Subtitles section Play video Print subtitles There's this popular program called “Stranger Things” on TV and as a fan and as a physicist I've come up with a theory and just forewarning there's gonna be some spoilers In Stranger Things, one of the characters, Will, gets trapped in this sort of parallel universe called the Upside Down and when he's trapped there his mom is you know really worried about him But she figures out that he's not missing and that actually she can communicate with him when he's in this parallel universe and she does it by Stringing up some Christmas lights on the wall and under each light bulb she writes a letter and so from this parallel universe The kid manages to light a light bulb above a letter and spell out a message to his mom Yeah, basically, and so I was thinking as a physicist How is this even possible? How does one communicate from a whole other universe to our universe in 1983? And so I've come up with this theory—this physics fan theory—and I think that this is possible if this parallel universe called the upside down is quantumly entangled with our universe. I guess we've got to understand quantum entanglement first. First of all you've got to get rid of everything that you know about the classical world so in the classical world this Is a red ball, and it will always be a red ball similarly, this is a blue ball, and this will always be a blue ball, and if I sort of Shuffled them around and hold one in either hand When I say to you you know, which one is the red ball, and which one is the blue ball We know that one of them is definitely red and one of them is definitely blue and so it's only when I open my hand And say okay, that was the blue ball And there was the red ball that we knew all along that this was blue, and this was red but one of them is always blue and one of them is always red. If this was the quantum world and you couldn't tell which one was red or which was blue they would both be red and blue at the same time. So this is like the Schrodinger's cat example—the cat is both dead and alive at the same time. [Brady:] They both purple? They're both purple—yes, they are! So there's some sort of weird linear superposition of red and blue in the quantum world and it's only when we again we open the hand and we see that this one is blue that we know this one is red. But before that, they were both. So if we have two quantumly entangled particles instead in this weird quantum mechanical world these can have sort of any properties so what I was doing there was this color was an analogy for spin, basically or some property of the particle so spin up and spin down and that is a very fundamental property of particles and so if we have these Quantumly entangled particles they don't have any spin yet, they do have spin It's just that you can't describe one without describing the other okay So they're in this weird superposition state where they can be both spin up and spin down But the thing about quantumly entangled particles is that as soon as you measure them and one becomes spin up the other one immediately becomes spin down so whatever one of them does, the other one has to do the exact opposite, and that's what quantum entanglement is. Poor Will trapped in this parallel universe if this entire universe Was quantumly entangled with our universe then anything that Will does in the parallel universe has to be reflected in our universe as well: the particles have to do the exact opposite so say Will could take the light bulb in the parallel universe of the upside down and Put a battery to it and force the electrons in that light bulb to move around a circuit he would have given them momentum in a direction and Therefore the particles in our universe would have to do the exact opposite does that mean they would also have to have momentum But in the opposite direction and therefore also Move around a circuit and therefore light up a light bulb so if he lit up a light bulb in his universe the light bulb Would also light up in our universe Himself Wouldn't that when he moves the battery wouldn't the No this is where this sort of theory is a little bit like we're gonna have to think about this I mean I'm also assuming That you know these light bulbs are in parallel you know they're not in series in their in their circuit They're in parallel. I mean this is 1983. They could be in series I don't know. This is the kind of thing that you have to achieve all the way you go through this theory The electrons in his he'll be able to manipulate electrons in the other exactly through quantum entanglement, that's my theory Would you like to hear how this theory is absolutely rubbish so there are many problems But so as a scientist. I had to think through these problems and go through them the first question I had was easy even possible to make a quantum Leontine board universe okay, so that just seems ridiculous in my head Turned out not so ridiculous So I actually found a paper quantum entanglement in the multiverse and this is you know a theoretical paper but they're actually talking about it as if we could measure whether this has actually happened in our own universe so what they're saying is if Our universe is one of many and the multiverse theory holds that there are many many universes then after the Big Bang Ten to the minus thirty-six seconds after the Big Bang to be precise there was this period of time called inflation where the universe rapidly inflated in the space of sort of from ten to the minus Thirty-six to sort of like ten to the minus thirty-three seconds so a very very short space of time inflated very rapidly and that has like loads of consequences on sort of how the universe is today because any sort of teeny tiny fluctuations And the particles that were created just after the Big Bang were sort of locked in so density Fluctuations anything like that will then spread out over these huge Distances and that meant that then some areas of the universe more dense than the others and that's how you ended up getting galaxies forming their eccentric cetera so they're saying if you have inflation in the multiverse and you're creating sort of child universes from say our parent universe so lots of Multiverses are sort of springing off and you have inflation then the same properties are going to be Imprinted in one universe as in the child universe as well like in identical twins So that's what inflation would do it would imprint both those things And if you had two particles that work in these quantum the entanglement state in the beginning Then they will be quantum entangled in these two separate universes and the really cool thing about this paper is that they suggest that actually? If this was true in our universe. You'd actually be able to test whether that was true because these kind of quantum entanglement Fluctuations, that would be imprinted in inflation you'd still be able to see in what's called the Cosmic Microwave Background which is this? Microwave signal which is a remnant of the bang in the very early stages of the universe? Where light could first escape from the early stage in the universe so I? Think that's really exciting and the fact that my crazy fan Theory could actually you know in our own universe could exist I was like that was that was one point to me That's one point. There is another problem, and it's something called quantum decoherence if you have two quantum entangled particles And you want to send a message between the two of them say you're doing it for like encryption or something and you move One particle say you know 300 miles away and measure One thing to have a certain span of momentum and therefore the other one has to do the exact opposite This is what Einstein was really concerned about you were there for Sending a message faster than the speed of light because as soon as this one is measured this one Automatically changes and so that is sort of this spooky action at a distance and we know that things Can't travel faster than the speed of light people have got around that now by saying well I had to physically move this 300 miles away first to send that message And I couldn't have made that travel faster than the speed of light Therefore the message itself didn't travel faster than the speed of light because if I move that you know Very very close to the speed of light say 99 percent of the speed of light over here, and then I transfer that message transfer a message back Then that has trouble fast in the speed of light But that's not possible so as soon as I measure this one Spin up and this one it's been down that is an irreversible process And the reason for that is you've had to put energy into this system Okay, so you've had to say okay? This one has to be sped up this one has to be spin down And what you've done is you've put energy into the universe this is somehow Interacted with the environment that it's in and with the universe and you've increased the entropy of the universe So for those of you who are paying attention in school that should raise a little red flag the second law of thermodynamics says that you cannot decrease the entropy of the universe so we've increased the entropy by doing that measurement and Measuring to say that yes, this one has been up and this one has been down And so you cannot reverse that process because reversing it you would have to decrease the entropy of the universe to do that so any interaction with your environment breaks quantum entanglement So what does that mean in terms of my crazy fan? Theory as soon as? Will has moved the electrons and set up a circuit in one light bulb He couldn't do it again in that same light bulb so when his mum has strung up the lights With a single letter under every single light he won't be able to use the same letter twice so we have to get very creative with his lettering and in the show he writes the words right here, so he uses e twice and therefore I don't think my theory holds because He wouldn't be able to use eat Weiss Under our understanding of quantum entanglement and quantum decoherence. He always sees an H twice as me Right here. Yeah, okay, okay? I'll do that again So I could influence his thoughts for example How would I influence his thoughts well I'd have to change the biochemistry I was a biochemistry about it's about electrons so somehow my electrons would have to couple They'd have to become strongly quantum mechanically entangled with brady's electrons

B2 universe quantum light bulb bulb entangled spin Stranger Things - Sixty Symbols 23 2 林宜悉 posted on 2020/03/30 More Share Save Report Video vocabulary