title
Superconductivity Explained | Jeffrey Shainline and Lex Fridman

description
Lex Fridman Podcast full episode: https://www.youtube.com/watch?v=EwueqdgIvq4 Please support this podcast by checking out our sponsors: - Stripe: https://stripe.com - Codecademy: https://codecademy.com and use code LEX to get 15% off - Linode: https://linode.com/lex to get $100 free credit - BetterHelp: https://betterhelp.com/lex to get 10% off GUEST BIO: Jeffrey Shainline is a physicist at NIST working on. Note: Opinions expressed by Jeff do not represent NIST. PODCAST INFO: Podcast website: https://lexfridman.com/podcast Apple Podcasts: https://apple.co/2lwqZIr Spotify: https://spoti.fi/2nEwCF8 RSS: https://lexfridman.com/feed/podcast/ Full episodes playlist: https://www.youtube.com/playlist?list=PLrAXtmErZgOdP_8GztsuKi9nrraNbKKp4 Clips playlist: https://www.youtube.com/playlist?list=PLrAXtmErZgOeciFP3CBCIEElOJeitOr41 SOCIAL: - Twitter: https://twitter.com/lexfridman - LinkedIn: https://www.linkedin.com/in/lexfridman - Facebook: https://www.facebook.com/lexfridman - Instagram: https://www.instagram.com/lexfridman - Medium: https://medium.com/@lexfridman - Reddit: https://reddit.com/r/lexfridman - Support on Patreon: https://www.patreon.com/lexfridman

detail
{'title': 'Superconductivity Explained | Jeffrey Shainline and Lex Fridman', 'heatmap': [], 'summary': 'Covers superconductivity in semiconductors, conventional superconductors like niobium, josephson junctions for current flow and logic operations, and the speed and limitations of superconducting logic, highlighting their potential in superconducting circuits and their impracticality in consumer electronics.', 'chapters': [{'end': 188.861, 'segs': [{'end': 90.813, 'src': 'embed', 'start': 3.064, 'weight': 0, 'content': [{'end': 4.346, 'text': "Okay, so let's return.", 'start': 3.064, 'duration': 1.282}, {'end': 7.511, 'text': 'you mentioned this word superconductivity.', 'start': 4.346, 'duration': 3.165}, {'end': 10.215, 'text': "so what does that have to do with what we're talking about??", 'start': 7.511, 'duration': 2.704}, {'end': 21.931, 'text': 'Right, okay, so in a semiconductor, as I tried to describe a second ago, you can sort of in induced currents by applying voltages,', 'start': 10.515, 'duration': 11.416}, {'end': 27.155, 'text': 'and those have sort of typical properties that you would expect from some kind of a conductor.', 'start': 21.931, 'duration': 5.224}, {'end': 32.06, 'text': "Those electrons, they don't just flow perfectly without dissipation.", 'start': 27.195, 'duration': 4.865}, {'end': 38.465, 'text': "If an electron collides with an imperfection in the lattice or another electron, it's going to slow down, it's going to lose its momentum.", 'start': 32.24, 'duration': 6.225}, {'end': 42.909, 'text': 'So you have to keep applying that voltage in order to keep the current flowing.', 'start': 38.665, 'duration': 4.244}, {'end': 45.091, 'text': 'In a superconductor, something different happens.', 'start': 43.27, 'duration': 1.821}, {'end': 50.016, 'text': 'get a current to start flowing, it will continue to flow indefinitely.', 'start': 46.072, 'duration': 3.944}, {'end': 51.598, 'text': "There's no dissipation.", 'start': 50.056, 'duration': 1.542}, {'end': 53.4, 'text': "So that's crazy.", 'start': 51.698, 'duration': 1.702}, {'end': 58.566, 'text': 'How does that happen? Well, it happens at low temperature, and this is crucial.', 'start': 53.46, 'duration': 5.106}, {'end': 61.949, 'text': 'It has to be a quite low temperature.', 'start': 58.646, 'duration': 3.303}, {'end': 67.555, 'text': "And what I'm talking about there for essentially all of our conversation.", 'start': 62.03, 'duration': 5.525}, {'end': 76.122, 'text': "I'm going to be talking about conventional superconductors, sometimes called low TC superconductors, low critical temperature superconductors.", 'start': 67.555, 'duration': 8.567}, {'end': 83.708, 'text': 'And so those materials have to be in at a temperature around, say around four Kelvin.', 'start': 76.943, 'duration': 6.765}, {'end': 88.932, 'text': 'I mean their critical temperature might be 10 Kelvin, something like that, but you want to operate them in around four Kelvin,', 'start': 83.728, 'duration': 5.204}, {'end': 90.813, 'text': 'four degrees above absolute zero.', 'start': 88.932, 'duration': 1.881}], 'summary': 'Superconductors allow current flow without dissipation at low temperatures, around 4 kelvin.', 'duration': 87.749, 'max_score': 3.064, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/2FdlMnAwi84/pics/2FdlMnAwi843064.jpg'}, {'end': 188.861, 'src': 'embed', 'start': 118.362, 'weight': 2, 'content': [{'end': 122.664, 'text': "let's say niobium is a very typical superconductor.", 'start': 118.362, 'duration': 4.302}, {'end': 128.685, 'text': 'If I had a block of niobium here and we cooled it below its critical temperature,', 'start': 122.784, 'duration': 5.901}, {'end': 134.527, 'text': 'all of the electrons in that superconducting state would be in one coherent quantum state.', 'start': 128.685, 'duration': 5.842}, {'end': 141.549, 'text': 'The wave function of that state is described in terms of all of the particles simultaneously,', 'start': 135.627, 'duration': 5.922}, {'end': 148.591, 'text': 'but it extends across macroscopic dimensions the size of whatever block of that material I have sitting here.', 'start': 141.549, 'duration': 7.042}, {'end': 158.194, 'text': "And the way this occurs is that let's try to be a little bit light on the technical details, but essentially the electrons coordinate with each other.", 'start': 149.091, 'duration': 9.103}, {'end': 166.159, 'text': "They are able to, in this macroscopic quantum state, they're able to sort of one can quickly take the place of the other.", 'start': 158.214, 'duration': 7.945}, {'end': 167.521, 'text': "You can't tell electrons apart.", 'start': 166.179, 'duration': 1.342}, {'end': 169.464, 'text': "They're what's known as identical particles.", 'start': 167.561, 'duration': 1.903}, {'end': 176.074, 'text': 'So if this electron runs into a defect that would otherwise cause it to scatter,', 'start': 169.524, 'duration': 6.55}, {'end': 183.974, 'text': "it can just sort of almost miraculously avoid that defect because it's not really in that location.", 'start': 176.074, 'duration': 7.9}, {'end': 188.861, 'text': "It's part of a macroscopic quantum state and the entire quantum state was not scattered by that defect.", 'start': 184.034, 'duration': 4.827}], 'summary': 'Niobium, a typical superconductor, exhibits macroscopic quantum behavior with electrons in a coherent state extending across its dimensions.', 'duration': 70.499, 'max_score': 118.362, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/2FdlMnAwi84/pics/2FdlMnAwi84118362.jpg'}], 'start': 3.064, 'title': 'Superconductivity in semiconductors', 'summary': 'Discusses the concept of superconductivity in semiconductors, where induced currents flow indefinitely at low temperatures, contrasting with typical semiconductor behavior. it also covers conventional superconductors operating at around four kelvin and niobium as a typical superconductor.', 'chapters': [{'end': 67.555, 'start': 3.064, 'title': 'Superconductivity in semiconductors', 'summary': 'Explains the concept of superconductivity in semiconductors, where at low temperatures, induced currents flow indefinitely without dissipation, contrasting with typical semiconductor behavior.', 'duration': 64.491, 'highlights': ['Superconductivity in semiconductors allows for induced currents to flow indefinitely at low temperatures, with no dissipation, in contrast to typical semiconductor behavior.', 'In semiconductors, induced currents experience dissipation due to electron collisions, requiring continuous voltage application to maintain flow.', 'Superconductivity in semiconductors occurs at low temperatures, enabling the indefinite flow of induced currents.']}, {'end': 188.861, 'start': 67.555, 'title': 'Conventional superconductors', 'summary': 'Discusses conventional superconductors, also known as low tc superconductors, which operate at around four kelvin, enabling electrons to settle into a macroscopic quantum state, allowing them to coordinate and avoid scattering, with niobium being a typical superconductor.', 'duration': 121.306, 'highlights': ['Conventional superconductors operate at around four Kelvin, allowing electrons to settle into a macroscopic quantum state. The critical temperature for conventional superconductors is around four Kelvin, enabling electrons to settle into a macroscopic quantum state.', 'Niobium is a very typical superconductor. Niobium is a commonly used superconductor material.', 'Electrons in the superconducting state would be in one coherent quantum state, described in terms of all the particles simultaneously. In the superconducting state, all electrons are in one coherent quantum state, described in terms of all particles simultaneously.', 'Electrons in a macroscopic quantum state are able to coordinate with each other, allowing one to quickly take the place of the other, as they are identical particles. Electrons in a macroscopic quantum state can coordinate with each other, allowing one to quickly take the place of the other, due to being identical particles.', 'Electrons in a macroscopic quantum state can avoid scattering by defects, as the entire quantum state was not scattered by that defect. In a macroscopic quantum state, electrons can avoid scattering by defects, as the entire quantum state was not affected by the defect.']}], 'duration': 185.797, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/2FdlMnAwi84/pics/2FdlMnAwi843064.jpg', 'highlights': ['Superconductivity in semiconductors allows for induced currents to flow indefinitely at low temperatures, with no dissipation, in contrast to typical semiconductor behavior.', 'Conventional superconductors operate at around four Kelvin, allowing electrons to settle into a macroscopic quantum state.', 'Niobium is a very typical superconductor, commonly used as a superconductor material.', 'Superconductivity in semiconductors occurs at low temperatures, enabling the indefinite flow of induced currents.', 'The critical temperature for conventional superconductors is around four Kelvin, enabling electrons to settle into a macroscopic quantum state.', 'In the superconducting state, all electrons are in one coherent quantum state, described in terms of all particles simultaneously.', 'Electrons in a macroscopic quantum state can coordinate with each other, allowing one to quickly take the place of the other, due to being identical particles.', 'Electrons in a macroscopic quantum state can avoid scattering by defects, as the entire quantum state was not affected by the defect.', 'In semiconductors, induced currents experience dissipation due to electron collisions, requiring continuous voltage application to maintain flow.']}, {'end': 426.956, 'segs': [{'end': 238.513, 'src': 'embed', 'start': 212.301, 'weight': 0, 'content': [{'end': 218.144, 'text': 'you can do usual things like make wires out of it so you can get current to flow in a straight line on a chip,', 'start': 212.301, 'duration': 5.843}, {'end': 223.606, 'text': 'but you can also make other devices that perform different kinds of operations.', 'start': 218.144, 'duration': 5.462}, {'end': 228.407, 'text': "Some of them are kind of logic operations like you'd get in a transistor.", 'start': 223.646, 'duration': 4.761}, {'end': 238.513, 'text': 'The most common or the most I would say diverse in its utility component is a Josephson junction.', 'start': 228.528, 'duration': 9.985}], 'summary': 'Superconducting materials enable diverse operations, including logic operations and josephson junctions for various applications.', 'duration': 26.212, 'max_score': 212.301, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/2FdlMnAwi84/pics/2FdlMnAwi84212301.jpg'}, {'end': 287.588, 'src': 'embed', 'start': 264.097, 'weight': 7, 'content': [{'end': 271.38, 'text': "I'm not sure how concerned to be with semantics, but let me just briefly say what a Josephson junction is,", 'start': 264.097, 'duration': 7.283}, {'end': 273.461, 'text': 'and we can talk about different ways that they can be used.', 'start': 271.38, 'duration': 2.081}, {'end': 281.485, 'text': 'Basically, if you have a superconducting wire and then a small gap of a different material,', 'start': 274.062, 'duration': 7.423}, {'end': 287.588, 'text': "that's not superconducting an insulator or normal metal and then another superconducting wire on the other side.", 'start': 281.485, 'duration': 6.103}], 'summary': 'Josephson junctions consist of superconducting wires with a small gap of different material, and can be used in various ways.', 'duration': 23.491, 'max_score': 264.097, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/2FdlMnAwi84/pics/2FdlMnAwi84264097.jpg'}, {'end': 349.781, 'src': 'embed', 'start': 316.925, 'weight': 3, 'content': [{'end': 322.286, 'text': 'So you can imagine, suppose you had a loop setup that had one of those weak links in the loop.', 'start': 316.925, 'duration': 5.361}, {'end': 327.388, 'text': "Current would flow in that loop independent, even if you hadn't applied a voltage to it.", 'start': 323.067, 'duration': 4.321}, {'end': 328.788, 'text': "And that's called the Josephson effect.", 'start': 327.408, 'duration': 1.38}, {'end': 330.389, 'text': "So the fact that there's this,", 'start': 328.888, 'duration': 1.501}, {'end': 337.433, 'text': 'The phase difference in the quantum wave function from one side of the tunneling barrier to the other induces current to flow.', 'start': 331.249, 'duration': 6.184}, {'end': 340.255, 'text': 'So how does you change state? Right, exactly.', 'start': 337.533, 'duration': 2.722}, {'end': 341.335, 'text': 'So how do you change state?', 'start': 340.315, 'duration': 1.02}, {'end': 349.781, 'text': "Now picture if I have a current bias coming down this line of my circuit and there's a Josephson junction right in the middle of it.", 'start': 341.375, 'duration': 8.406}], 'summary': 'Josephson effect induces current flow in quantum circuits with weak links', 'duration': 32.856, 'max_score': 316.925, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/2FdlMnAwi84/pics/2FdlMnAwi84316925.jpg'}, {'end': 411.949, 'src': 'embed', 'start': 382.994, 'weight': 4, 'content': [{'end': 385.856, 'text': 'So in the Josephson junction, the same thing happens.', 'start': 382.994, 'duration': 2.862}, {'end': 391.4, 'text': "I can bias it above its critical current, and then what it's gonna do, it's going to add a..", 'start': 385.996, 'duration': 5.404}, {'end': 395.982, 'text': 'a quantized amount of current into that loop.', 'start': 392.961, 'duration': 3.021}, {'end': 402.585, 'text': "And what I mean by quantized is it's going to come in discrete packets with a well-defined value of current.", 'start': 396.002, 'duration': 6.583}, {'end': 411.949, 'text': 'So in the vernacular of of some people working in this community, you would say you pop a flux on into the loop.', 'start': 403.045, 'duration': 8.904}], 'summary': 'Josephson junction adds quantized current in discrete packets.', 'duration': 28.955, 'max_score': 382.994, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/2FdlMnAwi84/pics/2FdlMnAwi84382994.jpg'}], 'start': 188.881, 'title': 'Superconductivity and josephson junctions', 'summary': 'Introduces superconductivity and its application in making wires for current flow, along with the diverse utility of josephson junctions in performing logic operations and serving as gates for building complex circuits. it also discusses the structure, current-voltage characteristics, and potential applications of josephson junctions, offering insights into their potential in superconducting circuits.', 'chapters': [{'end': 263.436, 'start': 188.881, 'title': 'Superconductivity and josephson junctions', 'summary': 'Introduces superconductivity and its application in making wires for current flow, along with the diverse utility of josephson junctions in performing logic operations and serving as gates for building complex circuits.', 'duration': 74.555, 'highlights': ['Josephson junctions serve as gates and can perform logic operations analogous to transistors.', 'Superconductivity allows current to flow without dissipation, enabling the creation of wires for straight-line current flow on a chip.', 'Josephson junctions are the go-to component for circuit engineers to build up complexity in circuits.']}, {'end': 426.956, 'start': 264.097, 'title': 'Josephson junction and its applications', 'summary': 'Discusses josephson junctions, explaining their structure and the unusual current-voltage characteristics they exhibit, as well as the josephson effect and the ability to add quantized amounts of current to a superconducting loop, providing insights into their potential applications in superconducting circuits.', 'duration': 162.859, 'highlights': ['A Josephson junction is formed by a superconducting wire, a small gap of a different material (insulator or normal metal), and another superconducting wire, which exhibits unusual current-voltage characteristics.', 'The Josephson effect allows current to flow in a loop with a weak link, even without an applied voltage, induced by the phase difference in the quantum wave function across the tunneling barrier.', "Exceeding the critical current of a Josephson junction allows the addition of quantized amounts of current into a superconducting loop, referred to as 'popping a flux on,' with well-defined values of current.", 'The ability to add quantized amounts of current to a loop via Josephson junctions has potential applications in superconducting circuits and could facilitate the development of new technologies.', 'Josephson junctions have the potential to change the state of superconducting loops by exceeding their critical current, allowing the addition of discrete packets of current with well-defined values.']}], 'duration': 238.075, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/2FdlMnAwi84/pics/2FdlMnAwi84188881.jpg', 'highlights': ['Superconductivity enables the creation of wires for straight-line current flow on a chip.', 'Josephson junctions serve as gates and can perform logic operations analogous to transistors.', 'Josephson junctions are the go-to component for circuit engineers to build up complexity in circuits.', 'The Josephson effect allows current to flow in a loop with a weak link, even without an applied voltage, induced by the phase difference in the quantum wave function across the tunneling barrier.', "Exceeding the critical current of a Josephson junction allows the addition of quantized amounts of current into a superconducting loop, referred to as 'popping a flux on,' with well-defined values of current.", 'The ability to add quantized amounts of current to a loop via Josephson junctions has potential applications in superconducting circuits and could facilitate the development of new technologies.', 'Josephson junctions have the potential to change the state of superconducting loops by exceeding their critical current, allowing the addition of discrete packets of current with well-defined values.', 'A Josephson junction is formed by a superconducting wire, a small gap of a different material (insulator or normal metal), and another superconducting wire, which exhibits unusual current-voltage characteristics.']}, {'end': 947.818, 'segs': [{'end': 533.206, 'src': 'embed', 'start': 467.743, 'weight': 0, 'content': [{'end': 477.988, 'text': "um so, the speed of the pack is actually these fluxons, these these uh sort of pulses of of um current that are generated by joseph's injunctions.", 'start': 467.743, 'duration': 10.245}, {'end': 480.909, 'text': 'they can actually propagate very close to the speed of light.', 'start': 477.988, 'duration': 2.921}, {'end': 484.771, 'text': "uh, maybe something like a third of the speed of light, that's quite fast.", 'start': 480.909, 'duration': 3.862}, {'end': 493.436, 'text': "so one of the reasons why joseph's injunctions are appealing is because their signals can propagate quite fast, and they can.", 'start': 484.771, 'duration': 8.665}, {'end': 495.137, 'text': 'they can also switch very fast.', 'start': 493.436, 'duration': 1.701}, {'end': 505.667, 'text': 'What I mean by switch is perform that operation that I described where you add current to the loop that can happen within a few tens of picoseconds.', 'start': 495.157, 'duration': 10.51}, {'end': 510.489, 'text': 'So you can get you can get devices that operate in the hundreds of gigahertz range.', 'start': 505.727, 'duration': 4.762}, {'end': 518.89, 'text': 'And by comparison, most processors in our, in our conventional computers operate closer to the the one gigahertz range.', 'start': 510.609, 'duration': 8.281}, {'end': 524.253, 'text': 'maybe three gigahertz seems to be kind of where where those speeds have have leveled out.', 'start': 518.89, 'duration': 5.363}, {'end': 529.461, 'text': 'So the gamers listening to this are getting really excited that overclock their system to like.', 'start': 524.333, 'duration': 5.128}, {'end': 530.102, 'text': 'what is it like?', 'start': 529.461, 'duration': 0.641}, {'end': 533.206, 'text': 'four gigahertz or something 100 is sounds incredible.', 'start': 530.102, 'duration': 3.104}], 'summary': 'Josephson junctions can propagate signals close to the speed of light, switch within tens of picoseconds, and operate in the hundreds of gigahertz range, far surpassing conventional processors.', 'duration': 65.463, 'max_score': 467.743, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/2FdlMnAwi84/pics/2FdlMnAwi84467743.jpg'}, {'end': 638.61, 'src': 'embed', 'start': 613.01, 'weight': 3, 'content': [{'end': 619.172, 'text': "there's. there are physical limits that, no matter how good our technology got, those circuits would,", 'start': 613.01, 'duration': 6.162}, {'end': 625.634, 'text': 'i think would never be able to be scaled down to the the densities that silicon microelectronics can.', 'start': 619.172, 'duration': 6.462}, {'end': 627.435, 'text': "i don't know if we mentioned.", 'start': 625.634, 'duration': 1.801}, {'end': 632.497, 'text': 'is there something interesting about the various superconducting materials involved, or is it all?', 'start': 627.435, 'duration': 5.062}, {'end': 636.288, 'text': "there's a lot of stuff that's interesting and it's not silicon.", 'start': 632.825, 'duration': 3.463}, {'end': 638.61, 'text': "it's not silicon, no, so like.", 'start': 636.288, 'duration': 2.322}], 'summary': 'Physical limits restrict scaling down circuits like silicon microelectronics.', 'duration': 25.6, 'max_score': 613.01, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/2FdlMnAwi84/pics/2FdlMnAwi84613010.jpg'}, {'end': 680.84, 'src': 'embed', 'start': 653.722, 'weight': 4, 'content': [{'end': 657.545, 'text': 'Yeah, what kind of cooling system can achieve four Kelvin? Exactly, for Kelvin, you need liquid helium.', 'start': 653.722, 'duration': 3.823}, {'end': 661.628, 'text': "And so liquid helium is expensive, it's inconvenient.", 'start': 658.125, 'duration': 3.503}, {'end': 671.876, 'text': "You need a cryostat that sits there and the energy consumption of that cryostat impracticable, for it's not going in your cell phone, you're not?", 'start': 661.648, 'duration': 10.228}, {'end': 676.077, 'text': 'so you can picture holding your cell phone like this and then something the size of you know,', 'start': 671.876, 'duration': 4.201}, {'end': 680.84, 'text': 'a keg of beer or something on your back to cool it like that makes no sense.', 'start': 676.077, 'duration': 4.763}], 'summary': 'Cooling system achieving four kelvin requires liquid helium, which is expensive and impracticable for everyday use.', 'duration': 27.118, 'max_score': 653.722, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/2FdlMnAwi84/pics/2FdlMnAwi84653722.jpg'}, {'end': 776.793, 'src': 'embed', 'start': 749.942, 'weight': 5, 'content': [{'end': 756.226, 'text': "I don't think superconductors are going to replace semiconductors for digital computation.", 'start': 749.942, 'duration': 6.284}, {'end': 765.332, 'text': 'There are a lot of reasons for that, but I think ultimately what it comes down to is all things considered cooling errors,', 'start': 757.747, 'duration': 7.585}, {'end': 767.494, 'text': 'scaling down to feature sizes, all that stuff.', 'start': 765.332, 'duration': 2.162}, {'end': 770.711, 'text': 'semiconductors work better at the system level.', 'start': 767.89, 'duration': 2.821}, {'end': 776.793, 'text': 'Is there some aspect of just curious about the historical momentum of this??', 'start': 771.211, 'duration': 5.582}], 'summary': "Superconductors won't replace semiconductors for digital computation due to cooling errors and scaling issues.", 'duration': 26.851, 'max_score': 749.942, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/2FdlMnAwi84/pics/2FdlMnAwi84749942.jpg'}], 'start': 427.137, 'title': 'Speed and limitations of superconducting logic', 'summary': "Discusses the speed of current packets and josephson junction signals, enabling devices to operate in the hundreds of gigahertz range, surpassing conventional computer processors' speed. it also addresses the limitations of superconducting logic, including scaling challenges, temperature requirements, and impracticality in consumer electronics, ultimately favoring semiconductors at the system level.", 'chapters': [{'end': 533.206, 'start': 427.137, 'title': 'Speed of current and josephson junctions', 'summary': "Discusses the speed of current packets, with fluxons propagating close to the speed of light and josephson junction signals switching within a few tens of picoseconds, enabling devices to operate in the hundreds of gigahertz range, surpassing the conventional computer processors' speed of one to three gigahertz.", 'duration': 106.069, 'highlights': ["Fluxons can propagate very close to the speed of light, around a third of the speed of light. Fluxons, the discrete packets of current generated by Joseph's injunctions, can propagate at speeds nearing a third of the speed of light.", 'Josephson junction signals can switch within a few tens of picoseconds, enabling devices to operate in the hundreds of gigahertz range. Signals from Josephson junctions can perform switching operations within a few tens of picoseconds, allowing devices to operate at speeds in the hundreds of gigahertz range.', 'Most processors in conventional computers operate in the one to three gigahertz range, while gamers may overclock their systems to around four gigahertz. Conventional computer processors typically operate at speeds between one to three gigahertz, with gamers potentially overclocking their systems to around four gigahertz.']}, {'end': 947.818, 'start': 533.787, 'title': 'Superconducting logic and its limitations', 'summary': 'Discusses the limitations of superconducting logic, including the challenges of scaling down circuits, the necessity of super cold temperatures, and the impracticality of using superconductors in consumer electronics, ultimately concluding that semiconductors work better at the system level.', 'duration': 414.031, 'highlights': ['Superconducting circuits cannot be scaled down to the densities that silicon microelectronics can, due to fundamental physical reasons about the way the magnetic field interacts with superconducting material. Superconducting circuits cannot match the scaling capabilities of silicon microelectronics.', 'The necessity of super cold temperatures, such as requiring liquid helium at 4 Kelvin, makes the use of superconducting materials impractical for consumer electronics due to high cost, inconvenience, and energy consumption. The impracticality of using superconductors in consumer electronics due to the high cost, inconvenience, and energy consumption of super cold temperatures.', 'Semiconductors are ultimately more effective than superconductors at the system level for digital computation, due to factors such as cooling errors, scaling down to feature sizes, and overall system performance. Semiconductors are more effective than superconductors at the system level for digital computation.']}], 'duration': 520.681, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/2FdlMnAwi84/pics/2FdlMnAwi84427137.jpg', 'highlights': ['Fluxons can propagate very close to the speed of light, around a third of the speed of light.', 'Josephson junction signals can switch within a few tens of picoseconds, enabling devices to operate in the hundreds of gigahertz range.', 'Most processors in conventional computers operate in the one to three gigahertz range, while gamers may overclock their systems to around four gigahertz.', 'Superconducting circuits cannot be scaled down to the densities that silicon microelectronics can, due to fundamental physical reasons about the way the magnetic field interacts with superconducting material.', 'The necessity of super cold temperatures, such as requiring liquid helium at 4 Kelvin, makes the use of superconducting materials impractical for consumer electronics due to high cost, inconvenience, and energy consumption.', 'Semiconductors are ultimately more effective than superconductors at the system level for digital computation, due to factors such as cooling errors, scaling down to feature sizes, and overall system performance.']}], 'highlights': ['Superconductivity in semiconductors allows for induced currents to flow indefinitely at low temperatures, with no dissipation, in contrast to typical semiconductor behavior.', 'Conventional superconductors operate at around four Kelvin, allowing electrons to settle into a macroscopic quantum state.', 'Josephson junctions serve as gates and can perform logic operations analogous to transistors.', 'Fluxons can propagate very close to the speed of light, around a third of the speed of light.', 'Josephson junction signals can switch within a few tens of picoseconds, enabling devices to operate in the hundreds of gigahertz range.', 'The necessity of super cold temperatures, such as requiring liquid helium at 4 Kelvin, makes the use of superconducting materials impractical for consumer electronics due to high cost, inconvenience, and energy consumption.']}