WEBVTT - What's a Time Crystal? 0:00:08.680 --> 0:00:11.360 Hey, Katie, did you know that if you stick any 0:00:11.440 --> 0:00:14.480 two science worse together you get a great science fiction 0:00:14.520 --> 0:00:17.480 movie title. Really? Is it really that easy? Oh yeah, 0:00:17.520 --> 0:00:22.439 just give it a shot. Okay, let's see Quantum Hamster Boom. 0:00:22.520 --> 0:00:27.520 I can see that whole movie in my mind alway, Yeah, okay, okay, 0:00:27.520 --> 0:00:31.000 what about Alligator Crystal? I love it? Want to see 0:00:31.040 --> 0:00:36.680 that one. Let's do time, Pump. I'm calling Netflix and 0:00:36.760 --> 0:00:54.800 set up a pitch meeting right now. Hi. I'm Daniel. 0:00:54.880 --> 0:00:57.760 I'm a particle physicist, and I really would like to 0:00:57.760 --> 0:01:01.160 write a science fiction movie someday. And I am Katie. 0:01:01.520 --> 0:01:06.240 I am a science podcaster, and I am already writing 0:01:06.280 --> 0:01:10.160 dialogue for Quantum Hamster in my head. And Welcome to 0:01:10.160 --> 0:01:13.960 the podcast Daniel and Jorge Explain the Universe, a production 0:01:14.200 --> 0:01:16.679 of I Heart Radio in which we take you on 0:01:16.720 --> 0:01:20.240 a tour of everything that's amazing in the universe, everything 0:01:20.240 --> 0:01:23.319 that's out there doing crazy stuff you couldn't imagine, and 0:01:23.400 --> 0:01:26.760 all the weird quantum stuff happening at the particle level 0:01:27.040 --> 0:01:29.800 and everything in between. But we want you to come 0:01:29.840 --> 0:01:32.559 away from our podcast not just hearing about the crazy 0:01:32.600 --> 0:01:36.280 stuff in the universe, but actually understanding it. And as 0:01:36.280 --> 0:01:38.440 you might have guessed, Orge isn't with us today, but 0:01:38.480 --> 0:01:42.800 instead we have a wonderful guest podcast host, Katie introduce 0:01:42.840 --> 0:01:45.840 yourself to everybody. Hi, guys, I am Katie Golden. I'm 0:01:45.880 --> 0:01:49.600 the host of Creature Feature, a podcast about animal and 0:01:49.800 --> 0:01:55.320 human behavior. I studied psychology and evolutionary biology, so I 0:01:55.360 --> 0:01:59.440 am very excited to take a journey into the physics 0:01:59.520 --> 0:02:03.760 realm of things. I hope I can fill Jorges shoes 0:02:03.840 --> 0:02:06.400 a little bit temporarily. Do you know what his shoe sizes. 0:02:07.440 --> 0:02:09.960 He's a cartoonist, so he just draws really big, floppy 0:02:09.960 --> 0:02:14.120 clown shoes and that'll be perfect for me. Well, you 0:02:14.120 --> 0:02:16.480 guys should all check out. Creature Feature is a super 0:02:16.520 --> 0:02:19.160 fun podcast, and Katie's a lot of fun, which is 0:02:19.240 --> 0:02:22.320 why we invite her here as a guest host. And 0:02:22.360 --> 0:02:25.400 you know, today's episode is all about how we understand 0:02:25.440 --> 0:02:28.360 the universe and how we understand things like time, which 0:02:28.360 --> 0:02:30.960 makes me wonder since you're an expert on creatures and 0:02:31.040 --> 0:02:35.840 evolutionary behavior, do animals understand time? Katie? That's a really 0:02:35.880 --> 0:02:39.240 good question. I'd say it depends on the animal, and 0:02:39.280 --> 0:02:43.160 it depends on what you mean by understand a lot 0:02:43.200 --> 0:02:47.320 of animals can kind of mark the passage of time 0:02:47.320 --> 0:02:51.320 without possibly really understanding it. Like there's a great migration 0:02:51.360 --> 0:02:54.920 of plankton that happens every day with the rising and 0:02:55.000 --> 0:02:57.079 setting of the sun. But could you say that as 0:02:57.240 --> 0:03:01.760 little zooplankton really understands time. I'm gonna say no, that's 0:03:01.800 --> 0:03:05.040 a bold, controversial take. But yeah, it's really hard to 0:03:05.080 --> 0:03:07.960 get inside of the heads of animals. That's a problem 0:03:08.240 --> 0:03:11.120 talk about on my podcast. Well, I wouldn't be surprised 0:03:11.160 --> 0:03:14.360 if animals like crows understood time. There's a group of 0:03:14.400 --> 0:03:17.560 crows that seem to always gather outside my window, right 0:03:17.639 --> 0:03:19.640 or like I'm two o'clock in the afternoon when I 0:03:19.639 --> 0:03:23.839 have a big zoom meeting. Yeah, I think patterns are 0:03:23.960 --> 0:03:28.480 really easy for animals to understand, especially the smart ones crows. 0:03:28.520 --> 0:03:30.680 If you feed them, they'll come back and visit you 0:03:30.720 --> 0:03:33.840 whenever you feed them, so they will learn your patterns, 0:03:33.960 --> 0:03:36.040 much like a cat. You know how your cat wakes 0:03:36.080 --> 0:03:38.600 you up just in time early in the morning for 0:03:38.680 --> 0:03:42.600 you to feed them. They understand patterns. They will memorize 0:03:42.680 --> 0:03:48.720 your rhythms and patterns for the best snacking opportunities. Well, 0:03:48.760 --> 0:03:50.320 you know, I was wondering if you were going to 0:03:50.480 --> 0:03:55.000 ask whether any animal understands time, even humans, because as 0:03:55.040 --> 0:03:58.320 you might know, time is a slippery topic and it's 0:03:58.360 --> 0:04:00.680 something a lot of our listeners ask us to talk 0:04:00.680 --> 0:04:03.920 about because it's not something that even human physicists can 0:04:04.000 --> 0:04:07.160 get our minds around. Why do we remember the past 0:04:07.200 --> 0:04:09.680 and not the future? Why is there now? Is the 0:04:09.800 --> 0:04:12.880 now actually real? Or is time just an illusion? All 0:04:12.920 --> 0:04:16.760 of these really simple basic questions about time haven't yet 0:04:16.800 --> 0:04:20.320 been answered. So wait is time? When we're talking about 0:04:20.360 --> 0:04:23.159 time though, is it just a human invention? Like we 0:04:23.279 --> 0:04:26.800 made clocks, we have one o'clock to twelve o'clock, you know, 0:04:26.920 --> 0:04:29.560 we kind of have this concept of time, like is 0:04:29.560 --> 0:04:32.800 it not just our human invention or is there actually 0:04:32.960 --> 0:04:37.760 a real thing of time outside of our little mickey 0:04:37.760 --> 0:04:40.160 mouse watches. Yeah, it's a great question. There's a lot 0:04:40.240 --> 0:04:43.080 of it that is invented by humanity, like units, you know, 0:04:43.200 --> 0:04:46.799 one second, one minute, that's totally arbitrary, and an alien 0:04:46.839 --> 0:04:50.359 species might invent something totally different. But in our understanding 0:04:50.400 --> 0:04:53.360 of physics, time seems to be real, and we will 0:04:53.360 --> 0:04:56.000 dig into that later in the podcast about the concept 0:04:56.040 --> 0:04:58.840 of time in quantum mechanics. And the concept of time 0:04:58.839 --> 0:05:02.240 in general relativity, which turned out to be totally fundamentally 0:05:02.320 --> 0:05:05.520 different ideas of what time is. But yeah, we do 0:05:05.640 --> 0:05:08.159 think the time is a feature of the universe. We 0:05:08.160 --> 0:05:11.000 think it's something out there and real, but we won't 0:05:11.040 --> 0:05:13.479 really know until we one day get to talk to 0:05:13.640 --> 0:05:17.120 alien physicists and see if they even understand the concept 0:05:17.120 --> 0:05:20.680 of time. That's so interesting. So there is an actual 0:05:21.640 --> 0:05:25.880 cosmic time that is occurring that we sort of view 0:05:26.040 --> 0:05:29.200 through our own little human lens, our sun dials and 0:05:29.240 --> 0:05:32.599 our watches and our appointments, but that may not really 0:05:32.640 --> 0:05:35.080 capture the whole truth about what time is. Yeah, or 0:05:35.120 --> 0:05:37.400 it could be an illusion. It could be the time 0:05:37.920 --> 0:05:40.479 is not something deep and fundamental to the universe. It 0:05:40.560 --> 0:05:42.800 could be that it's sort of emerges that it's like 0:05:42.839 --> 0:05:46.680 a special condition that only happens under certain circumstances, you know, 0:05:46.720 --> 0:05:49.760 the way like ice forms sometimes in the universe, but 0:05:49.880 --> 0:05:52.400 not always. You could have a universe without ice. That's 0:05:52.440 --> 0:05:55.640 not a big deal. It might be the time isn't fundamental. 0:05:56.040 --> 0:05:58.479 But we'll dig into all that on today's podcast. We 0:05:58.520 --> 0:06:01.520 actually want to focus today on something even weirder than 0:06:01.640 --> 0:06:04.120 just the question of time, which is a big puzzle 0:06:04.160 --> 0:06:06.480 for physicist. We want to talk about something which has 0:06:06.520 --> 0:06:09.320 been bopping around the Internet and creating a lot of 0:06:09.360 --> 0:06:13.839 buzz recently. That's this topic of time crystals. Oh, that 0:06:13.960 --> 0:06:16.880 sounds beautiful. What comes into your mind when I said it? 0:06:16.960 --> 0:06:20.840 For his time crystals a bunch of clocks floating around 0:06:20.960 --> 0:06:25.919 in a crystalline structure. All right, And so today on 0:06:25.920 --> 0:06:28.840 the program we'll be asking and hopefully answering the question 0:06:33.960 --> 0:06:39.040 what is a time crystal? So, Daniel, you asked people 0:06:39.120 --> 0:06:42.640 on the internet what they thought. That's right. Folks out 0:06:42.680 --> 0:06:46.680 there volunteered to speculate baselessly on the topic of the day, 0:06:46.760 --> 0:06:48.880 just to give us a sense for what they knew 0:06:48.920 --> 0:06:51.479 and what they didn't know. And so if you would 0:06:51.480 --> 0:06:55.480 like to submit your baseless speculations for future podcast episodes, 0:06:55.560 --> 0:06:58.679 please write to me two questions at Daniel and Jorge 0:06:58.960 --> 0:07:02.320 dot com. And so here is what people had to say. 0:07:02.720 --> 0:07:06.320 My only thought is that there are these points in 0:07:06.480 --> 0:07:11.880 space that maybe our time markers, or there are certain 0:07:12.360 --> 0:07:17.520 blocks of crystals that hold elements or signatures of certain 0:07:17.520 --> 0:07:21.480 time events that you can look back on. That's easy. 0:07:22.000 --> 0:07:24.880 Um made a whole Rick and Morty episode about those. 0:07:25.160 --> 0:07:27.640 I don't know what time crystals are. Well, I know 0:07:27.680 --> 0:07:32.280 about Courts is a crystal, and we use courts to 0:07:32.400 --> 0:07:37.920 get precision timing and watches and things like that. Maybe 0:07:37.920 --> 0:07:40.200 there's other crystals that can do the same thing. So 0:07:40.240 --> 0:07:42.400 what do you think about those answers, Katie? I do 0:07:42.520 --> 0:07:45.960 like the call back to Rick and Morty. They definitely 0:07:46.000 --> 0:07:49.080 have a scientific approach to time with all of their 0:07:49.120 --> 0:07:51.400 time travel episodes, do they? Though? Are you a Rick 0:07:51.440 --> 0:07:54.080 and Morty fan? I like it it's a loaded question 0:07:54.120 --> 0:07:55.960 to ask if you're a Rick and Morty fan, because 0:07:56.000 --> 0:07:59.000 I think that there are some really hardcore fans out 0:07:59.000 --> 0:08:02.840 there who will contends that you have to really understand 0:08:02.960 --> 0:08:05.280 science to understand the show, and I just think it's 0:08:05.280 --> 0:08:07.600 a fun show. Yeah, well, you know, I watch Rick 0:08:07.640 --> 0:08:11.200 and Morty sometimes, but I'm a real stickler for getting 0:08:11.200 --> 0:08:14.400 the science right when you're doing time travel, and that's 0:08:14.480 --> 0:08:17.520 really hard. It's very difficult to have a narrative that 0:08:17.600 --> 0:08:20.120 makes sense if you're also going backwards in time and 0:08:20.200 --> 0:08:23.120 jumping all around, and so that sometimes gets the way 0:08:23.160 --> 0:08:25.920 of me enjoying Rick and Morty. I see, you're real 0:08:26.000 --> 0:08:32.120 stickler for those time travel plot holes that always pop up. Yeah, exactly. 0:08:32.559 --> 0:08:35.920 Speaking of time, the focus of today's episode is this question, 0:08:36.040 --> 0:08:38.920 what is a time crystal? I like some of these answers. 0:08:39.120 --> 0:08:42.599 You know, we do use a crystal in watches sometimes 0:08:42.679 --> 0:08:45.200 to tell time, right, crystals are at the heart of 0:08:45.200 --> 0:08:48.240 a lot of watches on people's risks. How do they 0:08:48.400 --> 0:08:50.679 work to tell time? Do you have just a little 0:08:50.760 --> 0:08:53.720 crystal man in your watch going like it's about two thirty? 0:08:54.640 --> 0:08:56.880 That's exactly how it works. You crack it open, you'll 0:08:56.920 --> 0:09:03.480 spot we're writing a Rick and Morty episode. But that's 0:09:03.520 --> 0:09:05.920 not actually the kind of time crystal that we're talking 0:09:05.920 --> 0:09:08.920 about today. Today's episode is about something totally different. So 0:09:08.960 --> 0:09:11.559 what kind of time crystal are we talking about? If 0:09:11.559 --> 0:09:14.199 it's not a little crystal telling you what time it is. 0:09:14.480 --> 0:09:17.520 The idea of a time crystal basically is an extension 0:09:17.880 --> 0:09:21.000 of the idea of a space crystal. So let's first 0:09:21.000 --> 0:09:23.520 talk about what a space crystal is, remind ourselves about 0:09:23.559 --> 0:09:26.080 like the basic idea there, and then we'll try to 0:09:26.120 --> 0:09:30.120 apply that concept to time crystals. Now, I'm imagining a 0:09:30.200 --> 0:09:33.240 crystal floating through space, but I'm going to guess that's 0:09:33.280 --> 0:09:36.720 probably not what it is. No, exactly that's exactly what 0:09:36.760 --> 0:09:39.640 it is for a space crystal, right, A space crystal 0:09:39.760 --> 0:09:42.520 is what it's just like a regular pattern and a 0:09:42.559 --> 0:09:44.400 crystal like the kind of thing that you see like 0:09:44.440 --> 0:09:46.599 a shiny gem or something else you would call a 0:09:46.640 --> 0:09:49.760 crystal is if you zoom down into it and understood 0:09:49.800 --> 0:09:52.720 it like at the molecular or the atomic level. The 0:09:52.760 --> 0:09:55.960 way it's built is like a bunch of Lincoln logs 0:09:56.080 --> 0:10:00.439 or something. You have regularly spaced atoms all end up 0:10:00.600 --> 0:10:03.200 in like a three dimensional pattern. Right, It's that kind 0:10:03.200 --> 0:10:06.800 of grid like structure. I always think of a sort 0:10:06.840 --> 0:10:09.920 of a wafer kind of treat, maybe just because I'm hungry, 0:10:09.960 --> 0:10:13.400 but it's those layers and layers of interlocking wafer like 0:10:13.960 --> 0:10:17.719 molecular structures. Right, Yeah, exactly. You have wafer and then 0:10:17.760 --> 0:10:20.200 you have caramel, then you have another wafer, then you 0:10:20.200 --> 0:10:23.120 have chocolate. That's exactly the recipe for building your crystal. 0:10:23.240 --> 0:10:27.840 Just making me hungrier, Katie's crystal cookies, I love it. Well. 0:10:27.840 --> 0:10:30.440 Sugar is a crystal. Yes, sugar is a crystal. And 0:10:30.440 --> 0:10:33.559 basically anything that's a crystal that has a regular pattern. 0:10:33.840 --> 0:10:36.000 And that's the core concept that we have to understand 0:10:36.040 --> 0:10:39.600 when we're talking about crystals. Basically, you're building a lattice. 0:10:39.880 --> 0:10:43.959 You're taking a continuous symmetry right like space in itself 0:10:44.080 --> 0:10:46.680 is the same everywhere. It doesn't really matter if you 0:10:46.720 --> 0:10:49.040 take one step forward or a half step forward. The 0:10:49.080 --> 0:10:52.080 same laws of physics reply, everything works the same way. 0:10:52.360 --> 0:10:55.640 If you're gonna like juggle balls here, then you took 0:10:55.679 --> 0:10:58.000 a step sideways, the same rules should apply, the same 0:10:58.080 --> 0:11:01.560 juggling should work. A crystal takes that and sort of 0:11:01.600 --> 0:11:05.560 breaks that symmetry into something discreet. So now the universe 0:11:05.800 --> 0:11:09.000 has a symmetry still, but it's not like smooth. You 0:11:09.040 --> 0:11:12.120 have to take like exactly the right size step in 0:11:12.200 --> 0:11:14.600 order to see the universe the same way. So if 0:11:14.600 --> 0:11:16.960 you're like inside a big crystal is a huge lattice 0:11:17.000 --> 0:11:19.280 and you're sitting on an atom, you have to take 0:11:19.400 --> 0:11:21.640 a step exactly the size of the lattice so that 0:11:21.640 --> 0:11:24.559 you're still sitting on an atom. It's chess rules, except 0:11:24.600 --> 0:11:28.000 you're all ponds. Yeah, exactly, take space and break it 0:11:28.080 --> 0:11:30.679 up into chessboards, and you can only move one square 0:11:30.720 --> 0:11:32.720 or two squares. You can't move one and a half 0:11:32.840 --> 0:11:35.160 or two and a half squares. And so that's the 0:11:35.200 --> 0:11:37.319 idea of a space crystal, and like do you think 0:11:37.320 --> 0:11:39.000 of a crystal is a big shiny thing, But when 0:11:39.040 --> 0:11:41.800 you zoom down into it, the reason that it's shiny, 0:11:41.840 --> 0:11:44.840 the reason it has those properties that reflect LFE that way, 0:11:45.240 --> 0:11:48.600 is because it has this regular structure in space. So 0:11:48.640 --> 0:11:51.280 when we say crystal here, we generally just mean like 0:11:51.320 --> 0:11:55.240 a regular, discrete structure. That's so interesting. I mean, crystal 0:11:55.360 --> 0:12:00.160 structures are really interesting and evolutionary biology because they are 0:12:00.200 --> 0:12:05.320 surprisingly sometimes used in eyeballs, like in the eyes of 0:12:06.000 --> 0:12:10.560 mollusks will have these guanting crystal structures that help them 0:12:10.640 --> 0:12:14.960 reflect light. You don't think of organic material as something 0:12:15.000 --> 0:12:17.400 you can turn into a crystal, but yeah, you can 0:12:17.440 --> 0:12:21.439 take guanting form a guanting crystal form an eyeball. That's fascinating. 0:12:21.600 --> 0:12:24.040 So most eyeballs don't have crystals in them. It's a 0:12:24.080 --> 0:12:27.520 special situation. Yeah, we have lenses in most eyeballs, but 0:12:27.640 --> 0:12:31.520 those guanting crystals that form in certain eyeballs, like in 0:12:31.679 --> 0:12:35.480 the eyes of scalps, will have this characteristic that helps 0:12:35.520 --> 0:12:38.319 them reflect light in such a way that gives them 0:12:38.320 --> 0:12:43.480 really interesting vision. And scallops have eyes, yes they do. 0:12:43.760 --> 0:12:46.800 You wouldn't think so, I'll think about that. Next time 0:12:46.800 --> 0:12:50.720 i'm biting into one, I'm tasting crystalline eyeballs. They're actually 0:12:50.760 --> 0:12:53.280 beautiful blue eyes and they have a whole mess of them, 0:12:53.400 --> 0:12:56.040 like two hundred of them. Oh my gosh, Well that 0:12:56.080 --> 0:12:58.199 makes me feel better. That's why I don't eat scalops 0:12:58.200 --> 0:13:01.360 because I don't like crystalline eyeballs. And instead of using 0:13:01.800 --> 0:13:05.440 lenses like a human or mammal eye or most animals eyes, 0:13:05.480 --> 0:13:09.719 they actually use mirrors inside of their eyes as kind 0:13:09.760 --> 0:13:14.800 of a miniature telescope by using that guanting crystal structure. Wow, amazing. Well, 0:13:14.880 --> 0:13:17.719 the other important thing to understand about these kinds of 0:13:17.760 --> 0:13:20.440 crystals that we're talking about space crystals is that they 0:13:20.480 --> 0:13:23.720 are stable. So like those crystals in the eyes of scallops, 0:13:23.840 --> 0:13:26.120 or that diamond that comes up out of the ground 0:13:26.600 --> 0:13:29.120 is stable as the regularly repeating pattern, but it doesn't 0:13:29.200 --> 0:13:32.080 fall apart. It is in its lowest energy state, and 0:13:32.120 --> 0:13:34.240 so we can hang out basically for a long time. 0:13:34.280 --> 0:13:36.480 It needs to be broken up if you want those 0:13:36.520 --> 0:13:40.360 atoms back. Is that why diamonds are so tough because 0:13:40.400 --> 0:13:44.400 of that crystalline structure. Yeah, because the crystalline structure makes 0:13:44.440 --> 0:13:46.679 them really hard to break. And also that's why they 0:13:46.760 --> 0:13:49.000 last a long time because they're in a stable state. 0:13:49.280 --> 0:13:51.680 Like the atoms, they're very happy to be in that situation. 0:13:51.679 --> 0:13:54.720 They're not going to relax into some other lower ground 0:13:54.760 --> 0:13:57.960 state and then break up into something else energetically. They're 0:13:58.080 --> 0:14:01.120 very comfortable. That's so interesting. It's something like an ice 0:14:01.240 --> 0:14:04.520 cube forms a lot of structure, but it does melt. 0:14:04.640 --> 0:14:09.280 So is that an example of like an unstable crystal structure. Yeah. 0:14:09.320 --> 0:14:12.040 Ice is actually super fascinating because it can form lots 0:14:12.080 --> 0:14:14.520 of different kinds of structures. And we're gonna do a 0:14:14.520 --> 0:14:17.440 whole podcast episode about all the different weird kinds of ice. 0:14:17.520 --> 0:14:20.360 It's like one that's not transparent black ice, and it's 0:14:20.400 --> 0:14:23.480 like nine other kinds of ice. So it can form 0:14:23.560 --> 0:14:26.120 lots of weird crystal structures, but actually is in a 0:14:26.160 --> 0:14:28.040 stable state. The only reason it melts is because you're 0:14:28.080 --> 0:14:31.000 adding energy to it. Right. Melting means you're like heating 0:14:31.000 --> 0:14:33.680 it up from the outside. Same with diamonds. You put 0:14:33.720 --> 0:14:37.360 diamonds in hot enough temperatures, they will melt. That actually happens. 0:14:37.360 --> 0:14:39.720 We think sort of like on the surface of Jupiter, 0:14:40.000 --> 0:14:43.440 which rains diamonds into the interior, which might form like 0:14:43.480 --> 0:14:46.920 a big liquid diamond ocean. So Jupiter is really rich, 0:14:47.880 --> 0:14:52.520 talking about Kardashian levels of rich. Absolutely, absolutely, So now 0:14:52.560 --> 0:14:55.240 we understand, like the idea of a crystal, it's like 0:14:55.280 --> 0:14:58.320 a regular structure, but that's a crystal structure in space. 0:14:58.600 --> 0:15:00.320 So now it's turned to the topic we're trying to 0:15:00.360 --> 0:15:03.000 talk about today, which is time crystals. Right, take that 0:15:03.080 --> 0:15:05.960 same idea and apply it to time. Okay, but how 0:15:06.000 --> 0:15:09.640 do you put time in a crystal? Because time is 0:15:09.640 --> 0:15:12.800 not physical matter. You can't arrange it in a lott 0:15:12.800 --> 0:15:15.040 of structure. So what are you trying to say here? 0:15:15.280 --> 0:15:18.440 So take the same idea you're applying to a lattice 0:15:18.480 --> 0:15:21.120 in space, where you say, all right, the thing looks 0:15:21.120 --> 0:15:23.080 the same if I take one step to the right, 0:15:23.200 --> 0:15:25.680 or one step forward or one step backwards. And now 0:15:25.760 --> 0:15:28.800 say what happens if I take a step forwards in time? 0:15:29.360 --> 0:15:32.359 So a time crystals some kind of object or substance 0:15:32.680 --> 0:15:36.760 which has a regular repeating pattern in time, which means 0:15:36.760 --> 0:15:39.360 like it looks the same now and then in a second, 0:15:39.520 --> 0:15:41.720 and then in two seconds, and then in three seconds 0:15:41.760 --> 0:15:43.840 and in between. It doesn't have to look the same, 0:15:44.120 --> 0:15:48.000 but it's going through some transformation so regularly returns to 0:15:48.040 --> 0:15:52.280 the same position. So this is like four dimensional chess 0:15:52.560 --> 0:15:55.520 where it's like you're playing this chess game where you're 0:15:55.520 --> 0:15:58.080 only allowed to move one space at a time in 0:15:58.120 --> 0:16:02.360 a certain direction, but it through time and not through 0:16:02.400 --> 0:16:06.240 physical space necessarily, Yes, exactly. And so what you want 0:16:06.320 --> 0:16:09.560 is something which returns to the same configuration, but after 0:16:09.760 --> 0:16:12.640 discrete units of time, right, not like it's in that 0:16:12.680 --> 0:16:14.520 same state all the time. That would just be a 0:16:14.560 --> 0:16:17.160 space crystal. You want a time crystal which is in 0:16:17.160 --> 0:16:20.320 a certain configuration, then moves out of it and comes back, 0:16:20.680 --> 0:16:22.680 and then moves out of it and then comes back. 0:16:23.160 --> 0:16:26.160 So you wanted to sort of break this continuous time 0:16:26.200 --> 0:16:30.200 symmetry where things always look the same into a discrete symmetry, 0:16:30.560 --> 0:16:32.720 so that it looks the same and then it doesn't, 0:16:32.760 --> 0:16:34.760 and then it comes back and it looks the same again. 0:16:35.040 --> 0:16:36.960 That's the property you have in a space crystal, right, 0:16:37.080 --> 0:16:39.680 you have this distance between points in space. Now we 0:16:39.720 --> 0:16:43.560 want distance between configurations in time. Kind of sounds like 0:16:43.600 --> 0:16:47.160 a dance to me. You have to do your dance 0:16:47.240 --> 0:16:50.640 movements through not just space, but through time, and it 0:16:50.680 --> 0:16:54.720 has to synchronize in a specific way. Yes, exactly, And 0:16:54.760 --> 0:16:57.880 the other critical thing is that it has to be stable, 0:16:58.080 --> 0:17:00.600 meaning it has to be in its grounds eight. That 0:17:00.640 --> 0:17:04.200 means that basically it's doing this forever. So you need 0:17:04.280 --> 0:17:07.879 something which is both in motion but also in the 0:17:07.920 --> 0:17:12.840 most relaxed, lowest energy state, and that's a really unusual combination. 0:17:12.880 --> 0:17:16.560 You have to imagine something basically moving forever that sounds 0:17:16.600 --> 0:17:20.000 like a perpetual motion, which I didn't realize is something 0:17:20.040 --> 0:17:23.320 you could do. Well, my mind is blown, so I'm 0:17:23.359 --> 0:17:26.240 going to try to recollect my brain back into pieces. 0:17:26.280 --> 0:17:28.639 But before we do that, let's take a quick break. 0:17:41.560 --> 0:17:45.000 And we're back and Daniel is trying to reassemble the 0:17:45.040 --> 0:17:49.280 pieces of my brain that exploded. Because we were talking 0:17:49.320 --> 0:17:53.600 about how there is something where with a time crystal 0:17:54.200 --> 0:17:59.280 you can remain in emotion forever at a low energy state, 0:17:59.320 --> 0:18:02.879 which sounds like perpetual motion to me, which I thought 0:18:03.000 --> 0:18:06.360 was just science fiction. So how could this possibly happen? Yeah, 0:18:06.440 --> 0:18:08.879 it's a really awesome question. And it's for this reason 0:18:08.920 --> 0:18:11.679 that people thought forever like this is a silly idea. 0:18:11.960 --> 0:18:15.240 Nobody should even talk about it. It's obviously impossible, and 0:18:15.280 --> 0:18:18.720 it's only recently that people thought maybe there's a way 0:18:18.760 --> 0:18:21.400 to make this happen. Maybe there's a way to configure 0:18:21.440 --> 0:18:25.160 a system that can be in motion through time where 0:18:25.280 --> 0:18:28.119 regularly returns to a specific state that's one of the 0:18:28.200 --> 0:18:31.199 lattest point and yet is stable. So we could like 0:18:31.520 --> 0:18:35.520 do this forever. And this started in about twenty twelve 0:18:35.920 --> 0:18:39.280 when a famous physicist named Frank Wilcheck. He's at m 0:18:39.320 --> 0:18:41.520 I T and he won the Nobel Prize for understanding 0:18:41.600 --> 0:18:44.439 the strong interaction, which is a thing that like binds 0:18:44.520 --> 0:18:47.679 quirks together into protons and neutrons. So he's generally a 0:18:47.760 --> 0:18:50.800 smart guy, and he's also kind of famous for coming 0:18:50.800 --> 0:18:53.359 out of left field with a crazy idea that turns 0:18:53.359 --> 0:18:55.679 out to be pretty good. He's the guy, for example, 0:18:55.680 --> 0:18:59.000 who coined the term axons to describe that hypothetical particle, 0:18:59.160 --> 0:19:02.359 and in he put out this kind of crazy paper saying, 0:19:02.640 --> 0:19:05.720 you know what, here's a situation where time crystals might 0:19:05.760 --> 0:19:10.200 be possible. He constructed an example of a quantum system, 0:19:10.680 --> 0:19:14.160 a ring of particles that sort of rotates and every 0:19:14.200 --> 0:19:17.840 sort of clock cycle returns to a similar configuration and 0:19:17.880 --> 0:19:22.080 repeats the same pattern in time. So exploded into like 0:19:22.160 --> 0:19:25.720 the community of theoretical physics blowing everybody's mind. So is 0:19:25.800 --> 0:19:29.320 this something that would happen on the quantum level. Are 0:19:29.400 --> 0:19:33.800 we talking about entire like star systems doing this like 0:19:34.280 --> 0:19:36.600 time crystal thing, or are we talking about something on 0:19:36.600 --> 0:19:39.919 a very small scale. This is something a very small scale. 0:19:39.920 --> 0:19:42.399 This would definitely be a quantum effect. It's not the 0:19:42.480 --> 0:19:45.320 kind of thing that you can have happened from macroscopic systems. 0:19:45.640 --> 0:19:48.439 And the reason you can only do it potentially for 0:19:48.600 --> 0:19:51.679 quantum systems is that quantum systems have a really weird 0:19:51.800 --> 0:19:55.800 relationship with zero energy. Right. Things that the quantum scale 0:19:55.840 --> 0:19:59.200 can never have exactly zero energy, so when you force 0:19:59.280 --> 0:20:02.600 them into their howest energy state, it's not actually down 0:20:02.640 --> 0:20:05.919 to zero energy. But a whole fun podcast episode recently 0:20:05.920 --> 0:20:09.560 about zero point energy in the Casimir effect, which basically 0:20:09.600 --> 0:20:12.760 says if you look into empty space, it's actually filled 0:20:12.840 --> 0:20:16.440 with an infinite number of photons because all the fields 0:20:16.440 --> 0:20:19.240 that are out there in space can never really relax 0:20:19.400 --> 0:20:22.800 down to zero energy. So time crystals, if you think 0:20:22.840 --> 0:20:27.080 they're possible, could only be possible for tiny, little microscopic 0:20:27.119 --> 0:20:29.960 quantum particles. This is like when my car battery drained 0:20:30.000 --> 0:20:32.879 down to quote unquote zero and the mechanics that I 0:20:33.000 --> 0:20:35.440 need a new one, But hey, guess what, I got 0:20:35.440 --> 0:20:38.720 a little bit more out of that battery. So maybe 0:20:38.720 --> 0:20:42.679 it was some quantum time crystals at work there. Or 0:20:42.680 --> 0:20:45.119 when your iPhone battery says it's at zero but it's 0:20:45.160 --> 0:20:48.080 still running, and you're like, am I using the Casimir 0:20:48.080 --> 0:20:51.320 effect to charge my bode? And you might also be imagining, 0:20:51.600 --> 0:20:54.919 you know, obvious examples of like larger physical systems, not 0:20:55.040 --> 0:20:57.600 just stars, that seem to have this property that they 0:20:57.600 --> 0:21:00.359 could spin, for example, and return to the same state. 0:21:00.440 --> 0:21:03.040 Like think about a wheel with spokes. As it rotates, 0:21:03.040 --> 0:21:06.240 it returns to basically the same configuration. The problem is 0:21:06.280 --> 0:21:10.480 that bicycle wheels, a macroscopic object, could never actually spin forever. 0:21:11.000 --> 0:21:13.320 And that's also not its ground state. It's not the 0:21:13.480 --> 0:21:17.080 most lowest energy state. Lowest energy state for a bicycle 0:21:17.080 --> 0:21:19.840 wheel is when it's stopped right, And so that's why 0:21:19.920 --> 0:21:23.600 we aren't able to actually make a perpetual motion machine 0:21:23.840 --> 0:21:26.760 out of bicycle wheels and water and marbles and so 0:21:26.800 --> 0:21:28.760 on and so forth. But Frank will Check wrote this 0:21:28.800 --> 0:21:30.720 paper and said, you know what, it might be possible 0:21:30.720 --> 0:21:33.840 for quantum objects, basically like a little quantum wheel. He 0:21:34.000 --> 0:21:37.160 tried to show this thing could spin forever and actually 0:21:37.160 --> 0:21:40.000 be in its ground state. Now. Of course this set 0:21:40.040 --> 0:21:43.240 off like a lot of conversations in the theoretical physics community. 0:21:43.520 --> 0:21:46.520 And there's another theorist, Patrick Bruno, who actually found a 0:21:46.600 --> 0:21:51.080 mistake in well checked paper tattletale. I know this, but 0:21:51.160 --> 0:21:54.560 this is a good lesson, like Nobel Prize winners make mistakes. 0:21:54.680 --> 0:21:56.800 I feel like a lot of times people quote Nobel 0:21:56.800 --> 0:21:58.879 Prize winners and if they said it and they want 0:21:58.920 --> 0:22:01.840 a Nobel Prize in must be the truth, right, But 0:22:02.000 --> 0:22:04.560 like they're just people. You know, Yes, they're smart and 0:22:04.600 --> 0:22:07.760 they got lucky, but they're also people and sometimes they 0:22:07.800 --> 0:22:11.919 make mistakes. Ye take that, you Nobel Prize winning smarty pants. 0:22:13.560 --> 0:22:16.240 I especially love it when they interview a Nobel Prize 0:22:16.280 --> 0:22:18.760 winner on a topic they're like, not an expert in 0:22:19.040 --> 0:22:21.600 you know, you'll hear like a Nobel Prize winning physicist 0:22:21.840 --> 0:22:24.560 commenting on economic policy and you're like, you don't know 0:22:24.600 --> 0:22:27.200 anything more about that than anybody else, Like just because 0:22:27.200 --> 0:22:31.480 he won the Nobel Prize, Yeah, you know, I'm as 0:22:31.560 --> 0:22:34.119 much a Nobel Prize winner in a field you didn't 0:22:34.160 --> 0:22:38.160