. They
• 4:30
  Speaker 3: tune the color of the laser light so its frequency
• 4:33
  Speaker 3: is just slightly below the atom's natural resonance.
• 4:35
  Speaker 2: What does that mean in practice?
• 4:37
  Speaker 3: It means that at this specific frequency, a stationary atom
• 4:41
  Speaker 3: won't absorb the light at all. The light just passes
• 4:44
  Speaker 3: right through it. Okay, so it ignores the laser if
• 4:46
  Speaker 3: it's sitting still, right. But if the atom is rushing
• 4:49
  Speaker 3: head on toward the laser, the lightwaves get compressed from
• 4:52
  Speaker 3: the atom's perspective, like a.
• 4:54
  Speaker 2: Police siren sounding higher as it drives towards you.
• 4:56
  Speaker 3: Exactly, the color effectively shifts upward, hitting the perfect frequency,
• 5:01
  Speaker 3: and the atom absorbs the photon, slamming on the brakes.
• 5:04
  Speaker 2: Wow. So the atom is essentially selectively choosing to only
• 5:09
  Speaker 2: absorb the light that slows it down.
• 5:10
  Speaker 3: Yes, And by firing these perfectly tuned lasers from all
• 5:15
  Speaker 3: six directions up, down, less, right, forward, backward, the atom
• 5:19
  Speaker 3: gets constantly kicked back towards the center. No matter which
• 5:22
  Speaker 3: way it tries to dart, it's just trapped, completely trapped.
• 5:25
  Speaker 3: It enters this sluggish state that physicists affectionately call optical
• 5:29
  Speaker 3: molasses optical molasses.
• 5:31
  Speaker 2: I love that.
• 5:32
  Speaker 3: It's very descriptive. And the scientists who perfected this Stephen Chew,
• 5:36
  Speaker 3: Claude Cohen Tanuji, and William Phillips. They actually won the
• 5:39
  Speaker 3: nineteen ninety seven Nobel Prize for it.
• 5:41
  Speaker 2: Okay, so the ping pine balls trapped the bowling ball.
• 5:44
  Speaker 2: It's stuck in the molasses. But you mentioned earlier we
• 5:47
  Speaker 2: need to reach a billionth of.
• 5:49
  Speaker 3: A degree, Yes, the nano kelvin range.
• 5:51
  Speaker 2: Right, does laser cooling actually get us all the way
• 5:54
  Speaker 2: down to that absolute floor? Or do we hit some
• 5:57
  Speaker 2: kind of wall because it feels like constantly pelting something
• 6:00
  Speaker 2: with photons would eventually cause its own kind of I
• 6:03
  Speaker 2: don't know, jittering.
• 6:04
  Speaker 3: You hit a very strict wall. Actually, the random emission
• 6:07
  Speaker 3: of the photons causes a tiny quantum recoil, so it
• 6:11
  Speaker 3: does jitter.
• 6:12
  Speaker 2: So how do you get past that?
• 6:13
  Speaker 3: To push past that limit and reach the nanokelvin realm
• 6:16
  Speaker 3: physicists just turn off the lasers completely.
• 6:19
  Speaker 2: They just shut them off.
• 6:20
  Speaker 3: Yep, And they switch to a technique called evaporative cooling.
• 6:24
  Speaker 3: They hold this cold cloud of atoms in a magnetic field,
• 6:27
  Speaker 3: which basically acts like an invisible bowl.
• 6:29
  Speaker 2: An invisible bowl holding the atoms.
• 6:31
  Speaker 3: Then they slowly lower the rim of the bowl.
• 6:34
  Speaker 2: Oh, letting the hottest atoms spill over the edge.
• 6:37
  Speaker 3: Exactly. It's the exact same mechanism as a hot cup
• 6:40
  Speaker 3: of coffee cooling down on a desk. The most energetic
• 6:44
  Speaker 3: water molecules evaporate off the surface of steam, right.
• 6:47
  Speaker 2: Yeah, and they carry away the heat, leaving the rest
• 6:49
  Speaker 2: of the coffee colder.
• 6:50
  Speaker 3: Right. So, in the lab, the most energetic atoms climb
• 6:53
  Speaker 3: the magnetic walls and escape. The remaining atoms collide, redistribute
• 6:58
  Speaker 3: their energy, and set into an incredibly cold.
• 7:01
  Speaker 2: State, which brings us to the monumental breakthroughs of the
• 7:05
  Speaker 2: nineteen nineties, because when you drop atoms down to these
• 7:08
  Speaker 2: nanokelvin temperatures, they undergo a transformation that honestly sounds like
• 7:13
  Speaker 2: pure magic.
• 7:13
  Speaker 3: It really does. In nineteen ninety five, teams led by
• 7:17
  Speaker 3: Eric Cronell, Carl Wyman and Wolfgang Kettalog finally reach these temperatures,
• 7:21
  Speaker 3: and what they observed won them the two thousand and
• 7:23
  Speaker 3: one Nobel Prize.
• 7:25
  Speaker 2: Because the atoms just they change, right Yeah.
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  Speaker 3: When atoms get that cold, their fundamental identity blurs.
• 7:32
  Speaker 2: Blur. What do you mean by blur? Because I always
• 7:34
  Speaker 2: picture an atom as a very distinct solid thing.
• 7:37
  Speaker 3: Well, at room temperature, matter does act like individual particles.
• 7:40
  Speaker 3: But as momentum drops to year zero, the quantum wave
• 7:44
  Speaker 3: nature of the atom begins to stretch.
• 7:45
  Speaker 2: Out it's wave nature, right is.
• 7:47
  Speaker 3: Brillant wavelength grows. Eventually, the waves of adjacent adams get
• 7:51
  Speaker 3: so wide that they actually begin to overlap.
• 7:53
  Speaker 2: Oh wow, so they bleed into each other exactly.
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  Speaker 3: But here is where we have to divide the atomic
• 7:58
  Speaker 3: world into two distinct families. The first family is called bosons.
• 8:03
  Speaker 2: Bosons.
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  Speaker 3: Yeah, bosons have a quantum property called integer spin, and
• 8:08
  Speaker 3: in plain terms, integer spin is basically a rule that
• 8:12
  Speaker 3: makes these particles highly sociable social atoms. Okay, they are
• 8:16
  Speaker 3: entirely allowed to share the exact same quantum state and
• 8:20
  Speaker 3: the exact same physical space. So as those waves stretch
• 8:25
  Speaker 3: and overlap, these sociable bosons merge, they.
• 8:28
  Speaker 2: Lose their individuality entirely.
• 8:30
  Speaker 3: They do.
• 8:31
  Speaker 2: You know, the way I've always visualized this is to
• 8:33
  Speaker 2: think of a massive chaotic dance party. Okay, dance party,
• 8:37
  Speaker 2: I like that, right, So at room temperature. Everyone is
• 8:39
  Speaker 2: doing their own thing. They're bouncing off each other during
• 8:41
  Speaker 2: totally different moves. But cooling them down is like the
• 8:44
  Speaker 2: DJ suddenly dropping a very specific beat and without warning,
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  Speaker 2: every single person on the floor perfectly executes the exact
• 8:51
  Speaker 2: same synchronized dance routine. You can't even pick out individuals anymore.
• 8:55
  Speaker 2: You just see the pattern of the whole crowd moving
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  Speaker 2: as one giant entity.
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  Speaker 3: That's a great way to think about it. Millions of
• 9:01
  Speaker 3: individual atoms suddenly behaving as a single coherent wave function.
• 9:05
  Speaker 2: That is just wild.
• 9:07
  Speaker 3: What's fascinating here is that this state of matter is
• 9:10
  Speaker 3: called a bosin Stein condensate or a BC. You are
• 9:14
  Speaker 3: essentially holding a giant macroscopic quantum particle that you can
• 9:19
  Speaker 3: literally see with a microscope.
• 9:21
  Speaker 2: You can see it.
• 9:22
  Speaker 3: Yes, And because they are moving in total locksteps like
• 9:24
  Speaker 3: your dancers, BECs exhibit these completely alien properties like superfluidity. Superfluidity, Yeah,
• 9:31
  Speaker 3: a superfluid flows with literally zero friction.
• 9:34
  Speaker 2: Wait, wait, if there's absolutely no friction, what happens if
• 9:37
  Speaker 2: you try to like stir it, Does it just spin forever?
• 9:39
  Speaker 3: It spins forever? Yeah, but it can't spin like normal water.
• 9:42
  Speaker 3: What do you mean a superfluid refuses to rotate as
• 9:45
  Speaker 3: a solid body. Instead, it forms what are called quantized vortices.
• 9:49
  Speaker 3: Quantized vortices basically, they are tiny frictionless whirlpools where the
• 9:55
  Speaker 3: fluid circulates in discrete mathematical.
• 9:57
  Speaker 2: Units like tiny tornadoes.
• 9:59
  Speaker 3: Exactly, you get these beautiful grids of tiny tornadoes inside
• 10:02
  Speaker 3: the fluid.
• 10:03
  Speaker 2: Okay, frictionless tornadoes are wild, but there is one experiment
• 10:07
  Speaker 2: with a Bose Einstein condensate that absolutely shatters my brain.
• 10:11
  Speaker 3: Let me guess. Nineteen ninety nine.
• 10:14
  Speaker 2: Yes, in nineteen ninety nine, a team at Harvard led
• 10:17
  Speaker 2: by Lean Howe did something unbelievable with one of these beecs.
• 10:21
  Speaker 2: They used it to hit the brakes on light, a feat.
• 10:24
  Speaker 3: That still sounds like science fiction today.
• 10:26
  Speaker 2: It totally does. I mean, light moves at three hundred
• 10:29
  Speaker 2: million meters a second. It is the universal speed limit.
• 10:32
  Speaker 2: How do you sole that down just by shooting it
• 10:34
  Speaker 2: through some cold atoms.
• 10:35
  Speaker 3: Well, it comes down to how light interacts with this
• 10:38
  Speaker 3: synchronized quantum crowd we talked about. When the laser pulse
• 10:41
  Speaker 3: enters the beec, the light doesn't just pass through it.
• 10:44
  Speaker 3: It becomes entangled with the quantum state of the atoms.
• 10:47
  Speaker 2: The tangles up with them, right.
• 10:48
  Speaker 3: The light and the atoms temporarily merge to form this
• 10:51
  Speaker 3: hybrid entity called a polariton. Okay, And because the atoms
• 10:55
  Speaker 3: in the BC are so sluggish, they're incredibly dense and cold.
• 10:58
  Speaker 3: They act like a thick optical syrup. They grag the
• 11:01
  Speaker 3: propagation of the light down to a literal crawl.
• 11:04
  Speaker 2: And a crawl being seventeen meters per second. Yeah, that's
• 11:06
  Speaker 2: bicycle speed. They took the fastest thing in the universe
• 11:09
  Speaker 2: and made it slow enough that you could pass it
• 11:11
  Speaker 2: in a school zone.
• 11:12
  Speaker 3: Yeah, it's incredible.
• 11:13
  Speaker 2: And later they even managed to stop the light completely right,
• 11:17
  Speaker 2: turning the photons information into a physical imprint on the atoms,
• 11:21
  Speaker 2: just storing it and then releasing it back as light later.
• 11:24
  Speaker 3: Yeah, they paused light.
• 11:26
  Speaker 2: It is staggering. But we also have to talk about
• 11:29
  Speaker 2: the antisocial atoms, the ones that flat out refuse to
• 11:32
  Speaker 2: join the synchronized dance.
• 11:34
  Speaker 3: Ah. Yes, the second family of the atomic world, the
• 11:38
  Speaker 3: fermions ermions. These are atoms with half integer spin, so
• 11:41
  Speaker 3: unlike bosons, fermions are fiercely independent. They strictly obey the
• 11:47
  Speaker 3: poly exclusion principle, which is, it's a foundational rule of
• 11:50
  Speaker 3: physics dictating that no two fermions can ever occupy the
• 11:54
  Speaker 3: exact same quantum state.
• 11:55
  Speaker 2: Okay, so they are the stubborn partygoers. They flat out
• 11:58
  Speaker 2: refuse to wear the same outfit or do the same
• 12:00
  Speaker 2: dance as anyone else.
• 12:01
  Speaker 3: Right, they absolutely will not condense into a BC when
• 12:04
  Speaker 3: you cool them down. They just stack up in this
• 12:07
  Speaker 3: ladder of energy states, forming what we call a degenerate
• 12:10
  Speaker 3: fermi gas.
• 12:11
  Speaker 2: So they just stack up.
• 12:12
  Speaker 3: Yeah, but physicists are clever. They realize that if you
• 12:15
  Speaker 3: apply carefully tuned magnetic fields, you can trigger something called
• 12:19
  Speaker 3: a Feeshbach resonance.
• 12:21
  Speaker 2: Okay, what does that do?
• 12:22
  Speaker 3: It alters how the fermions interact with one another. It
• 12:25
  Speaker 3: basically tricks these stubborn independent atoms into pairing up.
• 12:30
  Speaker 2: And when two fermions pair up, their half integer spins
• 12:34
  Speaker 2: add together two halves make a hole, so they suddenly
• 12:37
  Speaker 2: have an integer spin exactly.
• 12:39
  Speaker 3: They become a mock boson and once they pair up,
• 12:42
  Speaker 3: that newly formed pair can flow as a skiper fluid.
• 12:45
  Speaker 3: Oh wow, And this is incredibly important because it perfectly
• 12:49
  Speaker 3: mimics one of the most vital phenomena in physics superconductivity.
• 12:53
  Speaker 3: Superconductivity electrons which carry electricity in our power lines. They're
• 12:58
  Speaker 3: also fermions. When they pair up in certain metals, they
• 13:01
  Speaker 3: flow without resistance, which brings up.
• 13:03
  Speaker 2: A really crucial question for me. I understand that making
• 13:06
  Speaker 2: frictionless liquids and hitting the brakes on light is cool
• 13:10
  Speaker 2: pun totally intended, but I have to ask the so
• 13:13
  Speaker 2: what question?
• 13:13
  Speaker 3: Okay, hit me?
• 13:14
  Speaker 2: Are we just playing an incredibly complicated, multi million dollar
• 13:18
  Speaker 2: video game with atoms here? I mean, we are building
• 13:20
  Speaker 2: these weird blobs and tricking atoms into pairing up. Why
• 13:24
  Speaker 2: build a fake crystal out of atoms in a lab
• 13:26
  Speaker 2: instead of just taking piece of real superconducting metal and
• 13:29
  Speaker 2: studying that?
• 13:30
  Speaker 3: That's a fair question. The answer is that nature is
• 13:33
  Speaker 3: really messy, messy how well a chunk of real copper
• 13:37
  Speaker 3: or a high temperature superconductor is completely riddled with impurities,
• 13:42
  Speaker 3: It has structural defects, complex thermal vibrations. The mathematical equations
• 13:47
  Speaker 3: required to predict how billions of interacting electrons will behave
• 13:50
  Speaker 3: in that chaotic environment are literally unsolvable even for supercomputers,
• 13:54
  Speaker 3: Even on our largest supercomputers, it's incredibly frustrating for physicists
• 13:58
  Speaker 3: trying to design new materials.
• 14:00
  Speaker 2: Okay, so imagine trying to fix a game breaking glitch
• 14:02
  Speaker 2: in a video game, but you aren't allowed to look
• 14:04
  Speaker 2: at the source code. You just have to keep blindly
• 14:07
  Speaker 2: mashing buttons on the controller to see what happens. So
• 14:09
  Speaker 2: the quantum simulator is like finally getting access to the
• 14:12
  Speaker 2: developer mode. You can build a perfect, clean replica of
• 14:15
  Speaker 2: the code, tweak one specific variable, and watch exactly what happens.
• 14:20
  Speaker 3: That is exactly what optical lattices provide. Scientists take intersecting
• 14:25
  Speaker 3: laser beams to create a standing wave of light. It
• 14:28
  Speaker 3: looks kind of like an invisible egg carton made of
• 14:30
  Speaker 3: pure energy.
• 14:31
  Speaker 2: An egg carton of light.
• 14:32
  Speaker 3: Yeah. Then they drop ultra coold atoms into the dimples
• 14:37
  Speaker 3: of this egg carton. The atoms hop from dimple to dimple,
• 14:40
  Speaker 3: perfectly mimicking electrons moving through the crystalline lattice of a
• 14:44
  Speaker 3: real metal.
• 14:45
  Speaker 2: So it really is just a perfectly clean scale model.
• 14:48
  Speaker 3: What's fascinating here is that they are realizing pure mathematical
• 14:51
  Speaker 3: equations in the physical world. Specifically, this setup solves the
• 14:56
  Speaker 3: Hubbard model.
• 14:56
  Speaker 2: The Hubbard model.
• 14:57
  Speaker 3: Yeah, it's a famous framework used to understand magnet and
• 15:00
  Speaker 3: how materials transition to superconductors. If we can solve the
• 15:04
  Speaker 3: Hubbard bottle, we can figure out how to manufacture room
• 15:07
  Speaker 3: temperature superconductors.
• 15:08
  Speaker 2: And that would change everything.
• 15:10
  Speaker 3: It would mean power lines that never lose energy, frictionless
• 15:13
  Speaker 3: maglev trains, perfect batteries, you name it.
• 15:16
  Speaker 2: And the breakthrough is happening right now, and these simulators
• 15:18
  Speaker 2: are just staggering. Like over at tu Ween researchers just
• 15:23
  Speaker 2: created a perfect conductor using ultra coold atoms.
• 15:26
  Speaker 3: Yes, that was huge.
• 15:27
  Speaker 2: They built this quantum wire where atoms collide constantly endlessly,
• 15:31
  Speaker 2: but the energy and mass just flow down the wire
• 15:34
  Speaker 2: without any dissipation whatsoever. It's a flawless transport system.
• 15:37
  Speaker 3: We're also seeing labs across the boundary of what we
• 15:40
  Speaker 3: even consider reality. Recently, the Southern University of Science and
• 15:45
  Speaker 3: Technology managed to generate macroscopic schroding Your cat states, Yeah,
• 15:49
  Speaker 3: using these ultra cool gases.
• 15:51
  Speaker 2: Wait, wait, a macroscopic cat state like Schwidener's famous thought
• 15:54
  Speaker 2: experiment about the cat being alive and dead at the
• 15:56
  Speaker 2: same time, but with a visible physical blob of atoms.
• 16:00
  Speaker 3: Precisely are you serious. Yes. By manipulating the condensate with
• 16:04
  Speaker 3: precise laser pulses, they split the wave function of the
• 16:07
  Speaker 3: entire cloud. Millions of atoms are placed into a superposition
• 16:11
  Speaker 3: where the entire macroscopic object is oscillating into completely different
• 16:14
  Speaker 3: states simultaneously. That is mind bending philosophically. This is tearing
• 16:19
  Speaker 3: down the wall between the microscopic quantum world, which we
• 16:23
  Speaker 3: expect to be weird, and the macroscopic classical world we
• 16:26
  Speaker 3: live in. It totally challenges our fundamental notions of measurement
• 16:29
  Speaker 3: and reality.
• 16:30
  Speaker 2: Wow, so we are testing mathematical models and exploring the
• 16:34
  Speaker 2: very fabric of reality. But I want to translate this
• 16:38
  Speaker 2: directly to the listener's life for a second. Sure, how
• 16:41
  Speaker 2: is this ability to perfectly control atoms going to end
• 16:44
  Speaker 2: up in our cars, or our phones or our infrastructure.
• 16:47
  Speaker 3: Well, we are watching the real time transition from foundational
• 16:51
  Speaker 3: science to commercial applied technology right now. The most immediate
• 16:55
  Speaker 3: impact is actually happening in timekeeping.
• 16:57
  Speaker 2: I'm keeping like clocks.
• 17:00
  Speaker 3: Yeah, we've developed optical lattice clocks using ultra cold strontium
• 17:03
  Speaker 3: or erbium atoms trapped in those exact egg cartons of light.
• 17:07
  Speaker 3: We talked about right.
• 17:07
  Speaker 2: And because the atoms are isolated from all that chaotic
• 17:10
  Speaker 2: thermal heat, their internal ticking, like the oscillation of their electrons,
• 17:15
  Speaker 2: is incredibly stable.
• 17:16
  Speaker 3: Exactly, these clocks achieve fractional uncertainties below ten to the
• 17:20
  Speaker 3: power of negative eighteen.
• 17:22
  Speaker 2: Okay, that's a lot of jargon. What does that actually mean?
• 17:25
  Speaker 3: To put that into perspective, if you had started one
• 17:28
  Speaker 3: of these clocks at the exact moment of the Big
• 17:31
  Speaker 3: Bang thirteen point eight billion years ago, it wouldn't have
• 17:34
  Speaker 3: lost or gained a single second.
• 17:36
  Speaker 2: By today, what not a single second? And thirteen billion years.
• 17:40
  Speaker 3: Not a single second. And we use this unbelievable precision
• 17:45
  Speaker 3: to test Einstein's theory of general relativity, to search for
• 17:49
  Speaker 3: the faint gravitational signatures of dark matter, and we are
• 17:53
  Speaker 3: currently even using them to officially redefine what a second
• 17:57
  Speaker 3: actually is.
• 17:58
  Speaker 2: That is insane, and beyond time, there is navigation right
• 18:01
  Speaker 2: atom interferometers. I've heard this term thrown around, but the
• 18:04
  Speaker 2: actual mechanics of it just blow my mind.
• 18:06
  Speaker 3: It relies heavily on that wave particle duality we discussed.
• 18:09
  Speaker 3: Because ultra cold atoms act like spreading waves. You can
• 18:12
  Speaker 3: take an atom's wave function and literally split it in
• 18:15
  Speaker 3: half using a laser pulse.
• 18:16
  Speaker 2: You just cut the atom in half.
• 18:18
  Speaker 3: The wave function. Yeah, you send the two halves the
• 18:20
  Speaker 3: atom down two different physical paths, and then you recombine them.
• 18:23
  Speaker 2: And how does splitting a wave help us figure out
• 18:25
  Speaker 2: where we are going?
• 18:26
  Speaker 3: Well, when the two waves recombine, they create an interference pattern,
• 18:30
  Speaker 3: a series of peaks and valleys. But while those waves
• 18:32
  Speaker 3: were traveling their separate paths, any slight change in gravity
• 18:36
  Speaker 3: or acceleration pulls on.
• 18:38
  Speaker 2: Them differently, oh, shifting the waves out of alignment exactly.
• 18:41
  Speaker 3: The resulting interference pattern is insanely sensitive to motion.
• 18:47
  Speaker 2: Right now, we rely heavily on GPS for everything, our
• 18:50
  Speaker 2: phones or cars. They constantly ping satellites in orbit. But
• 18:53
  Speaker 2: if you have an atom interferometer that perfectly measures every
• 18:57
  Speaker 2: microscopic change and acceleration and gravity around it, you don't
• 19:00
  Speaker 2: even need a satellite.
• 19:01
  Speaker 3: No, you don't.
• 19:02
  Speaker 2: We are talking about ultra precise inertial navigation systems. A
• 19:06
  Speaker 2: submarine could navigate perfectly while completely submerged deep underwater for months.
• 19:11
  Speaker 2: You could navigate deep underground in a mining operation, or
• 19:14
  Speaker 2: eventually deep in space, completely GPS free.
• 19:18
  Speaker 3: The ultra coold atoms inside the sensor act as a flawless,
• 19:21
  Speaker 3: unhackable compass.
• 19:23
  Speaker 2: That is going to change the world.
• 19:24
  Speaker 3: It really is. And finally, we have to mention the
• 19:27
  Speaker 3: race for quantum computing. Oh right, The tick industry is
• 19:30
  Speaker 3: aggressively pursuing neutral atoms for processing power. They are particularly
• 19:34
  Speaker 3: interested in highly excited Rideberg atoms.
• 19:38
  Speaker 2: Rideberg atoms. What makes an atom highly excited?
• 19:41
  Speaker 3: You hit the atom with a laser to bump its
• 19:43
  Speaker 3: outermost electron into an extremely distant orbit, so it gets bigger,
• 19:47
  Speaker 3: much bigger. The atom swells up, becoming thousands of times
• 19:51
  Speaker 3: larger than a normal atom. Because it is so huge,
• 19:54
  Speaker 3: its electric field easily interacts with its neighbors in the
• 19:57
  Speaker 3: optical lattice.
• 19:58
  Speaker 2: Oh, so they can talk to each other better exactly.
• 20:01
  Speaker 3: This allows them to perform incredibly fast and tangling operations,
• 20:05
  Speaker 3: and because they are ultra cold and neutral, they hold
• 20:07
  Speaker 3: onto their quantum information much longer than other computing architectures.
• 20:12
  Speaker 2: Though it's not like you can just drop one of
• 20:13
  Speaker 2: these into a laptop tomorrow, right. Getting this to work
• 20:16
  Speaker 2: outside of a meticulously controlled laboratory environment has to be
• 20:20
  Speaker 2: a monumental hurdle.
• 20:21
  Speaker 3: Oh, it is maintaining coherence. Basically, keeping that delicate quantum
• 20:26
  Speaker 3: state from collapsing is the great engineering challenge of our.
• 20:29
  Speaker 2: Time because anything could disrupt it.
• 20:31
  Speaker 3: Anything, any stray collision, a bit of scattered room light,
• 20:35
  Speaker 3: or even microscopic magnetic noise from a nearby power cord
• 20:38
  Speaker 3: can cause decoherence. The beautiful quantum wave just collapses back
• 20:43
  Speaker 3: into chaotic classical noise.
• 20:46
  Speaker 2: So just scaling these systems up from a few hundred
• 20:49
  Speaker 2: atoms to thousands, while keeping them perfectly isolated, that's what
• 20:53
  Speaker 2: labs worldwide are tirelessly working to solve right now exactly.
• 20:57
  Speaker 3: It's a massive global effort. Wow.
• 21:00
  Speaker 2: So to recap the wild journey we've taken today, we
• 21:02
  Speaker 2: start by taking everyday matter and violently pelting it with
• 21:05
  Speaker 2: lasers from all sides. We trap it in magnetic bowls,
• 21:08
  Speaker 2: evaporate away the remaining heat, and plunge it into the
• 21:11
  Speaker 2: nanokelvin depths. And when we do, the fundamental rules of
• 21:14
  Speaker 2: the universe just shift. Atoms lose their individuality, they merge
• 21:18
  Speaker 2: into frictionless superfluids, They create whirlpools of pure math. They
• 21:22
  Speaker 2: drag the speed of light to a dead stop, and
• 21:24
  Speaker 2: they become the pristine building blocks for the most accurate
• 21:27
  Speaker 2: clocks and navigational sensors humanity has ever seen.
• 21:30
  Speaker 3: Yeah, and consider one final, truly mind bending implication of
• 21:34
  Speaker 3: all this.
• 21:34
  Speaker 2: Lay it on me.
• 21:35
  Speaker 3: Because these ultra coold platforms give us such flawless, uncorrupted
• 21:39
  Speaker 3: control over quantum mechanics. Physicists aren't just simulating crystals anymore.
• 21:44
  Speaker 2: What else are they simulating?
• 21:46
  Speaker 3: They are currently using ultra coold atoms to simulate black
• 21:49
  Speaker 3: hole analogs.
• 21:50
  Speaker 2: Wait, really black holes?
• 21:52
  Speaker 3: Yes, they're using optical lattices to test quantum gravity inspired
• 21:56
  Speaker 3: models right on a lab bench. We are using the
• 21:59
  Speaker 3: small test coldest droplets of matter on Earth to decode
• 22:02
  Speaker 3: the physics of the most massive, extreme, and enigmatic objects
• 22:06
  Speaker 3: in deep space.
• 22:07
  Speaker 2: That is incredible, which brings us right back to the beginning.
• 22:10
  Speaker 2: You don't need a spaceship to explore the wildest extremes
• 22:13
  Speaker 2: of the cosmos. You just need to learn how to
• 22:15
  Speaker 2: freeze an atom. It is a brilliant reminder to stay
• 22:18
  Speaker 2: insanely curious because the universe is always ready to reveal
• 22:21
  Speaker 2: just how weird, wonderful, and deeply connected it truly is.