Speaker 1: Hey, Daniel, When you think of physics, what images come
Speaker 1: to mind for you? I think of the cosmos, I
Speaker 1: think of planets. I think of the fire inside the sun.
Speaker 1: I think of crazy people with weird hair when you
Speaker 1: look in the mirror. When you think of physics, what's
Speaker 1: the difference? Well, what about a dance party. I wouldn't
Speaker 1: say that's in the top one thousand associations I have.
Speaker 1: Might maybe not even in the top five thousand. Well,
Speaker 1: it turns out that physics and dance actually have a
Speaker 1: lot in common. They have a lot of fun connections.
Speaker 1: Is that right? Yeah, they can help us understand the
Speaker 1: topic of our podcast to day. That's right. Thinking about
Speaker 1: the way people dance and the way they shake their
Speaker 1: booty could actually help you understand the physics, the crazy
Speaker 1: topic of today's podcast. So get out there, shake your
Speaker 1: and get ready to download some physics into your brain.
Speaker 1: Get into the groove. It's time for physics. Hi'm h
Speaker 1: and I'm Daniel. Welcome to our podcast, Dancing with Physicists.
Speaker 1: How far can you get across the universe by just dancing? Now?
Speaker 1: We're just kidding. You were not the victim of clickbait.
Speaker 1: This is the podcast Daniel and Jorge explain the universe,
Speaker 1: in which we take something weird, something fascinating in the
Speaker 1: universe and try to explain it to you, sometimes using
Speaker 1: dance to be on the podcast, we're going to talk
Speaker 1: about a physics phenomenon that is everywhere. It's everywhere, and
Speaker 1: it's helping make some of the greatest scientific experiments in
Speaker 1: the world. That's right. It's really important, it's fascinating, it's weird,
Speaker 1: it's quantum, and yet it's not really very well understood.
Speaker 1: And more most important, it's super that's right. And it conducts.
Speaker 1: Uh what, it's conductive. There you go, that's right. The
Speaker 1: topic of today's podcast is super conductors. What are they?
Speaker 1: Who are they? Who are they? Super? No? Super conductivity
Speaker 1: is fascinating question, something behind a lot of really interesting
Speaker 1: research in the last few decades, and something we thought
Speaker 1: was worth getting into because there's a lot of puzzles there. Yeah.
Speaker 1: I was just thinking, the first time I heard about
Speaker 1: super conductors was in the eighties, right, and let's when
Speaker 1: it sort of became this big buzz about it. That's right.
Speaker 1: They had a lot of big advances in the eighties.
Speaker 1: How old were you in the eighties? Or I was
Speaker 1: old enough apparently to read about science news, but but
Speaker 1: you would always see it tied to the to this
Speaker 1: footage of this little magnet floating on top of something. Yeah,
Speaker 1: that's like a classic application of super conductivity. Yeah. Yeah, so,
Speaker 1: like I think forever, that's what people think of a
Speaker 1: lot of people think of when they think of super conductors,
Speaker 1: like that one image. Yeah, there's that. There's also the
Speaker 1: super conducting super collider that they were going to build
Speaker 1: in Texas in the nineties that was going to cost
Speaker 1: a huge amount of money and that they canceled halfway through.
Speaker 1: And so a lot of people connect those two phrases
Speaker 1: super conducting and super colliding. Oh yeah, no, I didn't
Speaker 1: hear about that one in the eighties. Um, So it
Speaker 1: sort of seems like it's been out there in the
Speaker 1: popular culture for a while, and but we were wondering
Speaker 1: how much people knew about it, and you know, it's
Speaker 1: part of the popular culture and the people maybe have
Speaker 1: heard about it or whatever. It's strangely, it hasn't really
Speaker 1: entered like, um, you know, um comic books or science
Speaker 1: fiction that much. You don't see like super conducting technology
Speaker 1: all over the place in science fiction. I mean, you
Speaker 1: haven't seen that comic called The super Conductor Adventures of
Speaker 1: Crime Fighting super Conductor. That's right, During the day, he's
Speaker 1: just a mild mannered, regular bus conductor, but at night
Speaker 1: he's a super duper conductor. No, I haven't seen that,
Speaker 1: and you don't see it. Um. You know, playing a
Speaker 1: prominent role in science fiction movies like particle physics is
Speaker 1: everywhere in science fiction movies. The Higgs boson explains everything
Speaker 1: and causes problems, etcetera. But you don't see super conductivity
Speaker 1: used and abused much in popular culture. Do you have
Speaker 1: I missed it? Yeah, I don't know. I guess it's
Speaker 1: not flashy, right, it's not um. It's not a word
Speaker 1: that sounds as cool as quantum or leasers or higgs boson. Yeah, exactly. Yeah. Anyway,
Speaker 1: so I went around campus and I asked people, do
Speaker 1: you know what super conductivity is? Can you explain it?
Speaker 1: Do you understand it? Here's what people had to say.
Speaker 1: What about super conductivity? Have you heard of that? Yes?
Speaker 1: Can you explain that? Best? Guess maybe it has two
Speaker 1: conductors and for some stuff. Okay, uh, yeah, I've also
Speaker 1: heard of it, but I also have no idea either. Okay, Um,
Speaker 1: it's a phenomena that happens at very low temperatures because
Speaker 1: electrons have very low resistance to movement due to the
Speaker 1: very slow vibrations of the matrix of the metal of
Speaker 1: the nucleus of the atom, so the electrons have a
Speaker 1: lot more space to move through. Something along those lines.
Speaker 1: Is that the one with the magnets and they could float.
Speaker 1: That's about all I know about that one where no
Speaker 1: I can guess though, Um, my conductivity with like wires,
Speaker 1: for example, or like metal so super conductive, then it's
Speaker 1: a good conductor, doesn't burn out. I would assume that
Speaker 1: it has something to do with objects that are conductive. Alright, Yeah,
Speaker 1: so I like the person who said that it has
Speaker 1: something to do with conductors and force and stuff. That's right.
Speaker 1: And there's somebody out there who clearly is reading the
Speaker 1: same magazine you were, because they're like, oh, it has
Speaker 1: to do with magnets that can float. Yeah, yeah, do
Speaker 1: you know which clip I'm talking about? I feel like
Speaker 1: they used the same clip for years and years and
Speaker 1: years and years and years. Yeah. I totally know what
Speaker 1: you mean. A little black magnet floating over a very
Speaker 1: cool surface. With like liquid hydrogen sublimating off of it.
Speaker 1: It's pretty cool looking. And then somebody comes and pokes
Speaker 1: the magnet and it just keeps floating there. Yeah, exactly exactly.
Speaker 1: So people had some sense, you know, they knew what
Speaker 1: it was. Nobody was like, I've never heard that word before,
Speaker 1: what are you talking about? Right, But nobody could explain
Speaker 1: it to me. Like some people knew you had to
Speaker 1: be cold to be a superconductor, but nobody could give
Speaker 1: me a solid explanation for what it was and how
Speaker 1: it worked. Right. I guess this one has something understandable,
Speaker 1: which is a conductor, and you know, I guess people
Speaker 1: in high school figure out that or learned that it's
Speaker 1: something that conducts electricity, and so a super conductor must
Speaker 1: just be something that is super ad That's right, it's
Speaker 1: awesome at conducting extracity. Right, that should be the next discovery.
Speaker 1: Awesome conductors. That's right. Superconductors last year, this year, awesome
Speaker 1: conductors next year, uber conductors. Um. But there is really
Speaker 1: something special about superconductors, which is not just that they
Speaker 1: can conduct a lot, but that they conduct with no
Speaker 1: resistance at all, where that you can't have anything better
Speaker 1: than a superconductor. So it is pretty amazing, and they
Speaker 1: are really important for things like particle physics, right, Yeah,
Speaker 1: they have a lot of really cool applications. So it's
Speaker 1: like a physics phenomenon that has really great applications for
Speaker 1: important experiments like the Large Hadron collider. That's right, And
Speaker 1: it's also a really fun physics puzzle. You know. The
Speaker 1: kind of physics that I do personally is like take
Speaker 1: everything apart and understand the smallest bits. That's totally worthwhile
Speaker 1: obviously and leads to deep insights. But there's a whole different,
Speaker 1: other kind of way of doing physics that's like can
Speaker 1: we put things together in a weird way that makes
Speaker 1: weird materials? You know, we have lots of materials around
Speaker 1: us on Earth that we're familiar with, but you can
Speaker 1: think like can we rearrange those bits to make new
Speaker 1: kinds of stuff. So there's a whole group of people
Speaker 1: out there in physics departments because basically all their job
Speaker 1: is is to make new kinds of goo, right, Like,
Speaker 1: let's mix this together and add a little bit of
Speaker 1: that and a little bit of this, and maybe if
Speaker 1: we zap it with a laser will get this weird
Speaker 1: crystal with strange behaviors that like nothing anybody's ever seen before.
Speaker 1: Are you talking about solid state physics? Yeah? These days
Speaker 1: I think they call it condensed matter physics. But essentially, yeah,
Speaker 1: it's like, can we build new kinds of stuff? It's
Speaker 1: like the properties of bulk materials, you know, UM, not
Speaker 1: individual particles, but like what happens when you put all
Speaker 1: these different kinds of particles together in a certain lattice
Speaker 1: and a certain in a certain arrangement. Do they behave
Speaker 1: in strange ways? And what can we learn about you know,
Speaker 1: what solids can and cannot do, right, because they do
Speaker 1: different things right, Like, you can make things behave in
Speaker 1: a totally different, a new way just by the way
Speaker 1: you arrange them. Yeah, and you know, the periodic table
Speaker 1: is the first lesson of that. Everything in the periodic
Speaker 1: table is made out of the same bits, right, protons
Speaker 1: and neutrons and electrons, but they're pretty different, right. Uranium
Speaker 1: is pretty different stuff than lithium, for example, And so
Speaker 1: you can get an incredible variety of behaviors just by
Speaker 1: rearranging the same stuff. And so solid state physics, that
Speaker 1: whole field UM is just taking that to in extremes
Speaker 1: like how can we combine these elements and zap them
Speaker 1: and chill them and heat them and do all sorts
Speaker 1: of crazy stuff. It's basically like cooking, right, what kind
Speaker 1: of cakes can you make with the same ingredients right
Speaker 1: that that taste totally different exactly and can float above
Speaker 1: your countertop? Right? Super connecting cakes, that's the next breakthrough.
Speaker 1: This is just renaate that department stuff physics, physics, stuff,
Speaker 1: physics of stuff. Yeah, exactly, the physics of stuff. Hey,
Speaker 1: stuff is pretty interesting. Rights, the whole podcast called stuff.
Speaker 1: You should know how stuff works? Then we should join
Speaker 1: that podcast network. I think there's stuffed pretty full cool.
Speaker 1: So let's get into it all right, um, and let's
Speaker 1: break it down. So let's what's a superconductor. Let's start
Speaker 1: with just the conductor part. Dig in a little bit
Speaker 1: into what it means to be a conductor, right, So,
Speaker 1: a conductor is something where electricity can move through it, right,
Speaker 1: And you have to understand the electricity moving through it
Speaker 1: is not necessarily the same as like electrons flowing through it.
Speaker 1: You put the electricity on one side of a of
Speaker 1: a wire and you get electricity on the other side
Speaker 1: of the wire. It's tempting to think about it like
Speaker 1: a hose, like you put water on one side and
Speaker 1: water comes out the other side. Like a tube. Yeah,
Speaker 1: like a tube. And you know what happens is you
Speaker 1: put electrons in on one side and the electrons all
Speaker 1: sort of shift over like it's it's like a tube
Speaker 1: full of water. You put a little bit of water
Speaker 1: in the front, and a little bit of a different
Speaker 1: piece of water that was already in there pushes out
Speaker 1: the side. It's kind of like um, if you have
Speaker 1: a two and you blow in it. The air that
Speaker 1: comes out the the end is not necessarily the air
Speaker 1: they came out of your mouth. It's like it causes
Speaker 1: some sort of it pushes all the air through and
Speaker 1: the ones that come out are the ones that we're
Speaker 1: waiting closest to the end exactly. And that's only possible
Speaker 1: if the electrons can move. Right. And so a conductor
Speaker 1: is just any material where you have electrons that can
Speaker 1: jump from atom to atom. Right. Think about a material
Speaker 1: and a microscopic scale, it's really a bunch of atoms, right,
Speaker 1: And if it's simple or regular, then it's like a
Speaker 1: lattice like a grid, and it's like regularly distributed atoms,
Speaker 1: and the electrons can jump from one to the other.
Speaker 1: So if you blow on one side, you like pushing
Speaker 1: about some electrons on one side, then all the electrons
Speaker 1: sort of hop over one slot and you get some
Speaker 1: out the other side. It's kind of like, um, like
Speaker 1: playing hot potato. Yeah exactly. And the difference between something
Speaker 1: that can conduct electricity a conductor, and something that can't,
Speaker 1: an insulator, is that conductors have enough electrons that can
Speaker 1: jump between atoms, whereas insulators have all their electrons held
Speaker 1: really tight by each of those atoms in the grid,
Speaker 1: so that there's no way for the electrons to jump
Speaker 1: from one to the other. Conductors have these free electrons
Speaker 1: that are sort of just like floating around happily. Okay,
Speaker 1: So it's something that is not a conductor doesn't have
Speaker 1: kind of a spare electrons, or they don't they don't
Speaker 1: let electrons fly around freely. Yeah exactly. And so and
Speaker 1: you just you know, you put electrons on one side
Speaker 1: and they just go nowhere, right, So you can't get
Speaker 1: electrons through the material. Okay, so wait, wait, why not?
Speaker 1: So I introduce an electron in an insulator and something
Speaker 1: that doesn't conduct what's going to happen to the electron?
Speaker 1: It won't go through, yeah, it just it won't cause
Speaker 1: a current. Right, you can't get a current through there.
Speaker 1: You can't get all the electrons to jump over one
Speaker 1: atom for example. Okay, so it's kind of like, Um,
Speaker 1: a conductor has a bunch of atoms, and everyone kind
Speaker 1: of has everyone's pretty loose with their electrons. That's right. Okay,
Speaker 1: here's one. Oh, I'll take one. R I'll give you
Speaker 1: another one. Oh. Um, electrons can just kind of flow
Speaker 1: through from atom to atom. Yeah, And it's best to
Speaker 1: think of them really as a lattice, because these atoms
Speaker 1: individually act a little different than they do when they're
Speaker 1: together in a material. And when they're together in a material,
Speaker 1: the electrons slash easily back and forth between them. Um,
Speaker 1: for a conductor, for an insulator, that doesn't happen. And
Speaker 1: then of course there's lots of different kinds of conductors
Speaker 1: that things that are good conductors and things that are
Speaker 1: bad conductors. And by a lattice, you mean like a
Speaker 1: like a grid or like a like a rack, Like
Speaker 1: the electrons are arranged kind of like um in rows
Speaker 1: and in columns, right, Yeah, exactly. If you zoom in
Speaker 1: on a crystal, for example, or a piece of metal,
Speaker 1: anything that has a regular arrangement of the atoms, you'll
Speaker 1: see that they're organized in this in this pattern right there,
Speaker 1: built out of these basic units, and that they're pretty regular.
Speaker 1: You know, there's like lines of atoms. Um, it's not
Speaker 1: just like a big heaping mess. Right. Um, These these solids,
Speaker 1: these metals, these things that are conductors are pretty well organized,
Speaker 1: and so you'll see them in rows and and uh.
Speaker 1: And that's what we mean by the lattice. You have
Speaker 1: just like a grid of atoms. And so you're saying
Speaker 1: like us can flow through or jump freely between atoms,
Speaker 1: but not perfectly right, that's right. And here's where the
Speaker 1: temperature comes in. So, Um, the colder the material is.
Speaker 1: Think about what temperature really is. What is temperature? It's
Speaker 1: how much the atoms inside something are wiggling. The atoms
Speaker 1: inside liquid are wiggling more than the atoms inside of solid, right,
Speaker 1: which is why it's liquid, and the atoms inside of
Speaker 1: gas are totally free and bouncing around everywhere. But even
Speaker 1: inside of solid, even if it's solid, you have different temperatures. Right,
Speaker 1: You can have a piece of metal that's hot or
Speaker 1: piece of metal that's cold. What's happening there is that
Speaker 1: the atoms are moving less, right, They're wiggling less, and
Speaker 1: as it gets colder and colder, they wiggle less and
Speaker 1: less and less. And this is important for the electron
Speaker 1: because remember, it's trying to jump from atom to atom.
Speaker 1: That's easier when the atoms are not wiggling around, when
Speaker 1: they're like regularly spaced rows, like when they're frozen in place. Yes, exactly.
Speaker 1: Here's where the dance analogy comes in. Right. Imagine trying
Speaker 1: to walk through a crowd and everybody's like jumping. It's
Speaker 1: like a mosh pit, right, and they're going crazy into
Speaker 1: punk consider or something. It's really hard to get across
Speaker 1: the crowded room if everybody's jostling and bouncing and moving
Speaker 1: around a lot, Right, It's much easier if they're calm,
Speaker 1: if they're like, you know, slow dancing or something. It's
Speaker 1: kind of like, yeah, you would. If it's a marsh
Speaker 1: pit and everyone's moving and dancing, you would just kind
Speaker 1: of lose a lot of energy just kind of bumping
Speaker 1: against people and just trying to make it through. Exactly.
Speaker 1: You would lose a lot of energy. That's exactly right.
Speaker 1: It's the resistance, right. So electrical resistance is electrons losing
Speaker 1: energy as they bump into the atoms that are wriggling
Speaker 1: around because they're moving like. It's related to the kinetic
Speaker 1: motion of the atoms. Yeah, absolutely, it's related to the
Speaker 1: kinetic motion of the atoms. It makes it harder for
Speaker 1: the electrons to get through and as they get through,
Speaker 1: they lose some energy. Right. Okay, so that's resistance, right,
Speaker 1: that's um vehicles. The resistance of a wire or a conductor,
Speaker 1: that's what it is. It's it's like electrons going through
Speaker 1: but sort of bumping too much into the atoms. That's it.
Speaker 1: And so things that are conductors have low resistance, and
Speaker 1: you want to use things that have low resistance so
Speaker 1: that most of the energy you're sending along a wire,
Speaker 1: for example, gets there. And if you use something with
Speaker 1: low resistance like copper or gold, then most of the
Speaker 1: energy you put into a wire will get to the
Speaker 1: other side. If you use something with really bad resistance,
Speaker 1: with a lot of resistance, then it will heat up
Speaker 1: the wire. That energy from the electrons will create resistance,
Speaker 1: which turns into heat and that's not good. But sometimes
Speaker 1: you sort of want resistance, right, Like in circuits, some
Speaker 1: resistors are sometimes good. Yeah, sometimes you want resistance so
Speaker 1: you can put it in on purpose. For example, a
Speaker 1: light bulb, that's a resistor, right. What it does is
Speaker 1: it steals the energy from the electrons and it heats
Speaker 1: of the material, which then glows and gives you light.
Speaker 1: Awesome if that's what you wanted, right, But you don't
Speaker 1: really want them wires in your house glowing. You want
Speaker 1: them to transmit that energy to your iPhone or whatever
Speaker 1: it is you're sending. And those power lines along the road, right,
Speaker 1: we don't want those heating up and melting. Want those
Speaker 1: to transmit the energy from the power station to your
Speaker 1: house without losing much energy. Unless you your house is
Speaker 1: a dance floor, that would be pretty cool, Like, well,
Speaker 1: how are you going to power those speakers without the electrons? Well,
Speaker 1: the speakers will glow too. Sounds like an awesome party,
Speaker 1: Send me an invite. And I think that brings us
Speaker 1: to the cool point, which is that the resistance of
Speaker 1: a conductor depends on the temperature. Yeah, exactly, So as
Speaker 1: it gets colder, the lattice, this grid of atoms gets
Speaker 1: more regular, and it gets easier for the electrons to
Speaker 1: get through, and so the resistance goes down with temperature.
Speaker 1: So hot wire is harder to get electrons through it
Speaker 1: because all the apps are are moving more. But a
Speaker 1: cold wire lets the electrons flow easy, more easy. That's right,
Speaker 1: all right, cool, that's that's a conductor, not somebody who
Speaker 1: drives a bus or directs an orchestra. That person is
Speaker 1: also a conductor. Yeah, but is he a superconductor? Is
Speaker 1: he resistant? Does he glow? Does he steal energy from
Speaker 1: innocent electrons? All right, that's a conductor, And now let's
Speaker 1: get into superconductors. But first let's take a quick break,
Speaker 1: all right, Daniel, So it fills in what is a
Speaker 1: super conductor and what is so super about them? Superconductors
Speaker 1: are really pretty super. The thing that makes them super
Speaker 1: is that they have zero resistance, not just like very small,
Speaker 1: not like Ebsalon resistance, but zero, like zero point zero
Speaker 1: zero zero zero. Keep going with the zeros there, man,
Speaker 1: because it's zero all the way. Okay, Yeah, it's pretty crazy.
Speaker 1: It means that, for example, if you had a loop
Speaker 1: of super connecting wire, you could put a current into
Speaker 1: it and it would just zoom around it forever. It
Speaker 1: would like never get used up. It's a pretty hard
Speaker 1: concept to imagine. It's like, it's like living in a
Speaker 1: world without friction. And you know, it's like imagine you
Speaker 1: had a sheet of ice, you pushed a block on it, right,
Speaker 1: you expect it to go for a while and then
Speaker 1: eventually slow down because every surface has some friction. But
Speaker 1: what if you had a perfectly smooth surface with no
Speaker 1: resistance and you pushed it, it would just go forever.
Speaker 1: It's like a perpetual motion machine. Yeah, sort of like that.
Speaker 1: Or is it kind of like if you if you're
Speaker 1: out in space and you start spinning something a top,
Speaker 1: It's just going to keep spinning for a long time
Speaker 1: because there's nothing there's no air, no resistance, no nothing
Speaker 1: to stop it from spinning. That's right, yeah, exactly. And
Speaker 1: so a superconductor is something that has zero resistance and
Speaker 1: so the electrons can just flow right through it. It's
Speaker 1: pretty amazing, all right. So let's get into how that works.
Speaker 1: And I think what's cool I heard is that physicists
Speaker 1: don't really know what's going on. Yeah, well, there's some
Speaker 1: there are different kinds of superconductors, and some of them
Speaker 1: are pretty well understood, the old fashioned ones, the classic ones.
Speaker 1: But rees they've made a bunch of really strange superconductors
Speaker 1: um that nobody really understands in great detail. I mean,
Speaker 1: we have some simulations we can describe it, but a
Speaker 1: lot of it's just too complicated or like write down
Speaker 1: equations on paper that we can understand. Okay, So there's
Speaker 1: different flavors of superconductors. Yeah, the first thing they all
Speaker 1: have in common is that you've got to get it cold.
Speaker 1: Like we were saying earlier, you want to lower the
Speaker 1: resistance first, get it cold, and so chill that thing down.
Speaker 1: And people built refrigerators to get things down to like
Speaker 1: really really really cold temperatures like ten or twenty degrees kelvin.
Speaker 1: You know, that's like just above absolute zero. And and
Speaker 1: the point is that one gets colder that cold, the
Speaker 1: grid in the material stops moving, it stops vibrating, right,
Speaker 1: that's right. And you can't get anything down to actually
Speaker 1: absolute zero, but you can get it down really really cold,
Speaker 1: and the grid stops vibrating, as you say, and then
Speaker 1: it gets easier and easier for electrons to go through,
Speaker 1: and so that will bring you down to low resistant,
Speaker 1: even very low. Some might even say super low, but
Speaker 1: it won't get you all the way down to zero resistance. Oh,
Speaker 1: I see, if you just had a regular like if
Speaker 1: I took a copper wire and I froze it to
Speaker 1: almost zero kelvin, it would give me pretty low resistance,
Speaker 1: but not necessarily zero resistance. I don't actually know if
Speaker 1: copper can become a superconductor, but I just mean that
Speaker 1: chilling it down is not the all the explanation. To
Speaker 1: explain how something loses its resistance. You need more than
Speaker 1: just understanding that it gets colder and therefore it's easier
Speaker 1: for the electrons to go through. You need there's another
Speaker 1: piece of the explanation. There's some extra magic going on there,
Speaker 1: some extra dance magic. Yeah, exactly, because physics, if you
Speaker 1: just think about the temperature physics as you shouldn't have superconductors,
Speaker 1: but we do have them. It was in the early
Speaker 1: part of the twentieth century that people made superconductors and
Speaker 1: observed it, and people thought, what, how is this even possible?
Speaker 1: And then the theorists spend decades thinking about it and
Speaker 1: trying to come up with explanations like we know this exists, right,
Speaker 1: this one favorite things in science when we have something
Speaker 1: we know it exists, but we don't know how it
Speaker 1: can work, Like it doesn't seem like it should be possible.
Speaker 1: Yet here we have one. And then one night they
Speaker 1: went dancing and they figured it all out. That's right.
Speaker 1: They were getting knocked over in the mosh pit, and
Speaker 1: when they woke up from their concussion, they had a
Speaker 1: brilliant idea. Well, that's that's kind of the analogy here, right, Like, Um,
Speaker 1: if you're this is a dance party and there's a
Speaker 1: mosh bit and people are jumping and going crazy, it'd
Speaker 1: be really hard to go through it. But if you
Speaker 1: suddenly turn out the music and everyone did the manne
Speaker 1: Can challenge, it would be a lot easier to walk
Speaker 1: through it. But it wouldn't be perfectly easy to go through.
Speaker 1: You still might bump into people, rub against people, and
Speaker 1: so the resistance would be low, but not zero. That's right.
Speaker 1: So to get down to zero and took a really
Speaker 1: clever bit of thinking boy theorists to explain how this
Speaker 1: could work. And it comes down to a concept called
Speaker 1: Cooper pairs. And the short version of the explanation is
Speaker 1: that lecture don't go through individually, they gather together into
Speaker 1: pairs like you know, like pair dancing, um, like you know,
Speaker 1: square dancing or waltzing or whatever. Oh my goodness, the
Speaker 1: dance analogies don't stop. Why should they write? It's a
Speaker 1: dance party to the end of time? Um, and going
Speaker 1: through in pairs they can accomplish actually zero resistance, okay,
Speaker 1: so um, it's sort of related to some quantum effects, right, Like,
Speaker 1: at some point to get to zero resistance, you need
Speaker 1: that sort of quantum magic to make an up. Yeah,
Speaker 1: which is really awesome because it's really fun when quantum
Speaker 1: mechanics is not just like hidden under the rugs, some
Speaker 1: tiny little effect that only affects tiny particles, when it
Speaker 1: actually gives you a macroscopic thing that you can measure,
Speaker 1: that you can see, you can prove. Look, quantum mechanics
Speaker 1: is real and this is an example of that. And
Speaker 1: to understand it, a little bit of quantum mechanics you
Speaker 1: need to know is just that electrons are a certain
Speaker 1: kind of particle we call them fermons, and that kind
Speaker 1: of particle doesn't like to share. It doesn't like to
Speaker 1: be in the same state as another kind of article.
Speaker 1: So you can't have two electrons both occupying, for example,
Speaker 1: the lowest rung on the energy ladder of an atom.
Speaker 1: They don't like to be in the same one. So
Speaker 1: this one already there, the next one will feel the
Speaker 1: second rung, and the next one will feel the third rung.
Speaker 1: They don't all like to hang out together on the
Speaker 1: bottom rung, right, Usually they like to dance solo. That's right, exactly.
Speaker 1: They all think they're the best dancer ever Ene danced
Speaker 1: by themselves in the Dance Lord. But what happens when
Speaker 1: you get two of them together is that they act
Speaker 1: like the other kind of quantum particle. We call those bosons,
Speaker 1: And bosons are totally happy to pile up on top
Speaker 1: of each other and they can occupy the same state,
Speaker 1: no big deal. Maybe you've heard of a Bose Einstein condensate.
Speaker 1: That's an example of a bunch of bosons getting really
Speaker 1: really cold and all sitting in exactly the same quantum state,
Speaker 1: the lowest energy state, and then they all act together
Speaker 1: and do really weird quantum effects. We should do a
Speaker 1: whole podcast on the Bosonstein condensate. That's pretty cool stuff.
Speaker 1: But there's something going on because normally electrons don't like
Speaker 1: to pair up like this, But when you cool down
Speaker 1: a superconductor, suddenly it becomes possible and even preferable for
Speaker 1: them to pair up. Yeah. Well, electrons are both negatively charged, right,
Speaker 1: and so they don't like to hang out with each other.
Speaker 1: They repel each other quite a bit. But you only
Speaker 1: need a very slight attraction this. These Cooper pairs are
Speaker 1: not like they're not like really bound tightly together, just
Speaker 1: sort of like loosely associated. You know, they're like two
Speaker 1: people eyeing each other across the dance floor, sending signals
Speaker 1: back and forth. So can you describe the effect here,
Speaker 1: like why do they pair up and how that helps
Speaker 1: him flow through the material. The reason they pair up
Speaker 1: is that they essentially they deform the lattice in this
Speaker 1: in the same way, so like they're moving through the
Speaker 1: lattice together. There's grid of atoms, and you know, think
Speaker 1: of the lattice like you might think of like a mattress, right,
Speaker 1: like on your bed um. If you sit down in
Speaker 1: the mattress, it makes a depression in it. Right, If
Speaker 1: somebody else sits on the mattress, it also makes a depression.
Speaker 1: And which way are you most likely to roll? Right?
Speaker 1: If there's a depression on the mattress another one next
Speaker 1: to it that you're gonna lean in towards the center,
Speaker 1: unless you have like a really awesome, very expensive mattress.
Speaker 1: But making one depression makes it makes you attracted to
Speaker 1: the next depression, right, And so that's what kind of
Speaker 1: brings the electrons together m exactly. They sort of shake
Speaker 1: the lattice in this way that makes them more likely
Speaker 1: to be closer to each other than further apart. And
Speaker 1: it has to be cold, because if the whole bed
Speaker 1: is shaking and moving, you know, this effect is not
Speaker 1: gonna matter. Be careful. Pretty soon we're gonna be doing
Speaker 1: analogies involving dancing and beds, and you know where that's
Speaker 1: going to go. Dirty dancing. Yeah, keep your dancing vertical here, folks,
Speaker 1: I see where are you going with that key pokey?
Speaker 1: So the electrons are moving through the lattice, and they
Speaker 1: like to stay together. This is a very small attractive
Speaker 1: force that keeps them in pairs. You know, it doesn't
Speaker 1: they don't like it's not like they're you know, it's
Speaker 1: a snow particle with a minus to charge or anything.
Speaker 1: They're just sort of like grouped together as they move
Speaker 1: through the lattice um and because the electrons by themselves
Speaker 1: are fermions, things that don't like to share states, but
Speaker 1: together they're bosons, then they act differently. If you heard,
Speaker 1: for example, of liquid helium. Liquid helium is a super fluid.
Speaker 1: It's something that can flow without any resistance. And the
Speaker 1: reason is that helium is a boson, right, the atom
Speaker 1: itself is a boson, and and when it gets really
Speaker 1: really cold, they can flow without resistance. And so electrons
Speaker 1: are kind of like that. When they get really really cold,
Speaker 1: they pair up, and these cooper pairs are boson, so
Speaker 1: they can share states just like liquid helium atoms, and
Speaker 1: they can then they can slide through the lattice with
Speaker 1: with basically zero resistance. It's sort of incredible. It's kind
Speaker 1: of like individually, there's this this this whole mess of
Speaker 1: atoms blocking their way. But once they pair up, it's
Speaker 1: almost like the laws of physics. They're operating under a
Speaker 1: different instead of laws of physics almost, And so then
Speaker 1: suddenly the highway opens up in front of him. Yeah,
Speaker 1: it's like following somebody through a dance floor is easier
Speaker 1: than going through the dance floor yourself. Right, And so
Speaker 1: two people moving through the dance floor together sort of
Speaker 1: orbiting around each other a little bit can just sort
Speaker 1: of make the other dancers move out of their way
Speaker 1: just the right way for them to slip through without
Speaker 1: feeling any resistance. It's like crowdsurfing exactly. It's like crowdsurfing,
Speaker 1: and it's a subtle effect. You know. This attraction between
Speaker 1: the electrons is small, and so it took people a
Speaker 1: long time to understand. There are a lot of crazy
Speaker 1: ideas that people had to explain super connectivity, most of
Speaker 1: which were wrong. And this one crazy idea which turned
Speaker 1: out to be true. And so that's why they have
Speaker 1: to be cold to so that there's sort of m
Speaker 1: room for these electronicity to get together. That's right. Super
Speaker 1: connectivity was discovered in materials like ten or twenty degrees kelvin,
Speaker 1: and as we said, that's necessary to have the regular
Speaker 1: lattice and to have this thing happened. Um. And also,
Speaker 1: this attraction between the electrons is very fragile, and so
Speaker 1: if things are too hot, then that attraction is really
Speaker 1: is hard to make. And so for a long time
Speaker 1: people thought, well, superconductors are cool, they have cool applications.
Speaker 1: But jeez, if you've got to be twenty degrees kelvin,
Speaker 1: that's not very practical. You know, you're not gonna have
Speaker 1: the wires in your house being twenty degrees kelvin. That's
Speaker 1: super cold. Okay, let's get into the different flavors of superconductors,
Speaker 1: but first let's take another break. All right, So, Daniel,
Speaker 1: you were telling me that there are different flavors of superconductors,
Speaker 1: like super duper conductors, and well, they're all super conductors,
Speaker 1: but they're made in different ways, different kinds of materials.
Speaker 1: So for like fifty years, there are only a few
Speaker 1: superconductors that were known. But then in the eighties, probably
Speaker 1: described by this magazine article you read, there was a breakthrough.
Speaker 1: People found superconductors that could work at real tie high temperatures,
Speaker 1: you know, up to like maybe between thirty and a
Speaker 1: hundred degrees kelvin. That's still super cold. I mean, I
Speaker 1: think parts of Canada might be a hundred degrees calenright now.
Speaker 1: And these are like metals or I think I read
Speaker 1: they're ceramics, right, They're they're not just all metals. There's
Speaker 1: some of them are ceramics. Yeah, some of them are
Speaker 1: ceramics exactly, which really surprised people. Um, but they can
Speaker 1: do super connectivity at fairly high temperatures, you know, versus
Speaker 1: thirty degrees and then fifty degrees in the sixty degrees,
Speaker 1: and these days they're up above a hundred degrees kelvin,
Speaker 1: which is still pretty cold, but it's it's getting closer
Speaker 1: to like the liquid nitrogen level, where you can get
Speaker 1: something cold pretty cheaply. If you eat something down like
Speaker 1: ten degrees levin, you have to have super world class
Speaker 1: refrigeration and liquid helium, which is all very hard. You
Speaker 1: only need something pretty cold. You can use liquid nitrogen,
Speaker 1: which is cheap and easily available and so maybe practical. Yeah,
Speaker 1: now you can just go down to the store and
Speaker 1: pop open a bottle of liquid nitrogen. That's right. And
Speaker 1: this is a pretty exciting field because every few years,
Speaker 1: like a new kind of materials discovered that can do
Speaker 1: super conductivity at a higher temperature. It's like every five years,
Speaker 1: and I'm just like, hey, look, I zapped this with
Speaker 1: this new kind of goo, and I smeared peanut butter
Speaker 1: on it and dunked it into good nungrogen and fried
Speaker 1: in the microwave, and look now it's a superconductor. I
Speaker 1: think your colleagues are probably regretting having talked to you
Speaker 1: at this point. Probably, I mean not literally, they're not
Speaker 1: actually using peanut butter, but they are just exploring wacky
Speaker 1: stuff and sometimes they're surprised, like there's an amazing kind
Speaker 1: of superconductor that uses these graphene sheets, right, this really
Speaker 1: weird arrangement of carbon. And if you take two of them,
Speaker 1: two sheets, and you twist one at just the right angle,
Speaker 1: then the sheets together can act like a superconductor. And
Speaker 1: you were saying that these high temperature superconductors, they're the
Speaker 1: ones that we don't really understand. Yeah, because remember, to
Speaker 1: have superconducting materials, you need these cooper pairs to move
Speaker 1: through the materials, so you need their electrons to be
Speaker 1: attracted to each other somehow. But that attraction is very,
Speaker 1: very very low, and so if the material is hot,
Speaker 1: then that attraction is basically nothing compared to the energy
Speaker 1: of the electrons and the energy of the lattice. And
Speaker 1: so it's hard to understand how that works. And there
Speaker 1: are a lot of smart people working right now on
Speaker 1: theories of high temperature superconductors, and you know, they have
Speaker 1: some tools that have good simulations that can describe this
Speaker 1: and describe that, but it's not as far advanced as
Speaker 1: the theories of low temperature superconductors. And that's important because
Speaker 1: we'd like to predict, like, hey, will this material be
Speaker 1: a superconductor or what materials should we make in order
Speaker 1: to have superconductors that work at room temperature? That's the
Speaker 1: final goal. And so nobody really understands how these works.
Speaker 1: And it's kind of hard because you can't just sort
Speaker 1: of sort of like poke it right, you can just
Speaker 1: sort of open it up and look look at what's
Speaker 1: going on. You you have to kind of use theory
Speaker 1: and simulations. Yeah, exactly. It's a complicated problem. Um, but
Speaker 1: it's really interesting. You know. People love making new kinds
Speaker 1: of stuff and trying to get it to do weird
Speaker 1: things and understanding these mysteries. Um, I think it's really fun.
Speaker 1: These guys have a lot of fun building these simulations
Speaker 1: and thinking about it. And you know, I asked them like,
Speaker 1: do you think there will ever be room temperature superconductors?
Speaker 1: And nobody wants to say yes, because that's predicting the future.
Speaker 1: But there is a lot of confidence because every few
Speaker 1: years we get a new kind of superconductor that's warmer
Speaker 1: than any of the others. And so if that continues,
Speaker 1: you know, another few decades, we might get superconductors that
Speaker 1: are at fairly warm temperatures. It's all about finding the
Speaker 1: right recipe exactly. It's finding the right recipe, the right
Speaker 1: kind of ingredients, mix them in the right kind of ways,
Speaker 1: app them with the right kind of laser, all this
Speaker 1: kind of stuff. Do a dance a certain way, exactly,
Speaker 1: you gotta do the dance. Okay. So that's that's super
Speaker 1: conductors and how they work. Um, but this sort of
Speaker 1: their biggest application is kind of not really in conducting electricity.
Speaker 1: It's more in magnets, right, and making super magnets. That's right.
Speaker 1: Of course, there's a connection because how do you bank
Speaker 1: an electromagnet? Right? How do you make a magnet that
Speaker 1: you can turn on and off? But you do that
Speaker 1: by having something which conducts electricity. You make a loop
Speaker 1: of current, because a loop of current will make a magnet.
Speaker 1: And so if you have something which can do super
Speaker 1: conducting electronics, then you can have current flowing through it
Speaker 1: at a really high rate and it doesn't heat up
Speaker 1: and and break down. Or anything, and so you can
Speaker 1: get really strong magnets. Oh, lets you um make magnets
Speaker 1: that you can turn on and off. It's like a yes,
Speaker 1: electric magnets, Yeah, electromagnets. You can turn them on and off.
Speaker 1: You can dial their strength up and down, which is
Speaker 1: really important for a particle collider. And if you use
Speaker 1: superconductors then you can there's no resistance and so you
Speaker 1: can really get really strong magnets. Yeah exactly. And you
Speaker 1: want really strong magnets that are pretty small. They don't
Speaker 1: take you know, they aren't like the size of a
Speaker 1: school bus or something. So you want them to be powerful.
Speaker 1: You want them to be small, and that's what we
Speaker 1: need at the particle collider. And also you want super
Speaker 1: strong magnets for other things like who doesn't want to
Speaker 1: ride in a magnetically levitating train that would be also right.
Speaker 1: The others are the magleft ones in Japan, right, Yeah exactly.
Speaker 1: And um, so the stronger the magnets, the easier that
Speaker 1: technology is, the more practical that technology is. Right and so, um,
Speaker 1: superconductors play a lot of role in making really strong magnets.
Speaker 1: But then also very directly, you know you want superconductivity,
Speaker 1: Well it would be great to have in your transmission lines.
Speaker 1: Like we were saying earlier, your electricity would be cheaper
Speaker 1: if you could get it straight from the power station
Speaker 1: without losing any energy. Right, they lose a significant fraction
Speaker 1: in the energy they generate just in sending it to us.
Speaker 1: Oh my gosh. So if you can, Yeah, if you
Speaker 1: find a recipe for a room temperature superconductor, you would
Speaker 1: revolutionize everything. Right, you would be a zillionaire and you
Speaker 1: could just dance all night and not have to worry
Speaker 1: about anything ever again, seriously, that would be a zillion
Speaker 1: dollar invention. Temperature superconductors, like you would you would haven't
Speaker 1: elect a grid with no loss like your you know,
Speaker 1: your phone wouldn't heat up and lose energy. Yeah. Plus
Speaker 1: it would be a fascinating mystery of physics, like how
Speaker 1: does that happen? How is it possible? Um? I love
Speaker 1: when we can create stuff that we don't understand because
Speaker 1: it gives us like a concrete hook into some mystery
Speaker 1: of the universe, something that says, there's something here that
Speaker 1: will teach you a lesson, there's some insight here waiting
Speaker 1: for you to discover. And of course there could be
Speaker 1: insights anywhere. You never know. But when you have something
Speaker 1: physical that you don't understand, you know there's an insight there.
Speaker 1: There's like a concrete clue you can follow up, you know.
Speaker 1: So to me, that's very exciting. Wow. Yeah, alright, Well,
Speaker 1: I think that we can safely conclude that superconductors have
Speaker 1: to do with conductors and force and stuff and dance
Speaker 1: and dancing. So we have danced our way through this topic,
Speaker 1: and we hope that you enjoyed it and that you
Speaker 1: now understand a little bit more about superconductivity. So go
Speaker 1: out there and find a pair to dance with. And
Speaker 1: they don't necessarily have to be called Cooper, that's right,
Speaker 1: And they even can have the same charge. Right. Sometimes
Speaker 1: times opposites attract, sometimes electrons attract. Oh my goodness, how
Speaker 1: many times can we dance around this punt? I don't know.
Speaker 1: I think we're breaking down. We'll break dancing pruct a
Speaker 1: dance all right, guys, Thanks for joining us, See you
Speaker 1: next time, See you next time. If you still have
Speaker 1: a question after listening to all these explanations, please drop
Speaker 1: us a line. We'd love to hear from you. You
Speaker 1: can find us at Facebook, Twitter, and Instagram at Daniel
Speaker 1: and Jorge that's one word, or email us at feedback
Speaker 1: at Daniel and Jorge dot com