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51:44big in physics. Physicists love to measure things extremely precisely. Okay. Now classical measurement is limited by something called the standard quantum limit. Okay. The idea is the quantum world is discrete which means for example if I want to measure photons that are coming into my photo detector there's going to be fluctuating power on that photo detector because photons are going to be arriving one by one. This is the idea of shot noise. Okay. And because the quantum world is what it is. It's quantum. There's all this discrete stuff. you're going to get an error based on whatever measurement because of
52:25the discreetness of the world that you are measuring. Okay? And that error goes like one over the square root of n where n is the number of particles that you've sort of observed. Okay? We want to go even beyond that, right? >> Because the fundamental limit when it comes to actually recording something is really the Heisenberg uncertainty limit, right? And what this particular paper is doing is what they've done is successfully split a cloud of atoms that they've made into a Bose Einstein condensate. They've split it into three. And what they're doing is using the entanglement between those clouds of atoms to then up their
53:08game on how sensitive they can measure something. They can do it with multiple parameters. So you can measure something here on the left. you can measure another thing on the right, so on and so forth. And you can do it across space. And they're very clever about how they're able to use this entanglement to then get beyond that standard quantum limit. They're starting to probe the real limit, >> which is the Heisenberg uncertainty principle, >> right? I will just note as someone who comes from the software world uh SQL meaning standard quantum limit is uh it's a little bit uh maybe have done a different naming convention there because SQL is a popular database.
53:49>> Oh really? Oh yeah SQL so so so it's it's >> for sure. >> I don't think physicists care though. >> They% you know the I'm sure they use SQL all the time. I mean I use it all the time in my work but yeah for us at least for the AMO guys SQL means standard quantum limit. It's okay. We We can always learn multiple acronyms. >> Yeah. Um context switching, right? >> Exactly. >> So, let's get into uncertainty and information. Right. When it comes to the real limit, it is the uncertainty principle that's been guided by Warner Heisenberg in 1927. He came out with the uncertainty principle and people have been chasing this limit ever since. This is the limit of the universe. You can't
54:30go beyond this just because of the nature of quantum mechanics and the nature of our reality. Right? The classical limit is the standard quantum limit 1 over square root of n. You've got shot noise because there's a uncertainty on how much you can measure based on discrete amount of stuff coming in. Now, here's the deal though. The Heisenberg uncertainty limit is a limit on the product of two observables. the the product of the noise on two observables. For example, the standard one that you think about is momentum and position, right? If I know my position really well, then I don't know my momentum that well and so on and so forth because the product of these two numbers, if one number is small, the
55:11other has to be big such that the product remains about the same. But what you could do is exactly what I said. If I really want to know my position very very well, I could not care about my momentum, I could squeeze my observation such that my delta on one axis is very big and my delta on another axis is really small. So instead of a circle where the error in my let's say x and y these are two different observables is the same my error on x could be really small that could be my position and my error on the y-axis which is my momentum could be very big because maybe I don't
55:52care >> maybe I don't care to actually measure that >> and when I do this with this quantum metrology I could get a 100 times better than my standard quantum limit and still stay above the Heisenberg uncertainty limit. >> Okay. Okay. >> Mhm. >> These are called squeezed states. Okay. Because you're squeezing in one direction and you're like stretching in the other direction and squeezing in the direction that you care about, >> right? We're we're basically saying we want to increase the level of precision in one of these two observed states or dimensions. >> Yeah. >> And we I'm trying to understand why. >> Yeah. >> But we'll get there. But the the first
56:34idea is instead of having an even distribution on error across both observed states, we're trying to maximize precision on one while giving