What are quantum glasses?

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Speaker 1: Daniel, where are you recording the podcast from these days? Today I'm in my office at the university. Kind of disappointed. Wanted you to be like at the control center of the L C or right next to where the particles collide, kind of like a sportscaster. Nothing so glamorous, but I mean pain a picture for us. What is your office look like? Is it like in a dark dungeon, or is it at the top of the in the Penthouse, at the Corner Office? You know, something in between. I've got a nice window here with a view outside of the southern California landscape, but it's not like the biggest office on the floor. We've got some real big shots around here. You're more of a meeting shot, small shot. I'm a just right shot, your podcast shot now. Is Everything in your office super organized, or are there like huge stacks of papers everywhere? Well, I'm not the kind of person who's at risk for because his desk collapses under a huge tower of papers, but it's not exactly like a well organized museum or anything. It looks lived in. You know, I think lived in his code for missing. I don't know. What do you call something that's like halfway between being neat and missing. Well, I'm a physicist, so I would call it a phase transition. It's like a melting point. You're kind of like a slush, like a slushy. I'm hoping that if they crank of the A C maybe my office will organize itself into a crystal and you'll freeze to death, also for serve for future generations, but at least I'll look neat doing it and you'll be pretty cool too. Hi, I'm poor. Hey, I'm in a cartoonists and the CO author frequently asked questions about the universe. Hi, I'm Daniel. I'm a professor at U C Irvine and a particle is this who worked at the large Hadron collider and I like to think of myself as just messy enough, messy enough for what, before not being neat, messy enough to have that lucky stroke of insight, you know, when that pile of notes you took three years ago at a seminar just sort of falls into your view and provides that crucial piece of information to unlock the puzzle you're working on. If you're too neat and organized and everything's tucked away and you never have that sort of serendipity. I see, and I assume that because your scientists, you have this tested right, you've a scientificity proven, like you've done the control of studies where you're really neat and more missy. Yeah, I have a bunch of other Daniels in the basement and I make them be really neat and messy and I keep track of their careers also, and I guess you're the most successful one because you're not at the basement right, so that proves your theory. I guess I'm the only one with a podcast, which maybe means I'm a failure as a scientist. I'm not sure the other ones are actually doing physics. Is that what you're saying? They're still newon research exactly, but anyways, welcome to our PODCAST, Daniel and Jorge explain the universe, a production of my heart radio, in which we try to find order in this messy universe, this chaotic swirl of particles going to and fro weaving themselves together into this incredible, beautiful reality that we want to make sense of. While galaxies smash into each other and particles annihilate each other, we step back and try to organize all the things that are happening out there in the universe into a crystalline set of ideas that we can transmit along these audio waves into your brains. It's right, because it is a pretty messy universe, full of amazing and exciting things happening out there, particles crashing into each other's black holes sucking up things. And yet somehow we have, as humans, figured out that there is a little bit of a order to all of this, even if we aren't very ordered ourselves. And of course we don't know if that order exists in the universe or if it's just something we have imposed on it. Does the universe actually makes sense? Are we just telling ourselves these stories of UN in the philosophy of physics? But so far it works for us. It lets US build airplanes and transistors and all kinds of new materials that ruin and save our lives. Are you saying the universe is just messy enough? I'm saying it melts my brain sometimes melts in your mouth. All that knowledge, I wonder, what would you like if the universe melted in your hand instead of your mouth? Well, first of all, can you hold the universe in your hand? Only has a thin candy coating, right, but you are in the universe also putting your hand the inside the Eminem two. We are all EMINEM's. That's the philosophy on this show. But are you the chocolate or are you the candy? and which color is your eminem? Knowledge is the chocolate and this show is the candy coating. That helps it go down smooth keeps it from melting in your mouth or in your hand exactly as you crunch on through it, or in your ears. That would be pretty messy. You know what melt the chocolate in your ears. Are you suggesting people do or do not put Eminem's in their ears? That's sort of lost track here. I know children do and we have kids listening. Are you saying you know the results of that experiment, that if you put Eminem's in your ears they do not melt? I can guess what happens, but thing it's science is not about guessing. It's about going out there and doing experiments and discovering what actually happens when you make new arrangements that nobody has ever thought of before. Sometimes it's adding weird metals to other metals, sometimes it's putting eminem's in ears. That's right, because we know the universe is made out of particles and bits of energy out there. But as it turns out, there are lots of different ways you can put together those bits of matter and energy and which gives you all kinds of different results, and there are people still figuring this out. You know, I'm a particle physicists. Of My natural inclination for understanding how the world works is to take it apart, is to reduce it to its smallest, most fundamental elements. But there are other people who work in a completely different direction. Their basic question is, how do we make some new kind of Goo? And can we make good that can do things that Goo never did before? They combine those fundamental pieces of the universe in new ways to try to make him dance and Jiggle and do things that no other kinds of Google have done before. Yeah, because there are many different ways that matter can arrange itself. They're called states of matter. Right, there's liquid and gas and solids and plasma. Right that those are the states of matter that we know of. Those are the famous classical states of matter. But as we explore the universe and push on these things we discover the matter, can do all sorts of weird kinds of things. We talked on the podcast recently about Cork gluon plasma, or you called it Quasma, a great name, by the way. Yes, I'm still waiting for my noble price. Well, just keep eating Banasma as you wait. Yeah, yeah, that might slip with the Noble Price Committee, but it's amazing to me all the things that emerge in our universe. You know, one deep answer to the question what is the universe made out of is to reveal its fundamental bits. But I think it's equally important to understand what those bits do when they work together, because you can't explain the entire universe from the fundamental pieces. Even if you had a complete and unique string theory that described the fundamental theory of everything, you couldn't use it to predict hurricanes or traffic on the four oh five, because these are properties that emerge at a different scale. When you zoom out from the universe from this time, these little bits, you notice these incredible properties, places where we find these interesting and simple mathematical stories that we can tell about the universe, whether or not they are fundamental. Yeah, so there are these four basic states of matter that most people are familiar with, solid gas, liquid plasma, and we're, I guess they're popular and people know them because we see them in our everyday lives. Right. They're sort of what how matter usually sticks together. But, as you were saying, there are many other ways that matter can stick together if you go down into the weirder realm of quantum physics. Yeah, if you stick things together in weird ways and Zap them with lasers, you can find stuff that does things that no other kind of stuff can do. You've probably heard of Bose Einstein condensates, for example, weird collections of particles that act all together as a single quantum state, a macroscopic blob of stuff with quantum properties. That's another example of how you can squeeze and tweak matter into weird configurations to do new kinds of stuff and new kinds of stuff. Is What we'll be talking about here today. So to be on the PODCAST, we'll be asking the question. What are quantum glasses? Now, Daniel, I'm guessing these are not just things you wear to see quantum things better. When we go to a quantum physics conference, everybody puts these things on. It's not going to a three D movie, right. It's for cure and quantum myopia. Is that what it's there for? Or are they for drinking quantum wine or juice? Quantum juice? So you can say I'm not sure if I drink that glass of wine or if somebody else did, shrouding your drink my glass of wine, I meaning glasses of quantum. Have you drunk today? One and zero at the same time. There's a probability distribution that I'm drunk quantum glasses. So these are two words I'm familiar with, but I've never seen them together in the same phrase. These are really interesting kind of materials. Sometimes they're also called spin glasses, as we'll learn about later, because they involve quantum spin. So it's a really fun topic and something a bunch of listeners have been emailing me about because they saw articles about spin glasses and quantum glasses and they wanted to understand. Hey, what are these things anyway? Interesting and can you make a spin bottle out of glass? Is that the same thing? I think you're thinking of the game spin, the boss Spin right. Well, as usually, we were wondering how many people out there had heard of this phrase quantum glasses or had any idea of what they are. So thank you very much to those of you who are willing to answer these questions. It's really helpful to give us a sense for what people are thinking and what they already know. If you'd like to participate for future episodes, please don't be shy. Right to me two questions at Daniel and Jorge Dot Com and I'll set you up. So think about it for a second. What do you think quantum glass this are, and what could you see with them? Here's what to be glad to say. Quantum glasses, I guess, are not spectacles to view through, but they should be a kind of material. In material science, glasses are a class of materials that are characterized by being that it disorganized. So quantum glasses should be a quantum soup that is disorganized. I have no idea. I don't think they're the tiny little reading glasses that some people perched on the end of their nose, nor are they the tiny little shot glasses one might use for a very strong drink. Even those are not quite quantum level, and one should use distance glasses, if any, rather than reading glasses and not drink alcohol while driving a Volkswagen Quantum. So I'm going to take a wild guess that there's something that refocuses beams of quantum particles, much like how eyeglasses and other such lenses refocusames of light. I have absolutely no idea what quantum glasses could be, so this is going to be a completely uneducated guest in every way. My mind originally went to glasses, like glasses who wear, but then I also thought of glasses as like a container for a liquid. So my guess is that it is some type of container through which we can better observe quantum events, events on a quantum scale. I think quantum glasses is a system physicists use two negotiate quantum theory. Either that or it's the glasses I used to use when I was a heavy drinker. But take a guess. Quantum glasses helps you see shrodingerl's cat, exactly what that cat is doing, and it's no whereabouts. If I was to reduce, I reckon it's some way of being able to utilize something to view or to assess the way the quantum world is behaving, similar to a spectacles on to say the world. I wonder if it's got something to do with our ability to say or interact with the quantum world. All Right, a lot of interesting ideas. I love the tiny little reading glasses. They're like little quantum particles you put in your eyeballs. Is that what they're saying? No, I'm imagining like literal tiny glasses perched at the very, very tip of my nose, and they're there and they're not there at the same time. But I'm most impressed with this one guest that says glasses are disorganized. So maybe quantum glasses are a disorganized quantum soup. That is so close to correct I'm amazed. Yeah, yeah, I feel like maybe they cheated or something that. I wonder if they read an article about this. I don't know the rules are. You're not allowed to Google. So, you know, maybe they just intuited it. Maybe this person just is a physics genius. Wow, maybe you should be hiring them, or maybe you already hird them. I don't know. Did you ask your Grad Students? Sometimes? I do sometimes, but these are all random Internet people, although you know, some of our listeners are physics Grad students and some of them aren't. So there's a pretty wide spectrum of backgrounds. Yes, in the end we're all random Internet people, Daniel, but anyways, lots of great ideas, and so let's dig into it. What is a quantum glass? Daniel, break it down for us. So, basically, our listener gave us the answer. A quantum glass is a material where the quantum states are disordered in a way that's similar to way like a window glass is a disordered solid rather than like an ordered crystal. You know. That means that things on the inside are not like arranged, so everything points in the same direction. It's sort of scrambled a little bit. MM interesting because I guess bits of matter, atoms and quantum particles, they have a specific direction, aren't they just like little blobs? They do have specific directions because they have quantum spins, right, and luxurns are not just tiny particles with charred gen mass. They also have other quantum properties, including this weird thing quantum spin, that we don't fundamentally know what it is. We don't think that these electrons are actually spinning because we think of them as point particles. And even if you account for the width of their wave function, if they were literally spinning, then their surfaces would have to go faster than the speed of light to explain all of this energy. It's some other weird property. We have a whole podcast episode about what is quantum spin. For today, all we need to know is that it can have a direction. Electron is gonna be like spin up or spin down, and this is true for other particles. Protons and neutrons and even for atoms, can have an overall spin. So that gives them a directionality. They're not just points, right. They have a property that somehow points in a certain specific direction in space. And you said it's just sort of like normal glass to like maybe let's start with that. What is a normal glass? Yeah, so a normal glass is something that feels solid. Like you go to Your Window Pane Ene and you touch it, it it feels solid, right. But most solids out there are not like glass. Most solids are ordered. They're organized like a crystal, you know. They're sort of like built out of a bunch of tiny bricks that are all stacked together very nicely and neatly into like a big cubic lattice. You can think of them as like a bunch of atoms where the atoms all line up in three directions. You know, if you like sort of looked down it, you could line up all the atoms sort of like in front of you and then along the surface and this kind of thing. So most stuff that's out there is fairly well organized, but a glass is not a glass. It's just sort of like a pile of stuff that's stuck together, but it's not well organized. What do you mean? Mean? Like, my wooden desk is neatly organized, but it looks pretty messy. Your wooden desk is even more complicated because it has all sorts of structure in the wood itself. But you know, if you take it like a block of ice, it's a single kind of stuff. It's cold and the atoms inside of it are arranged in a lattice. There's like the distance between two atoms is pretty much a single number, and that's true for most things like metals, et CETERA. But they're both solid, right, like a piece of glass is solid, just like a piece of ice is solid too. That's right. A piece of glass is solid because its volume doesn't change and it's shape doesn't change. The build just sit there, right. But if you zoomed in with a microscope, an amorphous solid like glass would look very different from a crystal solid, a crystal slid. You would zoom in and it would look like it's built out of these little pieces that are all arranged very nicely, like somebody stacked a bunch of legos together, whereas an amorphous solid would look like, you know, the inside of your Lego bin before you built something would be like a disorganized pile of stuff that's still somehow stuck together. And you know, glass is an example of it. And then we call these things glasses. But there are other examples, like a lot of plastics are like this, gels are like this. You know, sand is like this. If you zoom in close enough, it's not like stacked up in little bricks, it's just sort of like a big jumble. But you're right, it is solid. It manages to stick together well enough still have the properties of a solid, right, although I've heard glasses actually a liquid, like a really slow liquid, right, isn't it? That is something that is said often, but I don't think it's actually true. I think the people have been misled by old windows, for example, that are thicker on the bottom than on the top. That's mostly because of the glass making process at the time. Glass itself, I don't think, actually flows on a time scale that humans can measure, but on a long time scale it sort of does. Right technically, it's true that these things can flow on very, very long time scales, but most of the things where you see it's like thicker on the bottom than on the top is not because the glasses flowed. It's a little bit unclear exactly what the time scale is for glass to flow into a puddle, for example. It might be a very, very long time scale. Well, Um, I guess maybe a question I have is what's the difference between something that is a glass and something that is not a glass? Like what makes some materials arrange themselves into crystal structure, lattices, and what makes them just stick together morphously? The answer is that it is complicated. For some materials it depends on how they are cooled. So if you cool things really, really fast, they don't have a chance for the crystal to organize itself. Other materials just don't fall into a crystal because of the way their interactions work. They can't build a regular lattice it depends a lot on the exact material and also on how you get it to its state. So some things can be crystals or can be glasses, and it just depends on how quickly they are cooled down. Doesn't a lot of it also depend on like the structure of the molecules in the material? For example, you know, like maybe what I think, water falls into crystals because the two H and the o kind of form a kind of a weird shape and there there are only so many different ways you can kind of make those shapes stick together. Yeah, that's what I mean by the interactions of the materials. They imagine. For example, you have a weird shaped tile, a question you can ask is like can I tile this across the floor in a regular pattern? And that's basically what you're trying to do when you build a crystal is like fill up a space with a regular pattern with a weird shape that you have. So, as you say, for example, water has kind of a weird shape, but it's capable of building crystal. But actually it can build lots of different kinds of crystals based on the temperature and pressure of its formation. There's like ice four and ice six and ice. Nine. These are all different crystal arrangements of the same basic thing, based on the temperature and the pressure and the conditions in which it was formed. So it's a really complicated question. Yeah, and I think it also depends on like what makes the molecules stick together right like an h do. It could be the forces between the OHS, for example, what I'm just giving out random example, or it could be, you know, the forces between the H is and things like that, right exactly, and some parts of it are stickier than others, right, depending on the energy levels of their electrons. So it's something that's not always easy to predict. Sometimes the best way to figure it out is just to try. It's just to go out and see what happens. So we have people whose entire careers are just like mapping out the phase diagram of various kinds of materials, understanding what it does under certain configurations. Think maybe the takeaway is that stuff sticks together in general and there are there are many different ways for it to stick together and sometimes they stick together in regular patterns, like in a grid, and sometimes they just kind of bundle up like randomly, right, and that's what a class is and classes is an example of this category. You also have like plastics and polymers and Thoms and gels. These all follow the same kind of structure as glasses. They are amorphous rather than crystalline, right, and those are the in the macro scale there are morphous materials, kind of like the atom level, right. We're not yet at the quantum level. Yeah, these are things at the atom level exactly. So then you're saying a quantum glass is a material in which stuff is stuck together, but Um, it's a morphous in its quantum states. Yeah, and I predict you're gonna be pretty unhappy with this distinction about what's a quantum state or not, because in the end all of these interactions are quantum, like when two water molecules touch each other and form part of a crystal. That is a quantum interaction between quantum particle. But when we talk about quantum glasses, we mean that we're adding a new dimension to it, that we're considering another quantum property, in this case quantum spin, because we're not interested in how the objects ordered themselves in space. We're interested in the distribution of these spins. Are the spins ordered or are the spins disordered. Well, I guess maybe a distinction is that like, for example, for Water and ice? I mean you're talking about atoms being in a kind of a lattice, right, and atoms themselves don't have spin, or you know, don't. Isn't it like the electrons and the atoms and the corks and the atoms that have spin, not the atom itself? The atoms themselves do have an overall spin. It comes from adding up the spin of all the bits, the nuclear spin, the electron spin, and that's what's important for forming magnets, for example, is the spin of the whole atom. It adds up. So we do think about the spin of the atom itself, not just the electrons inside of it. All right, well, let's get more into it and explain what exactly is a quantum glass and whether or not we've actually seen them and can touch them and maybe use them to read quantum books. So let's get into that, but first let's take a quick break. All right, we're talking about quantum glasses. Are these like x Ray glasses that let me see through things? They'll let you see immediately to the next big discovery in physics. I wish isn't I just called working. What if I could just put on quantum glasses and look at my calendar and be like that's the day you're gonna make a big discovery, what would you do? Would you work harder or less if you need you're gonna make a big discovery next week. Well, I know that napping is a crucial part of making big discovery, so make sure to get that out of the way first. Right, right, but would you have more or less if you knew your feature? Well, future Daniel would have already have seen his future using quantum glasses, so that would be accounted for, sort of like Harry Potter time travel. Right, right, I guess that you're saying you don't have any free will. That's right, I'm completely determined by my calendar. I just do whatever it says. That's right. Your naps are determined by your future self. It's not your fault. If I put make huge discovering to the calendar, then I have no choice. I have to make a huge discovery that day. Right. Yeah, that's what I'm saying, but I'm saying like, how would it affect your presence choices? I would type that into my calendar. A lot of times. But anyways, we're talking about quantum glasses and what they are, and we talked about how a glass is a material in which all of the bits in it are kind of disordered, amorphous, not in any kind of grid or structure, and the same can be said for quantum materials. That's right. And traditionally, when we talk about glasses we talk about disorder in the location of the atoms, so if you zoomed in with a microscope you would see like a big pile of stuff rather than a nice, crisp, organized lattice. And now we're talking about something else. We're talking about quantum properties of these objects. So you can have something which is a nice organized lattice in space, like a grid of atoms that are perfectly organized, but it can be a quantum glass if their quantum properties are disorganized, if their spin, for example, so their magnetic moment is not organized in a very nice way. WHOA. So it's almost like something you layer on top of other materials. This idea. It's like, you know, we have this traditional distinction between glasses and crystals, but that is sort of irrelevant here. Right what counts is whether or not the quantum states are aligned in a pattern or not. Exactly whether it's a quantum glass depends on its quantum states, not the spatial locations. And here mostly we're talking about things which are physical crystals. You know, their atoms are nicely arranged in a grid, but the quantum states of those atoms in the grid are sort of scrambled. And you know traditionally if you have stuff in a grid, the magnetic fields can be nicely aligned. So the ferro magnets, for example, is something where all the atoms have their spins in the same direction, which is what controls their little magnetic moments and all adds up to be a big magnet. So if you have a fridge magnet for example, like a nice piece of iron that's been magnetized, has all of its spins in the same direction, they all add up together they make like a permanent magnet. That's a ferro magnet. That's not a quantum glass because the spins are all nicely organized nicely right. That's what a magnet is. Right. Our magnet is usually metal crystal where all of the atoms in it have the same spin direction, which kind of like, I guess, synchronizes them. And makes them add up to a giant kind of spin or magnetic pole. Right. And one reason that's possible is because the spins like to align with each other. In a ferromagnetic material, that's the relaxed state, that's the lowest energy states, when the spins are pointing in the same direction. It likes to be that way. There are other kinds of material, like anti ferromagnets, where they prefer the spins to be the opposite directions, where you want your neighbor to have the opposite spin is you, and because of the way these molecules interact in their funny shapes and all of their forces between them, that happens to be the lowest energy state. That's the opposite anti ferromagnet where you have a crystal, but it's like spin up, down, up, down, up, down, up, down. Both of these are examples of well organized magnetic lattices. Interesting. And does that apply only to metals, like magnet metals? Like can I take a block of ice and align all of the magnetic spins in the atoms of water in a block of ice to make it magnetic? You can't do that with a block of ice. Now, a block of ice is not ferromagnetic and it's also not paramagnetic. paramagnetic ar materials that are sort of weakly magnetic and if you put them in a magnetic field they will eventually align, but then when you take the magnetic field away they might lose it. But ice is neither of those. Why not? Why can't I just, you know, somehow arrange my water molecule so that all the spins are aligned? It depends on how the bits of the atom are organized. So it depends sort of like on the overall spin of the atom. We were talking earlier about having spins on the electrons and spins on the Nuclei. If those sort of all add up to an overall small amount of spin, then there's not really much to play with there. But if they come together in a way that makes like a large magnetic dipole for the individual atom, then you have spins that can get aligned, and so that's what sort of what's different between some materials which are like ferromagnetic because they can be aligned, and other materials that are not. M You're saying like in something like a water atom or molecule, all of the electrons and all the corks in it are not easily or readily aligned. They like to kind of being random positions, which sort of castles. There's spin out. Yeah, and some of these materials, for example, the electrons want to be opposite spins so that they cancel out, and other materials they're set up in a way that electrons can all be in the same spins. You have an overall spin to the atom M and so that's the difference between a material that can form a magnet and one that cannot. That's one of the differences. This whole thing is very complicated. It's difficult to make like broad generalizations, but that's sort of like the cartoon picture. Why some things can be magnetic and some things cannot. All right, so maybe tell me more about these anti ferromagnetic materials. So the anti ferromagnetic materials are the ones where they like to be opposite, where every neighbor prefers to be the opposite of the other, and it just depends on their interactions. Whether that's the lowest energy states, so they like to be up against each other or whether they like to be aligned with each other. They like to be aligned with each other. It's a ferromagnet. They like to be opposite with each other. It's an anti ferromagnet imagine like a big sheet of these atoms. If you want them to be all aligned, there's an easy way to do that. You spin them all up or spin them all down. Right, you want them to be all anti line, there's still a pretty easy way to do that. On a square lattice, like every other one is up and every other one is down. So up, down, up, down, up, down. And you can imagine covering an entire plane or even a three d grid, where every atom's neighbor has the opposite spin as it does right. So if you're up, then you see down everywhere around you in the Lattice, and if you're down, you see up everywhere around to do in the lattice. So there's a way there to make an overall relaxation where everybody's in their lowest state and everybody's happy. I guess I got a little confused because I think basically, like all materials, is kind of a quantum glass, right, like isis sort of a quantum glass because it's quantum spins are in all kinds of directions. Right, like my hand is a quantum glass in that sense of the definition of it, I suppose. So ice and an example, has sort of negligible quantum spins compared to the kind of things we're talking about here. So it's not really in the category of things that we're discussing. We're talking about materials that do have quantum spins. Do they like to be aligned or do they like to be anti aligned? And can you make the material in such a way that the whole thing is happy overall? The whole thing is relaxed into its lowest energy state, either inferro magnets, by lining up all the spins or anti ferro magnets by flipping all of the spins right. But I think you're talking now about like let's post a little challenge for ourselves. Let's let's see if we can find material that you can arrange in a crystal, in the lattice in like a grid, but somehow also make all these spins differently or randomly directed. Yeah, so a spin glass is a kind of material where the spins can't all relax, when you can't find a configuration where everybody's happy. We talked a minute ago about anti ferromagnets, where things like to be the opposite spin of their neighbor. And that works in a square lattice right, where you have like a neighbor to both sides and above you and behind you and in front of you. What if, for example, you have like a triangular lattice instead of a square lattice, and so you have like two neighbors? Imagine just points on a triangle. You Label one point up, the next one down. What's the third point going to be? It wants to be down because has one up neighbor and it wants to be up because it has one down neighbor. So it doesn't know where to go right. It can't satisfy both of its neighbors at the same time. Well, you're saying, I guess that these anti ferromagnetic I guess atoms or molecules. They're sort of like contrarians, like if their neighbor is up, they want to go down right and if they have two neighbors that are up, then they want to go down. I guess two questions. First of all, why are they so continuing? Hey, some people just can be grumpy and you shouldn't ask too many questions. You know, it depends on the complicated interactions between the atoms. Atoms are not simple objects. Have a spatial extent and they're slashing around. They have all their internal forces. You're closer to some bits of it than other bits of it, and the spins of these objects interact right and some of them like to be spin up and some of them like to be spinned down. I guess the short answer is that it's really complicated and sometimes it even depends on distance. Like if you're close up, then they like to have the same spin and as you get further away, they like to have the opposite spin, and then as you gave them further away, they like to be the same spin again. It's really complicated and depends on a lot of the details of that exactly. The internal arrangements of each atom or molecule, I see. But is it, I guess, kind of like a magnet, right, like if I have two magnets and they're both, you know, have the same North Pole pointed in the same direction, like bring them together, like one of them will want to flip over so that it's opposite the other one. Is that kind of like the good analogy, or maybe even the same thing? That's the same thing for the Anti Ferro magnets right, except here we're talking about spins, but it's very similar. You know, the minimum energy state there is for one North Pole to be aligned with the other magnets South Pole, and if you try to push in the other direction, it's going to take some energy to keep it there and if you let go it will relax into the configuration where they have the opposite directions, where the North Pole and one magnet is aligned with the South Pole of other magnets. Okay, so now I think what you're saying is, you know, we have these materials, these atoms, that are contrarian. They like to be opposite the spin of the its neighbors. So now what happens? And if I put two up spins next to it, it's gonna want to be down spin. But what happens if I put an upspin and a down spin next to it? It gets you a little confused, right, or frustrated? Yeah, exactly, and that's what physicists call it. They call it a frustration when you can't arrange the spins in a way so the whole thing has minimum energy right in a square lattice. Imagine four points on a square could have like the top left to be up, on the bottom right be up and the other two points be down and everybody's happy because all the downs have only up neighbors and all the ups have only down neighbors. But in a triangular lattice you can't do that. Right. The third point has one up neighbor and one down neighbor and it can't decide which way to go. There's two possible states there that have the same energy and neither of them are like the minimum energy right. It's like having a conversation between three people and one of them is the contrarian. What happens that? When are the other people agrees with them, but the only one does not? What does the contrarian do? Exactly who to disagree with? And so this is what a spin glass is, because the spins end up sort of like disorganized. It's not like a Pharo magnet where they're all pointing in the same way, or an anti Faro Mac in a square crystal where they're all pointing opposite directions. It's kind of a disaster, right. So like tense, it's frustrated, it can't quite relax, and so where the spins end up is a little bit random. Interesting. So you're saying the part of the definition of what a quantum glass is is that kind of frust rate Shan built it into it. Like if I build the lattice with contrarian atoms and everyone's contrary to their neighbor, then it's and everyone's happy. Then that's not a quantum glass. Right, exactly. That's just a normal anti ferromagnetic crystal. But if you can somehow frustrate the atoms, then you have a quantum glass, because I guess everyone's frustrated and what constantly flipping back and forth? Is that kind of what happens? Yeah, everyone's frustrated, it can't find the minimum and it has new weird properties. So when we talk about a phase transition, there has to be like a change and how the material operates in one of its properties. Right, we don't say that cold water and hot water are different phases, even though they are chemically different, because there's no like large change in its macroscopic behavior. So for years or even decades, there was an argument about whether spin glasses really are their own phase of matter. And the people who say that it is its own phase of matter. They argue that it's unique because it has weird relaxation times. Like if you take a ferromagnet or an anti ferromagnet and you apply really strong magnetic field and you sort of mess up the spins, it will relax pretty quickly when you take away the magnetic field. But a spin glass, if you do that, it will react really differently. It will take like forever to relax and it will never come back to its original position. So people argue that that's enough of a different macro's copic property to be its own kind of thing. What do you mean? It takes a while, like the items keep switching back and forth or what? There's like turmoil inside of the material. Yeah, they have like decision paralysis. You know, it's like if you go to the cookie aisle and there's like a thousand cookies and your shopping list just says cookie. You're like, Oh, do I get Oreos? Do I get chips of oil? Look at those fudge ones. Oh No, I can't decide what I want and they all seem equally good. You could spend hours there wandering around switching, you know, taking stuff in and out of your basket, not sure what to actually buy, and so spin glasses are sort of like this. If you perturb them, you give them magnetic energy, you put them in the magnetic field and then you take it away, they take a long time sort of slashing back and forth spins, flipping and then flipping other spins. They can't find a comfortable situation to relax in M but I guess it isn't spin a quantum property, meaning like each atom has a spin that's both up and down, like they went in a particular direction? Wouldn't that sort of collapse the wave function of that quantum state? Yeah, really interesting question. It's true that spin is a quantum property, which means both that it can either be up or down, but not like in between. Right when you measure these things either get up or down, but it means that until you measure it, it's not necessarily determined. So what that means is that the whole thing has like a few different quantum states that are all possible. We're talking about is what happens when you measure it right. So you probe this thing. You ask like what's the spin over here? What's the spin over here? What's the spin over here? And you're right, that will collapse the wave function so that everybody's going to make a decision, but you come back another minute later and it's made a different decision. You come back another minute later it's made another decision. So you never really see it settle and relax into a fixed state. Right. So when you're talking about like this termoil, all the all the contrarians can not being able to decide which way they're being contrring about. It's more of like a quantum turmol right, like it's not actually flipping back and forth and it's not like you're at the cookie as'le trying to decide. It's like you're sort of in this state where you're you're decided and not decided. No, I think it really is decided or not decided. I mean you can take pictures of these things essentially using like skinning, tunneling, microscopy or otherways to probe the magnetic field. So you can collapse these wave functions and you can see them evolve over time. So you can see these things really are flipping or it's not like once you've collapsed the way function, then it's happy and it's going to stay there. You can collapse the way function, you can come back and collapse it again and then again and again, you can see that they're flipping their spins. So that's the interesting property about spin glasses is that they have these really long relaxation times. They're basically never in equilibrium. You know, another way to think about it is like say you sit down at a really long banquet table and there's silvil ware to your left and to your right. Do you take the one to your left or do you take the one to your right? You know, if everybody takes through to the left, everybody is happy. If everybody takes their right, everybody's happy. People are arguing. You know, no, that one's mine, that one's mine. Then you know you can't really settle into a comfortable state. So spin glasses are situations where, like, people can't agree about what the rules are and so everybody's just taking whatever silverware. Well then, you say, eventually it settles down. And so what is it settled down into? Salad forks or main course for that's the interesting thing about spin glasses is that it's very hard to predict. You know, when we try to understand the macroscopic properties of these things, we do so by starting from the microscopic we say, okay, crystal is made of these little bits, and then we expand our understanding from that basis, stacking them together to make the macroscopic properties. That's really hard to do with spin glasses because they're so crazy and unpredictable. They're basically never in equilibrium. So a lot of the mathematical tricks that we use to understand crystals don't really work for spin glasses, which lad to like invention of whole new categories of mathematics. M interesting. All right. Well, let's get into those new categories of maths and what these materials are good for and what we can learn from them. But first let's take another quick break. All right, we're talking about quantum glasses, which is one of our listeners said, is where you take shots of quantum whiskey or Tequila, one electron at a time. Man, it's quantized. I'll take forever to get drunk. Danny. That's the point, man, moderation in all things. Let See, one atom at a time. Alright. So it sounds like there are materials you can put together in a crystal that are unhappy basically at their core, because all of the atoms can't find a good arrangement of their want them spin the everyone is sort of in this state where they don't know whether to go up or down in their spin, and so you create a material with a lot of frustration in it exactly. And a lot of these spin glasses are not just like one kind of material and a lattice where they're all contrarians and it's arranged in a way where they can't be happy. A lot of the Times it's a few examples of something that is magnetic inside a larger crystal. So you'll have like a non magnetic material like gold or silver copper, and you sprinkle into it a few percent of magnetic atoms, iron or something else, and because of their interactions depend on the distance, whether they like they have the same spin or the opposite spin depends on how far apart they are. You can end up with these disordered spins. You're saying. That's how you make a quantum glass. You embed magnetic atoms into a regular metal exactly, and then you cool it down and you see, like how are they frozen in interesting you like you bake in the frustration of the magnetic atoms. You freeze it in. Yeah, exactly. All right. Well, I guess a good question for me is what are these materials good for or why are we interested in them? So these things don't have like an immediate practical application, if not, like with spin glasses, you can make quantum computers or you can build a better transistor or you can take tiny shots of hot cocoa or something like that. There's no immediate application, but it's an interesting and tricky problem and so people have been thinking about it and, you know, sweating over it and trying to figure out like can we describe these things mathematically? Is there some way to figure this out? To me, this is one of the deep questions of physics itself, you know, because again, since we don't have the fundamental theory of everything, all of the theories that we develop are what we call effective theories. They're like mathematical stories that we tell that describe the things that we see, but they're not like written into the fundamental firmament of the universe. You know, aliens, for example, might not come up with these same effective theories. They're just sort of useful descriptions, but it's incredible we can find them, but sometimes they're harder to find than others. You know, for Solids and for liquids we have found mathematical descriptions that are useful. For Spin glasses, it's been much, much harder because their interactions are more complicated and less regular, but it's inspired people to come up with all sorts of new mathematical tricks, one of which people think is the reason why we discovered the Higgs Boson. I guess maybe a step us through that a little bit more. What does that mean? Like we have an effective theory to describe like a regular magnet. Is that what you're saying? We have like a mathematical way to study the model how regular magnet works, but you're saying we don't have one yet for these crazy, frustrated materials. We've been working on we've been making progress. I mean by we I mean all the other physicists. We're not goofing off making podcasts. We, you know, as the general group of humans thinking about these kinds of things, have been working on this for a long time and I think it's always interesting when it requires a new kind of math. And so there's an Italian physicist Parisi who won the Nobel Prize for this in twenty one, because he came up with a new sort of math, thematical strategy for dealing with this complication. You know, one of the real problems is that these things can arrange themselves in lots of different ways and when you poke them, you know, you give them a little bit more magnetic energy. So you scramble all the spins and you watch them relax. You wonder, like why does it land in this configuration and not that one? Can we predict this kind of thing? Can we come up with some sort of mathematical way to grapple with this and predict what's going to happen? You can't be completely random. And I guess what do you mean by a new kind of math, like a new kind of like adding quantum to old math, or what does that mean? The Way Mathematics bakes progress is that sometimes they need to develop like a new kind of tool, you know, like they find differential equations and here's strategies for solving that kind of problem, or here's Algebra, you know, like the people who figured out how to write equations down and solve them to get understanding. We're able to solve certain problems that other people couldn't. And, for example, descartes made a lot of advances in geometry because he would able to figure out how to use Algebra to tackle geometry. Like if you could write down the equation of a circle, then you could solve systems of equations and understand geometric patterns. So here they've done something similar. They've invented to like new mathematical tools, and these mathematical tools are really thinking about the symmetry of the problem. Like you have this huge, complex tree of options that a spin glass can do. We can splip this way, you can flip that way, you can flip the other way. So what Paris he did was come up with a way to think about this in sort of the larger context, like don't just think about the one spin glass you have, think about all the other spin glasses and you don't have like replicas of that system and try to organize them into like branches. So like, Oh, these guys are all similar in this way, those guys are all similar in these other way. Think about like the choices that were made to get to this spin glass from the higher energy spin glass, and he found these ways to like organize these and use symmetries to like break down the problem into smaller pieces, to organize this complexity, and that helped to make sort of like approximate statements about which kinds of spin glass final states were more likely than others, like if you started here, you're likely to get to neighboring final states where you weren't going to make a big jump to something all the way on the other side of the sort of symmetry organized set of states. And you're talking about math that sort of analyzes one of these grids right like you're looking at a grid of these atoms, these frustrated atoms, together, and you're trying to figure out, like, you know, are they all gonna go up or down, or is they are they going to alternate or are they gonna you know, how often are you going to run into an up spin atom? And you're wondering, if I poke this thing, how likely is it to change to another configuration, or how likely is it, after I've poked it, to come back to this configuration? or how many spins are going to be flipped after I poke it? Is it going to be every single thing is flipped, or just a fraction of you or flipped. So those the kind of questions people are interested in, just like what are the behaviors of these things? So press math gave us sort of like a map for all those different configurations. He said like okay, this configuration of the spin glass, you can put it here on the map, and he was able to sort of organize and create this idea of a distance between one spin configuration and another. This distance is sort of a mathematical way to calculate like how many spins are similar or not, and he was able to organize it in such a way that he showed that if you poke this thing was more likely to end up in a nearby configuration than a distant one, where the distance here is something that he defined his strategy for organizing these different configurations. So there is a pretty interesting kind of material. I guess kind of to go back a little bit to my earlier question is, you know, like let's say I make a piece of quantum glass and it has these interesting mathematical properties. What could I do with it? Can I like make actual glasses out of this glass? What would happen if I see through it? Only if you can see through solid gold or silver or copper. You know, there's not anything that I'm aware that you can like do with it in your life other than impress your physicist friends, which you know, has its own inherent value. I mean it is sort of a quantum object, isn't it? At the end of the day, this glass is a quantum object. Could you do quantum things with it? Or computation for a bit? Possibly? I'm not aware of any applications for quantum computing. But I think with the most interesting thing is just the math that it makes us think about. It made these guys think about symmetries and patterns in new ways and come up with new mathematical tools. And whenever we develop new mathematical tools we always find out that they're useful in other places. So people have been thinking about these kinds of symmetries and crystals for decades and decades in the field we called condensed matter, the study of, you know, dense objects like crystals, and because of that Mathematical Foundation laying in condensed matter there's a lot of work on symmetries, a lot of which informed Peter Higgs when he was thinking about why particles get mass. He came up with this idea of another field in the universe that imparts the mass. But this field has to be really weird and different from any other field he had seen before. It would have to settle and relax into an on minimum energy state. As we've talked about in the program a lot of times. The Higgs field has some weird energy bound into it. It can't relax to its lowest energy state. It relaxed to this weird intermediate state, and so thinking about the symmetry of that problem helped him think about the symmetries and the broken symmetries of the Higgs field and really inspired that Whole Direction of mathematics and particle physics. And that kind of worked out right for Peter Higgs and the press of humanity. But Peter Higgs didn't know about these quantum glass is right. You're just saying that they sort of use the same kind of math and that's why it could be important. That's right. Quantum glasses weren't well understood when he was talking about this kind of stuff and he was thinking about it. But the mathematics that underlie condensed matter and understanding these symmetries led to both a deeper understanding of quantum glasses and of symmetry breaking and the Higgs field. Well, it's interesting that there is a connection, right. I mean there's a connection between the such a fundamental particle in the universe and maybe all particles and what happens at these kind of microscopic levels. Right, maybe the idea that the universe is there's a lot about symmetry in the universe. There is a lot about symmetry in the universe and also about these emergent phenomena. We've talked several times in the podcast about things we call quasi particles. These are weird materials that have states in them that looks sort of like particles that act sort of like particles, you know, like phonons, are waves that pass through a lattice in the crystal and they're sort of similar to photons, but instead of moving through the fundamental electromagnetic field of the universe, they're moving through a crystal lattice. So we see these same kind of properties emerging in condensed matter that we often see also in the quantum fields of the universe, and so there's a lot of connections between the mathematics of solid objects and the mathematics of Space Time itself. Does that inspire you to make your office more symmetric, or do work in at causant state of frustration as well? No, I'm always asking my department here. I'm like, can I get a bunch of gold bricks? I'd like to build a really strict, nice lattice to study their symmetry, but so far having gotten a single delivery of a single gold brick. And you just need to let him your quantum glasses so he can see the future as well. Or maybe he's just gonna Send Me Microscopic Quantum gold bricks, whether either here nor there. Here's one atom of gold. Good luck in this economy. I'd be very happy for even one atom. All right, well, this is an interesting new kind of material and with interesting properties that we're learning more about, and it sounds like it's just another example of the weird things we can find and in this messy universe. You know, like maybe thirty years ago we would never have imagined that we can make a material that is magnetically frustrated. Yeah, and despite all the mess that we find around us, we can still seek order and find patterns and mathematical tricks to analyze it, which turned out to not just help us understand the stuff around us, but also reveal the mathematical patterns that seem to be inherent in the universe itself. Well, we hope you aoid dad. Thanks for joining us. Go have a shot of some quantum drink. have an electron on me. See you next time. Thanks for listening, and remember that Daniel and Jorge explain the universe is a production of I heart radio. 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