Pod Insights Daniel and Kelly's Extraordinary Universe How to make sense of quantum entanglement About this episode Daniel and Kelly talk about the confusing aspects of quantum entanglement, and try to untangle the concepts.
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Transcript 11,631 words · 22 speakers
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2:36 Daniel Whiteson? Hey, everyone. It's Daniel with a quick note about my new book, which is out now. Do Aliens Speak Physics is all about how easy or hard it might be to talk to arriving aliens about physics. I think it's right up your alley, but you don't have to trust me. Here's what Seamus Blackley, creator of the Xbox, said about it. Quote, "You should buy this book. If you don't buy it for the charming, smart, funny prose, buy it for the lovely and poignant illustrations. Buy it for the wonderful imaginative daydreams about how we might meet aliens and what they'd be like. Buy it because it will gently, accidentally educate you about the history of language, translation, decryption, and the cultural impact of the writing and transmitting ideas. Not enough? Buy it for the thoughtful, clear, and genuinely entertaining grand tour of the fundamentals of math, physics, and the universality of consciousness.
3:21 Daniel Whiteson? You won't go wrong." So please, consider picking up a copy of Do Aliens Speak Physics?
3:37 Daniel Whiteson? The goal of science is to make sense of the world, to unravel the laws that control it and translate them into something that makes sense to us. But there's no guarantee that the universe runs on rules that we can understand. What if our intuition, built in a slow and large environment, doesn't equip us with ways of understanding that can be mapped to the quantum world? One of the trickiest elements of quantum mechanics is its strange randomness. We like to think that the universe follows rules that determine what happens, that at any moment, there is a true story of reality. But quantum mechanics says no. There are only probabilities until you look and then a random one is selected.
4:21 Daniel Whiteson? And if you have two quantum objects whose fates are intertwined, who have to coordinate their outcomes to follow some rule, then those outcomes are somehow determined together, even across vast distances of space, instantaneously? How does that make sense? Today, we're going to do a deep dive into quantum entanglement and try to untangle some misconceptions. Welcome to Daniel and Kelly's Extraordinary Quantum Universe.
5:01 Kelly Weinersmith? Hello, I'm Kelly Wiener-Smith. I study parasites and space, and I'm excited that I'm going to have all of my confusion about entangled particles cleared up today. I will be an expert.
5:12 Daniel Whiteson? Hi, I'm Daniel. I'm a particle physicist, and often I feel like a superposition of many Daniels.
5:19 Kelly Weinersmith? Okay, all right. Psychologist, Kelly, I'm putting on my psychology hat. What does that mean, Daniel?
5:26 Daniel Whiteson? Well, you know, the simplest way to think about it is we have so many roles in our lives, right? You know, you're a spouse, you're a parent, you're a scientist, you're an author, you're a citizen. Sometimes I feel like such different roles with conflicting needs, it almost feels like you're a different person in each context. Don't you get that way?
5:44 Kelly Weinersmith? Yeah, you forgot goat herder, but...
5:48 Daniel Whiteson? And goose lord.
5:49 Kelly Weinersmith? And goose lord. Lady of the goose, the geese, lady of the geese. Yeah, we just named our geese Jacques and Francine Gusteau. We're very excited about that.
6:00 Daniel Whiteson? And some of this is reflected in my CV, and so I have to put you on the spot, Kelly. Did you do your homework?
6:05 Kelly Weinersmith? Did I? I didn't look at your CV, no.
6:08 Daniel Whiteson? Oh, my God, you didn't look at my CV. The blank stare I just got, folks, you would be amazed.
6:13 Kelly Weinersmith? I can't believe you're asking me that.
6:17 Kelly Weinersmith? I still have dreams about forgetting to do my homework.
6:20 Daniel Whiteson? Oh, well, there you go.
6:22 Kelly Weinersmith? Yeah.
6:22 Daniel Whiteson? I'm giving you a zero on this one, but you know, to turn it in late, maybe we can give you some partial credit.
6:27 Kelly Weinersmith? I didn't think you actually expected me to go find your CV. How about you send it to me in an email?
6:33 Daniel Whiteson? Okay, I will. It's not that hard. Just Google me.
6:36 Kelly Weinersmith? All right, all right. I'll look. Here, I'm gonna make myself a note.
6:42 Kelly Weinersmith? After I herd the goats, I'll find Daniel's CV.
6:48 Daniel Whiteson? I'm second in importance to the goats. I feel so honored.
6:51 Kelly Weinersmith? Well, I might also take the geese for a swim first.
6:57 Daniel Whiteson? All right. Well, many of you out there also have multiple roles in your lives. You are podcast listeners, you are curious about science, but you are also nurses and teachers and firefighters and bankers and all sorts of stuff. We love hearing from you. So write in, tell us who you are, what you do, and how this podcast superimposes on your life.
7:15 Kelly Weinersmith? Oh, man. I never get tired of physics puns. Maybe.
7:21 Daniel Whiteson? And today, we're going to hear about something I hear about a lot from listeners who really want to understand one of the weirdest, most confounding, yet most revealing things we've learned about the universe, which is quantum entanglement and how it all works.
7:38 Kelly Weinersmith? This is a super confusing topic, I think. And it's one of those topics where I have to admit, and I think I've said this on the show before, I hear about it and I think physicists are missing something. This can't, this can't be true. But I'm sure by the end of the episode, you're going to convince me this is definitely true, and we should give more money to science to figure it out better.
8:00 Daniel Whiteson? Well, you're right, actually, because the story we're going to tell at the end is about physicists misinterpreting their own results and misunderstanding and propagating that misunderstanding for decades until we understood really what these experiments were telling us. So even physicists at the top level, we're talking about von Neumann and his colleagues, misunderstood or misrepresented what these experiments mean. So it's not easy.
8:26 Kelly Weinersmith? I'm thrilled to report that that has never happened in biology.
8:32 Daniel Whiteson? All right. Well, before we dig into quantum entanglement, I wanted to know what people out there thought about it and what they found confusing about it, to make sure that all of the quantum itches out there got scratched. So I reached out to our group of volunteers, which you are very welcome to join. Write to us, to [email protected] , and we'll add you to the volunteer question answering corps. Here is what people had to say when I asked them, what's the most confusing thing about quantum entangled particles?
9:02 Kelly Weinersmith? And I'm going to add my voice to the chorus. All of it.
9:08 Speaker 06 Particles are entangled because they are part of a system and that entangles them. And then they go off and become part of another system. And so they're entangled in another system. It's just how they would move from being entangled with one to another. It just seems arbitrary how they would do that.
9:26 Speaker 07 Speed which the information travels. Like, what's so special about two particles being formed at the same place and same time? So that like they're entangled.
9:37 Speaker 08 But probably the thing that is most confused is that it is a method for faster than light communication.
9:45 Speaker 09 I think it's confusing that if there's a collapse of quantum state on one particle, there's an instantaneous corresponding collapse on the other particle. But regardless of distance, this is a transmission of information faster than the speed of light.
10:04 Speaker 10 The most confusing part of quantum entangled particles is how we keep their states from collapsing to figure out they were entangled in the first place.
10:12 Speaker 11 I heard something recently that said entanglement could be non-traversable wormholes between particles. I'd say that's, that's really confusing.
10:21 Speaker 12 How does the universe get the information to the other particle when one of the two is measured? It's, it's just mind boggling.
10:30 Speaker 13 Well, for me, it's that there's no information transferred. So if you've got an up and a down particle and you separate them, one turns out to be up, the other one has to be down, but it's got to be more complicated than that.
10:43 Daniel Whiteson? I can't think of anything about them that is not confusing. Well, this is just about what I expected, you know, good, deep questions about how do we know the universe really is random? How do we know it wasn't actually determined in advance somehow? How does this whole thing happen across great distances? Can you use this to communicate faster than light? It is all very confusing.
11:04 Kelly Weinersmith? And we did chat on a previous episode about whether or not you can use it to communicate faster than light. And I remember that the answer is no. That's right. That's right. But, you know, let's remind everyone of all of the details and like all truly exciting explanations, we're going to start with definitions.
11:23 Daniel Whiteson? Hey, if you want to be crisp and really explain stuff, you gotta use these words that mean something. And so we have to agree on what words mean, which is why, yes, every important philosophical conversation starts with like, what do you mean by science anyway? Because words are fuzzy and slippery, right?
11:40 Kelly Weinersmith? Yeah, no, I do. I do absolutely agree. It is important. So let's start by defining random, which I know is a term that can get many statistics people very angry. If you say, I randomly picked blah, and you weren't actually random, you can see that they're like, the blood is boiling and the like, steam is about to come out of their ears. And so why are statisticians mad at me when I say I picked something randomly and it wasn't really random?
12:06 Daniel Whiteson? Yeah, and teenagers have their own definition of random. You know, like some rando on the internet. Well, it's not really random, is it? But the teenagers don't want to hear that.
12:15 Kelly Weinersmith? What teenagers don't want to hear what their parents have to say when we want to correct them and make sure they're accurate? Impossible.
12:21 Daniel Whiteson? Actually.
12:24 Daniel Whiteson? So let's distinguish true randomness from our typical experience of things we call random. So for example, we use like dice or coins when we need a random number. You're playing a game, you need a number between one and six. You don't want to chosen in advance. You roll a die. You have to decide who gets the last scoop of ice cream. You flip a coin, right? But these processes are not truly random. They're actually chaotic and they're not random because they're deterministic, which means that the initial conditions, exactly how you rolled the die or exactly how you flip the coin determines the outcome. If you did it exactly the same way twice, you would get exactly the same answer because it's following laws of physics, classical physics, which are deterministic.
13:09 Kelly Weinersmith? But you know, you're never really doing it the same way twice. So why, why are you being this way?
13:19 Daniel Whiteson? And you're right, that's almost impossible to do, maybe literally impossible to do, which is why it's a useful stand-in for random processes. When you need something unpredictable, then you use a chaotic process. And that's what these are. Coins and dice, they are chaotic. They are very, very difficult to predict because they're very sensitive to the initial conditions. We have these points and these edges on the dice so that if you toss it slightly differently, it has a chance to go left or a chance to go right. And the coin is very delicately balanced on its edge so that it's super sensitive to exactly how you flipped it and the wind conditions and if your partner is glaring at you or whatever. All these tiny details, which make it effectively impossible to predict, lets the coin and the dice do its job.
14:04 Daniel Whiteson? And we use chaos because we don't have in our normal, everyday lives access to true randomness, by which I mean something which if you ran it exactly the same way multiple times would give you different answers. A spectrum of answers determined by some probability distribution.
14:21 Kelly Weinersmith? But the good news is when I use the random number generator on my computer, I do get random numbers and the statisticians should leave me alone.
14:29 Daniel Whiteson? This is rage bait.
14:31 Kelly Weinersmith? Right, right?
14:32 Daniel Whiteson? No, wrong, unfortunately. Because how does your computer work, right? Your computer is not a quantum computer. It's a classical computer. It's deterministic. That's the best thing about the computer is that if you run the same program twice, you get the same answer. What else could it do, right? It's literally just following the rules of digital logic, which are crisp and deterministic. And so you run a random number generator on your computer. What is it doing? It generates a string of digits and it picks one for you. This is not a random string. You set the seed to the same value, you get the same series of digits. They are roughly distributed in a uniform manner between two different numbers. And so in that sense, they're useful, but they're not actually random because again,
15:17 Daniel Whiteson? the same initial conditions lead to the same string of numbers.
15:21 Kelly Weinersmith? So if you were to use a random process to create 10 numbers and a chaotic process to create 10 numbers, like how meaningfully different would your result be? P.S. are the statisticians being silly?
15:36 Daniel Whiteson? Statisticians are very silly because they also have this concept they call a random variable, which isn't random in the sense that we're talking about from a physics point of view. It's like a mapping between outcomes and numbers on the number line, which really is not random at all. And so it's a totally misnamed statisticians. Feel free to email me hate messages about this, but I will stand by this position. So your question is like, does it matter? And mostly it doesn't, which is why it takes really clever, very subtle experiments to distinguish between a universe where things really are random at the microscopic level and things are deterministic and chaotic. And we'll get into those experiments in a minute. But philosophically, it makes a
16:18 Daniel Whiteson? big difference, right? It tells you that you live in a very different universe if the laws are deterministic and if the laws are probabilistic, right? Let's start with deterministic laws. If the universe is fully deterministic, meaning that like the current setup of the universe, every particle, where it is, its velocity determines the future completely, that says something really powerful about the universe. It says the future is determined, right? What's going to happen tomorrow may be hard to calculate, may require a supercomputer, it may depend on a butterfly's wings, but in principle, there is only one possible future. And we might not be able to extract it from our limited knowledge of the current situation and our limited ability to computationally apply the laws
17:02 Daniel Whiteson? of physics. But in principle, it is determined by the current state of the universe. So that deterministic universe, like a clockwork universe, is amazing and fascinating, but also kind of scary because like, hmm, how do I fit into that? Am I just a robot following the conditions of the universe?
17:19 Kelly Weinersmith? Okay, so just to summarize real quick, if it's chaotic, then if you rewind a situation and play it forward again, you'll get the exact same result. And if it's random, then you'll rewind the situation. And even if everything about the situation stays the same, you're going to get a different result.
17:35 Daniel Whiteson? Exactly. And there's something really subtle there, which I think is often overlooked about what it means to be random, because random is not arbitrary. Right? We're not saying, look, whatever happens just happens by hap. The universe is lawless. Right? We still have laws of physics. Quantum mechanics is actually deterministic, and that's a very confusing thing to say, but hold on for a moment, is deterministic in a different way than classical physics. Classical physics says you hit the cue ball the same way, you're always going to get the same outcome. You flip the coin the same way, you're always going to get the same outcome. Quantum mechanics says you run the same experiment twice, you don't get the same outcome, but you get exactly the same probability of outcomes. So physics doesn't give up, it just retreats one step.
18:20 Daniel Whiteson? It says, I can't tell you exactly what's going to happen for any individual experiment, but I do absolutely determine the probabilities of various things happening. So some things impossible to happen, zero probability they will never happen. Other things very likely, some things very improbable. So for example, when we smashed particles together at the Large Hadron Collider, we don't know and we can't know what's going to happen for any individual collision. But we can and we do calculate the probabilities of X happening, or Y happening, or Z happening. And then we go off and we measure the rates at which those things happen. We compare them to our calculations and they agree. So quantum mechanics is not arbitrary, it's just deterministic in a different way.
19:02 Daniel Whiteson? It's like generalizing determinism, not at the individual experiment level, but at the possibilities of the outcomes.
19:09 Kelly Weinersmith? Okay. All right. I totally followed that. And so if you want to get true random numbers, do you have to be doing quantum mechanics? Or are there other ways to get random numbers?
19:21 Daniel Whiteson? Quantum mechanics is, as far as I know, the only source of true randomness in the universe. All classical physics is deterministic, right? Every classical theory depends on the initial conditions and the outcomes are totally determined by those initial conditions. And so classical physics, yeah, totally deterministic. And philosophically, this was like mind blowing for people once they understood it. Before we had quantum mechanics, they were like, oh my gosh, wow. Seems like the universe is deterministic. We are all effectively philosophical clocks, right? We're robots determined by the early universe. And you know, us being on this podcast was set in stone once we had the universe at a certain stage billions of years ago.
20:03 Kelly Weinersmith? Thank goodness.
20:03 Daniel Whiteson? And then. Quantum mechanics is actually, no, there's an important layer at which the universe is not deterministic. There's a probabilistic nature there. There's some randomness there.
20:14 Kelly Weinersmith? So the world is lucky that we ended up doing this podcast.
20:18 Daniel Whiteson? Well, it opened up a whole rabbit's hole of philosophical questions like, does that actually allow for free will? And, you know, my answer is, I'm not sure it does because the universe is not arbitrary. It doesn't open the door for like, mind-body duality, where you can have like, some non-physical mind now affecting the physical universe. It just says that there's some randomness, right? And free will is not randomness, right? When you go to choose ice cream at the store, you're making a choice for chunky monkey, right? It's not randomly decided. And so, anyway, that's a whole philosophical rabbit hole we're not gonna go down today.
20:52 Kelly Weinersmith? The chunky monkey rabbit hole.
20:55 Kelly Weinersmith? It's an important rabbit hole.
20:57 Daniel Whiteson? It's a pretty chunky rabbit hole, yes, for sure. But let's take one more step towards entanglement. So, so far, we've talked about randomness and what that means. And so let's imagine, for example, a classical coin, right? You flip it, it's hard to predict, but it is determined. Imagine now you had some quantum version, a coin which you could flip and was really random, right? It was not determined by the initial conditions. The other amazing thing about this quantum coin is that it preserves both possibilities until you look. So the classical coin, you flip it, it lands in your hand, you cover it up. But under your hand, it is heads, or it is tails, right? You just don't know
21:38 Daniel Whiteson? it yet. The quantum coin, you flip it, it's under your hand. Until you look, it has the superposition of all the possibilities. Maybe it's heads, maybe it's tails, right? So not only is quantum mechanics random, but it's also undetermined until it's measured, which is going to be an important factor in our later conversations. So that quantum coin is undetermined. And that's weird. And you can ask the same question you asked a minute ago, like, well, how different is it? Because you look, it's got an answer. How do you really know it's undetermined? How do you really know it's random? And how do you really know that it's undetermined until you look?
22:12 Kelly Weinersmith? Yeah, right. And this is where I help the whole field of physics by letting you all know, you've just got to be wrong about that. That doesn't feel like it makes any sense to me. And so go back to the drawing table and try again, guys.
22:27 Kelly Weinersmith? And gals. All right, so we are about 5% of the way through our outline and about a third of the way through our episode. I got really excited about randomness and chaos. Let's take a break, get ourselves back on track. And when we come back, Daniel will convince me that I'm wrong about all of physics.
22:50 Daniel Whiteson? Wait, so your homework is check Daniel's CV. My homework is convince Kelly that all of physics is correct. Wow, this doesn't feel like an equitable distribution of tasks.
22:59 Kelly Weinersmith? Well, you know, if physics got things right in the first place, you wouldn't have to worry about this. This is why you gotta be in biology, you know? We got it all figured out. It depends.
23:09 Daniel Whiteson? Nothing's right or wrong anyway, so.
23:11 Kelly Weinersmith? Yeah, there you go. There you go. All right, let's take that break.
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25:23 Speaker 16 Hey, it's Niall Rogers, host of Before the Moment, a Lincoln original series. I'm driving across the country, meeting some of today's most fascinating artists. We're exploring the stories before the moment that changed everything. This week, I'm joined by my friend, John Ledge. What still makes you just sit down at the piano?
25:46 Speaker 17 If you sat down at 9:00 a.m. and then at noon, you had a full song that you recorded and put in your voice recorder or you recorded at your studio. You've just created something brand new that didn't exist when you woke up. What a beautiful feeling it is. I'm always excited to write something new. I've been writing for Broadway, which has been a new challenge with new collaborators and these amazing performers who are triple threats, who can sing and dance and act and do all these amazing things. And I want to keep feeling that. And so that means not resting on my laurels, going out there and continuing to create something new.
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26:41 Kelly Weinersmith? Okay, so at the end of our last session, I dropped the bombshell that all of physics is wrong. And Daniel is going to let me know why he thinks I'm wrong. So, all right, Daniel, quantum entanglement, how can that coin that you flipped and it's in your hand, but you've covered it? How can it be both heads and tails, superimposed at the same time, but doesn't actually end up as one until you move your hand away?
27:07 Daniel Whiteson? Yeah, it's bizarre. And to really probe this, we're going to have to make this setup one step more complicated and even more counterintuitive. And so to explain this, we're going to have to make this setup a little bit more complicated. We're going to need two objects, and we're going to need them to be connected in an important way. We need their fates to be connected. And so instead of having a coin, let's imagine that we have two bags. One has a red ball in it and one has a blue ball in it. Okay, and these are just classical, normal balls. It's no big deal. And I have one and Kelly has the other. And we pick bags and we go back to our homes. I'm in California and you're in Virginia. And I look at my bag and I see that I have the blue ball in my bag. Now I instantly know that you have the red ball, right? Because we knew there was one blue and one red. And I know you have the red ball
27:51 Daniel Whiteson? because I'm applying this constraint, this condition, this requirement that there was only one blue and one red. And therefore, if I had the blue, you have to have the red. No magic at all, right? And also, no instantaneous communication of information, right? Like, I know instantly that you have the red ball. You don't know that, right? I know that. I know something about a ball that's really far away, and I know that instantly. But again, there's been no instantaneous communication of information, right?
28:20 Kelly Weinersmith? I mean, I'll be honest, Daniel, I probably peaked.
28:23 Daniel Whiteson? You are a cheater, aren't you? I knew that about you.
28:28 Kelly Weinersmith? Okay, but I totally understand the scenario you've laid out.
28:31 Daniel Whiteson? All right. Now, let's imagine the quantum version. In the quantum version, things are different. Okay, so number one, it's not determined who has the blue and the red. Like in the classical version, I had the blue one the whole time. I just didn't know it, right? In the quantum version, it's not determined. I could have the blue or the red. And so the ball is in this undetermined state. It has a probability of being red and a probability of being blue. And your ball is also has a probability of being red and a probability of being blue. But because we know there's only one blue ball, if I look inside my bag and I see the blue ball, now I know you have a red ball, right? And so then something amazing happens. My ball goes from both possibilities to being blue.
29:15 Daniel Whiteson? And at the same time, your ball goes from both possibilities to only one possibility of being red.
29:20 Kelly Weinersmith? Okay, so is the ball both blue and red? Or it's just neither until you look? What is the right way to be thinking about this?
29:31 Daniel Whiteson? Yeah, so people like to say that it's both things at the same time. Electrons can be in multiple places at the same time. I think that's confusing in a way that doesn't educate and isn't accurate because it's not true that it's in both locations at the same time or that it has both colors. It just has the probability to have both colors and it's not yet determined. Right? So it doesn't make any sense to say the ball is blue and it's red or it has both colors. It's just that it has both possibilities and we don't know yet. And the universe has not yet decided, right? And the weird thing about this is like, how can you tell, right? All I'm doing is I'm picking a bag. I'm going to California, opening up, I'm seeing it's blue. How do I know the universe didn't actually just decide when I picked the ball, which one I had and which one you had?
30:15 Daniel Whiteson? How can I tell that it was really uncertain and there really is random? And that's the crux of the question. That's what we want to know, like, what's really going on inside these bags? And of course, when we do these experiments, there are no quantum versions of balls and bags. And so we do it with particles. And we do it with particles that are constrained by laws of physics to have some opposite characteristic. So for example, you create two electrons in such a way that one has to be spin up and the other one has to be spin down to conserve angular momentum. And so when you measure one, you learn that it's spin up, you know, the other one has to be spin down. And that's just because we need a quantum property of a quantum object. And we've been talking
30:57 Daniel Whiteson? about bags and balls, but there aren't actually quantum bags and balls. And so in the real world, we do this with spin and with particles.
31:04 Kelly Weinersmith? So I think when we were talking about quantum internet, you explained some of this there. And I asked how this differs than the Schrodinger's cat example is like, is the cat both alive and dead? And I think you told me that that's not even almost about what we're talking about. But I've forgotten because my memory is great. So how does this, is this the same thing?
31:31 Daniel Whiteson? This is the same concept. Yes.
31:32 Kelly Weinersmith? Okay.
31:33 Daniel Whiteson? The Schrodinger's cat experiment says you have a cat in a box, and it's going to be killed based on some quantum process, which is unpredictable, right? It's truly random. And it does this thing where it tries to connect that quantum process to something classical and intuitive, which is a cat. And so, you know, before you open the box, the cat has a probability of being alive and a probability of being dead. And people like to say it's both dead and alive, which I don't think makes any sense. I think it has a probability of being dead and a probability of being alive. And the quantum version of the story is that before you open the box, it has both probabilities and the universe has not yet decided. And the classical view of that is says, no, no, no, it's determined.
32:14 Daniel Whiteson? You just don't know until you open the box. And the question, the deep question is, can we tell the difference? Can we really know if the universe is playing this undetermined, random game, which would be really, really strange? Or is there some way in which the universe decides all this stuff in advance? And it's all predetermined. We just don't know how it does it. It's just some hidden detail that we're missing that tells one particle to go up and one particles go down. And so those are the two questions. Is it actually random and quantum mechanical and undetermined? Or is there some hidden variable, some detail which is controlling this that we just are missing or not understanding?
32:54 Kelly Weinersmith? All right. So how could you possibly tell the difference? What experiments do we need to do?
32:58 Daniel Whiteson? Well, the best thing to do is the most obvious is like, well, just repeat the experiment multiple times, start it exactly the same way, set it up exactly the same way, the balls or the electrons or whatever, and see, do you get different outcomes? Because if you do it the same way, starting with exactly the same initial conditions multiple times, and you always get the same outcome, then you know it's determined. And if you use the same initial conditions and you get different outcomes, then you know that it's not. That sounds great, right? What a clean experiment. Just test it. The problem is, how do you do the same experiment exactly the same way twice, right? Like, you know, you can never step in the same river twice. If you repeat and experiment the next day, the earth is in a different place around the sun, and the temperature is
33:42 Daniel Whiteson? slightly different, and you had a different breakfast, and there's like a zillion things that you could never control for. And the quantum philosophy nerds are like really nerdy about all these loopholes. And so that's just impossible, even at the particle accelerator. Like, we smash protons together millions of times a second, but it's never exactly the same collision. The angles are slightly different, the energies are slightly different. And so that's essentially impossible. So we need something more clever. You can't just run the same experiment twice, which is a bummer, because, man, that would be awesome.
34:12 Kelly Weinersmith? That would be awesome. Okay, but I'm hoping physicists haven't just thrown in the towel. But maybe you all did, because you were like, oh, shoot, we're probably wrong.
34:21 Daniel Whiteson? No, we did not throw in the towel. There was a very clever guy named John Bell, who came up with an experiment that could tell us the difference between these two hypotheses. One, that the universe has somehow figured this out in advance, and we just are missing the information. And two, that know it's actually random and undetermined until you look, that these particles, even when they're separated by great distance, somehow decide together at the same moment which one is up and which one is down. And it sounds like impossible to tell the difference, but he came up with this really clever way. And unfortunately, there's no like smoking gun individual experiment where you could say, I'm looking at the outcome and it proves A versus B, right? This is not like, do unicorns exist? Oh, I found one.
35:06 Daniel Whiteson? Therefore, we know there are unicorns. The results are a subtle statistical correlation across many experiments.
35:15 Kelly Weinersmith? So is it a quantum result? You, you, there's a constant probability that you're wrong?
35:20 Daniel Whiteson? Briefly, you take measurements of these two distant entangled particles, and you look at how often you get the same result. And if there are hidden variables, you can't get the same result more than two thirds of the time. But quantum mechanics allows you to get the same result on these two particles more than two thirds of the time. It breaks that restriction by not determining the result in advance. But it's a correlation, right? It's not like any individual experiment proves it. It's like a pattern among many, many, many runs of the experiment. So it's a little frustratingly indirect, but it's also mathematically very crisp. And I want to try to walk you through it so you can get an intuition for what's going on here. Okay. So how does this Bell's experiment work? And why is two thirds an important threshold?
36:05 Daniel Whiteson? So imagine I have an electron here in California and there's an electron in Virginia. And we've entangled them so we know if one is up, the other one is down. So what are the possibilities? If I measure up, then Virginia is down. If California measures down, Virginia is up. Okay? So we get opposite spins 100% of the time. So far, this is not evidence of anything. This just says our particles are constrained. They're entangled, right? And it's important for people to understand really what this means because a lot of people don't get the simplicity of what entanglement means. The entanglement just removes some possible outcomes. Like without entanglement, I could get up and you could get up. I could get down and you could get down. Entanglement just says, no, those possibilities are zero. So entanglement just removes possibilities and only leaves the ones that satisfy, in
36:50 Daniel Whiteson? this case, like angular momentum. All right. So we know that they have to be opposite. So far, we haven't learned anything. But remember that also, I don't have to measure spin in the same direction as you do. We have three dimensions of space, X, Y, and Z, right? And I could measure spin along like a Z axis and you can measure it along a Y axis that's perpendicular. Or for example, I can measure it in one direction and you could flip your machine upside down. What happens if you flip your machine upside down? Then we expect that we always get the same answer. If I read up, then you're also going to read up. I would have read down on your particle, but your machine is upside down. So I get up, you get up. If I get down, you get down. So in that scenario, we get the same results 100% of the time,
37:33 Daniel Whiteson? right? Where our machines are flipped, but also the particles are entangled, so they have opposite spins.
37:39 Kelly Weinersmith? Yep.
37:40 Daniel Whiteson? Right? You with me still?
37:41 Kelly Weinersmith? Uh huh.
37:41 Daniel Whiteson? Okay. Bell's experiment says, let's get even weirder, folks. Let's pick three axes in advance. So like, I'm going to pick three directions in space, maybe up and then left, and then also some weird angle in between.
37:55 Kelly Weinersmith? Mm hmm.
37:56 Daniel Whiteson? Okay. So we pick that in advance. We have our electrons, one in California and one in Virginia. Now I randomly choose which of those three axes I'm going to measure my electron on. Is it the Z? Is it the Y? Is it the in-between? You're also going to do that. You're going to randomly choose an axis. Okay?
38:16 Kelly Weinersmith? How do I randomly choose an axis if I, if randomness is so hard to, uh, I can't use the random number generator on my computer, you told me. That's chaotic.
38:26 Daniel Whiteson? No, you're, you're being personicky about it, but in a really actually fascinating way that quantum theorists get really nerdy about. And we're going to talk about that later on. People use like lava lamps and cosmic rays to try to be like really truly random to make sure they're not being like weirdly influenced by something because that randomness is absolutely essential for this whole argument. So we're going to come back to that point.
38:46 Kelly Weinersmith? Okay.
38:47 Daniel Whiteson? And it's going to involve like scripts of Gilligan's Island. It's really weird.
38:50 Kelly Weinersmith? That's great. I was hoping that's where this episode would end up.
38:54 Daniel Whiteson? All right. So we each have an electron and we each have three axes and we randomly pick which axis we're going to measure this electron on, right? So imagine that these things actually are determined, that some hidden variable on this electron makes mine be up and yours be down along some axis, right? It's not random. It's not quantum mechanical. Let's imagine that hidden variables are really at work here. Well, then what would happen? Well, it's all determined in advance, right? I have my three axes, I have my particle, you have your particle. But my particle is actually pointing in some direction. Your particle is pointing in some direction. And so it's all determined in advance. And you can actually enumerate all the possibilities, right? And we have three axes. And so one third of the time, we're going to be choosing the same axis, right?
39:39 Daniel Whiteson? Like, if I choose Z, you're going to choose Z. Because we have three axes and we're both choosing randomly. So a third of the time, we choose the same axis, which means that we'll get the opposite results. Like, we'll choose the same axis, I'll get up and you'll get down, right? So at least a third of the time, we get the opposite results.
39:56 Kelly Weinersmith? Mm-hmm.
39:57 Daniel Whiteson? Which means that we get the same result less than two-thirds of the time, right?
40:01 Kelly Weinersmith? Mm-hmm.
40:02 Daniel Whiteson? Okay. So that's what we expect for hidden variables. And that just comes out of having three axes and choosing them randomly.
40:09 Kelly Weinersmith? Mm-hmm.
40:10 Daniel Whiteson? Okay. So what if there aren't hidden variables? What if there's quantum mechanics going on?
40:15 Kelly Weinersmith? Gasp!
40:16 Daniel Whiteson? Okay. So what happens if there's quantum mechanics going on? So if there's no hidden variables, if quantum mechanics is at play, then there's something sneaky going on here, which is that then the Heisenberg uncertainty principle sneaks in the door. Heisenberg says that there's some things you can't know simultaneously about the universe. Like, you can't know the speed and the location of a particle at the same time, right? Well, it also applies to spins of a particle in different directions. So for example, if I measure the spin of a particle on one axis, I can't know it in the other ones. Or if I measure it in some axis, I can't know it on my first one. So there is no, like, true spin direction of these particles in the quantum mechanical view, right?
41:01 Daniel Whiteson? It's not like there is a true spin and we're measuring it along some axis so we get up or down. It's like scrambled in this weird way. And in the quantum mechanical view, you represent the probability of these particles being spin up or spin down using these complex numbers. Comes out of the Schrodinger equation, and it's all determined by these complex amplitudes. And like in many quantum effects, these complex amplitudes can interfere with each other. And so quantum mechanics allows these particles to interfere with each other. It's not like all set up in advance. They dynamically respond to the situation. And quantum mechanics predicts that you should get the same spin around three fourths of the time. Now, remember, the hidden variables prediction says you cannot get the same spin
41:46 Daniel Whiteson? more than two thirds of the time. Absolutely not. Totally impossible. That would break logic. Quantum mechanics says, no, no, no. At these weird angles, then three fourths of the time, you can get the same spin. If you arrange things right, depending on the angles between your axes, you can get the same spin more than two thirds of the time, up to three fourths of the time.
42:06 Kelly Weinersmith? Okay, so I was totally following you, but adding the Heisenberg uncertainty principle feels like cheating because I don't really understand why that works. And it's like, okay, but also now we're playing by a totally different set of rules that you don't understand, and it makes sense. So could we take a quick break and talk about Heisenberg uncertainty principle just for a second?
42:26 Daniel Whiteson? Yeah, sure. So, you know, Heisenberg uncertainty principle is just a way of thinking about the spread of possible outcomes and what's allowed. And the fact that measurements are connected, that you can't measure one thing independently, put that in a box, know it, and then move on to measure something else. It's just a way of thinking about how like the truth isn't totally determined. And so, and that way, it's kind of a shorthand. We can actually do without introducing the Heisenberg uncertainty principle entirely if we could just think about the nature of quantum measurements. And so really, all you need to know is that the quantum mechanical prediction for whether my California particle is spin up or spin down along some axis is probabilistic, right? That's the quantum mechanical nature of it. It predicts some probability of this and some probability
43:10 Daniel Whiteson? of that. And yours predicts the opposite. And that's very simple. But if you rotate your axis, so you're not measuring along the same axis as I am, there's a relationship between those probabilities. But that relationship is different in the quantum version than in the hidden variables version, because we have these amplitudes, because we have these complex numbers that are interfering with each other. Bell realized that as that rotates, the number changes differently for the quantum version than it does for the true everything is determined hidden variables version. And it's because of those complex amplitudes and the way that calculation happens. And it's really fascinating because normally these complex amplitudes aren't things that you can see, but when there's interference, then those results are apparent.
43:54 Daniel Whiteson? It's sort of like in the double slit experiment. You can't see the probabilities, but you can see them interfering with each other. And so that's roughly what's happening here is that the probability of measuring along one axis is interfering with the probability of measuring along a different axis in a way that gives us a different dependence as the angle changes. And so that comes up with a different prediction. And that's why it's not an individual experiment where you're like, I ran it, I got up and down, and therefore quantum mechanics is correct and hidden variables is wrong. It's like, I ran it a thousand times and I got the same direction for both particles 72% of the time, which is impossible in the hidden variables theory. So it's an average over many experiments.
44:35 Kelly Weinersmith? Okay, so at the end of this experiment, we can say that what's happening is definitely random, not chaotic.
44:41 Daniel Whiteson? Yeah.
44:42 Kelly Weinersmith? And so there are no hidden variables.
44:44 Daniel Whiteson? That's right. And it's incredibly powerful and broad result. It's saying it cannot be a hidden variable, right? You don't even have to know what the hidden variable is. You can imagine some like additional dimension of space and these particles have some features in that space and that's what's determining it. No, we don't even have to discover those dimensions. This proves that that cannot be happening. No hidden variable theory satisfies these experiments. It's really incredible. The consequences are huge, but there's a very important caveat, right? We've been talking about hidden variables and Bell's experiment actually only rules out local hidden variables, information that's like connected to the particle, that like a little detail that like the electron has tucked into its pocket that's determining
45:29 Daniel Whiteson? whether it's going to be plus or minus, right? Local hidden variables. And this was actually misunderstood for decades.
45:36 Kelly Weinersmith? And when we get back from the break, we'll find out why the answer was obscured for so long.
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47:52 Speaker 16 Hey, it's Niall Rogers, host of Before the Moment, a Lincoln original series. I'm driving across the country, meeting some of today's most fascinating artists. We're exploring the stories before the moment that changed everything. This week, I'm joined by my friend, John Legend. So you're helping Will.i.am write hooks. What made "Ordinary People" become the one song from those sound checks you knew you had to make your own?
48:20 Speaker 17 I was just writing for the Black Eyed Peas. I wasn't expecting to write something for myself in that session, but I wrote the hook for "Ordinary People," and I recorded a demo, and I'm like, I would rather keep "Ordinary People" for myself. This station in Chicago, WGCI, they start playing it before we're promoting it. The song spoke for itself. It became the defining song for my first album. I knew it was special, but you never know how special it's going to be and how much impact it's going to have in people's lives. And you never believe that you're going to actually change people's lives with a song.
48:49 Speaker 16 Experience Before the Moment, a Lincoln original series on the iHeartRadio app, YouTube, or wherever you get your podcasts.
49:09 Kelly Weinersmith? All right, we're back, and Bell's experiments were misunderstood for decades, and Daniel's going to explain to us why.
49:16 Daniel Whiteson? So this very smart guy, John von Neumann, he's like widely considered one of the smartest dudes in history, and he's the guy who showed that Heisenberg's matrix quantum mechanics was the same thing mathematically as Schrodinger's wave quantum mechanics, even though those two guys hated each other, really like a towering figure. And he did this proof, this conceptual proof before Bell's experiments that showed that quantum mechanics couldn't have any hidden variables at all. But it turns out there was a mistake in it, and people actually argue about like, was it von Neumann's mistake, or did people misinterpret what von Neumann was saying, and he really understood it? They don't like pointing out mistakes in geniuses' work. But for a long time, the lore was that quantum mechanics was inconsistent with any kind of hidden variable.
50:01 Daniel Whiteson? And it was Bell who came up with these experiments that showed, actually, what they do is they show no local hidden variables. His experiments can't disprove a different kind of hidden variables, non-local, right? Like global hidden variables. And as a result, they're like interpretations of quantum mechanics, like Bohmian mechanics, that have these like global guiding functions, this pilot wave that like tells this particle to go positive and that particle to go negative. So they are deterministic, but they require this like weird, non-local coordination between all the particles in the universe in a strange way that's very counterintuitive. But the big picture result for Bell's experiment is not that it shows no hidden variables,
50:43 Daniel Whiteson? but no local hidden variables, which means that quantum mechanics is weirdly non-local, right? Like, what's happening here is my particle is collapsing and your particle is collapsing at the same time. It's instantaneous across time and space. Quantum mechanics is non-local.
51:02 Kelly Weinersmith? Okay, so Bell proved that there was no local hidden variable.
51:07 Daniel Whiteson? Yeah.
51:08 Kelly Weinersmith? But did we ever convince ourselves that there's no Bohmian global guiding function? Or could there still, that's still an open question?
51:17 Daniel Whiteson? That's still an open question. Now, these Bell's experiments can't tell us whether Bohmian mechanics is correct and there are hidden variables, but they're global, or there are no hidden variables at all, right? So people often interpret Bell's experiments too broadly. They say, well, there's no hidden variables. But actually, they just show no local hidden variables. So if your theory has like weird global hidden variables, yeah, that's still cool. And that's what Bohmian mechanics is. And Bell actually was a strong proponent of hidden variables, right? He thought that global hidden variables were the way the universe worked. So, sort of weird because he's like famous for demolishing hidden variables, but he actually believed in them, but he believed in the global version of it. And people have actually done these experiments. These are not just thought experiments.
52:02 Daniel Whiteson? The first ones were done in the 70s. And then they do them in fancier and fancier ways. And they keep the particles further and further apart to test this question of like, is this really happening instantaneously across time and space? And the way they do this is they entangle the particles and they really do separate them in vast macroscopic distances and then make their measurements at the same time. So there's not enough time for light to go from like California to Virginia to inform my California particle, what happened to your Virginia particle? So we know that this really does have to happen at the same time.
52:37 Kelly Weinersmith? Well, wouldn't that have to mean that the information is traveling faster than light?
52:42 Daniel Whiteson? Yeah. And so this was a question from a listener who wrote in and asked something similar. Here's Mohammed asking his question.
52:49 Speaker 18 Hi, Kelly and Daniel. I would like to understand that if information travels at the speed of light, then how do we know that quantum entanglement is instantaneous? How do we know that the particles influence each other faster than the speed of light when the measurement itself is captured the speed of light? How can we measure them precisely at the same time? When the particles have moved far apart after they are entangled, they are subjected to change in gravitational field. And that seems to me like it is enough to throw everything out of whack. So what kind of witchcraft allows us to know GR?
53:24 Daniel Whiteson? All right. And so, yeah, Mohammed is asking, how do we know it's faster than light? And Kelly is asking, doesn't that violate everything I thought I know about physics?
53:31 Kelly Weinersmith? I've been listening.
53:34 Daniel Whiteson? And so to answer Mohammed's question, what they do is they bring these things really far apart and they make the measurement simultaneously as they can. So if they know that they make the measurement within a microsecond, then as long as they're further apart than a light microsecond, further apart than light can go in a microsecond, then they know that the collapse is faster than light. You can't prove it's literally instantaneous, but you can prove that it's faster than light because the particles are separated by more distance than light could go in the intervening time. And so how does that not violate relativity? Well, relativity tells us no information. Can be transmitted from California to Virginia faster than light. But no information is being transmitted. Like if I measure my particle and it goes from undetermined to up,
54:20 Daniel Whiteson? then Kelly's particle goes from undetermined to down, but she doesn't know that. There's no information she's gathered there. She just has her particle. She hasn't measured it yet. When she goes to measure it, she sees, oh, it's down. She doesn't know whether it was collapsed or not. People often write in, they're like, what if Daniel collapses his particle? Then Kelly can see that it's collapsed and that's a way to communicate information faster than light. But Kelly has no way to know whether her particle is collapsed or not. All she can do is measure it and say, oh, I got a minus. She doesn't know if she's collapsing it to get that minus or if it was already collapsed. So yes, the quantum wave function is non-local. It extends from California to Virginia and collapses simultaneously across space,
55:02 Daniel Whiteson? which is really weird, but you can't use it to transmit any information from California to Virginia faster than light. And so it doesn't break special relativity, which feels like a really lawyerly loophole, but it's true.
55:16 Kelly Weinersmith? All right, all right. Let's clear up Kelly's misconception here. So my first thought was, well, the information between those two electrons has already been transmitted when they were entangled. And so no information is being transmitted when one is actually observed because they already were tied, but they don't know if they're up or down yet until they're observed. And so there is, okay, I get it.
55:41 Daniel Whiteson? That's really insightful. Yeah. So what's happening when you're entangling them is you're removing some possibilities, right? You're removing the up, up and the down, down possibilities. You're only leaving the up, down and the down, up. However, we're leaving those possibilities undetermined. And so when I make my measurement, it crosses one more off your list, leaving you with only one possibility. So that is happening across space and time. But you're right, the entanglement itself is local and it was made when the particles were created in these initial states.
56:15 Speaker 19 Hey, Daniel and Kelly. This is Matt. You may remember me from editing audio on your show. I was in the middle of editing this episode when some of this stuff that Daniel was saying started to hurt my brain, much in the way seemingly that it hurt Kelly's brain. And I have a question for you. One thing in particular that I'm having an especially hard time understanding is the observational element of quantum physics. How and why does it matter if the state of a particle is or isn't being observed? Do quantum particles have awareness? Are they shy? What is it about observation that determines or sets
56:58 Speaker 19 a quantum object in place, so to speak? Doesn't this mean that consciousness is somehow related to the state of things? That consciousness somehow dictates or influences reality? And if so, doesn't this indirectly mean that before consciousness evolved in the universe, the universe didn't fully exist? If you could shed some light on this matter, I'd really appreciate it. But I'm fully prepared to be confused about this for the rest of my life. Thanks.
57:31 Daniel Whiteson? All right. Great question, Matt. So first, remember that observation is not passive. It's active. It requires some kind of interaction with the thing you're studying. You want to see a particle, you have to bounce a photon, a probe off of it in order to see where it is. You want to measure the spin of your electron, you have to put it through a magnetic field that acts like a probe and interacts with it. So observation requires interaction. Now, if that interaction yields information, that means that your probe is now entangled with the system. That's because if the way your probe particle behaves afterwards depends on the electron's spin, then your probe is entangled with the quantum system because
58:13 Daniel Whiteson? the spin of the electron determines what the probe does. So now your probe is part of the system. But if, for example, your probe was badly designed, so it doesn't depend on the electron spin, it doesn't extract information, then it's decoupled and it's not entangled. So it's not about consciousness or shyness, it's about interacting in a way that yields information about the state of the system. Now, whether this wave function collapsed or not is another question of philosophy. Copenhagen interpretation says, "Interaction collapses the wave function if one of the objects involved is classical," like if the probe is classical. But it also doesn't define what classical means and why quantum objects, when they
58:56 Daniel Whiteson? come together, somehow become classical. The major alternative, many-world hypothesis, says that interaction entangles you and you become part of the system, so now you only see one outcome. There's no collapse, you're just along one of the branches. But philosophically, the whole thing is kind of a mess. All right, great question, but Kelly, let's go back to your other fun loophole, which is, this experiment requires people to choose axes at random and then measure how often something happens over a bunch of random trials. How do we know that those are random? We're testing randomness, it relies on randomness, is there some circularity there? Are we on firm ground? And there's a really fun, kind of paranoid, theory of quantum mechanics called super-determinism.
59:41 Daniel Whiteson? And it says, "Look, the outcome of these experiments relies on those things being random, but what if they weren't? What if Kelly and Dana were manipulated somehow into choosing axes that give this result?" Because if they're not random, then the result can't be relied on. And, you know, what if it all is actually determined by something that happened a billion years ago and set this series in motion? And so to try to get around this loophole, they've done really hilarious things, like they've made the choice super-duper chaotic, like they randomly sample scripts from television shows, and, you know, like, if the letter is greater than K, then they choose this axis, and if it's less than G, you know, in the third line of page two, this kind of stuff.
1:00:23 Daniel Whiteson? And they combine it with lava lamps and cosmic rays to try to get like as random as possible. But in the end, super-determinism is something you can never really totally knock down, because there's always some crazy paranoid theory you could have, that these things are just being orchestrated by folks in the simulation, or super-intelligent aliens, or something.
1:00:46 Kelly Weinersmith? All right. So, so all of our best efforts at getting random numbers say the same thing, that Bell's experiment works.
1:00:53 Daniel Whiteson? Yeah.
1:00:53 Kelly Weinersmith? Okay.
1:00:54 Daniel Whiteson? Yeah. And so broadly, the consensus in the community is yes, the universe really is random at the microscopic level, really is undetermined. And these extraordinarily subtle, but very clever experiments reveal that that's how the universe works at the lowest level. And it relies not just on the universe being random and the results being undetermined, but having these tests with particles that are distant from each other, yet quantum mechanically having their fates connected to each other.
1:01:22 Kelly Weinersmith? Okay. And so now, nobody should ever be confused again about entangled particles.
1:01:28 Daniel Whiteson? This stuff entangles your brain, for sure.
1:01:30 Kelly Weinersmith? Yeah, it does. Follow up questions, welcome.
1:01:33 Daniel Whiteson? But it's a moment where you should be skeptical, where you should ask, hmm, how do we know that's really true? I hear this all the time. People are telling me quantum mechanics is random. What experiment really proves it? And you should demand an answer. And you should demand an intuitive explanation that satisfies you, because this is something that's true about the whole universe, and the philosophical implications are huge and far reaching. And so before you like, update your priors and change the way you look at the universe, like, make sure it makes sense to you.
1:02:01 Kelly Weinersmith? I think my new favorite conspiracy theory is super determinism.
1:02:08 Daniel Whiteson? Because it includes all the other conspiracy theories.
1:02:10 Kelly Weinersmith? That's right. That's right.
1:02:13 Daniel Whiteson? All right. Well, thanks very much, everyone who wrote in asking for an explanation of quantum entanglement. I hope that helped.
1:02:19 Kelly Weinersmith? It sure helped me. Have a good day, everyone.
1:02:28 Kelly Weinersmith? Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio. We would love to hear from you.
1:02:33 Daniel Whiteson? We really would. We want to know what questions you have about this extraordinary universe.
1:02:39 Kelly Weinersmith? We want to know your thoughts on recent shows, suggestions for future shows. If you contact us, we will get back to you.
1:02:46 Daniel Whiteson? We really mean it. We answer every message. Email us at [email protected] .
1:02:52 Kelly Weinersmith? Or you can find us on social media. We have accounts on X, Instagram, Blue Sky, and on all of those platforms, you can find us at D and K Universe.
1:03:02 Daniel Whiteson? Don't be shy. Write to us.
1:03:05 Speaker 15 Are you looking for support in your weight management journey? Zepbound Terzepatide may be able to help. Zepbound is a prescription medicine used with a reduced calorie diet and increased physical activity to help adults with obesity, or some adults with overweight who also have weight-related medical problems to lose excess body weight and keep the weight off. Zepbound is approved as a 2.5, 5, 7.5, 10, 12.5, or 15-milligram injection. Zepbound contains Terzepatide and should not be used with other Terzepatide-containing products or any GLP-1 receptor agonist medicines. It is not known if Zepbound is safe and effective for use in children. Don't share needles or pens, or reuse needles. Don't take if allergic to it,
1:03:49 Speaker 15 or if you or someone in your family had medullary thyroid cancer, or if you've had multiple endocrine neoplasia syndrome type 2. Tell your doctor if you get a lump or swelling in your neck. Stop Zepbound and call your doctor if you have severe stomach pain or a serious allergic reaction. Severe side effects may include inflamed pancreas or gallbladder problems. Tell your doctor if you experience vision changes before scheduled procedures with anesthesia. If you're nursing, pregnant, plan to be, or taking birth control pills. Taking Zepbound with a sulfonylurea or insulin may cause low blood sugar. Side effects include nausea, diarrhea, and vomiting, which can cause dehydration and worsen kidney problems. Talk to your doctor. Call 1-800-545-5979, or visit zepbound.lily.com.
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1:05:41 Speaker 14 This is an iHeart Podcast. Guaranteed Human.
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