WEBVTT 00:00:09.752 --> 00:00:14.070 The phenomenon you saw here for a brief moment 00:00:14.070 --> 00:00:20.459 is called quantum levitation and quantum locking. 00:00:20.459 --> 00:00:24.348 And the object that was levitating here 00:00:24.348 --> 00:00:26.349 is called a superconductor. 00:00:26.349 --> 00:00:31.941 Superconductivity is a quantum state of matter, 00:00:31.941 --> 00:00:36.198 and it occurs only below a certain critical temperature. NOTE Paragraph 00:00:36.198 --> 00:00:38.544 Now, it's quite an old phenomenon; 00:00:38.544 --> 00:00:40.310 it was discovered 100 years ago. 00:00:40.310 --> 00:00:42.436 However, only recently, 00:00:42.436 --> 00:00:44.798 due to several technological advancements, 00:00:44.798 --> 00:00:47.470 we are now able to demonstrate to you 00:00:47.470 --> 00:00:51.216 quantum levitation and quantum locking. NOTE Paragraph 00:00:51.216 --> 00:00:57.061 So, a superconductor is defined by two properties. 00:00:57.061 --> 00:01:00.517 The first is zero electrical resistance, 00:01:00.517 --> 00:01:07.406 and the second is the expulsion of a magnetic field from the interior of the superconductor. 00:01:07.406 --> 00:01:10.301 That sounds complicated, right? 00:01:10.301 --> 00:01:13.173 But what is electrical resistance? 00:01:13.173 --> 00:01:19.422 So, electricity is the flow of electrons inside a material. 00:01:19.422 --> 00:01:22.771 And these electrons, while flowing, 00:01:22.771 --> 00:01:25.459 they collide with the atoms, and in these collisions 00:01:25.459 --> 00:01:27.675 they lose a certain amount of energy. 00:01:27.675 --> 00:01:33.276 And they dissipate this energy in the form of heat, and you know that effect. 00:01:33.276 --> 00:01:39.195 However, inside a superconductor there are no collisions, 00:01:39.195 --> 00:01:43.887 so there is no energy dissipation. NOTE Paragraph 00:01:43.887 --> 00:01:46.868 It's quite remarkable. Think about it. 00:01:46.868 --> 00:01:51.947 In classical physics, there is always some friction, some energy loss. 00:01:51.947 --> 00:01:55.985 But not here, because it is a quantum effect. 00:01:56.016 --> 00:02:04.702 But that's not all, because superconductors don't like magnetic fields. 00:02:04.702 --> 00:02:09.019 So a superconductor will try to expel magnetic field from the inside, 00:02:09.019 --> 00:02:15.142 and it has the means to do that by circulating currents. 00:02:15.142 --> 00:02:18.132 Now, the combination of both effects -- 00:02:18.132 --> 00:02:24.132 the expulsion of magnetic fields and zero electrical resistance -- 00:02:24.132 --> 00:02:27.300 is exactly a superconductor. NOTE Paragraph 00:02:27.300 --> 00:02:31.516 But the picture isn't always perfect, as we all know, 00:02:31.516 --> 00:02:38.901 and sometimes strands of magnetic field remain inside the superconductor. 00:02:38.901 --> 00:02:42.555 Now, under proper conditions, which we have here, 00:02:42.555 --> 00:02:47.645 these strands of magnetic field can be trapped inside the superconductor. 00:02:47.645 --> 00:02:53.902 And these strands of magnetic field inside the superconductor, 00:02:53.902 --> 00:02:56.747 they come in discrete quantities. 00:02:56.747 --> 00:03:00.393 Why? Because it is a quantum phenomenon. It's quantum physics. 00:03:00.393 --> 00:03:04.243 And it turns out that they behave like quantum particles. NOTE Paragraph 00:03:04.243 --> 00:03:09.822 In this movie here, you can see how they flow one by one discretely. 00:03:09.822 --> 00:03:13.715 This is strands of magnetic field. These are not particles, 00:03:13.715 --> 00:03:18.010 but they behave like particles. 00:03:18.010 --> 00:03:22.204 So, this is why we call this effect quantum levitation and quantum locking. NOTE Paragraph 00:03:22.204 --> 00:03:28.267 But what happens to the superconductor when we put it inside a magnetic field? 00:03:28.267 --> 00:03:32.852 Well, first there are strands of magnetic field left inside, 00:03:32.852 --> 00:03:36.972 but now the superconductor doesn't like them moving around, 00:03:36.972 --> 00:03:40.420 because their movements dissipate energy, 00:03:40.420 --> 00:03:43.366 which breaks the superconductivity state. 00:03:43.366 --> 00:03:47.724 So what it actually does, it locks these strands, 00:03:47.724 --> 00:03:53.476 which are called fluxons, and it locks these fluxons in place. 00:03:53.476 --> 00:03:59.764 And by doing that, what it actually does is locking itself in place. 00:03:59.764 --> 00:04:08.980 Why? Because any movement of the superconductor will change their place, 00:04:08.980 --> 00:04:10.787 will change their configuration. NOTE Paragraph 00:04:10.787 --> 00:04:16.084 So we get quantum locking. And let me show you how this works. 00:04:16.084 --> 00:04:21.844 I have here a superconductor, which I wrapped up so it'd stay cold long enough. 00:04:21.844 --> 00:04:26.308 And when I place it on top of a regular magnet, 00:04:26.308 --> 00:04:30.180 it just stays locked in midair. NOTE Paragraph 00:04:30.180 --> 00:04:34.245 (Applause) NOTE Paragraph 00:04:34.245 --> 00:04:38.291 Now, this is not just levitation. It's not just repulsion. 00:04:38.291 --> 00:04:43.412 I can rearrange the fluxons, and it will be locked in this new configuration. 00:04:43.412 --> 00:04:47.436 Like this, or move it slightly to the right or to the left. 00:04:47.436 --> 00:04:55.187 So, this is quantum locking -- actually locking -- three-dimensional locking of the superconductor. 00:04:55.187 --> 00:04:57.347 Of course, I can turn it upside down, 00:04:57.347 --> 00:05:00.253 and it will remain locked. NOTE Paragraph 00:05:00.253 --> 00:05:09.475 Now, now that we understand that this so-called levitation is actually locking, 00:05:09.475 --> 00:05:13.789 Yeah, we understand that. 00:05:13.789 --> 00:05:18.051 You won't be surprised to hear that if I take this circular magnet, 00:05:18.051 --> 00:05:22.019 in which the magnetic field is the same all around, 00:05:22.019 --> 00:05:27.955 the superconductor will be able to freely rotate around the axis of the magnet. 00:05:27.955 --> 00:05:33.979 Why? Because as long as it rotates, the locking is maintained. 00:05:33.979 --> 00:05:40.005 You see? I can adjust and I can rotate the superconductor. 00:05:40.005 --> 00:05:46.667 We have frictionless motion. It is still levitating, but can move freely all around. NOTE Paragraph 00:05:46.667 --> 00:05:55.947 So, we have quantum locking and we can levitate it on top of this magnet. 00:05:55.947 --> 00:06:02.443 But how many fluxons, how many magnetic strands are there in a single disk like this? 00:06:02.443 --> 00:06:05.324 Well, we can calculate it, and it turns out, quite a lot. 00:06:05.324 --> 00:06:12.692 One hundred billion strands of magnetic field inside this three-inch disk. NOTE Paragraph 00:06:12.692 --> 00:06:16.796 But that's not the amazing part yet, because there is something I haven't told you yet. 00:06:16.796 --> 00:06:22.412 And, yeah, the amazing part is that this superconductor that you see here 00:06:22.412 --> 00:06:29.937 is only half a micron thick. It's extremely thin. 00:06:29.937 --> 00:06:39.499 And this extremely thin layer is able to levitate more than 70,000 times its own weight. 00:06:39.499 --> 00:06:45.332 It's a remarkable effect. It's very strong. NOTE Paragraph 00:06:45.332 --> 00:06:48.909 Now, I can extend this circular magnet, 00:06:48.909 --> 00:06:53.690 and make whatever track I want. 00:06:53.690 --> 00:06:57.619 For example, I can make a large circular rail here. 00:06:57.619 --> 00:07:04.502 And when I place the superconducting disk on top of this rail, 00:07:04.502 --> 00:07:08.611 it moves freely. NOTE Paragraph 00:07:08.611 --> 00:07:17.992 (Applause) NOTE Paragraph 00:07:17.992 --> 00:07:22.733 And again, that's not all. I can adjust its position like this, and rotate, 00:07:22.733 --> 00:07:29.174 and it freely moves in this new position. 00:07:29.174 --> 00:07:33.612 And I can even try a new thing; let's try it for the first time. 00:07:33.612 --> 00:07:39.556 I can take this disk and put it here, 00:07:39.556 --> 00:07:42.540 and while it stays here -- don't move -- 00:07:42.540 --> 00:07:49.098 I will try to rotate the track, 00:07:49.098 --> 00:07:51.397 and hopefully, if I did it correctly, 00:07:51.397 --> 00:07:53.540 it stays suspended. NOTE Paragraph 00:07:53.540 --> 00:08:02.989 (Applause) NOTE Paragraph 00:08:02.989 --> 00:08:09.830 You see, it's quantum locking, not levitation. 00:08:09.830 --> 00:08:13.965 Now, while I'll let it circulate for a little more, 00:08:13.965 --> 00:08:17.668 let me tell you a little bit about superconductors. 00:08:17.668 --> 00:08:23.214 Now -- (Laughter) -- 00:08:23.214 --> 00:08:30.237 So we now know that we are able to transfer enormous amount of currents inside superconductors, 00:08:30.237 --> 00:08:35.460 so we can use them to produce strong magnetic fields, 00:08:35.460 --> 00:08:40.646 such as needed in MRI machines, particle accelerators and so on. 00:08:40.646 --> 00:08:45.206 But we can also store energy using superconductors, 00:08:45.206 --> 00:08:47.095 because we have no dissipation. NOTE Paragraph 00:08:47.095 --> 00:08:54.277 And we could also produce power cables, to transfer enormous amounts of current between power stations. 00:08:54.277 --> 00:09:03.283 Imagine you could back up a single power station with a single superconducting cable. 00:09:03.283 --> 00:09:07.759 But what is the future of quantum levitation and quantum locking? 00:09:07.759 --> 00:09:14.898 Well, let me answer this simple question by giving you an example. 00:09:14.898 --> 00:09:21.311 Imagine you would have a disk similar to the one I have here in my hand, 00:09:21.311 --> 00:09:25.190 three-inch diameter, with a single difference. 00:09:25.190 --> 00:09:30.375 The superconducting layer, instead of being half a micron thin, 00:09:30.375 --> 00:09:33.463 being two millimeters thin, quite thin. 00:09:33.463 --> 00:09:44.198 This two-millimeter-thin superconducting layer could hold 1,000 kilograms, a small car, in my hand. 00:09:44.198 --> 00:09:47.494 Amazing. Thank you. NOTE Paragraph 00:09:47.494 --> 00:10:02.574 (Applause)