# A new story from The Ezra Klein Show

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I'd explain Google's quantum supremacy news but to do that I I have to make you eat your veggies by talking about physics but don't worry 'cause I got you I am here for you and we're all GonNa do this together so Kevin. What's a quantum computer? A quantum computer is a machine that performs calculations using the laws of quantum physics as opposed to. I guess your classical computer like your phone or your desktop computer that behaves according to the laws of classical physics so a classical computer computes using bits and bits can be either one ores zero so like the foundation of code basically the exactly. It's that's what that's what code is now a quantum computer doesn't use bits uses quantum bits or cubits and these two bits are made out of quantum material and a cube. It can be in a position of one or zero or it can be described by the probability that it's in one or the probability that's in the positions zero so what is the advantage of that system. The advantage of that system is is you have these many different possible states. Your quantum computer could be in when you are working through your calculation and each of those estates has a probability assigned to it. That's the key a regular computer or what computing. Experts would call a classical computer like your laptop or your phone. Those computers can only try one possible pathway at a time to get an answer but a quantum computer can get to the right answer more efficiently. That's not Super Burger intuitive. So here's a thought experiment. Imagine a ball and a hill. Your task is to get that ball to land on a specific spot at the bottom of the hill. So imagine that you're at the beginning of the COMPU- computation. You are at the top of the hill. You're going to roll a ball down the field and and can kind of go any number of ways down the hill and end up at any number of different spots at the bottom but there's only one spot that's correct in so if you're if you have a classical computer the best you can do is kind of role that ball down the hill and see where it lands and see if it's the correct answer or not so you're constantly running the ball up the hill and then you get to drop it once and then maybe you get the correct answer. If you don't you gotTa Roll it back up the hill and trial again. That's right IT'S A. It's a lot of effort. It takes takes a lot of time but with a quantum computer. You have the ability to kind of Structure Your Ju- bits. So that the path the ball takes down. The hill is in some ways the the most likely path it takes down. The Hill is the one that corresponds to the correct answer. Cancer at the bottom of the hill. So you can kind of tip the hill tip the scales in your favor in order to get to the correct answer a whole lot. Faster after that's right A lot faster. That is the whole Shebang right there. A quantum computer should theoretically be able to get you an answer. A heck of a lot faster Mr than a classical computer when it comes to speed. Sometimes the newest flashiest mode of transportation isn't the most reliable. So you have to ask yourself. When does performing a calculation with a quantum computer become undeniably more efficient than doing the same thing with a classical computer that in a nutshell is the quest for quantum supremacy to quantum supremacy is a benchmark that was set about seven years ago in two thousand twelve by a physicist named John Prescott at California Institute of Technology Caltech and what quantum supremacy means is a quantum computer can do something something that no ordinary classical computer can match? What exactly does that mean? There's this idea that quantum computers should be able to perform calculations. It's much faster than regular computers but a lot of people doubted whether it was possible to actually achieve a calculation like that in practice so quantum supremacy is the moment a quantum computer actually performs calculation. that a classical computer simply can't keep up with because if if you give classical computer enough time maybe even more time than we have left in the universe it can do anything. A quantum computer can do supremacy means a a quantum computer can do something in a categorically faster way. Then a classical computer can do it. The world's most powerful classical computer is it's called summit it's owned by. Am and it's as big as two basketball courts. Google's quantum computer on the other hand probably fits in your bedroom and it has a name to by the way. It's called Sycamore. So what Google did was. Give Sycamore a very specific problem to solve called a random circuit sampling problem. And what they showed is that their computer can solve this random circuit sampling problem in about two hundred seconds and the most powerful powerful classical computer in the world which is called summit. Will Google estimated. It would take that computer ten thousand years to solve the same problem that their computer solved in two hundred seconds. We will it. So what Google announced is that it basically dunked really really hard on. IBM's most powerful computer. The most powerful computer classical computer in the world it dunk tarred in the sense of this particular nuclear problem. And you could say if killed it that that feels like a big deal. Is it a big deal. It is a big deal. It's a big deal in a practical sense. There are lots of things things we can do if they only take a couple minutes to carry out the calculation that we can't do if we need years or tens of thousands of years except that if you ask IBM IBM who'll didn't dunk as hard as it says it did. IBM certainly skeptical. They issued a paper saying not so fast. They haven't actually done it because Google estimated in their paper that it would take a the most powerful ordinary computer ten thousand years to carry out this calculation and IBM said actually most powerful computer which we designed can do this in two and a half days probably even faster than that if we had time. Time to fine tune how we did it and I should also say that. IBM themselves they are. Perhaps Google biggest competitor in the effort to build a a quantum computer so as IBM just a sore loser or is this a very good point that they're making well the point they're making is good and it does point to something important written about supremacy. which is you're trying to prove that a quantum computer can do something faster than any classical computer can so proving moving supremacy truly proving supremacy would involve proving? There's no way a classical computer can do this kind of problem as fast as a quantum a computer and we don't have that kind of proof here it took the most powerful classical computer in the history of the world a computer that occupies an area the size of two basketball courts. It took that computer or would take that computer. nope say a minimum of two and a half days to do this calculation. If Google's quantum computer gets gets even a little bigger if instead of fifty three cubits they have seventy cubits now a classical computer that fills two basketball courts won't be L. to keep up at all. You need a computer. The size of a city to simulate that same calculation and that's the sense in which the quantum computer is doing anything's categorically faster than classical computer. And I think that difference is really what people have in mind when they talk about quantum supremacy missy. And that's why most people are pretty comfortable saying that. What Google did if it fully checks out is in fact demonstration of quantum supremacy so as IBM also also going to demonstrate supremacy anytime soon IBM has been on the record for a while now that they are not chasing the goal of quantum supremacy? They view it as has an artificial bench. Mar We could cross it and still not be doing anything useful so they at least in their public statements have been and much more practically minded so this is a difference between Google being the kind of basketball player that wants to two straight up flip in the air before dunking and IBM. That just wants to do a layup because they know that it works. And it's the same amount of points I'd say so and it it seems like Google all has been more animated by the basic science of it and kind of the sense of possibility and exploration my man Kevin with the perfect segue so so we've established that Google's quantum computer is significantly faster than the most powerful classical computer in the world. But what exactly are the possibilities with this. This our personal quantum computers in our future. That's after the break.