WEBVTT - What is a Quantum Computer? 0:00:01.639 --> 0:00:05.240 Hey, welcome to Sign Stuff, a production of iHeartRadio. My 0:00:05.320 --> 0:00:07.200 name is Jorge cham and to the end of the program, 0:00:07.280 --> 0:00:10.959 we are talking about a technology that may potentially impact 0:00:11.039 --> 0:00:14.760 the life of every single human on Earth. It might 0:00:14.840 --> 0:00:17.360 change how we protect data and come up with passwords, 0:00:17.480 --> 0:00:20.079 it might help us make new and exciting materials, and 0:00:20.160 --> 0:00:25.560 it might render cryptocurrencies like bitcoin and dotgecoin totally useless. 0:00:26.040 --> 0:00:30.120 I'm talking about quantum computers. What are they, how do 0:00:30.200 --> 0:00:32.559 they work? And most exciting is that we're going to 0:00:32.560 --> 0:00:35.320 get to visit one of them and actually hear it 0:00:35.400 --> 0:00:39.479 in action. So power up your curiosity, log in, and 0:00:39.560 --> 0:00:48.200 let's answer the question how do quantum computers work? Hey? Everyone? Okay, 0:00:48.400 --> 0:00:51.360 so when I started this episode, I was both terrified 0:00:51.560 --> 0:00:55.800 and excited. Terrified because explaining anything with the word quantum 0:00:56.080 --> 0:00:58.960 is really hard, but excited because I had heard that 0:00:59.040 --> 0:01:02.720 a friend of mine was making quantum computers just ten 0:01:02.760 --> 0:01:05.280 minutes from my house, and this was a great excuse 0:01:05.319 --> 0:01:07.240 for me to go take a look at them. So 0:01:07.280 --> 0:01:09.920 we're going to go see these quantum computers in person 0:01:10.200 --> 0:01:12.399 at the end of the episode, but before that, I 0:01:12.400 --> 0:01:14.840 wanted to make sure that I understood what they were 0:01:15.160 --> 0:01:18.280 how they work, and also what they're potentially going to 0:01:18.319 --> 0:01:22.120 be used for. So this episode is split into three parts. 0:01:22.400 --> 0:01:24.679 What is a quantum computer and how does it work? 0:01:25.120 --> 0:01:27.959 What are quantum computers for? And then we're going to 0:01:28.000 --> 0:01:30.240 go see the quantum computers and we're going to talk 0:01:30.240 --> 0:01:32.880 about how they're made and why they're so hard to 0:01:32.920 --> 0:01:35.080 get them to work. Our guide through all of this 0:01:35.280 --> 0:01:37.880 is going to be my friend who's making the quantum computers, 0:01:38.080 --> 0:01:41.559 Professor Oscar Pater. He's a professor of physics and applied 0:01:41.560 --> 0:01:44.960 physics at Caltech and he's the head of quantum hardware 0:01:45.280 --> 0:01:49.680 for Amazon. He does research on nanophotonics, quantum optics, and 0:01:49.760 --> 0:01:54.520 of course quantum computers. Here's my visit to Oscar Painter's lab. 0:02:00.240 --> 0:02:03.000 Ah, hey, Oscar, how are you good to see you 0:02:03.040 --> 0:02:04.040 after so many years. 0:02:04.120 --> 0:02:06.400 Yeah, it's been a while. Huh yeah, well thanks so 0:02:06.480 --> 0:02:07.320 much for talking with me. 0:02:07.480 --> 0:02:10.240 Yeah, it's been a while. Happy to try to fill 0:02:10.280 --> 0:02:11.919 you in on some of the things we've been doing 0:02:11.919 --> 0:02:13.080 in the areas of quantic computing. 0:02:13.880 --> 0:02:15.519 Okay, so the first thing I wanted to talk to 0:02:15.600 --> 0:02:19.200 him about was just what does the word quantum mean? 0:02:19.560 --> 0:02:21.360 Because I feel like we're going to need that to 0:02:21.520 --> 0:02:26.080 understand what a quantum computer is. Now, the word quantum 0:02:26.280 --> 0:02:29.080 is the word we used to describe how things behave 0:02:29.240 --> 0:02:32.200 at the level of atoms and the tiny little particles 0:02:32.240 --> 0:02:35.000 that make up the atoms. So in our everyday lives, 0:02:35.080 --> 0:02:37.800 we're used to things being solid and us being able 0:02:37.840 --> 0:02:39.880 to hold them, like, for example, if you take a 0:02:39.880 --> 0:02:42.240 piece of wood or a ball. But if you take 0:02:42.240 --> 0:02:44.480 that piece of wood or ball and you chop it up, 0:02:44.520 --> 0:02:47.240 and you keep chopping it up, you get down to atoms, 0:02:47.280 --> 0:02:50.120 and then you'll notice that those atoms don't behave in 0:02:50.160 --> 0:02:52.280 the same way that a piece of wood or a 0:02:52.280 --> 0:02:55.679 ball do. Here's how Oscar explains it. 0:02:55.680 --> 0:02:58.640 It turns out that down to the microscopic scale, so 0:02:58.720 --> 0:03:01.399 not our everyday scale of things, the laws of physics 0:03:01.400 --> 0:03:04.600 that dominate in that regime is quantum mechanics, and quantum 0:03:04.600 --> 0:03:07.960 mechanics is a theory that has some strange attributes that 0:03:08.000 --> 0:03:11.600 we don't experience every day. For example, it postulates that 0:03:11.840 --> 0:03:15.480 things can be in superposition, so you can have objects 0:03:15.520 --> 0:03:17.280 being in sort of what we think of as two 0:03:17.280 --> 0:03:20.400 distinct realities at the same time. Imagine having a particle 0:03:20.400 --> 0:03:24.360 in one position and another position simultaneously. That seems very 0:03:24.360 --> 0:03:27.200 odd to us, but in quantum mechanics it's very natural. 0:03:28.080 --> 0:03:30.440 Like, for example, I grabbed this piece of wood in 0:03:30.440 --> 0:03:32.160 front of me, and it's a piece of wood. It's 0:03:32.160 --> 0:03:34.560 not two things at the same time. Right, It's in 0:03:34.600 --> 0:03:35.200 one location. 0:03:35.480 --> 0:03:37.440 Right, it's sitting there. It's firmly right in front of you. 0:03:37.760 --> 0:03:39.280 Right. If I had an atom in front of me 0:03:39.400 --> 0:03:42.520 or an electron, it wouldn't exactly. 0:03:42.520 --> 0:03:44.760 You would find that if you repeated the measurement or 0:03:44.800 --> 0:03:47.960 finding its position multiple times, you might find that, Oh, 0:03:48.000 --> 0:03:50.720 I get this weird outcome that sometimes I measure it here, 0:03:50.760 --> 0:03:53.280 sometimes I measure it there. And that's because it's actually 0:03:53.320 --> 0:03:56.320 in many places at once, all right, And that's fundamental 0:03:56.360 --> 0:03:58.960 to the description of quantum mechanics. The way I like 0:03:58.960 --> 0:04:02.920 to think about quantum mechanics is really as waves and amplitudes. 0:04:03.080 --> 0:04:05.480 So think about you're at a pond and you throw 0:04:05.480 --> 0:04:07.200 a rock in a pond, and you see this ripple 0:04:07.280 --> 0:04:09.840 of the rock. Right, That's how I think about, Like 0:04:09.880 --> 0:04:12.640 the rocks are sort of the particles, and these wave 0:04:12.640 --> 0:04:16.360 phenomena are sort of the actual physical quantum mechanical description 0:04:16.520 --> 0:04:17.400 of that particle. 0:04:18.000 --> 0:04:21.240 Like the particle the thing, the atom or the electron. 0:04:21.400 --> 0:04:23.480 It's not the rock you throw into the pond, no, 0:04:23.520 --> 0:04:25.320 but it's actually the ripple of the ripple. 0:04:25.400 --> 0:04:28.039 Yeah, that's right, it's this wave. So I may have 0:04:28.040 --> 0:04:30.040 started with something that was very local, like that rock, 0:04:30.400 --> 0:04:33.000 but then it becomes very quickly it sort of propagates 0:04:33.000 --> 0:04:35.279 out and is actually better described as this wave on 0:04:35.320 --> 0:04:36.200 the pond. 0:04:36.400 --> 0:04:38.240 Because like a ripple and a wave in a pond 0:04:38.279 --> 0:04:40.320 like that, it's kind of in a lot of places 0:04:40.320 --> 0:04:40.880 at the same. 0:04:40.680 --> 0:04:44.600 Exactly, that's right. And then the interference is important to understand. 0:04:44.640 --> 0:04:46.800 If I throw two rocks in the pond, then I 0:04:46.839 --> 0:04:49.479 see the sort of interference of the ripple patterns coming 0:04:49.480 --> 0:04:51.680 from each rock that blashed in the pond. 0:04:51.480 --> 0:04:54.600 Right, Like each ripple starts at simple, but then they 0:04:54.680 --> 0:04:58.039 start to mix together and form this complex pattern on 0:04:58.080 --> 0:04:59.640 the surface of the pod. 0:05:00.120 --> 0:05:02.839 Exactly, like how do they evolve in time? 0:05:03.880 --> 0:05:06.680 Okay, so when you get down to the level of atoms, 0:05:06.960 --> 0:05:10.880 things behave really strangely. Scientists think of things at that 0:05:11.000 --> 0:05:14.840 level not as little tiny balls, but as waves or 0:05:15.040 --> 0:05:18.120 ripples of energy, like the ripples in a pond. Now 0:05:18.160 --> 0:05:20.240 you may think, wait a minute, if things are kind 0:05:20.240 --> 0:05:23.599 of wavy and strange at the level of atoms. Why 0:05:23.640 --> 0:05:25.640 isn't it that way when you get to big stuff 0:05:25.680 --> 0:05:28.000 like a piece of wood or a ball, And the 0:05:28.120 --> 0:05:31.159 answer is that they are that way. There's just a 0:05:31.279 --> 0:05:34.000 lot of atoms in a piece of wood, and from 0:05:34.040 --> 0:05:37.040 a distance, it gives you the impression that it's solid. 0:05:38.000 --> 0:05:40.880 It's sort of like how some clouds from afar they 0:05:41.040 --> 0:05:43.400 might look solid once you get up close to them, 0:05:43.480 --> 0:05:46.280 they're actually kind of fuzzy and wispy, and all the 0:05:46.320 --> 0:05:49.960 water droplets are moving around. So that's quantum. Now. A 0:05:50.040 --> 0:05:53.680 quantum computer is what happens when you make a regular computer, 0:05:54.200 --> 0:05:57.640 but you make the circuits out of individual atoms or 0:05:57.680 --> 0:05:59.400 particles like electrons. 0:06:00.880 --> 0:06:03.640 Classical computers are formed from things that are very very 0:06:03.640 --> 0:06:04.839 classical in nature. 0:06:04.680 --> 0:06:06.880 And they uperate kind of on hard switches. 0:06:07.080 --> 0:06:09.520 Yeah, like, yeah, that's right, the transistors on your phone, 0:06:09.560 --> 0:06:11.240 And that's what we call these types of elements. The 0:06:11.279 --> 0:06:15.200 transistors are used to store information or perform calculations, and 0:06:15.240 --> 0:06:17.880 the transistors are really set by a bunch of electrons 0:06:18.080 --> 0:06:20.159 in part of the circuit. And usually you're talking about 0:06:20.279 --> 0:06:22.400 quite a few electrons. 0:06:21.960 --> 0:06:25.760 Because regular transistors are huge. They're bigger than an atom. 0:06:25.880 --> 0:06:28.440 Yes, exactly, that's physically what's going on in your phone. 0:06:28.520 --> 0:06:30.680 And what I'm telling you is that the way to 0:06:30.680 --> 0:06:32.960 think about it is in the quantum case, I just 0:06:33.040 --> 0:06:34.200 have one electron. 0:06:34.120 --> 0:06:37.000 Like the circuits are made out of individual electrons. 0:06:37.240 --> 0:06:39.520 Yeah, atoms is exactly what you're doing. Or a quantum 0:06:39.520 --> 0:06:41.880 particle doesn't have to be electrons, can be other particles. 0:06:41.920 --> 0:06:44.440 That was the sort of very early idea from people 0:06:44.440 --> 0:06:46.920 like FIM and others back in the nineteen eighties is 0:06:47.000 --> 0:06:50.159 if you're going to do this, and you better make 0:06:50.240 --> 0:06:52.440 them out of quantum mechanical objects to begin with. 0:06:53.279 --> 0:06:56.120 Okay, So if you make a computer where the circuits 0:06:56.160 --> 0:07:00.640 are made of individual quantum objects like atoms or electrons, 0:07:00.839 --> 0:07:03.520 then you get a quantum computer. And what that does 0:07:03.720 --> 0:07:08.080 is that it makes their calculations also quantum mechanical. And 0:07:08.160 --> 0:07:10.760 this is where the concept of a cubit comes in. 0:07:11.040 --> 0:07:13.840 It's like a regular bit in your computer, and a 0:07:13.840 --> 0:07:16.440 bit is like a one or zero, but a cubit 0:07:16.520 --> 0:07:19.280 is a quantum mechanical one or zero. 0:07:20.880 --> 0:07:23.800 Classical computers are formed from digital bits and they go 0:07:23.960 --> 0:07:28.080 between one and zero. A quantum computer doesn't have these 0:07:28.480 --> 0:07:32.000 hard zero one states. It has every possibility in between. 0:07:32.240 --> 0:07:34.840 So imagine if we have these two states zero in one. 0:07:35.600 --> 0:07:37.440 I told you that a quantum system can be in 0:07:37.520 --> 0:07:40.000 two different states at once, right, So it can be 0:07:40.000 --> 0:07:42.360 in zero and one at the same time, and I 0:07:42.440 --> 0:07:44.720 can have a different weight of zero or one at 0:07:44.720 --> 0:07:46.760 the same time. It could be ten percent zero, ninety 0:07:46.800 --> 0:07:47.280 percent one. 0:07:48.000 --> 0:07:49.280 It's like a shade of gray. 0:07:49.520 --> 0:07:52.720 Yeah, And so you have all those possibilities in between. 0:07:52.800 --> 0:07:55.560 It can be zero or one or anything in between. 0:07:55.960 --> 0:07:58.480 It can be black, white, dark, gray, light. 0:07:58.400 --> 0:08:00.560 Gray, exactly, So it has all those shape in between. 0:08:00.680 --> 0:08:03.120 You can take zero with some fraction and add it 0:08:03.160 --> 0:08:05.600 to one with any other fraction. You can have any 0:08:05.680 --> 0:08:06.440 combination of that. 0:08:07.320 --> 0:08:10.800 So on a regular computer, if you multiply two bits together, 0:08:11.000 --> 0:08:14.760 it's like you're multiplying two fixed numbers together, like three 0:08:14.880 --> 0:08:18.080 times four. But in a quantum computer, when you multiply 0:08:18.160 --> 0:08:21.680 two cubits together, it's like you're multiplying two things that 0:08:21.800 --> 0:08:24.720 can be lots of numbers at the same time. So, 0:08:24.800 --> 0:08:28.160 for example, it's like you're multiplying every number from zero 0:08:28.240 --> 0:08:31.920 to one hundred times every number from zero to one thousand, 0:08:32.240 --> 0:08:36.160 all at the same time in one operation. That's what 0:08:36.240 --> 0:08:39.520 makes quantum computers unique. They take this weirdness of the 0:08:39.640 --> 0:08:43.040 quantum world and then let's you do math with it. Now, Actually, 0:08:43.080 --> 0:08:46.120 it's not doing all of those multiplications or calculations at 0:08:46.120 --> 0:08:49.560 the same time. It's more like how Oscar described it earlier. 0:08:49.840 --> 0:08:52.200 If you drop two rocks in a pond, you see 0:08:52.240 --> 0:08:55.600 the two ripples spread out and mix together to form 0:08:55.679 --> 0:08:59.120 a complex ripple pattern. That's more of the picture of 0:08:59.120 --> 0:09:02.320 what a quantum comp does. It doesn't do calculations with 0:09:02.440 --> 0:09:06.360 hard numbers. It does calculations with the ripples and patterns 0:09:06.400 --> 0:09:10.600 of quantum numbers. Of course, my next question for Oscar 0:09:10.840 --> 0:09:13.600 was what is that good for? Why would you want 0:09:13.640 --> 0:09:16.880 to do math this way? When we come back, I'm 0:09:16.920 --> 0:09:20.240 going to ask Oscar what quantum computers are for, and 0:09:20.280 --> 0:09:22.360 then at the end we're going to go check out 0:09:22.480 --> 0:09:35.160 the ones he's built. You're listening to sign stuff. Welcome back. Okay, 0:09:35.480 --> 0:09:38.000 to recap, we learned that a quantum computer is a 0:09:38.040 --> 0:09:42.320 regular computer whose circuits are made with individual atoms or 0:09:42.320 --> 0:09:45.719 small particles like electrons, and by doing that you can 0:09:45.760 --> 0:09:49.560 do quantum calculations. That is, you can do math, but 0:09:49.640 --> 0:09:52.959 with numbers that are actually lots of different numbers at 0:09:52.960 --> 0:09:55.440 the same time. So now the question is, why would 0:09:55.440 --> 0:09:58.040 you want to do that? What are quantum computers? Four? 0:09:58.520 --> 0:10:02.280 Here's more of my conversation, but quantum physicist Oscar Painter. 0:10:03.640 --> 0:10:05.600 Let's say it's a few years into the future and 0:10:05.640 --> 0:10:08.680 we have quantum computers, yes, in our phones, like I 0:10:08.679 --> 0:10:11.040 have one in my podget Okay, what can I do 0:10:11.080 --> 0:10:12.480 with it? And how is my life different? 0:10:13.840 --> 0:10:15.680 I think that's a very unlikely scenario. 0:10:16.880 --> 0:10:17.320 Okay. 0:10:17.760 --> 0:10:19.440 I think that's the wrong way. 0:10:19.360 --> 0:10:22.480 To think about how quantic computers might change our lives, 0:10:23.600 --> 0:10:26.560 at least as far as I can project into the future. Okay, 0:10:26.880 --> 0:10:28.960 I think the best way to think about a quantic 0:10:29.000 --> 0:10:32.240 computer as we envision it right now is that it 0:10:32.280 --> 0:10:33.400 will be more. 0:10:33.240 --> 0:10:34.640 Like a supercomputer. 0:10:34.920 --> 0:10:37.880 So a supercomputer is just a very large computer that 0:10:38.000 --> 0:10:42.280 can perform calculations beyond what our desktop, our personal computers 0:10:42.320 --> 0:10:45.400 can do. And these are usually very large, almost building 0:10:45.440 --> 0:10:49.319 scale computers and computer clusters that have many, many different 0:10:49.320 --> 0:10:51.839 processing units that are all integrated together, and through that 0:10:51.920 --> 0:10:55.440 scale you can perform a huge number of computations per 0:10:55.480 --> 0:10:58.360 second and therefore compute some of the hardest problems. 0:10:58.000 --> 0:10:58.520 That are out there. 0:10:58.600 --> 0:11:01.360 A lot of them are used for chemistry problems. They're 0:11:01.440 --> 0:11:05.160 used to study particle physics, so fundamental physics, trying to 0:11:05.360 --> 0:11:08.559 understand models of quantum particles that are beyond the current 0:11:08.559 --> 0:11:12.680 standard model. They're used to compute the properties of materials, 0:11:12.920 --> 0:11:14.360 climate modeling, and things like that. 0:11:14.600 --> 0:11:17.120 So usually science and tech, yeahs, And. 0:11:17.120 --> 0:11:19.840 There's always this competition between different nations who has the 0:11:20.000 --> 0:11:22.120 fastest or the biggest supercomputer. 0:11:22.679 --> 0:11:26.240 I see, So you envision quantum computers will be sort 0:11:26.240 --> 0:11:28.360 of like a specialized version of computer. 0:11:28.480 --> 0:11:31.040 It's going to be some very special type of supercomputer 0:11:31.240 --> 0:11:34.360 that can solve specific problems that quantum computers will be 0:11:34.440 --> 0:11:37.600 very effective at that we can't do today on classic computers, 0:11:37.640 --> 0:11:39.640 no matter how much we scale them up. And the 0:11:39.720 --> 0:11:43.319 key is it's not just a faster supercomputer. It performs 0:11:43.360 --> 0:11:46.640 calculations in a fundamentally different way, and therefore it can 0:11:46.679 --> 0:11:49.680 tackle problems that are possibly outside of the reach of 0:11:49.720 --> 0:11:52.120 these conventional classical supercomputers. 0:11:52.440 --> 0:11:54.640 What do you mean? Out of the reach meaning that. 0:11:54.640 --> 0:11:56.760 No matter how fast they get or how big they get, 0:11:56.800 --> 0:11:59.080 they'll never be able to compute some of these problems, 0:11:59.440 --> 0:12:03.319 never or take an infinite exactly, it's just the scaling 0:12:03.400 --> 0:12:06.200 is so bad for these problems, you would take way 0:12:06.240 --> 0:12:10.040 too long and require way too large on machine. So, 0:12:10.080 --> 0:12:13.480 no matter how hard we work on our current computing technology, 0:12:13.880 --> 0:12:16.360 it has limits and it's known and you can prove 0:12:16.360 --> 0:12:20.160 it for certain problems, and quantic computers when they looked 0:12:20.160 --> 0:12:24.800 at theoretically these same problems, they realize that the same 0:12:25.040 --> 0:12:29.240 restrictions or limitations for quantic computers are not there. There's 0:12:29.360 --> 0:12:34.040 examples where we believe and strongly believe that certain mathematical 0:12:34.080 --> 0:12:37.880 problems that are important are really really hard to perform 0:12:38.120 --> 0:12:41.200 and can't be solved using classical means, no matter how 0:12:41.520 --> 0:12:42.720 much we improve the technology. 0:12:42.960 --> 0:12:45.000 No matter if I have a building full of supercomputers, 0:12:45.040 --> 0:12:46.560 yeah exactly, you'll never be able. 0:12:46.400 --> 0:12:48.320 To just fill the world with them. You still won't 0:12:48.360 --> 0:12:51.120 be able to do it. Yet a quantic computer can 0:12:51.160 --> 0:12:52.440 solve it pretty efficiently. 0:12:53.480 --> 0:12:55.640 Well. Step me through some of these problems. 0:12:55.679 --> 0:12:58.560 Like so the example that everyone points to, and it 0:12:58.640 --> 0:13:03.679 is pretty amazing that people found this, But there's this 0:13:03.800 --> 0:13:06.720 mathematical problem. It just happens to be very applicable to 0:13:06.800 --> 0:13:09.400 our safety or security of our data. So it turns 0:13:09.400 --> 0:13:11.959 out that most of the security of all of the 0:13:12.040 --> 0:13:14.920 data that you hold, all the data that banks or 0:13:15.000 --> 0:13:18.080 various institutions around the world want to be safe and protected, 0:13:18.120 --> 0:13:21.319 they typically encrypt it. And those encryption techniques that have 0:13:21.400 --> 0:13:25.280 been used were what are called RSA encryption, where you 0:13:25.360 --> 0:13:27.960 want to take a large number and understand what its 0:13:28.040 --> 0:13:28.880 prime factors are. 0:13:29.840 --> 0:13:32.920 Okay, so the first big thing that quantum computers can 0:13:32.960 --> 0:13:35.720 be useful, the one that got people really excited about 0:13:35.720 --> 0:13:40.360 them in the nineties, is in breaking password encryption. So 0:13:40.520 --> 0:13:43.400 whenever you enter your password on a website or when 0:13:43.400 --> 0:13:47.400 you download your bank statement, that information is encrypted or 0:13:47.440 --> 0:13:51.160 scrambled so that if anyone happens to catch that information, 0:13:51.559 --> 0:13:54.800 they can't tell what it says. And the whole scheme 0:13:55.120 --> 0:13:57.240 is based on the idea that if I gave you 0:13:57.280 --> 0:14:00.600 a really large number, it's really hard to find what 0:14:00.640 --> 0:14:04.640 its prime factors are. Here's how Oscar explains it, but 0:14:04.800 --> 0:14:06.720 just to give you a quick heads up, a prime 0:14:06.800 --> 0:14:09.800 number is a number that can't be divided except by 0:14:09.840 --> 0:14:14.000 itself or by one. So, for example, thirteen is a 0:14:14.000 --> 0:14:17.520 prime number because you can't fight thirteen by anything except 0:14:17.679 --> 0:14:22.360 thirteen and one, And the same goes for seventeen nineteen 0:14:22.600 --> 0:14:26.640 twenty three and so on. Anyways, here's Oscar explaining it. 0:14:27.400 --> 0:14:29.200 So I give you a number and I say, tell 0:14:29.200 --> 0:14:31.600 me what the prime factors are, and you have to 0:14:31.600 --> 0:14:34.600 break it down to its prime factors. So you know, 0:14:34.640 --> 0:14:36.400 a simple one is, you know, like two, it's just 0:14:36.480 --> 0:14:37.920 one times two, one and two. Those are the two 0:14:37.960 --> 0:14:40.240 prime factors, right. But it gets harder as these numbers 0:14:40.280 --> 0:14:40.800 get bigger. 0:14:41.000 --> 0:14:42.880 If I tell you one millions be round there and 0:14:43.000 --> 0:14:44.560 forty three. 0:14:44.040 --> 0:14:50.320 Yeah, seventeen, very hard to actually answer what those what 0:14:50.360 --> 0:14:52.160 the prime factors are. But if I give you the 0:14:52.160 --> 0:14:54.480 prime factors, you can multiply them together and very quickly 0:14:54.520 --> 0:14:56.400 get the answer to what that larger number is. 0:14:56.520 --> 0:14:56.680 Right. 0:14:57.440 --> 0:14:59.280 And so if you know the prime factors, I can 0:14:59.320 --> 0:15:00.600 give you what they multiply to. 0:15:00.920 --> 0:15:01.640 But if you give me. 0:15:01.600 --> 0:15:04.240 The number that they multiply to without then I have 0:15:04.280 --> 0:15:06.640 a very hard time finding out what the prime factors are. 0:15:06.600 --> 0:15:08.720 Because you'd have to get kind of have to guess. 0:15:09.000 --> 0:15:12.520 Well, you know, there's mathematical techniques to try to find these, 0:15:12.520 --> 0:15:13.560 but they're very inefficient. 0:15:14.840 --> 0:15:16.040 And so it turns. 0:15:15.800 --> 0:15:18.560 Out that most of the security of the way we 0:15:18.720 --> 0:15:22.560 encrypt information is based upon that asymmetry. And how hard 0:15:22.560 --> 0:15:23.120 the problem is. 0:15:23.640 --> 0:15:25.880 So, now, let's say somebody has a quantum computer. 0:15:25.760 --> 0:15:29.880 Right, then they can find those prime factors and they 0:15:29.880 --> 0:15:31.520 can now decrypt all that information. 0:15:32.200 --> 0:15:34.800 They can just grab it from the air, yeah, and 0:15:34.840 --> 0:15:35.600 be like, oh, I know. 0:15:35.720 --> 0:15:38.440 And yeah, I can find the prime factors and then 0:15:38.480 --> 0:15:41.600 I can use that to decrypt the information. 0:15:42.000 --> 0:15:43.760 That would be easy for a quantum computer, and you 0:15:43.800 --> 0:15:45.600 just press a button and will tell you, oh, this 0:15:45.760 --> 0:15:48.400 is an oscar or his secret decoder. 0:15:48.600 --> 0:15:53.720 Yeah, exactly, So that would you know. That obviously concerned 0:15:54.000 --> 0:15:57.000 a lot of people when that algorithm was developed. 0:15:58.480 --> 0:16:01.120 Okay, this gets a little bit heavy into encryption and 0:16:01.320 --> 0:16:04.320 quantum algorithms, but the main point is that most of 0:16:04.360 --> 0:16:08.240 the security of our passwords and our sensitive information, and 0:16:08.280 --> 0:16:11.800 also the encryption of things like bitcoin and all those cryptocurrencies, 0:16:12.000 --> 0:16:15.800 they all depend on this one math problem which is 0:16:15.920 --> 0:16:20.000 really hard for regular computers even supercomputers to solve. And 0:16:20.040 --> 0:16:23.400 that is a problem of finding the two prime numbers 0:16:23.440 --> 0:16:27.000 that multiply to get a really large number. But then 0:16:27.040 --> 0:16:30.000 in nineteen ninety five, a computer scientist named Peter Shore 0:16:30.120 --> 0:16:34.240 publish the paper titled Polynomial time Algorithms for prime factorization 0:16:34.280 --> 0:16:37.720 of discrete logarithms. On a quantum computer, which essentially showed 0:16:37.720 --> 0:16:40.200 that if you have a quantum computer, you can solve 0:16:40.200 --> 0:16:42.880 this problem in a short amount of time. And this 0:16:42.960 --> 0:16:45.480 is probably the main reason that people have been rushing 0:16:45.480 --> 0:16:49.240 to make quantum computers since then, because imagine if everyone 0:16:49.280 --> 0:16:53.360 in the world, people, companies, countries are all protecting their 0:16:53.440 --> 0:16:56.440 secrets using the same trick, but you had a special 0:16:56.520 --> 0:16:59.840 quantum computer that could break that trick, you could rule 0:16:59.880 --> 0:17:03.520 the world. Now, the details of how Peter Shore's algorithm 0:17:03.600 --> 0:17:06.119 works are a little complicated to explain here, but the 0:17:06.240 --> 0:17:08.840 essence of it is that you're using the ripples on 0:17:08.920 --> 0:17:12.320 a pawn nature of quantum numbers on a quantum computer 0:17:12.560 --> 0:17:16.560 to basically try out every possible combination for how to 0:17:16.600 --> 0:17:19.840 break your secret encryption, and you use some clever math 0:17:19.920 --> 0:17:23.639 tricks so that these ripples combine and mix together until 0:17:23.680 --> 0:17:26.840 the right answer pops out. So that is the main 0:17:26.880 --> 0:17:30.280 reason that people are excited about quantum computers. But there 0:17:30.320 --> 0:17:34.760 are other reasons and other possible applications, So here's Oscar 0:17:34.920 --> 0:17:36.879 telling me about them. 0:17:37.520 --> 0:17:40.560 Another example is maybe more natural to think about, and 0:17:40.600 --> 0:17:42.600 this is where quantum computers were first proposed. It to 0:17:42.680 --> 0:17:46.080 be interesting or useful, and that is the simulation of 0:17:46.520 --> 0:17:51.040 nature itself. Nature as we know it is not classical. 0:17:51.160 --> 0:17:54.040 If you peel the layers of the onion enough and 0:17:54.080 --> 0:17:56.399 you get down to the core, right to the atomic scale, 0:17:56.400 --> 0:17:59.199 it turns out that the laws of physics that dominates 0:17:59.280 --> 0:18:03.640 quantum mechanics, okay, like the actual mathematics of that, when 0:18:03.640 --> 0:18:06.800 you describe it, when you have many particles, it quickly 0:18:06.840 --> 0:18:09.760 becomes something that you can't simulate with a classical computer. 0:18:10.040 --> 0:18:12.920 So all those interference of all the particles and keeping 0:18:12.960 --> 0:18:14.840 track of all of that. A classical computer, if you 0:18:14.880 --> 0:18:17.240 try to simulate that, you quickly run out of steam 0:18:18.200 --> 0:18:21.840 and it becomes an exponentially hard problem. And so you know, 0:18:21.880 --> 0:18:23.639 a classical computer is just ill suited. 0:18:23.400 --> 0:18:23.840 To doing that. 0:18:24.280 --> 0:18:26.360 But a quantum computer that's made out of the same 0:18:26.480 --> 0:18:29.080 those sort of particles that can do with that interference naturally, 0:18:29.320 --> 0:18:31.520 you know, has a natural advantage in terms of using 0:18:31.560 --> 0:18:34.600 it to simulate the natural world at its quantum mechanical core. 0:18:35.119 --> 0:18:36.080 Why would I want to do that? 0:18:36.440 --> 0:18:38.720 Yeah, So that's the questions like, okay, so that's great, 0:18:38.880 --> 0:18:40.239 but why would I want to do that other than 0:18:40.280 --> 0:18:43.800 maybe I want to understand physics better? Well, this idea 0:18:43.840 --> 0:18:46.240 that I want to understand how material behaves is a 0:18:46.320 --> 0:18:48.679 very good example. If I'm building an electrical circuit, or 0:18:48.720 --> 0:18:52.439 I'm building a new battery, or I'm building a different 0:18:52.600 --> 0:18:55.560 energy process inside of a material or energy storage device. 0:18:55.880 --> 0:18:57.640 A lot of times that depends on what the electrons 0:18:57.640 --> 0:19:01.200 are doing. If I want to understand or something unique 0:19:01.200 --> 0:19:03.920 when I describe them quantum mechanically, maybe there's special properties 0:19:03.920 --> 0:19:06.560 I'm just totally blind to. So if I wanted to 0:19:06.560 --> 0:19:10.320 make a better superconnecting material, something that can carry electricity 0:19:10.400 --> 0:19:15.040 with no resistance, right, maybe we can have magnetically livitated trains. 0:19:15.080 --> 0:19:18.240 Maybe you can have you know, really efficient electrical circuits 0:19:18.240 --> 0:19:19.600 that don't dissipate any energy. 0:19:19.800 --> 0:19:20.600 All of these things. 0:19:20.680 --> 0:19:22.320 Then I would have to use a quantum computer to 0:19:22.359 --> 0:19:23.240 model that behavior. 0:19:23.840 --> 0:19:26.520 And you said there's some maybe potential applications in chemistry 0:19:26.560 --> 0:19:27.160 and biology. 0:19:27.280 --> 0:19:29.120 Yeah, you know, if I think about what is going 0:19:29.160 --> 0:19:32.520 on when I have a chemical reaction, usually it comes 0:19:32.520 --> 0:19:34.680 down to the electrons, and I need to understand what 0:19:34.720 --> 0:19:37.040 they're doing in order to understand, you know, whether this 0:19:37.119 --> 0:19:39.879 chemical reaction is going to be efficient or not, or 0:19:40.000 --> 0:19:42.159