I've been wondering about the quantum entanglement for years. This is the best explanation ever. Great script and animation for easier understanding. I appreciate people worked on this great video.
It seems to myself the two entangled say particles are like a cogs one is spinning clockwise the other anticlockwise then take them apart they stay synchronous with each other in all directions when measured However if they become out of sync or asynchronous in all directions they would loose mesh with each other and would break the wave function the synchronization Sorry for the gearbox analogy it was just a random throught floating around
Hahahaha The top two comments I was like, wait. Who the fuck are these people and what language are they speaking and I’m jealous. And then this comment. Thank god for it
As they all say, before the measurement you CAN'T know what the configuration of the particle is. In other words they cannot prove that this phenomenon is real. Attempts at proving that the phenomenon is real have only been carried out by varying a measurement of an already set configuration, so there is no proof at all that this phenomenon is real.
That was the most original (and unusual!) way of breaking down QE I've ever witnessed. Dr Lincoln's creativity is simply as infinite as the Unobservable Universe!
I would really have liked an explanation on why the wave function and hidden variables hypothesis gives different prediction of probability at say 20 degrees angle?
Think about it in terms of rotating both detectors instead of just one. If you rotate detector B 20 degrees you get X% difference, if you rotate it -20 degrees (i.e. 20 degrees in the opposite direction) you get the same X% difference. So if you assume hidden variables, then rotating detector B 20 degrees and detector A -20 degrees should yield no more than 2X% difference (since the particles are just following their hidden variable programming and neither has any idea what's happening at the other detector). If you picture both detectors rotating simultaneously in opposite directions, the percentage difference should be a linear progression as the difference from detector B is always equal to the difference from detector A. But quantum mechanics predicts *greater* than the 2X% difference (based on the overall angle of separation between both detectors), which is impossible unless the particle at detector A "knows" the angle of detector B and vice versa. Someone smarter can feel free to correct me, but I think that's the gist of it :)
@@RoboBoddicker could we not measure one particle in a certain position and hold for a specific amount of time and then measure the other in all directions and use the angles to send information? (This is assuming that the angle as stated in the video is a real angle and not an analogy to explain stuff easier)
@@SkyWave32 Once you measure the particle you change it's state (the wave function collapses). So after you measure the spin against the chosen alignment you cannot inquire any further what the particle's spin was before the measurement. Think of it trying to put a piece through a shaped hole. Either the piece fits through the hole and becomes the shape of the hole or it doesn't and becomes the exact opposite. Either way it can no longer be changed. edit: fixed my analogy a bit just to make it super clear
It’s the same as his explanation for 90 degrees in the video. The point is that it doesn’t matter how you measure the second particle, it will have the opposite spin from the measurement of the first particle.
Thank you. This is the very best explanation that I've heard as to how Bell's Theorem detects that entanglement is not due to hidden variables. Great explanation!!!
A physicist friend of mine said this to me about the subject, and I'll never forget it: "It's only 'spooky' if you think about the behavior from a human's temporal point-of-view. Because for the photon, the events of entanglement, separation, and measurement effect all occur at the exact same time."
It is true that from light's "point of view", there is no passage of time. Quantum comms are still 'spooky' though, in that all macroscopic phenomena are limited by the speed of light - to anything with mass, time does exist, and light speed is a limit to transfer of information - yet quantum information travels infinitely fast. So how is it travelling? It's not by light - because as Don explains, that's been tested for and ruled out - it travels 'instantaneously'. However, the whole thing has never seemed too bizarre to me. The universe started from a single point of space-time, so it doesn't seem too implausible (to me) to suppose that stuff going on 'under the hood' has remained 'connected' in some fashion. And as Don says, it doesn't break relativity because we can't use this mechanism to break the speed of light limitation on movement of mass or information. And then too, I always found John Cramer's "Transactional Interpretation" of Quantum Mechanics to be more plausible and pleasing than the unreasonably-popular "Copenhagen Interpretation" (which has hung around well beyond its sell-by date mainly because of that bloody silly alive-and-dead cat being sexy to layman types). In addition to that, TI is mathematically more aesthetic - by interpreting 'negative time' solutions as being "information travelling back in time", rather than ignoring it as "obviously nonsense" (as Copenhagen and other interpretations do). Kids get told off for ignoring 'the other' root, and imaginary numbers seem to be 'used' in the universe, so it seems dodgy to not try to interpret them. Those signals ('advanced waves'), travelling back in time can form atemporal 'handshake' communications - which neatly explain a lot of 'spooky' stuff like the double slit experiment, that bloody cat, and perhaps spooky action at a distance, all in a more (to some, anyway) philosophically pleasing way, i.e., without requiring infinitely branching universes (Many Worlds), or the existence of intelligent (?) observers to actually make anything happen or the universe exist. See Wikipedia < en.wikipedia.org/wiki/Transactional_interpretation > or the 1995 book "Schrodinger's Kittens (and the Search for Reality)" by John Gribbin.
What blew my mind about quantum entanglement is that entangled particles have the same wave functions not just in space but also in time. Thanks for posting a video about it Prof. Lincoln.
@ It is not interesting to regard the history of physics with the aim of deciding who was the best, a champion is not enough for physics. E.g. Schrödinger's articles published after EPR are an essential contribution to our understanding of entanglement. What would have been QM without von Neumann (hence Hilbert), Dirac, Feymann, just to name a few and not mentioning too many? From our perspective what is relevant is all the contributions of those people, and we are lucky to have *all* of them.
I knew if I kept revisiting this subject I would eventually I’d gain a greater understanding. Thank you for being the first I’ve seen to break down vital details necessary for the average person (interested in this) to understand more meaningfully. You have been so helpful!
I'd like to thank Jada PS for bringing me here. Now I learnt something new and now I understand what she was talking about...2 particles in a single wave pattern. Brilliant!
6:15 - 8:08 This is probably the most important educational physics video on TH-cam, by virtue of the concept it explains, and especially the apparent paradox it reconciles.
Quantum entanglement is one of the most intriguing and enigmatic phenomena in modern physics, often referred to as "spooky action at a distance," a term famously coined by Albert Einstein. This phenomenon occurs when two or more particles become correlated in such a way that the state of one particle instantaneously affects the state of another, no matter how far apart they are. This defies the conventional understanding of physics, where information transmission is thought to be limited by the speed of light, creating a significant challenge to classical notions of locality and causality. At the heart of quantum entanglement is the principle that once particles are entangled, their properties are no longer independent of each other. For instance, if two electrons are entangled in a certain way, measuring the spin of one electron immediately determines the spin of the other, regardless of the distance separating them. This connection seems to happen instantaneously, which Einstein found troubling, as it appeared to imply that information could travel faster than the speed of light, violating the principles of special relativity. Experiments conducted over the years, including those by physicist John Bell and subsequent tests of Bell's theorem, have shown that the predictions of quantum mechanics hold true and that entangled particles do exhibit correlations that cannot be explained by any local hidden variable theory. These results have solidified the understanding that quantum entanglement is a real and measurable phenomenon, although its implications continue to challenge our understanding of reality and the nature of space and time. Entanglement has practical applications in emerging technologies such as quantum computing and quantum cryptography. Quantum computers leverage the entangled state of qubits to perform complex calculations exponentially faster than classical computers. Quantum cryptography, meanwhile, uses entanglement to enable secure communication, as any attempt to eavesdrop on entangled particles would disturb their state and be detectable. Despite its fascinating potential and experimental validation, quantum entanglement still raises philosophical and theoretical questions. For instance, what does it mean for the concept of locality and causality? Is there a deeper underlying principle connecting entangled particles, or is the connection purely a fundamental aspect of quantum mechanics? These questions fuel ongoing debates about the nature of reality and the role of consciousness in the quantum world. In conclusion, quantum entanglement represents a profound departure from classical physics, challenging our most basic assumptions about the universe. While it is a cornerstone of quantum mechanics and has promising applications in technology, it also serves as a reminder of the limits of human understanding when it comes to the fundamental nature of reality. The "spooky action" that Einstein found so troubling continues to intrigue scientists and philosophers alike, pushing the boundaries of what we know and inviting us to reconsider the interconnected fabric of the universe.
This is the first time I have properly understood the concept, although had seen many videos on the topic earlier. Thanks a lot for the lucid explanation! Really mind blowing.
Intriguing video. I took high school physics about 40 yrs ago, so I don't even know if this is even an intelligent question, but here goes: How is the spin of a particle observed or measured? How do we know that particles only spin up, down, left or right if we can never observe such a small thing?
The triangle wave is linear. But the wave function is sinusoidal. Linear would be two separate clocks where you reading them at the same time. The graph is linear because you're dividing. Say 12 divided by 1 oclock.
The idea is (as far as my layman mind can grasp it): Hidden variables tells you that the two spins are in opposite directions, and the first one is "closer" to spin up than the second, but you can't know the actual, original spins. Quantum Mechanics says that when you measure the first spin to be up, the other one BECOMES spin down - without any probability weirdness. So you don't need to integrate over all possibilities - there is only one. And thus the result is different.
Lack of data points so they join the points with straight lines (isnt this what plagues all physics?); at a more subtle level this is fundamentally what is wrong with Quantum Physics we only have data at the points of measurement he he
The mathematical functions for hidden variables and quantum mechanics are continuous, so there's no need to join points or "extend the function". The real difference is that the QM function is probabilistic, and as such yields a gaussian distribution. The HV function is fully determined by initial conditions, so there is no probability game into play and the percent of what's measured (amount of measurement agreement) increases linearly to 100%, then decreases the same way. Given that QM yields a line that fits the experimental results much more closely, the scientists conclude that QM is better for describing the phenomenon and making predictions about it.
I see it as a problem with how they are imagining the hidden variables. If you have a random vector being detected it has a probability as well so Hidden variables can create sine waves.
If you assume the hidden variable is not time-varying, you get the anticipated straight line. But if you allow time-varying hidden variables, and admit that time-keeping varies from one location to another, then the time-varying hidden variables drift in and out of sync (e.g there is a non-vanishing "beat frequency'), and the straight line model gives way to the one we actually find in experimental measurements.
I was actually pleasantly surprised to NOT learn something new from one of your videos (for once)! This makes me feel like I have a decent grasp of this topic. I don't think this is going to hold for the quantum teleportation video! :) Could you also do one about quantum encryption? I feel like that would be both fascinating and enlightening. Thanks for the great videos!!!
When we measure the spin of any particle we are actually interacting it with field which means there are other particle involved ( meausuring device), thus measurement is another entanglement.
This was fascinating, and very well explained for the most part. I really like that you just didn't explain it, but you also explained the experiment. Although it's still hard to wrap my mind around it, it's definitely better than not knowing how this was measured at all. (I'd still like to know more about how those two lines colored lines on the graph differ, though!)
Yes I understand why hidden variables gives the graph that it does but not 100% sure why quantum physics would predict the other graph. That would be a nice video for the future
For that same reason, I actually did not like this particular video. TBF, I didn't find a video yet which explains the experimentation and meaning behind it properly, just the inferences of the experiments, analogies and what it means for the phenomenon of Quantum Entanglement.
@@_sayan_roy_ Yeah, I get you. It's a complex topic and there were some good explanations, but the graph itself is not explained, and I'd like to see how those differing lines are arrived at (which was not done here...or apparently, anywhere else that is easily assessible and made for regular people).
@@Rationalific Hey, I got one Veritasium video which made me understand quite a bit, of course, after pondering a lot on that by myself. The video is 7 years old and you can search by quantum entanglement or spooky action at a distance. There is a video of Sabine as well but not as good as Veritasium's, on the details we want.
I feel like you didn't truly go into depth about what the hidden variable theory would predict, and what the results truly show us, for example if measured at the 45 degree angle. Another video showing a proof of Bell's inequality would help, I feel.
I would definitely love that. I never understood why hidden variable theory is supposed to be wrong and just stating that's what it'd predict without any explanation whatsoever makes the whole thing unconvincing for me
The best video I remember is from Minute Physics, but Veritasium also did one. I don't think Space Time or Science Asyluym did one, but I am not 100% sure. At least not until you measure me :P
I would guess. The hidden variable theory is linear like dividing times on a clock. A moving clock hand does not turn sinusoidal compared to the angle or time. It turns linear. But the wave function is sinusoidal compared to the angle.
My understanding of quantum entanglement hinges on knowing why the idea of hidden variables doesn't work. This helped that understanding, I see how the predictions are different, where one is a triangle wave and the other is a sine wave. Still don't know why the predictions are different.
That's in the graph at 12:50 -- I don't understand why you would even request that. Or do you mean measuring the first particle at 45º? That's trivial, we know the result: 225º for the entangled couple.
The video doesn't cover why the hidden variable must result in that particular probability line. At a surface level, it feels like there should be forms of hidden variable(s) that would deliver a curve similar to quantum mechanics.
You can't use a random function for describing any hidden variables. In this particular case, you have a result (value of measurement for the second particle) fully depending on the measurement on the first particle (because at the beginning there are only 1 blue and 1 red balls, so if one is red/spin up, the other must be blue/spin down). So the equation needs to be y=-x or more in general y=ax+b, which is a straight line equation
See Sabine H. I think what's going on is the hidden variable is what you measure. "What a quantum particle does depends on what measurement will take place. The 2022 Nobel was likely for proving Bell Wrong. See Measurement Independe. See Sabine H.
@@TheNasaDude This is important: "What a quantum particle does depends on what measurement will take place." - Sabine H. It's likey Bell was proved wrong because he assume measurement independence. What if you understand what Sabine's saying what i am saying might make sense.
I see that the quantum entanglement “red bell curve” is different in shape than the hidden variables “blue pyramid”; however, I don’t understand WHY they’re different. I think that extra bit of information would’ve been great to help us compare the predictions made by both interpretations, but perhaps it would’ve taken too long to go into the math that determines those probability predictions?
That's letf out because the only way to explain it is with math i think. This guy explains that part in his video th-cam.com/video/-WSWz1H3mJg/w-d-xo.html
It feels errant to say "therefore information can travel faster than light". Why are we assuming anything is being transmitted? What if these two point-like particles are intersections of some other higher-dimensional brane?
Do you think theorists coming up with concept of "brane" gave it such name just to troll? ;) Anyway, to be specific, it's "quantum information" and "traveling faster than light" is just a shortcut, a stopgap (like dark energy and dark matter) - a plaque saying "fix me". Don't know much about super- theories but wouldn't brane fall into hidden variables category?
Well we know that it's not physical spin, because we're talking about point particles with r=0. It's a specific property that we just call spin to make visualisation easier. That said, we know little more than that about spin, besides that it can be -1, -1/2, 0 , 1/2 or 1 (also values chosen for ease of grasp). Same goes for charge. We've figured out how it works, but what it is exactly? Scientist still cannot answer that question. What scientists do is make up theories that fit current data, and are testable for new variables or refinement of known variables. It's the only way forward on the path of knowledge.
Yes. Spin is an abstract form of angular momentum. And it is one of the bedrock principles that angular momentum is conserved. This is why if you measure the spin of one particle to be up, the other had to be down, assuming you specify the same direction in each measurement. What Bell showed is that the correlations observed cannot be reproduced by pre-assigning all possible outcomes to the particles when they first separate. This, combined with the purely randomness of each measurement in isolation (meaning they appear random at each end, but when the observers compare notes, spooky correlations emerge), rules out hidden variables. Here's a video that goes into more detail about that, giving examples of how hidden variables fail to explain the data: th-cam.com/video/ZuvK-od647c/w-d-xo.html
Listen, I'm still in high school and hadn't had physics in about 3 years. The last time I had it I almost got a D on my report card. For some reason I gained an interest in quantum physics. I would like for you know Dr. Don that your videos are amazing! I watched a lot of them and learned so so much! You explain it so well and eventhough English is not my native tounge I can understand and follow them very well. Thank you so much for these great videos. They make to facinating world of quantum phyics so much more accessable! Thank you.
That's what I tell people as well. People seem to misunderstand Einstein's comment, thinking that he was somehow scared. In reality, he called it "spukhafte Fernwirkung" in clear reference to what you mention. In German, Fernwirkung is legitimate physics terminology for the forces of Newtonian mechanics, i.e., forces acting instantaneously over finite distances. Wirkung in this usage comes from the old times, when even Newton was calling forces "actio." Given the context, I would assume that Einstein really meant it as a derisive description by putting a quantum phenomenon in the same category as a discredited idea from classical physics. The "spooky" is just added to emphasize the joke, to make it clear that he didn't really think that's what's going on.
@@noeckel I still think that Einstein is wrong by saying that light is constant, light is proved by quantum entanglement not to be, whene they say that 2 atoms are in 2 places at the same time, they see such effect because light goes IN then goes OUT way to fast that in a matter of a very, very, very small fraction of a second it comes and goes to where it needs to go so they only see the atom whene it stops in one side then whene it stops in the other side cause the atom acts as a marble in a band that goes in one direction then stops to change to the other side. Atoms entangled are like a band whene the up side goes left the bottom side goes to the right.
@@noeckel light dobles each time that is why gravity in a free fall the speed doubles each second. The serie PHI goes kind about the same but not realy, you now 1pluss 1= 2, 2 and 1= 3, 3 and 2= 5 and so on that in a matter of few times passes light speed anlist the numbers.
@@Motorfirez gravity is the results of space-time bending and the variations of the bending (gravitational waves) propagate at the speed of light. Relativity sets the "speed of light" as the speed limit of causality, this is why quantum entanglement is out of rule.
Isn't it easier to assume we lack knowledge about (opposite) rotation, than to assume things travel faster than light? Couldn't said particles be set off in specific opposing rotations that we lack insight of?
This helps a lot. I’ve taken several science for dummies courses on physics including his Theory of Everything with the Teaching Co. (No, I don’t even know anyone working for them.) However, I’ve struggled to understand this even after five or six courses for science dummies. This is simple and fascinating. By the way, it’s hard to blame Einstein for being bewildered by this and calling it spooky action. And he had a very human overreaction to it by not liking quantum mechanics or theory. (Dr. Lincoln gave a reassuring explanation that would probably reassure Einstein (and the rest of us) that he could appreciate his relativity and quantum mechanics.) Thanks for a great video!
Interesting how Einstein made such significant contributions to quantum mechanics with his papers on Brownian Motion and the Photoelectric Effect, yet he is always remembered for his "God does not play dice" remark.
.... it doesn't need to travel ftl, you can't compare the effect until after both measurements are made and you have brought the results together, we just get confused about it since we think of ourselves as being seperate from the wave function, when we are all part of it, the perception of it being probabilistic is just observation bias
I would compare it to sending 1 glove from a pair to 2 people far apart from each other. If person 1 opens theirs and it's the left glove, the other person immediately knows the other one is the right glove. No data has been transmitted to either person
@@dcquence That analogy is misleading, as which side is being sent which glove is theoretically knowable at the point where the gloves are packaged aka, hidden variables. Both of the possibilities happen, we know this from a variety of external tests where, as opposed to examining one particle, we make them interact with each other and see their interference, it's just, we have a huge bias against applying the math to ourselves when we interact with one of them, and get into the same superposition as it is in, at which point, we should not be surprised at all to find that interactions with someone that interacted with th other particle are consistent
Yah but how does the second person KNOW the first person has a left glove. How is that information being transmitted faster than light Further, that analogy would require that person one could suddenly make his left glove a right glove, and that persons twos glove would immediately become a left glove And they wouldn’t, plus the analogy breaks down in usefulness because gloves can’t switch left/right orientation
Quantum entanglement is a sketchy thing. Finaly this video connects it with worship of chaos gods. Should i now prepare to see The Pope as follower of Khorne or Slanesh?
For me, this was your best video. Quantum mechanics, prooves that the world is material and dialectic. This means that always is an existence of cause which is going to give e result but it is impossible to predict the exact probability of this result till it happens.
Brilliant explanation of a very complex topic. Keeping the focus on the wave function and angular momentum helps to get a grip on a really mind bending part of modern physics. And topped off by a wonderful plot of predictions by two competing explanations. This video is of value not simply for the specific topic of entanglement, but also how scholars deal with highly complex and non intuitive phenomena.
I have two unique balls, one blue and the other red. I place both inside sealed containers, so that you can't tell which is which until you open them. My brother chooses one of the containers at random, and flies off light-years away into a spaceship. I sometime decide to open my container and I find the red ball. I instantly know that my brother has the blue ball. No information traveled faster than light. EDIT: Omg, you used the same example! Now, that is probability in action. EDIT2: Oh well, I stand corrected. I was using the hidden variables hypothesis without realizing it, and it turns out to be false.
That's the hidden variables hypotheses. Quantum entanglement is this: You have two unique balls, both balls can have any color you wish. You chose one to be red and the other blue. You put them in boxes... you send your brother light years away... and before you open your box you start changing the color of your ball. So now, how would you instantly know the color of the ball that your brother has? Exactly... You can't. Your brother's ball can have any color... So anyway you start changing the color of your ball and your brother opens his box and observes the color of his ball changin too! And not randomly but according to the color that your ball has... So when your ball is red his ball is blue, when your ball is green his balls is yellow, when your ball is pink his ball is orange etc... In this case you can't instantly know anything, so you might have to conclude that somehow the other ball knew how to change its colors to correctly match the "opposite" color of your ball... So information about the state of your ball was traveling faster than light to reach the one your brother has!
Actually, no; what you (and Don) described is simply 'maximum correlation' - which, in QM, is represented by some vector in a _maximally_ entangled subspace. "HV" refers to the possibility of using classical probability distributions to describe the QM results - different thing altogether
hi.. Sorry but i have to disagree with you on that you can not use this to transfer information. I will attempt to explain how to use this to transfer information. Lets assume technology is advanced enough so we can read the states of these entangled particles relatively quickly, although the speed of measurement does not invalidate this theory. If we had 1 particle on a mars rover, and 1 particle here on earth (lets say). Both particles are being measured at a default speed of say 100Hz. Lets assume Up is a 1 and down is a 0. If here on earth i want to transmit a 0 followed by a 1, the transmitter(earth particle) would ramp the measurement speed to say 1khz, the receiver stays at 100hz, the transmitter would continue to measure at this higher speed until it got a result that is down, the transmitter would then not measure again for 1 clock cycle of the receiver, the transmitter would repeat again of measuring at the high speed throwing away all the measurement results if it was up then hold again when a down is measured. If this is repeated about 10 times the receiver would see a block of downs. If the same is then repeated for up (i.e the transmitter throws away all the measured downs and hold on up), you have then transmitted at a relatively slow baud rate the bits 0 followed by a 1. The only limit that determines the baud rate of data flow is the rate at which one can perform a measurement on the particles, but nevertheless whatever the baud rate, that data was transmitted faster than light.. I hope you get a chance to read this and comment.. Many thx...
I dropped physics last school year as we had a few topics in class I didn't totally understand and now I am grievously sad because this video made me want to have physic lessons at school again.
what he says makes no sense. Be ok. You are smarter then him, that is why you do not understand what he says. Means you correctly get that it makes no sense. He is fermilab, he is the main stream.
hey fother mucker how are you doing? I just thought you could be happy to by one hour slot via skype to heal the wounds you carry.. 60usd/hour special price for you.
Love your video. It's very instructive. When I think about the why of quantum entanglement, and how the spin measurement of one particle determines the spin of the other, at seemingly faster than light speed - there's a lot of "why" left on the table to explain. One idea that I think deserves more attention is quantized spacetime. If there is such a thing as quantized spacetime, then the particles of such spacetime would have the properties of superposition, and entanglement. In this scenario, two entangled electrons could exist in the confines of entangled spacetime. What appears to us as two electrons, separated by a vast distance, is actually local as far as the electrons are concerned. The entangled spacetime in which they reside, makes it appear to us that the electrons are far apart - when they are actually right next to each other. In this hypothesis, there's no violation of special relativity. And most importantly, no violation of causality. The entangled spacetime implies an extra dimension that we cannot see directly - but this dimension manifests in such a way that two electrons, from our viewpoint, can be far apart - and yet appear to be communicating faster than light allows. To take physics to the next level - it's my opinion that the key problem to solve is the "why" of quantum entanglement. Quantized spacetime may offer an answer. Quantized spacetime may also help with ideas related to quantum gravity - which is another reason to further develop this field of study. The one thing we do know, that we cannot allow in our theories, is a violation of causality - because if that happens, Physics becomes a land of anything goes. Please carry on.
The explanation lies in a single word: relativity. If you don't understand why that's enough, then you are simply admitting that you weren't paying enough attention in undergrad physics.
@@lepidoptera9337 But the "why" behavior of quantum entanglement does not lie in a single word. However, I don't think special relativity is being violated by QE. That's why it's such a puzzle. How to reconcile the apparent contradiction? Something else is going on that perhaps involves additional dimensions arising from quantized spacetime, or perhaps the so-called many-worlds hypothesis explains QE's apparent faster-than-light collapse of the wave function. Or maybe, as some have speculated, the wild idea the QE creates the spacetime in which it operates. In any case, causality must be preserved - which implies that special relativity must be obeyed. And here we are in 2024, and we still don't have a solid explanation for the apparent violation of SR by QE. Instead, we have a lot of head scratching - a few ideas on the table - and a mystery with no definitive answer.
Well done. I'll bet the script for that video took a very long time to develop. If you don't have one, a video on how experimental physicists measure this would be great.
I want to get there in my studies some day. It is great to find a video like this in a situation where my instructors only killed my interest in physics.
That was a very clear and easy to understand explanation of quantum entanglement. There is some kind of link between entangled particles. When that is understood, other mysteries will be revealed.
Hi Dr. Lincoln, Great video's you make ! I have a question about idea's that are around as to what this entanglement actually means. In another youtube video about the origin of time, I heard that perhaps time may have been a spacial dimension before it became time as we know/experience it. Would it be possible for quantum particles to (still) be experiencing that pre-time dimension, and not experience time as we (macroscopics) do ? Thanks for the great work ! Physics is everything ! Dirk
Is the wave function a mathematical description or is it a "thing" that causes change itself, i.e causal? I cannot see how it is causal, which is implied by some of the "explanations" talked about. Non-locality remains as the most weird thing in the ultimate nature of existence, still.
Would you please make video about Light interference pattern? As far as I know interference pattern is different when we are observing and when we are not.
Great video as usual! Now I don't have much knowledge about quantum mechanics but I have two questions, firstly has there ever been an experiment that proves that information is transmitted faster than the speed of light ? and if so how was it conducted? Secondly, if hypothetically, there was a way to take a bunch of entangled particles and store one of each pair in a way in which they couldn't interact with anything else, separate them by a lightyear or whatever and have two people measure their spin in only the vertical direction. The two people agree to measure their particle, say every second but the second person measures it 0.5 seconds after the first person. Couldn't the first person's measurement ( UP or DOWN), be read as ( DOWN or UP) by the second person and if they agree that UP is 1 and DOWN is 0 or vice verca, wouldn't that enable them to communicate in Binary instantaneously over great distances? There must be some information I'm missing out on but if someone could explain why it isn't possible that would be cool :)
I have a simple question. If you are constantly looking at 2 entangled particles with known opposite spin direction, and you changed the direction of one particle's spin, would the other also change even though you did nothing to that particle?
You can't do that experiment. As soon as you measure a particle's spin, the particle is absorbed. All you can observe are the statistics of millions of particles.
@@ragnaarminnesota6703It is true that you can change spin without measuring it. Everything I wrote is true. You probably just don't understand QM. That's understandable.
@@david203 Reread everything. You said you can't do that experiment. Sabine was arguing against spooky action when she said what I am repeating. Given this video, are you arguing against spooky action? The PBS Space time guy said Einstein was proven wrong by spooky action. Was he?
Could it be that nothing is transmitted, but that the wave function collapse collapses backwards in time? This would allow the entangled information to be shared at the moment of entanglement, correct?
Super presentation as always... Would like to get the exact reference to Einstein referring to "quantum entanglement" as "spooky action at a distance"...
Why is the prediction for hidden variables at 12:40 linear, but the one for quantum mechanics more like a sine? Intuitively I would have expected a sine for both.
I've been wondering about the quantum entanglement for years. This is the best explanation ever. Great script and animation for easier understanding. I appreciate people worked on this great video.
It seems to myself the two entangled say particles are like a cogs one is spinning clockwise the other anticlockwise then take them apart they stay synchronous with each other in all directions when measured However if they become out of sync or asynchronous in all directions they would loose mesh with each other and would break the wave function the synchronization Sorry for the gearbox analogy it was just a random throught floating around
Dr. Don, It literally makes my day when I see a new video of yours has been uploaded. Thank you VERY much for all that you do!
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That was really helpful, can you just explain that part again about everything?
Me too. It would help if my mind wasn't blown by the video. But heck, if Einstein found it weird...
Lol. I would appreciate it if he focused more on each sentence he said.
Is that you Fry?
Hahahaha
The top two comments I was like, wait. Who the fuck are these people and what language are they speaking and I’m jealous. And then this comment. Thank god for it
Rewind the video
I love this guy. I understood maybe 20% of the information he talked about, but I 100% know he’s the man .
As they all say, before the measurement you CAN'T know what the configuration of the particle is. In other words they cannot prove that this phenomenon is real. Attempts at proving that the phenomenon is real have only been carried out by varying a measurement of an already set configuration, so there is no proof at all that this phenomenon is real.
I'm just a cabinetmaker and writer of novels, but I love that you explain physics in a way I can understand. (mostly lol)
Multi-skilled!
That was the most original (and unusual!) way of breaking down QE I've ever witnessed.
Dr Lincoln's creativity is simply as infinite as the Unobservable Universe!
I would really have liked an explanation on why the wave function and hidden variables hypothesis gives different prediction of probability at say 20 degrees angle?
Veritasium: "Quantum Entanglement & Spooky Action at a Distance" th-cam.com/video/ZuvK-od647c/w-d-xo.html
minutephysics: "Bell's Theorem: The Quantum Venn Diagram Paradox" th-cam.com/video/zcqZHYo7ONs/w-d-xo.html
Think about it in terms of rotating both detectors instead of just one. If you rotate detector B 20 degrees you get X% difference, if you rotate it -20 degrees (i.e. 20 degrees in the opposite direction) you get the same X% difference. So if you assume hidden variables, then rotating detector B 20 degrees and detector A -20 degrees should yield no more than 2X% difference (since the particles are just following their hidden variable programming and neither has any idea what's happening at the other detector).
If you picture both detectors rotating simultaneously in opposite directions, the percentage difference should be a linear progression as the difference from detector B is always equal to the difference from detector A. But quantum mechanics predicts *greater* than the 2X% difference (based on the overall angle of separation between both detectors), which is impossible unless the particle at detector A "knows" the angle of detector B and vice versa.
Someone smarter can feel free to correct me, but I think that's the gist of it :)
@@RoboBoddicker could we not measure one particle in a certain position and hold for a specific amount of time and then measure the other in all directions and use the angles to send information? (This is assuming that the angle as stated in the video is a real angle and not an analogy to explain stuff easier)
@@SkyWave32 Once you measure the particle you change it's state (the wave function collapses). So after you measure the spin against the chosen alignment you cannot inquire any further what the particle's spin was before the measurement. Think of it trying to put a piece through a shaped hole. Either the piece fits through the hole and becomes the shape of the hole or it doesn't and becomes the exact opposite. Either way it can no longer be changed.
edit: fixed my analogy a bit just to make it super clear
It’s the same as his explanation for 90 degrees in the video. The point is that it doesn’t matter how you measure the second particle, it will have the opposite spin from the measurement of the first particle.
Thank you. This is the very best explanation that I've heard as to how Bell's Theorem detects that entanglement is not due to hidden variables. Great explanation!!!
I watched many videos on these. This is the most explanatory one. Thank you Dr. Lincoln and FermiLab members who made this possible.
Yeah same here.
A physicist friend of mine said this to me about the subject, and I'll never forget it:
"It's only 'spooky' if you think about the behavior from a human's temporal point-of-view. Because for the photon, the events of entanglement, separation, and measurement effect all occur at the exact same time."
It is true that from light's "point of view", there is no passage of time. Quantum comms are still 'spooky' though, in that all macroscopic phenomena are limited by the speed of light - to anything with mass, time does exist, and light speed is a limit to transfer of information - yet quantum information travels infinitely fast. So how is it travelling? It's not by light - because as Don explains, that's been tested for and ruled out - it travels 'instantaneously'.
However, the whole thing has never seemed too bizarre to me. The universe started from a single point of space-time, so it doesn't seem too implausible (to me) to suppose that stuff going on 'under the hood' has remained 'connected' in some fashion. And as Don says, it doesn't break relativity because we can't use this mechanism to break the speed of light limitation on movement of mass or information.
And then too, I always found John Cramer's "Transactional Interpretation" of Quantum Mechanics to be more plausible and pleasing than the unreasonably-popular "Copenhagen Interpretation" (which has hung around well beyond its sell-by date mainly because of that bloody silly alive-and-dead cat being sexy to layman types). In addition to that, TI is mathematically more aesthetic - by interpreting 'negative time' solutions as being "information travelling back in time", rather than ignoring it as "obviously nonsense" (as Copenhagen and other interpretations do). Kids get told off for ignoring 'the other' root, and imaginary numbers seem to be 'used' in the universe, so it seems dodgy to not try to interpret them.
Those signals ('advanced waves'), travelling back in time can form atemporal 'handshake' communications - which neatly explain a lot of 'spooky' stuff like the double slit experiment, that bloody cat, and perhaps spooky action at a distance, all in a more (to some, anyway) philosophically pleasing way, i.e., without requiring infinitely branching universes (Many Worlds), or the existence of intelligent (?) observers to actually make anything happen or the universe exist.
See Wikipedia < en.wikipedia.org/wiki/Transactional_interpretation > or the 1995 book "Schrodinger's Kittens (and the Search for Reality)" by John Gribbin.
as a skeptic, I wonder if you even have "physicist friend"
If you watched the video that is called hidden variables and has already been accounted for and disproven so your 'physicist friend' is wrong
It's made up by mathematicians.
@@jonz23m That's nothing. The entire universe is a figment of my imagination, and no one can prove me wrong, so it must be true! 😁
What blew my mind about quantum entanglement is that entangled particles have the same wave functions not just in space but also in time. Thanks for posting a video about it Prof. Lincoln.
Drop a pebble in a complex (real+imaginary) pond at low signal levels and square-law quantizing detectors, and un-blow your mind.
@ It is not interesting to regard the history of physics with the aim of deciding who was the best, a champion is not enough for physics. E.g. Schrödinger's articles published after EPR are an essential contribution to our understanding of entanglement. What would have been QM without von Neumann (hence Hilbert), Dirac, Feymann, just to name a few and not mentioning too many?
From our perspective what is relevant is all the contributions of those people, and we are lucky to have *all* of them.
There are no sine wave functions in this explanation.
There is no space and time, it's just spacetime.
I knew if I kept revisiting this subject I would eventually I’d gain a greater understanding. Thank you for being the first I’ve seen to break down vital details necessary for the average person (interested in this) to understand more meaningfully. You have been so helpful!
Thank you Dr. Don, you are an exceptional person and scientist.
I'm grateful for the thoughtful and clear explanation .
I'd like to thank Jada PS for bringing me here. Now I learnt something new and now I understand what she was talking about...2 particles in a single wave pattern. Brilliant!
LMAOOO
That's freaky action at a distance, not spooky (unless you are Will of course).
6:15 - 8:08 This is probably the most important educational physics video on TH-cam, by virtue of the concept it explains, and especially the apparent paradox it reconciles.
Quantum entanglement is one of the most intriguing and enigmatic phenomena in modern physics, often referred to as "spooky action at a distance," a term famously coined by Albert Einstein. This phenomenon occurs when two or more particles become correlated in such a way that the state of one particle instantaneously affects the state of another, no matter how far apart they are. This defies the conventional understanding of physics, where information transmission is thought to be limited by the speed of light, creating a significant challenge to classical notions of locality and causality.
At the heart of quantum entanglement is the principle that once particles are entangled, their properties are no longer independent of each other. For instance, if two electrons are entangled in a certain way, measuring the spin of one electron immediately determines the spin of the other, regardless of the distance separating them. This connection seems to happen instantaneously, which Einstein found troubling, as it appeared to imply that information could travel faster than the speed of light, violating the principles of special relativity.
Experiments conducted over the years, including those by physicist John Bell and subsequent tests of Bell's theorem, have shown that the predictions of quantum mechanics hold true and that entangled particles do exhibit correlations that cannot be explained by any local hidden variable theory. These results have solidified the understanding that quantum entanglement is a real and measurable phenomenon, although its implications continue to challenge our understanding of reality and the nature of space and time.
Entanglement has practical applications in emerging technologies such as quantum computing and quantum cryptography. Quantum computers leverage the entangled state of qubits to perform complex calculations exponentially faster than classical computers. Quantum cryptography, meanwhile, uses entanglement to enable secure communication, as any attempt to eavesdrop on entangled particles would disturb their state and be detectable.
Despite its fascinating potential and experimental validation, quantum entanglement still raises philosophical and theoretical questions. For instance, what does it mean for the concept of locality and causality? Is there a deeper underlying principle connecting entangled particles, or is the connection purely a fundamental aspect of quantum mechanics? These questions fuel ongoing debates about the nature of reality and the role of consciousness in the quantum world.
In conclusion, quantum entanglement represents a profound departure from classical physics, challenging our most basic assumptions about the universe. While it is a cornerstone of quantum mechanics and has promising applications in technology, it also serves as a reminder of the limits of human understanding when it comes to the fundamental nature of reality. The "spooky action" that Einstein found so troubling continues to intrigue scientists and philosophers alike, pushing the boundaries of what we know and inviting us to reconsider the interconnected fabric of the universe.
This is the clearest and most understandable explanation of the topic that I've encountered. Thank you.
This is such an underrated channel.
"No matter where you go, there you are." - Buckaroo Banzai
Corollary: No matter where you are, there you go.
Hmm
@Mr. H impossible, you are always moving.
This is the first time I have properly understood the concept, although had seen many videos on the topic earlier. Thanks a lot for the lucid explanation! Really mind blowing.
Intriguing video. I took high school physics about 40 yrs ago, so I don't even know if this is even an intelligent question, but here goes: How is the spin of a particle observed or measured? How do we know that particles only spin up, down, left or right if we can never observe such a small thing?
You explained everything except the most important part, which is why the hidden variables and quantum mechanical predictions are different.
are you talking about the pilot wave interpretation?
The triangle wave is linear. But the wave function is sinusoidal. Linear would be two separate clocks where you reading them at the same time. The graph is linear because you're dividing. Say 12 divided by 1 oclock.
The idea is (as far as my layman mind can grasp it):
Hidden variables tells you that the two spins are in opposite directions, and the first one is "closer" to spin up than the second, but you can't know the actual, original spins.
Quantum Mechanics says that when you measure the first spin to be up, the other one BECOMES spin down - without any probability weirdness. So you don't need to integrate over all possibilities - there is only one. And thus the result is different.
+1
There's a video that explains it !! its from veritasium ,and he explians the experiment, and how the probabilities work
I'm curious to see how/why hidden variables yields straight lines, whereas quantum mechanics yields a sine wave.
Lack of data points so they join the points with straight lines (isnt this what plagues all physics?); at a more subtle level this is fundamentally what is wrong with Quantum Physics we only have data at the points of measurement he he
I thought I missed the explanation at first for the straight line prediction, but I researched and didn't find it
The mathematical functions for hidden variables and quantum mechanics are continuous, so there's no need to join points or "extend the function".
The real difference is that the QM function is probabilistic, and as such yields a gaussian distribution. The HV function is fully determined by initial conditions, so there is no probability game into play and the percent of what's measured (amount of measurement agreement) increases linearly to 100%, then decreases the same way.
Given that QM yields a line that fits the experimental results much more closely, the scientists conclude that QM is better for describing the phenomenon and making predictions about it.
I see it as a problem with how they are imagining the hidden variables. If you have a random vector being detected it has a probability as well so Hidden variables can create sine waves.
If you assume the hidden variable is not time-varying, you get the anticipated straight line. But if you allow time-varying hidden variables, and admit that time-keeping varies from one location to another, then the time-varying hidden variables drift in and out of sync (e.g there is a non-vanishing "beat frequency'), and the straight line model gives way to the one we actually find in experimental measurements.
I was actually pleasantly surprised to NOT learn something new from one of your videos (for once)! This makes me feel like I have a decent grasp of this topic. I don't think this is going to hold for the quantum teleportation video! :) Could you also do one about quantum encryption? I feel like that would be both fascinating and enlightening. Thanks for the great videos!!!
This is the clearest presentation on this subject that I have ever seen.
Best video on quantum entanglement I've seen so far. Well explained for dummies as well as deep facts for physicists.
Thank you Dr. Don.
When we measure the spin of any particle we are actually interacting it with field which means there are other particle involved ( meausuring device), thus measurement is another entanglement.
Oh boy
Yes, the observer also obeys the shrodinger equation and becomes entangled with the object being measured
This was fascinating, and very well explained for the most part. I really like that you just didn't explain it, but you also explained the experiment. Although it's still hard to wrap my mind around it, it's definitely better than not knowing how this was measured at all. (I'd still like to know more about how those two lines colored lines on the graph differ, though!)
Yes I understand why hidden variables gives the graph that it does but not 100% sure why quantum physics would predict the other graph. That would be a nice video for the future
For that same reason, I actually did not like this particular video. TBF, I didn't find a video yet which explains the experimentation and meaning behind it properly, just the inferences of the experiments, analogies and what it means for the phenomenon of Quantum Entanglement.
@@_sayan_roy_ Yeah, I get you. It's a complex topic and there were some good explanations, but the graph itself is not explained, and I'd like to see how those differing lines are arrived at (which was not done here...or apparently, anywhere else that is easily assessible and made for regular people).
@@Rationalific Hey, I got one Veritasium video which made me understand quite a bit, of course, after pondering a lot on that by myself. The video is 7 years old and you can search by quantum entanglement or spooky action at a distance. There is a video of Sabine as well but not as good as Veritasium's, on the details we want.
@@_sayan_roy_ Thanks! I'll check it out.
One of best general explanations of quantum entanglement I've seen on the web.
Love the shirt... Fermilab is great; This is my 2nd time viewing all of the uploads. Thank you for making Physics fun.
I feel like you didn't truly go into depth about what the hidden variable theory would predict, and what the results truly show us, for example if measured at the 45 degree angle.
Another video showing a proof of Bell's inequality would help, I feel.
I would definitely love that. I never understood why hidden variable theory is supposed to be wrong and just stating that's what it'd predict without any explanation whatsoever makes the whole thing unconvincing for me
The best video I remember is from Minute Physics, but Veritasium also did one.
I don't think Space Time or Science Asyluym did one, but I am not 100% sure.
At least not until you measure me :P
I would guess. The hidden variable theory is linear like dividing times on a clock. A moving clock hand does not turn sinusoidal compared to the angle or time. It turns linear. But the wave function is sinusoidal compared to the angle.
My understanding of quantum entanglement hinges on knowing why the idea of hidden variables doesn't work. This helped that understanding, I see how the predictions are different, where one is a triangle wave and the other is a sine wave. Still don't know why the predictions are different.
That's in the graph at 12:50 -- I don't understand why you would even request that. Or do you mean measuring the first particle at 45º? That's trivial, we know the result: 225º for the entangled couple.
The video doesn't cover why the hidden variable must result in that particular probability line. At a surface level, it feels like there should be forms of hidden variable(s) that would deliver a curve similar to quantum mechanics.
You can't use a random function for describing any hidden variables. In this particular case, you have a result (value of measurement for the second particle) fully depending on the measurement on the first particle (because at the beginning there are only 1 blue and 1 red balls, so if one is red/spin up, the other must be blue/spin down). So the equation needs to be y=-x or more in general y=ax+b, which is a straight line equation
Yes, I thought very similar.
@@TheNasaDude You just explained what I disagree with.
See Sabine H. I think what's going on is the hidden variable is what you measure. "What a quantum particle does depends on what measurement will take place. The 2022 Nobel was likely for proving Bell Wrong. See Measurement Independe. See Sabine H.
@@TheNasaDude This is important: "What a quantum particle does depends on what measurement will take place." - Sabine H. It's likey Bell was proved wrong because he assume measurement independence. What if you understand what Sabine's saying what i am saying might make sense.
I see that the quantum entanglement “red bell curve” is different in shape than the hidden variables “blue pyramid”; however, I don’t understand WHY they’re different. I think that extra bit of information would’ve been great to help us compare the predictions made by both interpretations, but perhaps it would’ve taken too long to go into the math that determines those probability predictions?
That's letf out because the only way to explain it is with math i think.
This guy explains that part in his video
th-cam.com/video/-WSWz1H3mJg/w-d-xo.html
quantum entanglement can be mesured as data and hidden variables are posibilities, so it's a perfect "line", data vs predictions
Watching it today 05.07.2020. This is the best explantion one can deliver. Thank you Fermilab and Linclon.
Thank you for giving today's date. I wondered when I was.
This is one of the best plain language explanations of Bell's inequality ever done. Thanks!
It feels errant to say "therefore information can travel faster than light". Why are we assuming anything is being transmitted? What if these two point-like particles are intersections of some other higher-dimensional brane?
Why are we even assuming that space time is anything but a perceptual construct?
Why are you assuming that reality exists and it's not just a flux of ideas projected in your mind by God?
Do you think theorists coming up with concept of "brane" gave it such name just to troll? ;)
Anyway, to be specific, it's "quantum information" and "traveling faster than light" is just a shortcut, a stopgap (like dark energy and dark matter) - a plaque saying "fix me". Don't know much about super- theories but wouldn't brane fall into hidden variables category?
Why are we even assuming pineapple pizza could taste good.
@@charlesjohnson9879 Because it's not the matrix.
I need to buy the whole collection of his t-shirts!
B...but have we understood this property we're calling "spin" well enough to try to reason so much more about it?
Well we know that it's not physical spin, because we're talking about point particles with r=0. It's a specific property that we just call spin to make visualisation easier. That said, we know little more than that about spin, besides that it can be -1, -1/2, 0 , 1/2 or 1 (also values chosen for ease of grasp). Same goes for charge. We've figured out how it works, but what it is exactly? Scientist still cannot answer that question. What scientists do is make up theories that fit current data, and are testable for new variables or refinement of known variables. It's the only way forward on the path of knowledge.
Yes. Spin is an abstract form of angular momentum. And it is one of the bedrock principles that angular momentum is conserved. This is why if you measure the spin of one particle to be up, the other had to be down, assuming you specify the same direction in each measurement. What Bell showed is that the correlations observed cannot be reproduced by pre-assigning all possible outcomes to the particles when they first separate. This, combined with the purely randomness of each measurement in isolation (meaning they appear random at each end, but when the observers compare notes, spooky correlations emerge), rules out hidden variables.
Here's a video that goes into more detail about that, giving examples of how hidden variables fail to explain the data:
th-cam.com/video/ZuvK-od647c/w-d-xo.html
Real good comprehensive explanatipn on quantum entanglement. Thanks to prof. Don.
❤
Thank you!! One of the best no bs explanations of entanglement and Bell's Theorem!
Listen, I'm still in high school and hadn't had physics in about 3 years. The last time I had it I almost got a D on my report card. For some reason I gained an interest in quantum physics.
I would like for you know Dr. Don that your videos are amazing! I watched a lot of them and learned so so much! You explain it so well and eventhough English is not my native tounge I can understand and follow them very well. Thank you so much for these great videos. They make to facinating world of quantum phyics so much more accessable! Thank you.
Newton's gravitational force was also "spooky action at a distance"
That's what I tell people as well. People seem to misunderstand Einstein's comment, thinking that he was somehow scared. In reality, he called it "spukhafte Fernwirkung" in clear reference to what you mention. In German, Fernwirkung is legitimate physics terminology for the forces of Newtonian mechanics, i.e., forces acting instantaneously over finite distances. Wirkung in this usage comes from the old times, when even Newton was calling forces "actio." Given the context, I would assume that Einstein really meant it as a derisive description by putting a quantum phenomenon in the same category as a discredited idea from classical physics. The "spooky" is just added to emphasize the joke, to make it clear that he didn't really think that's what's going on.
@@noeckel I still think that Einstein is wrong by saying that light is constant, light is proved by quantum entanglement not to be, whene they say that 2 atoms are in 2 places at the same time, they see such effect because light goes IN then goes OUT way to fast that in a matter of a very, very, very small fraction of a second it comes and goes to where it needs to go so they only see the atom whene it stops in one side then whene it stops in the other side cause the atom acts as a marble in a band that goes in one direction then stops to change to the other side. Atoms entangled are like a band whene the up side goes left the bottom side goes to the right.
@@noeckel light dobles each time that is why gravity in a free fall the speed doubles each second. The serie PHI goes kind about the same but not realy, you now 1pluss 1= 2, 2 and 1= 3, 3 and 2= 5 and so on that in a matter of few times passes light speed anlist the numbers.
@@noeckel vielen dank for your comment, I like the original version of "spooky action at a distant", to foreigners it really sounds "scary" :-)
@@Motorfirez gravity is the results of space-time bending and the variations of the bending (gravitational waves) propagate at the speed of light. Relativity sets the "speed of light" as the speed limit of causality, this is why quantum entanglement is out of rule.
Isn't it easier to assume we lack knowledge about (opposite) rotation, than to assume things travel faster than light? Couldn't said particles be set off in specific opposing rotations that we lack insight of?
No, that would be hidden variables
@@ekotar1 Instant communication good, hidden variables bad?
That is what is called determinism.
@@ekotar1 Hidden variables have not been ruled out. See Sabine H.
@@paulmichaelfreedman8334 Super Determinism is the right path.
This helps a lot. I’ve taken several science for dummies courses on physics including his Theory of Everything with the Teaching Co. (No, I don’t even know anyone working for them.) However, I’ve struggled to understand this even after five or six courses for science dummies. This is simple and fascinating. By the way, it’s hard to blame Einstein for being bewildered by this and calling it spooky action. And he had a very human overreaction to it by not liking quantum mechanics or theory. (Dr. Lincoln gave a reassuring explanation that would probably reassure Einstein (and the rest of us) that he could appreciate his relativity and quantum mechanics.) Thanks for a great video!
Interesting how Einstein made such significant contributions to quantum mechanics with his papers on Brownian Motion and the Photoelectric Effect, yet he is always remembered for his "God does not play dice" remark.
Yo is this about jada and aug?
Yup, she's been getting some Spooky Action distant from Will's eyes.
Could you talk about delayed choice quantum eraser experiment?
Answers with Joe made a great and funny video about it
"This video is long".
No, Dr. Lincoln, none of your videos will be ever long enough.
came here to say this
Thanks Don, you're the only one that explained this in a way that I was finally able to understand. You're the man!
Best video on quantum entanglement.... Really helpful ❤
.... it doesn't need to travel ftl, you can't compare the effect until after both measurements are made and you have brought the results together, we just get confused about it since we think of ourselves as being seperate from the wave function, when we are all part of it, the perception of it being probabilistic is just observation bias
I would compare it to sending 1 glove from a pair to 2 people far apart from each other. If person 1 opens theirs and it's the left glove, the other person immediately knows the other one is the right glove. No data has been transmitted to either person
@@dcquence That analogy is misleading, as which side is being sent which glove is theoretically knowable at the point where the gloves are packaged aka, hidden variables. Both of the possibilities happen, we know this from a variety of external tests where, as opposed to examining one particle, we make them interact with each other and see their interference, it's just, we have a huge bias against applying the math to ourselves when we interact with one of them, and get into the same superposition as it is in, at which point, we should not be surprised at all to find that interactions with someone that interacted with th other particle are consistent
Yah but how does the second person KNOW the first person has a left glove. How is that information being transmitted faster than light
Further, that analogy would require that person one could suddenly make his left glove a right glove, and that persons twos glove would immediately become a left glove
And they wouldn’t, plus the analogy breaks down in usefulness because gloves can’t switch left/right orientation
It sounds an awful lot like a plain old "IF THEN" statement in some sort of natural rendering engine.
Would make sense since the coding language processes faster than the simulation
OK Dr. Don, gonna ask it anyway: What about Shrödinger's dog?
Excellent presentation!!!!
Best explanation available. Wow!
Chaos worship going on in your thumbnail.
Seems Dr Don is a Tzeentch worshipper. Heresy
Quantum entanglement is a sketchy thing. Finaly this video connects it with worship of chaos gods. Should i now prepare to see The Pope as follower of Khorne or Slanesh?
Let's try different model for hidden variable theory.
8:13 could it be that the 2 particles are merely 2 lower-dimensional projections of the same higher-dimensional meta-particle?
Interesting
Why, yes, it is entirely possible. 😮
excellent explanation!!! It took me to watch several videos until I found this one and now I can understand it much better.
For me, this was your best video. Quantum mechanics, prooves that the world is material and dialectic. This means that always is an existence of cause which is going to give e result but it is impossible to predict the exact probability of this result till it happens.
Posted 49 seconds ago, yet already 30 views. Yay, science!
So, quantum entanglement is not local because "data".
Most unsatisfactory ending since GoT...
Lol. Seriously, I just laughed out loud at work. Thanks a lot. 😆
@@nickgivent3157 you're welcome.
That would mean that nothing is traveling from one particle to the other but that it was already there such as an outreaching entangled quantum field!
Brilliant explanation of a very complex topic. Keeping the focus on the wave function and angular momentum helps to get a grip on a really mind bending part of modern physics. And topped off by a wonderful plot of predictions by two competing explanations. This video is of value not simply for the specific topic of entanglement, but also how scholars deal with highly complex and non intuitive phenomena.
Thank you for the clarity of video.
OK THEN. NOW HOW TO WE CHANGE THIS TO MAKE WIFI FASTER??????
I have two unique balls, one blue and the other red. I place both inside sealed containers, so that you can't tell which is which until you open them. My brother chooses one of the containers at random, and flies off light-years away into a spaceship. I sometime decide to open my container and I find the red ball. I instantly know that my brother has the blue ball. No information traveled faster than light.
EDIT: Omg, you used the same example! Now, that is probability in action.
EDIT2: Oh well, I stand corrected. I was using the hidden variables hypothesis without realizing it, and it turns out to be false.
That's the hidden variables hypotheses.
Quantum entanglement is this:
You have two unique balls, both balls can have any color you wish. You chose one to be red and the other blue. You put them in boxes... you send your brother light years away... and before you open your box you start changing the color of your ball. So now, how would you instantly know the color of the ball that your brother has?
Exactly... You can't.
Your brother's ball can have any color...
So anyway you start changing the color of your ball and your brother opens his box and observes the color of his ball changin too! And not randomly but according to the color that your ball has... So when your ball is red his ball is blue, when your ball is green his balls is yellow, when your ball is pink his ball is orange etc...
In this case you can't instantly know anything, so you might have to conclude that somehow the other ball knew how to change its colors to correctly match the "opposite" color of your ball... So information about the state of your ball was traveling faster than light to reach the one your brother has!
I was thinking same thing
@@-_Nuke_- Very nice analogy, thanks!
Actually, no; what you (and Don) described is simply 'maximum correlation' - which, in QM, is represented by some vector in a _maximally_ entangled subspace. "HV" refers to the possibility of using classical probability distributions to describe the QM results - different thing altogether
hi.. Sorry but i have to disagree with you on that you can not use this to transfer information. I will attempt to explain how to use this to transfer information. Lets assume technology is advanced enough so we can read the states of these entangled particles relatively quickly, although the speed of measurement does not invalidate this theory. If we had 1 particle on a mars rover, and 1 particle here on earth (lets say). Both particles are being measured at a default speed of say 100Hz. Lets assume Up is a 1 and down is a 0. If here on earth i want to transmit a 0 followed by a 1, the transmitter(earth particle) would ramp the measurement speed to say 1khz, the receiver stays at 100hz, the transmitter would continue to measure at this higher speed until it got a result that is down, the transmitter would then not measure again for 1 clock cycle of the receiver, the transmitter would repeat again of measuring at the high speed throwing away all the measurement results if it was up then hold again when a down is measured. If this is repeated about 10 times the receiver would see a block of downs. If the same is then repeated for up (i.e the transmitter throws away all the measured downs and hold on up), you have then transmitted at a relatively slow baud rate the bits 0 followed by a 1. The only limit that determines the baud rate of data flow is the rate at which one can perform a measurement on the particles, but nevertheless whatever the baud rate, that data was transmitted faster than light.. I hope you get a chance to read this and comment.. Many thx...
Troll.....😂
This man's explanation is the best i've seen. Thank you so much!
I dropped physics last school year as we had a few topics in class I didn't totally understand and now I am grievously sad because this video made me want to have physic lessons at school again.
I wish I was half as smart as Don Lincoln. Then I would be at least 10 times smarter than I am now.
what he says makes no sense. Be ok. You are smarter then him, that is why you do not understand what he says. Means you correctly get that it makes no sense. He is fermilab, he is the main stream.
Move to Trump country and raise the average IQ in both places.
Don't listen to science deniers like lukas. Even at 1/20th as smart as Don, you're already 100 times smarter than the science deniers around here.
@@EnglishMike mike tell me, what is the smallest particle that is influenced by gravity?
hey fother mucker how are you doing? I just thought you could be happy to by one hour slot via skype to heal the wounds you carry.. 60usd/hour special price for you.
Quantum entanglement blew my mind at one time .then I started believing in simulated universe theories and everything started making sense.
Well shit.... That does make alot of sense.
The final conclusion drawn from all this, all you need is love.
Love your video. It's very instructive. When I think about the why of quantum entanglement, and how the spin measurement of one particle determines the spin of the other, at seemingly faster than light speed - there's a lot of "why" left on the table to explain. One idea that I think deserves more attention is quantized spacetime. If there is such a thing as quantized spacetime, then the particles of such spacetime would have the properties of superposition, and entanglement. In this scenario, two entangled electrons could exist in the confines of entangled spacetime. What appears to us as two electrons, separated by a vast distance, is actually local as far as the electrons are concerned. The entangled spacetime in which they reside, makes it appear to us that the electrons are far apart - when they are actually right next to each other. In this hypothesis, there's no violation of special relativity. And most importantly, no violation of causality. The entangled spacetime implies an extra dimension that we cannot see directly - but this dimension manifests in such a way that two electrons, from our viewpoint, can be far apart - and yet appear to be communicating faster than light allows. To take physics to the next level - it's my opinion that the key problem to solve is the "why" of quantum entanglement. Quantized spacetime may offer an answer. Quantized spacetime may also help with ideas related to quantum gravity - which is another reason to further develop this field of study. The one thing we do know, that we cannot allow in our theories, is a violation of causality - because if that happens, Physics becomes a land of anything goes. Please carry on.
The explanation lies in a single word: relativity. If you don't understand why that's enough, then you are simply admitting that you weren't paying enough attention in undergrad physics.
@@lepidoptera9337 But the "why" behavior of quantum entanglement does not lie in a single word. However, I don't think special relativity is being violated by QE. That's why it's such a puzzle. How to reconcile the apparent contradiction? Something else is going on that perhaps involves additional dimensions arising from quantized spacetime, or perhaps the so-called many-worlds hypothesis explains QE's apparent faster-than-light collapse of the wave function. Or maybe, as some have speculated, the wild idea the QE creates the spacetime in which it operates. In any case, causality must be preserved - which implies that special relativity must be obeyed. And here we are in 2024, and we still don't have a solid explanation for the apparent violation of SR by QE. Instead, we have a lot of head scratching - a few ideas on the table - and a mystery with no definitive answer.
Well done. I'll bet the script for that video took a very long time to develop. If you don't have one, a video on how experimental physicists measure this would be great.
I just like to avoid any Imperial entanglement..
That'll cost you extra.
Chaos symbol detected! Purge the heretic!
I want to get there in my studies some day. It is great to find a video like this in a situation where my instructors only killed my interest in physics.
I like the way you simplified your explanation making it easier for more people to understand easily. :D
The very first time I learned about Quantum Entenglement, my mind just exploded!
Certainly helps me visualize quantum entanglement. Well done.
I appreciate your clear explanations.
4:37 yes 🙌 those descriptions of entanglement really made sense!
That was a very clear and easy to understand explanation of quantum entanglement. There is some kind of link between entangled particles. When that is understood, other mysteries will be revealed.
Best explanation so far thank you!!!
Great video. Thanks.
Hi Dr. Lincoln,
Great video's you make !
I have a question about idea's that are around as to what this entanglement actually means. In another youtube video about the origin of time, I heard that perhaps time may have been a spacial dimension before it became time as we know/experience it. Would it be possible for quantum particles to (still) be experiencing that pre-time dimension, and not experience time as we (macroscopics) do ?
Thanks for the great work ! Physics is everything !
Dirk
I enjoy this channel so much!
Is the wave function a mathematical description or is it a "thing" that causes change itself, i.e causal? I cannot see how it is causal, which is implied by some of the "explanations" talked about. Non-locality remains as the most weird thing in the ultimate nature of existence, still.
amazing, well presented
Would you please make video about Light interference pattern?
As far as I know interference pattern is different when we are observing and when we are not.
Damn, equally weird phenomenon...
Hexanitrobenzene yes
Your the MAN, by a long shot. Thank you Dr. Don Lincoln.
That super clear part really helped.
Great video as usual! Now I don't have much knowledge about quantum mechanics but I have two questions, firstly has there ever been an experiment that proves that information is transmitted faster than the speed of light ? and if so how was it conducted?
Secondly, if hypothetically, there was a way to take a bunch of entangled particles and store one of each pair in a way in which they couldn't interact with anything else, separate them by a lightyear or whatever and have two people measure their spin in only the vertical direction. The two people agree to measure their particle, say every second but the second person measures it 0.5 seconds after the first person. Couldn't the first person's measurement ( UP or DOWN), be read as ( DOWN or UP) by the second person and if they agree that UP is 1 and DOWN is 0 or vice verca, wouldn't that enable them to communicate in Binary instantaneously over great distances? There must be some information I'm missing out on but if someone could explain why it isn't possible that would be cool :)
See Sabine H. There is no FTL comminication. C is the speed of like. What does the C stand for?
I have a simple question. If you are constantly looking at 2 entangled particles with known opposite spin direction, and you changed the direction of one particle's spin, would the other also change even though you did nothing to that particle?
You can't do that experiment. As soon as you measure a particle's spin, the particle is absorbed. All you can observe are the statistics of millions of particles.
@@david203 Wrong. See Sabine H. You can change the spin w/o measuring it. They've done it.
You can change the spin of one of them w/o measuring it. It doesn't do anything to other particle. See Sabine H.
@@ragnaarminnesota6703It is true that you can change spin without measuring it. Everything I wrote is true. You probably just don't understand QM. That's understandable.
@@david203 Reread everything. You said you can't do that experiment. Sabine was arguing against spooky action when she said what I am repeating. Given this video, are you arguing against spooky action? The PBS Space time guy said Einstein was proven wrong by spooky action. Was he?
Could it be that nothing is transmitted, but that the wave function collapse collapses backwards in time? This would allow the entangled information to be shared at the moment of entanglement, correct?
You just discovered the key to time travel!
Super presentation as always... Would like to get the exact reference to Einstein referring to "quantum entanglement" as "spooky action at a distance"...
Why is the prediction for hidden variables at 12:40 linear, but the one for quantum mechanics more like a sine? Intuitively I would have expected a sine for both.
I have the same question, have you figured the answer?
Great explanation 👌 👍
THANK YOU PROFESSOR LINCOLN...!!!