WEBVTT - Could quantum mechanics be deterministic? 0:00:09.560 --> 0:00:13.440 Quantum mechanics just doesn't seem to make sense. It tells 0:00:13.560 --> 0:00:17.520 us that the universe is fundamentally random, that some questions 0:00:17.560 --> 0:00:20.639 just don't have answers, that there's a limit to what 0:00:20.800 --> 0:00:25.400 can be known about reality, and that things change when 0:00:25.480 --> 0:00:27.600 we look at them. More than that, it tells us 0:00:27.640 --> 0:00:31.440 that reality is fundamentally different from what we have imagined. 0:00:31.800 --> 0:00:34.240 But what if that's not true? What if that's wrong? 0:00:34.920 --> 0:00:37.559 What if it were possible to build a theory of 0:00:37.640 --> 0:00:42.360 quantum mechanics that doesn't describe the universe as bizarrely random, 0:00:42.400 --> 0:00:46.320 that doesn't have any special role for observers, that doesn't 0:00:46.320 --> 0:00:50.519 suffer from the famous measurement problem, and that lets us 0:00:50.640 --> 0:00:54.040 think of the microscopic world as very similar to our 0:00:54.160 --> 0:00:58.360 familiar intuitive world. And what if this theory actually worked 0:00:58.480 --> 0:01:02.200 and was able to describe I've been predict experiments. That is, 0:01:02.760 --> 0:01:08.040 what if there's an intuitive alternative to mainstream quantum mechanics. 0:01:08.480 --> 0:01:28.000 If there were, why on Earth wouldn't it be embraced? Hi, 0:01:28.280 --> 0:01:31.080 I'm Daniel. I'm a particle physicist and a professor of 0:01:31.080 --> 0:01:34.080 physics that you see, Irvine, and I want to believe 0:01:34.160 --> 0:01:36.920 that the world makes sense. We are all drawn to 0:01:37.160 --> 0:01:40.240 basic questions about the nature of the universe. How does 0:01:40.280 --> 0:01:42.640 it work, why is it this way and not some 0:01:42.760 --> 0:01:45.440 other way? How did it all begin? And how will 0:01:45.480 --> 0:01:47.800 it all end? Physics is supposed to be a way 0:01:47.840 --> 0:01:51.120 to get answers to those questions, and so welcome to 0:01:51.160 --> 0:01:54.520 the podcast Daniel and Jorge explained the Universe and production 0:01:54.560 --> 0:01:57.480 of My Heart Radio, where this is precisely the kind 0:01:57.520 --> 0:01:59.800 of question we ask and the kind of answer we 0:02:00.040 --> 0:02:03.040 reach for. And the amazing thing is that physics kind 0:02:03.040 --> 0:02:07.200 of seems to work. It offers explanations, explanations that not 0:02:07.320 --> 0:02:10.960 only work because they could predict what happens in experiments, 0:02:11.160 --> 0:02:15.160 but explanations that usually make some kind of sense. The 0:02:15.320 --> 0:02:18.200 stories they tell us are mathematical and could be very 0:02:18.240 --> 0:02:20.560 different from the stories we guessed at. It turns out 0:02:20.600 --> 0:02:23.080 the Earth is billions of years old and not thousands, 0:02:23.120 --> 0:02:26.120 that stars are massive balls of fusion in the sky 0:02:26.400 --> 0:02:28.840 rather than tiny pin pricks in the screen. But in 0:02:28.880 --> 0:02:31.800 the end, these mathematical stories that physics tells us about 0:02:31.800 --> 0:02:34.720 the universe, they are coherent, they are sensible. We can 0:02:34.840 --> 0:02:38.600 use them to understand how the universe really is. Except 0:02:38.800 --> 0:02:42.480 in one area, quantum mechanics. While we do have a 0:02:42.520 --> 0:02:45.720 working theory, we struggle to make sense of it. What 0:02:45.760 --> 0:02:48.440 does it really mean? What is it telling us about 0:02:48.440 --> 0:02:51.400 how the world really is? And while we have lots 0:02:51.400 --> 0:02:55.040 of different interpretations, we struggle to accept the story that 0:02:55.080 --> 0:02:58.760 they tell us. Is the universe really random? Is everything 0:02:58.840 --> 0:03:02.040 really described by the wave function? Does it collapse when 0:03:02.040 --> 0:03:05.640 you observe it? Or split into millions of meta universes? 0:03:05.840 --> 0:03:08.520 Or do objects not really have any properties on their 0:03:08.520 --> 0:03:12.120 own to observe or all properties relative to the observer. 0:03:12.440 --> 0:03:15.639 None of these are easy to absorb, to click into 0:03:15.639 --> 0:03:18.680 our minds and let you say, oh, yeah, I get it, 0:03:18.800 --> 0:03:21.480 that's how the universe is. But what if there was 0:03:21.520 --> 0:03:24.680 a version of quantum mechanics that was more intuitive, that 0:03:24.760 --> 0:03:28.880 was deterministic, that didn't need some observer effect or multiple 0:03:29.000 --> 0:03:32.920 universes or a redefinition of the nature of reality. Well, 0:03:32.960 --> 0:03:36.280 today we will be exploring a less popular theory of 0:03:36.360 --> 0:03:41.320 quantum mechanics that doesn't rely on randomness and uncertainty. It 0:03:41.400 --> 0:03:44.720 tells us that what is happening to tiny particles is 0:03:44.840 --> 0:03:47.880 much simpler and easier to swallow, and we'll talk about 0:03:48.000 --> 0:03:52.560 why it's been overlooked by mainstream physics. So today on 0:03:52.600 --> 0:04:01.160 the podcast, we'll be asking the question the quantum mechanics 0:04:01.480 --> 0:04:05.040 have to be so random? My friend and co host 0:04:05.160 --> 0:04:07.880 Orges on a break, so I'm continuing our series of 0:04:07.920 --> 0:04:12.360 conversations with experts in quantum mechanics. We spoke to Adam 0:04:12.440 --> 0:04:16.640 Becker about mainstream quantum mechanics, to Carlo Rovelli about his 0:04:16.760 --> 0:04:21.000 theory of relational quantum mechanics, to Sean Carroll about the 0:04:21.040 --> 0:04:24.840 many world interpretation, and today we are speaking to an 0:04:24.880 --> 0:04:30.600 expert on pilot wave theory, also known as Boemian mechanics. 0:04:31.360 --> 0:04:34.080 So it's my great pleasure today to introduce all of 0:04:34.120 --> 0:04:37.839 you to Professor Valia Alori, who, if I understand correctly, 0:04:37.920 --> 0:04:41.360 holds two pH d s, one in physics and one 0:04:41.480 --> 0:04:44.240 in philosophy, so she's the perfect person for us to 0:04:44.240 --> 0:04:48.680 talk to about the crazy philosophical consequences of quantum mechanics. 0:04:48.680 --> 0:04:51.560 She's also a full professor in the Department of Philosophy 0:04:51.640 --> 0:04:54.920 at Northern Illinois University and a fellow at the John 0:04:54.960 --> 0:04:58.760 Bell Institute for Foundations of Physics. Professor A Lorii, welcome 0:04:58.839 --> 0:05:01.680 the podcast. Thank you for having me, well, thank you 0:05:01.720 --> 0:05:04.080 for coming here to talk to us about the mysteries 0:05:04.120 --> 0:05:07.159 of quantum mechanics. Before we get into the details of 0:05:07.279 --> 0:05:09.520 pilot wave theory, I thought we should take a step 0:05:09.560 --> 0:05:13.599 back and remind ourselves why we have so many theories 0:05:13.640 --> 0:05:16.840 of quantum mechanics and why there are still so many 0:05:16.960 --> 0:05:19.800 questions about it. To me, the basic question we have 0:05:19.880 --> 0:05:23.200 about quantum mechanics is what is going on? How do 0:05:23.279 --> 0:05:27.200 we understand the story that it's telling us. Our intuition 0:05:27.279 --> 0:05:29.640 is to think of particles as tiny dots of matter, 0:05:29.680 --> 0:05:33.400 but quantum mechanics usually tells us that they are basically different, 0:05:33.480 --> 0:05:36.800 that they are fundamentally different kinds of things because they 0:05:36.800 --> 0:05:41.960 can maintain two contradictory possibilities at once. There's also this 0:05:42.240 --> 0:05:45.480 wave function that seems to control what happens, but then 0:05:45.520 --> 0:05:47.799 it collapses when you touch it, but it's not clear 0:05:47.880 --> 0:05:50.880 what the rules of that collapse are. It's so hard 0:05:50.960 --> 0:05:53.520 to get a mental picture of what's going on with 0:05:53.560 --> 0:05:56.640 the little particles. So how do you approach this question 0:05:56.680 --> 0:06:01.320 of trying to understand what quantum mechanics? So first of all, 0:06:01.760 --> 0:06:04.839 let me just say that I'm not sure that we 0:06:04.920 --> 0:06:09.680 should understand quantum mechanics philosophically there is a sense in 0:06:09.720 --> 0:06:13.400 which we don't understand quantum mechanics even physically as a 0:06:13.400 --> 0:06:17.440 physical theory, because I mean, the theory seems to be 0:06:17.480 --> 0:06:22.240 talking about you know, electrons and protons and matter in 0:06:22.360 --> 0:06:26.000 general and fields, but when you actually look at the formalism, 0:06:26.040 --> 0:06:30.240 it's unclear exactly what plays the rollers of what. So 0:06:30.279 --> 0:06:33.599 we do have a an equation, the Shouldinger equation, which 0:06:33.640 --> 0:06:35.600 is a question of the evolution of the wave function. 0:06:35.960 --> 0:06:38.760 Should we understand the way function as a physical object. 0:06:39.120 --> 0:06:41.719 If the wave function is a physical object, what does 0:06:41.720 --> 0:06:45.400 it represent? Does it represent particles, does it represent fields? 0:06:45.600 --> 0:06:48.080 Since I was a student, just to put it bluntly, 0:06:48.120 --> 0:06:51.080 I really had trouble relating to the theory as a 0:06:51.160 --> 0:06:55.039 physics student. But even granting that the it's accurate to 0:06:55.080 --> 0:06:58.640 talk about that as a theory about something. Let's put 0:06:58.680 --> 0:07:02.080 it this way. The ory, I would say, is either 0:07:02.480 --> 0:07:08.800 empirically inadequate or it's incomplete. Why is that? Well, because 0:07:09.160 --> 0:07:11.520 I just said that, you do have this equation, which 0:07:11.520 --> 0:07:15.280 is the shrining equation, which is a again equestion of 0:07:15.320 --> 0:07:18.800 evolution of an objicle the wave function, and the wave 0:07:18.840 --> 0:07:21.880 function is a called like that because it's a wave 0:07:22.160 --> 0:07:26.520 so and wave can superimpose. You know, you throw a 0:07:26.640 --> 0:07:29.400 rock in the pond, right, throw another rock in the pond. 0:07:29.480 --> 0:07:32.320 Then you see waves from one rock and then you 0:07:32.360 --> 0:07:35.320 see the other rock. They superimposed. You have interference and 0:07:35.360 --> 0:07:37.800 the fraction of this kind of behavior that you would 0:07:37.840 --> 0:07:42.280 attribute to waves. Okay, And so since there's two superimposed. 0:07:42.560 --> 0:07:45.320 If you think of the wave functions are presenting objects 0:07:45.320 --> 0:07:48.800 of physical objects right at the microscopic level, they could 0:07:48.840 --> 0:07:52.560 be in a superposition state, right, and nucluse that adioactive 0:07:52.560 --> 0:07:55.480 substance of subsort could be in the superposition of a 0:07:55.560 --> 0:07:59.440 decade state or a non decade state. And by superposition 0:07:59.520 --> 0:08:02.840 you mean that there's two possibilities for an object. It 0:08:02.880 --> 0:08:04.960 could be spin up or spin down, or decade or 0:08:04.960 --> 0:08:08.080 not decade. There's two options for the situation. It can 0:08:08.080 --> 0:08:11.160 actually be in yes, in a sense, yes, more generally, 0:08:11.200 --> 0:08:14.560 I mean mathematically, this is the mathematical property of the equation, right. 0:08:14.600 --> 0:08:17.160 I mean the prototype example is the problem of the 0:08:17.160 --> 0:08:19.360 shrilling a cat, right, in which you do have this 0:08:19.480 --> 0:08:21.960 cat which is in a box. Right in the box 0:08:21.960 --> 0:08:24.440 that is this vial of poison. De vial of poison 0:08:24.680 --> 0:08:30.080 will break because it's connected to this radioactive substance, so 0:08:30.160 --> 0:08:34.560 it will break if the substance will decay. If nothing happens, 0:08:34.720 --> 0:08:37.199 it will not break. So what happens is that if 0:08:37.200 --> 0:08:42.760 the nucleus decase, bile of poison breaks and the cat dies. Okay, 0:08:42.920 --> 0:08:46.120 So that's a possible state of affairs. Otherwise nothing happens 0:08:46.120 --> 0:08:49.240 in the cat stays alive, okay. And so what happens 0:08:49.440 --> 0:08:54.080 is that, however, given the superposition state possibility, given the 0:08:54.080 --> 0:08:57.280 fact that there is a possibility of having a superposition 0:08:57.320 --> 0:09:00.760 state as a true physical state for this system, then 0:09:01.080 --> 0:09:05.520 you could also have this microscopic superposition of decade and 0:09:05.559 --> 0:09:08.080 not decayed, which actually spread out of the cat. And 0:09:08.120 --> 0:09:13.760 so the theory predicts this microscopic superposition which we never 0:09:13.840 --> 0:09:16.680 ever observed. They are not observable. That's not what we 0:09:16.720 --> 0:09:20.120 have experienced. Off So there is a very strong sense 0:09:20.320 --> 0:09:24.640 in which the theory as it is is empirically inadequate, 0:09:24.760 --> 0:09:27.000 because when we open the box and we when we 0:09:27.080 --> 0:09:30.320 check on the cat, the cat is either dad or alive. 0:09:30.679 --> 0:09:33.240 So what I'm hearing you saying is that quantum mechanics 0:09:33.320 --> 0:09:37.240 is useful as a description of these microscopic states. But 0:09:37.320 --> 0:09:41.800 which I think you mean like quantum particles, electrons and photons, etcetera. 0:09:41.880 --> 0:09:44.320 But that we don't really understand what it means and 0:09:44.480 --> 0:09:47.600 we can't access it directly. We can't like see these things. 0:09:47.760 --> 0:09:50.600 We have to interact with them using macroscopic objects like 0:09:50.640 --> 0:09:54.160 detectors or our fingers or cats, etcetera, which don't have 0:09:54.200 --> 0:09:56.320 the same quantum properties, And so it doesn't really answer 0:09:56.360 --> 0:09:59.120 the question of like, what's actually going on in the 0:09:59.160 --> 0:10:02.600 microscopic leve Is that a summary of the problem. Yes, 0:10:02.640 --> 0:10:05.439 Actually it's more than that. So not only doesn't explain 0:10:05.480 --> 0:10:09.840 what's going on intuitively at the microscopic level, but also 0:10:09.920 --> 0:10:13.160 if you try to apply the theory to everything, including 0:10:13.240 --> 0:10:16.400 cats and detectors and stuff like that, the theory doesn't 0:10:16.440 --> 0:10:19.400 give you what you observe. So it's really bad for 0:10:19.440 --> 0:10:22.240 the theory. The theory doesn't I mean, it is actually 0:10:22.240 --> 0:10:25.520 falsified directly by the fact that the training Garry question 0:10:25.559 --> 0:10:28.040 is it's a linear I think because you're saying that 0:10:28.080 --> 0:10:30.800 they suggest that cats should also be in superpositions, and 0:10:30.840 --> 0:10:33.600 fingers and detectors and everything should be in superpositions. But 0:10:33.679 --> 0:10:35.400 that's not what we observe. That's what you mean by 0:10:35.440 --> 0:10:39.960 experimentally falsifying, Yes, exactly, and of course, I mean, you know, 0:10:40.000 --> 0:10:43.240 the family fathers were not naive and the newness okay, 0:10:43.280 --> 0:10:45.559 and that's why they proposed, at least that's what for 0:10:45.720 --> 0:10:49.120 Neuman did, right. He proposed that there is actually a 0:10:49.160 --> 0:10:52.280 second evolution a question for the wave function. And so 0:10:52.320 --> 0:10:55.920 they say, okay, right, you don't want macroscopy superposition. Okay, 0:10:56.000 --> 0:10:57.880 So when do you get them again? Oh, when there 0:10:57.960 --> 0:11:01.120 is a measurement. Uh huh. So when the measurement is performed, 0:11:01.200 --> 0:11:04.800 then there is a different evolution equation. The wave function 0:11:04.960 --> 0:11:08.600 randomly collapses in one of the terms a superpositional when 0:11:08.600 --> 0:11:11.000 you open the door and you see the cat ha ha, 0:11:11.320 --> 0:11:15.040 the wave function actually collapses. So you write in a 0:11:15.160 --> 0:11:19.000 sense right as a detector, right, you collapse the wave function. 0:11:19.080 --> 0:11:20.640 The issue there is that we don't have a clear 0:11:20.640 --> 0:11:23.280 definition of what a measurement is and when it happens. 0:11:23.360 --> 0:11:25.600 Because you can imagine, you know, if I'm poking something 0:11:25.640 --> 0:11:27.560 with my finger, the tip of my finger is still 0:11:27.559 --> 0:11:30.040 a microscopic particle, So why should it collapse the way 0:11:30.040 --> 0:11:32.200 function and two particles on the tip of my fingers 0:11:32.200 --> 0:11:34.520 should still be a quantum mechanical system. So there's no 0:11:34.640 --> 0:11:38.319 like clear line when something becomes classical or microscopic when 0:11:38.360 --> 0:11:41.120 the wave function should collapse. Yes, exactly. I mean we 0:11:41.200 --> 0:11:45.240 don't know who does the collapsing, who kills the cat? Right? 0:11:45.360 --> 0:11:48.760 So is it me when I open the door, or 0:11:48.880 --> 0:11:51.800 is it my consciousness? We don't really want to enter 0:11:51.960 --> 0:11:55.559 into that. So it is a problem that you're suggesting. Namely, 0:11:55.640 --> 0:11:59.480 it's not a precise physical theory. It doesn't really define 0:11:59.600 --> 0:12:02.320 what a measurement is. Because I mean, this is puzzling, 0:12:02.320 --> 0:12:05.400 because we just would like measurement just to be physical 0:12:05.480 --> 0:12:08.640 processes like anything else, right, I mean, they're made of particles, 0:12:08.800 --> 0:12:12.000 quantum particles, and so why are they special? So there 0:12:12.040 --> 0:12:14.720 is a sense in which started from this, which is 0:12:14.720 --> 0:12:18.320 called the measurement problem, because I mean, we are actually 0:12:18.640 --> 0:12:21.240 measuring what is the state of the cat, and the 0:12:21.600 --> 0:12:24.280 cat is actually measuring what is the state of the particle. 0:12:24.840 --> 0:12:28.079 Another way of putting this would be that measurements, when 0:12:28.080 --> 0:12:31.920 you're performing a measurement. Quantum theory says that measurements do 0:12:31.960 --> 0:12:35.640 not have a precise result. Okay, so like the cat 0:12:35.720 --> 0:12:40.520 doesn't have a precise state, and so various people call 0:12:40.600 --> 0:12:43.439 them interpretation. But I actually think that they are different theories, 0:12:43.559 --> 0:12:46.480 but they have different solutions of these problem so to speak. 0:12:46.800 --> 0:12:51.199 So bo mechanics is one of those. It does solve 0:12:51.240 --> 0:12:54.800 this problem, even if I do think that's not the way. 0:12:54.840 --> 0:12:58.080 The reason why it was proposed. So this theory was 0:12:58.600 --> 0:13:01.480 proposed by I mean, the first version of this was 0:13:01.520 --> 0:13:05.560 proposed by the Brody in ninety three as part of 0:13:05.600 --> 0:13:09.760 his dissertation. So according to this theory, what happens is 0:13:09.800 --> 0:13:13.040 that I just like very very some people like to 0:13:13.080 --> 0:13:17.240 put it and romantic, right, something very plan and boring 0:13:17.760 --> 0:13:20.680 in a sense obvious because it's according to this theory, 0:13:20.760 --> 0:13:24.240 matter is made of particles, just liking classical mechanics, but 0:13:25.240 --> 0:13:28.800 they do have a different evolution equation than quantum theories. 0:13:28.840 --> 0:13:30.680 In this theory there is this object which is the 0:13:30.720 --> 0:13:34.360 wave function, which is the same guy as ordinary quantum theory, 0:13:34.600 --> 0:13:37.679 but it devolves according to Shrinninger equation. So you do 0:13:37.760 --> 0:13:40.840 have this an evolution a question for the particles, which 0:13:40.880 --> 0:13:42.960 is first to order, and then you have an object 0:13:43.000 --> 0:13:46.640 which is the wave function, which evolves like in regular 0:13:46.720 --> 0:13:49.680 quantum mechanics according to the Shrininger equation. So then in 0:13:49.760 --> 0:13:52.520 the Copenhagen interpretation, the one most people are familiar with. 0:13:52.600 --> 0:13:54.720 The wave function is supposed to be everything is supposed 0:13:54.760 --> 0:13:57.600 to describe the whole system, and particles when we're not 0:13:57.640 --> 0:14:00.240 looking at them, sort of operated according to this wave auction, 0:14:00.400 --> 0:14:03.480 which you know evolves according to the Shortinger equation. But 0:14:03.559 --> 0:14:06.000 then there's this weird second bit where things collapse to 0:14:06.160 --> 0:14:09.080 particle like behavior that we observe when you look at them. So, 0:14:09.160 --> 0:14:11.360 for example, you have a particle that's supposed to hit 0:14:11.360 --> 0:14:14.040 the screen, the whole wave hits the whole screen, but 0:14:14.559 --> 0:14:17.120 at some point when it interacts, when that measurement happens, 0:14:17.120 --> 0:14:19.080 then it becomes a single point, a flash of light 0:14:19.120 --> 0:14:21.680 on that screen. And so you're saying that Bomian mechanics 0:14:21.800 --> 0:14:24.560 is different because not only do you have the wave function, 0:14:24.600 --> 0:14:26.760 but you also have the particles. It's not like this. 0:14:27.080 --> 0:14:31.320 There's sometimes waves and then sometimes particles. They're always particles, 0:14:31.320 --> 0:14:34.000 but they're governed by this wave that sort of guides 0:14:34.080 --> 0:14:37.920 them through their path. Yes, so there are always particles. 0:14:38.000 --> 0:14:40.480 That's what matter is made off. Tables and chairs and 0:14:40.560 --> 0:14:43.840 people and screens and detectors and whatever are all made 0:14:43.840 --> 0:14:47.200 of particles. So what happens is that these particles their 0:14:47.280 --> 0:14:52.400 trajectories is mathematically written down in terms of this wave function, 0:14:52.880 --> 0:14:55.160 and this way function in itself evolves according to a 0:14:55.320 --> 0:14:57.920 given equation. Okay, So usually what you said is kind 0:14:57.920 --> 0:15:00.920 of important because some I mean, very common way of 0:15:00.960 --> 0:15:04.040 describing the theory, which is also called because of this reason, 0:15:04.120 --> 0:15:08.040 the pilot wave theory, is that this particle are pushed 0:15:08.080 --> 0:15:13.920 around by this wave. Okay. So the user slogan is, oh, 0:15:14.040 --> 0:15:20.360 it's not particle end waves or waves, it's particle end waves. Okay. 0:15:20.600 --> 0:15:22.800 So there is a sense in which this is true, 0:15:23.040 --> 0:15:24.800 in the sense that there are particles and there is 0:15:24.800 --> 0:15:27.880 also this wave function. However, I think that it is 0:15:28.320 --> 0:15:31.400 kind of misleading to think of that in these terms, 0:15:32.200 --> 0:15:35.200 because if you think about what kind of entity the 0:15:35.240 --> 0:15:38.840 wave function is, it is a wave, but not a 0:15:38.840 --> 0:15:42.000 wave in three dimensional space. Okay. If you think of 0:15:42.200 --> 0:15:44.680 how to represent the wave function, what the wave function 0:15:44.760 --> 0:15:49.800 really is, It's a function of all the particles, right, 0:15:49.880 --> 0:15:52.680 It is a function of the configuration in the case 0:15:52.720 --> 0:15:55.360 of bow Mean mechanics, the function of the configuration about 0:15:55.400 --> 0:15:58.880 the particles. So it has three dimensions for every particle. 0:15:59.040 --> 0:16:02.200 So in total it has three n dimensions. If the 0:16:02.280 --> 0:16:04.960 universe is composed of and particles, so it's not a 0:16:05.080 --> 0:16:08.320 field into adimensional space. The way function, then, just to 0:16:08.320 --> 0:16:10.720 be clear, talks about the trajectory of all of the 0:16:10.800 --> 0:16:13.800 particles in the universe, and so they're all sort of 0:16:14.000 --> 0:16:18.320 combined into this one grand object. The way function mechanics 0:16:18.360 --> 0:16:22.520 talks about is the way function of the universe. So 0:16:22.600 --> 0:16:25.080 the one that evolves according to the shooting their question 0:16:25.200 --> 0:16:28.440 is the way function of the universe. So I do 0:16:28.520 --> 0:16:31.880 have two things to clarify here. So the first thing is, 0:16:32.040 --> 0:16:36.200 so how we should interpret this wave function physically. It's 0:16:36.240 --> 0:16:38.840 an open question. I mean, philosophers and physicists are talking 0:16:38.880 --> 0:16:41.040 about this all the time. But I do think if 0:16:41.040 --> 0:16:43.480 you describe b My mechanics as I just did name 0:16:43.480 --> 0:16:45.760 it is a theory of particles with the wave function 0:16:45.840 --> 0:16:49.160 defining that trajectory, and you can understand that the way 0:16:49.160 --> 0:16:52.040 function as pushing the particles just in the same way 0:16:52.080 --> 0:16:57.800 as you understand gravity is pulling stuff right on the ground. Okay, 0:16:58.200 --> 0:17:00.440 So it's I think that the best this is my 0:17:00.520 --> 0:17:03.040 personal take on this, is that the best way of 0:17:03.120 --> 0:17:06.240 understanding the way function in Bowman mechanics is to think 0:17:06.240 --> 0:17:09.600 of that as law like right, It's part of the 0:17:09.720 --> 0:17:11.960 ingredients of the law of nature, something that you need 0:17:12.160 --> 0:17:14.840 right in order to specify the right trajectory, the one 0:17:14.880 --> 0:17:18.240 that you observe. And so the other thing was about 0:17:18.280 --> 0:17:20.840 the way function of the universe. So the fact that 0:17:21.000 --> 0:17:24.080 the way function is a function of all these particles 0:17:24.240 --> 0:17:26.800 is something that leads to a very important feature of 0:17:26.840 --> 0:17:30.120 Bonan mechanics, which is it's no locality. And I want 0:17:30.119 --> 0:17:32.160 to talk about non locality in a minute, but first 0:17:32.240 --> 0:17:33.439 I just want to make sure that we have a 0:17:33.480 --> 0:17:35.800 clear sense of what's going on here. So we talked 0:17:35.840 --> 0:17:38.560 about how the problem with quantum mechanics was this measurement 0:17:38.640 --> 0:17:41.440 problem that what happens when you measure this wave and 0:17:41.520 --> 0:17:44.360 it collapses into a particle. So how exactly does bow 0:17:44.400 --> 0:17:47.320 mean mechanics solve that problem? Is it because things are 0:17:47.320 --> 0:17:49.760 always a particle and so when you look at them, 0:17:49.800 --> 0:17:51.560 they were a particle and it's no big deal, and 0:17:51.600 --> 0:17:53.520 this is where it was, and it has like a 0:17:53.640 --> 0:17:56.160 well defined trajectory that in bow Mean mechanics you really 0:17:56.200 --> 0:17:59.439 can think about like electrons as tiny little dots of 0:17:59.520 --> 0:18:02.639 matter flying through the universe, the way planets fly through 0:18:02.680 --> 0:18:05.320 the Solar system. Yes, I think that's right in the 0:18:05.359 --> 0:18:08.119 case of the cat. The cats made of particles like 0:18:08.160 --> 0:18:12.240 everything else, So it is either dead or alive. Okay. 0:18:12.440 --> 0:18:17.120 The cat is either dead or alive at all times. Okay, 0:18:17.160 --> 0:18:20.600 So the macroscopic superposition should not belong to the wave functions. 0:18:20.640 --> 0:18:23.160 But the wave function is not what cat is made of. 0:18:23.320 --> 0:18:26.280 The cat was made of particles and particulars a precise location, 0:18:26.359 --> 0:18:28.720 which is what it is right, either in the dead 0:18:28.800 --> 0:18:31.119 camp or a in the life camp. So this is 0:18:31.200 --> 0:18:33.280 really different from the way people are sort of taught 0:18:33.320 --> 0:18:36.359 to think about quantum mechanics. That information isn't there until 0:18:36.400 --> 0:18:39.240 you measure it, that there's a fuzziness to the universe 0:18:39.320 --> 0:18:42.760 that is fundamentally random, all these really alien elements of 0:18:42.800 --> 0:18:45.280 quantum mechanics that make it so weird. Bo Mean mechanics 0:18:45.280 --> 0:18:47.200 seems to sort of like chuck that out the window 0:18:47.240 --> 0:18:50.520 and say, no, everything actually is determined. There is no 0:18:50.680 --> 0:18:54.120 randomness or uncertainty. There's just some information you sometimes haven't 0:18:54.119 --> 0:18:56.560 measured yet, but it's really there. That the cat really 0:18:56.680 --> 0:19:00.000 is dead or is alive. It's never sort of uncertain. 0:19:00.440 --> 0:19:02.879 Is that true? That there's really no randomness, no true 0:19:03.000 --> 0:19:06.200 randomness In Boomian mechanics. It depends on what is meant 0:19:06.200 --> 0:19:08.359 by that. So it is true that the cat is 0:19:08.359 --> 0:19:11.160 either dead or alive. It is true that the particles 0:19:11.240 --> 0:19:14.080 even passes through one sleet or the other sleet. It 0:19:14.160 --> 0:19:16.560 is true that when you observe a flash on the screen, 0:19:16.720 --> 0:19:19.879 that was coming from a particle that traveled all the 0:19:19.920 --> 0:19:22.439 way from the source to the screen. And it is 0:19:22.440 --> 0:19:26.320 true that there is no fuzziness. That's why I think 0:19:26.359 --> 0:19:30.000 that Bomian mechanics is physically clear. And the question is okay, 0:19:30.000 --> 0:19:33.080 so is there no randomness? Well, now there is randomness 0:19:33.160 --> 0:19:36.520 because the prediction of Bomian mechanics are provable to be 0:19:36.760 --> 0:19:41.200 the same as quantum mechanics. And quantum mechanics predicts probabilities. Right, 0:19:41.440 --> 0:19:45.400 the traditional stories that you do get only the probabilities 0:19:46.119 --> 0:19:48.680 of the results. Right, you obtain this, this or that 0:19:49.200 --> 0:19:51.760 not with a definite outcome. For sure, you have a 0:19:52.040 --> 0:19:56.679 probability distribution of the experimental results. So the legitimate question 0:19:56.760 --> 0:20:00.480 is where is the probability is coming from in Bomia mechanics. 0:20:00.880 --> 0:20:04.640 They come from the fact that So I mean, this 0:20:04.720 --> 0:20:09.199 is more general question about how is it possible to 0:20:09.240 --> 0:20:13.040 get probabilities if you have a deterministic theory. Deterministic theory, 0:20:13.040 --> 0:20:15.359 you have one past, one future, right if you know 0:20:15.440 --> 0:20:17.960 the law. If you not the initialis condition, you know everything, right, 0:20:18.160 --> 0:20:21.680 everything is determined. If you have this laplacean demon knows 0:20:21.720 --> 0:20:24.280 it at all and everything he knows everything. So this 0:20:24.400 --> 0:20:27.560 is a deterministic theory. So where the probability is coming from. 0:20:27.600 --> 0:20:30.760 They're coming from the initiative conditions. Okay, so there are 0:20:30.760 --> 0:20:34.760 two elements here, right. In determinism is something like that, 0:20:34.920 --> 0:20:38.200 given the initiative conditions and given the laws, you know everything. 0:20:38.400 --> 0:20:40.879 So if you do know the laws and you do 0:20:40.960 --> 0:20:43.439 know that, I mean principle, you can predict anything. I 0:20:43.440 --> 0:20:46.160 want to talk more about this randomness and initial conditions, 0:20:46.200 --> 0:21:01.440 but first let's take a quick break. All right, we're back, 0:21:01.480 --> 0:21:05.160 and we are talking about Bomian mechanics, a really fascinating 0:21:05.359 --> 0:21:09.280 quantum theory that describes the universe as filled with actual, 0:21:09.359 --> 0:21:12.080 tiny little dots of matter moving on what are like 0:21:12.200 --> 0:21:16.400 classical paths, but guided by a wave function that gives 0:21:16.440 --> 0:21:19.560 them the appearance of wave like behavior. And the element 0:21:19.600 --> 0:21:22.320 that we're talking about right now is this question of randomness. 0:21:22.400 --> 0:21:25.200 In traditional quantum mechanics, we are told that the universe 0:21:25.359 --> 0:21:28.800 is fundamentally random, that there aren't hidden variables that control 0:21:29.080 --> 0:21:32.080 what actually happens. But Boian mechanics says the opposite. It 0:21:32.080 --> 0:21:35.560 says that things are actually determined by the initial conditions, 0:21:35.640 --> 0:21:38.199 and that if you do the same experiment multiple times 0:21:38.200 --> 0:21:41.119 with exactly the same initial conditions, you should get the 0:21:41.160 --> 0:21:43.480 same output. So I'm a particle physicist and at the 0:21:43.520 --> 0:21:46.800 Large Hadron Collider we smash protons together multiple times, and 0:21:46.840 --> 0:21:50.160 we often say that if we smash those protons together 0:21:50.160 --> 0:21:53.000 with exactly the same initial conditions, we would still get 0:21:53.040 --> 0:21:56.359 different outcomes every time. That is quantum mechanical, and that 0:21:56.480 --> 0:22:00.760 it's drawn from some probability distribution that somewhere seriously, the 0:22:00.840 --> 0:22:03.760 universe is like rolling the dye based on this probability 0:22:03.760 --> 0:22:06.639 distribution and deciding what happens on the giving collision. But 0:22:06.680 --> 0:22:10.600 you're saying that Bomian mechanics is deterministic, and that if 0:22:10.600 --> 0:22:13.520 I get two different collisions giving me two different outcomes, 0:22:13.560 --> 0:22:16.760 that's because the initial conditions were slightly different, the protons 0:22:16.800 --> 0:22:19.280 that a slightly different energy or slightly different angle, and 0:22:19.280 --> 0:22:21.760 that if it was actually able to repeat the same 0:22:21.840 --> 0:22:24.480 exact experiment, I should get the same exact outcome, is 0:22:24.480 --> 0:22:26.720 that right? So yes, so so so if you say 0:22:26.720 --> 0:22:30.040 that you do have this distribution of the particles, the 0:22:30.080 --> 0:22:33.679 particles of distributed according to quantum ecalibbon distribution, and it 0:22:33.840 --> 0:22:37.800 is an equilibient distribution and nothing changes anymore, then that's 0:22:37.880 --> 0:22:41.000 the most complete information that you may have about this particles. 0:22:41.000 --> 0:22:43.600 And so we don't have more knowledge than this about 0:22:43.960 --> 0:22:47.960 the particles. Then we have absolute tons certainty about the 0:22:48.000 --> 0:22:52.160 precise positions of the particles. And so this plays out 0:22:52.320 --> 0:22:56.359 into having a distribution of the outcomes at the end 0:22:56.400 --> 0:22:59.800 of the experiment. I see. So we have particles which 0:22:59.800 --> 0:23:03.440 go through the experiment using deterministic laws. So the entire 0:23:03.480 --> 0:23:06.640 outcomes determined for each particle based on how it came 0:23:06.640 --> 0:23:10.360 into the experiment. But we have some distribution of inputs 0:23:10.359 --> 0:23:12.400 at the particles when they come into the experiment. They're 0:23:12.440 --> 0:23:16.119 never all actually at the same angle or location or whatever. 0:23:16.160 --> 0:23:19.119 There's some variation there and that gives a variation in 0:23:19.200 --> 0:23:21.400 the output. So not a randomness, but you have sort 0:23:21.400 --> 0:23:24.280 of variation and the inputs gets translated to a variation 0:23:24.400 --> 0:23:26.360 on the outputs, sort of like you know that game 0:23:26.359 --> 0:23:28.520 where you drop a ball and it goes left and right, 0:23:28.520 --> 0:23:29.800 and left and right and left and right. It sort 0:23:29.800 --> 0:23:32.560 of chaotic. It's very hard to predict exactly what slot 0:23:32.560 --> 0:23:35.119 it's going to go into. But in theory, if you 0:23:35.160 --> 0:23:37.600 did drop it exactly the same place twice, it should 0:23:37.680 --> 0:23:40.040 end up in the same slot twice. So boomy and 0:23:40.040 --> 0:23:42.080 mechanics describes the universe that way that you have some 0:23:42.160 --> 0:23:45.000 like variation in how the balls start to drop, which 0:23:45.040 --> 0:23:47.280 is how you get a variation in the output. But 0:23:47.440 --> 0:23:50.760 each trajectory of each one really is like a tiny, 0:23:50.800 --> 0:23:53.600 classical little baseball. That's crazy to me. I mean that 0:23:53.640 --> 0:23:56.760 requires like a whole rethinking of the idea of quantum mechanics, 0:23:56.760 --> 0:23:59.360 because I've spent twenty years getting used to this concept 0:23:59.440 --> 0:24:02.840 of the universe being random and unavailable and fuzzy, and 0:24:02.840 --> 0:24:04.679 this is now saying, oh, no, you actually don't have 0:24:04.720 --> 0:24:08.120 to take that whole weird route after all. Yes, that's right, 0:24:08.200 --> 0:24:10.960 so you don't have to and so why go for it? 0:24:11.040 --> 0:24:13.399 So I I mean, there is this is uncertainty that 0:24:13.480 --> 0:24:16.760 you have regarding the nition then the configuration, right, initial configuration, 0:24:16.800 --> 0:24:19.320 But that's it, right, you don't have to transform that 0:24:19.359 --> 0:24:23.960 into in the necessarily into somehow random trajectories or randomness 0:24:24.280 --> 0:24:27.040 more radical levels. But where is the fuzziness come from 0:24:27.080 --> 0:24:30.160 in the beginning? I mean, does the universe start with fuzziness? 0:24:30.200 --> 0:24:32.960 Because the standard picture we have, like why the universe 0:24:33.040 --> 0:24:35.600 is not totally smooth while we have galaxies here and 0:24:35.640 --> 0:24:38.280 not over there, is that we had some like quantum 0:24:38.320 --> 0:24:41.359 fluctuations in the early universe that gave us densities which 0:24:41.520 --> 0:24:43.520 you know, dot dot dot. Billions of years later we 0:24:43.560 --> 0:24:46.760 have galaxies. Where did those fluctuations in the density of 0:24:46.760 --> 0:24:50.120 the early universe come from, If not from quantum randomness, 0:24:50.160 --> 0:24:53.840 is it some pre pre initial condition before the Big Bang? Yeah, well, 0:24:53.880 --> 0:24:57.359 I have no idea, I mean, but I mean this 0:24:57.440 --> 0:25:00.520 is I think it's a very very important thing to notice. Right. So, 0:25:00.560 --> 0:25:03.040 if you do have a theory, which is like moving mechanics, 0:25:03.080 --> 0:25:07.160 is precise mathematically and physically, meaning you do have equations 0:25:07.240 --> 0:25:10.200 right written there, they apply every time, right, it's not like, oh, 0:25:10.240 --> 0:25:12.760 you use this or use that measurement or no measurement. No, 0:25:12.880 --> 0:25:16.080 it's precise, okay, And it's precise physically gives you a 0:25:16.080 --> 0:25:18.800 picture of what's going on, which is exactly how it 0:25:19.000 --> 0:25:21.640 was in the classical you know, when we're thinking about 0:25:21.640 --> 0:25:24.080 classical physics, and one of the you know, the marriage 0:25:24.119 --> 0:25:26.280 is that you can visualize. Okay. So but if you 0:25:26.320 --> 0:25:29.560 do have this theory and there are crazy things about it, 0:25:29.760 --> 0:25:33.880 you know how to which questions are needed? Right? Which 0:25:34.000 --> 0:25:38.240 questions are really the ones that we should focus on? Okay? 0:25:38.280 --> 0:25:43.240 So one question is where is this absolute ansertainty coming from? 0:25:43.560 --> 0:25:47.080 Another question, right, is what about the fact the way 0:25:47.200 --> 0:25:50.560 function is a function of all the configuration. There is 0:25:50.600 --> 0:25:53.159 a sense in which you may think that, you know, 0:25:53.200 --> 0:25:57.920 bombing mechanics removes all the romance from from physics, and 0:25:57.960 --> 0:26:00.800 that I think that's you know, a merriage romance. I 0:26:00.800 --> 0:26:04.119 would say, removes all the headaches the head Oh yeah, exactly. 0:26:04.119 --> 0:26:05.760 I mean to me, it removes all the headaches. But 0:26:05.800 --> 0:26:08.080 some people, you know, they think of that, Oh yeah, 0:26:08.119 --> 0:26:11.080 but I mean the observer, you know, gains again, right, 0:26:11.200 --> 0:26:14.720 the center of the attention. I'm not sympathetic at all 0:26:14.920 --> 0:26:17.240 about this kind of talk, but I mean some people 0:26:17.560 --> 0:26:21.320 are attracted by the craziness, right, and so when they 0:26:21.359 --> 0:26:24.480 hear about Bowman mechanics, they think, oh, what is the 0:26:24.520 --> 0:26:27.520 all the fun? What is this? I mean, physics is fun, 0:26:27.600 --> 0:26:30.800 but maybe in a different way. I'm sympathetic to that, 0:26:30.880 --> 0:26:33.119 because I think we want physics to teach us the 0:26:33.119 --> 0:26:35.639 truth of the universe, and we hope in our hearts 0:26:35.640 --> 0:26:37.960 somehow the truth of the universe is not what we 0:26:38.040 --> 0:26:40.520 imagine that we're gonna be learning something that requires some 0:26:40.560 --> 0:26:43.199 sort of like mental revolution to be like, wow, the 0:26:43.320 --> 0:26:45.800 universe is so weird and different from what we imagine. 0:26:45.840 --> 0:26:48.080 And so if you're just telling me, know, the universe 0:26:48.200 --> 0:26:50.600 at the tiny scale, it's just a tiny little bunch 0:26:50.600 --> 0:26:52.240 of baseballs, the way it is sort of like at 0:26:52.280 --> 0:26:55.119 the atomic scale and the macroscopic scale and the scale 0:26:55.119 --> 0:26:57.520 of planets and stars, then yeah, I guess that does 0:26:57.600 --> 0:26:59.800 remove a little bit of the mystery. But you know what, 0:26:59.840 --> 0:27:02.199 I was struggling to learn quantum mechanics and absorb it 0:27:02.240 --> 0:27:05.480 intuitively as a college student. The thing that really got 0:27:05.520 --> 0:27:08.400 me over the hump were these bells, theorems, and these 0:27:08.440 --> 0:27:12.400 bells and equalities that really seemed like definitive proof that 0:27:12.520 --> 0:27:15.959 quantum mechanics was random. And we have these experiments and 0:27:16.200 --> 0:27:19.880 very clever people have shown that there are these correlations 0:27:19.960 --> 0:27:24.840 among entangled particles that simply cannot happen if quantum mechanics 0:27:25.040 --> 0:27:28.879 was not fundamentally random that you can't like secretly hide 0:27:28.920 --> 0:27:31.440 all the information that it can't be the things are 0:27:31.480 --> 0:27:33.399 really just one way or not the other way that 0:27:33.560 --> 0:27:36.399 you know before you look at the electronic always was 0:27:36.600 --> 0:27:39.560 spin up in my mind. Those bells and equality really 0:27:39.560 --> 0:27:42.600 sort of like killed that possibility. Said, no, you have 0:27:42.720 --> 0:27:46.720 to accept fundamental randomness. Why don't these theorems, these bills 0:27:46.760 --> 0:27:50.040 and equalities and those experiments, why don't they kill Bonian mechanics? 0:27:50.400 --> 0:27:53.040 They did kill it for a long time. Actually, you 0:27:53.080 --> 0:27:56.560 know the first theorem that was the theory which allegedly 0:27:56.640 --> 0:27:59.880 proved that heat and variable something impossible. It was still 0:28:00.080 --> 0:28:04.720 too for Neuman in nine five or something like that, 0:28:04.840 --> 0:28:08.080 and so he basically wanted to put an end to 0:28:08.280 --> 0:28:12.960 all uh for reasons that are you know, maybe historically interesting, 0:28:13.080 --> 0:28:15.240 but I mean what he wanted to provide was a 0:28:15.359 --> 0:28:18.679 proof and mathematical proof that you cannot do better than 0:28:18.800 --> 0:28:21.840 quantum theory. So that was just like kind of you know, oh, 0:28:21.880 --> 0:28:24.000 we all would like to have a pictorial view of 0:28:24.119 --> 0:28:28.159 visualized visualize about theory, right, but we cannot. That's what 0:28:28.280 --> 0:28:31.480 he wanted to prove, and so he went by contradiction. Okay, 0:28:31.520 --> 0:28:34.439 so he said, Okay, let's pretend for a second that 0:28:34.600 --> 0:28:37.639 we can complete quantum mechanics. Let's pretend for a second 0:28:37.640 --> 0:28:41.280 that we can add these hidden variables right to the theory. 0:28:41.520 --> 0:28:43.440 The theory is not complete, right, it is, there are 0:28:43.480 --> 0:28:46.480 these even variables. At first, their hidden for them in 0:28:46.480 --> 0:28:49.200 the sense that quantum theory doesn't specify what they are. 0:28:49.440 --> 0:28:51.440 And so he said, okay, let's pretend let's start with 0:28:51.480 --> 0:28:54.560 this theory, let's work it out, let's work the consequences out. 0:28:54.680 --> 0:28:58.160 And what he obtained was that there is some sort 0:28:58.200 --> 0:29:02.040 of a contradiction, like five is greater than seven. I mean, 0:29:02.040 --> 0:29:03.440 it's not really the case, but I mean you can 0:29:03.480 --> 0:29:05.960 imagine something like that. Okay. So he said, okay, what 0:29:06.000 --> 0:29:08.680 are the assumptions? I mean the reasonable assumption. So the 0:29:08.720 --> 0:29:12.560 only assumption that so we had reasonable assumption, we started 0:29:12.560 --> 0:29:15.120 from this hidden variable theory, we get contradictions. So the 0:29:15.160 --> 0:29:17.719 only way out is just to say there are no 0:29:17.800 --> 0:29:20.840 hidden variables. The quantum world is weird. For those of 0:29:20.840 --> 0:29:22.400 you who don't know of Annoyingment is one of the 0:29:22.400 --> 0:29:25.680 great mathematical geniuses of the century and really credited with 0:29:25.800 --> 0:29:30.120 like pulling together the mathematics of modern quantum theory, and 0:29:30.160 --> 0:29:32.720 so when he said something, people tended to listen, and 0:29:32.840 --> 0:29:34.680 you know, it was sort of difficult to stand up 0:29:34.680 --> 0:29:36.800 to Vannyman. You know, back in the forties when he 0:29:36.800 --> 0:29:39.480 was in his hey day, he was very influential exactly. 0:29:39.520 --> 0:29:42.240 I mean, there is actually something normal. It's not like 0:29:42.480 --> 0:29:45.120 you can charge these people to have listened and just 0:29:45.880 --> 0:29:48.440 relied on the authority. It was just like kind of normous. 0:29:48.480 --> 0:29:50.560 It's not for Noyman process theory. I mean, there's not 0:29:50.640 --> 0:29:53.160 much of a reason to suspect that he was wrong. 0:29:53.400 --> 0:29:57.640 But he was wrong because he assumed something, which is 0:29:57.680 --> 0:30:01.120 the start that assumption of quantum theory. The experiment doesn't 0:30:01.160 --> 0:30:05.200 really change the system, Okay, The interaction is small enough 0:30:05.640 --> 0:30:08.040 that the property that you're trying to measure is left 0:30:08.280 --> 0:30:11.520 the same. Okay, like I was talking about before, right, 0:30:11.520 --> 0:30:14.120 I do believe I have a fever. Say, okay, I 0:30:14.160 --> 0:30:17.040 want to measure my temperature and making an experiment, put 0:30:17.040 --> 0:30:19.840 the thermometer under my arm. Wait a second, wait for 0:30:19.880 --> 0:30:22.640 the interaction. Than the mercury or whatever, the gallium or 0:30:22.640 --> 0:30:26.440 whatever it is, expands and it gives me the temperature. Okay, 0:30:26.520 --> 0:30:29.520 So but the temperature that I read it's not really 0:30:29.640 --> 0:30:33.600 my temperature before I actually put the thermometer under my army. 0:30:33.600 --> 0:30:41.280 It's actually the equilibrium temperature between the thermometermy and me. Okay, so, 0:30:41.360 --> 0:30:43.440 but what I read is we forget about this all 0:30:43.480 --> 0:30:45.560 the time because we believe that, I mean, this is 0:30:45.560 --> 0:30:47.720 the property of the thermometer, which was the thermometer in 0:30:47.800 --> 0:30:50.560 such a way that it doesn't affect too much that 0:30:50.600 --> 0:30:53.320 the equilibrium temperature is really close to my original temperature. 0:30:53.400 --> 0:30:56.000 So you're saying that, for example, when you measure your temperature, 0:30:56.080 --> 0:30:59.520 you actually measure slightly lower temperature than your actual temperature 0:30:59.560 --> 0:31:02.120 because the thermometer is slightly cooler than you and you 0:31:02.160 --> 0:31:04.320 guys have come into equilibrium, and it's sort of like 0:31:04.480 --> 0:31:06.360 putting a tiny little piece of ice on you and 0:31:06.400 --> 0:31:08.520 it's cooled you down a little bit. And in the 0:31:08.560 --> 0:31:11.040 same way, you need to take that into account. And 0:31:11.160 --> 0:31:14.920 van Neuman ignored the impact of the measurement on the 0:31:14.960 --> 0:31:17.760 system when he was making all of his calculations and 0:31:17.920 --> 0:31:20.640 proof that quantum mechanics had to be random, that you 0:31:20.640 --> 0:31:24.160 couldn't have any hidden variables. Right, It's actually worse than that, 0:31:24.240 --> 0:31:26.240 because I mean, this is a general assumption that we 0:31:26.280 --> 0:31:28.520 all make when you're doing quantum theory, right, we do 0:31:28.600 --> 0:31:32.760 assume that I mean the operators represent properties. The problem 0:31:32.800 --> 0:31:36.480 is that most of the time the experiments are such 0:31:36.560 --> 0:31:40.120 that they perturbed the system so much that they don't 0:31:40.160 --> 0:31:43.520 measure anything about the system. They tell you something about 0:31:43.520 --> 0:31:46.360 the interaction. Think about you want to know where the 0:31:46.360 --> 0:31:49.640 table is, Okay, so you switch on the light. Basically 0:31:49.680 --> 0:31:52.640 what happens you hit the table surface with photons, the 0:31:52.680 --> 0:31:56.200 photos going to your retina, and the retina records the result. Right, 0:31:56.280 --> 0:31:59.400 but I mean the photo world bounce back, but also 0:31:59.440 --> 0:32:02.880 the table ricoisly to bit. You forget about that, okay, 0:32:02.960 --> 0:32:07.240 because the mass and blah blah blah. Okay, it's much bigger. However, instead, 0:32:07.240 --> 0:32:09.320 if you instead of willing to try and find the 0:32:09.320 --> 0:32:11.000 position of the table, you want to try and find 0:32:11.000 --> 0:32:13.760 the position of an electron. Okay, you switch on the light. 0:32:13.920 --> 0:32:17.200 The photon hits the electron, and the electron goes. So 0:32:17.240 --> 0:32:19.800 what you measure the electron is going to click somewhere 0:32:19.840 --> 0:32:22.720 in some detectors somewhere, So the position what you're measuring 0:32:22.840 --> 0:32:25.240 is not the position of the electron before, it's the 0:32:25.320 --> 0:32:29.120 position afterwards, Okay, which is totally fine, but I mean 0:32:29.320 --> 0:32:32.360 what is tricky and sometimes what you want is that 0:32:32.560 --> 0:32:35.960 not What for no, Himan actually proved was not that 0:32:36.040 --> 0:32:39.520 hidden variables are impossible, but that he proved that not 0:32:39.640 --> 0:32:44.800 all experiments are actually measurement. So all these certain experiments 0:32:44.800 --> 0:32:49.920 are able to measure, namely those experiments where the interaction 0:32:50.000 --> 0:32:52.800 is not that high to destroy the system or perturbit 0:32:52.880 --> 0:32:55.520 too much. And how does that connect with hidden variables? 0:32:55.560 --> 0:32:57.520 Like I get that he's showing that you can only 0:32:57.560 --> 0:33:00.160 make a measurement if you're making it very small, all 0:33:00.200 --> 0:33:03.520 negligible interaction on the system, that you're extracting information from 0:33:03.520 --> 0:33:05.680 what happened before he measured it. How does that connect 0:33:05.720 --> 0:33:08.680 to the question of whether quantum mechanics is really random 0:33:08.880 --> 0:33:11.240 or whether there's sort of hidden information in there that 0:33:11.280 --> 0:33:13.840 controls what's happening. It doesn't have much to do with 0:33:13.920 --> 0:33:16.840 him invariables. That for sure. His theorem was supposed to 0:33:16.880 --> 0:33:20.000 be showing that he did invariables are impossible, Okay, But 0:33:20.080 --> 0:33:22.440 he didn't show that because he had this assumption in it. 0:33:22.680 --> 0:33:25.880 He came out with the contradiction because he was assuming 0:33:25.960 --> 0:33:28.360 this and so he was assuming that there are properties 0:33:28.360 --> 0:33:32.440 and these properties have actually weird behavior. So he set 0:33:32.480 --> 0:33:35.360 out to prove that hidden variables couldn't exist, and he 0:33:35.400 --> 0:33:38.600 did by contradiction, but instead of a false assumption into 0:33:38.720 --> 0:33:41.280 his proof, which is the thing that led to the contradiction. 0:33:41.560 --> 0:33:44.840 So his conclusion about hiddenvariables was therefore invalid because the 0:33:44.840 --> 0:33:48.080 contradiction came from somewhere else. And then this stood for decades. Right, 0:33:48.120 --> 0:33:50.720 people thought, oh no, him improved, the quantum mechanics must 0:33:50.720 --> 0:33:54.680 be random, so this the burglary theory, This, this deterministic 0:33:54.880 --> 0:33:57.520 idea of quantum mechanics, We shouldn't even think about that. 0:33:57.840 --> 0:33:59.880 And then what happened? When did people realize, oh, hold, 0:34:00.040 --> 0:34:03.280 the second pandomen was wrong and it's possible to have 0:34:03.360 --> 0:34:06.560 determinist e quantum mechanics. Yeah, well, some people actually figured 0:34:06.600 --> 0:34:09.799 this out immediately, but we're ignored either because they were 0:34:10.080 --> 0:34:13.040 you know, not very well known figure, or because they 0:34:13.080 --> 0:34:16.160 didn't really want to batter. I mean, according to some people, 0:34:16.480 --> 0:34:20.160 did Einstein figured this out immediately, but he didn't bother 0:34:20.320 --> 0:34:23.080 to reply. And it is also true that the original 0:34:23.080 --> 0:34:27.720 proof of phen nomen had other issues, which, however, where 0:34:28.239 --> 0:34:31.040 you know, taking care of in proofs that came later. 0:34:31.120 --> 0:34:33.160 But the person who actually figured this out was Bell 0:34:33.760 --> 0:34:37.120 John Bell, who actually came back to this for no 0:34:37.200 --> 0:34:41.120 human proof and figure out where he was wrong, namely 0:34:41.400 --> 0:34:45.719 the assumption that operators necessarily mean you can understand experiments 0:34:45.760 --> 0:34:48.640 always as measurement, which is not necessarily the case. So 0:34:48.680 --> 0:34:51.560 the same Bell who is responsible for most people thinking 0:34:51.640 --> 0:34:54.280 that equantum mechanics has to be random because he showed 0:34:54.320 --> 0:34:57.600 these crazy inequalities, is the one who also revealed that 0:34:57.719 --> 0:35:01.120 no Eman was wrong improving the quantum exist random. So 0:35:01.200 --> 0:35:03.040 this Bell guy had a pretty big role to play 0:35:03.040 --> 0:35:05.960 in our understanding one of mechanics. Yes, yes, and I mean. 0:35:06.040 --> 0:35:07.879 And also it is the case that he was often 0:35:07.960 --> 0:35:11.640 misunderstood for many years, even if he clearly wrote down 0:35:11.719 --> 0:35:14.719 what he was trying to prove. So I mean indeed 0:35:15.040 --> 0:35:18.360 he was writing about for Annoyman's proven very shortly after 0:35:18.560 --> 0:35:22.359 he came up with his own belt inequality. So he 0:35:22.400 --> 0:35:25.640 did try to provide a didn't variable theory. So he 0:35:26.040 --> 0:35:28.240 was trying to do the same as for Annoyman and say, okay, 0:35:28.320 --> 0:35:30.000 so if we do have it, this is it an 0:35:30.000 --> 0:35:32.360 a variable? Here? What do we get? There is a 0:35:32.400 --> 0:35:34.680 sense in which you can take as you were doing 0:35:34.719 --> 0:35:38.640 at the beginning, right, he's inequality, just like a different 0:35:38.719 --> 0:35:43.080 variety of impossibility proof against the invariable. But actually, as 0:35:43.560 --> 0:35:46.160 many people would say, even if there is a sense 0:35:46.200 --> 0:35:49.480 in which is it's controversial, I mean it's it's controversial 0:35:49.480 --> 0:35:52.080 whether he actually proved it. What it's not controversially is 0:35:52.120 --> 0:35:55.760 what he thought, Namely, he thought to have proven that 0:35:56.160 --> 0:35:57.920 at the end of the name, if you have a 0:35:57.960 --> 0:36:00.479 theory which respects the prediction of quantum kind of extent, 0:36:00.600 --> 0:36:02.640 this theory has to be non no com right, So 0:36:02.719 --> 0:36:05.000 let's unpack what that means for a moment. Because bells 0:36:05.000 --> 0:36:07.800 inequality tells us that the universe has to be random, 0:36:07.800 --> 0:36:10.160 there can't be any hidden variables. But it turns out 0:36:10.160 --> 0:36:12.840 there's a caveat. That's only true if you're talking about 0:36:12.920 --> 0:36:17.800 so called local information, right, and information which is accessible 0:36:17.840 --> 0:36:20.680 to somebody like in their immediate environment. You know, like 0:36:20.800 --> 0:36:23.840 I can know what's near me, I can measure something nearby, 0:36:23.920 --> 0:36:26.960 but I don't know anything about what's happening in Andromeda 0:36:27.160 --> 0:36:30.360 right now because this sort of limited passage of information. 0:36:30.719 --> 0:36:34.120 And I want to talk more about entanglement and locality, 0:36:34.160 --> 0:36:51.560 but first let's take another quick break. Okay, we're back 0:36:51.600 --> 0:36:55.080 and we are talking about whether quantum mechanics is what 0:36:55.160 --> 0:36:58.600 we call local. We know that there's a limit on 0:36:58.800 --> 0:37:02.200 how fast in formation can move, that there's this speed 0:37:02.239 --> 0:37:05.880 limit of information in the universe, and that information cannot 0:37:05.920 --> 0:37:09.799 move instantaneously. But this gets confusing when we talk about 0:37:10.000 --> 0:37:14.040 entangled particles. You create two electrons so that they have 0:37:14.120 --> 0:37:17.240 to have opposite spin, but you don't know which electron 0:37:17.280 --> 0:37:19.560 has spin up and which one is spinned down. But 0:37:19.600 --> 0:37:22.000 as soon as you measure one to be spin up, 0:37:22.040 --> 0:37:25.600 for example, you know instantaneously that the other one has 0:37:25.640 --> 0:37:29.120 to be spinned down. And that seems sort of nonlocal 0:37:29.200 --> 0:37:31.600 because the particles can be entangled, but they can also 0:37:31.640 --> 0:37:35.040 be really far apart. So all of a sudden, when 0:37:35.080 --> 0:37:37.520 you measure the spin of one particle, the other one, 0:37:37.560 --> 0:37:41.280 which is many many kilometers or maybe light years away, 0:37:41.400 --> 0:37:46.320 instantaneously collapses to have the other possibility. So I would 0:37:46.320 --> 0:37:48.879 put it slightly differently in the sense that I would 0:37:48.880 --> 0:37:51.719 say that in general, what Bell proofed is that you 0:37:51.800 --> 0:37:55.120 do have no locality. In general, at the beginning particle 0:37:55.200 --> 0:37:58.759 one didn't have any spin property because of the entire state. 0:37:59.000 --> 0:38:02.560 When it's measured. Instead, oh, it turns up up so 0:38:02.680 --> 0:38:05.799 and the other immediately down. And the issue there, of course, 0:38:05.880 --> 0:38:08.120 is that these things can be separated. Right, so if 0:38:08.160 --> 0:38:11.359 these two particles, they have to have opposite spins, and 0:38:11.480 --> 0:38:14.480 classical or in the traditional equantum mechanics tells us that 0:38:15.000 --> 0:38:17.240 both of them have the possibility to be up and down. 0:38:17.719 --> 0:38:19.680 And so when you measure one of them and it 0:38:19.800 --> 0:38:22.640 becomes up, then the other one, now hundreds of miles 0:38:22.640 --> 0:38:26.759 away or thousands of miles away, somehow instantaneously goes from 0:38:26.800 --> 0:38:29.960 being up or down to only being down. And that's 0:38:29.960 --> 0:38:32.960 this question of nonlocality, right, how does the information get 0:38:33.160 --> 0:38:36.840 from one particle, you know, to the other particle faster 0:38:36.960 --> 0:38:39.239 than the speed of light. Yes, that's a problem. That's 0:38:39.239 --> 0:38:43.320 something that the scars and regarded as a non starter. 0:38:43.680 --> 0:38:46.080 That was just like thinking about, I mean, that's one 0:38:46.120 --> 0:38:50.160 possibility and the other possibilities instead that they really had 0:38:50.200 --> 0:38:54.480 a property or spin since the beginning. Right, So you 0:38:54.560 --> 0:38:57.239 measure spin up because the first guy always had spin 0:38:57.360 --> 0:39:02.160 up from the start, okay, And so they don't actually talk, right, 0:39:02.280 --> 0:39:04.280 they were prepared and up and down and you detect 0:39:04.360 --> 0:39:06.799 them up and down. And that's this hidden variables interpretation 0:39:06.840 --> 0:39:09.400 that they always are something. It's just you don't know 0:39:09.440 --> 0:39:11.160 about it. It's sort of hidden from you until you 0:39:11.200 --> 0:39:13.839 measure it. But that there's no like actual uncertainty. It's 0:39:13.840 --> 0:39:16.799 not like there's the particles actually in up and down 0:39:16.880 --> 0:39:20.000 until you measure it. And so that's this problem with nonlocality, right, 0:39:20.040 --> 0:39:23.799 And you're saying, einstein collaborators were suggesting this is ridiculous 0:39:24.000 --> 0:39:27.560 because it requires a theory that's nonlocal, that somehow these 0:39:27.560 --> 0:39:29.920 things have to you know, coordinate to make sure that 0:39:29.920 --> 0:39:32.960 they're always opposite spins. And so what did Bell showed? 0:39:32.960 --> 0:39:35.520 Bell showed that every theory of quantum mechanics has to 0:39:35.560 --> 0:39:39.200 be nonlocal, Yes, because I mean he started off with 0:39:39.360 --> 0:39:43.960 a theory like that and he predicts inequality, and so 0:39:44.000 --> 0:39:46.799 they eat in variables. You have to imagine something like this, 0:39:47.080 --> 0:39:51.160 so you have quantum mechanics. Quantum mechanics implies that there 0:39:51.160 --> 0:39:54.040 has to be eating variables. So one of the main 0:39:54.080 --> 0:39:58.440 objections people might have to this theory of deterministic particles 0:39:58.480 --> 0:40:01.400 being guided by the way function information is actually there, 0:40:01.680 --> 0:40:04.200 it's just that we don't know it sometimes is that 0:40:04.239 --> 0:40:06.720 we thought that quantum mechanics have to be random because 0:40:06.800 --> 0:40:09.600 of these arguments by Bell and these experiments that showed 0:40:09.920 --> 0:40:13.360 that you couldn't explain these experiments using some hidden variables. 0:40:13.360 --> 0:40:15.920 But it turns out then you couldn't explain those experiments 0:40:16.000 --> 0:40:19.360 using local hidden variables, but you can explain those experiments 0:40:19.440 --> 0:40:23.440 using non local hidden variables. So Bonian mechanics works and 0:40:23.560 --> 0:40:28.160 is consistent with experiments if you have nonlocality, this idea 0:40:28.200 --> 0:40:30.480 that particles that are not in the same place, that 0:40:30.560 --> 0:40:33.520 are not near each other, can somehow you know, communicate 0:40:33.680 --> 0:40:37.480 or coordinate their arrangements. And you might think, well, that's crazy, 0:40:37.560 --> 0:40:40.239 that it's bonkers, how could that be possible? And that 0:40:40.680 --> 0:40:43.000 seems like a pretty big objection, But I think, as 0:40:43.040 --> 0:40:45.279 you're saying, Bell showed that this is actually true and 0:40:45.280 --> 0:40:49.440 required for all theories of quantum mechanics, not just Bomian mechanics, 0:40:49.719 --> 0:40:52.520 And so it's not really a strike against Bomian mechanics 0:40:52.560 --> 0:40:56.360 to say that requires non local information. Yes, that's true, 0:40:56.400 --> 0:40:59.040 because I mean he did prove his inequality. And if 0:40:59.040 --> 0:41:02.359 you if right, then down in the in the appropriate way, 0:41:02.400 --> 0:41:05.080 you will see that the hidden variable is just a 0:41:05.160 --> 0:41:08.200 passage in the deduction, but it's actually something that you 0:41:08.280 --> 0:41:13.399 don't require so that arguably what's going on is that 0:41:13.560 --> 0:41:16.400 every single theory that has the same predictions fantum mechanics 0:41:16.600 --> 0:41:20.440 will turn out to be non local. But doesn't nonlocality 0:41:20.600 --> 0:41:24.000 seems sort of crazy. I mean, special relativity tells us 0:41:24.160 --> 0:41:26.920 that information takes time to propagate through the universe. That 0:41:27.040 --> 0:41:30.200 what's happening in Andromeda can't influence me right now because 0:41:30.239 --> 0:41:33.080 I'm outside of its light cone. So if you're telling 0:41:33.080 --> 0:41:35.600 me that not only does Bonian mechanics, which seems like 0:41:35.600 --> 0:41:40.160 a beautiful description of the universe and nicely deterministic, require nonlocality, 0:41:40.200 --> 0:41:43.319 but all theories of econom mechanics require nonlocality, how do 0:41:43.360 --> 0:41:45.040 I then accept that? How do I think about the 0:41:45.120 --> 0:41:47.840 universe as nonlocal? Does it mean that every particle in 0:41:47.880 --> 0:41:51.799 Andromeda potentially can influence me right now? Yeah? Okay, so 0:41:51.840 --> 0:41:54.160 that's the craziness, right. So that's a good thing about 0:41:54.160 --> 0:41:57.440 Bona mechanics because in this theory the non locality is obvious. 0:41:57.480 --> 0:41:59.799 It's clear right there in the wave functions. So then 0:41:59.800 --> 0:42:03.040 that thing that we need to do as physicist is 0:42:03.239 --> 0:42:07.239 to investigate how it's possible for a theory like that 0:42:07.760 --> 0:42:10.960 to be compatible with relativity theory, right, so we just 0:42:11.040 --> 0:42:13.800 give access to the right questions again before I actually 0:42:13.840 --> 0:42:15.719 talk a little bit about that. I mean, so you 0:42:15.760 --> 0:42:19.000 don't really have to go into the interpretation and show 0:42:19.080 --> 0:42:21.600 that all the other interpretation are no local. Just think 0:42:21.600 --> 0:42:26.000 about the regular theory, okay, with the collapse. When you 0:42:26.040 --> 0:42:29.319 do have the collapse, the collapse is no local, right, 0:42:29.360 --> 0:42:32.640 I mean, think about the original EPR argument. Right, how 0:42:32.680 --> 0:42:36.200 do you explain the compa relation over there? It's no local, right, 0:42:36.520 --> 0:42:38.879 You measure one, the other has to tell the first 0:42:38.960 --> 0:42:40.759 one has to tell the other one. Right, that's no 0:42:40.840 --> 0:42:43.880 locality right there. It's not a problem of the hidden variables. 0:42:44.160 --> 0:42:46.440 I mean the regular I mean, the textbook theory has 0:42:46.520 --> 0:42:52.080 it right there. Indeed, Heisenberg accepted that, yes, there are 0:42:52.120 --> 0:42:55.000 some lectures that I forgot the year the precise here 0:42:55.320 --> 0:42:58.880 in which he talks about exactly this. Right, the collapse 0:42:59.000 --> 0:43:03.200 is no local, But then he says it doesn't contradict relativity. 0:43:03.280 --> 0:43:06.520 He did really take it seriously that much because he 0:43:06.680 --> 0:43:09.640 thought that you kind of use the non locality of 0:43:09.680 --> 0:43:14.200 the collapse transfer information. So if you think of relativity 0:43:14.200 --> 0:43:17.040 as a theory of sicknals, there is not I mean, 0:43:17.080 --> 0:43:20.239 you can't get around, there's no locality, right, And so 0:43:20.320 --> 0:43:22.719 for our listeners who are curious, it does seem like 0:43:22.760 --> 0:43:25.920 there's some weird nonlocal features of quantum mechanics, but it 0:43:26.080 --> 0:43:29.520 is not possible to use that nonlocality to send information 0:43:29.600 --> 0:43:31.680 faster than the speed of light. And Jorge and I 0:43:31.719 --> 0:43:33.759 did a whole podcast on that, so check that out 0:43:33.760 --> 0:43:35.680 in detail. We don't have time to get into all 0:43:35.719 --> 0:43:37.640 of that today, but if you're curious about why you 0:43:37.680 --> 0:43:40.080 can't send information fast in the speed of light using 0:43:40.160 --> 0:43:43.240 quantum entanglement, we did cover that in the whole podcast episode. 0:43:43.400 --> 0:43:45.440 All right, So this is really fascinating and I don't 0:43:45.440 --> 0:43:46.759 want to use too much more of your time, so 0:43:46.800 --> 0:43:49.520 I just want to ask you if Bowman mechanics, you know, 0:43:49.719 --> 0:43:52.640 is a nice, beautiful picture of the universe and explains 0:43:52.680 --> 0:43:55.359 all the experiments that we have and doesn't require us 0:43:55.400 --> 0:43:59.920 to accept some strange, alien uncertainty and randomness that's counterintuited 0:44:00.320 --> 0:44:04.800 and only requires the acceptance of this concept of nonlocality, 0:44:04.920 --> 0:44:08.160 which already is present in all other quantum theories. Then 0:44:08.280 --> 0:44:10.520 why isn't it the dominant quantum theory? What are the 0:44:10.520 --> 0:44:13.239 objections against it? Is? It's still sort of like historical 0:44:13.280 --> 0:44:16.319 inertia because von Neuman didn't like it, or there you know, 0:44:16.400 --> 0:44:18.960 real philosophical objections to it. So I mean, I think 0:44:19.000 --> 0:44:21.160 that part of the problem has to do with the 0:44:21.200 --> 0:44:23.920 fact that historically it was blocked. I mean there is 0:44:23.960 --> 0:44:27.520 all this, you know, historical accidents that happened one after 0:44:27.600 --> 0:44:29.799 the other. I mean the first bomb was you know, 0:44:30.280 --> 0:44:34.040 ostracized for various reasons, and then for Neuman contributed to this, 0:44:34.600 --> 0:44:37.120 there seemed to be no real reason to reject this 0:44:37.239 --> 0:44:40.120 theory from from a rational point of view. I mean, 0:44:40.160 --> 0:44:43.520 it provides a clear mathematical picture. It's a clear physical 0:44:43.560 --> 0:44:46.200 picture as well. You do have to accept no locality, 0:44:46.239 --> 0:44:48.400 as you said, but I mean it's something that we 0:44:48.440 --> 0:44:52.480 have to deal with. Some people sometimes mentioned that, oh, 0:44:52.520 --> 0:44:56.200 it's not testable in the sense that probably the prediction 0:44:56.239 --> 0:45:00.000 of the Boomian mechanics are the same as quantum theory. 0:45:00.000 --> 0:45:02.720 That's not a good objection for a variety of reason. First, 0:45:02.880 --> 0:45:05.600 because I mean, you have a piece of evidence. You 0:45:05.640 --> 0:45:08.120 have two theories, right, and so which one of the 0:45:08.120 --> 0:45:11.560 theories the evidence confirming, assuming that you can confirm a 0:45:11.600 --> 0:45:14.439 theory the first? Okay, so who came first? The brawl 0:45:14.719 --> 0:45:19.400 nine twenty three. Right, uh, and so because no, no, no, no, 0:45:19.440 --> 0:45:22.120 but it's simpler, right, you come to mechanics is simpler, 0:45:22.239 --> 0:45:24.759 that's just one equation, but the mechanics has two equations, 0:45:25.080 --> 0:45:28.440 one equation with two evolution equation. Okay, so what about 0:45:28.480 --> 0:45:31.200 time of light? You have particle physicists, right, you measure 0:45:31.239 --> 0:45:33.359 time of flight, You measure where the particle how long 0:45:33.400 --> 0:45:35.319 they take to go from here to there? But there 0:45:35.400 --> 0:45:37.239 is no time open it. And so what are this 0:45:37.320 --> 0:45:40.080 time of light results? Well, I mean the drugular quantum 0:45:40.120 --> 0:45:43.120 theory have resorts to this kind of approximation. Right. If 0:45:43.120 --> 0:45:45.480 you approximate the time measurement in one way or in 0:45:45.480 --> 0:45:49.920 another way, you get different distribution of results. Booming mechanics 0:45:49.960 --> 0:45:52.759 gives you uh, you know their particles, right, So you 0:45:52.800 --> 0:45:55.080 don't need the operators, right, you just do you use 0:45:55.160 --> 0:45:57.799 the particles trajectories and do the calculation that you would 0:45:57.840 --> 0:46:01.520 do classically, but with quantum tra actorism. And so there 0:46:01.680 --> 0:46:05.520 is the possibility of actually making an experiment. So there 0:46:05.520 --> 0:46:08.040 are some cases in which you can put yourself in 0:46:08.040 --> 0:46:10.759 a situation in which the prediction from quantum theory are 0:46:10.840 --> 0:46:15.799 different from boom mechanics. This can happen because you know, 0:46:16.040 --> 0:46:20.799 quantum mechanics is not precise, some bigues in disrespect, so 0:46:20.880 --> 0:46:23.560 you can test out. So there is a strong sense 0:46:23.840 --> 0:46:27.880 in which you can, you know, falsify quantum theory or 0:46:28.040 --> 0:46:32.040 quantum mechanics. So even if your physicists are usually strong 0:46:32.080 --> 0:46:37.000 about this undetectability business, but I mean, no, you can detect. So, 0:46:37.040 --> 0:46:39.600 I mean, I really don't understand that much about the 0:46:39.640 --> 0:46:44.799 reasons why quantum mechanics hasn't been taken more seriously by physicists. 0:46:45.680 --> 0:46:48.719 And I hope the situation we've changed. Well, what it 0:46:48.800 --> 0:46:51.000 might require for to change is maybe for us to 0:46:51.440 --> 0:46:54.800 meet alien intelligence and talk to them about quantum mechanics 0:46:54.840 --> 0:46:57.400 and you know, maybe their way in and will say, sorry, folks, 0:46:57.480 --> 0:46:59.520 we think it's many worlds or no, what you call 0:46:59.600 --> 0:47:02.560 booming mechanics is what makes most sense to us. So 0:47:02.719 --> 0:47:04.399 on the topic, let me ask you are totally off 0:47:04.400 --> 0:47:06.640 the wall question, what do you think are the chances 0:47:06.680 --> 0:47:09.680 of that that if we meet alien intelligence that they 0:47:09.719 --> 0:47:12.880 will have sort of similar concepts about the universe. I mean, 0:47:12.960 --> 0:47:14.960 it's really another way to ask the question, do you 0:47:14.960 --> 0:47:18.120 think what we're doing here are playing games inside our 0:47:18.120 --> 0:47:21.120 own minds? To try to tell mathematical stories about the 0:47:21.200 --> 0:47:23.319 universe it makes sense to us, or do you think 0:47:23.320 --> 0:47:26.239 we're actually probing something deep and universal which we could 0:47:26.440 --> 0:47:30.279 present without embarrassment at the first Interstellar Physics meeting after 0:47:30.280 --> 0:47:33.640 we meet the aliens. I really do hope that we 0:47:33.719 --> 0:47:37.680 can meaningfully talk about the universe, and it seems like 0:47:37.719 --> 0:47:40.400 we are actually succeeding in that right. We explained so 0:47:40.440 --> 0:47:44.440 many things since the beginning that we started doing science. No, 0:47:44.960 --> 0:47:48.440 we've made many hypothesis and constructive many theories, and some 0:47:48.560 --> 0:47:50.560 some of them were bad ideas, some of them are 0:47:50.600 --> 0:47:53.640 better ideas. I think that the fact that we are 0:47:53.719 --> 0:47:57.200 explaining so much is an indication that maybe we are 0:47:57.239 --> 0:48:02.400 onto something, but I don't know. I hope that we 0:48:02.440 --> 0:48:06.439 can contribute to the alien meeting in some way. Maybe 0:48:06.440 --> 0:48:08.640 they have their own version of bondingment and they've made 0:48:08.680 --> 0:48:10.560 their own mistakes along the way, so we can help 0:48:10.600 --> 0:48:12.960 them understand some of the things that we have learned. 0:48:13.160 --> 0:48:14.920 I hope also that when we meet the aliens, we 0:48:14.960 --> 0:48:16.799 can talk physics with them, because I hope that they 0:48:16.840 --> 0:48:19.160 are advanced and that millions of years ago they were 0:48:19.160 --> 0:48:22.120 struggling with these questions and now to them. It's child's play. 0:48:22.200 --> 0:48:25.000 But I fear honestly that everything we've learned is sort 0:48:25.040 --> 0:48:28.280 of centered in the human mind. We're asking human questions, 0:48:28.280 --> 0:48:31.279 we're telling human stories using mathematical tools that makes sense 0:48:31.320 --> 0:48:34.400 to humans, and that it might be frankly impossible to 0:48:34.400 --> 0:48:37.360 translate into this knowledge to any other intelligence. But it 0:48:37.400 --> 0:48:39.880 remains to be seen, and the universe has filled with surprises. 0:48:39.920 --> 0:48:42.600 So I look forward to having hard quantum mechanics conversations 0:48:42.719 --> 0:48:45.120 with alien physicists. All right, And with that, I'll say 0:48:45.120 --> 0:48:47.319 thank you very much for coming out a podcast and 0:48:47.360 --> 0:48:50.719 talking to us about this crazy concept of boom and mechanics. 0:48:50.840 --> 0:48:52.800 It seems to me like sort of a beautiful theory 0:48:52.880 --> 0:48:56.240 that lets us recover the sense that the universe makes sense, 0:48:56.640 --> 0:48:59.480 that these particles are flying through the air, and they 0:48:59.520 --> 0:49:02.080 have victories, and they were here and then they're there, 0:49:02.120 --> 0:49:03.920 which means that they were sort of in between in 0:49:03.960 --> 0:49:06.320 the middle. That you can still think about the universe 0:49:06.320 --> 0:49:08.759 in a way that's intuitive to you, and that you 0:49:08.800 --> 0:49:10.360 can sort of get rid of a lot of this 0:49:10.440 --> 0:49:13.359 quantum weirdness and uncertainty. In some ways, it even hangs 0:49:13.400 --> 0:49:16.400 together better than other theories, and it's a sort of 0:49:16.520 --> 0:49:19.200 unfortunate that it was cast aside for so many decades 0:49:19.239 --> 0:49:22.440 because of the mistake of eminent physicists. But we'll see 0:49:22.480 --> 0:49:25.000 what the future holds and how much progress we have 0:49:25.080 --> 0:49:27.200 to make. So thanks again very much for coming on 0:49:27.239 --> 0:49:29.279 the podcast. It was a pleasure. Thank you, Thank you 0:49:29.360 --> 0:49:39.600 very much. Thanks for listening, and remember that Daniel and 0:49:39.640 --> 0:49:42.560 Jorge explained. The Universe is a production of I Heart 0:49:42.680 --> 0:49:45.840 Radio or more podcast. For my heart Radio, visit the 0:49:45.880 --> 0:49:49.640 I heart Radio app, Apple Podcasts, or wherever you listen 0:49:49.719 --> 0:50:01.160 to your favorite shows.