Speaker 1: So you know how sometimes in physics there's a word,
Speaker 1: and this word for people it's like magic. It means
Speaker 1: like a big leap forward. It's like a huge transformation,
Speaker 1: you mean, like dimensions, dimension is the worst, absolutely, and
Speaker 1: stuff like that. And the one I'm thinking of in
Speaker 1: particular is the word quantum. Quantum mechanics obviously a huge
Speaker 1: transformation the way we think about the world that it
Speaker 1: also seems to be a transformation and everything like you
Speaker 1: can find like quantum massage, and you know, there's that
Speaker 1: whole television show Quantum Leap, and like all this stuff
Speaker 1: has nothing to do with quantum mechanics at all. It's
Speaker 1: just the word quantum seems to represent some sort of
Speaker 1: high tech, next generation high tech fanciness. You know, sometimes
Speaker 1: it really does represent a transformative leap. Sometimes there really
Speaker 1: is an opportunity to convert a normal version of something
Speaker 1: into the quantum version and then take a huge step forward.
Speaker 1: And so that's what we wanted to talk about today.
Speaker 1: After my quantum massage hold on him and I'm Daniel
Speaker 1: and this is our podcast. Daniel and Jorge explained the
Speaker 1: universe in which we take the whole universe and chop
Speaker 1: it up in the little pieces, turn each of them
Speaker 1: into a quantum of understanding and download it into your
Speaker 1: brain and in which you feel like you understand and
Speaker 1: not understand at the same time. No, we're going for
Speaker 1: a hundred understanding. We don't want to be one of
Speaker 1: those podcasts where you feel like, oh, I heard a
Speaker 1: lot of smart people talking about it, but I didn't
Speaker 1: really get it right. Yeah. Yeah, because in this podcast
Speaker 1: you only listen to one intelligent person, Joe and I
Speaker 1: together making one intelligent person. We won't say which fraction
Speaker 1: of each, but together we are one smart guy. We
Speaker 1: are quantum entangled in our intelligence. That's right. That's right,
Speaker 1: And this is just the latest in our projects together.
Speaker 1: We also wrote a book called We Have No Idea,
Speaker 1: A Guide the Unknown Universe, where we explore all the
Speaker 1: big questions in the universe, what doesn't physics know yet
Speaker 1: and what could it mean for humanity? And if you
Speaker 1: search online on YouTube, you can also find a couple
Speaker 1: of the videos that we've made together about the Higgs boson,
Speaker 1: about dark matter, about gravitational waves. So check this out. Yeah,
Speaker 1: so today we wanted to talk about quantum computers because
Speaker 1: we feel like it's a word that's bandied around, and
Speaker 1: we wanted to make sure everybody understood what it actually means.
Speaker 1: Think about whether you know what a quantum computer is. So,
Speaker 1: as usual, I went out and I asked ten random
Speaker 1: people on the u c I campus if they knew
Speaker 1: what a quantum computer was and how it works. And remember,
Speaker 1: some of these people are computer science undergraduates, so they
Speaker 1: really should know. Here's what they had to say. Nope, nope,
Speaker 1: you never heard of a quantum computer? All right, cool,
Speaker 1: I have no idea. Have you heard of the quantum computer?
Speaker 1: This is the first time that I'm hearing it right now.
Speaker 1: I'm not sure about how does it work, but I
Speaker 1: know that it has four men bits or alphabet and
Speaker 1: it is said to revolutionalize the computer science. I don't
Speaker 1: know about a quantum computer, but you've heard of them. Um.
Speaker 1: I've heard the term, but I don't know much else
Speaker 1: about it other than that. Alright, So not a not
Speaker 1: an impressive performance here by uc I Underground. That's right. Well, hey,
Speaker 1: some of them understood it, right, at least most of
Speaker 1: them have heard of it. The one guy like heard
Speaker 1: about quantum computers. The moment I said the phrase, it
Speaker 1: exploded in his brain. Like, what, I've never heard of
Speaker 1: that until you mentioned it. I've never heard those two
Speaker 1: words together. You've probably spend the next six hours googling
Speaker 1: and reading about it. And maybe he's the next future
Speaker 1: quantum computing genius. We have changed the course of human
Speaker 1: history through this podcast or oh my god, it's possible.
Speaker 1: But most people seem to have very little understanding of
Speaker 1: what a quantum computer is. Um though, you know, somebody
Speaker 1: out there had had some idea at least, so we
Speaker 1: feel like this is a good topic for a podcast.
Speaker 1: Let's clear out the weeds of everybody's understanding and make
Speaker 1: sure everybody knows what we're talking about when we say
Speaker 1: quantum computer. I mean everyone has heard of a computer,
Speaker 1: but a quantum computer. That just sounds interesting, Right, What
Speaker 1: do you what do you what did you think of
Speaker 1: the first time you heard quantum computer? Do you think
Speaker 1: like a tiny computer the size of an atom? What
Speaker 1: did I think? I thought that it was? I think
Speaker 1: I just had that good reaction. Also, it's like a
Speaker 1: like a super new magic computer, right, Like I want
Speaker 1: a quantum Ferrari. We just said for my quantum mortgage
Speaker 1: to be paid first. I love how the word quantum
Speaker 1: is just like taken on this magical mystical power, you know,
Speaker 1: and it's not bad. There's like no nuance to quantum
Speaker 1: that's bad. It's not like dark or dangerous. It's just
Speaker 1: like the new, fancy, glittery, shiny version of something. The
Speaker 1: weird thing is is that it's not a new word, right, Like,
Speaker 1: it's a word that's been around for a hundred years nearly, right, Well,
Speaker 1: it's been around for a long time and it's been
Speaker 1: applied to this kind of thing for about a hundred years. Yeah,
Speaker 1: quantum mechanics is almost a hundred years old. To the idea,
Speaker 1: the very basic ideas of quantum mechanics, you know, that
Speaker 1: the universe is chopped into pieces and not continuous. That's
Speaker 1: not a very new idea, right, Well, let's break it down.
Speaker 1: What does it mean when you say the word quantum,
Speaker 1: like quantum physics or quantum particles? You know, what does
Speaker 1: it mean? Well, the word basically just means portion or
Speaker 1: packet or unit, you know, it's like a quantity, like, yeah,
Speaker 1: quant quantity, quantum is that where it comes from? Yeah,
Speaker 1: it's connected. Why I think Jorge just had a realization
Speaker 1: and live right there on the podcast. Um, Yes, it's
Speaker 1: related to quantities, right. It says things that are are
Speaker 1: quantized are things that are made out of little atomic pieces,
Speaker 1: things that can't be broken into smaller pieces. Right, So
Speaker 1: like our money is quantized. We don't have money less
Speaker 1: than a penny, right, you can't spend less than a penny.
Speaker 1: That's the basic unit. Everything is built out of that.
Speaker 1: And it's relevant to physics because it turns out the
Speaker 1: universe is quantized, like particles are made out of smaller particles.
Speaker 1: You can't have like half a particle or three quarter
Speaker 1: of a particle. And energy levels are quantized, you know,
Speaker 1: the way electrons move around in nucleus. They can't just
Speaker 1: have like any arbitrary amount of energy, just like a
Speaker 1: ladder of energy levels. They can be on and they
Speaker 1: can't be in between those steps. But it kind of
Speaker 1: means more than just the idea of chopping things up
Speaker 1: into a little bit. It's really more about what the
Speaker 1: world is like when you get down to those little
Speaker 1: little little bits. Quantum physics means the physics of those
Speaker 1: little little little particles, which is very different than the
Speaker 1: physics of like, you know, a basketball or a baseball
Speaker 1: that's right. Quantum. That's what quantum means. It's a little
Speaker 1: bit bits and quantum mechanics or quantum physics that deals
Speaker 1: with how those things interact with each other. And it
Speaker 1: turns out that those little tiny bits of the universe
Speaker 1: interact in ways that are very unfamiliar to us. There's
Speaker 1: very little intuitive understanding we can grasp the way those
Speaker 1: things work because they follow very different rules than the
Speaker 1: things than baseballs and basketballs follow. They follow more probabilistic rules,
Speaker 1: and and your intuition that you developed through observing the
Speaker 1: way baseballs and basketballs moved through the air doesn't work
Speaker 1: when you're talking about electrons or other little quantum particles
Speaker 1: because they follow different rules. Yeah, and those different rules
Speaker 1: lead to a very different kind of logic. You see,
Speaker 1: in normal logic, you can say something like a switch
Speaker 1: is either on or off, but not both, right, But
Speaker 1: in quantum logic it's different, which is why quantum computing
Speaker 1: turns out to also be different. Yeah, they don't behave
Speaker 1: like they do the big things behave, right, Like if
Speaker 1: you had a baseball the size of a quantum particle,
Speaker 1: you can just bounce it off of a wall, That's right.
Speaker 1: And the most important feature of these little quantum bits,
Speaker 1: and the one that's gonna be relevant for quantum mechanics,
Speaker 1: is that we don't know everything about them. Like a baseball,
Speaker 1: you know everything you need to know. You know it's
Speaker 1: direction and you know it's velocity. From that, you can
Speaker 1: predict its future. If you know where it is and
Speaker 1: where it's going, you know where it's going to be. Right.
Speaker 1: For a quantum particle, like an electron, you can't observe
Speaker 1: it directly, and so there's some uncertainty about where it is,
Speaker 1: which means that it can be like here or it
Speaker 1: can be there. But the crucial thing about a quantum
Speaker 1: particle is it's not actually in one place or the other,
Speaker 1: and you just don't know it. It has a probability
Speaker 1: to be in both places. Our lack of knowledge about
Speaker 1: it reflects the fact that it's location is not actually determined.
Speaker 1: It's like it could be over here and it could
Speaker 1: be over there, which means it's a little bit of both.
Speaker 1: And that's what I mean when I say the act
Speaker 1: in ways that are different from the ways that are
Speaker 1: normal things interact. You know, a baseball is either here
Speaker 1: or it's there, right, But when you get down to
Speaker 1: that size, it doesn't look like like an electron doesn't
Speaker 1: look like a little tiny baseball. Nobody knows what an
Speaker 1: electron looks like. Yeah, like when you try to zoom
Speaker 1: in and you zoom in, it just becomes fuzzy, right,
Speaker 1: like you see this little fuzziness right. Well, that's a
Speaker 1: whole other funny question, like what would an electron look like?
Speaker 1: Because an electron is has zero size, right, zero volume,
Speaker 1: and so it doesn't really look like anything. But about
Speaker 1: the electrons fuzziness, we say the electron has a probability
Speaker 1: to be in a few different places. That's the fuzziness.
Speaker 1: But it's not determined before you ask. But when you
Speaker 1: want to interact with the electron, like if you want
Speaker 1: to measure where it is, then those probabilities collapse into
Speaker 1: a specific outcome. We call that collapsing the wave function
Speaker 1: because remember electrons are particles, but they're controlled by wave equations,
Speaker 1: which determine the probability of being in various places, kind
Speaker 1: of like if you're not looking at it, it's sort
Speaker 1: of like a cloud almost, and then when you look
Speaker 1: at it, then boom, it's a little point. That's right,
Speaker 1: And this is the deep question of quantum mechanics that
Speaker 1: that a lot of people do and understand. Most people
Speaker 1: don't understand. I think maybe everybody doesn't understand. How does
Speaker 1: that make any sense? Right? How does it make sense
Speaker 1: that something can be in both places at once until
Speaker 1: you ask look at it? How does it make sense
Speaker 1: that you asking changes where it's going to be? Right?
Speaker 1: It's it's it's a situation, and that's all. There's a
Speaker 1: huge philosophical debate about that. You know, is it the
Speaker 1: asking that makes a decide where it's it going to be?
Speaker 1: Or does the universe split into two options where you know,
Speaker 1: on one hand it's on the left and then the
Speaker 1: other universe it's on the right. And different people argue
Speaker 1: about this stuff for for decades and decades. So it's
Speaker 1: certainly not something we can address in twenty minutes on
Speaker 1: a podcast. But the thing you need to know to
Speaker 1: understand quantum mechanics is that there's a probability for it
Speaker 1: to be in one place or the other, and that
Speaker 1: both probabilities exist simultaneously. So if I'm not if I'm
Speaker 1: not looking at the electron, it looks like a little
Speaker 1: fuzzy cloud and you're saying that cloud is it's it's
Speaker 1: kind of like it's in all those places at the
Speaker 1: same time with a certain probability. Yeah, I think the
Speaker 1: most correct statement would say it has a probability to
Speaker 1: be in all of those places. To say it actually
Speaker 1: is in all those places, I mean you don't. It's
Speaker 1: not actually anywhere. It just has a probability to be
Speaker 1: those things. It's like the answer is not determined or known.
Speaker 1: It's not like God has it written down on a
Speaker 1: golden tablet somewhere. We just don't know. It's not actually anywhere.
Speaker 1: It just has a probability to be this or that.
Speaker 1: It's like it's like a die you haven't ruled yet.
Speaker 1: It's not like it already is a four and you
Speaker 1: just haven't looked yet. You haven't rolled the die, so
Speaker 1: you don't There isn't an answer. The same way the
Speaker 1: electron has a probability distribution to be in various situations,
Speaker 1: but until you measure it, it's not in all of
Speaker 1: those at the same time. It just has a probability
Speaker 1: to be in those things. Man, So you're saying all
Speaker 1: of us, all of our particles are if you get
Speaker 1: down to that level, they're all unthrown die, yes, exactly,
Speaker 1: until you interact with them and forces the universe to
Speaker 1: throw the die. And that's one of the deep questions
Speaker 1: about about econom mechanics, is like where's that die? Who's
Speaker 1: doing those random number process you know? So when Einstein
Speaker 1: famously said God doesn't play dice, it's kind of true.
Speaker 1: It's like, really, things are all just unthrown dice. Yeah,
Speaker 1: he didn't like that description of it at all. He
Speaker 1: really believed that the dice was already thrown. We just
Speaker 1: didn't know the answer, right, That's a big difference. That's
Speaker 1: a big difference. And then eventually they proved that actually
Speaker 1: the dice is not yet thrown until you ask the question.
Speaker 1: And that's a whole other podcast. We can talk about
Speaker 1: how they proved that. It's called the bell inequality, and
Speaker 1: it's a whole other topic we can get into. But
Speaker 1: I think for today's episode, people just need to understand
Speaker 1: that a quantum particle can be different from a classical particle,
Speaker 1: from like a thing you're you're understand because it can
Speaker 1: be kind of a probability to be in two different
Speaker 1: situations at the same time. Okay, So that's that's what
Speaker 1: quantum means. And now let's get into quantum computers. But
Speaker 1: first let's take a break, all right. So that's what
Speaker 1: quantum means. It's like the how the world behaves when
Speaker 1: you get down to those little tiny pits of the universe,
Speaker 1: which is totally different and kind of fuzzy and probabilistic. Um.
Speaker 1: So now let's combined it with the word everyone knows,
Speaker 1: which is a computer. So what does it mean to
Speaker 1: like have a quantum computer. Yeah, so the idea there is,
Speaker 1: let's build a computer. Let's build out of pieces that
Speaker 1: can do these weird things, because then maybe you can
Speaker 1: solve problems that are otherwise hard. I mean, I think
Speaker 1: it's also important to think about how a normal computer works,
Speaker 1: and like what does it mean to say a computer
Speaker 1: before we think about what is a quantum computer um?
Speaker 1: And for those of you out there listening, you probably
Speaker 1: know what a computer is. You have one in your
Speaker 1: in your office or whatever. You're banging on it right
Speaker 1: you download stuff and play Mario card or whatever. But
Speaker 1: what it's doing on the inside is really is that
Speaker 1: it's doing calculations. Right, a program on your computer or
Speaker 1: something that does a calculation, Maybe that calculation is how
Speaker 1: do I draw Mario card on the screen? Or you know,
Speaker 1: how do I predict this the trajectory of this cannonball
Speaker 1: that I want to fire at my opponent's castle or whatever.
Speaker 1: In the end, it's doing a calculation. And the way
Speaker 1: it does that calculation is that it represents the problem
Speaker 1: that needs to be solved in terms of a bunch
Speaker 1: of numbers, because all the computer really, in the end
Speaker 1: is doing is manipulating numbers. I mean the memory and
Speaker 1: your computer is a bunch of ones and zeros. That's
Speaker 1: what we call bits, and those represent a number. And
Speaker 1: a computer is useful when you can take a problem
Speaker 1: you want to solve and represent it in a way
Speaker 1: that the computer knows how to solve it right. Right, So,
Speaker 1: for example, how do I hit my baseball in a
Speaker 1: way that goes over the fence? What angle is the
Speaker 1: best angle to do that? Right? Do? You want to
Speaker 1: solve that problem? But you first have to break it
Speaker 1: down into math and then have your computer basically act
Speaker 1: as a calculator and crunch those math equations. And the
Speaker 1: kind of math you use to break it down depends
Speaker 1: on the kind of computer you have and the kind
Speaker 1: of calculations that computer can do. So the kind of
Speaker 1: computers we use, classical computers have ones in zeros, and
Speaker 1: all they can do are a few basic logical operations
Speaker 1: on those ones and zeros they can do and they
Speaker 1: can do or they can do x or or nand
Speaker 1: and you can build those up to do all sorts
Speaker 1: of more complicated things like addition or subtraction or Mario
Speaker 1: Kard and other video games. Right, And the way it
Speaker 1: does that you're saying, is that it takes the problem,
Speaker 1: you know, whereas Mario and Mario card or how much
Speaker 1: is tu plus two and then breaks it down into bits,
Speaker 1: which is are which are ones and zeros. So everything that,
Speaker 1: like most of our language, all the math that we
Speaker 1: know about, all that can be essentially eventually breaking down
Speaker 1: into ones and zeros. That's right, and we'll see later.
Speaker 1: The quantum computers don't use ones and zeros, and they
Speaker 1: have a different kind of logic, so they can solve
Speaker 1: different kinds of problems. And in the end, it's all
Speaker 1: about efficiency. Which kind of computer is faster at which
Speaker 1: kind of problem running Mario cards or breaking into the
Speaker 1: n s A does it take one second or does
Speaker 1: it take a build in years? Well, let's talk a
Speaker 1: bit about why you want to break it down into
Speaker 1: ones and zeros, right, Like, why is why is that important?
Speaker 1: Because once you break it down to ones and zeros,
Speaker 1: then even like a simple computer can then add and
Speaker 1: subtract those, Right Like, if you can break the whole
Speaker 1: world into ones and zeros and everything into simple operations
Speaker 1: like plus or minus, then you can have a machine
Speaker 1: basically do it. Yeah, you can do simple logic operations
Speaker 1: on ones and zeros, and there's a theorem that shows
Speaker 1: that you can combine those to do any logical operation.
Speaker 1: So if you combine enough of those together, you can
Speaker 1: have any operation on your inputs. That doesn't mean necessarily
Speaker 1: the best way to do any problem. Like you might say, hey,
Speaker 1: I want to know where this baseball is going to go.
Speaker 1: So one way to do that is build a computer,
Speaker 1: have inside the computer a perfect model of how the
Speaker 1: baseball works, and do the calculation. Another way to do
Speaker 1: that is just hit the baseball. Right from that perspective,
Speaker 1: like a baseball is a computer that calculates one thing,
Speaker 1: how far does this base ball go? Right. It's very powerful,
Speaker 1: it's very fast, but it only does that one thing.
Speaker 1: The advantage of a classical computer with ones and zeros
Speaker 1: is that it can solve lots of different kinds of problems.
Speaker 1: They can do your baseball problem, and they can do
Speaker 1: Mario Kart right, Okay, So that's the basis of regular computers,
Speaker 1: Like even the computer and the phone that people are
Speaker 1: listening to this podcast on. It's taking our voices, breaking
Speaker 1: them down to one and zeros, chopping those up, mixing
Speaker 1: them up, and then basically recreating our voices and flappy bird. Right,
Speaker 1: that's right exactly. And so what is a quantum computer. Well,
Speaker 1: a quantum computer is a computer built out of different
Speaker 1: little pieces. Right. Whereas the normal computer uses ones and zeros,
Speaker 1: a quantum computer uses quantum mechanical objects that have different properties.
Speaker 1: They can be zero, they can be one, or they
Speaker 1: can be some combination of zero and one. The way
Speaker 1: a quantum particle is like, maybe it's here, maybe it's there.
Speaker 1: A quantum bit, what we call a cube bit, is
Speaker 1: maybe zero, maybe one, has a probability be zero and
Speaker 1: a probability to be one. And again it's not secretly
Speaker 1: zero and secretly one. Like a dice you've already rolled
Speaker 1: and you just haven't looked at. It's not determined. It's
Speaker 1: some combination of zero and some combination of Wow. I see,
Speaker 1: what if he had a computer that was fundamental little
Speaker 1: processing unit is not just black and white, but maybe
Speaker 1: like some something in between the shades of gray, shades
Speaker 1: of great, Like what would happen if you add and
Speaker 1: mix those up and try to make calculations with things
Speaker 1: that can be not just ones and zeros. Yeah, And
Speaker 1: so what happens is you get a very different kind
Speaker 1: of computer, one that's much better at things that classical
Speaker 1: computers find difficult, but also is worse at some things
Speaker 1: that classical computers find very easy. Like what, Yeah, just
Speaker 1: the way, like a baseball is a good computer for
Speaker 1: calculating what a baseball does, it's not very good at
Speaker 1: organizing your recipes or doing Mario Kart, right. A quantum
Speaker 1: computer is built differently, it's but it still runs in
Speaker 1: the physical universe, you know all the things. These computers
Speaker 1: are just ways to manipulate physical objects to represent calculations
Speaker 1: that we want done. That's what a computer is, right,
Speaker 1: And sometimes the classical computer is really good at that.
Speaker 1: A quantum computer, because it's made out of different things,
Speaker 1: is good at at different kind of calculations. It's like
Speaker 1: do you want to build your house out of wood
Speaker 1: or out of brick? Well, you know wood is good
Speaker 1: for some things and brick is good for other things.
Speaker 1: You get a pretty different kind of house. Um, so
Speaker 1: they're pretty different, but you know they're related, but they
Speaker 1: have different strengths, and those strengths and weaknesses come from
Speaker 1: the essential differences in how those bits work. Okay, so
Speaker 1: let's get into some of these differences from where they
Speaker 1: come from. So, like, what's happening now instead of when
Speaker 1: I'm mixing these cube bits that's what they're called, right,
Speaker 1: the quantum bits, they're called cube bids. Yeah, Um, so
Speaker 1: what's happened? What's happening when I mix them? Like if
Speaker 1: I do a calculation with these fuzzy bits. Right, So
Speaker 1: there's really two things you have to understand about how
Speaker 1: quantum calculations work. First of all, is that you when
Speaker 1: you have two cube bits, they're not independent. It't Okay,
Speaker 1: you have two bits and a computer, then they can
Speaker 1: have four different states zero zero, zero, one, one zero
Speaker 1: or one one. Right, So two bits means two to
Speaker 1: the end different states. But you really just need two
Speaker 1: numbers to specify that, right, you need the first number
Speaker 1: in the second number totally specifies the configuration. So it's
Speaker 1: really just two bits means two pieces of information for
Speaker 1: a classical computer. That's because those two bits are totally independent.
Speaker 1: For a quantum computer, the cubits are not independent. They're entangled, okay,
Speaker 1: so they're connected to each other. And so you can
Speaker 1: have different states. You can have zero zero, you can
Speaker 1: have one one. You can have some mixture of one
Speaker 1: zero and zero one. You can have other mixtures of zero, zero,
Speaker 1: zero one. There's four combinations there, and what you get
Speaker 1: are you need four piece of information to specify which
Speaker 1: state you're in. You have simultaneously some probability to being
Speaker 1: zero zero, some probability to being zero one, some probability
Speaker 1: being one zero, and some probability being one one. So
Speaker 1: two cubits means four pieces of information needed to store
Speaker 1: the configuration. So two to the end pieces of information
Speaker 1: from two cubits, right, Whereas in a classical computer, if
Speaker 1: there are end bits, there are two to the end
Speaker 1: different states, but you only need end pieces of information
Speaker 1: to specify the state. So if there are two bits, right,
Speaker 1: then there are four different states that can be in,
Speaker 1: but you only need two pieces of information to tell
Speaker 1: you exactly which state it's in, and a quantum computer
Speaker 1: with two cubits you need to specify the probability of
Speaker 1: each of the two to the end different states it
Speaker 1: can be in at the same time, which means you
Speaker 1: need four pieces of information to totally kneel down the
Speaker 1: state of a two cubit quantum computer, right, because you're
Speaker 1: mixing two things that are that could be a wide
Speaker 1: range of things, right, that's right, because you not just
Speaker 1: have the things, you have the relationships between them. Right,
Speaker 1: So as the number of things grows you have like
Speaker 1: thirty cubits, then you not just have is the state
Speaker 1: of this bit? You have the state what is the
Speaker 1: relative state of these two things? How closely connected are they?
Speaker 1: So if you have, for example, thirty cubits, you need
Speaker 1: to to the thirty numbers to specify the state of
Speaker 1: that quantum system. And that that's very powerful because you
Speaker 1: know how many particles are there in the universe. There's
Speaker 1: like two to the three hundred particles in the universe.
Speaker 1: So a quantum computer that had three hundred cubits in it, right,
Speaker 1: it has as much information as like all the numbers
Speaker 1: of the particles in the entire universe. Boomation. Wait, that
Speaker 1: just means that a simple operation in the quantum computer
Speaker 1: can represent a much bigger, sort of richer result. Is
Speaker 1: that kind of what it means? Like, there's two different
Speaker 1: there's two pieces to a computer. There's the information in it,
Speaker 1: on the operations you can do right right now, we're
Speaker 1: just talking about the information in it. But yes, a
Speaker 1: smaller quantum computer can represent much more information with a
Speaker 1: smaller number of bits. I see. So like three hundred
Speaker 1: regular bids from a regular computer can maybe store the
Speaker 1: yes or no voting information from three hundred people, right, yeah,
Speaker 1: whereas three hundred quantum bids can store the information from
Speaker 1: basically the entire universe. Now, let's be careful not to
Speaker 1: oversell it. It takes two to the three hundred numbers
Speaker 1: to specify the state of three d cubits, that's right,
Speaker 1: But that doesn't mean that a three hundred cubic computer
Speaker 1: can usefully store two to the three hundred pieces of information, because,
Speaker 1: as we will talk about later, cubits have a very
Speaker 1: rich internal state, but the information is not as accessible
Speaker 1: as it is with classical bits. Okay, like with the
Speaker 1: electron that has lots of different probabilities. You only measure
Speaker 1: it in one of them. So if all the particles
Speaker 1: in the universe got together to vote on something, you'd
Speaker 1: still need a pretty big computer. Who wants to exist
Speaker 1: crazy he thinks Jorge should have another banana. Yes or no,
Speaker 1: that's just the state of the system. Right. Then there's
Speaker 1: the operation, and there's a there's another sort of magical
Speaker 1: thing that happens. Oh, I shouldn't say magic, because none
Speaker 1: of it's magical. It seems like magic because it's so weird,
Speaker 1: but it's it's actually physics, right, um, And that's what
Speaker 1: happens when you do in operation. You know, in a
Speaker 1: normal computer, your operations like math. I'm gonna add one
Speaker 1: and one and see what it happens when I get
Speaker 1: to what happens when you do a quantum calculation. Remember
Speaker 1: that the states can be in the superposition of different states, right,
Speaker 1: It's like in state zero and sixty percent in state one.
Speaker 1: Like it can be white in seventy percent black. That's
Speaker 1: like one cuban right, right. And it's not that it
Speaker 1: has the shade of gray which is white and black.
Speaker 1: It's has a probability to be white. And a probability
Speaker 1: to be black. If you look at it, you can
Speaker 1: only see white or black. You'll never see gray. Oh
Speaker 1: I see. But seventy of the time you'll see it
Speaker 1: black and you'll see it as white exactly. Oh I see.
Speaker 1: So it's not gray, it's just as a probability of
Speaker 1: being black or white. That's right. When you do an operation,
Speaker 1: you don't it doesn't collapse to black or white and
Speaker 1: then do the operation. It does the operations on the
Speaker 1: probabilities themselves. Okay, so it have you have the thirty
Speaker 1: percent of zero and thirty percent of one, or thirty
Speaker 1: percent of white and black or whatever, and you do
Speaker 1: the operation. It does the operation on the zero and
Speaker 1: it does the operation on the one at the same time.
Speaker 1: So it keeps both probabilities and it evolves them forward
Speaker 1: in time using quantum mechanics. So it's like doing two
Speaker 1: operations at once. Is it kind of like as we
Speaker 1: were saying earlier, a quantum bid is kind of like
Speaker 1: an unthrown dice, right, So if you it's like, what
Speaker 1: happens if I multiply this die that I haven't thrown
Speaker 1: times this died that I also haven't thrown what's the
Speaker 1: result exactly, And it needs to consider, well, you know
Speaker 1: it might be too and so what would happen if
Speaker 1: it were too okay? And what would happen if it
Speaker 1: was four? And what would happen if it were six?
Speaker 1: And it propagates all those forward simultaneously because the quantum
Speaker 1: state reflects all those probabilities, and the quantum operation moves
Speaker 1: all those operations, all those probabilities forward in time and
Speaker 1: effect doing all of those in parallel. So you have
Speaker 1: a massive amount of information density, plus you have massive
Speaker 1: parallelism to do these conversations. It keeps all of those
Speaker 1: possibilities inside of this new combination of information, like it's
Speaker 1: like it has all the possibilities thwart into this little
Speaker 1: imaginary multiplication. That's right. And then the new state is
Speaker 1: some different arrangement of those possibilities, right, but it reflects
Speaker 1: all the probabilities in the previous state. Now here's an
Speaker 1: important place that a lot of people misunderstanding quantum computers.
Speaker 1: A lot of people say, oh, quantum computers are super
Speaker 1: powerful because they're basically infinitely parallel. You can do like
Speaker 1: a million calculations in parallel because of quantum mechanics. Meaning
Speaker 1: it keeps all these probabilities sort of in its head. Yeah,
Speaker 1: and it sort of seems like magic, like you know,
Speaker 1: I can try um, I can break passwords, because I
Speaker 1: can try millions of things all at the same time. Well,
Speaker 1: that's not exactly true. I mean there's some truth to it,
Speaker 1: because there is parallelism in the quantum world because you're
Speaker 1: keeping all these probabilities intact and you're operating on them,
Speaker 1: and you're moving them all fullward simultaneously. The problem is
Speaker 1: when you get the answer. Okay, you want to say, okay,
Speaker 1: I have my quantum state, I did my calculation. Now
Speaker 1: I want the answer, right, how do you measure that?
Speaker 1: When when you measure it, you're gonna get your black
Speaker 1: or your white. You're gonna get your zero or one.
Speaker 1: You don't get all the information. You don't get all
Speaker 1: the probabilities. You just get one answer. You roll the dice,
Speaker 1: you get your four or you get your six, and
Speaker 1: you look at it. You just get a number. You
Speaker 1: just get a number. Yeah, And so a lot of
Speaker 1: that information is lost, right, huge amounts of that information
Speaker 1: is lost when you want to get the output from
Speaker 1: the quantum computer. And so that's why it's not really
Speaker 1: fair to say that it's like this huge massive parallelism.
Speaker 1: There is some parallelism there, and you can't exploit it
Speaker 1: to do certain kinds of calculations, but in the end,
Speaker 1: most of the information is thrown away when you get
Speaker 1: the answer. I see, it's a much harder problem than
Speaker 1: you think. Kind of yeah, exactly, And so we've built
Speaker 1: this new thing. It's a bunch of um, you know,
Speaker 1: states that can be black or white, and they're all
Speaker 1: entangled or whatever. And then you can ask, can I
Speaker 1: use this to do anything? Can I represents some calculation
Speaker 1: I have in a way that this physical thing I built,
Speaker 1: this entangled combination of quantum states, can effectively solve my problem,
Speaker 1: right the way classical computer can by representing in terms
Speaker 1: of math and zeros and ones or baseball, can solve
Speaker 1: that one single problem. Right, Can a quantum computer solve
Speaker 1: useful problems? Um? That's the next question. I see. Well,
Speaker 1: let's um, let's get into that. But let's take a
Speaker 1: quick break. Okay, So let's say that I build a
Speaker 1: quantum computer, and you're saying it's not gonna be great
Speaker 1: for playing Mario Kart unless you're playing quantum Mario card
Speaker 1: quantum Marit card is awesome, Yeah, because you're both like
Speaker 1: a dead and alive at the same time. Right, But
Speaker 1: it wouldn't be useful for like, you know, playing flabby
Speaker 1: Bird on your phone or surfing Facebook. So what what
Speaker 1: would it be good of? What are people excited about
Speaker 1: making quantum computers? Yeah, well, it took a while for
Speaker 1: people to figure this out. You know, people thought about
Speaker 1: the idea of quantum computers a few decades ago, like, okay, um,
Speaker 1: the you know, the world is built in a quantum way,
Speaker 1: maybe our computer should be quantum. And then it took
Speaker 1: a few decades for people to come up with ideas
Speaker 1: for how to actually use them. Like, let me take
Speaker 1: a problem I have mapping into something that can be
Speaker 1: represented with a quantum state, so that when I do
Speaker 1: this experiment on it, do these operations on it, the
Speaker 1: output of that experiment is basically answered to my question.
Speaker 1: Remember that's sort of what we're thinking of as it
Speaker 1: as a computer, right, because you can't just pretend to
Speaker 1: be making a quantum computer. You actually have to build
Speaker 1: it out of quantum things, things that are quantum, like
Speaker 1: you know what I mean, Like I can I can't
Speaker 1: just like add all these probabilities in my on my
Speaker 1: regular computer, Like the computer itself has to be made
Speaker 1: out of quantum things, right, Well, you know everything in
Speaker 1: the universe is made out of quantum things, right, so
Speaker 1: in that sense, you are a quantum computer. Or hey,
Speaker 1: that's right, Yeah, I am stacular um. And so one
Speaker 1: of the first things that people figured out was that
Speaker 1: there's an algorithm you can write down for factorizing big
Speaker 1: integers that says, take an integer and break it into
Speaker 1: its factors. You know, like fifteen is five times three.
Speaker 1: That's obvious, but what if you had a really big number.
Speaker 1: It's hard to necessarily know how to break down you know,
Speaker 1: one to four, seven, eight, ten into all of its factors.
Speaker 1: It's a hard, hard thing. It takes a while to do.
Speaker 1: You mean, like thirty can be five times six, where
Speaker 1: it can be three times ten, right, yeah, Well you
Speaker 1: want to break it down to all of its fundamental factors,
Speaker 1: and so thirty is two times three times five. Right,
Speaker 1: there's one unique set of factors for every integer um
Speaker 1: and that's not easy to do, right for big numbers,
Speaker 1: it could take a while because you basically just have
Speaker 1: to check them. And this some slightly more clever algorithms
Speaker 1: using normal computers. But normal computers it takes a long
Speaker 1: time for them to do this because they have to
Speaker 1: cycle through all the different possible You mean, like if
Speaker 1: I told you, like million, three hundred four thousand, seven
Speaker 1: dred and ninety nine, tell me all the numbers that
Speaker 1: can multiply into that number exactly, that would be a
Speaker 1: hard problem. May be a hard problem for me, and
Speaker 1: uh a slow problem for a classical computer. But there
Speaker 1: was a guy who figured out how to write an
Speaker 1: algorithm to use these quantum states how to represent that
Speaker 1: problem on a quantum computer, right, so that you can
Speaker 1: manipulate that computer and out out get the answer. And
Speaker 1: the way he did it, the algorithm that he came
Speaker 1: up with is much much faster on a quantum computer
Speaker 1: than on a normal computer, because in a sense, it's
Speaker 1: using the parallelism. It's like, let me represent all this number,
Speaker 1: how to build this number in lots of different ways
Speaker 1: and then push all those forwards simultaneously, right, And so
Speaker 1: he came up with an algorithm to do this. And
Speaker 1: this is a big deal because the fact that this
Speaker 1: is really hard for normal computers is the basis of
Speaker 1: a lot of modern cryptography, meaning like how passwords are encoded,
Speaker 1: that they use this idea of factoring large numbers. That's right.
Speaker 1: If you can instantly factorize a large number, then you
Speaker 1: can break a lot of modern cryptography. You can get
Speaker 1: into the Department of Defense and the I R. S
Speaker 1: and all that stuff, because all of those things, their cryptography,
Speaker 1: their their protection, their their cyber protection, assumes that it
Speaker 1: would take a long time to factorize a large number.
Speaker 1: Cryptography is based on the idea that let's find problems
Speaker 1: that are hard to solve but easy to check, right, Like,
Speaker 1: if you give me a big number and you asked
Speaker 1: me to find the factors, it might be take me
Speaker 1: a long time to find them, but once I had them,
Speaker 1: I could verify very quickly that they were correct. It
Speaker 1: just had to together, do I get the right answer,
Speaker 1: Like it's hard to get two times three times five
Speaker 1: from thirty, but it's easy to verify that two times
Speaker 1: street terms five is equal to yeah, exactly. And so
Speaker 1: if you can find a faster way to do these things,
Speaker 1: then you break this assumption that's in most modern cryptography.
Speaker 1: Not all, but most modern cryptography is based on the
Speaker 1: idea that these things are hard to find but easy
Speaker 1: to check. So quantum computers in theory can do this
Speaker 1: much much faster because of the way they're constructed. So again,
Speaker 1: they're better at some problems, like specialized problems, not necessarily
Speaker 1: better at everything though, right, not that I would ever
Speaker 1: have any need to break into the I R S
Speaker 1: or anything like that. Not it's clear in case there's
Speaker 1: any auditors listening here. But so how far away are
Speaker 1: we from getting there? Like, what's the current state of
Speaker 1: the art in terms of making quantum computers. We have
Speaker 1: quantum computers. People have built cubits, individual ones, and they
Speaker 1: built sets of cubits together. Um, you know, they're up
Speaker 1: to probably by the time this podcast comes out, of
Speaker 1: the numbers will be irrelevant, but you know, they're ten
Speaker 1: cubic computers out there, fifteen cubic computers. There are even
Speaker 1: ones you can access online. IBM has one that's connected
Speaker 1: to the web, meaning you can talk to that. This
Speaker 1: quantum com computerly have you can ask it questions. Yeah,
Speaker 1: but it's hard because you have to get these cubits
Speaker 1: built and then you have to get them to be stable,
Speaker 1: and sometimes these things fall apart. I mean, the basic
Speaker 1: principle of a quantum computer works if it's in isolation,
Speaker 1: but no computer is really in isolation. Interacts with the
Speaker 1: environment and so it gets messed up. And so these
Speaker 1: things are really finicky. There's not they're not easy to build,
Speaker 1: and so we're still getting good at building the bits.
Speaker 1: Like if you look at it will collapse into black
Speaker 1: or white, so you have to really protect it from
Speaker 1: anyone looking at your quantum computer until you actually want
Speaker 1: the answer exactly. Yeah, So technically these things are really tricky,
Speaker 1: but you know, technical problems get solved, and when there's
Speaker 1: a lot of money, it's stakes a lot of people
Speaker 1: work on them. And so I think quantum computers are
Speaker 1: going to come pretty rapidly and get larger and larger
Speaker 1: and more complicated. And so you know, we're at the
Speaker 1: point where we have ten fifteen cubic computers. They don't
Speaker 1: last for very long, so you can't do long complicated calculations,
Speaker 1: and they're huge, right, Like they take up the space
Speaker 1: of our room the way classical computers used to. You know,
Speaker 1: you have a little picture a classical computer from nineteen
Speaker 1: sixty It could like do less than your iPhone and
Speaker 1: it filled up a whole room. Right, Well, you might
Speaker 1: want to have a quantum computer in your phone, but
Speaker 1: like maybe right in fifty years, Yeah, perhaps if you
Speaker 1: needed to do that kind of stuff. Um, you know,
Speaker 1: if I if I pooh pooh the applications of quantum computers,
Speaker 1: then I risk going down in history. Is like one
Speaker 1: of those guys who said computers have a very specialized use.
Speaker 1: You might sell five or six worldwide. Nobody can ever
Speaker 1: predict how these things are going to change the side
Speaker 1: and how people will think to use them. Nobody wants
Speaker 1: to be that guy. No one wants to be that guy, right,
Speaker 1: But yeah, I think the future holds a big promise
Speaker 1: for quantum computers, and I think they'll crack open new
Speaker 1: kinds of problems that were hard before um. So far,
Speaker 1: there's sort of limited set of problems and quantum computers
Speaker 1: can solve. It's like it's as a new toy and
Speaker 1: we're trying to figure out exactly how to use it
Speaker 1: to definitely, you fun kind of thing. This is are
Speaker 1: having fun putting together. But it's not like it's can
Speaker 1: speed up every problem. Some people think, oh, quantum computers
Speaker 1: make everything faster. That's not the case. So it's not
Speaker 1: gonna be like a quantum lead. It will be more
Speaker 1: like a quantum skill. Are you saying it would be
Speaker 1: more like a quantum massage whatever that means? Oh my gosh. Well,
Speaker 1: I hope you guys enjoyed this deep dive into quantum computers. Yeah.
Speaker 1: And if you have questions about what we said and
Speaker 1: you didn't understand it, please send us feedback to feedback
Speaker 1: at Daniel and Jorge dot com. And if you have
Speaker 1: another question you think we we would take a part
Speaker 1: nicely you'd like to hear us talk about, send that
Speaker 1: to us as well. Or if you just want Daniel
Speaker 1: to give you a massage, just write at quantum Massage
Speaker 1: at Daniel Jorge dot com. That's right, I'll give you
Speaker 1: one bit of a massage, one quantum bit. All right.
Speaker 1: Thanks everyone for listening and tune in next time. See
Speaker 1: you next time. If you still have a question after
Speaker 1: listening to all these explanations, please drop us a line.
Speaker 1: We'd love to hear from you. You can find us
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Speaker 1: one word, or email us at feedback at Daniel and
Speaker 1: Jorge dot com.