Hey, welcome to Sign Stuff, a production of iHeartRadio. My name is Jorge cham and to the end of the program, we are talking about a technology that may potentially impact the life of every single human on Earth. It might change how we protect data and come up with passwords, it might help us make new and exciting materials, and it might render cryptocurrencies like bitcoin and dotgecoin totally useless. I'm talking about quantum computers. What are they, how do they work? And most exciting is that we're going to get to visit one of them and actually hear it in action. So power up your curiosity, log in, and let's answer the question how do quantum computers work? Hey? Everyone? Okay, so when I started this episode, I was both terrified and excited. Terrified because explaining anything with the word quantum is really hard, but excited because I had heard that a friend of mine was making quantum computers just ten minutes from my house, and this was a great excuse for me to go take a look at them. So we're going to go see these quantum computers in person at the end of the episode, but before that, I wanted to make sure that I understood what they were how they work, and also what they're potentially going to be used for. So this episode is split into three parts. What is a quantum computer and how does it work? What are quantum computers for? And then we're going to go see the quantum computers and we're going to talk about how they're made and why they're so hard to get them to work. Our guide through all of this is going to be my friend who's making the quantum computers, Professor Oscar Pater. He's a professor of physics and applied physics at Caltech and he's the head of quantum hardware for Amazon. He does research on nanophotonics, quantum optics, and of course quantum computers. Here's my visit to Oscar Painter's lab.

Hey, welcome to Sign Stuff, a production of iHeartRadio. My name is Jorge cham and to the end of the program, we are talking about a technology that may potentially impact the life of every single human on Earth. It might change how we protect data and come up with passwords, it might help us make new and exciting materials, and it might render cryptocurrencies like bitcoin and dotgecoin totally useless. I'm talking about quantum computers. What are they, how do they work? And most exciting is that we're going to get to visit one of them and actually hear it in action. So power up your curiosity, log in, and let's answer the question how do quantum computers work? Hey? Everyone? Okay, so when I started this episode, I was both terrified and excited. Terrified because explaining anything with the word quantum is really hard, but excited because I had heard that a friend of mine was making quantum computers just ten minutes from my house, and this was a great excuse for me to go take a look at them. So we're going to go see these quantum computers in person at the end of the episode, but before that, I wanted to make sure that I understood what they were how they work, and also what they're potentially going to be used for. So this episode is split into three parts. What is a quantum computer and how does it work? What are quantum computers for? And then we're going to go see the quantum computers and we're going to talk about how they're made and why they're so hard to get them to work. Our guide through all of this is going to be my friend who's making the quantum computers, Professor Oscar Pater. He's a professor of physics and applied physics at Caltech and he's the head of quantum hardware for Amazon. He does research on nanophotonics, quantum optics, and of course quantum computers. Here's my visit to Oscar Painter's lab.

Ah, hey, Oscar, how are you good to see you after so many years.

Ah, hey, Oscar, how are you good to see you after so many years.

Yeah, it's been a while. Huh yeah, well thanks so much for talking with me.

Yeah, it's been a while. Huh yeah, well thanks so much for talking with me.

Yeah, it's been a while. Happy to try to fill you in on some of the things we've been doing in the areas of quantic computing.

Yeah, it's been a while. Happy to try to fill you in on some of the things we've been doing in the areas of quantic computing.

Okay, so the first thing I wanted to talk to him about was just what does the word quantum mean? Because I feel like we're going to need that to understand what a quantum computer is. Now, the word quantum is the word we used to describe how things behave at the level of atoms and the tiny little particles that make up the atoms. So in our everyday lives, we're used to things being solid and us being able to hold them, like, for example, if you take a piece of wood or a ball. But if you take that piece of wood or ball and you chop it up, and you keep chopping it up, you get down to atoms, and then you'll notice that those atoms don't behave in the same way that a piece of wood or a ball do. Here's how Oscar explains it.

Okay, so the first thing I wanted to talk to him about was just what does the word quantum mean? Because I feel like we're going to need that to understand what a quantum computer is. Now, the word quantum is the word we used to describe how things behave at the level of atoms and the tiny little particles that make up the atoms. So in our everyday lives, we're used to things being solid and us being able to hold them, like, for example, if you take a piece of wood or a ball. But if you take that piece of wood or ball and you chop it up, and you keep chopping it up, you get down to atoms, and then you'll notice that those atoms don't behave in the same way that a piece of wood or a ball do. Here's how Oscar explains it.

It turns out that down to the microscopic scale, so not our everyday scale of things, the laws of physics that dominate in that regime is quantum mechanics, and quantum mechanics is a theory that has some strange attributes that we don't experience every day. For example, it postulates that things can be in superposition, so you can have objects being in sort of what we think of as two distinct realities at the same time. Imagine having a particle in one position and another position simultaneously. That seems very odd to us, but in quantum mechanics it's very natural.

It turns out that down to the microscopic scale, so not our everyday scale of things, the laws of physics that dominate in that regime is quantum mechanics, and quantum mechanics is a theory that has some strange attributes that we don't experience every day. For example, it postulates that things can be in superposition, so you can have objects being in sort of what we think of as two distinct realities at the same time. Imagine having a particle in one position and another position simultaneously. That seems very odd to us, but in quantum mechanics it's very natural.

Like, for example, I grabbed this piece of wood in front of me, and it's a piece of wood. It's not two things at the same time. Right, It's in one location.

Like, for example, I grabbed this piece of wood in front of me, and it's a piece of wood. It's not two things at the same time. Right, It's in one location.

Right, it's sitting there. It's firmly right in front of you.

Right, it's sitting there. It's firmly right in front of you.

Right. If I had an atom in front of me or an electron, it wouldn't exactly.

Right. If I had an atom in front of me or an electron, it wouldn't exactly.

You would find that if you repeated the measurement or finding its position multiple times, you might find that, Oh, I get this weird outcome that sometimes I measure it here, sometimes I measure it there. And that's because it's actually in many places at once, all right, And that's fundamental to the description of quantum mechanics. The way I like to think about quantum mechanics is really as waves and amplitudes. So think about you're at a pond and you throw a rock in a pond, and you see this ripple of the rock. Right, That's how I think about, Like the rocks are sort of the particles, and these wave phenomena are sort of the actual physical quantum mechanical description of that particle.

You would find that if you repeated the measurement or finding its position multiple times, you might find that, Oh, I get this weird outcome that sometimes I measure it here, sometimes I measure it there. And that's because it's actually in many places at once, all right, And that's fundamental to the description of quantum mechanics. The way I like to think about quantum mechanics is really as waves and amplitudes. So think about you're at a pond and you throw a rock in a pond, and you see this ripple of the rock. Right, That's how I think about, Like the rocks are sort of the particles, and these wave phenomena are sort of the actual physical quantum mechanical description of that particle.

Like the particle the thing, the atom or the electron. It's not the rock you throw into the pond, no, but it's actually the ripple of the ripple.

Like the particle the thing, the atom or the electron. It's not the rock you throw into the pond, no, but it's actually the ripple of the ripple.

Yeah, that's right, it's this wave. So I may have started with something that was very local, like that rock, but then it becomes very quickly it sort of propagates out and is actually better described as this wave on the pond.

Yeah, that's right, it's this wave. So I may have started with something that was very local, like that rock, but then it becomes very quickly it sort of propagates out and is actually better described as this wave on the pond.

Because like a ripple and a wave in a pond like that, it's kind of in a lot of places at the same.

Because like a ripple and a wave in a pond like that, it's kind of in a lot of places at the same.

Exactly, that's right. And then the interference is important to understand. If I throw two rocks in the pond, then I see the sort of interference of the ripple patterns coming from each rock that blashed in the pond.

Exactly, that's right. And then the interference is important to understand. If I throw two rocks in the pond, then I see the sort of interference of the ripple patterns coming from each rock that blashed in the pond.

Right, Like each ripple starts at simple, but then they start to mix together and form this complex pattern on the surface of the pod.

Right, Like each ripple starts at simple, but then they start to mix together and form this complex pattern on the surface of the pod.

Exactly, like how do they evolve in time?

Exactly, like how do they evolve in time?

Okay, so when you get down to the level of atoms, things behave really strangely. Scientists think of things at that level not as little tiny balls, but as waves or ripples of energy, like the ripples in a pond. Now you may think, wait a minute, if things are kind of wavy and strange at the level of atoms. Why isn't it that way when you get to big stuff like a piece of wood or a ball, And the answer is that they are that way. There's just a lot of atoms in a piece of wood, and from a distance, it gives you the impression that it's solid. It's sort of like how some clouds from afar they might look solid once you get up close to them, they're actually kind of fuzzy and wispy, and all the water droplets are moving around. So that's quantum. Now. A quantum computer is what happens when you make a regular computer, but you make the circuits out of individual atoms or particles like electrons.

Okay, so when you get down to the level of atoms, things behave really strangely. Scientists think of things at that level not as little tiny balls, but as waves or ripples of energy, like the ripples in a pond. Now you may think, wait a minute, if things are kind of wavy and strange at the level of atoms. Why isn't it that way when you get to big stuff like a piece of wood or a ball, And the answer is that they are that way. There's just a lot of atoms in a piece of wood, and from a distance, it gives you the impression that it's solid. It's sort of like how some clouds from afar they might look solid once you get up close to them, they're actually kind of fuzzy and wispy, and all the water droplets are moving around. So that's quantum. Now. A quantum computer is what happens when you make a regular computer, but you make the circuits out of individual atoms or particles like electrons.

Classical computers are formed from things that are very very classical in nature.

Classical computers are formed from things that are very very classical in nature.

And they uperate kind of on hard switches.

And they uperate kind of on hard switches.

Yeah, like, yeah, that's right, the transistors on your phone, And that's what we call these types of elements. The transistors are used to store information or perform calculations, and the transistors are really set by a bunch of electrons in part of the circuit. And usually you're talking about quite a few electrons.

Yeah, like, yeah, that's right, the transistors on your phone, And that's what we call these types of elements. The transistors are used to store information or perform calculations, and the transistors are really set by a bunch of electrons in part of the circuit. And usually you're talking about quite a few electrons.

Because regular transistors are huge. They're bigger than an atom.

Because regular transistors are huge. They're bigger than an atom.

Yes, exactly, that's physically what's going on in your phone. And what I'm telling you is that the way to think about it is in the quantum case, I just have one electron.

Yes, exactly, that's physically what's going on in your phone. And what I'm telling you is that the way to think about it is in the quantum case, I just have one electron.

Like the circuits are made out of individual electrons.

Like the circuits are made out of individual electrons.

Yeah, atoms is exactly what you're doing. Or a quantum particle doesn't have to be electrons, can be other particles. That was the sort of very early idea from people like FIM and others back in the nineteen eighties is if you're going to do this, and you better make them out of quantum mechanical objects to begin with.

Yeah, atoms is exactly what you're doing. Or a quantum particle doesn't have to be electrons, can be other particles. That was the sort of very early idea from people like FIM and others back in the nineteen eighties is if you're going to do this, and you better make them out of quantum mechanical objects to begin with.

Okay, So if you make a computer where the circuits are made of individual quantum objects like atoms or electrons, then you get a quantum computer. And what that does is that it makes their calculations also quantum mechanical. And this is where the concept of a cubit comes in. It's like a regular bit in your computer, and a bit is like a one or zero, but a cubit is a quantum mechanical one or zero.

Okay, So if you make a computer where the circuits are made of individual quantum objects like atoms or electrons, then you get a quantum computer. And what that does is that it makes their calculations also quantum mechanical. And this is where the concept of a cubit comes in. It's like a regular bit in your computer, and a bit is like a one or zero, but a cubit is a quantum mechanical one or zero.

Classical computers are formed from digital bits and they go between one and zero. A quantum computer doesn't have these hard zero one states. It has every possibility in between. So imagine if we have these two states zero in one. I told you that a quantum system can be in two different states at once, right, So it can be in zero and one at the same time, and I can have a different weight of zero or one at the same time. It could be ten percent zero, ninety percent one.

Classical computers are formed from digital bits and they go between one and zero. A quantum computer doesn't have these hard zero one states. It has every possibility in between. So imagine if we have these two states zero in one. I told you that a quantum system can be in two different states at once, right, So it can be in zero and one at the same time, and I can have a different weight of zero or one at the same time. It could be ten percent zero, ninety percent one.

It's like a shade of gray.

It's like a shade of gray.

Yeah, And so you have all those possibilities in between. It can be zero or one or anything in between.

Yeah, And so you have all those possibilities in between. It can be zero or one or anything in between.

It can be black, white, dark, gray, light.

It can be black, white, dark, gray, light.

Gray, exactly, So it has all those shape in between. You can take zero with some fraction and add it to one with any other fraction. You can have any combination of that.

Gray, exactly, So it has all those shape in between. You can take zero with some fraction and add it to one with any other fraction. You can have any combination of that.

So on a regular computer, if you multiply two bits together, it's like you're multiplying two fixed numbers together, like three times four. But in a quantum computer, when you multiply two cubits together, it's like you're multiplying two things that can be lots of numbers at the same time. So, for example, it's like you're multiplying every number from zero to one hundred times every number from zero to one thousand, all at the same time in one operation. That's what makes quantum computers unique. They take this weirdness of the quantum world and then let's you do math with it. Now, Actually, it's not doing all of those multiplications or calculations at the same time. It's more like how Oscar described it earlier. If you drop two rocks in a pond, you see the two ripples spread out and mix together to form a complex ripple pattern. That's more of the picture of what a quantum comp does. It doesn't do calculations with hard numbers. It does calculations with the ripples and patterns of quantum numbers. Of course, my next question for Oscar was what is that good for? Why would you want to do math this way? When we come back, I'm going to ask Oscar what quantum computers are for, and then at the end we're going to go check out the ones he's built. You're listening to sign stuff. Welcome back. Okay, to recap, we learned that a quantum computer is a regular computer whose circuits are made with individual atoms or small particles like electrons, and by doing that you can do quantum calculations. That is, you can do math, but with numbers that are actually lots of different numbers at the same time. So now the question is, why would you want to do that? What are quantum computers? Four? Here's more of my conversation, but quantum physicist Oscar Painter. Let's say it's a few years into the future and we have quantum computers, yes, in our phones, like I have one in my podget Okay, what can I do with it? And how is my life different?

So on a regular computer, if you multiply two bits together, it's like you're multiplying two fixed numbers together, like three times four. But in a quantum computer, when you multiply two cubits together, it's like you're multiplying two things that can be lots of numbers at the same time. So, for example, it's like you're multiplying every number from zero to one hundred times every number from zero to one thousand, all at the same time in one operation. That's what makes quantum computers unique. They take this weirdness of the quantum world and then let's you do math with it. Now, Actually, it's not doing all of those multiplications or calculations at the same time. It's more like how Oscar described it earlier. If you drop two rocks in a pond, you see the two ripples spread out and mix together to form a complex ripple pattern. That's more of the picture of what a quantum comp does. It doesn't do calculations with hard numbers. It does calculations with the ripples and patterns of quantum numbers. Of course, my next question for Oscar was what is that good for? Why would you want to do math this way? When we come back, I'm going to ask Oscar what quantum computers are for, and then at the end we're going to go check out the ones he's built. You're listening to sign stuff. Welcome back. Okay, to recap, we learned that a quantum computer is a regular computer whose circuits are made with individual atoms or small particles like electrons, and by doing that you can do quantum calculations. That is, you can do math, but with numbers that are actually lots of different numbers at the same time. So now the question is, why would you want to do that? What are quantum computers? Four? Here's more of my conversation, but quantum physicist Oscar Painter. Let's say it's a few years into the future and we have quantum computers, yes, in our phones, like I have one in my podget Okay, what can I do with it? And how is my life different?

I think that's a very unlikely scenario.

I think that's a very unlikely scenario.

Okay.

Okay.

I think that's the wrong way.

I think that's the wrong way.

To think about how quantic computers might change our lives, at least as far as I can project into the future. Okay, I think the best way to think about a quantic computer as we envision it right now is that it will be more.

To think about how quantic computers might change our lives, at least as far as I can project into the future. Okay, I think the best way to think about a quantic computer as we envision it right now is that it will be more.

Like a supercomputer.

Like a supercomputer.

So a supercomputer is just a very large computer that can perform calculations beyond what our desktop, our personal computers can do. And these are usually very large, almost building scale computers and computer clusters that have many, many different processing units that are all integrated together, and through that scale you can perform a huge number of computations per second and therefore compute some of the hardest problems.

So a supercomputer is just a very large computer that can perform calculations beyond what our desktop, our personal computers can do. And these are usually very large, almost building scale computers and computer clusters that have many, many different processing units that are all integrated together, and through that scale you can perform a huge number of computations per second and therefore compute some of the hardest problems.

That are out there.

That are out there.

A lot of them are used for chemistry problems. They're used to study particle physics, so fundamental physics, trying to understand models of quantum particles that are beyond the current standard model. They're used to compute the properties of materials, climate modeling, and things like that.

A lot of them are used for chemistry problems. They're used to study particle physics, so fundamental physics, trying to understand models of quantum particles that are beyond the current standard model. They're used to compute the properties of materials, climate modeling, and things like that.

So usually science and tech, yeahs, And.

So usually science and tech, yeahs, And.

There's always this competition between different nations who has the fastest or the biggest supercomputer.

There's always this competition between different nations who has the fastest or the biggest supercomputer.

I see, So you envision quantum computers will be sort of like a specialized version of computer.

I see, So you envision quantum computers will be sort of like a specialized version of computer.

It's going to be some very special type of supercomputer that can solve specific problems that quantum computers will be very effective at that we can't do today on classic computers, no matter how much we scale them up. And the key is it's not just a faster supercomputer. It performs calculations in a fundamentally different way, and therefore it can tackle problems that are possibly outside of the reach of these conventional classical supercomputers.

It's going to be some very special type of supercomputer that can solve specific problems that quantum computers will be very effective at that we can't do today on classic computers, no matter how much we scale them up. And the key is it's not just a faster supercomputer. It performs calculations in a fundamentally different way, and therefore it can tackle problems that are possibly outside of the reach of these conventional classical supercomputers.

What do you mean? Out of the reach meaning that.

What do you mean? Out of the reach meaning that.

No matter how fast they get or how big they get, they'll never be able to compute some of these problems, never or take an infinite exactly, it's just the scaling is so bad for these problems, you would take way too long and require way too large on machine. So, no matter how hard we work on our current computing technology, it has limits and it's known and you can prove it for certain problems, and quantic computers when they looked at theoretically these same problems, they realize that the same restrictions or limitations for quantic computers are not there. There's examples where we believe and strongly believe that certain mathematical problems that are important are really really hard to perform and can't be solved using classical means, no matter how much we improve the technology.

No matter how fast they get or how big they get, they'll never be able to compute some of these problems, never or take an infinite exactly, it's just the scaling is so bad for these problems, you would take way too long and require way too large on machine. So, no matter how hard we work on our current computing technology, it has limits and it's known and you can prove it for certain problems, and quantic computers when they looked at theoretically these same problems, they realize that the same restrictions or limitations for quantic computers are not there. There's examples where we believe and strongly believe that certain mathematical problems that are important are really really hard to perform and can't be solved using classical means, no matter how much we improve the technology.

No matter if I have a building full of supercomputers, yeah exactly, you'll never be able.

No matter if I have a building full of supercomputers, yeah exactly, you'll never be able.

To just fill the world with them. You still won't be able to do it. Yet a quantic computer can solve it pretty efficiently.

To just fill the world with them. You still won't be able to do it. Yet a quantic computer can solve it pretty efficiently.

Well. Step me through some of these problems.

Well. Step me through some of these problems.

Like so the example that everyone points to, and it is pretty amazing that people found this, But there's this mathematical problem. It just happens to be very applicable to our safety or security of our data. So it turns out that most of the security of all of the data that you hold, all the data that banks or various institutions around the world want to be safe and protected, they typically encrypt it. And those encryption techniques that have been used were what are called RSA encryption, where you want to take a large number and understand what its prime factors are.

Like so the example that everyone points to, and it is pretty amazing that people found this, But there's this mathematical problem. It just happens to be very applicable to our safety or security of our data. So it turns out that most of the security of all of the data that you hold, all the data that banks or various institutions around the world want to be safe and protected, they typically encrypt it. And those encryption techniques that have been used were what are called RSA encryption, where you want to take a large number and understand what its prime factors are.

Okay, so the first big thing that quantum computers can be useful, the one that got people really excited about them in the nineties, is in breaking password encryption. So whenever you enter your password on a website or when you download your bank statement, that information is encrypted or scrambled so that if anyone happens to catch that information, they can't tell what it says. And the whole scheme is based on the idea that if I gave you a really large number, it's really hard to find what its prime factors are. Here's how Oscar explains it, but just to give you a quick heads up, a prime number is a number that can't be divided except by itself or by one. So, for example, thirteen is a prime number because you can't fight thirteen by anything except thirteen and one, And the same goes for seventeen nineteen twenty three and so on. Anyways, here's Oscar explaining it.

Okay, so the first big thing that quantum computers can be useful, the one that got people really excited about them in the nineties, is in breaking password encryption. So whenever you enter your password on a website or when you download your bank statement, that information is encrypted or scrambled so that if anyone happens to catch that information, they can't tell what it says. And the whole scheme is based on the idea that if I gave you a really large number, it's really hard to find what its prime factors are. Here's how Oscar explains it, but just to give you a quick heads up, a prime number is a number that can't be divided except by itself or by one. So, for example, thirteen is a prime number because you can't fight thirteen by anything except thirteen and one, And the same goes for seventeen nineteen twenty three and so on. Anyways, here's Oscar explaining it.

So I give you a number and I say, tell me what the prime factors are, and you have to break it down to its prime factors. So you know, a simple one is, you know, like two, it's just one times two, one and two. Those are the two prime factors, right. But it gets harder as these numbers get bigger.

So I give you a number and I say, tell me what the prime factors are, and you have to break it down to its prime factors. So you know, a simple one is, you know, like two, it's just one times two, one and two. Those are the two prime factors, right. But it gets harder as these numbers get bigger.

If I tell you one millions be round there and forty three.

If I tell you one millions be round there and forty three.

Yeah, seventeen, very hard to actually answer what those what the prime factors are. But if I give you the prime factors, you can multiply them together and very quickly get the answer to what that larger number is.

Yeah, seventeen, very hard to actually answer what those what the prime factors are. But if I give you the prime factors, you can multiply them together and very quickly get the answer to what that larger number is.

Right.

Right.

And so if you know the prime factors, I can give you what they multiply to.

And so if you know the prime factors, I can give you what they multiply to.

But if you give me.

But if you give me.

The number that they multiply to without then I have a very hard time finding out what the prime factors are.

The number that they multiply to without then I have a very hard time finding out what the prime factors are.

Because you'd have to get kind of have to guess.

Because you'd have to get kind of have to guess.

Well, you know, there's mathematical techniques to try to find these, but they're very inefficient.

Well, you know, there's mathematical techniques to try to find these, but they're very inefficient.

And so it turns.

And so it turns.

Out that most of the security of the way we encrypt information is based upon that asymmetry. And how hard the problem is.

Out that most of the security of the way we encrypt information is based upon that asymmetry. And how hard the problem is.

So, now, let's say somebody has a quantum computer.

So, now, let's say somebody has a quantum computer.

Right, then they can find those prime factors and they can now decrypt all that information.

Right, then they can find those prime factors and they can now decrypt all that information.

They can just grab it from the air, yeah, and be like, oh, I know.

They can just grab it from the air, yeah, and be like, oh, I know.

And yeah, I can find the prime factors and then I can use that to decrypt the information.

And yeah, I can find the prime factors and then I can use that to decrypt the information.

That would be easy for a quantum computer, and you just press a button and will tell you, oh, this is an oscar or his secret decoder.

That would be easy for a quantum computer, and you just press a button and will tell you, oh, this is an oscar or his secret decoder.

Yeah, exactly, So that would you know. That obviously concerned a lot of people when that algorithm was developed.

Yeah, exactly, So that would you know. That obviously concerned a lot of people when that algorithm was developed.

Okay, this gets a little bit heavy into encryption and quantum algorithms, but the main point is that most of the security of our passwords and our sensitive information, and also the encryption of things like bitcoin and all those cryptocurrencies, they all depend on this one math problem which is really hard for regular computers even supercomputers to solve. And that is a problem of finding the two prime numbers that multiply to get a really large number. But then in nineteen ninety five, a computer scientist named Peter Shore publish the paper titled Polynomial time Algorithms for prime factorization of discrete logarithms. On a quantum computer, which essentially showed that if you have a quantum computer, you can solve this problem in a short amount of time. And this is probably the main reason that people have been rushing to make quantum computers since then, because imagine if everyone in the world, people, companies, countries are all protecting their secrets using the same trick, but you had a special quantum computer that could break that trick, you could rule the world. Now, the details of how Peter Shore's algorithm works are a little complicated to explain here, but the essence of it is that you're using the ripples on a pawn nature of quantum numbers on a quantum computer to basically try out every possible combination for how to break your secret encryption, and you use some clever math tricks so that these ripples combine and mix together until the right answer pops out. So that is the main reason that people are excited about quantum computers. But there are other reasons and other possible applications, So here's Oscar telling me about them.

Okay, this gets a little bit heavy into encryption and quantum algorithms, but the main point is that most of the security of our passwords and our sensitive information, and also the encryption of things like bitcoin and all those cryptocurrencies, they all depend on this one math problem which is really hard for regular computers even supercomputers to solve. And that is a problem of finding the two prime numbers that multiply to get a really large number. But then in nineteen ninety five, a computer scientist named Peter Shore publish the paper titled Polynomial time Algorithms for prime factorization of discrete logarithms. On a quantum computer, which essentially showed that if you have a quantum computer, you can solve this problem in a short amount of time. And this is probably the main reason that people have been rushing to make quantum computers since then, because imagine if everyone in the world, people, companies, countries are all protecting their secrets using the same trick, but you had a special quantum computer that could break that trick, you could rule the world. Now, the details of how Peter Shore's algorithm works are a little complicated to explain here, but the essence of it is that you're using the ripples on a pawn nature of quantum numbers on a quantum computer to basically try out every possible combination for how to break your secret encryption, and you use some clever math tricks so that these ripples combine and mix together until the right answer pops out. So that is the main reason that people are excited about quantum computers. But there are other reasons and other possible applications, So here's Oscar telling me about them.

Another example is maybe more natural to think about, and this is where quantum computers were first proposed. It to be interesting or useful, and that is the simulation of nature itself. Nature as we know it is not classical. If you peel the layers of the onion enough and you get down to the core, right to the atomic scale, it turns out that the laws of physics that dominates quantum mechanics, okay, like the actual mathematics of that, when you describe it, when you have many particles, it quickly becomes something that you can't simulate with a classical computer. So all those interference of all the particles and keeping track of all of that. A classical computer, if you try to simulate that, you quickly run out of steam and it becomes an exponentially hard problem. And so you know, a classical computer is just ill suited.

Another example is maybe more natural to think about, and this is where quantum computers were first proposed. It to be interesting or useful, and that is the simulation of nature itself. Nature as we know it is not classical. If you peel the layers of the onion enough and you get down to the core, right to the atomic scale, it turns out that the laws of physics that dominates quantum mechanics, okay, like the actual mathematics of that, when you describe it, when you have many particles, it quickly becomes something that you can't simulate with a classical computer. So all those interference of all the particles and keeping track of all of that. A classical computer, if you try to simulate that, you quickly run out of steam and it becomes an exponentially hard problem. And so you know, a classical computer is just ill suited.

To doing that.

To doing that.

But a quantum computer that's made out of the same those sort of particles that can do with that interference naturally, you know, has a natural advantage in terms of using it to simulate the natural world at its quantum mechanical core.

But a quantum computer that's made out of the same those sort of particles that can do with that interference naturally, you know, has a natural advantage in terms of using it to simulate the natural world at its quantum mechanical core.

Why would I want to do that?

Why would I want to do that?

Yeah, So that's the questions like, okay, so that's great, but why would I want to do that other than maybe I want to understand physics better? Well, this idea that I want to understand how material behaves is a very good example. If I'm building an electrical circuit, or I'm building a new battery, or I'm building a different energy process inside of a material or energy storage device. A lot of times that depends on what the electrons are doing. If I want to understand or something unique when I describe them quantum mechanically, maybe there's special properties I'm just totally blind to. So if I wanted to make a better superconnecting material, something that can carry electricity with no resistance, right, maybe we can have magnetically livitated trains. Maybe you can have you know, really efficient electrical circuits that don't dissipate any energy.

Yeah, So that's the questions like, okay, so that's great, but why would I want to do that other than maybe I want to understand physics better? Well, this idea that I want to understand how material behaves is a very good example. If I'm building an electrical circuit, or I'm building a new battery, or I'm building a different energy process inside of a material or energy storage device. A lot of times that depends on what the electrons are doing. If I want to understand or something unique when I describe them quantum mechanically, maybe there's special properties I'm just totally blind to. So if I wanted to make a better superconnecting material, something that can carry electricity with no resistance, right, maybe we can have magnetically livitated trains. Maybe you can have you know, really efficient electrical circuits that don't dissipate any energy.

All of these things.

All of these things.

Then I would have to use a quantum computer to model that behavior.

Then I would have to use a quantum computer to model that behavior.

And you said there's some maybe potential applications in chemistry and biology.

And you said there's some maybe potential applications in chemistry and biology.

Yeah, you know, if I think about what is going on when I have a chemical reaction, usually it comes down to the electrons, and I need to understand what they're doing in order to understand, you know, whether this chemical reaction is going to be efficient or not, or if I want to describe it with chemical accuracy, so I can use it to, you know, do some sort of industrial chemical process. The biological application. It's like, if I want to know how molecules are biologically relevant molecules lined together, then potentially I need to know more information about the electronic behavior in these molecules. If I wanted to do that without having approximation or much higher accuracy than a quantum computer would be potentially more capable.

Yeah, you know, if I think about what is going on when I have a chemical reaction, usually it comes down to the electrons, and I need to understand what they're doing in order to understand, you know, whether this chemical reaction is going to be efficient or not, or if I want to describe it with chemical accuracy, so I can use it to, you know, do some sort of industrial chemical process. The biological application. It's like, if I want to know how molecules are biologically relevant molecules lined together, then potentially I need to know more information about the electronic behavior in these molecules. If I wanted to do that without having approximation or much higher accuracy than a quantum computer would be potentially more capable.

There I we might be able to predict better how a vaccine will work, or whether a certain chemical introduce in your body will.

There I we might be able to predict better how a vaccine will work, or whether a certain chemical introduce in your body will.

Right now, we don't have that sort of level of specificity. I mean, we'd love too. People are proposing techniques, but that's the right idea, by the devil's in the details. And you know, you have people saying, well, look, you know, I think even today there's I won't call them skeptics, but there's a lot of people that are saying, well, I can keep improving my classical algorithms, and whether you can really gain advantage from the quantum simulations is a it's a practical question, and maybe we don't have as clear an example or as clear a win when it comes to how quantum computers will will do better, or be more efficient, or be able to do the calculations fast or even do them ones that the classical computers can't do. But I think there's definitely something there. It's just that we still have to work on a quantum algorithms. It's not as clear cut, I would say.

Right now, we don't have that sort of level of specificity. I mean, we'd love too. People are proposing techniques, but that's the right idea, by the devil's in the details. And you know, you have people saying, well, look, you know, I think even today there's I won't call them skeptics, but there's a lot of people that are saying, well, I can keep improving my classical algorithms, and whether you can really gain advantage from the quantum simulations is a it's a practical question, and maybe we don't have as clear an example or as clear a win when it comes to how quantum computers will will do better, or be more efficient, or be able to do the calculations fast or even do them ones that the classical computers can't do. But I think there's definitely something there. It's just that we still have to work on a quantum algorithms. It's not as clear cut, I would say.

So those are the two main applications or uses for planted computers. One is in breaking encryption using a special algorithm called phase estimation that only works in a quantum computer, and the other is to simulate nature, because nature is, after all quantum at its core, and so scientists think that quantum computers will let us better simulate how atoms and electrons interact so that we can design better materials, better semiconductors, and maybe better medicines. Now, I said so far, because this is all still very new, and there might be other classes of problems like the encryption problem where quantum computers are just fundamentally and exponentially better at solving, but nobody knows for sure. Of course, it's all hinges on whether or not we can actually make quantum computers at the level that they would actually be useful and most important, reliable. So now we're going to go actually see these quantum computers that Oscar is building, and he's going to tell us why they're hard to make and why they're so prone to making errors. But first, let's take a quick break. You're listening to science stuff and we're back. Well I heard you have a quantum computer in your basement.

So those are the two main applications or uses for planted computers. One is in breaking encryption using a special algorithm called phase estimation that only works in a quantum computer, and the other is to simulate nature, because nature is, after all quantum at its core, and so scientists think that quantum computers will let us better simulate how atoms and electrons interact so that we can design better materials, better semiconductors, and maybe better medicines. Now, I said so far, because this is all still very new, and there might be other classes of problems like the encryption problem where quantum computers are just fundamentally and exponentially better at solving, but nobody knows for sure. Of course, it's all hinges on whether or not we can actually make quantum computers at the level that they would actually be useful and most important, reliable. So now we're going to go actually see these quantum computers that Oscar is building, and he's going to tell us why they're hard to make and why they're so prone to making errors. But first, let's take a quick break. You're listening to science stuff and we're back. Well I heard you have a quantum computer in your basement.

Well not in my basement, but in my my laboratory. Yeah, here, can we go see it?

Well not in my basement, but in my my laboratory. Yeah, here, can we go see it?

We can?

We can?

Okay, yeah, let's get see it.

Okay, yeah, let's get see it.

Okay, you want to do that?

Okay, you want to do that?

Okay, so where are we going?

Okay, so where are we going?

Just the next door.

Just the next door.

We don't actually even have to go down into.

We don't actually even have to go down into.

The basement, into the basement, no.

The basement, into the basement, no.

Basement sound and more.

Basement sound and more.

Yeah, i'd scientists exactly.

Yeah, i'd scientists exactly.

So let's all these labs have different variants of quantic computers that we're testing. Multiple quantum computers here, yeah, yeah, not just one. So there's small scale quantum computers, but the largest ones are you know, ones at at Amazon or Google or IBM or you know some of the other startup companies. These get to be maybe a factor of ten times larger than the ones I'll show you. Okay, okay, so this gives you an idea. All of these control electronics, right is to use to control about twenty of these quantum bits.

So let's all these labs have different variants of quantic computers that we're testing. Multiple quantum computers here, yeah, yeah, not just one. So there's small scale quantum computers, but the largest ones are you know, ones at at Amazon or Google or IBM or you know some of the other startup companies. These get to be maybe a factor of ten times larger than the ones I'll show you. Okay, okay, so this gives you an idea. All of these control electronics, right is to use to control about twenty of these quantum bits.

There's twenty quantum meaning twenty particle. A machine made up of twenty quantum particles.

There's twenty quantum meaning twenty particle. A machine made up of twenty quantum particles.

Corract right, which we are manipulating as quantum bits, and that circuit lives down inside of this special refrigerator.

Corract right, which we are manipulating as quantum bits, and that circuit lives down inside of this special refrigerator.

Okay, So if you've ever seen, or if you google a picture of a quantum computer, most likely what you see is something that looks like an upside down metal wedding cake with circular tears or platforms that get smaller and smaller as they hang down from the ceiling. That is basically a super intense refrigerator. The whole purpose of it is to get the tip of that upside down cake really really really cold.

Okay, So if you've ever seen, or if you google a picture of a quantum computer, most likely what you see is something that looks like an upside down metal wedding cake with circular tears or platforms that get smaller and smaller as they hang down from the ceiling. That is basically a super intense refrigerator. The whole purpose of it is to get the tip of that upside down cake really really really cold.

And this refrigerator is under vacuum, under high vacuum. It's a temperature which is about ten million degrees above absolute zero.

And this refrigerator is under vacuum, under high vacuum. It's a temperature which is about ten million degrees above absolute zero.

Ten degrees.

Ten degrees.

So to give you an idea, So if I go to the deepest part of space, it's a few degrees calvin, a few degrees above that food and zero, the coldest darkest parts of outer space or that universe. Yeah, but this thing's about thirty times colder than that.

So to give you an idea, So if I go to the deepest part of space, it's a few degrees calvin, a few degrees above that food and zero, the coldest darkest parts of outer space or that universe. Yeah, but this thing's about thirty times colder than that.

Even WHOA So would you say that some of the cold this places in the whole universe.

Even WHOA So would you say that some of the cold this places in the whole universe.

I mean no, I mean you can get there's people that do this for a living that make really cold things.

I mean no, I mean you can get there's people that do this for a living that make really cold things.

But this is among the very very coldest things. Okay, yeah, but this is extremely cold.

But this is among the very very coldest things. Okay, yeah, but this is extremely cold.

What does it need to be cold?

What does it need to be cold?

Because even the lights, even if we turned all the lights off, even just the fact that the room's hot, it's.

Because even the lights, even if we turned all the lights off, even just the fact that the room's hot, it's.

Room temperature, but it radiates.

Room temperature, but it radiates.

Radiation, and that radiation would completely destroy the information in the corner bit.

Radiation, and that radiation would completely destroy the information in the corner bit.

I see. We have to get it really dark.

I see. We have to get it really dark.

We have to make sure that there's not any of this thermal energy that's making it into the circuit, otherwise it'll destroy the manipulation of those quantum parties. And so it has to be as isolated as we can from the environment. We would ideally seal it off from everything, so it would be like zero temperature and there would be nothing coming in other than what we want to send to it to control it.

We have to make sure that there's not any of this thermal energy that's making it into the circuit, otherwise it'll destroy the manipulation of those quantum parties. And so it has to be as isolated as we can from the environment. We would ideally seal it off from everything, so it would be like zero temperature and there would be nothing coming in other than what we want to send to it to control it.

And then you can see there's all of these cables, uh huh. Each of these feeds.

And then you can see there's all of these cables, uh huh. Each of these feeds.

Into a microwave cable that could use to control individual quantum bits or quantum particles on the circuit.

Into a microwave cable that could use to control individual quantum bits or quantum particles on the circuit.

So what I'm looking at is a room full of electronics and cables, and in the center is a massive structure with two suspended eye beams, and hanging from those beams is the upside down wedding cake I mentioned before, which in this case is sealed inside a really thick metal cylinder, and inside that cylinder at the very tip of the wedding cake cool to almost the coldest anything can be in the whole universe. Is a little chip? Good a quantum computer?

So what I'm looking at is a room full of electronics and cables, and in the center is a massive structure with two suspended eye beams, and hanging from those beams is the upside down wedding cake I mentioned before, which in this case is sealed inside a really thick metal cylinder, and inside that cylinder at the very tip of the wedding cake cool to almost the coldest anything can be in the whole universe. Is a little chip? Good a quantum computer?

Well?

Well?

What's in there? So describe me what's inside the core of it? Is it like a little chip? Yeah?

What's in there? So describe me what's inside the core of it? Is it like a little chip? Yeah?

Like love.

Like love.

It's what's called a superconnecting quantum circuit. So it uses little metal traces on a silicon wafer that we pattern on the surface, and when you get them cold enough, they become super connecting, which means they can carry electrical currents.

It's what's called a superconnecting quantum circuit. So it uses little metal traces on a silicon wafer that we pattern on the surface, and when you get them cold enough, they become super connecting, which means they can carry electrical currents.

Without any energy dissipation.

Without any energy dissipation.

Okay, And it turns out that you can form these sort of quantum particles like these atoms, where the current is circulating in a clockwise way inside of a little tiny ring, or it's circulating counterclockwise, and the clockwise could be zero, when the counterclockwise could be one, and you can get in any superposition of these two circulation patterns, and I can use then I can manipulate what the superposition is, and I can have interact with other circulating currents.

Okay, And it turns out that you can form these sort of quantum particles like these atoms, where the current is circulating in a clockwise way inside of a little tiny ring, or it's circulating counterclockwise, and the clockwise could be zero, when the counterclockwise could be one, and you can get in any superposition of these two circulation patterns, and I can use then I can manipulate what the superposition is, and I can have interact with other circulating currents.

To the things in our circuit.

To the things in our circuit.

There are a few hundred microns in size, so they might be a few times the human hair diameter, so they're pretty big relative to conventional transistors. It's made out of many atoms, but it behaves like a single atom.

There are a few hundred microns in size, so they might be a few times the human hair diameter, so they're pretty big relative to conventional transistors. It's made out of many atoms, but it behaves like a single atom.

Okay, yeah, the way to think about it.

Okay, yeah, the way to think about it.

So there's like a little array of these things, a.

So there's like a little array of these things, a.

Little array of these things on the surface of a microchip, and then each of them we can control the current flow. So what are called single cubit gates. We bring them together and then let them interact them bring them apart. So I need to be able to manipulate the single particle, put it in any sort of superposition I want.

Little array of these things on the surface of a microchip, and then each of them we can control the current flow. So what are called single cubit gates. We bring them together and then let them interact them bring them apart. So I need to be able to manipulate the single particle, put it in any sort of superposition I want.

And then you have to read out the state of these cubits too.

And then you have to read out the state of these cubits too.

You have to know after I do my computation, are you in state zero or state one? All right, I have to ask that question for all my cubits, and that will give me the answer.

You have to know after I do my computation, are you in state zero or state one? All right, I have to ask that question for all my cubits, and that will give me the answer.

I see what is that hearing?

I see what is that hearing?

So this is called the pulse tube cooler sownders sounds like if you were ever a kid growing up in the eighties and you watch Battlestar Galactica or the Cylons and Battlestar Galactica, they do they walk, and they would have this flashing light and they'd have this sort of sound coming from them.

So this is called the pulse tube cooler sownders sounds like if you were ever a kid growing up in the eighties and you watch Battlestar Galactica or the Cylons and Battlestar Galactica, they do they walk, and they would have this flashing light and they'd have this sort of sound coming from them.

This is a similar sort of sound.

This is a similar sort of sound.

This is a pulse tube cooler and it's shooting a slug of helium gas onto a cold plate and then in doing so, when it expands, it can cause cooling. It's analogous to what you do with the regular refrigerator. That's the first stage of cooling, though that only gets you down to maybe a tenth of the temperature of the room. And then if I want to go even cooler down and by another factor of ten or one hundred, then you have to use a recirculating gas.

This is a pulse tube cooler and it's shooting a slug of helium gas onto a cold plate and then in doing so, when it expands, it can cause cooling. It's analogous to what you do with the regular refrigerator. That's the first stage of cooling, though that only gets you down to maybe a tenth of the temperature of the room. And then if I want to go even cooler down and by another factor of ten or one hundred, then you have to use a recirculating gas.

In this case, it's a dilution fridge that takes mixtures of isotopes.

In this case, it's a dilution fridge that takes mixtures of isotopes.

Of helium helium three and helium four, and when they mix, there's an entropy of reaction and that's what gets you down to this lowest temperatures I mentioned.

Of helium helium three and helium four, and when they mix, there's an entropy of reaction and that's what gets you down to this lowest temperatures I mentioned.

So it's several stages. Something like take a fridge put it inside of another fridge.

So it's several stages. Something like take a fridge put it inside of another fridge.

So there's actually like sort of three or four stages of if you're inside of a fridge and you have instead of the fridge, the one fridge is too hot for the other fridge, so we have to isolate them, and then we have to do that for every successive stage.

So there's actually like sort of three or four stages of if you're inside of a fridge and you have instead of the fridge, the one fridge is too hot for the other fridge, so we have to isolate them, and then we have to do that for every successive stage.

It's like, if I take my freezer and I put it inside of like a restaurant freezer, just be colder.

It's like, if I take my freezer and I put it inside of like a restaurant freezer, just be colder.

Yeah, okay, exactly, I keep doing that. I add, you know, another.

Yeah, okay, exactly, I keep doing that. I add, you know, another.

Way, the fridge inside of my fridge have a restaurant freezer.

Way, the fridge inside of my fridge have a restaurant freezer.

And I keep you know, each of them has the ability to get colder and colder. Yeah, So you have to do it in stages. Otherwise, if you try to do a direct shot, it's too much of a thermal load on the system.

And I keep you know, each of them has the ability to get colder and colder. Yeah, So you have to do it in stages. Otherwise, if you try to do a direct shot, it's too much of a thermal load on the system.

I see. So that's a quantum computer in action. Most of what you see when you look at a picture of a quantum computer, it's all the machinery needed to keep the actual circuit in a near perfect vacuum and as cold as possible, and all of that is to completely isolate the quantum computer from the outside world. We'll get to why you need to do that with a quantum computer. But first I was curious how much a quantum computer like this costs. Here's what oscars it. Well, this is definitely much bigger than my phone.

I see. So that's a quantum computer in action. Most of what you see when you look at a picture of a quantum computer, it's all the machinery needed to keep the actual circuit in a near perfect vacuum and as cold as possible, and all of that is to completely isolate the quantum computer from the outside world. We'll get to why you need to do that with a quantum computer. But first I was curious how much a quantum computer like this costs. Here's what oscars it. Well, this is definitely much bigger than my phone.

Yes, exactly.

Yes, exactly.

That's why I was saying, you're probably not going to carry one of these things around.

That's why I was saying, you're probably not going to carry one of these things around.

How much is this something like this if I wanted to build one in my garage?

How much is this something like this if I wanted to build one in my garage?

Okay, Well, you know there's always a big difference between science money and money that you know, when you're talking about conservative products that have large volumes. I remember the first time we purchased a big piece of equipment from my lab when I was the first a faculty member.

Okay, Well, you know there's always a big difference between science money and money that you know, when you're talking about conservative products that have large volumes. I remember the first time we purchased a big piece of equipment from my lab when I was the first a faculty member.

It was about the same.

It was about the same.

It was about smaller than this thing, so smaller than a few cubic feet, but it was more expensive than my house when I bought it.

It was about smaller than this thing, so smaller than a few cubic feet, but it was more expensive than my house when I bought it.

So there's a big difference. Cot So just keep that in mind.

So there's a big difference. Cot So just keep that in mind.

But one of these systems today, because it's very specialized, probably costs about a.

But one of these systems today, because it's very specialized, probably costs about a.

Million dollars set up.

Million dollars set up.

Wow, that's another reason why you will probably wont carry it around in your pocket any times soon. But it's an important actually point to make, is that people will build these systems and go to the larger scales. They can and spend a lot of money to try to do the first demonstrations, but we'll have to shrink them and make the more cost effective all the components that go in.

Wow, that's another reason why you will probably wont carry it around in your pocket any times soon. But it's an important actually point to make, is that people will build these systems and go to the larger scales. They can and spend a lot of money to try to do the first demonstrations, but we'll have to shrink them and make the more cost effective all the components that go in.

Eventually, it's like we did for any algorithm.

Eventually, it's like we did for any algorithm.

Yeah, exactly, and that part will happen. It just requires you to start building these larger systems and for the companies that are making the individual components for them to have larger volumes so they can.

Yeah, exactly, and that part will happen. It just requires you to start building these larger systems and for the companies that are making the individual components for them to have larger volumes so they can.

Drive on costs.

Drive on costs.

But where it's particularly challenging right now is actually in the control electronics. Like the costs about maybe ten thousand dollars a little more than ten.

But where it's particularly challenging right now is actually in the control electronics. Like the costs about maybe ten thousand dollars a little more than ten.

Thousand dollars just for the control used for every single fewbit.

Thousand dollars just for the control used for every single fewbit.

Wow, and we need to go to maybe a million few bits or something. So that's like ten billion dollars just in the control hardware right if we were.

Wow, and we need to go to maybe a million few bits or something. So that's like ten billion dollars just in the control hardware right if we were.

To scale out what we have today.

To scale out what we have today.

So it's very costly to imagine doing that, so right now, yeah, but then we'll get better. We'll do custom silicon chips, where the costs are in the scale of the electronics is much more efficient, So we'll do what are called ASEX or custom circuits that'll drive down costs tremendously, but yeah, that that has to happen, but it just you know, it's not We're not quite there yet.

So it's very costly to imagine doing that, so right now, yeah, but then we'll get better. We'll do custom silicon chips, where the costs are in the scale of the electronics is much more efficient, So we'll do what are called ASEX or custom circuits that'll drive down costs tremendously, but yeah, that that has to happen, but it just you know, it's not We're not quite there yet.

So there you have it. You can build a quantum computer in your garage right now for about a million dollars, although for that money right now, you could only put about twenty cubits on it, which is about as sophisticated as an abocus, although this case would be a quantum ebicus. Right. The last thing we'll talk about is why quantum computers are so hard to make. If they can break any encryption on the planet, or potentially let us simulate new chemicals and materials, why haven't we done it? What is so hard about making a quantum computer? Here's Oscar explaining it.

So there you have it. You can build a quantum computer in your garage right now for about a million dollars, although for that money right now, you could only put about twenty cubits on it, which is about as sophisticated as an abocus, although this case would be a quantum ebicus. Right. The last thing we'll talk about is why quantum computers are so hard to make. If they can break any encryption on the planet, or potentially let us simulate new chemicals and materials, why haven't we done it? What is so hard about making a quantum computer? Here's Oscar explaining it.

Probably the thing that makes it most difficult, and maybe it's the most relevant to talk about, is that let's say you want to do a computation with a quantum computer, and you want to describe it by a certain number of particles, and you want to use those particles to do your quantum simulation. Then you need to be able to control those particles right, to manipulate them to do the computation you want. But if those particles interact with the environment, then part of the information that you wanted to control or manipulate will actually evolve and become connected to.

Probably the thing that makes it most difficult, and maybe it's the most relevant to talk about, is that let's say you want to do a computation with a quantum computer, and you want to describe it by a certain number of particles, and you want to use those particles to do your quantum simulation. Then you need to be able to control those particles right, to manipulate them to do the computation you want. But if those particles interact with the environment, then part of the information that you wanted to control or manipulate will actually evolve and become connected to.

These other particles.

These other particles.

And that's the really tricky problem is how do I control tiny little quantum particles with my grubby little hands, so to speak. So I have to be able to send in these control signals to and manipulate these quantum particles, but I can't let in any other parts of the environment in the same time, and so it becomes a really hard problem to sort of shield the system you're trying to use to do this computation, but then also allow yourself these control knobs.

And that's the really tricky problem is how do I control tiny little quantum particles with my grubby little hands, so to speak. So I have to be able to send in these control signals to and manipulate these quantum particles, but I can't let in any other parts of the environment in the same time, and so it becomes a really hard problem to sort of shield the system you're trying to use to do this computation, but then also allow yourself these control knobs.

Is it like a question of purity to.

Is it like a question of purity to.

Some degree, yes, Like the properties electron have to be just that electron, and they interact with other things that you're not able to control, you lose the information.

Some degree, yes, Like the properties electron have to be just that electron, and they interact with other things that you're not able to control, you lose the information.

All right.

All right.

So the reason that quantum computers are so hard to make and run basically goes back to Schrodinger's cat. Might have heard of this analogy when people are talking about quantum things, And the idea is that if I take a cat and I put it inside a box, and I also put in the box a quantum particle that might kill the cat. Then when I close the box, eventually the cat becomes both alive and dead at the same time. And that's because when I close the box, the quantumness of that killer particle basically extends to the cat itself. Now, a quantum computer is basically like taking a whole bunch of those boxes with cats that are alive and dead at the same time, and it tries to do math with them. And because all those cats are in that magical quantum state of being two different things at the same time, alive and dead, then you can do some really powerful computations with them, like multiply a whole bunch of numbers all at the same time. But as soon as anyone takes a peek inside one of those boxes and the whole thing collapses. As soon as you open one box and you see whether the cat is alive or dead, then that box loses its quantum magic, and all the other boxes that are talking to it will also lose their quantum magic. So the reason you need to build giant refrigerators and keep these computers in an almost perfect vacuum with perfect coldness is to protect them from any random bit of motion or energy from essentially peeking inside your quantum boxes, because if that happens, the whole thing collapses and stops working. And this problem only gets worse as you make the computers bigger and more complicated. But people like Oscar are getting better and better at it. Well, that was great, that was awesome. I guess just the last question, what is the current state of the art in quantum computers?

So the reason that quantum computers are so hard to make and run basically goes back to Schrodinger's cat. Might have heard of this analogy when people are talking about quantum things, And the idea is that if I take a cat and I put it inside a box, and I also put in the box a quantum particle that might kill the cat. Then when I close the box, eventually the cat becomes both alive and dead at the same time. And that's because when I close the box, the quantumness of that killer particle basically extends to the cat itself. Now, a quantum computer is basically like taking a whole bunch of those boxes with cats that are alive and dead at the same time, and it tries to do math with them. And because all those cats are in that magical quantum state of being two different things at the same time, alive and dead, then you can do some really powerful computations with them, like multiply a whole bunch of numbers all at the same time. But as soon as anyone takes a peek inside one of those boxes and the whole thing collapses. As soon as you open one box and you see whether the cat is alive or dead, then that box loses its quantum magic, and all the other boxes that are talking to it will also lose their quantum magic. So the reason you need to build giant refrigerators and keep these computers in an almost perfect vacuum with perfect coldness is to protect them from any random bit of motion or energy from essentially peeking inside your quantum boxes, because if that happens, the whole thing collapses and stops working. And this problem only gets worse as you make the computers bigger and more complicated. But people like Oscar are getting better and better at it. Well, that was great, that was awesome. I guess just the last question, what is the current state of the art in quantum computers?

Yeah, so I think that if you can look at this on I would say three axis, so you can ask how many physical cubits can I make in.

Yeah, so I think that if you can look at this on I would say three axis, so you can ask how many physical cubits can I make in.

Control right now?

Control right now?

Right?

Right?

What's the highest number of somebody that has been So.

What's the highest number of somebody that has been So.

If you just said I just want to be to control this many cubits, it's a few hundred. And people have made systems of more than a few thousand, but maybe not controlled all of them simultaneously. But people have definitely made a few hundred and controlled them. So we're getting to that level. And you might say, well, okay, put that in context, and if we could control them with high enough fidelity and not make errors, we would be at the point where we could actually start to access and solve problems of practical utility better than we think other computers can, like we could answer some of these questions about how electrons interacted materials, like small toy problems, but still useful.

If you just said I just want to be to control this many cubits, it's a few hundred. And people have made systems of more than a few thousand, but maybe not controlled all of them simultaneously. But people have definitely made a few hundred and controlled them. So we're getting to that level. And you might say, well, okay, put that in context, and if we could control them with high enough fidelity and not make errors, we would be at the point where we could actually start to access and solve problems of practical utility better than we think other computers can, like we could answer some of these questions about how electrons interacted materials, like small toy problems, but still useful.

So like, if I have a thousand cubits working, yeah, what kinds of passwords can I break? Right now?

So like, if I have a thousand cubits working, yeah, what kinds of passwords can I break? Right now?

Yeah?

Yeah?

So, like the number of bits and an RSA key is like a few thousand, So if I had a few thousand cubits, I could crack RSA a.

So, like the number of bits and an RSA key is like a few thousand, So if I had a few thousand cubits, I could crack RSA a.

Few thousand, and we're at one thousand now. Yeah, so right now we can maybe crack simple passwords.

Few thousand, and we're at one thousand now. Yeah, so right now we can maybe crack simple passwords.

Like yeah, surely that's right, shorter short of ones that we can already do classically, So probably not useful, but we're within striking. But the bigger problem is that we can't do those calculations because our calculations are too air prone.