Speaker 1: How does the universe work? What are the rules that
Speaker 1: govern its most microscopic nature. For a few hundred years,
Speaker 1: we've been making progress on this question, mostly by taking
Speaker 1: things apart, and when we zoom into the universe at
Speaker 1: the smallest level, it seems so far like there are
Speaker 1: two different categories of particles, matter particles like quarks and electrons,
Speaker 1: and force particles like photons and gluons. For a long time,
Speaker 1: it seems like that has to be all there is.
Speaker 1: What else could there possibly be? But experiments aren't the
Speaker 1: only way to reveal the secrets of the universe. Another
Speaker 1: very fruitful path is to follow the math. When we
Speaker 1: ask what else the math allows, we sometimes get predictions
Speaker 1: for very weird phenomena like antimatter, or black holes or
Speaker 1: Higgs bosons, which turn out to be real in the universe.
Speaker 1: So can the math show us another kind of particle?
Speaker 1: A weird third way beyond matter and forces. Welcome to
Speaker 1: Daniel and Kelly's Extraordinary mathematical Universe.
Speaker 2: Hello, I'm Kelly Wiersmith. I study parasites and space, and
Speaker 2: I think there are four kinds of particles.
Speaker 3: Are parasites the fourth particle?
Speaker 2: I mean if physics were any good, the answer would
Speaker 2: be yes. See what I think is that y'all like symmetry,
Speaker 2: and I think that if you decide there's three kinds
Speaker 2: of particles, that will be an odd number and you'll
Speaker 2: have to decide there's another kind, so that it's even Hi.
Speaker 3: I'm Daniel.
Speaker 1: I'm a particle physicist, not a paraparticle physicist or a
Speaker 1: parasitical particle physicist or any.
Speaker 3: Those other varieties.
Speaker 1: But I do love understanding the nature of the universe
Speaker 1: and finding symmetry in.
Speaker 2: It all amazing. So are you one of those physicists
Speaker 2: who feels like there needs to be symmetry in these
Speaker 2: answers or does it just kind of depend on the topic?
Speaker 1: Wow, what a deep question to drop on me at
Speaker 1: the top of the episode. I think what we've learned
Speaker 1: so far is that there is symmetry in the universe.
Speaker 1: Like all the rules we've discovered about physics seem to
Speaker 1: follow symmetric patterns. There's like reflections and translations, and you
Speaker 1: can generalize this into abstract algebra called group theory. So
Speaker 1: the universe seems to be well described by symmetries in mathematics.
Speaker 1: Does that mean the universe is symmetric or that's just
Speaker 1: the way we like to think about it. I mean,
Speaker 1: that's a deep question in philosophy. We're not going to
Speaker 1: answer it today. But I appreciate symmetry.
Speaker 3: I love it. I love the mathematical beauty of what
Speaker 3: we've learned about the universe.
Speaker 2: Why should the universe be symmetrical instead of like just
Speaker 2: a mess? Like as an evolutionary biologist, like it all
Speaker 2: being held together with like duct tape and zip ties
Speaker 2: makes more sense to me then it being beautifully symmetrical.
Speaker 2: But why is it symmetrical?
Speaker 1: I think I have a natural preference for explanations that
Speaker 1: are simple, that are harmonious and parsimonious, right, Like we
Speaker 1: think that the universe should be in the end described
Speaker 1: by one simple idea, and so we're constantly looking for that,
Speaker 1: and symmetry helps us restrain that. It helps us reduce
Speaker 1: the number of options, you know, like instead of having
Speaker 1: to come up with ten numbers, what if there's a
Speaker 1: symmetry that tells you that those numbers are all related,
Speaker 1: so there really is just one number that turns into ten.
Speaker 1: But you might also ask the basic question like, well,
Speaker 1: why do we expect the universe to be simple and parsimonious,
Speaker 1: and I don't have an answer for that, you know,
Speaker 1: just so far that seemed to work, you know, looking
Speaker 1: for the simplest explanation so far has found us things
Speaker 1: that work in the universe. They predict experiments, they describe
Speaker 1: things we haven't seen yet. So many times in the
Speaker 1: history of science we followed the symmetry in mathematics to
Speaker 1: make discoveries like particles or like electromagnetism. You know, Maxwell
Speaker 1: looking at these equations and seeing a lack of symmetry
Speaker 1: and penciling in the piece he needs to make the
Speaker 1: equation symmetrical, discovering something real in the universe, or Peter
Speaker 1: Higgs finding a piece that clicks together with all the
Speaker 1: other pieces to answer why symmetry is broken, so it
Speaker 1: seems to work, is the only real answer I can
Speaker 1: give you.
Speaker 2: Interesting, you know, So I was I'm reading this book
Speaker 2: called The Remedy right now, and it is about how
Speaker 2: like Coch and Pasteur determined that microorganisms caused disease. And
Speaker 2: the author was arguing that actually this kind of flew
Speaker 2: in the face of we should look for the simplest answer,
Speaker 2: because the simplest answer at the time was that bad
Speaker 2: air causes all of these maladies, and so having one
Speaker 2: cause that explained all of this stuff seemed much simpler
Speaker 2: than you know, Tuberculosis is caused by this tiny organism,
Speaker 2: and smallpox is caused by that tiny organism that we
Speaker 2: can't even see. And so the fact that bad air
Speaker 2: was simple a sort of made people cling to it
Speaker 2: a little bit longer than this more complicated answer that
Speaker 2: tended to be right. And so I think in almost
Speaker 2: every case it makes a lot more sense to look
Speaker 2: for the simplest explanation first, but you should not let
Speaker 2: it close your eyes to the more complex answers that
Speaker 2: might actually be the reality of the situation.
Speaker 1: Yeah, you should choose the simplest answer that works, that
Speaker 1: actually describes the universe. Yes, not the simplest answer that
Speaker 1: doesn't describe the universe. But you're right, you don't know
Speaker 1: in advance what's going to work and what isn't, And
Speaker 1: so we often start from the simplest thing because why
Speaker 1: not right, And if that doesn't work, then we move
Speaker 1: on to something more complicated.
Speaker 3: And that's how we get chemistry and biology and.
Speaker 1: All sorts of other delicious, beautiful messes of science. Right,
Speaker 1: that have yet to pull themselves together into a single
Speaker 1: parsimonious explanation. And that's also one reason why I am
Speaker 1: a physicist, because physics, I feel like, is closer to
Speaker 1: getting to a single answer than chemistry is. For example,
Speaker 1: I was always frustrated in chemistry, like this rule for
Speaker 1: this thing, and this rule for that thing, and this
Speaker 1: other rule except for this other scenario. Maybe I just
Speaker 1: have a bad memory and it's hard to hold all
Speaker 1: those things in my head. But I just really like
Speaker 1: to look, here's one equation. Start from that you can
Speaker 1: get to anything. That just always appealed to me.
Speaker 2: That's so interesting. I think we live on very different
Speaker 2: sides of this gradient. So like for me, you know,
Speaker 2: you said biologists and chemists have yet to come up
Speaker 2: with a simple theory. I don't feel like that's what
Speaker 2: we're trying for at all.
Speaker 1: Like why maybe that's why you haven't found one.
Speaker 2: Why would you assume that there is one? Like life
Speaker 2: is beautifully complex, you know, the it depends is where
Speaker 2: all the fun lives. I think. You know, you're like, oh,
Speaker 2: that's frustrating, and I'm like, no, that's that's the exciting part.
Speaker 2: Like what it depends on what life is complicated and
Speaker 2: messy and that's what makes it beautiful.
Speaker 1: But isn't it beautiful when you find things that are
Speaker 1: true across all of life? Right Like DNA, for example,
Speaker 1: undergirds a lot of life on Earth, and that's really
Speaker 1: powerful to discover that and to understand it. Right, Yeah,
Speaker 1: it's not as fascinating as like this one kind of
Speaker 1: frog does this one kind of thing on random tuesdays
Speaker 1: in my opinion.
Speaker 2: Well, I will politely disagree with you. I think what
Speaker 2: the frogs are doing on tuesdays I am deeply interested in.
Speaker 2: But yes, you know, I think it's beautiful that you know,
Speaker 2: the blueprint for life is stored in the same material
Speaker 2: no matter what organism you're looking at. But we all
Speaker 2: do very different things with that material. You know, bacteria
Speaker 2: do horizontal gene transfer. They're swapping genes back and forth,
Speaker 2: and you know, we have to have sex to swap
Speaker 2: genetic material, and we've got recombination and I don't know anyway,
Speaker 2: that's where the it depends gets fun again.
Speaker 1: Well, we have made a lot of hay in physics,
Speaker 1: at least in looking for symmetries and then trying to
Speaker 1: understand when there are holes, is there something to fill
Speaker 1: that hole? Right the way we did with antiparticles and
Speaker 1: the way we did with all the quarks, and so
Speaker 1: often mathematical beauty really does lead us to new discoveries.
Speaker 1: And that's what we're talking about today on the podcast.
Speaker 1: Whether there is another bucket, another kind of thing out
Speaker 1: there in the universe that we can use to describe
Speaker 1: how everything works, maybe explains why those toads do that thing.
Speaker 3: On Tuesday, at.
Speaker 2: The end of all of our banters, I'm like, how
Speaker 2: are we going to get back on track? And you
Speaker 2: always get us there.
Speaker 1: Okay, it's sometimes a bigger step than I expect.
Speaker 4: But.
Speaker 2: You're good at jumping that chasm. So all right. So
Speaker 2: today we're talking about paraparticles and I had never heard
Speaker 2: of para particles before, and so let's see if our
Speaker 2: audience is on the same page as Kelly. So we asked,
Speaker 2: what are para particles? And here are the answers we got.
Speaker 4: I wonder if it's something to do with larger things
Speaker 4: showing particle light behavior in certain circumstances. I'm so glad
Speaker 4: there isn't. TONI exam at the end of the podcast.
Speaker 2: Piece of a particle, like a very small part of
Speaker 2: the particle, some sort of entity that exists alongside the
Speaker 2: traditional particles.
Speaker 3: Somewhere between a real particle and a ghost particle, like
Speaker 3: a virtual particle, and then it's enabling interactions with others.
Speaker 4: I think it's like a super superposition. And it's one
Speaker 4: of those weird things about quantum mechanics that if you
Speaker 4: look at it, it just disappears off.
Speaker 2: I might be particles that we believe exist but haven't
Speaker 2: I prayed for yet.
Speaker 3: Kind of like a particle but not quite.
Speaker 2: Something that acts like a particle when certain conditions are.
Speaker 3: Met at something that's almost a particle. Paraparticles rely on
Speaker 3: their neighboring particle for existence. I'm completely stunned by this one.
Speaker 2: The virtual particle pairs that spring to existence in a vacuum.
Speaker 2: Is a paraparticle something that lives off of or takes
Speaker 2: advantage of another particle?
Speaker 3: Is it a paralyzed particle?
Speaker 2: So lots of playing with what para means in other contexts.
Speaker 2: I like it got you all are very clever.
Speaker 1: But they missed the obvious. Nobody went for the connection
Speaker 1: to parasites.
Speaker 2: Guys, Guys, I work so oft hard so hard. Oh wait, no, no, no,
Speaker 2: that's not true. Somebody said, relying on their neighbors for existence,
Speaker 2: that's their parasitical particles. That's right way to go, that
Speaker 2: particular audience member. Thank you for paying attention all this time.
Speaker 1: I was just glad that nobody went for the sort
Speaker 1: of anti academic grifter line, the like academics are just
Speaker 1: parasites on society and they're sucking money and scams and
Speaker 1: don't really believe anything they're doing, all that bad faith
Speaker 1: nonsense you sometimes see in various corners of the internet.
Speaker 2: Oh wow, are you I feel like there's a bit
Speaker 2: of insecurity today.
Speaker 1: I just want to address the reality, you know, that
Speaker 1: kind of stuff is out there in the universe. Anyway,
Speaker 1: I was very happy to hear all these positive and
Speaker 1: constructive answers. Thanks everybody. If you'd like to contribute your
Speaker 1: ideas for future episodes, don't be shy right to us
Speaker 1: two questions at Daniel and Kelly dot org. You can
Speaker 1: hear your voice on the podcast.
Speaker 2: Amazing. All right, So let's dig in. So what are
Speaker 2: a particle? So you said in the introduction that there
Speaker 2: are maybe three kinds of particles. Can we start by
Speaker 2: reviewing the first two kinds, because I'm sure that you've
Speaker 2: mentioned in the past that particles come in matter and
Speaker 2: force flavors. But every once in a while, at the
Speaker 2: end of an episode, I'll discover my brain has reached
Speaker 2: capacity and maybe some stuff overflowed out the top, and
Speaker 2: so remind me what are meta particles? What are force particles?
Speaker 2: And then we'll get into this third kind.
Speaker 3: Yeah, sure, no problem. I'd be careful with the word flavor.
Speaker 1: Though flavor has a particular meaning in particle physics, it
Speaker 1: means something else, and it's not like you know, cookie
Speaker 1: dough and mint chocolate chip. It's like the difference between
Speaker 1: electrons and muons and towels or different flavors of leptons.
Speaker 2: Like that's an actual like physics jargon term is flavors.
Speaker 1: Oh absolutely, And there's amazing the whole subfield of particle
Speaker 1: physics called flavor physics. And then the people who work
Speaker 1: on the flavor of particles that have a lot of mass,
Speaker 1: that's called heavy flavor physics, which sounds like it should
Speaker 1: be a hip hop group, but it really is a
Speaker 1: bunch of nerds.
Speaker 2: Well, you know, nerds can have hip hop groups. You
Speaker 2: don't have to be so judgy.
Speaker 3: Yeah, heavy flavor flakes, let's hear it.
Speaker 2: I love it.
Speaker 3: All right.
Speaker 1: So today we're talking about one way to distinguish particles,
Speaker 1: and that's by their spin. So there are particles that
Speaker 1: make up matter, me and you, and everything that's out
Speaker 1: there and everything you've ever eaten are made out of
Speaker 1: quarks and lectons. So the upcork and the down cork
Speaker 1: make up protons and neutrons. You add electrons, which are
Speaker 1: kind of lefton, and you can make any atom. Right
Speaker 1: from that, you can make any molecule. And anything anybody
Speaker 1: has ever seen or thrown at their sister is made
Speaker 1: out of this kind of stuff, right, Okay, So this
Speaker 1: is what we call matter particles. And all these particles
Speaker 1: have something in common, which is their quantum spin has
Speaker 1: units of one half, which means they can have spin
Speaker 1: up one half or spin down one half. So all
Speaker 1: these particles, which we call fermions after Enrico Fermi, these
Speaker 1: are matter particles. They're particles with one half spin.
Speaker 2: Can you help me like visualize that, like, are they
Speaker 2: actually spinning?
Speaker 1: M You know the answer to that question, Kelly is
Speaker 1: nobody knows. Quantum spin is a super fascinating topic because
Speaker 1: on one hand, it's very different from a real spin,
Speaker 1: like normal spin, like you take a ball and you
Speaker 1: spin it. We can talk about the angular momentum, we
Speaker 1: can talk about the velocity on the surface. A classical
Speaker 1: object has spin and it has angular momentum, right, And
Speaker 1: we know that that angler momentum is important to the
Speaker 1: universe because it's preserved. Like if you spin a ball
Speaker 1: in space, it keeps spinning. And the reason that like
Speaker 1: our galaxy is spinning is because of conservation of angular momentum.
Speaker 1: The reason the solar system has the shape that it does,
Speaker 1: it's like sort of flat. The way the galaxy is
Speaker 1: a disc is because of angle momentum. Anglementum is a
Speaker 1: really big important thing in the universe. Things really do spin.
Speaker 1: Quantum particles don't spin in the same way because electrons
Speaker 1: are not tiny little balls. And like one hundred years ago,
Speaker 1: when they were thinking about this, they were like, well,
Speaker 1: what if they spin, how fast would they be spin?
Speaker 1: They try to calculate, like how fast the surface of
Speaker 1: an electron is spinning, and you get an answer that's
Speaker 1: like higher than the speed of light. So it's obviously nonsense.
Speaker 1: Whenever you do physics and you get an answer that
Speaker 1: doesn't make sense, like something has gone wrong along the
Speaker 1: way right.
Speaker 2: Or you've created a new field.
Speaker 1: In this case, the answer is that these are quantum particles.
Speaker 1: They're not classical, so you can think of them as
Speaker 1: existing physically the same way, where every part of them
Speaker 1: has a location every moment in time, so they don't
Speaker 1: physically spin. You shouldn't think about these quantum particles as
Speaker 1: like little balls that are spinning, and so you might ask, well,
Speaker 1: if it's not spinning, why do you call it spin.
Speaker 1: We call it spin because it has a lot of
Speaker 1: the same properties as classical objects spin. For example, it's
Speaker 1: conserved right, and it's conserved together with other kinds of
Speaker 1: angular momentum, meaning that what the universe cares about is
Speaker 1: the total angler momentum, including spin. So you can convert
Speaker 1: like normal angler momentum like the Earth is spinning, into
Speaker 1: quantum angle momentum spin, and back and forth. The universe
Speaker 1: requires you to conserve the sum of those two, which
Speaker 1: tells you they're like the same kind of thing the
Speaker 1: same way that like energy is often conserved, but it's
Speaker 1: the sum of kinetic and potential energies. Which tells you like, Okay,
Speaker 1: these are two kinds of the same thing, because what
Speaker 1: the universe cares about is the sum of them, not
Speaker 1: the individual ones. So we know that quantum spin is
Speaker 1: similar to real spin classical spin because the universe conserves
Speaker 1: the sum of those things, and quantum spin has other
Speaker 1: similar properties, like things that have quantum spin and electric
Speaker 1: charge have little magnetic fields because charges in motion give
Speaker 1: magnetic fields. So like an electron which is spinning, has
Speaker 1: a little magnetic field, and that's why it's like bent
Speaker 1: by magnetic fields, et cetera, et cetera. So we don't
Speaker 1: really know what it is, but we know that it
Speaker 1: acts a lot like spin, so we call it quantum spin,
Speaker 1: which I think is a pretty good name, even though
Speaker 1: it's not spinning.
Speaker 2: Okay, all right, So I usually to hear things like
Speaker 2: four times before they stick in my brain. I think
Speaker 2: we're at like two, so be prepared to repeat that.
Speaker 2: But so to try to help me, all right, So, fermions,
Speaker 2: these are the mass or the matter particles. Yes, and
Speaker 2: so I'm gonna think of fermions as like it's firm matter.
Speaker 2: It makes us be although you know now you're gonna
Speaker 2: misspell fermions from here on out because it's not spelled
Speaker 2: like firm. But anyway, all right, that's how I'm remembering it.
Speaker 2: And so now let's talk about force. And so I
Speaker 2: always thought force was like a field, and I didn't
Speaker 2: think of it as a particle anyway. So let's go on.
Speaker 2: So the bosons are force particles.
Speaker 1: Yes, And let me also liabrate on the comment you
Speaker 1: made about field versus particles. There are two ways of
Speaker 1: thinking about what stuff is and how it's pushed. One
Speaker 1: is the field picture, which is really natural to a
Speaker 1: lot of particle physicists. There's an electron field, and the
Speaker 1: electron is actually just a ripple in that field, and
Speaker 1: there's an electromagnetic field, and photons are ripples in that field.
Speaker 1: And in that view, the fields are the fundamental thing,
Speaker 1: and particles are just ripples in those things. They are
Speaker 1: like emerging phenomena from the fields, and the fields can interact.
Speaker 1: And we talk about that picture a lot on the podcast.
Speaker 1: There's another way to think about things and say, you know,
Speaker 1: fields are just like a construct in our minds. We
Speaker 1: never see them directly. We only see them acting on particles,
Speaker 1: and the particles are the things we can see. We
Speaker 1: see dots on the screen, we see electrons moving through wires, etc.
Speaker 1: So particles are the real things. And so from that
Speaker 1: point of view, we have electrons and they're little particles,
Speaker 1: and we have quarks and their little particles, and then
Speaker 1: the forces we can talk about other particles. So we
Speaker 1: have like the photon. What happens when two electrons repel
Speaker 1: each other, they exchange photons. So this is the particle
Speaker 1: picture of the universe. Everything is made out of little particles,
Speaker 1: and it can explain matter. It's a little bit more awkward,
Speaker 1: but it can also explain forces right in that picture,
Speaker 1: like electrons exchange photons. That's the way they attract or
Speaker 1: repel each other. And it's a little bit awkward because
Speaker 1: like how exactly they do electrons and positrons attract each
Speaker 1: other by exchanging photons.
Speaker 3: It's hard to imagine you.
Speaker 1: Could like attract Zach by throwing a ball at him, right,
Speaker 1: it feels like it would only push him away. But
Speaker 1: you know, this is the quantum world, and you can
Speaker 1: do weird things like you can throw a photon with
Speaker 1: negative momentum, so when Zach catches it, he's pulled towards you.
Speaker 1: It's like a tractor beam photon.
Speaker 2: And biology is too complicated, doesn't make sense. What are
Speaker 2: you guys thinking?
Speaker 1: Yeah, yeah, And this is one reason why I think
Speaker 1: the field picture is a little bit more natural.
Speaker 3: But anyway, we can.
Speaker 1: Talk about these forces as mediated by particles. And these
Speaker 1: particles have a property which is that they don't have
Speaker 1: half integer spin like one half or negative one half.
Speaker 1: They have integer spin. So a photon, for example, can
Speaker 1: have spin one, spin zero or spin negative one. And
Speaker 1: the W boson and the Z boson, and the Higgs
Speaker 1: boson and the gluons, all the particles that correspond to
Speaker 1: the forces and how matter particles exchange momentum, they all
Speaker 1: have the same property that their spin is integer values,
Speaker 1: you know, half it's like plus two minus one, this
Speaker 1: kind of stuff. So those are particles we call bosons.
Speaker 1: So the fermions and the matter particles, the bosons are
Speaker 1: the force particles in this picture.
Speaker 2: All right, So now we've got through the two kinds
Speaker 2: of particles, and let's bring a little bit of pep
Speaker 2: into this conversation after the break, So we'll talk about
Speaker 2: the Paul exclusion principle when we get back all right,
Speaker 2: So we've established that we have two kinds of particles.
Speaker 2: We've got the fermions, which are the matter particles, and
Speaker 2: the bosons, which are the force particles. Why does it
Speaker 2: matter that we divide them in this way? Why can't
Speaker 2: they all just be particles.
Speaker 1: They are all just partticles or fields equivalently, but they
Speaker 1: have very different behaviors, and that behavior is really important. Specifically,
Speaker 1: bosons can do something fermions will never ever ever do,
Speaker 1: which is, bosons can be in the same quantum state
Speaker 1: and fermions never will. So you made this joke about PEP.
Speaker 1: The poly exclusion principle, named after Wolfgunning Poll says that
Speaker 1: no two fermions can ever be in the same quantum state.
Speaker 1: So if you have two identical particles like two electrons,
Speaker 1: they can't have all the same quantum description, which would
Speaker 1: be like their location, their momentum, their spin, their energy,
Speaker 1: all this kind of stuff. They can't be identical. They
Speaker 1: have to be unique. Every fermion has to have a
Speaker 1: different quantum state.
Speaker 2: Does it make sense to think of that? So our
Speaker 2: fermions are our matter particles. Does it make sense to
Speaker 2: think of it as like two pieces of matter can't
Speaker 2: take up the same space. Or this is like a
Speaker 2: totally different thing than thinking about it that way.
Speaker 1: Two pieces of matter can't up the same space as
Speaker 1: long as they have something to differentiate them. So, for example,
Speaker 1: electrons have two possible spins right, spin up and spin down.
Speaker 1: So in the ground state of an atom, for example,
Speaker 1: you can have two electrons with exactly the same energy,
Speaker 1: the same momentum, the same location, the same energy, the
Speaker 1: same everything, but one is spin up and the other
Speaker 1: is spin down. That's why you have two electrons in
Speaker 1: the lowest state. That's where that two comes from. Because
Speaker 1: there are two options for spin. You can't have two
Speaker 1: electrons both spin up, and you can't have two electrons
Speaker 1: both spin down.
Speaker 3: Because of this poly.
Speaker 1: Exclusion principle, it says you can never have two electrons
Speaker 1: in the same state, and that's why you don't get
Speaker 1: all of the electrons in the ground state. If you
Speaker 1: already have two electrons in that ground state, it's full.
Speaker 1: It can't take anymore. There's no third spin right, So
Speaker 1: when another electron comes along, it has to have a
Speaker 1: higher energy, has to be in the next energy level
Speaker 1: because the lowest rungs are filled and it's one electron
Speaker 1: per unique state, right, So the lowest energy level has
Speaker 1: two of those. The next one, because has more energy,
Speaker 1: has more options for like where the electron it is
Speaker 1: around the atom this p state. Now we're getting deep
Speaker 1: into chemistry, some beyond my expertise right away. But that's
Speaker 1: why you can have more electrons in that second one,
Speaker 1: and then more in the third level and more in
Speaker 1: the fourth because there's more options for differentiating exactly which
Speaker 1: version of that energy level you're in. And this is
Speaker 1: why we have chemistry. This is why gold looks the
Speaker 1: way it does. This is why we have water, this
Speaker 1: is why atoms bind together. This is why our whole
Speaker 1: universe looks the way that it does, because fermions cannot
Speaker 1: be in the same state.
Speaker 2: Now, is this an observation of what's happening or do
Speaker 2: we understand why it has to be that way.
Speaker 1: It's still a little bit mysterious, Like, it's definitely an
Speaker 1: observation and we've never ever seen it violated. And if
Speaker 1: it was violated, like the whole universe would look different,
Speaker 1: Like if somebody turned this rule off and said, hey, fermeons,
Speaker 1: no problem. You can now share a state. All of
Speaker 1: matter would collapse.
Speaker 2: Bad news exactly, it would.
Speaker 1: Be bad news. So I don't recommend it. If you're
Speaker 1: sitting in the Universe control room and you have your
Speaker 1: finger on that knob, call me please before you do anything.
Speaker 1: We do have some handwavy explanations for why it is.
Speaker 1: We don't have a really full formal proof. We can't
Speaker 1: go from like, here are the fields, here's how Fermions
Speaker 1: will behave. What we can do is prove the negative,
Speaker 1: like we can show why Fermions can't do this thing,
Speaker 1: Like we can show that if Fermions did this thing,
Speaker 1: it would lead to some contradictions. So I'm trying to
Speaker 1: walk you through a handwavy version of that proof in
Speaker 1: a minute. But we couldn't have started from scratch and
Speaker 1: really shown how this happens. And Fineman famously said that
Speaker 1: we don't have a full proof, and also it's really
Speaker 1: challenging to give an intuitive explanation for this because quote,
Speaker 1: we do not have a complete understanding of the fundamental
Speaker 1: principle involved. Finan was big on this theory that like,
Speaker 1: if you can't explain it simply, you don't really understand it,
Speaker 1: which I think is really interesting as a hypothesis because
Speaker 1: it kind of lines up with what we were talking
Speaker 1: about earlier, and it touches on something we were talking about,
Speaker 1: I think on the discord of like how on this
Speaker 1: pod we're constantly trying to explain complicated stuff in an
Speaker 1: intuitive way. Without all the math. You can't just be like,
Speaker 1: here's a bunch of math. This math tells you what
Speaker 1: the answer is. We want to tell a story that
Speaker 1: connects with the ideas in your head, so you go, oh,
Speaker 1: that makes sense.
Speaker 3: I get it.
Speaker 1: Why it's this way and not the other way. And
Speaker 1: that's very different from the mathematical explanation or concepts that
Speaker 1: we often have in academia and we teach in college
Speaker 1: and in graduate school, and that most physicists have in
Speaker 1: their minds. This is like an intuitive grasp of something
Speaker 1: you have to develop in order to explain it and
Speaker 1: find me is saying that without that extra piece, this
Speaker 1: like parallel explanation, that's intuitive, you don't really understand it.
Speaker 1: And I think that's fascinating and maybe correct. But it's
Speaker 1: a pretty strong statement of philosophy for a guy who
Speaker 1: was famously against philosophy.
Speaker 2: Yeah, and how do you think he would feel about
Speaker 2: the current state of things today. Although I'm gonna go
Speaker 2: ahead and admit that I hate questions where they're like,
Speaker 2: what do you think Benjamin Franklin would think about blah
Speaker 2: blah blah. It's like, I'm not Benjamin Franklin, and if
Speaker 2: he was raised in our time, you might feel totally
Speaker 2: different about things.
Speaker 1: Yeah, Feineman is a complicated character because, on one hand,
Speaker 1: super genius dude, lots of important insights, also lots of
Speaker 1: great explanations, and he did something which I think is
Speaker 1: really impressive that I've never seen before, which is he
Speaker 1: came up with an explanation of or a concept in
Speaker 1: this case Nuther's theorem in one of his popular books,
Speaker 1: like for a popular Audience, and that explanation then got
Speaker 1: transformed into a full rigorous proof, which is now the
Speaker 1: go to rigorous proof you find in like formal physics books.
Speaker 1: Usually things go the other way, you like, start with
Speaker 1: a full rigorous proof and then you develop the intuitive explanation.
Speaker 1: But he actually came up with it for the general
Speaker 1: public and then it turned into a rigorous proof, So
Speaker 1: that's pretty cool. Like, the guy definitely had talents and
Speaker 1: lots of different directions. He's also famously kind of a jerk,
Speaker 1: and so it's sort of a problematic figure in that sense.
Speaker 1: I think if finally we're a lot today, he probably
Speaker 1: would feel grumpy that people had come up with stuff
Speaker 1: without him.
Speaker 3: Great, I don't know Hardy.
Speaker 2: Well, he's in our past. He's in the rear view mirror. Okay.
Speaker 2: So we have observed that fermions don't occupy the same state.
Speaker 2: We kind of understand why it would be nice to
Speaker 2: understand better.
Speaker 1: And we've observed that bosons can, right. We see this
Speaker 1: all the time. Like you put two photons in a box,
Speaker 1: they're very happy to sit right on top of each
Speaker 1: other to be in exactly the same state. And this
Speaker 1: lets you do things like make Bose Einstein condensates and
Speaker 1: macroscopic objects that have quantum properties because all the photons
Speaker 1: are in the same state, and you can't do that
Speaker 1: with electrons. You put too many electrons together, they get
Speaker 1: this degeneracy pressure. They don't want to be in the
Speaker 1: same lowest state, so some of them have to be
Speaker 1: in a higher energy state, and that's where you get
Speaker 1: like pressure. That's why like white dwarves don't collapse because
Speaker 1: the electrons inside them if they collapse would have to
Speaker 1: end up being in the same lower energy state, and
Speaker 1: they resist that they can't do it, and so like,
Speaker 1: this has real impact in the universe, and it affects
Speaker 1: how we do experiments and all sorts of stuff. And
Speaker 1: so this is definitely real and we have some understanding
Speaker 1: of how it.
Speaker 3: Works, all right.
Speaker 2: So fermions are our introverts and the bosons are our extroverts.
Speaker 1: Electrons just want to be in their own house, like
Speaker 1: watching their own TV show at night by themselves, and
Speaker 1: photons are always up for a party.
Speaker 2: Okay, So now we have a pretty good understanding of
Speaker 2: fermions and bosons and what they can and can't do.
Speaker 2: How do we get from here to paraparticles?
Speaker 3: All right?
Speaker 1: So to understand how paraparticles might fit into this picture,
Speaker 1: because it sounds like there are only two options. Either
Speaker 1: you have half into your spin, you know, one half,
Speaker 1: three halves, five halves, or you have into your spin
Speaker 1: zero one, two, three, whatever. What's another option? How could
Speaker 1: you possibly have a third category?
Speaker 3: Right?
Speaker 1: And that was the prevailing wisdom for a long long
Speaker 1: time until very recently. But to understand where the loophole is,
Speaker 1: we've got to dig one level deeper into understanding why
Speaker 1: fermions behave this way and why bosons behave the other way.
Speaker 1: So we're going to go through this sort of rough
Speaker 1: and imperfect proof of the poly exclusion principle to explain
Speaker 1: why fermions behave one way and bosons the other way.
Speaker 2: Daniel's got pep, All right, let's do that.
Speaker 1: All right, So imagine two particles, particle one and particle two.
Speaker 2: In typical physicist fashion. Those are very boring names for them, but.
Speaker 1: Okay, okay, let's make them exciting names.
Speaker 3: What would be exciting names for these particles? Now?
Speaker 2: Feeling if we name them like Frank and Rita, it's
Speaker 2: gonna be hard to keep track. Maybe one and two
Speaker 2: was a good idea.
Speaker 1: Okay, wow, that doctor criticism pretty quickly there. Alright, alright, alright,
Speaker 1: so particle boring one in particle boring.
Speaker 2: Two, all right.
Speaker 1: Now, each of them can do one thing, right now,
Speaker 1: They have two different options. They can be in state
Speaker 1: A or state B. Okay, so particle A can do
Speaker 1: two things. It can be in state A or it
Speaker 1: can be in state B. Particle two can also be
Speaker 1: in state A or state B. And then we can
Speaker 1: describe the full quantum state of the pair of the
Speaker 1: particles as saying like one A two B. That means
Speaker 1: particle one is in state A, in particle two is
Speaker 1: in state B.
Speaker 2: Right, you could also have one B and two A, right,
Speaker 2: and I.
Speaker 1: Understanding absolutely exactly, And so let's do that. Let's take
Speaker 1: our particles one A to B and let's swap them.
Speaker 1: These are identical particles, okay, there's nothing different about them.
Speaker 1: Every electron in the universe, for example, is the same.
Speaker 1: And so let's just swap them. So we go from
Speaker 1: one A to B to one B two A. Right now,
Speaker 1: the quantum field theory of fermions, the math of fermions,
Speaker 1: because they have spin one half. When you do this,
Speaker 1: you get a minus sign. So you can't go from
Speaker 1: one A to B just to one B two A.
Speaker 1: You go to minus one B two A. You get
Speaker 1: a negative sign in front of the quantum state. And
Speaker 1: this has to do with what happens when you're swapping
Speaker 1: them and you're making a face that tells me I
Speaker 1: need to pause so you can ask a question.
Speaker 2: Okay, So we said that you can have one A
Speaker 2: to B as one state, and you can have one
Speaker 2: B two A as another state. Yes, but I thought
Speaker 2: that you were saying that, actually, you can't have one
Speaker 2: B two A. It has to be negative one B
Speaker 2: two A.
Speaker 1: You can have one B two ah. Okay, but if
Speaker 1: you start with one A two B and then you
Speaker 1: swap them, you don't end up at one B two A,
Speaker 1: which you end up with is negative one B two A.
Speaker 2: Okay.
Speaker 1: That's like saying, you know, take your driver's license and
Speaker 1: or flip it around right, you don't necessarily get it
Speaker 1: in this exactly the same orientation depending on how you
Speaker 1: spin it.
Speaker 3: Right.
Speaker 1: Some things like a sphere, doesn't matter how you spin it,
Speaker 1: you end up with exactly the same sphere as perfect symmetry.
Speaker 1: Other things have like a handedness or an orientation right,
Speaker 1: like or take your left hand and turn it around.
Speaker 1: It doesn't look exactly like your right hand. Right, maybe
Speaker 1: it looks like a mirror image of your right hand.
Speaker 1: It's like negative of your right hand. So this is
Speaker 1: the part where we're being like a little bit fuzzy
Speaker 1: and sloppy. But fermions, because they spin one half when
Speaker 1: you swap them, you get a negative sign in the
Speaker 1: quantum state.
Speaker 2: Okay, So that only happens with fermions, not with bosons.
Speaker 1: Only with fermions, not with bosons. And that's what makes
Speaker 1: this impossible. That's where we have a contradiction, right, because
Speaker 1: say you have these two particles in the same state.
Speaker 1: Say you started with one A two A, right, both
Speaker 1: particles in the same state.
Speaker 2: Can't do that, Okay, Oh no, you can with bosons.
Speaker 1: You can with bosons. Well, let's say we have fermions
Speaker 1: and we try to do that. Let's try to do
Speaker 1: that and see what happens. Okay, so we have one
Speaker 1: A two A where like we put two fermions in
Speaker 1: the same place, in the same state. Okay, Well, now
Speaker 1: let's swap them. Well, what happens. Quantum field theory says
Speaker 1: we get negative one A two A. Okay, right, because
Speaker 1: when we swap fermions we get a negative sign. But
Speaker 1: these are supposed to be indistinguishable particles, so if you
Speaker 1: swap them, you shouldn't get any change because there's no
Speaker 1: real difference. You're swapping one A to two you have
Speaker 1: to get one A two A. But quantum field theory says, no,
Speaker 1: you have to get negative one A two A. So
Speaker 1: we have two different rules. One that says if you
Speaker 1: have particles in the same state and they're indistinguishable, and
Speaker 1: you swap them, nothing happens. And the other rule from
Speaker 1: field theory that says if they're fermions and you swap them,
Speaker 1: you get a negative sign. Boom, that's a contradiction. So
Speaker 1: that tells us you just can't do this. You can't
Speaker 1: have fermions in the same state because then if you
Speaker 1: swap them, you get a contradiction. Quantum field theory says
Speaker 1: you're supposed to get a negative sign. Common sense says
Speaker 1: you can't get a negative sign if you swap things
Speaker 1: that aren't different.
Speaker 2: Okay, So the Pauly exclusion principle is the result of
Speaker 2: what happens with quantum field theory.
Speaker 1: Yes, exactly. And you might think, well, what's this negative sign?
Speaker 1: What is going on there? Remember that this negative sign
Speaker 1: is part of the quantum state. It's not something we observe, right,
Speaker 1: a negative sign and a quantum state is not observable
Speaker 1: because every observable you make is only sensitive to the
Speaker 1: quantum states squared. Remember quantum state. It can also be
Speaker 1: like complex numbers. You can have like a wave function
Speaker 1: has like four plus two I in it, and you
Speaker 1: can't observe those things, but when you square it, the
Speaker 1: imaginary part goes away, so we can't observe this. It's
Speaker 1: like a hidden internal part of the quantum state. We
Speaker 1: can't observe. And yet the math is there and it's real,
Speaker 1: and it tells us that fermions cannot do this thing
Speaker 1: because it leads to an inherent contradiction. Now, spin one particles,
Speaker 1: bosons are different. Their rules when you swap them are different.
Speaker 1: If you swap one A two B, and now you're
Speaker 1: talking about bosons, you don't get the negative sign. You
Speaker 1: just get one B two A. Everybody's happy. So if
Speaker 1: you started with one A two A and you swap them,
Speaker 1: quantum field theory says you get one A two A.
Speaker 1: Common sense says you get one A two A, no contradiction.
Speaker 1: Everybody's cool. It's that negative sign, that unobservable negative sign
Speaker 1: in the quantum state that appears for fermions when you
Speaker 1: swap them. That causes them to never be allowed to
Speaker 1: be in the same quantum state if they're indistinguishable fermions.
Speaker 2: Okay, so just to make sure that I'm under so
Speaker 2: like negative one and one, they cancel each other out
Speaker 2: when you add them together.
Speaker 3: Or when you square them you get the same answer.
Speaker 2: Okay, And so I should be keeping that in my head.
Speaker 2: This isn't like we arbitrarily identified that some state is
Speaker 2: negative one, and you could have called the states A, B,
Speaker 2: and C. Like there is actually something about negative one
Speaker 2: and one that is different in an important mathematical.
Speaker 1: Way, exactly. And the important thing here is fermions have
Speaker 1: a different kind of spin, and that changes what happens
Speaker 1: when you swamp them and introduces this negative sign.
Speaker 3: Okay.
Speaker 1: And if you're curious about why that is exactly, this
Speaker 1: is the bit that's famously impossible to explain with intuition.
Speaker 3: We have math for it.
Speaker 1: It's called the spin statistics theorem. And even Richard Meineman
Speaker 1: couldn't come up with an intuitive explanation for it. So
Speaker 1: I hope you're gonna excuse me for not having one either.
Speaker 1: But if you take us out a word for that,
Speaker 1: the fermions, when you swap them, you get a negative
Speaker 1: sign that's not observable, but it does prevent them from
Speaker 1: ever being in the same quantum state. Then you can
Speaker 1: go from there to understand why the Fermi exclusion principle happens.
Speaker 1: And it's going to lead us to think about the
Speaker 1: third way that paraparticles might behave And if.
Speaker 2: You are excited about that, then stick with us, because
Speaker 2: we're gonna get to it after the break. Okay, so
Speaker 2: we teased you before the commercial break that we're going
Speaker 2: to explain to you how para particles behave. Your weight
Speaker 2: is over, Daniel tell us about paraparticles and how they behave.
Speaker 1: So for a long time, decades and decades, people thought
Speaker 1: that fermions and bosons were the only options, not only
Speaker 1: because hey, look, spin one half and integer spins seemed
Speaker 1: like the only choices because like spin one third or
Speaker 1: spin two thirds is impossible, but also in terms of
Speaker 1: the explanation we just gave, it feels like there are
Speaker 1: two options. Either you add a negative sign when you
Speaker 1: swap them, like fermions, which means you can't be in
Speaker 1: the same quantum state, or you don't like bosons, which
Speaker 1: means you can be in the same quantum state. So
Speaker 1: it seems like there's no crack there. It seems like
Speaker 1: there's no room for another direction. And in the nineteen
Speaker 1: seventies somebody went to a bunch of math to prove
Speaker 1: that there is no third option under certain conditions. So
Speaker 1: like if you live in a universe where space has
Speaker 1: three dimensions, then there is no other option. You have
Speaker 1: fermions and you have bosons, and that's its zip and period.
Speaker 1: So people sort of put this away for a long time.
Speaker 1: They were like, yeah, well that's done. Somebody proved it
Speaker 1: dot dot dot. Nobody should ever spend time thinking about
Speaker 1: it again. And that's like a famous place to make
Speaker 1: a big discovery, because I'm sure this happens in biology. Also,
Speaker 1: you have a paper which makes a big advance and
Speaker 1: then it gets sort of summarized in a shorthanded sort
Speaker 1: of way that ignores some of the assumptions that went
Speaker 1: into it, and the conclusions just sort of get broaden
Speaker 1: a little bit, and then people treat the lore as
Speaker 1: if it was real and complete, and people rarely go
Speaker 1: back and read the original paper to discover ooh, actually
Speaker 1: there are coveyats here. So there are loopholes, and people
Speaker 1: who do and discover those loopholes and then explore them
Speaker 1: can like crack open a whole new area of physics.
Speaker 3: Sometimes.
Speaker 2: That's why it is so critical to read and to
Speaker 2: read the original papers.
Speaker 1: And for those of you wondering what that sound is
Speaker 1: in the background. That's a big rainstorm in Virginia right now.
Speaker 2: I love rain. Was that a dig on Virginia?
Speaker 3: Why do you assume that's a dig? That's definitely not
Speaker 3: a dig.
Speaker 2: This is because I know you.
Speaker 1: This week I'm an Aspen for the Aspen Center for Physics,
Speaker 1: and it rains every afternoon and I love it. The
Speaker 1: smell of it in the mountains is just wonderful. The
Speaker 1: thing I do love about mountain rain is that it
Speaker 1: ends also quickly.
Speaker 2: Yeah, well, well those are rainstorms don't last very long.
Speaker 2: And I am the reason you can hear it is
Speaker 2: because I converted the tech room in the barn, the
Speaker 2: horse barn that we have on our property to my office,
Speaker 2: and so there's a metal roof above me, and so
Speaker 2: the metal roof really makes the sound of rain much louder,
Speaker 2: which I love when I'm sleeping up here at night.
Speaker 2: Every once in a while I have sleepovers up here
Speaker 2: with my daughter on Friday nights. But anyway, sorry about
Speaker 2: the background noise, everyone, no problem.
Speaker 1: And we now have enough background to understand paraparticles because
Speaker 1: very recently two physicists at Rice University, which we both
Speaker 1: know and love found some loopholes in this nineteen seventies
Speaker 1: no go theorem, the one the famously said it's impossible
Speaker 1: to have anything but a fermion and a boson. And
Speaker 1: the loophole is, what if you give these particles some
Speaker 1: other kind of properties, things that like a minus sign,
Speaker 1: are not observable directly and disappear when you square it right.
Speaker 1: So like a minus sign is a great example, because
Speaker 1: you square it, you have plus one. If you didn't
Speaker 1: have a minus sign, you can't tell plus one squared
Speaker 1: and minus one squared have the same answer. But they
Speaker 1: came up with another thing you can add to this particle,
Speaker 1: like another category, another part of the description, not a
Speaker 1: minus sign, but like a new dimension to this quantum field,
Speaker 1: a new attribute, a new label you can give it,
Speaker 1: and this kind of thing. Also when you square it,
Speaker 1: it goes away. So there's some technical details here, but
Speaker 1: the sort of way to understand it intuitively is that
Speaker 1: these internal states depend on the observer a little bit.
Speaker 1: So like you and I might see this electron differently
Speaker 1: because we're different observers and we might make different observations.
Speaker 3: So it's a little bit of like relativity there. So
Speaker 3: if you.
Speaker 1: Add this to some particle states in a weird mathematical way,
Speaker 1: you can create a new kind of behavior. So it
Speaker 1: sort of like fuzzes up a little bit, this notion
Speaker 1: of indistinguishable particles. Are the particles indistinguishable or not? So
Speaker 1: you might be wondering, well, we have electrons and we
Speaker 1: have photons. Are there things out there in the universe
Speaker 1: that follow this new weird quantum math. The answer is,
Speaker 1: we don't know, not yet. What they've done is show
Speaker 1: that there is another mathematical description of fields and particles
Speaker 1: that you can construct that has like a third kind
Speaker 1: of behavior. It's not a fermion and it's not a boson,
Speaker 1: but it is self consistent and mathematical. Nobody's built one,
Speaker 1: but they just sort of like mathematically shown that as
Speaker 1: far as we know, the rules of the universe don't
Speaker 1: disallow this.
Speaker 2: So I don't want to ever question the amazing research
Speaker 2: that comes out of Rice University. But it sounds like okay,
Speaker 2: So they're like, well, there's this one thing we can't
Speaker 2: see and can't measure, and so let's add another thing
Speaker 2: we can't see or we can't measure. It's just like fire,
Speaker 2: you know, like biologists can't be like, well, what if
Speaker 2: the viruses we're wearing hats, maybe we should look for
Speaker 2: what's a good combination of hat and viruses?
Speaker 3: Right.
Speaker 1: This is like taking the quantum particles and saying, hey,
Speaker 1: we've only been thinking about them wearing cowboy hats.
Speaker 3: What if they wear other kinds of hats?
Speaker 1: What if choice of hats is another like degree of
Speaker 1: freedom for describing these particles. And it turns out if
Speaker 1: you do that, it cracks this open a little bit
Speaker 1: and it lets you have another category. And so that's
Speaker 1: interesting mathematically. It's only interesting physically if it describes the universe.
Speaker 1: If the universe does this in the same way that
Speaker 1: like DrAk looked at the solutions to the Shortener equation
Speaker 1: and he was like, oh, this is interesting. This allows
Speaker 1: you to have electrons but also allows you to have
Speaker 1: positively charged particles. That doesn't mean the universe does it, right.
Speaker 1: It could have just been like a mathematical oddity like, oh,
Speaker 1: the math allows this, but does the universe choose it?
Speaker 1: And turns out yes, the universe does choose to make antiparticles,
Speaker 1: and the universe in many other cases chooses to explore
Speaker 1: all the avenues of symmetries. We don't know if it does.
Speaker 3: In this case.
Speaker 1: What we've shown is that the mathematics of our description
Speaker 1: of the universe do allow for our third category particles paraparticles,
Speaker 1: but we don't know if they do ever exist in
Speaker 1: the universe, and if they do, we don't think they
Speaker 1: would be fundamental particles the way like photons and electrons are,
Speaker 1: because there are no fundamental particles we know of that
Speaker 1: fall into this category. You'd have to make like quasi
Speaker 1: particles the way you make like anions or plasmons or phonons.
Speaker 1: These are things that follow the math of particles. But
Speaker 1: our waves not in a fundamental field like the electromagnetic
Speaker 1: field or the electron field, but a wave in something else,
Speaker 1: like a wave in air, or a wave in water,
Speaker 1: or a wave in electron gas in some weird meta
Speaker 1: material that solid state physicists cook up in their dark
Speaker 1: little labs. And so it might be something that people
Speaker 1: can create in the labs someday in the future and show, oh, look,
Speaker 1: we've created this new quasi particle that has a different
Speaker 1: kind of mathematical behavior than fermions or bosons. So that
Speaker 1: would be cool and something nobody had seen before. Doesn't
Speaker 1: mean we can make hoverboards or we can make wormholes
Speaker 1: or anything like that yet, But you never know with
Speaker 1: fundamental physics, like what's this going to lead to?
Speaker 3: It's very deep.
Speaker 1: It's very much at the foundation of quantum field theory
Speaker 1: and our understanding of like the mathematics of it. So
Speaker 1: it's exciting when anybody makes any progress in that area.
Speaker 1: And it's a great example to push back on the
Speaker 1: nonsense you might hear online that like physics hasn't made
Speaker 1: any progress since the nineteen seventies. Like, dude, we're making
Speaker 1: progress all the time. And here's a great example.
Speaker 2: So are people currently working on experiments to try to
Speaker 2: find these particles?
Speaker 3: Yeah, more create than find. People are trying to engineer weird.
Speaker 1: Exotic materials that might have these behaviors. And this is
Speaker 1: the kind of stuff solid state physicists love to do,
Speaker 1: you know. They're like, what if we made super thin
Speaker 1: layers of graphene and then super thin layers of this,
Speaker 1: and could we force the electrons to act as if
Speaker 1: they're in a two D universe? Or can we see
Speaker 1: superconductivity or whatever. So they're very clever at engineering materials
Speaker 1: to make quantum states behave in new ways, and that's
Speaker 1: the most promising way. We might see something that's a paraparticle,
Speaker 1: you would be an emergent phenomenon, a quad particle that
Speaker 1: comes out of the behavior of these weird exotic systems
Speaker 1: and not exotic and like impossible or wrong in any way,
Speaker 1: just like not something we find in nature usually. But
Speaker 1: that's the cool thing about being humans. We're like constantly
Speaker 1: pushing the boundaries and saying, hey, can the universe do this?
Speaker 1: What happens if we do that? And it teaches us
Speaker 1: things about the universe. This is how we learn where
Speaker 1: the boundaries are by pushing them, right, yeah.
Speaker 2: Yeah, So when we have a guest on our show,
Speaker 2: you usually end the interview by asking them if an
Speaker 2: alien were to visit our planets from an advanced civilization,
Speaker 2: and you ask them if their thing exists on their
Speaker 2: home planets. That's your way of testing how confident they
Speaker 2: are that the thing actually exists. So, Daniel, if aliens
Speaker 2: from an advanced civilization landed on Earth, do you think
Speaker 2: they would know about paraparticles and would think that paraparticles existed?
Speaker 1: This is a great question and a fair one, since
Speaker 1: I just wrote a whole book on how aliens might
Speaker 1: think about the universe. Y'all should check it out. It's
Speaker 1: coming out in November. It's called Do Aliens Speak Physics.
Speaker 1: I'm really excited about it.
Speaker 2: Two sums way up.
Speaker 1: My personal suspicion is that particle physicists are too up
Speaker 1: in their own heads and they think that the whole
Speaker 1: universe uses their mathematical description of how things work. And
Speaker 1: that's just like too self centered to put ourselves at
Speaker 1: the heart of the understanding of the universe. And likely
Speaker 1: there's a bunch of arbitrary assumptions we've made, and probably
Speaker 1: aliens have a completely different description of how the universe works,
Speaker 1: and they're like, what, why are we even using quantum fields?
Speaker 1: That makes no sense. Here's a much simpler way. But
Speaker 1: if they are using quantum fields, then I think this
Speaker 1: is an inevitable discovery.
Speaker 3: They would make.
Speaker 1: And they might have even found other ways, like there
Speaker 1: might be four, seventeen or ninety two different kinds of
Speaker 1: particles and they're like, what y'all have only found three?
Speaker 1: Come back to us. You can join the cosmic society
Speaker 1: when you're up to ten.
Speaker 2: When you found particles, Then if they talk to us exactly.
Speaker 1: Yeah, and maybe they'll listen this podcast and ooh, particles
Speaker 1: and parasites.
Speaker 3: Maybe these guys are on the right track.
Speaker 2: Oh my gosh. Yeah, at least they'll think that we're interesting.
Speaker 1: Aliens, if you are listening, please don't zap ups from
Speaker 1: outer space.
Speaker 2: Come talk to us, tell us about your secrets, and
Speaker 2: tell us about your parasites, but keep it to yourselves,
Speaker 2: all right.
Speaker 1: Thanks everyone for going on this journey with us into
Speaker 1: the heart of particle physics, how it works, what we know,
Speaker 1: what we don't know, and the hints that mathematics is
Speaker 1: giving us about what we might learn about the fundamental
Speaker 1: nature of space and time and matter and energy and aliens.
Speaker 2: See y'all next time. Daniel and Kelly's Extraordinary Universe is
Speaker 2: produced by iHeartRadio. We would love to hear from you,
Speaker 2: We really would.
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Speaker 1: Extraordinary Universe.
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