Time Crystals: The Next Breakthrough in Quantum Technology

<v Speaker 1>Welcome to the quark Side. Quantum Physics Podcast, an exploration
<v Speaker 1>of the fundamental structure of reality, where quantum laws govern matter, energy,
<v Speaker 1>and information. Here, uncertainty is a feature, not a flaw,
<v Speaker 1>and understanding begins at the smallest scales.
<v Speaker 2>Happy Valentine's Day. It is Saturday, February fourteenth, twenty twenty six.
<v Speaker 2>And look, I know exactly what you're thinking.
<v Speaker 3>Oh, I think they do two.
<v Speaker 2>You're expecting us to pivot into. I don't know the
<v Speaker 2>chemistry of oxytocin, or maybe the socioeconomic history of the
<v Speaker 2>greeting card industry.
<v Speaker 3>Or maybe why we give people roses which are covered
<v Speaker 3>in thorns. Seems like a mixed.
<v Speaker 2>Message, exactly a thorny flower as the ultimate symbol of affection.
<v Speaker 2>But we are going in a completely completely different direction.
<v Speaker 3>Today, a very very different direction.
<v Speaker 2>While the rest of the world is focusing on love,
<v Speaker 2>we're focusing on something well arguably more fundamental to the
<v Speaker 2>human experience, even if it sounds a lot less romantic.
<v Speaker 2>We are talking about precision, We're talking about order. We
<v Speaker 2>are talking about the ticking of the clock, but not
<v Speaker 2>just any clock. We are diving into a story that
<v Speaker 2>broke well essential yesterday about a strange, complicated, and frankly
<v Speaker 2>mind mending relationship between physics and time itself.
<v Speaker 3>It's a story about order, chaos and a state of
<v Speaker 3>matter that until very recently, and by recently I mean
<v Speaker 3>the last decade, people didn't even think could exist.
<v Speaker 2>Right.
<v Speaker 3>In fact, some very smart people proved it couldn't.
<v Speaker 2>Exist until they were proven wrong.
<v Speaker 3>Until they are proven wrong.
<v Speaker 2>Exactly, we are talking about time crystals. And before you
<v Speaker 2>hit pause or you know, roll your eyes, I need to.
<v Speaker 3>Make a disclaimer necessary one.
<v Speaker 2>No, we are not talking about an infinity stone from
<v Speaker 2>a Marvel movie. We aren't talking about a plot device
<v Speaker 2>from Doctor Who or some mystical New age healing stone
<v Speaker 2>you buy on Etsy to align your chakras.
<v Speaker 3>Although to be fair, the name time crystal does sound
<v Speaker 3>incredibly sci fi.
<v Speaker 2>Oh it's perfect sci fi.
<v Speaker 3>It sounds like something you'd find in a bad paperback
<v Speaker 3>novel from the nineteen seventies.
<v Speaker 2>It sounds totally made up. It sounds like flux capacitor.
<v Speaker 2>But it is hard science. We are talking about a
<v Speaker 2>new state of matter that breaks the rules of how
<v Speaker 2>we think structure and time actually work, and the reason
<v Speaker 2>we are talking about it today is because of our
<v Speaker 2>report that just came out.
<v Speaker 3>That's right. This comes from a report published yesterday February thirteen,
<v Speaker 3>twenty twenty six, on fizz dot org, written by Sam Jarman.
<v Speaker 3>But the core of our discussion, the meat on the bone,
<v Speaker 3>is based on a new study published in Physical Review Letters.
<v Speaker 2>Which, for those who don't follow the academic publishing horse race,
<v Speaker 2>is pretty much the heavy hitter of physics journals.
<v Speaker 3>Oh, it's the top tier.
<v Speaker 2>If you're publishing in PRL, you aren't just speculating, you've
<v Speaker 2>got the receipts.
<v Speaker 3>It is the gold standard. The research was led by
<v Speaker 3>lu Milaviati at the Abdessalam International Center for Theoretical Physics
<v Speaker 3>in Italy, and what they have put for word is well.
<v Speaker 2>It's a blueprint, a blueprint for what exactly.
<v Speaker 3>Or a clock, but not a clock like the one
<v Speaker 3>on your wall or even the one on your phone.
<v Speaker 3>They are proposing a quantum clock built on the backbone
<v Speaker 3>of these time crystals.
<v Speaker 2>So our mission today is to unpack this. We need
<v Speaker 2>to understand what these exotic systems are, and that is
<v Speaker 2>the technical term exotic, which usually means we don't fully
<v Speaker 2>understand it yet.
<v Speaker 3>Right, it's physics code for it.
<v Speaker 2>This is weird and how they could revolutionize everything from
<v Speaker 2>how we navigate the globe to how we detect magnetic fields.
<v Speaker 3>And honestly, it touches on the fundamental limits of quantum mechanics.
<v Speaker 3>It's not just about knowing what time it is. It's
<v Speaker 3>about understanding the nature of time itself and how we
<v Speaker 3>measure it against the background of a chaotic universe.
<v Speaker 2>Okay, that is a big promise. But before we get
<v Speaker 2>to the philosophy, we have to get through the physics.
<v Speaker 2>And I want to do this right. We aren't going
<v Speaker 2>to skim the surface today.
<v Speaker 3>Noh, let's get into the weeds.
<v Speaker 2>We are going to get into the weeds because that's
<v Speaker 2>where the interesting stuff is. So let's start at the
<v Speaker 2>very beginning. The phrase time crystal. It combines two words
<v Speaker 2>we know, but puts them together in a way that
<v Speaker 2>feels wrong.
<v Speaker 3>It does feel wrong.
<v Speaker 2>We know what a crystal is, diamonds, quartz, salt, ice, right,
<v Speaker 2>but when a physicist says crystal, what are they actually defining?
<v Speaker 2>Because I assume they aren't talking about jewelry.
<v Speaker 3>So yeah, let's strip away the aesthetic aspect. Yeah, in
<v Speaker 3>condensed matter physics, A crystal is defined very simply as
<v Speaker 3>a system that breaks spatial translation symmetry.
<v Speaker 2>Okay, you drop the s word early symmetry. We need
<v Speaker 2>to unpack that immediately. What does it mean to break
<v Speaker 2>spatial translation symmetry?
<v Speaker 3>Okay? Imagine you are floating in an infinite empty void,
<v Speaker 3>or simpler, imagine a perfectly smooth, infinite pool of water.
<v Speaker 3>It is completely uniform. Got it. If you close your
<v Speaker 3>eyes and I move you three feet to the left
<v Speaker 3>and you open your eyes, does the world look different, No, it.
<v Speaker 2>Looks exactly the same.
<v Speaker 3>It's just more water exactly. That system has continuous spatial
<v Speaker 3>translation symmetry. The laws of physics and the arrangement of
<v Speaker 3>matter are the same everywhere. It doesn't matter where you are.
<v Speaker 3>But now let's freeze that water into ice.
<v Speaker 2>Okay, so now we have a solid block.
<v Speaker 3>But if you zoom in with a microscope, that ice
<v Speaker 3>isn't smooth anymore. The water molecules have locked into a
<v Speaker 3>rigid lattice structure a pattern. A pattern. Maybe they are
<v Speaker 3>arranged in hexagons. Now, if you stand on a molecule
<v Speaker 3>and I move you a tiny bit to the left, say,
<v Speaker 3>into the empty space between molecules, does the world look different.
<v Speaker 2>Yes, because now I'm not on a molecule anymore. I'm
<v Speaker 2>in the gap.
<v Speaker 3>Correct. But if I move you exactly one lattice unit
<v Speaker 3>to the last ye, the exact distance between two molecules,
<v Speaker 3>you land on another molecule and it looks the same again.
<v Speaker 2>So the symmetry isn't continuous anymore. I can't just move
<v Speaker 2>any distance and have it look the same.
<v Speaker 3>That's it.
<v Speaker 2>I have to move specific, discrete distances to see the
<v Speaker 2>same pattern exactly.
<v Speaker 3>The formation of the crystal has broken the continuous symmetry
<v Speaker 3>of space. It has chosen a specific pattern. It has
<v Speaker 3>imposed order on the chaos. We call this a crystal,
<v Speaker 3>a repeating pattern in space.
<v Speaker 2>Okay, of salt, diamonds, checkerboards, they all break spatial symmetry. Now,
<v Speaker 2>how do we get to a time crystal? Because my
<v Speaker 2>brain wants to imagine a diamond that travels through time,
<v Speaker 2>which I know is wrong.
<v Speaker 3>That is wrong, but it's a fun image.
<v Speaker 2>That is a good image.
<v Speaker 3>No, to understand a time crystal, you have to take
<v Speaker 3>that same logic we just use for space and apply
<v Speaker 3>it to time.
<v Speaker 2>So time has symmetry.
<v Speaker 3>In physics, yes, we have time translation symmetry. It basically
<v Speaker 3>means that the laws of physics don't care when you
<v Speaker 3>run an experiment. If you mix baking soda and vinegar
<v Speaker 3>today at noon, it bubbles. If you do it tomorrow
<v Speaker 3>at midnight, it bawls. The same way. The laws are
<v Speaker 3>constant in time, energy is conserved, the system is stable.
<v Speaker 2>Okay, So breaking that symmetry would mean what that the
<v Speaker 2>laws of physics change.
<v Speaker 3>Not that the laws change, but that the system itself
<v Speaker 3>refuses to be constant in time. It means that even
<v Speaker 3>in its lowest energy state, its most comfortable rested state,
<v Speaker 3>it is changing. It is moving.
<v Speaker 2>Okay, let's unpack that sattern repeating in time.
<v Speaker 3>Imagine a material that, instead of looking the same, if
<v Speaker 3>you look three inches to the left, it.
<v Speaker 2>Looks the same if you look three seconds later.
<v Speaker 3>That's exactly it. It has a configuration that oscillates, it
<v Speaker 3>returns to its original state. It fixed intervals. It has
<v Speaker 3>a temporal structure. It effectively creates its own timeline. Tick
<v Speaker 3>tick tick.
<v Speaker 2>But wait, I have to play the skeptic here. Isn't
<v Speaker 2>that just anything that moves like a clock pendulum repeats
<v Speaker 2>in time? My heart beats in time. The turn signal
<v Speaker 2>on my car repeats in time. Why are those not
<v Speaker 2>time crystals? Why do we need a fancy new term
<v Speaker 2>for vibration.
<v Speaker 3>That is the million dollar question, and this is where
<v Speaker 3>it gets subtle and where we have to talk about thermodynamics.
<v Speaker 3>A pendulum, a heart, a turn signal. They all need
<v Speaker 3>energy to keep going. They need fuel. If you stop
<v Speaker 3>winding the Grandfather clock, the pendulum stops because of friction
<v Speaker 3>and air resistance. If you stop powering the turn signal,
<v Speaker 3>the light goes off. They are constantly losing energy to heat.
<v Speaker 3>They eventually wind down to a stop to equilibrit Right.
<v Speaker 2>Entropy comes for us. All the universe wants to be
<v Speaker 2>a lukewarm soup.
<v Speaker 3>Ideally, yes, yeah. In a standard system, the ground state,
<v Speaker 3>the state of lowest energy, where the system settles when
<v Speaker 3>you take away all the heat and excitement. Is static.
<v Speaker 3>It's motionless, a rock sitting at the bottom of a hill.
<v Speaker 2>But for a time crystal. You're saying, the ground state
<v Speaker 2>itself is moving.
<v Speaker 3>Precisely, a time crystal exhibits this repeating motion, this oscillation
<v Speaker 3>in its lowest possible energy state. It's not moving because
<v Speaker 3>you are pushing it. No external force, no external force.
<v Speaker 3>It's moving, because movement is its natural state of being.
<v Speaker 3>It breaks time translation symmetry spontaneously.
<v Speaker 2>WHOA stop there. You just described a system that moves
<v Speaker 2>forever in its ground state without energy input.
<v Speaker 3>I did.
<v Speaker 2>That sounds suspiciously like a perpetual motion machine. And the
<v Speaker 2>last time I checked, the first law of filmodynamics says
<v Speaker 2>no free lunch. Why isn't this violating physics?
<v Speaker 3>I love that you went there, because that was the
<v Speaker 3>exact controversy when this was first proposed. Image Nobel laureate
<v Speaker 3>Frank Wilchek propose this idea around twenty twelve, he asked,
<v Speaker 3>can a system break time symmetry the way a crystal
<v Speaker 3>breaks space symmetry? And the initial reaction for the community
<v Speaker 3>was basically, Frank, You've lost it. That's perpetual motion.
<v Speaker 2>So how is it not? How does it get around that?
<v Speaker 3>Because of the definition of work, A perpetual motion machine
<v Speaker 3>is impossible because it claims you can extract energy from
<v Speaker 3>it forever.
<v Speaker 2>Right, you can power something with it.
<v Speaker 3>You can hook it up to a turbine and power
<v Speaker 3>a light bulb a time crystal cannot do that?
<v Speaker 2>Why not? If it's moving, surely I can hook a
<v Speaker 2>gear to it.
<v Speaker 3>No, because the system is in its ground state, it
<v Speaker 3>has no excess energy to give you. If you try
<v Speaker 3>to hook a gear to it, you are interacting with it.
<v Speaker 3>You're adding resistance that collapses the quantum state. The moment
<v Speaker 3>you try to extract work, the time crystal breaks, it
<v Speaker 3>stops being a time crystal. So it moves forever, but
<v Speaker 3>it's useless for powering your car.
<v Speaker 2>So it's a closed loop.
<v Speaker 3>It's closed loop. It violates no laws because it generates
<v Speaker 3>no power.
<v Speaker 2>It's like a ghost pacing in a hallway. It's moving,
<v Speaker 2>but it can't turn a doorknob.
<v Speaker 3>That is a surprisingly accurate analogy. Yes, a perfect frictionless ghost.
<v Speaker 2>Okay, So Willcheck proposes this in twenty twelve, everyone says, maybe,
<v Speaker 2>then what happened because you mentioned we've known they exist
<v Speaker 2>for a decade.
<v Speaker 3>Well, there was a bit of drama. Some Japanese physicists
<v Speaker 3>Watanabi and Oshikawa proved a theorem, effectively saying will Check
<v Speaker 3>is wrong. You can't have a time crystal and thermal equilibrium.
<v Speaker 2>So it can't happen in that ground state you described, not.
<v Speaker 3>In a simple static equilibrium system. It was a heavy blow.
<v Speaker 3>It looked like the idea was dead.
<v Speaker 2>So the idea died.
<v Speaker 3>No, it pivoted. Physicists are clever. They realized, Okay, maybe
<v Speaker 3>we can't have them in perfect equilibrium, but what if
<v Speaker 3>we have them in a driven system, a system that
<v Speaker 3>we poke periodically, but the system responds in a weird way.
<v Speaker 2>This is what led to the twenty sixteen experiments.
<v Speaker 3>Exactly, in twenty sixteen, two different groups, one led by
<v Speaker 3>Chris Monroe and Maryland and another by Mikhyle Luken at
<v Speaker 3>Harvard created the first discrete time crystals.
<v Speaker 2>And how did they do that?
<v Speaker 3>They took ions, trap them in electromagnetic field, and hit
<v Speaker 3>them with lasers in a pulse bang bang, bang, a
<v Speaker 3>regular rhythm.
<v Speaker 2>So they were adding energy. That sounds like the pendulum.
<v Speaker 3>Again, they were adding energy. But here's the magic trick.
<v Speaker 3>They hit the system with a laser every t seconds.
<v Speaker 3>But the system didn't repeat every two seconds. It didn't
<v Speaker 3>know it repeated every two t seconds or three t seconds.
<v Speaker 3>It broke the symmetry of the driver. It adopted its own, slower,
<v Speaker 3>more stable rhythm.
<v Speaker 2>Wait, I want to make sure I get this. It's
<v Speaker 2>like if I'm jumping rope and the rope comes around
<v Speaker 2>every second, but I only jump every two seconds.
<v Speaker 3>Yes, you have created a new period that is different
<v Speaker 3>from the driving force. You're not just a puppet of
<v Speaker 3>the rope. You've established your own.
<v Speaker 2>Pattern and it holds that pattern rigidly, incredibly rigidly.
<v Speaker 3>That was the proof that the material was creating its
<v Speaker 3>own timeline. It wasn't just mirroring the laser. It was
<v Speaker 3>doing its own thing, locking into a sub harmonic frequency.
<v Speaker 2>So ten years ago we proved they exist. We found
<v Speaker 2>the loophole.
<v Speaker 3>We did We realized, Okay, nature actually allows this weird behavior. Yeah,
<v Speaker 3>but for the last ten years the conversation has been
<v Speaker 3>that's a cool party trick physics, but what can we
<v Speaker 3>actually do with it?
<v Speaker 2>It's the classic solution in search of.
<v Speaker 3>A problem exactly. And that brings us to twenty twenty
<v Speaker 3>six because the study we are looking at today, the
<v Speaker 3>Viati paper, moves the goalposts from look at this weird
<v Speaker 3>thing to let's build a machine with this.
<v Speaker 2>And the machine they want to build is the most
<v Speaker 2>precise clock in the universe.
<v Speaker 3>That's the ambition. And to understand why that is such
<v Speaker 3>a big deal, we have to talk about the villain
<v Speaker 3>of our story. The villain yes, the current status quill
<v Speaker 3>the atomic clock.
<v Speaker 2>Which begs the question what is wrong with the clocks
<v Speaker 2>we have now? I mean, my phone seems pretty accurate.
<v Speaker 2>The GPS on my car gets me to the grocery store.
<v Speaker 2>We have caesium clocks, strontium clocks. Why are scientists obsessed
<v Speaker 2>with making better clocks? Are we just splitting hairs at
<v Speaker 2>this point.
<v Speaker 3>It might seem like that, but for science and technology
<v Speaker 3>we are absolutely not splitting hairs. To answer that, we
<v Speaker 3>have to look at how we define time right now
<v Speaker 3>at the highest level, the level that governs GPS, the Internet,
<v Speaker 3>banking systems, and deep space navigation. We rely on optical atomic.
<v Speaker 2>Clocks, and these are the best we have.
<v Speaker 3>They are marvels of engineering. The latest strontium lattice clock,
<v Speaker 3>for instance, wouldn't lose or gain a second in about
<v Speaker 3>fifteen billion.
<v Speaker 2>Years, longer than the age of the universe exactly.
<v Speaker 3>So they are incredible, but they have some serious achilles heels.
<v Speaker 2>I've heard the term, but what is actually happening inside
<v Speaker 2>an atomic clock? It's not gears and springs, obviously.
<v Speaker 3>No, it's about energy levels and light. So let's look
<v Speaker 3>at a modern optical lattice clock. Imagine you have a
<v Speaker 3>vacuum chamber inside you trap thousands of atoms, usually strontium
<v Speaker 3>or yuterbium, using interfering laser beams.
<v Speaker 2>You're holding them with light.
<v Speaker 3>Holding them with light, were eating a shape like an
<v Speaker 3>egg crate. We call it an optical lattice. Each egg
<v Speaker 3>in the crate holds one atom, keeping them from bumping
<v Speaker 3>into each other and messing up the measurement.
<v Speaker 2>Okay, I've got my atoms. They are stuck in the
<v Speaker 2>egg crate.
<v Speaker 3>You cool them down, atom mean really cool. We use
<v Speaker 3>lasers to slow them down, a process called Doppler cooling
<v Speaker 3>to get them to microkelvin's barely above absolute zero. They're
<v Speaker 3>almost perfectly still.
<v Speaker 2>Okay, so we have frozen trapped atoms.
<v Speaker 3>Now what then you bring in the clock laser. This
<v Speaker 3>is a separate ultra stable laser tune too, a very
<v Speaker 3>specific frequency of light. You shine it on the atoms.
<v Speaker 3>If the frequency is exactly right, I mean exactly, it
<v Speaker 3>will excite the electrons in the atom to jump to
<v Speaker 3>a higher energy orbit.
<v Speaker 2>The quantum leap we were talking about the quantum leap.
<v Speaker 3>It's a very narrow resonance think of it like a
<v Speaker 3>key fitting a lock. Only one frequency will work. When
<v Speaker 3>you find that exact frequency that makes the jump happen,
<v Speaker 3>you know, okay, this frequency is our standard. You count
<v Speaker 3>the oscillations of that light. That is your tick.
<v Speaker 2>So the atom is the reference, it's the tuning for
<v Speaker 2>the laser is the bow playing the violin.
<v Speaker 3>That is a perfect analogy. The atom is the tuning fork,
<v Speaker 3>which is perfect and unchanging. The laser is the bow.
<v Speaker 3>But here is the problem with current technology.
<v Speaker 2>What's the problem.
<v Speaker 3>The ticked doesn't actually come from the atom. It comes
<v Speaker 3>from the laser. The laser is the thing generating the wave.
<v Speaker 3>We just use the atom to check if the laser
<v Speaker 3>is correct.
<v Speaker 2>So we're constantly asking the atom is this right? Is
<v Speaker 2>this right? Am I still on key?
<v Speaker 3>Yes, we lock the laser to the atom in a
<v Speaker 3>feedback loop. But lasers. Lasers are man made. They are imperfect.
<v Speaker 3>They have what we call phase noise. The mirrors in
<v Speaker 3>the laser cavity vibrate due to heat the electronics.
<v Speaker 2>Fluctuations, so the bow is shaky.
<v Speaker 3>The bow is shaky, and because the bow is shaky,
<v Speaker 3>we have to constantly correct it. This process creates a
<v Speaker 3>limit on stability. We are fighting a constant war against decoherence.
<v Speaker 3>What's that It's the laser noise scrambling the quantum information
<v Speaker 3>in the atoms. It's the external world messing up your
<v Speaker 3>perfect quantum state.
<v Speaker 2>And that limits how precise the clock can be.
<v Speaker 3>It limits the coherence time. Ideally, you want to interrogate
<v Speaker 3>the atom for a long time to get a precise measurement,
<v Speaker 3>but because the laser is noisy, you can't. You have
<v Speaker 3>to take short snapshots. It limits the ultimate precision.
<v Speaker 2>So the source material highlights these drawbacks. What are they specifically?
<v Speaker 3>Yes, it lists three big costs. First, complexity, these systems
<v Speaker 3>are absolute beasts. To manage you need vacuum chambers, multiple
<v Speaker 3>lasers for cooling, repumping, trapping, and the clock laser itself.
<v Speaker 3>It's a room full of equipment, so.
<v Speaker 2>You can't exactly wear one on your wrist or even
<v Speaker 2>put one in a small satellite easily.
<v Speaker 3>Definitely not. Second, they are fragile. They are incredibly sensitive
<v Speaker 3>to vibrations and temperature changes. If you shake them, the
<v Speaker 3>lattice breaks, the atoms fall out. And the third energy,
<v Speaker 3>and this is the big one for our discussion regarding
<v Speaker 3>the time crystal. To run an optical atomic clock, you
<v Speaker 3>are constantly blasting it with energy. You are driving the system.
<v Speaker 3>You are forcing the electrons up, they fall down, you
<v Speaker 3>push them.
<v Speaker 2>Up again, have to keep pushing the swing. If you
<v Speaker 2>stop pushing, the swinging stops.
<v Speaker 3>Exactly, you're constantly pumping energy into the system to force
<v Speaker 3>it to oscillate. This is an active system, and in
<v Speaker 3>quantum mechanics, active systems are prone to noise. The very
<v Speaker 3>act of pushing the atom disturbs it.
<v Speaker 2>So we have these amazing clocks, but they are energy hogs,
<v Speaker 2>They are fragile, and they only work because we are
<v Speaker 2>constantly bullying the atoms into keeping time.
<v Speaker 3>That's a very colorful way to put it, but yes,
<v Speaker 3>we are forcing order onto a chaotic system, and that
<v Speaker 3>brings us to Ludmilaviatti and her team.
<v Speaker 2>Enter the time crystal.
<v Speaker 3>Enter the time crystal.
<v Speaker 2>So the proposal from this news study published just this
<v Speaker 2>month February twenty twenty six is to throw out the
<v Speaker 2>idea of the bullied atom and replace it with a
<v Speaker 2>quantum time crystal clock.
<v Speaker 3>Right, And the core difference. The thing that makes this
<v Speaker 3>revolutionary is that a time crystal does not require that
<v Speaker 3>continuous energy intensive external excitation to sustain its oscillation in
<v Speaker 3>the same way.
<v Speaker 2>This goes back to what we said earlier. The rhythm
<v Speaker 2>is internal. It's not coming from a laser.
<v Speaker 3>Yes, the repeating pattern, the tick of the clock emerges
<v Speaker 3>from the intrinsic interactions within the system itself.
<v Speaker 2>I need an analogy because intrinsic interactions sounds like corporate
<v Speaker 2>speech for a team building exercise.
<v Speaker 3>Fair enough, Okay, think about the atomic clock the old way.
<v Speaker 3>Like a class of students trying to clap in unit
<v Speaker 3>in Okay, to get them to clap together, the teacher
<v Speaker 3>the laser has to stand at the front and conduct them. Clap, clap, clap.
<v Speaker 3>If the teacher stops, the students stop or fall out
<v Speaker 3>a rhythm.
<v Speaker 2>Okay, that's the external drive. Makes sense.
<v Speaker 3>Now, imagine a time crystal. The teacher leaves the room,
<v Speaker 3>but the students they hold hands. They're connected, they are entangled.
<v Speaker 3>They're quantum mechanically entangled. And because of the way they
<v Speaker 3>are connected, the specific physics of their interaction, a rhythm
<v Speaker 3>emerges from the group.
<v Speaker 2>So it's not imposed from the outside.
<v Speaker 3>Not at all. One student squeezes a hand, the next
<v Speaker 3>feels it and a wave of clapping propagates through the
<v Speaker 3>group and sustains itself. They keep the beat perfectly, not
<v Speaker 3>because someone is forcing them, but because the structure of
<v Speaker 3>their connection demands it.
<v Speaker 2>So the rhythm is a property of the collective, not
<v Speaker 2>the result of a conductor exactly.
<v Speaker 3>It provides a natural, built in rhythm. In physics terms,
<v Speaker 3>we say the system has a many body Hamiltonian that
<v Speaker 3>protects the coherence.
<v Speaker 2>Many body Hamiltonian. That sounds like a prog rock band.
<v Speaker 3>It does, but it essentially means. The math describing the
<v Speaker 3>energy of the system depends on all the particles interacting
<v Speaker 3>with each other, not just individually, and this interaction creates
<v Speaker 3>a stiffness or a rigidity in time.
<v Speaker 2>Rigidity is a good word, like how a diamond is
<v Speaker 2>rigid in space. You can't just push one atom out
<v Speaker 2>of place.
<v Speaker 3>Yes, that's a perfect way to think about it. If
<v Speaker 3>you try to bump one atom in a diamond, the
<v Speaker 3>bonds with this neighbors hold it in place. In a
<v Speaker 3>time crystal, if noise tries to bump the timing of
<v Speaker 3>one atom, the entanglement with its neighbors pulls it back
<v Speaker 3>into rhythm. It is self correcting.
<v Speaker 2>That is wild. So we are moving from a a
<v Speaker 2>high maintenance model to a self sustaining model.
<v Speaker 3>That is the hope, that's the promise of this whole idea.
<v Speaker 2>But how do you actually build a clock out of that?
<v Speaker 2>I mean, a circle of students holding hands is great,
<v Speaker 2>but the Audi's team isn't working with people. They're working
<v Speaker 2>with quantum particles. What did they do right?
<v Speaker 3>And this brings us to the simulation because to be clear,
<v Speaker 3>and I have to stress this, what this report details
<v Speaker 3>is a mathematical demonstration.
<v Speaker 2>They haven't built it yet.
<v Speaker 3>They have not built it. They simulated this engine on
<v Speaker 3>a powerful computer to see if it could actually keep
<v Speaker 3>time better than the conventional method.
<v Speaker 2>So let's look at the setup. What did they throw
<v Speaker 2>into the computer? What were the ingredients?
<v Speaker 3>They simulated an ensemble of one hundred quantum particles.
<v Speaker 2>Just one hundred. That seems low for something this revolutionary,
<v Speaker 2>you'd think.
<v Speaker 3>So, But in the quantum world, simulating one hundred interacting
<v Speaker 3>particles is actually a huge computational task. The complexity grows exponentially.
<v Speaker 3>The number of possible states is two to the power
<v Speaker 3>of one hundred, which is a number larger than the
<v Speaker 3>number of atoms in the earth.
<v Speaker 2>Okay, never mind, one hundred is a lot.
<v Speaker 3>You can't just run this on a laptop. They likely
<v Speaker 3>use sophisticated approximations like tensor networks to model it efficiently.
<v Speaker 2>Okay, fair enough, one hundred particles, and what are these
<v Speaker 2>particles doing.
<v Speaker 3>Each of these particles acts as a spin. You can
<v Speaker 3>think of it like a tiny magnet that can point up.
<v Speaker 2>Or down binary a quantum bit one or zero.
<v Speaker 3>Yes, but quantum so it can be a superposition of
<v Speaker 3>up and down at the same time. Now, they wanted
<v Speaker 3>to see if they could use this system to measure
<v Speaker 3>time using a technique called Ramsey interferometry.
<v Speaker 2>Ramsey interferometry, we need to define that. Is that standard practice.
<v Speaker 3>It's the gold standard way we measure time in quantum mechanics.
<v Speaker 3>It's a three step dance.
<v Speaker 2>Okay, let's hear the steps.
<v Speaker 3>Step one, you hit all the atoms with a quick
<v Speaker 3>pulse of microwave or laser radiation to put them in
<v Speaker 3>a superposition. Get them all spinning perfectly synchronized.
<v Speaker 2>Like spinning a top. One hundred tops all starting at
<v Speaker 2>the same time.
<v Speaker 3>Step two, you wait, this is the interrogation time. You
<v Speaker 3>let the atoms evolve freely. You let them tick. This
<v Speaker 3>is where the clock is actually running.
<v Speaker 2>Okay, so you just let them do their thing.
<v Speaker 3>Step three, you hit them with a second identical pulse
<v Speaker 3>to reout their state. This second pulse essentially stops the
<v Speaker 3>clock and allows you to measure how much their collective
<v Speaker 3>state has changed. By comparing the state at the end
<v Speaker 3>to the start, you know exactly how much time has passed.
<v Speaker 2>Got it. Pulse wait, pulse, measure the difference.
<v Speaker 3>Now in the simulation, they compare two different phases. This
<v Speaker 3>is the showdown part of the study.
<v Speaker 2>Phase one versus phase two, the old versus the new.
<v Speaker 3>Phase one is the conventional phase. In this simulation, they
<v Speaker 3>set up the particles so they would behave like a
<v Speaker 3>normal atomic clock. The particles were independent, They didn't talk
<v Speaker 3>to each other. They just evolved on their.
<v Speaker 2>Own, the lonely drummer phase, each one trying to keep
<v Speaker 2>its own beat right.
<v Speaker 3>And then they tried to measure time. Specifically, they looked
<v Speaker 3>at the stability of the clock, the precision. As they
<v Speaker 3>increased the interrogation time that weight period and what happened
<v Speaker 3>It hit the standard quantum limit. Basically, as time went on,
<v Speaker 3>small noises. Tiny fluctuations in the environment caused the atoms
<v Speaker 3>to dephase. They lost their synchronization.
<v Speaker 2>They started drifting.
<v Speaker 3>They started drifting, the signal got blurry. The precision degraded rapidly.
<v Speaker 3>If you imagine those hundred spinning tops, they all start
<v Speaker 3>spinning together. But after a while, summer a little faster,
<v Speaker 3>summer a little slower, and the whole thing is a mess.
<v Speaker 2>So the clock loses track of time if you wait
<v Speaker 2>too long.
<v Speaker 3>Exactly. Then they switched the simulation to phase two, the
<v Speaker 3>time crystalline.
<v Speaker 2>Phase, the entangled orchestra.
<v Speaker 3>They turned on the interactions. They set the parameters of
<v Speaker 3>the simulation so that the particles were strongly coupled to
<v Speaker 3>each other. They created that stiffness we talked about. They
<v Speaker 3>made the students hold.
<v Speaker 2>Hands, so now the tops are all connected by invisible strings.
<v Speaker 3>A great way to put it. And they ran the
<v Speaker 3>exact same Ramsey sequence pulse, wait, pulse, and the result.
<v Speaker 3>As a result, the precision remained far more robust. The
<v Speaker 3>graph I'm looking at Fig. Three in the paper mentally
<v Speaker 3>right now, shows that the variance, which is the measure
<v Speaker 3>of error, stayed flat for a much much longer time
<v Speaker 3>than in the conventional case.
<v Speaker 2>So the orchestra stayed in sync perfectly.
<v Speaker 3>The intrinsic interactions protected the phase of the clock. The
<v Speaker 3>entanglent thought off the decoherence from the environment.
<v Speaker 2>Here's where it gets really interesting for me, because usually
<v Speaker 2>in engineering, if you want more control, you add more control.
<v Speaker 2>You add more sensors, more feedback loops, more.
<v Speaker 3>Power, right, the brute force approach.
<v Speaker 2>But this result suggests that if you want the ultimate precision,
<v Speaker 2>you actually have to let go. You have to stop
<v Speaker 2>forcing the system and let it find its own stability
<v Speaker 2>through internal connection.
<v Speaker 3>That is a profound observation, and it's absolutely true. The
<v Speaker 3>stability of the time crystal comes from the fact that
<v Speaker 3>it is a many body system. It distributes the information
<v Speaker 3>of the time across all one hundred particles.
<v Speaker 2>It sounds like distributed computing or a blockchain. Almost the
<v Speaker 2>record isn't in one place, it's everywhere, so it's harder
<v Speaker 2>to corrupt.
<v Speaker 3>Very similar logic. If one particle gets knocked out a
<v Speaker 3>rhythm by a bit of noise, the other ninety nine
<v Speaker 3>pull it back in line. We call this Heisenberg limited scaling,
<v Speaker 3>or something close to it. It beats the standard quantum
<v Speaker 3>limit because the particles are acting as a single giant
<v Speaker 3>quantum object rather than one hundred small ones.
<v Speaker 2>So we have a simulation that says, hey, this weird
<v Speaker 2>state of matter we found ten years ago. It actually
<v Speaker 2>makes a better clock than the best technology we have today.
<v Speaker 3>In theory, yes, right, And specifically, it solves that external
<v Speaker 3>drive problem we talked about. Because the rhythm is internal.
<v Speaker 3>You don't need a nowsy laser to constantly drive the beat.
<v Speaker 3>You just need to initialize it and let it run.
<v Speaker 3>It's a passive clock.
<v Speaker 2>So yeah, what does this mean? Why should the listener care?
<v Speaker 2>I mean, I love a good clock, but I'm rarely
<v Speaker 2>late to meetings because my phone drifted by a nanosecond.
<v Speaker 2>This feels very esoteric.
<v Speaker 3>No, for you and me getting coffee, this doesn't matter.
<v Speaker 3>You will never need a time crystal to catch the bus.
<v Speaker 3>But for civilization, for our entire technology infrastructure, it matters
<v Speaker 3>a lot.
<v Speaker 2>Connect the dots. For us, where do we use clocks
<v Speaker 2>that need to be this good?
<v Speaker 3>The most obvious application is navigation. We all rely on
<v Speaker 3>GPS every single day.
<v Speaker 2>Which works by satellites sending timestamps.
<v Speaker 3>Yes, your phone listens for signals from multiple satellites. Those
<v Speaker 3>satellites are basically just flying atomic clocks. They send a
<v Speaker 3>signal saying the time I sent this was exactly twelve
<v Speaker 3>point zero zero zero zero zero zero zero zero zero
<v Speaker 3>zero one. Your phone compares the arrival times of signals
<v Speaker 3>from four different satellites to figure out where you are
<v Speaker 3>in three dimensional.
<v Speaker 2>Space triangulation or I guess quadrangulation.
<v Speaker 3>Right, But the accuracy of that location depends entirely on
<v Speaker 3>the accuracy of the clocks. Light travels very fast, about
<v Speaker 3>one foot per nanosecond a foot per nanosecond, so if
<v Speaker 3>the clock on the satellite is off by just a
<v Speaker 3>few nanoseconds, the error in your position could be several feet.
<v Speaker 2>So if the clock drifts, my GPS thinks I'm driving
<v Speaker 2>in the river instead of on.
<v Speaker 3>The bridge exactly Now, for your car, an error of
<v Speaker 3>a few feet is fine, but imagine a world of
<v Speaker 3>autonomous vehicles, drones delivering packages, and a growded city flying taxis.
<v Speaker 3>They need to know where they are within inches, not feet,
<v Speaker 3>and they need to know it instantly without fail.
<v Speaker 2>So we need better clocks in space, more stable clocks.
<v Speaker 3>And we need them to be stable, robust, and low power. Remember,
<v Speaker 3>current atomic clocks are fragile and power hungry. If we
<v Speaker 3>can build a time crystal clock, it could be smaller,
<v Speaker 3>require less power because it's self sustaining, and be more
<v Speaker 3>robust against the harsh radiation and vibration environment of space.
<v Speaker 2>That makes sense better GPS, safer self driving cars. But
<v Speaker 2>the report also mentions sensors. That seems like a different application.
<v Speaker 3>Entirely it is, but it's based on the same principle
<v Speaker 3>of stability. The source specifically mentions ultrasensitive detectors of magnetic fields.
<v Speaker 3>This is magnetometry.
<v Speaker 2>How does a clock detect a magnetic field?
<v Speaker 3>Well, remember that these particles are spins. They are essentially
<v Speaker 3>tiny magnets. The rhythm of the time crystal, the frequency
<v Speaker 3>of its oscillation, depends on the magnetic environment. It's in
<v Speaker 3>oh I see if an external magnetic field is present,
<v Speaker 3>it slightly alters the energy levels of the spins, which
<v Speaker 3>in turn changes the ticking rate of the clock in
<v Speaker 3>a very precise, predictable way.
<v Speaker 2>So it's a sensor. You measure the change in the
<v Speaker 2>ticking to measure the field.
<v Speaker 3>A quantum sensor. And because the time crystal is so
<v Speaker 3>stable against random noise, it becomes incredibly sensitive to specific
<v Speaker 3>signals like a magnetic field. It's like having a perfectly
<v Speaker 3>silent room where you can hear even the quietest whisper.
<v Speaker 2>What would we use that for?
<v Speaker 3>Everything from mineral exploration finding deposits of ore underground without digging,
<v Speaker 3>to non invasive medical imaging brain imaging. Your brain works
<v Speaker 3>by firing neurons. Those electrical currents create tiny, tiny magnetic fields. Currently,
<v Speaker 3>we use meg machines to detect them, but they are huge,
<v Speaker 3>they're expensive, and they require liquid helium cooling. A time
<v Speaker 3>crystal sensor could theoretically be a small room temperare device
<v Speaker 3>that is far more sensitive, allowing us to map brain
<v Speaker 3>activity with unprecedented detail. Wow.
<v Speaker 2>Okay, so we're talking about a fundamental leap in sensing technology.
<v Speaker 2>It's not just about time, it's about measuring the invisible
<v Speaker 2>forces of the world with incredible precision.
<v Speaker 3>Yes, but and there is always a butt And as
<v Speaker 3>the skeptic here, you should be waiting for it.
<v Speaker 2>I was waiting for it. I've been looking at the
<v Speaker 2>time stamp of our discussion and realizing we haven't solved
<v Speaker 2>the world's problems yet. Can I go to the hardware
<v Speaker 2>store and buy a time crystal clock today.
<v Speaker 3>No, you absolutely cannot. You can't even buy one from
<v Speaker 3>a high tech lab.
<v Speaker 2>Yet, why not If the simulation works, why don't we
<v Speaker 2>have the device? It sounds like the blueprint is there.
<v Speaker 3>Because, as I mentioned, this study by Viati and her
<v Speaker 3>team is a mathematical demonstration. It is a simulation. They
<v Speaker 3>prove that the physics works on paper and in a
<v Speaker 3>computer model.
<v Speaker 2>There is a big difference between a computer model and
<v Speaker 2>a physical device, a huge difference.
<v Speaker 3>The report explicitly quotes that there is a long road
<v Speaker 3>to practical applications.
<v Speaker 2>What are the roadblocks? What stands between us and this
<v Speaker 2>quantum future?
<v Speaker 3>Well, think about the requirements. To make this work. You
<v Speaker 3>need to create an ensemble of one hundred or more
<v Speaker 3>particles that are perfectly controlled and strongly interacting, and you
<v Speaker 3>need to keep them coherent for a long time.
<v Speaker 2>We can do that with quantum computers, right, Yeah, Google
<v Speaker 2>and IBM are building chips with lots of quibits.
<v Speaker 3>They are, but those systems are still incredibly noisy and
<v Speaker 3>error prone. Keeping one hundred particles entangled and coherent for
<v Speaker 3>a long period of time is the holy grail of
<v Speaker 3>quantum computing. We are getting better at it, but we
<v Speaker 3>aren't there yet. The engineering challenges are immense.
<v Speaker 2>So the time crystal clock relies on the same tech
<v Speaker 2>as quantum computers largely.
<v Speaker 3>Yes, it needs trapped ion technology or Ryberg atoms. You
<v Speaker 3>need to isolate these particles in a vacuum, cool them
<v Speaker 3>to near absolute zero, and then use lasers to engineer
<v Speaker 3>the interactions so they talk to each other in just
<v Speaker 3>the right way to form the time crystal state.
<v Speaker 2>So we are still talking about a room full of
<v Speaker 2>lasers and vacuum pumps. It's not a chick been a
<v Speaker 2>phone yet for now.
<v Speaker 3>Yes, we're at the Wright Brothers glider stage of this technology.
<v Speaker 3>Actually no, we're at the wind Tuttle blueprint stage. We
<v Speaker 3>know the aerodynamics work, we know the math holds up.
<v Speaker 3>Now someone has to actually bend the wood and stitch
<v Speaker 3>the canvas.
<v Speaker 2>But the hope is that this paper is the spark
<v Speaker 2>that lights the fire.
<v Speaker 3>Exactly. The goal of publishing this in Physical Review letters
<v Speaker 3>is to get the experimentalists excited. VIATI is basically saying, hey,
<v Speaker 3>to all my friends in the labs, look what the
<v Speaker 3>math says. If you build this, it will work.
<v Speaker 2>Here's the recipe and knowing physicists, they will tig that dare.
<v Speaker 3>Oh absolutely, the race is on Now. There are labs
<v Speaker 3>in Boulder, in Maryland, in Innsbruck that are likely reading
<v Speaker 3>this paper this morning and thinking can we reconfigure our
<v Speaker 3>trap to run this protocol.
<v Speaker 2>It is fascinating to think about the timeline here. In
<v Speaker 2>twenty twelve, this was just a crazy idea in Frank
<v Speaker 2>Wilcheck's head that everyone laughed at.
<v Speaker 3>Right perpetual motion.
<v Speaker 2>In twenty sixteen we saw it in a lab and realized, okay,
<v Speaker 2>it's real. Now in twenty twenty six we have the
<v Speaker 2>blueprint for a machine that uses it.
<v Speaker 3>It's a wrap acceleration. Usually new states of matter take
<v Speaker 3>decades to go from discovery to application. Superconductivity took half
<v Speaker 3>a century. This might happen in fifteen or twenty years
<v Speaker 3>from discovery to a working device.
<v Speaker 2>It really is incredible. So let's synthesize this. We've covered
<v Speaker 2>symmetry breaking, we've bashed traditional atomic clocks, and we've built
<v Speaker 2>a virtual time crystal. What is the big takeaway for me?
<v Speaker 3>The takeaway is a shift in philosophy for centuries. Precision
<v Speaker 3>meant control, It meant applying force. It meant holding nature
<v Speaker 3>down and forcing it to be regular clockwork, gears, pendulums, lasers.
<v Speaker 2>We imposed order on the world. We beat the chaos
<v Speaker 2>into submission.
<v Speaker 3>Yes, but this new research suggests that the ultimate order,
<v Speaker 3>the ultimate precision, comes from surrendering control. It comes from
<v Speaker 3>creating the right conditions and then letting a system settle
<v Speaker 3>into its own natural quantum rhythm.
<v Speaker 2>Moving from systems we have to force to keep time
<v Speaker 2>to systems that keep time because.
<v Speaker 3>Of what they are beautifully put. It's a move from
<v Speaker 3>artificials to ability to intrinsic stability.
<v Speaker 2>It really changes how you look at a clock. It's
<v Speaker 2>not just a tool. It's a reflection of how we
<v Speaker 2>interact with the universe. Are we fighting it or are
<v Speaker 2>we dancing with it?
<v Speaker 3>And that leads to a final thought. I want to
<v Speaker 3>leave with the listener little something to moll over. What's
<v Speaker 3>that We are taught in school that the universe tends
<v Speaker 3>toward disorder? The second law of thermodynamics, entropy always increases.
<v Speaker 2>Things fall apart.
<v Speaker 3>Things fall apart. If you leave a house alone, it
<v Speaker 3>gets dusty. If you leave a clock alone, it stops
<v Speaker 3>and rusts.
<v Speaker 2>Right, chaos wins in the end.
<v Speaker 3>But here we have a system that, left to its
<v Speaker 3>own devices, without continuous external energy, finds a perfect repeating
<v Speaker 3>order in time. It doesn't decay into randomness, it locks
<v Speaker 3>into structure. So my question is, if we can create
<v Speaker 3>machines that have an intrinsic, self sustaining rhythm, does that
<v Speaker 3>change how we think about entropy and disorder.
<v Speaker 2>Are we looking at a future where the most precise
<v Speaker 2>measurement of time comes from letting nature do its own thing,
<v Speaker 2>rather than for it with a laser.
<v Speaker 3>I think we are, And I think that suggests that
<v Speaker 3>order might be a more fundamental, more resilient property of
<v Speaker 3>the universe than we give it credit for. Maybe chaos
<v Speaker 3>doesn't always win.
<v Speaker 2>That is something to chew on while you are eating
<v Speaker 2>your Valentine's Day chocolates. Maybe order isn't something we have
<v Speaker 2>to build from scratch. Maybe it's waiting for us to
<v Speaker 2>just get out of the way.
<v Speaker 3>I like that thought.
<v Speaker 2>Thank you so much for joining us on this exploration
<v Speaker 2>of time crystals. If you want to dive deeper, and
<v Speaker 2>I mean really deep, like looking at the Hamiltonians yourself,
<v Speaker 2>check the show notes. We've linked the fizz dot org
<v Speaker 2>article and the references to the Vatti study and physical review.
<v Speaker 3>Letters definitely worth a read if you like the technical details.
<v Speaker 2>Until next time, stay curious.
<v Speaker 3>And keep watching the clock, or let the.
<v Speaker 2>Clock watch itself. By everyone