WEBVTT 1 00:00:01.480 --> 00:00:05.599 Welcome to the quark Side Quantum Physics Podcast, an exploration 2 00:00:05.679 --> 00:00:10.839 of the fundamental structure of reality where quantum laws govern matter, energy, 3 00:00:11.199 --> 00:00:16.239 and information. Here, uncertainty is a feature, not a flaw, 4 00:00:16.719 --> 00:00:19.239 and understanding begins with the smallest scales. 5 00:00:27.600 --> 00:00:32.759 I want you to imagine a completely mind bending scenario 6 00:00:32.840 --> 00:00:33.359 for a second. 7 00:00:33.600 --> 00:00:34.240 I am listening. 8 00:00:34.520 --> 00:00:37.520 So picture a physical material, like maybe a sleek, little 9 00:00:37.520 --> 00:00:39.719 metallic panel, sitting on a desk right in front of 10 00:00:39.719 --> 00:00:44.240 you right now. Imagine a concentrated beam of heat hits 11 00:00:44.280 --> 00:00:49.000 this material from the right side. Naturally, the material absorbs 12 00:00:49.039 --> 00:00:50.200 that thermal energy rip. 13 00:00:50.359 --> 00:00:51.439 That is just basic physics. 14 00:00:51.520 --> 00:00:55.159 Yeah, exactly. It starts getting warm. But here is the 15 00:00:55.200 --> 00:00:59.000 bizarre part. Instead of eventually radiating some of that heat 16 00:00:59.079 --> 00:01:03.399 back out towards the right side, it completely refuses to 17 00:01:03.560 --> 00:01:07.000 emit heat in that direction. Really yeah, it acts like 18 00:01:07.000 --> 00:01:09.599 an impenetrable brick wall to its own heat on that 19 00:01:09.680 --> 00:01:13.519 right side. But then it turns around and radiates all 20 00:01:13.599 --> 00:01:15.959 that absorbed heat straight out to the left side in 21 00:01:16.040 --> 00:01:19.200 order to cool itself down. Wow, I know, right. It 22 00:01:19.239 --> 00:01:22.040 takes heat in from one direction and exclusively shoots it 23 00:01:22.079 --> 00:01:22.719 out in another. 24 00:01:23.000 --> 00:01:24.920 I mean, it sounds like a magic trick, or at 25 00:01:24.959 --> 00:01:28.439 least a fundamental violation of how we intuitively understand the universe. 26 00:01:28.519 --> 00:01:31.959 It really does, because when an object gets hot, we 27 00:01:32.040 --> 00:01:34.680 expect it to glow, so to speak, in all the 28 00:01:34.760 --> 00:01:37.920 ways it was capable of receiving that heat. A campfire 29 00:01:38.000 --> 00:01:40.159 doesn't just radiate heat to the north. 30 00:01:40.239 --> 00:01:42.120 No, it feels like a glitch in the matrix. But 31 00:01:42.159 --> 00:01:44.519 this isn't science fiction. Okay, let's unpack this. 32 00:01:44.719 --> 00:01:45.159 Let's do it. 33 00:01:45.200 --> 00:01:48.799 We are looking at a groundbreaking new concept today, recently 34 00:01:48.799 --> 00:01:52.519 published by researchers at Osaka Metropolitan University in the journal 35 00:01:52.599 --> 00:01:54.959 Laser and Photonics Reviews. 36 00:01:54.359 --> 00:01:55.680 A huge deal in that field. 37 00:01:55.799 --> 00:02:00.159 Oh absolutely. It is a paradigm shift where heat can 38 00:02:00.239 --> 00:02:05.560 actually be directed, steered, and literally programmed, almost exactly like 39 00:02:05.719 --> 00:02:07.359 data routing through a microchip. 40 00:02:07.519 --> 00:02:11.120 The implications here are just absolutely staggering from modern engineering. 41 00:02:11.159 --> 00:02:14.680 I mean, we've spent the entire history of technology treating 42 00:02:14.719 --> 00:02:17.759 heat as a stubborn, chaotic byproduct. 43 00:02:17.879 --> 00:02:19.719 Yeah, just a massive annoyance exactly. 44 00:02:19.759 --> 00:02:22.319 So the ability to direct it on purpose, but literally 45 00:02:22.360 --> 00:02:25.520 tell heat exactly where it is allowed to go, well, 46 00:02:25.680 --> 00:02:27.879 that changes the foundational rules of how we build. 47 00:02:27.680 --> 00:02:30.319 Machines, and that is exactly why we are bringing this 48 00:02:30.360 --> 00:02:33.360 to you today. This isn't just a dry physics lesson. 49 00:02:33.120 --> 00:02:33.599 Not at all. 50 00:02:33.680 --> 00:02:36.800 This is a real tangible glimpse into the future of 51 00:02:36.840 --> 00:02:40.039 how every single device around you, from the smartphone in 52 00:02:40.080 --> 00:02:44.360 your pocket to the massive energy hungry server farms powering 53 00:02:44.400 --> 00:02:47.599 the Internet, might very soon manage energy. 54 00:02:48.039 --> 00:02:51.400 But to appreciate how revolutionary it is to steer heat 55 00:02:51.560 --> 00:02:54.520 like this, we really need to take a step back, right. 56 00:02:54.800 --> 00:02:57.240 We need to look at the invisible wall these researchers 57 00:02:57.280 --> 00:02:59.960 had to break through before we could talk about how 58 00:03:00.159 --> 00:03:03.680 Professor Koitici Yokomoto and doctor Shunsukeamurai managed to build this 59 00:03:03.800 --> 00:03:07.680 directional heat valve. We have to understand the fundamental physics 60 00:03:07.759 --> 00:03:11.199 rule that made this seem well impossible for so long. 61 00:03:11.840 --> 00:03:13.919 You're talking about the concept of reciprocity. 62 00:03:14.039 --> 00:03:16.560 That's the one in the world of thermodynamics and optics. 63 00:03:16.840 --> 00:03:20.319 Reciprocity is a very strict fundamental relationship. 64 00:03:19.800 --> 00:03:21.000 Like an unbreakable rule. 65 00:03:21.199 --> 00:03:24.039 Pretty much, it means that the way a material absorbs 66 00:03:24.080 --> 00:03:27.000 heat and the way it emits heat are perfectly linked. 67 00:03:27.039 --> 00:03:27.960 They are inseparable. 68 00:03:28.039 --> 00:03:29.719 Okay, So how does that work in practice? 69 00:03:29.759 --> 00:03:32.159 Well, let's say you have a specific surface, and it 70 00:03:32.240 --> 00:03:36.599 is exceptionally good at absorbing thermal energy at a specific wavelength, 71 00:03:37.000 --> 00:03:39.159 and it's best absorbing it when the heat arrives from 72 00:03:39.159 --> 00:03:40.120 a specific angle. 73 00:03:40.360 --> 00:03:45.479 Okay, So this hypothetical surface has a preferred flavor and 74 00:03:45.560 --> 00:03:48.560 like a preferred angle for incoming heat. 75 00:03:48.759 --> 00:03:52.759 Exactly, the law of reciprocity dictates that this exact same 76 00:03:52.840 --> 00:03:56.560 surface is physically forced to emit heat in that exact 77 00:03:56.599 --> 00:03:57.080 same way. 78 00:03:57.199 --> 00:03:57.879 Oh, I get it. 79 00:03:58.000 --> 00:04:01.479 If it's a great absorber at that wavelength and direction, 80 00:04:02.199 --> 00:04:05.000 it must be an equally great emitter at that wavelength 81 00:04:05.080 --> 00:04:09.039 and direction. The absorption and emission profiles are locked together 82 00:04:09.120 --> 00:04:11.039 in a perfect mirror image. 83 00:04:10.680 --> 00:04:15.360 Because nature demands this symmetry to maintain equilibrium. 84 00:04:15.400 --> 00:04:16.680 Right, you hit the nail on the head. 85 00:04:16.720 --> 00:04:19.560 It's kind of like a sponge. Think of a highly 86 00:04:19.600 --> 00:04:21.720 porous sponge sitting on your kitchen counter. 87 00:04:21.839 --> 00:04:23.319 Okay, picturing the sponge. 88 00:04:23.399 --> 00:04:25.879 If it is incredibly porous on the top surface, it's 89 00:04:25.879 --> 00:04:28.639 going to easily absorb water that is poured directly onto 90 00:04:28.680 --> 00:04:31.240 it from above, right, Right, But because of that exact 91 00:04:31.319 --> 00:04:34.639 same physical structure, if you push down on that sponge, 92 00:04:34.639 --> 00:04:36.959 it's going to easily squeeze the water right back out 93 00:04:36.959 --> 00:04:40.160 through that same top surface exactly. Yes, the physical channels 94 00:04:40.160 --> 00:04:42.839 that let the water in are the literal pathways out. 95 00:04:42.879 --> 00:04:44.720 The structure is totally symmetrical. 96 00:04:45.000 --> 00:04:49.439 That physical pathway analogy is crucial here. The structural properties 97 00:04:49.480 --> 00:04:51.839 governing the inflow and the outflow are one and the 98 00:04:51.879 --> 00:04:53.839 same at a microscopic level. 99 00:04:53.839 --> 00:04:56.240 But I'm going to play Devil's advocate for a second here. 100 00:04:56.360 --> 00:05:01.319 As an everyday person, symmetry sounds elegant. It's perfectly balanced. 101 00:05:01.759 --> 00:05:06.040 So why is this natural symmetry actually a massive headache 102 00:05:06.439 --> 00:05:09.399 for engineers who are trying to manage thermal energy in 103 00:05:09.480 --> 00:05:10.480 modern technology? 104 00:05:10.720 --> 00:05:14.279 Well, this raises an important question because elegance in theoretical 105 00:05:14.279 --> 00:05:18.439 physics is often an engineer's worst enemy. Ah, fair point, 106 00:05:18.680 --> 00:05:23.600 reciprocity severely limits our ability to independently control heat. I mean, 107 00:05:23.639 --> 00:05:27.720 think about modern electronics. We are packing billions of microscopic 108 00:05:27.720 --> 00:05:30.519 transistors into chips the size of a fingernail. 109 00:05:30.560 --> 00:05:32.720 It's crazy when you really think about it. 110 00:05:32.399 --> 00:05:35.199 It is, and they generate immense amounts heat, and that 111 00:05:35.279 --> 00:05:37.920 heat is the ultimate killer of computing performance. 112 00:05:38.040 --> 00:05:40.040 Oh yeah, we all know the sound of a laptop 113 00:05:40.079 --> 00:05:41.879 fan spinning up like a jet engine. When we open 114 00:05:41.959 --> 00:05:43.000 too many browser tabs. 115 00:05:43.040 --> 00:05:46.519 Exactly. So, imagine you are an engineer trying to design 116 00:05:46.519 --> 00:05:49.959 a passive system to pull that dangerous heat away from 117 00:05:49.959 --> 00:05:54.279 a highly sensitive processor. Because of reciprocity, heat is always 118 00:05:54.319 --> 00:05:57.000 a two way street. If you design a material that 119 00:05:57.120 --> 00:06:00.680 is highly efficient at pulling heat away from that processor, 120 00:06:01.160 --> 00:06:04.600 that same material acts as a perfect bridge to radiate 121 00:06:04.680 --> 00:06:08.560 heat right back into the processor. If the environmental conditions 122 00:06:08.600 --> 00:06:09.720 shift even slightly. 123 00:06:09.839 --> 00:06:11.600 Oh wow, I see, you can just build an exit 124 00:06:11.600 --> 00:06:13.720 door because if it functions as a door, the heat 125 00:06:13.759 --> 00:06:16.120 can use it to walk right back inside the building. 126 00:06:16.240 --> 00:06:19.879 Exactly. You cannot design a device that safely and permanently 127 00:06:19.879 --> 00:06:23.040 pulls heat away without the constant risk of it acting 128 00:06:23.079 --> 00:06:24.079 as a two way conduit. 129 00:06:24.199 --> 00:06:25.439 That is super frustrating. 130 00:06:25.480 --> 00:06:28.439 You are constantly fighting against the materials innate desire to 131 00:06:28.480 --> 00:06:32.079 reach equilibrium in both directions. This is why advanced thermal 132 00:06:32.120 --> 00:06:34.839 management today is incredibly inefficient and bulky. 133 00:06:35.000 --> 00:06:36.519 Right the giant fans yep. 134 00:06:36.959 --> 00:06:41.800 We rely on elaborate active cooling systems, loud fans, massive 135 00:06:41.839 --> 00:06:45.639 copper heat sinks, and liquid cooling loops just to forcibly 136 00:06:45.680 --> 00:06:47.560 blow the heat away before it can travel back down 137 00:06:47.600 --> 00:06:47.959 the bridge. 138 00:06:48.000 --> 00:06:51.560 Okay, so, knowing that reciprocity is this unavoidable universal two 139 00:06:51.560 --> 00:06:54.480 way street really makes what the team out of Soccer 140 00:06:54.519 --> 00:06:57.319 Metropolitan University accomplished seem totally absurd. 141 00:06:57.399 --> 00:06:58.040 It really does. 142 00:06:58.199 --> 00:07:01.600 They somehow engineered a loop. They figured out a way 143 00:07:01.600 --> 00:07:05.519 to break the sponge. They completely separated the absorption of 144 00:07:05.560 --> 00:07:07.519 heat from the emission of heat, and. 145 00:07:07.480 --> 00:07:10.639 They did it by looking beyond standard natural materials. They 146 00:07:10.680 --> 00:07:14.279 had to create an entirely new composite structure to break 147 00:07:14.319 --> 00:07:15.319 that fundamental symmetry. 148 00:07:15.399 --> 00:07:19.800 Here's where it gets really interesting. They engineered a Frankenstein material. 149 00:07:20.000 --> 00:07:20.399 They did. 150 00:07:20.560 --> 00:07:24.519 They combined two completely different, highly specialized types of materials 151 00:07:24.560 --> 00:07:28.720 into a single device to force this one way street 152 00:07:28.759 --> 00:07:33.199 into existence. And the formal scientific term for what they 153 00:07:33.279 --> 00:07:37.519 build is a phase change magneto optical metigrading. 154 00:07:37.800 --> 00:07:40.480 It's quite a mouthful, I know, but breaking it down 155 00:07:40.519 --> 00:07:44.399 into its core components reveals a really brilliant mechanical logic. 156 00:07:44.480 --> 00:07:46.120 I'm going to stop you right there, though, because the 157 00:07:46.160 --> 00:07:49.360 first part of that, the magneto optical material, immediately breaks 158 00:07:49.360 --> 00:07:49.759 my brain. 159 00:07:49.839 --> 00:07:51.360 Oh really, how so. 160 00:07:51.480 --> 00:07:54.000 You're saying we are steering heat with magnets? I mean, 161 00:07:54.040 --> 00:07:57.120 I thought magnets only affected metals like iron. Heat is 162 00:07:57.199 --> 00:07:59.920 just thermal energy. How on Earth does a magnetic few 163 00:08:00.040 --> 00:08:01.160 old sphear temperature. 164 00:08:01.439 --> 00:08:04.480 That is the perfect question, and it requires a quick 165 00:08:04.560 --> 00:08:07.759 shift in how we think about heat. When we talk 166 00:08:07.800 --> 00:08:11.199 about thermal radiation in this context, we aren't talking about 167 00:08:11.240 --> 00:08:14.680 hot air blowing around, Okay, we are talking about infrared light. 168 00:08:15.680 --> 00:08:21.040 Thermal energy is fundamentally electromagnetic radiation. It's just light that 169 00:08:21.079 --> 00:08:22.199 our eyes can't see. 170 00:08:22.279 --> 00:08:24.639 Oh okay, so heat is light. That makes it way 171 00:08:24.639 --> 00:08:25.839 easier to visualize. 172 00:08:25.959 --> 00:08:29.240 Right, And once you accept that heat is an electromagnetic wave, 173 00:08:30.000 --> 00:08:32.480 the magneto optical material actually makes. 174 00:08:32.360 --> 00:08:35.039 Sense because it interacts with light exactly. 175 00:08:35.440 --> 00:08:38.399 The defining property of these materials is that their interaction 176 00:08:38.480 --> 00:08:42.320 with light can be physically altered by applying a magnetic field. 177 00:08:42.600 --> 00:08:44.960 How does the magnet actually alter the light though? 178 00:08:45.320 --> 00:08:48.639 Well, the magnetic field breaks what physicists call time reversal 179 00:08:48.720 --> 00:08:51.200 symmetry for the light waves traveling through the material. 180 00:08:51.279 --> 00:08:53.840 Time reversal symmetry. Wait, are we talking about time travel now? 181 00:08:54.039 --> 00:08:54.320 Huh? 182 00:08:54.360 --> 00:08:56.240 Not quite? Yeah. Think of it like a video of 183 00:08:56.240 --> 00:08:58.759 a billiard ball bouncing off the cushion of a perfectly 184 00:08:58.840 --> 00:08:59.720 level pool. Table. 185 00:09:00.000 --> 00:09:00.919 Okay, got the visual. 186 00:09:01.120 --> 00:09:04.360 If you play that video in reverse, the ball's trajectory 187 00:09:04.360 --> 00:09:07.000 looks perfectly natural. You wouldn't even know the video is 188 00:09:07.000 --> 00:09:11.399 playing backwards. That is time reversal symmetry. The path works 189 00:09:11.440 --> 00:09:12.840 identically in both directions. 190 00:09:12.960 --> 00:09:13.799 Nice total sense. 191 00:09:14.000 --> 00:09:17.159 Now, imagine a slanted pool table. If you play a 192 00:09:17.240 --> 00:09:20.799 video in reverse of the ball rolling down that slant, 193 00:09:21.240 --> 00:09:25.480 you'd suddenly see a ball defying gravity rolling uphill. It 194 00:09:25.559 --> 00:09:26.600 immediately looks. 195 00:09:26.360 --> 00:09:29.799 Wrong, right, because gravity doesn't work that way exactly. 196 00:09:30.320 --> 00:09:33.399 The magnetic field applied to this material creates a sort 197 00:09:33.440 --> 00:09:37.279 of one way slope for the electromagnetic waves. It literally 198 00:09:37.320 --> 00:09:40.919 tilts the playing field. Wow, the light can travel smoothly 199 00:09:40.919 --> 00:09:44.440 in one direction, but the physics of the material actively 200 00:09:44.480 --> 00:09:46.559 resist the light traveling back the way it came. 201 00:09:46.879 --> 00:09:50.159 That is a phenomenal analogy. The magnet basically tilts the 202 00:09:50.159 --> 00:09:53.320 pool table for the infrared light. But a magnet is 203 00:09:53.399 --> 00:09:55.559 just a force. It doesn't give us a physical switch 204 00:09:55.600 --> 00:09:57.960 we can turn on and off inside the material itself 205 00:09:58.000 --> 00:09:59.960 to lock that pathway into place. 206 00:10:00.039 --> 00:10:01.799 Which brings us to the second component. 207 00:10:01.840 --> 00:10:05.840 They integrated, the phase change material called GST Exactly. 208 00:10:06.480 --> 00:10:10.440 GST stands for germanium and ammoni tlorium. It's a highly 209 00:10:10.480 --> 00:10:14.759 specialized alloy. And what makes GST so critical here is 210 00:10:14.799 --> 00:10:18.039 that it can transition between two very different solid states. 211 00:10:18.120 --> 00:10:19.120 Okay, what are there? 212 00:10:19.600 --> 00:10:23.360 There is an amorphous state where its atoms are arranged chaotically, 213 00:10:23.840 --> 00:10:26.720 and a crystalline state, where its atoms are arranged in 214 00:10:26.720 --> 00:10:28.879 a highly ordered geometric grid. 215 00:10:29.200 --> 00:10:31.360 You know, usually when I hear phase change, I think 216 00:10:31.360 --> 00:10:34.320 of water boiling into steam or freezing into ice. 217 00:10:34.559 --> 00:10:38.200 It's the same underlying concept of a substance altering its 218 00:10:38.200 --> 00:10:41.679 physical properties, but it's happening entirely at a solid state level, 219 00:10:41.720 --> 00:10:44.080 so it never melts. Right, The material never melts into 220 00:10:44.120 --> 00:10:47.679 a liquid. Its internal atomic structure just completely rearranges itself 221 00:10:48.200 --> 00:10:51.399 and critically. Its optical properties, like how it absorbs and 222 00:10:51.399 --> 00:10:55.200 reflects that infrared heat, changed drastically depending on which state 223 00:10:55.279 --> 00:10:55.600 it is in. 224 00:10:55.759 --> 00:10:58.759 Wait, it's actually the same fundamental technology that we used 225 00:10:58.759 --> 00:11:02.159 for decades to store data and rewriteable CDs and DVDs, 226 00:11:02.200 --> 00:11:02.559 isn't it? 227 00:11:02.559 --> 00:11:04.639 It is the exact same family of materials. 228 00:11:04.679 --> 00:11:07.279 Yes, Like a laser burns a tiny spot to change 229 00:11:07.279 --> 00:11:10.320 its state, making it either reflective or non reflective. To 230 00:11:10.360 --> 00:11:12.360 read ones and zeros precisely. 231 00:11:12.919 --> 00:11:15.879 But here they aren't just using it to reflect a laser. 232 00:11:16.200 --> 00:11:19.159 They are using it to physically rebuild the pathways the 233 00:11:19.200 --> 00:11:20.559 heat is trying to travel through. 234 00:11:20.799 --> 00:11:23.159 So if we go back to the idea of a 235 00:11:23.240 --> 00:11:25.759 room with a door, it's not just acting as a 236 00:11:25.759 --> 00:11:30.120 switch that opens or closes. It's literally rearranging the furniture 237 00:11:30.120 --> 00:11:32.120 in the room so the heat can't even find the door. 238 00:11:32.799 --> 00:11:35.559 In the amorphous state, the atoms are like a chaotic 239 00:11:35.639 --> 00:11:38.879 crowd of people blocking the exit. Heat gets trapped. 240 00:11:39.200 --> 00:11:40.200 I love that visual So. 241 00:11:40.240 --> 00:11:43.080 Then you apply a pulse of energy and those atoms 242 00:11:43.279 --> 00:11:47.519 instantly form a disciplined crystalline grid, opening up a perfect 243 00:11:47.600 --> 00:11:49.600 clear hallway for the heat to escape. 244 00:11:49.639 --> 00:11:52.360 That is a very accurate way to visualize it. By 245 00:11:52.399 --> 00:11:55.679 combining these two elements, by patterning the GST material on 246 00:11:55.720 --> 00:11:58.799 top of the magneto optical material, they created what's called 247 00:11:58.840 --> 00:12:00.399 a metigrating impact. 248 00:12:00.440 --> 00:12:02.679 Metigrating for a second, we always throw around words like 249 00:12:02.720 --> 00:12:05.879 microscopic structures, but why does the physical shape actually matter. 250 00:12:06.240 --> 00:12:11.080 Well, ametigrating is a surface engineered with microscopic physical ridges 251 00:12:11.080 --> 00:12:14.159 and patterns. Think of the grooves on a vinyl record. 252 00:12:14.360 --> 00:12:17.720 But scaled down so incredibly small that the size of 253 00:12:17.720 --> 00:12:21.000 the grooves is roughly the exact same size as a 254 00:12:21.039 --> 00:12:22.679 single wavelength of infrared light. 255 00:12:23.200 --> 00:12:25.120 Oh wow, that is tiny. 256 00:12:24.960 --> 00:12:28.039 Very tiny, And because the physical geometry is the same 257 00:12:28.120 --> 00:12:31.919 size as the light waves, it physically forces the light 258 00:12:32.159 --> 00:12:36.480 to bend, trap, or guide itself in highly specific directions 259 00:12:36.840 --> 00:12:38.559 based on how it hits those ridges. 260 00:12:38.639 --> 00:12:41.399 Okay, so we have the magneto optical material tilting the 261 00:12:41.399 --> 00:12:45.200 pool table, the GST physically rearranging the furniture to open 262 00:12:45.360 --> 00:12:48.840 or close pathways, and the metigrating ridges physically guiding the 263 00:12:48.879 --> 00:12:52.080 infrared waves exactly together, they actually built the one way 264 00:12:52.080 --> 00:12:55.600 traffic valve for thermal energy. The heat comes in from 265 00:12:55.600 --> 00:12:58.720 the right, but the material completely denies the heat the 266 00:12:58.759 --> 00:13:01.919 ability to travel back to the right. It actively steers 267 00:13:01.919 --> 00:13:02.720 it out to the left. 268 00:13:02.799 --> 00:13:07.120 It fully breaks reciprocity. It decouples absorption from emission in 269 00:13:07.159 --> 00:13:09.519 a controllable, programmable way. 270 00:13:09.600 --> 00:13:12.120 Okay, my mind is thoroughly blown by the physics here, 271 00:13:12.159 --> 00:13:14.240 but I really have to ask cool for it. If 272 00:13:14.240 --> 00:13:17.240 we have a slanted pool table and rearranged furniture, why 273 00:13:17.320 --> 00:13:21.240 isn't this already inside my overheating laptop? Well, that's the catch, right, 274 00:13:21.320 --> 00:13:24.200 Because building a one way street for heat in a 275 00:13:24.279 --> 00:13:27.679 highly controlled laboratory setting is one thing to make it 276 00:13:27.759 --> 00:13:32.200 actually useful for consumer electronics or industrial systems. The Osaka 277 00:13:32.240 --> 00:13:36.960 researchers had to overcome two massive crippling flaws that plagued 278 00:13:37.039 --> 00:13:39.600 earlier experimental versions of this technology. 279 00:13:39.919 --> 00:13:43.240 That's entirely true. Breaking reciprocity has been a theoretical goal 280 00:13:43.279 --> 00:13:47.279 for a very long time, and early prototypes did exist. Yeah, 281 00:13:47.320 --> 00:13:50.320 but as you pointed out, they were incredibly fragile in 282 00:13:50.360 --> 00:13:53.360 how they operated. Yeah. The first massive hurdle the researchers 283 00:13:53.360 --> 00:13:55.919 overcame is what we call the angle problem. 284 00:13:56.000 --> 00:13:59.600 Earlier devices were extremely picky about how the thermal radiation 285 00:13:59.639 --> 00:14:00.679 actually hit them, right. 286 00:14:00.720 --> 00:14:06.000 Extremely picky. Previous experimental devices only exhibited this non reciprocal behavior, 287 00:14:06.039 --> 00:14:08.960 this one way heat flow if the thermal radiation arrived 288 00:14:08.960 --> 00:14:12.120 at very large, extreme grazing angles. 289 00:14:11.759 --> 00:14:13.759 Like trying to skip a stone across a pond. It 290 00:14:13.799 --> 00:14:16.519 only works if the rock comes in low and fast exactly. 291 00:14:16.600 --> 00:14:18.960 If the thermal radiation hit the material straight on or 292 00:14:19.000 --> 00:14:23.039 even close to perfectly perpendicular, the one way effect vanished entirely. 293 00:14:23.120 --> 00:14:26.399 It just broke down Yep, the device would basically revert 294 00:14:26.519 --> 00:14:30.080 back to normal symmetrical behavior. The heat would just bounce 295 00:14:30.159 --> 00:14:31.440 right back out the way it came. 296 00:14:31.399 --> 00:14:35.559 Which makes those early devices completely useless for real world cooling. 297 00:14:36.480 --> 00:14:40.000 Heat doesn't politely arrive at a perfect eighty degree grazing angle, 298 00:14:40.120 --> 00:14:43.639 not at all. A hot processor radiates heat isotropically. It 299 00:14:43.720 --> 00:14:46.919 blasts outward in every direction, all at once. You need 300 00:14:46.960 --> 00:14:48.799 a material that can catch it dead. 301 00:14:48.600 --> 00:14:51.960 On, and that is a major triumph of this new 302 00:14:52.120 --> 00:14:56.960 GST magneto optical device. It achieves what the researchers call 303 00:14:57.120 --> 00:15:00.759 giant non reciprocity even at near normal incidents. 304 00:15:00.840 --> 00:15:03.720 Okay, translating your normal incidents. That basically means the heat 305 00:15:03.799 --> 00:15:04.600 hits it straight on. 306 00:15:04.840 --> 00:15:08.360 Yes, normal incidents means the light hits the surface perfectly 307 00:15:08.440 --> 00:15:12.559 perpendicularly at a ninety degree angle to the surface. Achieving 308 00:15:12.679 --> 00:15:15.279 giant non reciprocity here means the one way effect is 309 00:15:15.320 --> 00:15:17.879 incredibly strong, not just barely detectable. 310 00:15:17.960 --> 00:15:18.919 So it actually works. 311 00:15:19.000 --> 00:15:21.960 This new device works brilliantly even when the thermal radiation 312 00:15:22.039 --> 00:15:24.279 hits it almost straight on. It doesn't need the grazing 313 00:15:24.360 --> 00:15:28.320 rock skip angle anymore. It functions in the messy multidirectional 314 00:15:28.360 --> 00:15:30.279 reality of actual heat emission. 315 00:15:30.360 --> 00:15:33.679 That alone takes this from a lab curiosity to a 316 00:15:33.720 --> 00:15:38.039 truly viable technology. But there was a second massive flaw 317 00:15:38.080 --> 00:15:40.120 with the old devices, and it has to do with 318 00:15:40.200 --> 00:15:41.720 memory and power consumption. 319 00:15:42.000 --> 00:15:43.759 Ah, yes, the power issue. 320 00:15:43.799 --> 00:15:46.759 From what I gather, the older experimental materials had a 321 00:15:46.840 --> 00:15:50.120 highly variable on and off switch, but much worse, they 322 00:15:50.240 --> 00:15:53.679 entirely forgot their state the exact second the electrical power 323 00:15:53.759 --> 00:15:54.080 was cut. 324 00:15:54.200 --> 00:15:57.679 They were volatile. They required a constant, uninterrupted supply of 325 00:15:57.720 --> 00:16:00.799 electrical energy just to maintain their megat magnetic fields and 326 00:16:00.840 --> 00:16:02.279 their asymmetrical properties. 327 00:16:02.320 --> 00:16:03.559 That seems counterproductive. 328 00:16:03.679 --> 00:16:06.200 It was the moment you turned off the power, the 329 00:16:06.200 --> 00:16:09.919 control mechanism would collapse and the material would instantly lose 330 00:16:10.000 --> 00:16:11.960 its one way heat flow capability. 331 00:16:12.159 --> 00:16:14.600 So it completely defeated the purpose. You were using a 332 00:16:14.639 --> 00:16:18.559 massive amount of electricity, which generates heat, just to power 333 00:16:18.559 --> 00:16:20.240 a device meant to manage heat. 334 00:16:20.200 --> 00:16:22.559 Exactly, an endless loop of inefficiency. 335 00:16:22.720 --> 00:16:25.120 Does this new device from the Osaka team solve that? 336 00:16:25.720 --> 00:16:25.799 So? 337 00:16:26.080 --> 00:16:29.000 Wait? Is this new device like a smart thermostat that 338 00:16:29.039 --> 00:16:32.360 physically remembers its molecular setting even after you pull the plug. 339 00:16:32.559 --> 00:16:35.440 What's fascinating here is that it solves it beautifully, and 340 00:16:35.480 --> 00:16:38.320 it all goes back to that GST phase change material 341 00:16:38.360 --> 00:16:42.679 we discussed earlier. Oh right. Because GST physically changes its 342 00:16:42.720 --> 00:16:48.240 crystalline structure, literally rearranging its atoms, that structural change remains 343 00:16:48.320 --> 00:16:51.679 permanently locked in even after the energy source used to 344 00:16:51.679 --> 00:16:54.039 trigger the change is completely removed. 345 00:16:53.679 --> 00:16:56.320 So it holds on to its programmed heat state indefinitely. 346 00:16:56.919 --> 00:16:59.679 Zero power required to keep the settings locked in. 347 00:17:00.039 --> 00:17:03.240 The structure itself is the memory. It's entirely non volatile. 348 00:17:03.519 --> 00:17:06.960 You apply a tiny brief optical or electrical pulse to 349 00:17:07.000 --> 00:17:10.039 set it to say, direct heat to the left, and 350 00:17:10.119 --> 00:17:13.279 it stays that way until you specifically apply another active 351 00:17:13.319 --> 00:17:14.319 pulse to change it back. 352 00:17:14.480 --> 00:17:15.720 That is incredible. 353 00:17:15.799 --> 00:17:18.359 It provides reversible on and off switching for heat flow 354 00:17:18.440 --> 00:17:21.759 without requiring any ongoing electrical power to maintain the state. 355 00:17:22.200 --> 00:17:24.759 So let's stick stock for a second. We now have 356 00:17:24.839 --> 00:17:28.720 a highly efficient composite material. It steers heat in one direction, 357 00:17:29.200 --> 00:17:31.880 It works when heat hits it straight on, and it 358 00:17:31.920 --> 00:17:35.319 physically remembers its program state without needing a constant drip 359 00:17:35.400 --> 00:17:36.119 of electricity. 360 00:17:36.200 --> 00:17:38.039 We've conquered the physics. 361 00:17:37.680 --> 00:17:39.720 Yes, So now we have to ask the big question, 362 00:17:40.039 --> 00:17:43.319 what is the ultimate endgame for this technology? Way does 363 00:17:43.359 --> 00:17:44.359 this actually take us? 364 00:17:44.799 --> 00:17:48.519 The landscape of applications is incredibly broad. On the most 365 00:17:48.559 --> 00:17:51.640 immediate practical level, we are looking at a new generation 366 00:17:51.799 --> 00:17:56.240 of highly efficient infrared emitters and advanced thermal energy devices, 367 00:17:56.480 --> 00:18:00.799 like what kind of devices think about space exploration? Managing 368 00:18:00.839 --> 00:18:04.599 thermal energy precisely can literally be a matter of life 369 00:18:04.680 --> 00:18:06.720 or death for a satellite. 370 00:18:06.200 --> 00:18:09.160 Oh sure, because if a satellite is facing the blazing 371 00:18:09.200 --> 00:18:11.599 sun on one side and the freezing vacuum of deep 372 00:18:11.680 --> 00:18:14.519 space on the other, being able to actively force the 373 00:18:14.559 --> 00:18:17.720 heat to only travel toward the deep space side without 374 00:18:17.799 --> 00:18:20.279 it reflecting back into the delicate instruments, I mean that 375 00:18:20.319 --> 00:18:22.920 would completely change how satellites are designed. 376 00:18:23.000 --> 00:18:27.279 Absolutely. The researchers also point heavily toward advanced optical sensors 377 00:18:27.680 --> 00:18:31.000 because you can control exactly how and where the material absorbs. 378 00:18:31.000 --> 00:18:34.839 In for red light, you could design sensors that are hyperdirectional. 379 00:18:34.480 --> 00:18:36.640 So they only look straight ahead exactly. 380 00:18:36.799 --> 00:18:40.480 They could perfectly ignore all background thermal noise coming from 381 00:18:40.519 --> 00:18:44.279 behind them and only focus on a specific target directly 382 00:18:44.319 --> 00:18:45.079 in front of them. 383 00:18:45.240 --> 00:18:47.759 But there is one application mentioned in the research that 384 00:18:47.799 --> 00:18:50.359 feels completely out of a science fiction novel, and that 385 00:18:50.440 --> 00:18:51.680 is photonic memory. 386 00:18:51.759 --> 00:18:56.759 Photonic memory is where this technology truly leaps into the future. Currently, 387 00:18:57.079 --> 00:19:00.119 almost all of our computing memory relies on store bring 388 00:19:00.200 --> 00:19:05.079 electrical charges. We trap microscopic electrons in tiny silicon cells 389 00:19:05.279 --> 00:19:07.279 to represent our digital ones and zeros. 390 00:19:07.440 --> 00:19:10.880 And as we just established, forcing billions of electrical charges 391 00:19:10.920 --> 00:19:15.400 through microscopic wires generates a massive amount of friction and heat, right, 392 00:19:15.480 --> 00:19:18.160 which brings us right back to our original problem. 393 00:19:18.279 --> 00:19:21.680 Exactly. But what if you completely remove the electrons from 394 00:19:21.680 --> 00:19:24.960 the equation? What if you stored information using light and heat? 395 00:19:25.039 --> 00:19:27.119 Let me make sure I'm following this. You could use 396 00:19:27.160 --> 00:19:33.000 this new GST magneto optical material to build actual memory chips. Yes, exactly, So, 397 00:19:33.079 --> 00:19:35.839 a digital one could physically be the state where the 398 00:19:35.920 --> 00:19:39.039 material is crystallized and directs heat to the right, and 399 00:19:39.079 --> 00:19:41.440 a digital zero could be the amorphous state where it 400 00:19:41.480 --> 00:19:42.519 directs heat to the left. 401 00:19:42.839 --> 00:19:46.559