WEBVTT 1 00:00:03.399 --> 00:00:07.719 Welcome to Bedtime Astronomy. Explore the wonders of the cosmos 2 00:00:07.759 --> 00:00:12.279 with our soothing Bedtime Astronomie podcast. Each episode offers a 3 00:00:12.359 --> 00:00:16.320 gentle journey through the stars, planets, and beyond, perfect for 4 00:00:16.399 --> 00:00:20.239 unwinding after a long day. Let's travel through the mysteries 5 00:00:20.239 --> 00:00:22.440 of the universe as you drift off into a peaceful 6 00:00:22.480 --> 00:00:23.800 slumber under the night sky. 7 00:00:26.920 --> 00:00:30.039 Researchers at Harvard University have just figured out how to 8 00:00:30.120 --> 00:00:35.280 use quantum entanglement to detect impossibly weak single photon light 9 00:00:35.359 --> 00:00:39.520 signals across a one point five to five kilometer fiberlink. Yeah, 10 00:00:39.799 --> 00:00:42.320 just pause for a second and let the weight of 11 00:00:42.359 --> 00:00:44.520 that sink in. It sounds like something pulled straight from 12 00:00:44.560 --> 00:00:45.759 a hard sci fi novel. 13 00:00:45.920 --> 00:00:46.640 It really does. 14 00:00:46.719 --> 00:00:49.719 But it is a very real and very profound breakthrough 15 00:00:49.759 --> 00:00:52.719 that is going to fundamentally change how we see the cosmos. 16 00:00:53.000 --> 00:00:54.880 I want you to pose a scenario in your mind 17 00:00:54.960 --> 00:00:58.240 right now, Okay, Imagine you are trying to see the 18 00:00:58.359 --> 00:01:02.679 sharpest possible image of the deepest, darkest, most ancient parts 19 00:01:02.719 --> 00:01:03.840 of the universe. 20 00:01:03.640 --> 00:01:06.120 Like looking at the exact photon ring at the edge 21 00:01:06.120 --> 00:01:07.560 of a supermassive black hole. 22 00:01:07.719 --> 00:01:11.200 Right or perhaps you're trying to resolve the atmospheric absorption 23 00:01:11.319 --> 00:01:15.040 lines of a rocky exoplanet forty light years away. Up 24 00:01:15.120 --> 00:01:18.560 until now, our optical telescopes have hit a hard, unforgiving 25 00:01:18.560 --> 00:01:21.519 physical wall in terms of how clearly they could see. 26 00:01:21.560 --> 00:01:22.359 A literal wall. 27 00:01:22.480 --> 00:01:25.439 We've been trapped by the literal laws of classical physics, 28 00:01:25.920 --> 00:01:28.920 specifically the diffraction limits of monolithic mirrors. 29 00:01:29.040 --> 00:01:31.719 Right Because, no matter how perfectly we polish our beryllium 30 00:01:31.760 --> 00:01:35.400 or glass, or no matter how clever our active optics 31 00:01:35.439 --> 00:01:37.079 engineering gets. 32 00:01:36.920 --> 00:01:39.599 The universe had essentially placed a hard limit on our 33 00:01:39.680 --> 00:01:41.120 visual acuity exactly. 34 00:01:41.519 --> 00:01:46.879 But now by harnessing the absolute, strangest, most counterintuitive rules 35 00:01:46.879 --> 00:01:49.840 of quantum mechanics, we are figuring out how to cheat 36 00:01:49.879 --> 00:01:51.359 those physical limits entirely. 37 00:01:51.799 --> 00:01:54.799 What's fascinating here is this year scale of the ambition 38 00:01:54.959 --> 00:01:58.480 behind this. We are not talking about a marginal improvement 39 00:01:58.480 --> 00:02:00.239 in telescope technology, right. 40 00:02:00.319 --> 00:02:02.040 This isn't just an iterative update. 41 00:02:02.280 --> 00:02:05.319 No, we aren't talking about a new deconvolution algorithm that 42 00:02:05.400 --> 00:02:08.479 cleans up blurry pixels, or a slightly more reflective meta 43 00:02:08.560 --> 00:02:11.960 material coding for a mirror. No, this is a foundational, 44 00:02:12.080 --> 00:02:16.039 paradigm altering shift in optical physics. The research we are 45 00:02:16.039 --> 00:02:18.840 looking at published recently in the journal Nature by peterion 46 00:02:18.919 --> 00:02:20.199 Stass and his team. 47 00:02:19.960 --> 00:02:21.520 At Harvard amazing paper. 48 00:02:21.719 --> 00:02:24.560 It is the first real stepping stone toward a future 49 00:02:24.560 --> 00:02:27.560 that astrophysicists have been dreaming about for decades. 50 00:02:27.960 --> 00:02:30.879 They've successfully paved the way for completely new class of 51 00:02:30.919 --> 00:02:32.639 optical telescopes. 52 00:02:32.319 --> 00:02:36.280 Ones that will operate with totally unprecedented, world changing resolution. 53 00:02:37.199 --> 00:02:39.879 By proving that you can take a delicate, single photon 54 00:02:39.960 --> 00:02:44.039 of optical light and process its phase information across a 55 00:02:44.120 --> 00:02:47.199 vast distance using quantum entanglement. 56 00:02:46.759 --> 00:02:49.360 Which is just wild to think about, they. 57 00:02:49.280 --> 00:02:53.719 Have essentially provided the blueprint for optical telescope arrays that 58 00:02:53.800 --> 00:02:56.280 could one day be the size of entire continents. 59 00:02:56.439 --> 00:03:01.199 Okay, let's unpack this, because it truly appreciates how mind 60 00:03:01.199 --> 00:03:04.560 blowing this Harvard breakthrough is. We have to contextualize it 61 00:03:04.639 --> 00:03:09.479 within how astronomers currently push the boundaries of high resolution imaging. 62 00:03:09.639 --> 00:03:11.439 We have to look at the physical limits of building 63 00:03:11.479 --> 00:03:13.439 a single monolithic mirror, right. 64 00:03:13.240 --> 00:03:15.159 You can't just cast a piece of blast the size 65 00:03:15.199 --> 00:03:15.680 of a city. 66 00:03:15.719 --> 00:03:17.680 No, it would collapse under its own weight right. 67 00:03:17.520 --> 00:03:19.439 Away and warp from thermal gradients. 68 00:03:19.479 --> 00:03:22.280 Exactly, and it would be impossible to steer, which is 69 00:03:22.280 --> 00:03:26.000 why the field relies heavily on very long baseline. 70 00:03:25.560 --> 00:03:27.199 Interferometry or VLBI. 71 00:03:27.400 --> 00:03:30.039 Right. VLBI. Instead of one giant mirror, you build a 72 00:03:30.039 --> 00:03:32.240 network of spatially separated detectors. 73 00:03:32.439 --> 00:03:35.280 You point all of these individual observation stations at the 74 00:03:35.319 --> 00:03:37.240 exact same astrophysical object. 75 00:03:37.360 --> 00:03:41.360 Yeah, you collect the incoming electromagnetic waves simultaneously and then 76 00:03:41.400 --> 00:03:43.719 computationally or physically combine those waves. 77 00:03:43.800 --> 00:03:47.199 But the mechanics of how that combination actually works are 78 00:03:47.280 --> 00:03:48.840 incredibly demanding. 79 00:03:48.479 --> 00:03:52.479 Extremely demanding, and it relies heavily on Foura transform mathematics. Right. 80 00:03:52.560 --> 00:03:56.599 The ultimate genius of interferometry is what happens when you 81 00:03:56.639 --> 00:04:02.199 combine those separate signals correctly. By perfectly synchronizing the electromagnetic 82 00:04:02.240 --> 00:04:06.840 waves gathered from all those widely spaced locations, the interferometric 83 00:04:06.960 --> 00:04:12.319 array effectively creates a single giant virtual synthetic. 84 00:04:11.840 --> 00:04:13.719 Aperture, a virtual telescope. 85 00:04:13.800 --> 00:04:17.199 Yes, And the defining characteristic of that synthetic aperture, its 86 00:04:17.319 --> 00:04:20.959 angular resolution, isn't determined by the size of the individual 87 00:04:21.040 --> 00:04:21.839 collection dishes. 88 00:04:22.000 --> 00:04:24.040 It's determined by the distance exactly. 89 00:04:24.319 --> 00:04:27.319 It's determined by the maximum physical distance between the two 90 00:04:27.399 --> 00:04:30.800 antennas that are furthest apart in your network. That distance 91 00:04:30.879 --> 00:04:31.839 is called the baseline. 92 00:04:31.879 --> 00:04:34.920 So if you have two observation stations separated by ten 93 00:04:34.959 --> 00:04:36.519 thousand kilometers. 94 00:04:36.040 --> 00:04:38.680 And you can capture and combine the phase and amplitude 95 00:04:38.680 --> 00:04:40.600 of the incoming light perfectly. 96 00:04:40.160 --> 00:04:44.360 You achieve the angular resolution of a single continuous telescope 97 00:04:44.399 --> 00:04:47.040 mirror that is ten thousand kilometers wide. 98 00:04:47.120 --> 00:04:50.680 You are leveraging the interference patterns of the incoming waves 99 00:04:51.079 --> 00:04:54.399 to trick the universe into giving you the visual sharpness 100 00:04:54.480 --> 00:04:57.399 of a behemoth instrument without actually having to construct it. 101 00:04:57.480 --> 00:05:00.560 And we have seen the triumph of this specific technique 102 00:05:00.560 --> 00:05:03.399 in recent history. The prime example that comes to mind 103 00:05:03.560 --> 00:05:07.040 is the event Horizon telescope collaboration back in twenty nineteen 104 00:05:07.120 --> 00:05:10.800 oh absolutely, they gave us the first direct image. 105 00:05:10.480 --> 00:05:12.920 Of a black hole, the supermassive black hole at the 106 00:05:12.959 --> 00:05:14.800 center of the galaxy MESA eighty. 107 00:05:14.600 --> 00:05:18.519 Seven, right, that glowing asymmetrical ring of light surrounding the 108 00:05:18.639 --> 00:05:21.920 dark shadow of the event horizon. To get that image, 109 00:05:21.959 --> 00:05:24.000 they didn't use a single radio dish. 110 00:05:24.040 --> 00:05:27.360 No, they used a global network of observatories. 111 00:05:26.480 --> 00:05:29.399 Spanning from Hawaii to Chile, from Spain to the south 112 00:05:29.439 --> 00:05:30.480 Pole precisely. 113 00:05:30.759 --> 00:05:33.560 The MESAA eighty seven milestone is the textbook example of 114 00:05:33.639 --> 00:05:37.800 VLBI operating at its absolute maximum classical limit. They were 115 00:05:37.839 --> 00:05:41.800 looking at radio frequencies, specifically two hundred and thirty gigahertz. 116 00:05:41.399 --> 00:05:44.120 Which is crucial to point out, very crucial. 117 00:05:44.279 --> 00:05:47.720 To achieve the resolution necessary to see an object roughly 118 00:05:47.759 --> 00:05:50.600 the size of our solar system from fifty five million 119 00:05:50.680 --> 00:05:53.920 light years away, they had to effectively turn the entire 120 00:05:54.000 --> 00:05:56.959 Earth into one singular radio telescope. 121 00:05:57.360 --> 00:06:01.319 And the challenge there was data synchronization, massive data synchronization. 122 00:06:01.680 --> 00:06:04.279 They had to record the incoming radio waves at each 123 00:06:04.319 --> 00:06:08.439 independent station, timestamping every single fluctuation of the electric. 124 00:06:08.120 --> 00:06:11.839 Field using highly stable hydrogen maser atomic clocks. 125 00:06:12.000 --> 00:06:16.519 Right they recorded petabytes of this rawway formed data unto physical. 126 00:06:16.240 --> 00:06:19.360 Hard drives, loaded those hard drives onto airplanes and flew. 127 00:06:19.120 --> 00:06:23.480 Them to central supercomputing correlators at MIT Haystack and the 128 00:06:23.519 --> 00:06:25.360 Max Planck Institute. 129 00:06:24.879 --> 00:06:26.680 Because the files were just too big to send over 130 00:06:26.759 --> 00:06:27.879 the Internet exactly. 131 00:06:28.000 --> 00:06:31.399 The correlators then played those recordings back, aligning the atomic 132 00:06:31.480 --> 00:06:34.639 clock timestamps down to the picosecond and allowed the recorded 133 00:06:34.720 --> 00:06:37.399 radio waves to computationally interfere with one another. 134 00:06:37.360 --> 00:06:41.800 And that computationally generated interference pattern is what allowed them 135 00:06:41.839 --> 00:06:44.800 to extract the image of the black hole. I really 136 00:06:44.800 --> 00:06:46.639 want you to just sit with the sheer scale of 137 00:06:46.639 --> 00:06:50.079 that for a moment. Imagine a synthetic aperture that is 138 00:06:50.199 --> 00:06:53.279 literally as wide as the planet Earth looking out into 139 00:06:53.319 --> 00:06:53.759 the void. 140 00:06:53.959 --> 00:06:54.800 It's staggering. 141 00:06:54.920 --> 00:06:57.600 When we talk about angular resolution and astronomy, it is 142 00:06:57.680 --> 00:07:01.720 usually buried in units like microarcsect which feels incredibly. 143 00:07:01.279 --> 00:07:02.600 Abstract, very abstract. 144 00:07:02.720 --> 00:07:05.680 But when you realize that resolution is directly tied to 145 00:07:05.720 --> 00:07:10.079 the physical baseline of your instrument, the concept becomes massive 146 00:07:10.160 --> 00:07:10.839 and concrete. 147 00:07:11.079 --> 00:07:13.560 It's the difference between trying to resolve a grain of 148 00:07:13.600 --> 00:07:17.639 sand in New York while standing in Los Angeles versus 149 00:07:17.680 --> 00:07:21.279 looking through a lens that spans the entire North American continent. 150 00:07:21.439 --> 00:07:24.759 That is the power of interferometric baselines. So this brings 151 00:07:24.839 --> 00:07:27.000 up the obvious million dollar question, if we can do 152 00:07:27.040 --> 00:07:28.879 that with the event horizon telescope, If we. 153 00:07:28.879 --> 00:07:32.600 Can timestamp radio waves with atomic clocks, load them onto airplanes, 154 00:07:32.600 --> 00:07:34.720 and turn the Earth into a giant radio dish to 155 00:07:34.759 --> 00:07:36.199 see a black hole, why. 156 00:07:36.040 --> 00:07:40.040 Does optical astronomy require quantum mechanics. Why can't we just 157 00:07:40.160 --> 00:07:44.279 use the exact same VLBI technique to see visible or 158 00:07:44.319 --> 00:07:45.079 infrared light. 159 00:07:45.439 --> 00:07:48.199 That is exactly where the classical physics of the universe 160 00:07:48.399 --> 00:07:51.839 throws a massive roadblock in our path, and it fundamentally 161 00:07:51.879 --> 00:07:55.360 comes down to the frequency spectrum of the electromagnetic waves. 162 00:07:55.360 --> 00:07:56.639 We are trying to observe. 163 00:07:56.519 --> 00:07:58.079 The actual wavelength of the light. 164 00:07:58.279 --> 00:08:01.639 Yes, radio waves like the two hundred and thirty gigaherd 165 00:08:01.680 --> 00:08:05.639 signals the Event Horizon telescope is collecting have relatively long 166 00:08:05.680 --> 00:08:08.959 wavelengths on the order of millimeters because the waves are 167 00:08:09.000 --> 00:08:14.079 undulating relatively slowly. The electric field is oscillating at a 168 00:08:14.160 --> 00:08:17.800 rate that our fastest analog to digital converters can actually handle. 169 00:08:17.920 --> 00:08:19.800 We can physically measure the peats and valleys. 170 00:08:19.839 --> 00:08:22.160 We can directly measure the amplitude and the phase of 171 00:08:22.199 --> 00:08:24.759 the radio wave in real time. We can record its 172 00:08:24.800 --> 00:08:27.120 exact shape onto a hard drive because we can sample 173 00:08:27.160 --> 00:08:27.920 it fast enough. 174 00:08:28.079 --> 00:08:31.160 But when you move up the electromagnetic spectrum to visible 175 00:08:31.279 --> 00:08:34.720 or near infrared light, you are entering an entirely different 176 00:08:34.799 --> 00:08:37.759 regime of physics. The wavelengths of optical light are on 177 00:08:37.799 --> 00:08:40.759 the order of hundreds of nanometers right, which. 178 00:08:40.559 --> 00:08:43.679 Means the frequency is astronomically high. We are talking about 179 00:08:43.759 --> 00:08:44.519 hundreds of terra. 180 00:08:44.440 --> 00:08:46.960 Heerts, hundreds of trillions of times. 181 00:08:46.600 --> 00:08:50.360 Per second, exactly. An optical light wave is oscillating hundreds 182 00:08:50.399 --> 00:08:53.600 of trillions of times per second. There is no analog 183 00:08:53.720 --> 00:08:56.960 to digital converter on Earth and likely never will be 184 00:08:57.360 --> 00:09:00.559 that can sample an electric field at petahertz frequency and 185 00:09:00.639 --> 00:09:04.000 record its exact wave pattern onto a hard drive. It's 186 00:09:04.039 --> 00:09:07.320 just too fast, way too fast. You cannot simply timestamp 187 00:09:07.320 --> 00:09:10.240 a visible photon and save its phase to a disc 188 00:09:10.519 --> 00:09:12.519 to be correlated later on a supercomputer. 189 00:09:12.720 --> 00:09:15.519 Because we cannot digitize the electric field of optical light, 190 00:09:15.559 --> 00:09:17.840 we cannot use computational correlation. 191 00:09:18.279 --> 00:09:21.960 Instead, to do optical interferometry, we are forced to perform 192 00:09:22.000 --> 00:09:23.879 what is called direct interference. 193 00:09:24.000 --> 00:09:25.639 Direct physical interference. 194 00:09:25.720 --> 00:09:28.799 Yes, we have to physically take the actual delicate photons 195 00:09:28.840 --> 00:09:32.120 collected by Telescope A and physically overlap them with the 196 00:09:32.159 --> 00:09:34.480 delicate photons collected by Telescope. 197 00:09:34.039 --> 00:09:36.879 BA in real time on a physical beam splitter exam. 198 00:09:37.039 --> 00:09:39.559 So we can't record the light. We literally have to 199 00:09:39.600 --> 00:09:42.759 pipe it through optical cables to a central mixing room. 200 00:09:43.080 --> 00:09:46.279 But wait, if we use fiber optic cables to send 201 00:09:46.279 --> 00:09:50.200 the Internet across oceans without a problem. Why can't we 202 00:09:50.279 --> 00:09:54.000 just pipe visible starlight through those same cables to a 203 00:09:54.039 --> 00:09:55.120 central mixing station. 204 00:09:55.679 --> 00:09:59.559 Because of the massive difference between a robust, classical laser 205 00:09:59.639 --> 00:10:04.799 pulse used for telecommunications and the fragile single photon thermal 206 00:10:04.840 --> 00:10:06.840 states arriving from a distant star. 207 00:10:06.759 --> 00:10:08.879 They behave entirely differently completely. 208 00:10:09.000 --> 00:10:11.360 When you send Internet data across the Atlantic, you are 209 00:10:11.399 --> 00:10:14.440 firing billions of photons in a single pulse, and you 210 00:10:14.480 --> 00:10:18.600 have classical optical amplifiers repeating that signal every few dozen kilometers. 211 00:10:19.240 --> 00:10:23.039 But in optical astronomy you are dealing with impossibly faint starlight. 212 00:10:23.399 --> 00:10:26.519 You might be collecting just a handful of photons per second. 213 00:10:26.279 --> 00:10:29.679 Exactly, And you cannot amplify a quantum state without destroying 214 00:10:29.679 --> 00:10:30.600 its phase information. 215 00:10:30.759 --> 00:10:33.360 Oh right, that's prohibited by the note cloning theorem of 216 00:10:33.480 --> 00:10:34.919 quantum mechanics exactly. 217 00:10:35.120 --> 00:10:37.639 So you have to send that bare single photon through 218 00:10:37.679 --> 00:10:41.200 the silica glass of a fiber optic cable. And silica glass, 219 00:10:41.200 --> 00:10:43.039 no matter how pure, is lossy. 220 00:10:43.000 --> 00:10:44.840 It absorbs and scatters the light. 221 00:10:45.120 --> 00:10:49.039 Correct. The attenuation is brutal, even at the highly optimized 222 00:10:49.080 --> 00:10:52.200 telecom wavelength of one point five to five micrometers, you 223 00:10:52.279 --> 00:10:54.600 lose about half your photons every fifteen kilometers. 224 00:10:54.679 --> 00:10:55.039 Wow. 225 00:10:55.200 --> 00:10:58.320 At visible wavelengths, it's vastly worse. If you try to 226 00:10:58.360 --> 00:11:01.080 send a single photon from a star through just a 227 00:11:01.120 --> 00:11:05.080 few kilometers of fiber optic cable, the probability of it 228 00:11:05.279 --> 00:11:08.960 surviving the journey to that central mixing station drops exponentially. 229 00:11:09.080 --> 00:11:11.879 And remember, for interferometry to work, the photon from telescope 230 00:11:11.879 --> 00:11:15.039 A and the photon from telescope B both have to 231 00:11:15.080 --> 00:11:17.879 survive the journey and arrive at the central beam splitter 232 00:11:17.919 --> 00:11:19.559 at the exact same pekosecond. 233 00:11:19.639 --> 00:11:24.000 Because of this massive, unavoidable signal loss, traditional optical interferometer 234 00:11:24.080 --> 00:11:27.039 networks have been trapped at a very frustrating physical limit. 235 00:11:27.279 --> 00:11:30.080 They have been restricted to physical baselines of just about 236 00:11:30.080 --> 00:11:31.240 three hundred meters. 237 00:11:31.039 --> 00:11:33.120 And that three hundred meters wall is the bane of 238 00:11:33.159 --> 00:11:34.440 modern optical astronomy. 239 00:11:34.480 --> 00:11:36.879 You look at a facility like the very large telescope 240 00:11:36.919 --> 00:11:39.399 in the Atacoma Desert in Chile. They have four main 241 00:11:39.440 --> 00:11:42.879 telescopes and they can do optical interferometry by physically routing 242 00:11:42.919 --> 00:11:46.440 the starlight through underground vacuum tunnels to a central combining room. 243 00:11:46.679 --> 00:11:49.879 But the maximum distance between those telescopes is roughly one 244 00:11:50.000 --> 00:11:51.240 hundred and thirty meters. 245 00:11:51.480 --> 00:11:54.039 You simply cannot connect an optical telescope in Chili to 246 00:11:54.080 --> 00:11:55.519 an optical telescope in Hawaii. 247 00:11:55.720 --> 00:11:59.039 The stellar photons would scatter and die in the transoceanic 248 00:11:59.080 --> 00:12:02.279 cables long before they ever reached the central mixing room. 249 00:12:02.559 --> 00:12:06.240 So we have this agonizing situation where radio astronomers are 250 00:12:06.240 --> 00:12:10.919 building earth sized synthetic apertures, while optical astronomers are stuck 251 00:12:10.960 --> 00:12:13.399 with apertures the size of a football field, and. 252 00:12:13.320 --> 00:12:16.600 That restriction fundamentally throttles our understanding in the universe. 253 00:12:16.720 --> 00:12:20.080 If we could extend optical baselines from three hundred meters 254 00:12:20.120 --> 00:12:24.799 to say, one thousand kilometers, the angular resolution wouldn't. 255 00:12:24.440 --> 00:12:27.080 Just improve, No, it would open up entirely new fields 256 00:12:27.080 --> 00:12:31.080 of astrophysics. We could directly image the surface features of 257 00:12:31.200 --> 00:12:32.960 active galactic nuclei. 258 00:12:32.840 --> 00:12:37.320 Or resolve the kinematic structures of protoplanetary disks with subastronomical 259 00:12:37.399 --> 00:12:38.120 unit precision. 260 00:12:38.320 --> 00:12:40.480 But to do that you have to solve the physical 261 00:12:40.519 --> 00:12:43.559 routing problem. You have to somehow compare the phase of 262 00:12:43.559 --> 00:12:46.000 a photon. It telscope A with the phase of a 263 00:12:46.000 --> 00:12:49.000 photode at telescope B without ever sending the photons to 264 00:12:49.039 --> 00:12:50.639 a central location, which. 265 00:12:50.440 --> 00:12:54.039 Sounds like a paradox. How do you physically interfere two 266 00:12:54.080 --> 00:12:56.960 particles of light if you can't physically bring them to 267 00:12:57.000 --> 00:12:57.799 the same location. 268 00:12:58.200 --> 00:13:00.000 This is where we have to dive into the theory 269 00:13:00.000 --> 00:13:03.279 theoretical foundation that made the Harvard experiment. 270 00:13:02.879 --> 00:13:06.279 Possible, because before there was physical hardware, there was a 271 00:13:06.320 --> 00:13:09.639 mathematical blueprint to bypass the three hundred met a wall, 272 00:13:10.000 --> 00:13:12.759 generally referred to in the field as the twenty twelve 273 00:13:12.960 --> 00:13:15.159 Gotsman Genoine Kresser paper. 274 00:13:15.440 --> 00:13:17.879 Or what we can loosely call the Gotsman prophecy. 275 00:13:18.080 --> 00:13:19.120 I love that name. 276 00:13:19.279 --> 00:13:22.159 Yes. Daniel Gotsman and his colleagues looked at this strict 277 00:13:22.240 --> 00:13:26.960 optical baseline limit and proposed a mathematically audacious workaround. 278 00:13:27.120 --> 00:13:30.600 They realized that the fundamental bottleneck was the direct physical 279 00:13:30.639 --> 00:13:33.360 transportation of the thermal astronomical photon. 280 00:13:33.559 --> 00:13:35.919 So they asked a question rooted in the deepest, most 281 00:13:36.080 --> 00:13:40.159 counterintuitive aspects of quantum mechanics. What if you use quantum teleportation? 282 00:13:40.559 --> 00:13:44.120 What if you use pre shared quantum entanglement to extract 283 00:13:44.159 --> 00:13:47.919 the phase information of the starlight locally and then teleport 284 00:13:48.000 --> 00:13:50.879 that quantum state across the baseline. Hold on, let me 285 00:13:50.879 --> 00:13:54.200 stop you right there. When you say teleport the starlight's information, 286 00:13:54.320 --> 00:13:58.679 that immediately triggers a red flag for anyone familiar with relativity. Naturally, 287 00:13:58.879 --> 00:14:04.639 doesn't that imply instantaneous communication? Doesn't teleporting phase information violate 288 00:14:04.679 --> 00:14:05.279 the speed of light? 289 00:14:05.440 --> 00:14:07.559 It is a vital distinction to make, and the answer 290 00:14:07.600 --> 00:14:11.080 is no, it does not violate relativity. Quantum teleportation does 291 00:14:11.120 --> 00:14:14.440 not move physical matter instantaneously, nor does it allow for 292 00:14:14.519 --> 00:14:19.639 faster than light communication. What Gotsman proposed is using a resource, 293 00:14:20.480 --> 00:14:25.080 specifically an entangled pair of quantum states that is distributed 294 00:14:25.080 --> 00:14:27.519 between the two telescopes before the starlight. 295 00:14:27.159 --> 00:14:29.080 Even arrives pre shared entangle. 296 00:14:29.120 --> 00:14:32.639 In yes, if telescope A and telescope B share a 297 00:14:32.679 --> 00:14:37.639 pair of entangled particles, their quantum states are fundamentally mathematically correlated, 298 00:14:38.000 --> 00:14:41.639 regardless of the physical distance separating them. When the astronomical 299 00:14:41.639 --> 00:14:44.639 photon arrives at telescope A, it is forced to interact 300 00:14:44.639 --> 00:14:47.279 with the local half of that entangled pair through a 301 00:14:47.279 --> 00:14:50.279 specific process called a Bell state measurement. 302 00:14:49.960 --> 00:14:52.320 And this is where the phase information gets transferred without 303 00:14:52.360 --> 00:14:54.360 moving the original photon exactly. 304 00:14:55.120 --> 00:14:59.480 The Bell state measurement at Telescope A destroys the original 305 00:14:59.480 --> 00:15:03.320 astronomy photon, it consumes it, but in doing so it 306 00:15:03.399 --> 00:15:07.600 intrinsically entangles the incoming starlight state with the pre shared 307 00:15:07.720 --> 00:15:09.159 entanglement resource. 308 00:15:08.799 --> 00:15:11.519 Because the other half of that entangled resource is sitting 309 00:15:11.559 --> 00:15:12.559 over at telescope B. 310 00:15:12.879 --> 00:15:15.799 Right, So, the quantum state of the astronomical photon, its 311 00:15:15.840 --> 00:15:18.919 exact phase and amplitude at the moment it arrived, is 312 00:15:18.960 --> 00:15:21.720 effectively transferred to the quantum memory at telescope B. 313 00:15:22.240 --> 00:15:23.879 But causality is maintained. 314 00:15:24.000 --> 00:15:27.240 Right, Yes, because the actual physical data regarding the outcome 315 00:15:27.279 --> 00:15:30.120 of the measurement at Telescope A still has to be 316 00:15:30.120 --> 00:15:34.120 sent to Telescope B over a standard classical internet connection. 317 00:15:34.000 --> 00:15:35.679 Which is limited by the speed of light. 318 00:15:35.840 --> 00:15:39.759 So causality is perfectly preserved. But the crucial breakthrough is 319 00:15:39.799 --> 00:15:43.080 that the delicate quantum phase information didn't have to survive 320 00:15:43.159 --> 00:15:45.799 a brutal journey through a lossy optical fiber. 321 00:15:46.039 --> 00:15:48.320 It bypassed the environment completely. 322 00:15:48.879 --> 00:15:52.279 Okay, let's unpack this because the implications are staggering. You're 323 00:15:52.360 --> 00:15:55.679 essentially saying that if we can create an invisible entangled 324 00:15:55.720 --> 00:16:00.000 bridge between two telescopes. The starlight only has to travel 325 00:16:00.120 --> 00:16:03.360 from deep space down to the local telescope dish. 326 00:16:03.600 --> 00:16:06.799 It hits, the dish, interacts with the local entangled particle, 327 00:16:06.919 --> 00:16:10.559 and its essential quantum signature is instantly mapped onto the 328 00:16:10.639 --> 00:16:11.639 other side of the network. 329 00:16:11.759 --> 00:16:15.159 It completely negates the photon loss problem of fiber optic 330 00:16:15.200 --> 00:16:18.480 cables entirely. But if Gotsman and his team proved the 331 00:16:18.519 --> 00:16:22.639 math for this continuous variable quantum teleportation back in twenty twelve, 332 00:16:23.000 --> 00:16:25.919 why did it remain a chalk poor dream for over 333 00:16:25.960 --> 00:16:28.799 a decade. If the math works, why didn't we build 334 00:16:28.840 --> 00:16:29.639 it immediately? 335 00:16:30.200 --> 00:16:33.519 If we connect this to the bigger picture, the mathematical 336 00:16:33.519 --> 00:16:37.720 elegance of quantum teleportation belies the absolute nightmare of engineering 337 00:16:37.720 --> 00:16:38.919 it in physical reality. 338 00:16:39.080 --> 00:16:41.320 The hardware just wasn't there, not even close. 339 00:16:41.639 --> 00:16:45.039 Gotsman knew that the practical roadblocks were immense. To make 340 00:16:45.080 --> 00:16:47.279 this work for astronomy, you need a physical system that 341 00:16:47.320 --> 00:16:49.879 can do three exceedingly difficult things simultaneously. 342 00:16:49.960 --> 00:16:52.759 Okay, what's the first. First, it must act as an 343 00:16:52.799 --> 00:16:58.039 optical interface to catch the incredibly weak, randomly arriving thermal 344 00:16:58.080 --> 00:17:01.240 photons from the star that makes sense. Second, it must 345 00:17:01.240 --> 00:17:05.680 be able to generate and hold robust quantum entanglement over 346 00:17:05.799 --> 00:17:07.680 long physical distances. 347 00:17:07.240 --> 00:17:08.559 Which is incredibly hard. 348 00:17:08.839 --> 00:17:12.359 And third, it has to store that delicate quantum state 349 00:17:12.440 --> 00:17:15.640 in a memory long enough for the classical data of 350 00:17:15.680 --> 00:17:17.440 the measurement to travel across the. 351 00:17:17.400 --> 00:17:19.720 Network right because of the speed of light limit on 352 00:17:19.799 --> 00:17:21.200 that classical data channel. 353 00:17:21.319 --> 00:17:26.720 Exactly in twenty twelve, deterministic entanglement generation rates between distant 354 00:17:26.720 --> 00:17:30.839 physical nodes were abysmal. The technology simply did not exist 355 00:17:30.880 --> 00:17:34.400 to maintain a stable, high fidelity quantum memory that could 356 00:17:34.480 --> 00:17:37.119 interface with visible light at the rates required to do 357 00:17:37.240 --> 00:17:38.559 actual astrophysics. 358 00:17:38.720 --> 00:17:41.160 It was a beautiful protocol waiting for the hardware to 359 00:17:41.200 --> 00:17:43.880 catch up, which perfectly sets the stage for bringing our 360 00:17:43.920 --> 00:17:46.319 timeline right back to the present day and focusing on 361 00:17:46.359 --> 00:17:50.160 the physical hardware that Peter Jonstass and his team at Harvard. 362 00:17:50.160 --> 00:17:53.839 Actually built because they took Gosman's theoretical protocol and dragged 363 00:17:53.839 --> 00:17:56.400 it kicking and screaming into physical reality. 364 00:17:56.480 --> 00:18:00.480 To do that, they didn't rely on standard silicon computing chips, no, 365 00:18:01.079 --> 00:18:04.279 and they certainly weren't using bulk optical mirrors. They had 366 00:18:04.279 --> 00:18:08.440 to engineer a highly specific quantum memory using what are 367 00:18:08.440 --> 00:18:13.160 called silicon vacancy centers embedded in diamond nanocavities. And I 368 00:18:13.200 --> 00:18:15.720 want to get deeply into the solid state physics here. 369 00:18:15.880 --> 00:18:17.079 It's fascinating physics. 370 00:18:17.279 --> 00:18:21.079 Why diamond and what exactly is a silicon vacancy center. 371 00:18:21.240 --> 00:18:23.920 To understand the hardware, we have to look at the crystallography. Okay. 372 00:18:24.799 --> 00:18:30.279 A pure diamond is a rigid, perfectly repeating lattice of 373 00:18:30.519 --> 00:18:34.400 carbon atoms bonded in a tetrahedral structure. It has a 374 00:18:34.480 --> 00:18:37.880 very wide electronic band gap, meaning it is highly transparent, 375 00:18:38.400 --> 00:18:41.680 and it has an extremely rigid lattice, which means the 376 00:18:41.720 --> 00:18:44.640 speed of sound inside a diamond is very high, and 377 00:18:44.680 --> 00:18:47.720 the thermal vibrations the phonons are tightly. 378 00:18:47.440 --> 00:18:49.519 Constrained, so it's a very quiet material. 379 00:18:49.599 --> 00:18:53.200 Computationally speaking, This makes diamond an exceptionally quiet environment in 380 00:18:53.240 --> 00:18:57.279 cryogenic temperatures. But the Harvard researchers don't want a perfect. 381 00:18:57.000 --> 00:18:59.480 Diamond because a perfect diamond is inert. 382 00:18:59.480 --> 00:19:01.839 Exactly, it doesn't interact with light in the way we need. 383 00:19:02.119 --> 00:19:05.119 So they use a process like chemical vapor deposition to 384 00:19:05.319 --> 00:19:08.680 grow the diamond, and during that process or through targeted 385 00:19:08.680 --> 00:19:13.720 ion beam implantation, they intentionally introduce a specific microscopic defect. 386 00:19:13.799 --> 00:19:15.759 They break the perfect lattice. 387 00:19:15.400 --> 00:19:18.279 They knock out two adjacent carbon atoms from the lattice, 388 00:19:18.400 --> 00:19:21.319 and they insert a single larger silicon atom right in 389 00:19:21.359 --> 00:19:22.480 the middle of that empty space. 390 00:19:22.640 --> 00:19:25.599 So you have a silicon atom sitting suspended between two 391 00:19:25.920 --> 00:19:27.079 missing carbon spots. 392 00:19:27.119 --> 00:19:31.480 Precisely. That specific geometric arrangement is the silicon vacancy or 393 00:19:31.480 --> 00:19:34.559 cieves center, and it has a unique property that is 394 00:19:34.640 --> 00:19:38.960 absolutely vital for this experiment inversion symmetry. Yes, inversion symmetry. 395 00:19:39.079 --> 00:19:42.440 Because the silicon atom sits perfectly centered between the two vacancies, 396 00:19:42.759 --> 00:19:46.240 the defect is highly protected from local chaotic electric field 397 00:19:46.319 --> 00:19:48.799 fluctuations in the surrounding diamond crystal. 398 00:19:48.960 --> 00:19:51.599 In quantum mechanics, we call this spectral stability. 399 00:19:51.880 --> 00:19:54.920 It means that the optical transitions of this defect, the 400 00:19:55.000 --> 00:19:58.240 exact frequencies of light it will absorb or Emit remain 401 00:19:58.400 --> 00:20:02.160