What Is A Superconductor?

How does a super conductor work?

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Episode Transcript

Speaker 1 (00:07):
Hey, Daniel, When you think of physics, what images come
to mind for you? I think of the cosmos, I
think of planets. I think of the fire inside the sun.
I think of crazy people with weird hair when you
look in the mirror. When you think of physics, what's
the difference? Well, what about a dance party. I wouldn't

(00:31):
say that's in the top one thousand associations I have.
Might maybe not even in the top five thousand. Well,
it turns out that physics and dance actually have a
lot in common. They have a lot of fun connections.
Is that right? Yeah, they can help us understand the
topic of our podcast to day. That's right. Thinking about
the way people dance and the way they shake their
booty could actually help you understand the physics, the crazy

(00:53):
topic of today's podcast. So get out there, shake your
and get ready to download some physics into your brain.
Get into the groove. It's time for physics. Hi'm h

(01:24):
and I'm Daniel. Welcome to our podcast, Dancing with Physicists.
How far can you get across the universe by just dancing? Now?
We're just kidding. You were not the victim of clickbait.
This is the podcast Daniel and Jorge explain the universe,
in which we take something weird, something fascinating in the
universe and try to explain it to you, sometimes using
dance to be on the podcast, we're going to talk

(01:46):
about a physics phenomenon that is everywhere. It's everywhere, and
it's helping make some of the greatest scientific experiments in
the world. That's right. It's really important, it's fascinating, it's weird,
it's quantum, and yet it's not really very well understood.
And more most important, it's super that's right. And it conducts.

(02:10):
Uh what, it's conductive. There you go, that's right. The
topic of today's podcast is super conductors. What are they?
Who are they? Who are they? Super? No? Super conductivity
is fascinating question, something behind a lot of really interesting

(02:33):
research in the last few decades, and something we thought
was worth getting into because there's a lot of puzzles there. Yeah.
I was just thinking, the first time I heard about
super conductors was in the eighties, right, and let's when
it sort of became this big buzz about it. That's right.
They had a lot of big advances in the eighties.
How old were you in the eighties? Or I was

(02:54):
old enough apparently to read about science news, but but
you would always see it tied to the to this
footage of this little magnet floating on top of something. Yeah,
that's like a classic application of super conductivity. Yeah. Yeah, so,
like I think forever, that's what people think of a
lot of people think of when they think of super conductors,
like that one image. Yeah, there's that. There's also the

(03:16):
super conducting super collider that they were going to build
in Texas in the nineties that was going to cost
a huge amount of money and that they canceled halfway through.
And so a lot of people connect those two phrases
super conducting and super colliding. Oh yeah, no, I didn't
hear about that one in the eighties. Um, So it
sort of seems like it's been out there in the

(03:37):
popular culture for a while, and but we were wondering
how much people knew about it, and you know, it's
part of the popular culture and the people maybe have
heard about it or whatever. It's strangely, it hasn't really
entered like, um, you know, um comic books or science
fiction that much. You don't see like super conducting technology
all over the place in science fiction. I mean, you

(03:58):
haven't seen that comic called The super Conductor Adventures of
Crime Fighting super Conductor. That's right, During the day, he's
just a mild mannered, regular bus conductor, but at night
he's a super duper conductor. No, I haven't seen that,
and you don't see it. Um. You know, playing a
prominent role in science fiction movies like particle physics is

(04:21):
everywhere in science fiction movies. The Higgs boson explains everything
and causes problems, etcetera. But you don't see super conductivity
used and abused much in popular culture. Do you have
I missed it? Yeah, I don't know. I guess it's
not flashy, right, it's not um. It's not a word
that sounds as cool as quantum or leasers or higgs boson. Yeah, exactly. Yeah. Anyway,

(04:43):
so I went around campus and I asked people, do
you know what super conductivity is? Can you explain it?
Do you understand it? Here's what people had to say.
What about super conductivity? Have you heard of that? Yes?
Can you explain that? Best? Guess maybe it has two
conductors and for some stuff. Okay, uh, yeah, I've also

(05:07):
heard of it, but I also have no idea either. Okay, Um,
it's a phenomena that happens at very low temperatures because
electrons have very low resistance to movement due to the
very slow vibrations of the matrix of the metal of
the nucleus of the atom, so the electrons have a

(05:28):
lot more space to move through. Something along those lines.
Is that the one with the magnets and they could float.
That's about all I know about that one where no
I can guess though, Um, my conductivity with like wires,
for example, or like metal so super conductive, then it's
a good conductor, doesn't burn out. I would assume that

(05:50):
it has something to do with objects that are conductive. Alright, Yeah,
so I like the person who said that it has
something to do with conductors and force and stuff. That's right.
And there's somebody out there who clearly is reading the
same magazine you were, because they're like, oh, it has
to do with magnets that can float. Yeah, yeah, do

(06:11):
you know which clip I'm talking about? I feel like
they used the same clip for years and years and
years and years and years. Yeah. I totally know what
you mean. A little black magnet floating over a very
cool surface. With like liquid hydrogen sublimating off of it.
It's pretty cool looking. And then somebody comes and pokes
the magnet and it just keeps floating there. Yeah, exactly exactly.
So people had some sense, you know, they knew what

(06:32):
it was. Nobody was like, I've never heard that word before,
what are you talking about? Right, But nobody could explain
it to me. Like some people knew you had to
be cold to be a superconductor, but nobody could give
me a solid explanation for what it was and how
it worked. Right. I guess this one has something understandable,
which is a conductor, and you know, I guess people
in high school figure out that or learned that it's

(06:54):
something that conducts electricity, and so a super conductor must
just be something that is super ad That's right, it's
awesome at conducting extracity. Right, that should be the next discovery.
Awesome conductors. That's right. Superconductors last year, this year, awesome
conductors next year, uber conductors. Um. But there is really

(07:14):
something special about superconductors, which is not just that they
can conduct a lot, but that they conduct with no
resistance at all, where that you can't have anything better
than a superconductor. So it is pretty amazing, and they
are really important for things like particle physics, right, Yeah,
they have a lot of really cool applications. So it's
like a physics phenomenon that has really great applications for

(07:39):
important experiments like the Large Hadron collider. That's right, And
it's also a really fun physics puzzle. You know. The
kind of physics that I do personally is like take
everything apart and understand the smallest bits. That's totally worthwhile
obviously and leads to deep insights. But there's a whole different,
other kind of way of doing physics that's like can
we put things together in a weird way that makes

(07:59):
weird materials? You know, we have lots of materials around
us on Earth that we're familiar with, but you can
think like can we rearrange those bits to make new
kinds of stuff. So there's a whole group of people
out there in physics departments because basically all their job
is is to make new kinds of goo, right, Like,
let's mix this together and add a little bit of
that and a little bit of this, and maybe if
we zap it with a laser will get this weird

(08:21):
crystal with strange behaviors that like nothing anybody's ever seen before.
Are you talking about solid state physics? Yeah? These days
I think they call it condensed matter physics. But essentially, yeah,
it's like, can we build new kinds of stuff? It's
like the properties of bulk materials, you know, UM, not
individual particles, but like what happens when you put all
these different kinds of particles together in a certain lattice

(08:44):
and a certain in a certain arrangement. Do they behave
in strange ways? And what can we learn about you know,
what solids can and cannot do, right, because they do
different things right, Like, you can make things behave in
a totally different, a new way just by the way
you arrange them. Yeah, and you know, the periodic table
is the first lesson of that. Everything in the periodic
table is made out of the same bits, right, protons

(09:06):
and neutrons and electrons, but they're pretty different, right. Uranium
is pretty different stuff than lithium, for example, And so
you can get an incredible variety of behaviors just by
rearranging the same stuff. And so solid state physics, that
whole field UM is just taking that to in extremes
like how can we combine these elements and zap them
and chill them and heat them and do all sorts

(09:26):
of crazy stuff. It's basically like cooking, right, what kind
of cakes can you make with the same ingredients right
that that taste totally different exactly and can float above
your countertop? Right? Super connecting cakes, that's the next breakthrough.
This is just renaate that department stuff physics, physics, stuff,
physics of stuff. Yeah, exactly, the physics of stuff. Hey,

(09:48):
stuff is pretty interesting. Rights, the whole podcast called stuff.
You should know how stuff works? Then we should join
that podcast network. I think there's stuffed pretty full cool.
So let's get into it all right, um, and let's

(10:09):
break it down. So let's what's a superconductor. Let's start
with just the conductor part. Dig in a little bit
into what it means to be a conductor, right, So,
a conductor is something where electricity can move through it, right,
And you have to understand the electricity moving through it
is not necessarily the same as like electrons flowing through it.
You put the electricity on one side of a of

(10:31):
a wire and you get electricity on the other side
of the wire. It's tempting to think about it like
a hose, like you put water on one side and
water comes out the other side. Like a tube. Yeah,
like a tube. And you know what happens is you
put electrons in on one side and the electrons all
sort of shift over like it's it's like a tube
full of water. You put a little bit of water
in the front, and a little bit of a different

(10:52):
piece of water that was already in there pushes out
the side. It's kind of like um, if you have
a two and you blow in it. The air that
comes out the the end is not necessarily the air
they came out of your mouth. It's like it causes
some sort of it pushes all the air through and
the ones that come out are the ones that we're
waiting closest to the end exactly. And that's only possible
if the electrons can move. Right. And so a conductor

(11:15):
is just any material where you have electrons that can
jump from atom to atom. Right. Think about a material
and a microscopic scale, it's really a bunch of atoms, right,
And if it's simple or regular, then it's like a
lattice like a grid, and it's like regularly distributed atoms,
and the electrons can jump from one to the other.
So if you blow on one side, you like pushing
about some electrons on one side, then all the electrons

(11:38):
sort of hop over one slot and you get some
out the other side. It's kind of like, um, like
playing hot potato. Yeah exactly. And the difference between something
that can conduct electricity a conductor, and something that can't,
an insulator, is that conductors have enough electrons that can
jump between atoms, whereas insulators have all their electrons held

(11:58):
really tight by each of those atoms in the grid,
so that there's no way for the electrons to jump
from one to the other. Conductors have these free electrons
that are sort of just like floating around happily. Okay,
So it's something that is not a conductor doesn't have
kind of a spare electrons, or they don't they don't
let electrons fly around freely. Yeah exactly. And so and

(12:22):
you just you know, you put electrons on one side
and they just go nowhere, right, So you can't get
electrons through the material. Okay, so wait, wait, why not?
So I introduce an electron in an insulator and something
that doesn't conduct what's going to happen to the electron?
It won't go through, yeah, it just it won't cause
a current. Right, you can't get a current through there.
You can't get all the electrons to jump over one
atom for example. Okay, so it's kind of like, Um,

(12:45):
a conductor has a bunch of atoms, and everyone kind
of has everyone's pretty loose with their electrons. That's right. Okay,
here's one. Oh, I'll take one. R I'll give you
another one. Oh. Um, electrons can just kind of flow
through from atom to atom. Yeah, And it's best to
think of them really as a lattice, because these atoms
individually act a little different than they do when they're
together in a material. And when they're together in a material,

(13:07):
the electrons slash easily back and forth between them. Um,
for a conductor, for an insulator, that doesn't happen. And
then of course there's lots of different kinds of conductors
that things that are good conductors and things that are
bad conductors. And by a lattice, you mean like a
like a grid or like a like a rack, Like
the electrons are arranged kind of like um in rows

(13:28):
and in columns, right, Yeah, exactly. If you zoom in
on a crystal, for example, or a piece of metal,
anything that has a regular arrangement of the atoms, you'll
see that they're organized in this in this pattern right there,
built out of these basic units, and that they're pretty regular.
You know, there's like lines of atoms. Um, it's not
just like a big heaping mess. Right. Um, These these solids,

(13:48):
these metals, these things that are conductors are pretty well organized,
and so you'll see them in rows and and uh.
And that's what we mean by the lattice. You have
just like a grid of atoms. And so you're saying
like us can flow through or jump freely between atoms,
but not perfectly right, that's right. And here's where the
temperature comes in. So, Um, the colder the material is.

(14:11):
Think about what temperature really is. What is temperature? It's
how much the atoms inside something are wiggling. The atoms
inside liquid are wiggling more than the atoms inside of solid, right,
which is why it's liquid, and the atoms inside of
gas are totally free and bouncing around everywhere. But even
inside of solid, even if it's solid, you have different temperatures. Right,
You can have a piece of metal that's hot or
piece of metal that's cold. What's happening there is that

(14:34):
the atoms are moving less, right, They're wiggling less, and
as it gets colder and colder, they wiggle less and
less and less. And this is important for the electron
because remember, it's trying to jump from atom to atom.
That's easier when the atoms are not wiggling around, when
they're like regularly spaced rows, like when they're frozen in place. Yes, exactly.
Here's where the dance analogy comes in. Right. Imagine trying

(14:55):
to walk through a crowd and everybody's like jumping. It's
like a mosh pit, right, and they're going crazy into
punk consider or something. It's really hard to get across
the crowded room if everybody's jostling and bouncing and moving
around a lot, Right, It's much easier if they're calm,
if they're like, you know, slow dancing or something. It's
kind of like, yeah, you would. If it's a marsh
pit and everyone's moving and dancing, you would just kind

(15:18):
of lose a lot of energy just kind of bumping
against people and just trying to make it through. Exactly.
You would lose a lot of energy. That's exactly right.
It's the resistance, right. So electrical resistance is electrons losing
energy as they bump into the atoms that are wriggling
around because they're moving like. It's related to the kinetic
motion of the atoms. Yeah, absolutely, it's related to the

(15:39):
kinetic motion of the atoms. It makes it harder for
the electrons to get through and as they get through,
they lose some energy. Right. Okay, so that's resistance, right,
that's um vehicles. The resistance of a wire or a conductor,
that's what it is. It's it's like electrons going through
but sort of bumping too much into the atoms. That's it.

(16:00):
And so things that are conductors have low resistance, and
you want to use things that have low resistance so
that most of the energy you're sending along a wire,
for example, gets there. And if you use something with
low resistance like copper or gold, then most of the
energy you put into a wire will get to the
other side. If you use something with really bad resistance,
with a lot of resistance, then it will heat up
the wire. That energy from the electrons will create resistance,

(16:22):
which turns into heat and that's not good. But sometimes
you sort of want resistance, right, Like in circuits, some
resistors are sometimes good. Yeah, sometimes you want resistance so
you can put it in on purpose. For example, a
light bulb, that's a resistor, right. What it does is
it steals the energy from the electrons and it heats
of the material, which then glows and gives you light.
Awesome if that's what you wanted, right, But you don't

(16:44):
really want them wires in your house glowing. You want
them to transmit that energy to your iPhone or whatever
it is you're sending. And those power lines along the road, right,
we don't want those heating up and melting. Want those
to transmit the energy from the power station to your
house without losing much energy. Unless you your house is
a dance floor, that would be pretty cool, Like, well,

(17:08):
how are you going to power those speakers without the electrons? Well,
the speakers will glow too. Sounds like an awesome party,
Send me an invite. And I think that brings us
to the cool point, which is that the resistance of
a conductor depends on the temperature. Yeah, exactly, So as
it gets colder, the lattice, this grid of atoms gets

(17:28):
more regular, and it gets easier for the electrons to
get through, and so the resistance goes down with temperature.
So hot wire is harder to get electrons through it
because all the apps are are moving more. But a
cold wire lets the electrons flow easy, more easy. That's right,
all right, cool, that's that's a conductor, not somebody who

(17:48):
drives a bus or directs an orchestra. That person is
also a conductor. Yeah, but is he a superconductor? Is
he resistant? Does he glow? Does he steal energy from
innocent electrons? All right, that's a conductor, And now let's
get into superconductors. But first let's take a quick break,

(18:21):
all right, Daniel, So it fills in what is a
super conductor and what is so super about them? Superconductors
are really pretty super. The thing that makes them super
is that they have zero resistance, not just like very small,
not like Ebsalon resistance, but zero, like zero point zero
zero zero zero. Keep going with the zeros there, man,

(18:42):
because it's zero all the way. Okay, Yeah, it's pretty crazy.
It means that, for example, if you had a loop
of super connecting wire, you could put a current into
it and it would just zoom around it forever. It
would like never get used up. It's a pretty hard
concept to imagine. It's like, it's like living in a
world without friction. And you know, it's like imagine you
had a sheet of ice, you pushed a block on it, right,

(19:05):
you expect it to go for a while and then
eventually slow down because every surface has some friction. But
what if you had a perfectly smooth surface with no
resistance and you pushed it, it would just go forever.
It's like a perpetual motion machine. Yeah, sort of like that.
Or is it kind of like if you if you're
out in space and you start spinning something a top,

(19:28):
It's just going to keep spinning for a long time
because there's nothing there's no air, no resistance, no nothing
to stop it from spinning. That's right, yeah, exactly. And
so a superconductor is something that has zero resistance and
so the electrons can just flow right through it. It's
pretty amazing, all right. So let's get into how that works.
And I think what's cool I heard is that physicists

(19:50):
don't really know what's going on. Yeah, well, there's some
there are different kinds of superconductors, and some of them
are pretty well understood, the old fashioned ones, the classic ones.
But rees they've made a bunch of really strange superconductors
um that nobody really understands in great detail. I mean,
we have some simulations we can describe it, but a
lot of it's just too complicated or like write down

(20:11):
equations on paper that we can understand. Okay, So there's
different flavors of superconductors. Yeah, the first thing they all
have in common is that you've got to get it cold.
Like we were saying earlier, you want to lower the
resistance first, get it cold, and so chill that thing down.
And people built refrigerators to get things down to like
really really really cold temperatures like ten or twenty degrees kelvin.

(20:33):
You know, that's like just above absolute zero. And and
the point is that one gets colder that cold, the
grid in the material stops moving, it stops vibrating, right,
that's right. And you can't get anything down to actually
absolute zero, but you can get it down really really cold,
and the grid stops vibrating, as you say, and then

(20:55):
it gets easier and easier for electrons to go through,
and so that will bring you down to low resistant,
even very low. Some might even say super low, but
it won't get you all the way down to zero resistance. Oh,
I see, if you just had a regular like if
I took a copper wire and I froze it to
almost zero kelvin, it would give me pretty low resistance,

(21:15):
but not necessarily zero resistance. I don't actually know if
copper can become a superconductor, but I just mean that
chilling it down is not the all the explanation. To
explain how something loses its resistance. You need more than
just understanding that it gets colder and therefore it's easier
for the electrons to go through. You need there's another
piece of the explanation. There's some extra magic going on there,

(21:38):
some extra dance magic. Yeah, exactly, because physics, if you
just think about the temperature physics as you shouldn't have superconductors,
but we do have them. It was in the early
part of the twentieth century that people made superconductors and
observed it, and people thought, what, how is this even possible?
And then the theorists spend decades thinking about it and
trying to come up with explanations like we know this exists, right,

(21:59):
this one favorite things in science when we have something
we know it exists, but we don't know how it
can work, Like it doesn't seem like it should be possible.
Yet here we have one. And then one night they
went dancing and they figured it all out. That's right.
They were getting knocked over in the mosh pit, and
when they woke up from their concussion, they had a
brilliant idea. Well, that's that's kind of the analogy here, right, Like, Um,

(22:23):
if you're this is a dance party and there's a
mosh bit and people are jumping and going crazy, it'd
be really hard to go through it. But if you
suddenly turn out the music and everyone did the manne
Can challenge, it would be a lot easier to walk
through it. But it wouldn't be perfectly easy to go through.
You still might bump into people, rub against people, and

(22:45):
so the resistance would be low, but not zero. That's right.
So to get down to zero and took a really
clever bit of thinking boy theorists to explain how this
could work. And it comes down to a concept called
Cooper pairs. And the short version of the explanation is
that lecture don't go through individually, they gather together into
pairs like you know, like pair dancing, um, like you know,

(23:06):
square dancing or waltzing or whatever. Oh my goodness, the
dance analogies don't stop. Why should they write? It's a
dance party to the end of time? Um, and going
through in pairs they can accomplish actually zero resistance, okay,
so um, it's sort of related to some quantum effects, right, Like,
at some point to get to zero resistance, you need

(23:28):
that sort of quantum magic to make an up. Yeah,
which is really awesome because it's really fun when quantum
mechanics is not just like hidden under the rugs, some
tiny little effect that only affects tiny particles, when it
actually gives you a macroscopic thing that you can measure,
that you can see, you can prove. Look, quantum mechanics
is real and this is an example of that. And
to understand it, a little bit of quantum mechanics you

(23:50):
need to know is just that electrons are a certain
kind of particle we call them fermons, and that kind
of particle doesn't like to share. It doesn't like to
be in the same state as another kind of article.
So you can't have two electrons both occupying, for example,
the lowest rung on the energy ladder of an atom.
They don't like to be in the same one. So
this one already there, the next one will feel the
second rung, and the next one will feel the third rung.

(24:12):
They don't all like to hang out together on the
bottom rung, right, Usually they like to dance solo. That's right, exactly.
They all think they're the best dancer ever Ene danced
by themselves in the Dance Lord. But what happens when
you get two of them together is that they act
like the other kind of quantum particle. We call those bosons,
And bosons are totally happy to pile up on top

(24:33):
of each other and they can occupy the same state,
no big deal. Maybe you've heard of a Bose Einstein condensate.
That's an example of a bunch of bosons getting really
really cold and all sitting in exactly the same quantum state,
the lowest energy state, and then they all act together
and do really weird quantum effects. We should do a
whole podcast on the Bosonstein condensate. That's pretty cool stuff.

(24:54):
But there's something going on because normally electrons don't like
to pair up like this, But when you cool down
a superconductor, suddenly it becomes possible and even preferable for
them to pair up. Yeah. Well, electrons are both negatively charged, right,
and so they don't like to hang out with each other.
They repel each other quite a bit. But you only
need a very slight attraction this. These Cooper pairs are

(25:17):
not like they're not like really bound tightly together, just
sort of like loosely associated. You know, they're like two
people eyeing each other across the dance floor, sending signals
back and forth. So can you describe the effect here,
like why do they pair up and how that helps
him flow through the material. The reason they pair up
is that they essentially they deform the lattice in this
in the same way, so like they're moving through the

(25:39):
lattice together. There's grid of atoms, and you know, think
of the lattice like you might think of like a mattress, right,
like on your bed um. If you sit down in
the mattress, it makes a depression in it. Right, If
somebody else sits on the mattress, it also makes a depression.
And which way are you most likely to roll? Right?
If there's a depression on the mattress another one next
to it that you're gonna lean in towards the center,

(26:00):
unless you have like a really awesome, very expensive mattress.
But making one depression makes it makes you attracted to
the next depression, right, And so that's what kind of
brings the electrons together m exactly. They sort of shake
the lattice in this way that makes them more likely
to be closer to each other than further apart. And

(26:20):
it has to be cold, because if the whole bed
is shaking and moving, you know, this effect is not
gonna matter. Be careful. Pretty soon we're gonna be doing
analogies involving dancing and beds, and you know where that's
going to go. Dirty dancing. Yeah, keep your dancing vertical here, folks,
I see where are you going with that key pokey?

(26:51):
So the electrons are moving through the lattice, and they
like to stay together. This is a very small attractive
force that keeps them in pairs. You know, it doesn't
they don't like it's not like they're you know, it's
a snow particle with a minus to charge or anything.
They're just sort of like grouped together as they move
through the lattice um and because the electrons by themselves

(27:11):
are fermions, things that don't like to share states, but
together they're bosons, then they act differently. If you heard,
for example, of liquid helium. Liquid helium is a super fluid.
It's something that can flow without any resistance. And the
reason is that helium is a boson, right, the atom
itself is a boson, and and when it gets really

(27:32):
really cold, they can flow without resistance. And so electrons
are kind of like that. When they get really really cold,
they pair up, and these cooper pairs are boson, so
they can share states just like liquid helium atoms, and
they can then they can slide through the lattice with
with basically zero resistance. It's sort of incredible. It's kind
of like individually, there's this this this whole mess of

(27:52):
atoms blocking their way. But once they pair up, it's
almost like the laws of physics. They're operating under a
different instead of laws of physics almost, And so then
suddenly the highway opens up in front of him. Yeah,
it's like following somebody through a dance floor is easier
than going through the dance floor yourself. Right, And so
two people moving through the dance floor together sort of

(28:14):
orbiting around each other a little bit can just sort
of make the other dancers move out of their way
just the right way for them to slip through without
feeling any resistance. It's like crowdsurfing exactly. It's like crowdsurfing,
and it's a subtle effect. You know. This attraction between
the electrons is small, and so it took people a
long time to understand. There are a lot of crazy

(28:35):
ideas that people had to explain super connectivity, most of
which were wrong. And this one crazy idea which turned
out to be true. And so that's why they have
to be cold to so that there's sort of m
room for these electronicity to get together. That's right. Super
connectivity was discovered in materials like ten or twenty degrees kelvin,
and as we said, that's necessary to have the regular

(28:57):
lattice and to have this thing happened. Um. And also,
this attraction between the electrons is very fragile, and so
if things are too hot, then that attraction is really
is hard to make. And so for a long time
people thought, well, superconductors are cool, they have cool applications.
But jeez, if you've got to be twenty degrees kelvin,
that's not very practical. You know, you're not gonna have
the wires in your house being twenty degrees kelvin. That's

(29:17):
super cold. Okay, let's get into the different flavors of superconductors,
but first let's take another break. All right, So, Daniel,

(29:38):
you were telling me that there are different flavors of superconductors,
like super duper conductors, and well, they're all super conductors,
but they're made in different ways, different kinds of materials.
So for like fifty years, there are only a few
superconductors that were known. But then in the eighties, probably
described by this magazine article you read, there was a breakthrough.
People found superconductors that could work at real tie high temperatures,

(30:01):
you know, up to like maybe between thirty and a
hundred degrees kelvin. That's still super cold. I mean, I
think parts of Canada might be a hundred degrees calenright now.
And these are like metals or I think I read
they're ceramics, right, They're they're not just all metals. There's
some of them are ceramics. Yeah, some of them are
ceramics exactly, which really surprised people. Um, but they can

(30:22):
do super connectivity at fairly high temperatures, you know, versus
thirty degrees and then fifty degrees in the sixty degrees,
and these days they're up above a hundred degrees kelvin,
which is still pretty cold, but it's it's getting closer
to like the liquid nitrogen level, where you can get
something cold pretty cheaply. If you eat something down like
ten degrees levin, you have to have super world class

(30:42):
refrigeration and liquid helium, which is all very hard. You
only need something pretty cold. You can use liquid nitrogen,
which is cheap and easily available and so maybe practical. Yeah,
now you can just go down to the store and
pop open a bottle of liquid nitrogen. That's right. And
this is a pretty exciting field because every few years,
like a new kind of materials discovered that can do

(31:03):
super conductivity at a higher temperature. It's like every five years,
and I'm just like, hey, look, I zapped this with
this new kind of goo, and I smeared peanut butter
on it and dunked it into good nungrogen and fried
in the microwave, and look now it's a superconductor. I
think your colleagues are probably regretting having talked to you
at this point. Probably, I mean not literally, they're not
actually using peanut butter, but they are just exploring wacky

(31:26):
stuff and sometimes they're surprised, like there's an amazing kind
of superconductor that uses these graphene sheets, right, this really
weird arrangement of carbon. And if you take two of them,
two sheets, and you twist one at just the right angle,
then the sheets together can act like a superconductor. And
you were saying that these high temperature superconductors, they're the

(31:46):
ones that we don't really understand. Yeah, because remember, to
have superconducting materials, you need these cooper pairs to move
through the materials, so you need their electrons to be
attracted to each other somehow. But that attraction is very,
very very low, and so if the material is hot,
then that attraction is basically nothing compared to the energy
of the electrons and the energy of the lattice. And

(32:07):
so it's hard to understand how that works. And there
are a lot of smart people working right now on
theories of high temperature superconductors, and you know, they have
some tools that have good simulations that can describe this
and describe that, but it's not as far advanced as
the theories of low temperature superconductors. And that's important because
we'd like to predict, like, hey, will this material be
a superconductor or what materials should we make in order

(32:30):
to have superconductors that work at room temperature? That's the
final goal. And so nobody really understands how these works.
And it's kind of hard because you can't just sort
of sort of like poke it right, you can just
sort of open it up and look look at what's
going on. You you have to kind of use theory
and simulations. Yeah, exactly. It's a complicated problem. Um, but
it's really interesting. You know. People love making new kinds

(32:52):
of stuff and trying to get it to do weird
things and understanding these mysteries. Um, I think it's really fun.
These guys have a lot of fun building these simulations
and thinking about it. And you know, I asked them like,
do you think there will ever be room temperature superconductors?
And nobody wants to say yes, because that's predicting the future.
But there is a lot of confidence because every few
years we get a new kind of superconductor that's warmer

(33:13):
than any of the others. And so if that continues,
you know, another few decades, we might get superconductors that
are at fairly warm temperatures. It's all about finding the
right recipe exactly. It's finding the right recipe, the right
kind of ingredients, mix them in the right kind of ways,
app them with the right kind of laser, all this
kind of stuff. Do a dance a certain way, exactly,

(33:33):
you gotta do the dance. Okay. So that's that's super
conductors and how they work. Um, but this sort of
their biggest application is kind of not really in conducting electricity.
It's more in magnets, right, and making super magnets. That's right.
Of course, there's a connection because how do you bank

(33:55):
an electromagnet? Right? How do you make a magnet that
you can turn on and off? But you do that
by having something which conducts electricity. You make a loop
of current, because a loop of current will make a magnet.
And so if you have something which can do super
conducting electronics, then you can have current flowing through it
at a really high rate and it doesn't heat up

(34:16):
and and break down. Or anything, and so you can
get really strong magnets. Oh, lets you um make magnets
that you can turn on and off. It's like a yes,
electric magnets, Yeah, electromagnets. You can turn them on and off.
You can dial their strength up and down, which is
really important for a particle collider. And if you use
superconductors then you can there's no resistance and so you

(34:38):
can really get really strong magnets. Yeah exactly. And you
want really strong magnets that are pretty small. They don't
take you know, they aren't like the size of a
school bus or something. So you want them to be powerful.
You want them to be small, and that's what we
need at the particle collider. And also you want super
strong magnets for other things like who doesn't want to
ride in a magnetically levitating train that would be also right.

(35:01):
The others are the magleft ones in Japan, right, Yeah exactly.
And um, so the stronger the magnets, the easier that
technology is, the more practical that technology is. Right and so, um,
superconductors play a lot of role in making really strong magnets.
But then also very directly, you know you want superconductivity,
Well it would be great to have in your transmission lines.
Like we were saying earlier, your electricity would be cheaper

(35:24):
if you could get it straight from the power station
without losing any energy. Right, they lose a significant fraction
in the energy they generate just in sending it to us.
Oh my gosh. So if you can, Yeah, if you
find a recipe for a room temperature superconductor, you would
revolutionize everything. Right, you would be a zillionaire and you
could just dance all night and not have to worry

(35:46):
about anything ever again, seriously, that would be a zillion
dollar invention. Temperature superconductors, like you would you would haven't
elect a grid with no loss like your you know,
your phone wouldn't heat up and lose energy. Yeah. Plus
it would be a fascinating mystery of physics, like how
does that happen? How is it possible? Um? I love

(36:07):
when we can create stuff that we don't understand because
it gives us like a concrete hook into some mystery
of the universe, something that says, there's something here that
will teach you a lesson, there's some insight here waiting
for you to discover. And of course there could be
insights anywhere. You never know. But when you have something
physical that you don't understand, you know there's an insight there.
There's like a concrete clue you can follow up, you know.

(36:30):
So to me, that's very exciting. Wow. Yeah, alright, Well,
I think that we can safely conclude that superconductors have
to do with conductors and force and stuff and dance
and dancing. So we have danced our way through this topic,
and we hope that you enjoyed it and that you
now understand a little bit more about superconductivity. So go

(36:51):
out there and find a pair to dance with. And
they don't necessarily have to be called Cooper, that's right,
And they even can have the same charge. Right. Sometimes
times opposites attract, sometimes electrons attract. Oh my goodness, how
many times can we dance around this punt? I don't know.
I think we're breaking down. We'll break dancing pruct a

(37:16):
dance all right, guys, Thanks for joining us, See you
next time, See you next time. If you still have
a question after listening to all these explanations, please drop
us a line. We'd love to hear from you. You

(37:36):
can find us at Facebook, Twitter, and Instagram at Daniel
and Jorge that's one word, or email us at feedback
at Daniel and Jorge dot com