At 9:14 no coherent explanation is given as to why you are producing rabbits for Bob in Alice's 2 pound column. Sure, there's a bit of word salad thrown into the world as if it was a necessity that this be the case, but given the information provided up to that point in the video, nothing compels rabbits in Alice's 2 pound column. Note that I am not claiming that the conclusion is false. I am saying that the logic of the analogy is incoherent. It's perfectly possible to reach a true conclusion from invalid reasoning, but it doesn't help anyone else understand why the conclusion is true! I will provide the required logic to reach the (as it happens, true) conclusion at the end of this comment. The explanation provided was this combination of sentences: 1) "If alice has produced a rabbit with one pound, then the only way we can get a dog is if they both put in 2 pounds. 2) So alice has already put in 1 pound. 3) So bob's box has to produce a rabbit in both of those cases". Statement 1 is contains a non sequitur and is incoherent. If alice has put in one pound, then alice cannot have put in two pounds. There is no "if - then" relationship between the first and second part of the sentence because they describe two completely different cases. You can't create an "if-then" relationship between a case where Alice has put in 1 pound and a case where alice has put in two pounds. The second part of the sentence (1) is false. It is not true that the only way we can get a dog is if they both put in two pounds. We can also get at least one dog if alice puts in 2 pounds and bob puts in 1 pound, and two dogs result. This still satisfies all three rules. Statement (2) is just restating the premise, ie, we are looking at the scenario where alice has put in 1 pound. No problem here, but be careful with use of the word "so....". When making a logical argument, "so..." implies "what I am about to state follows from that which I have just stated", ie, it's often used as a synonym for "therefore". But statement 2 doesn't follow logically from statement 1, therefore use of the word "so..." is confusing. Statement (3) is unclear about which two cases are implied by "both". There are two axes here, the bob axis and the alice axis. If "both" means "both when bob puts in 1 pound, and when bob puts in 2 pounds", then the statement is correct. If alice has put in one pound, then in both of those cases bob must produce a rabbit. But in the graphic, you filled in both of those cases, AS WELL AS both cases where alice puts in 2 pounds. This is "both boths", as it were, and is not justified by the rules. These are the reasons why your explanation is considered unhelpful. Nobody can follow the logic because the logic isn't valid. The resolution to the invalidity is to bring in rule 4, which is the "NB" in italics in the rule slide, but which you do not actually state. That rule *seems* to mean that one box must always produce the same output for a given input. IE, it cannot be the case that bob's box can produce a rabbit on a 1 pound input on some occasions, and can also produce a dog on a 1 pound input.on other occasions. If that is the case then we cannot produce two dogs with the combination (alice 2, bob 1) as I previously suggested, because we have established that the combination (alice 1, bob 1) must produce (rabbit, rabbit) from the combination of rules 1 and 3, so (bob 1) -> rabbit, so we cannot also have (bob 1) -> dog. But this critical part of the logic is *never stated* during your explanation.
My understanding of how we get to 9:35 is in the following steps. Using the notation 1A for 1 pound in A and RA for rabbit in A, etc. Rule 1A -> RA yields the table (RA & ?) ? (RA & ?) ? Rule 1A&1B -> (RA & RB) or (DA & DB) yields (RA & RB) ? (RA & ?) ? Rule 1A&2B -> (RA & RB) or (DA & DB) yields (RA & RB) ? (RA & RB) ? Now, classical mechanics yields (RA & RB) (? & RB) (RA & RB) (? & RB) The not explicit point is that we are testing classical mechanics against the rules! Classical independent boxes imply that if we get RA then the whole column is RA, and if we get RB then the whole row is RB, likewise for D's. The reason being that what happens in A is not affected, i.e. column invariant, from what happens in B and vice versa, i.e. B is row invariant. That we are dealing with classical mechanics is mentioned later. This really got me lost the first time I watched the video, I thought at that point we were just applying the rules just stated. Incidentally, we can fill the table in 4 different ways that completely satisfy the rules IF we do not make any other assumption, but none of those solutions satisfy CM or QM. Ergo, the rules do not replicate QM, at least as I would intend the word "replicate".
Yes, no explanation. I think though in the 2nd column it could have come out a dog or a rabbit, but they've chosen just to put a rabbit as the choice. In the left hand column, the results have to be rabbits though, that bit was explained.
Thank you so much, I didn’t realise the NB was important and just couldn’t make any sense out of his reasonning. This makes it all much clearer, good job.
allmhuran i think it's because of the 3rd rule: you're only allowed to get a Rabbit-Dog pair from the 2p+2p case, so when A used 1p (and got a Rabbit), B will need to also get rabbits. Regardless of which coin B used, they have to get a Rabbit. So for B, the outcome is always a Rabbit, and that is actually independent of A's coin, so it will also happen when A will use her 2p coin. But i agree tbere was no explanation provided in the video, i had to pause there and think about what and why is going on...
@@philipball4720 But is not the concept of the two "entangled" particles being the same object also merely an analogy that helps our four dimensional brains try to make sense of a phenomenon that we are presently unable to make sense of? Are the two particles actually one in a dimension of which we are unaware, so that they are not distant from each other in that dimension but, rather, "touching" (yet another analogy, I guess)?
I think they just didn't want to risk youtube age-restricting the video on the off chance that it was dead. Opening the box beforehand would have ruined the experiment.
Oh No! The Mammals are all alike even extinct ones. Entropic empathy is illusion of expectation or latency in lactating this case not weighted 🤦♀️🤷♀️
Perhaps you are quantumly entangled with him, such that when he knows, you don't know? The when he wishes to know what you know, he is lost, but you know :|
That is just what I thought. Analogies are wonderful when they are accurate but simpler, such as liquid flow through pipes in analogy to electric circuits in classical physics.
I for one am astounded and amazed at these teaching skills- I can´t believe that I- as a somewhat logically challenged and abstract minded and scatterbrained layperson- managed to follow through this lecture and actually felt like I grasped the concepts! Well done!
A lot of the confusion is due to a tiny omission: the same coin in the same box always produces the same animal throughout the thought experiment. This isn't intuitive in the realms of symbolic logic. (I don't think the "NB" solves much, since even it doesn't explicitly state that that output will always be the same if the coin and the box in question are the same.)
Before the big bang, all the space time, and energy and mass that we observe today was crushed in a tiny quantum state. So doesn't this mean that entire space is entangled ?
Good point. They WERE entangled, but breaking the entanglement is really easy. Other forces affecting the particles (which are largely photons or electrons) is really easy when other particles and/or forces act on individual ones. Remember, if something affects one particle, there is no "spooky action" on the other particle.
@@ajit_edu They have done calculations on the likelihood, and with inflation, etc the chances of any original particles being entangled is virtually zero.
As commenter 'allmhuran' pointed out, the rather offhandedly included line, "NB - these are simple, unconnected mechanical boxes with one given output (animal) per input (coin)" was the single thing that had to be understood (and should've been explained) to make this analogy sensical.
Thank you Phil. I also didn’t understand the example in the initial lecture, so I found this and now understand it. This is a fault with me not you. If my brain was a bit faster I would have understood it in the first place. QM is one of the most fascinating disciplines I have ever ventured into.
am still slightly confused ; just means i was paying attention. most coherent, concise explanation delivered in a very pleasurable voice. thank you, truly, for making and then sharing this video with us. let us watch and be nourished
First of all Thank You so much for taking your time and explaining most of the misunderstood parts but.. the last 6 mins of the video was again not to point it was just facts with no proof and also you forgot to explain why it is 85percentage and the idea or the rules which made it 100 percentage . Thank you
I see it as a plug for a very likely Great Book, I think we are in a real world where more money is paid to a CEO of a minor company than any Nobel from Demark. have fun q
Can someone explain this to me. IF Bob puts in a two-euro coin then his outcome will be dependent on what Alice puts in her box. If she puts in a one-euro coin it will produce rabbits, but if she puts in a two-dollar coin it will produce a rabbit & a dog. So Bob's output in this case is dependant on Alice's input and that means the boxes will already have to communicate the inputs to be able to accurately produce the output that satisfies the conditions. I think I'm missing the point
Great talk. And I like the final point a lot. Quantum mechanics is a window into a deeper theory, one where either time or space is emergent. And this 85% limitation may be a clue about what lies beyond it.
There is no such thing as time. It's a human invention based on the rotational period of the Earth. Psychological time is something we have developed related to our ability to store information in our memories but it too is an illusion represented as past and future. The only real state is here and now. Einstein was wrong when he claimed time can dilate. The inventor of the atomic clock, Louis Essen, claimed Einstein did not understand measurement. He also claimed relativity theory developed by Einstein is not even a theory, but a collection of thought experiments. Einstein arbitrarily added a multiplier to time in equations like s = vt to make it s = kvt, with no proof of that condition. it means not only time can change but distance too, as velocity increases toward the speed of light.
@@arctic_haze ...these are not my views, they are fact. Time was invented by humans based on the period of rotation of the Earth. A period is not defined on time until someone supplies unit, like seconds. If you can find a phenomenon called time independent of the rotation of the Earth, please post it. Meantime, please consider why we have two forms of time, solar time and sidereal time. One is based on the exact period of rotation of the Earth from noon to noon and the other is based on the period of rotation wrt the stars. That's because the Earth moves a considerable distance around the Sun during a day, therefore one day is longer than the other. Then you might consider why time has an analog in the distance traveled by a point on the Equator. Time can also be expressed in minutes and seconds (arc length) and not in seconds of time. Therefore time can be a distance as well. I have discussed this with physicists. Some agree with me and the others become frustrated when they cannot find a time independent of the Earth's rotation. There are sure it is there but they cannot point to it.
basically, the way the experiment is set up, you solve the appropriate quantum mechanics (QM) equations and the 85% comes out naturally. the 75% predicted by hidden variables (HV) is a purely logical approach. the conflicting predictions come from this logical approach vs the QM equations. there are even more rigorous tests of HV vs QM out there, where HV predicts 0% but QM predicts 100%... QM always wins
Yes, see below. It is called the Tsirelson bound, and arises simply from the way Bell correlations are set up: en.wikipedia.org/wiki/Tsirelson%27s_bound
@@9erik1 No. The 85% is from the error factor in the observations. Not actual reality. If you could observe 100%, then you could observe all state variables without influence and QP waveform collapses to a fixed value. It drops out of QM into plain ol' vector mechanics. No more hocus pocus.
@@jamestheotherone742 nah what I'm saying by the 100% thing is that there are certain bell experiment setups where HV never permits a certain result, whereas QM ONLY permits that result
Quantum is the word that some day Scientists would equate with Cosmic Intelligence. We are waiting for that day to come. Thank you for your interesting talk Dr. Phillip Ball.
At 9.14 it is very confusing. Why do you automatically show rabbits appearing for Bob in Alice’s 2 pound column? By your rules a 2 pound from Alice and a 1 pound from Bob could give two dogs, or two rabbits. Not clear to me even after several rewinds of your explanation.
I've studied Special Relativity since I was 15, some 59 years ago, and found it to be logical, but to this day even with an M.S. in Physics, I find quantum mechanics, at least the way it is interpreted today, to be odd (spooky, if you like). The difference is that Special Relativity does not have the random unpredictable nature of QM. Even though it works, QM still leaves me with an unsettled feeling.
@@wayneyadams I think that's probably because you think humans (smart ones) should be able to understand everything in our universe. Reading Kant's Critique of Pure Reason made me understand that our available logical concepts need not be, and probably aren't, all the logical concepts there are. So until we evolve into higher beings, we are stuck.
@@robertbrandywine The point of my comment was that QM flies in the face of reason. It's a concept that seems like it can't be true and yet all experimental evidence seems to indicate it is. I agree that our puny little evolved ape brains probably are not at the point where we can truly understand the universe around us.
To all making comments about the lecturer: this is the Philip Ball, the author of a phenomenal book Critical Mass: How One Thing Leads to Another. This mind blowing book is a must read for anyone even remotely interested in science and how this world really works.
The subject is scientific therefore you might need to pause the video and work it on your head. I had to come with this array of results by my self to understand it fully. And its actually an easy concept. Its a video after all. Use the advantage it provides such as pause.
Care to explain how you verify that both entangled particles collapse at the same time, when measuring one of them? If you measure both of them simultaneously they would have collapsed even if they were not entangled. If you measure one and not the other, how do you know that the other did in fact collapse, and did so at the time of measuring the first one? If you measure the other one later, you still would not know when the collapse took place.
It's just the result of certain types of interactions which have certain constraints based on conservation laws, but certain freedom within those parameters.
I don't think particles can change their entanglement. Once they "interact", there are effectively new particles coming out the other side of the interaction.
Rahul Jain ok, so it is kinda like a one way function. With this I think the term ‘entangle’ is misleading. Seems like the term should be changed to be more descriptive and consistent. I feel confident I’m missing something here since scientists agreed upon thus term. I’m still puzzled how two entangled particles can be derived from one source particle unless the two are halved from the one.
@@Elfdogable Particle count is not a conserved quantity. A single photon can split into an electron and a positron, for example. Their wave functions are entangled with each other. One particle's values are based on the values in the other equation and vice versa.
True love is a great example of quantum entanglement where two people can become entangled throughout a lifetime - it's amazing that all we really learn in life is love; what is love, how to love and who we love but nobody educates us about this, not even the Royal Institution!!
Unfortunately Quantum does not exist and never has for science has proven that the smallest particle in the universe is the proton. Popular Science has even proven that they do not know what an electron is or even light. They have recently proven dark matter and energy does not exist. And the large colliders have proven that given enough energy a proton can be destabilized back into energy. The quantum particles are actually decaying matter back to energy. That is why these quantum particles only exist for Pico seconds or less! This is actually the time it takes for complete destabilization.
When I think about spin up and spin down, I think of a seesaw, where one end spins about a pivot, so that the opposite end is always the inverse and never the same. So I have a question: If I push up at one end of an arbitrary seesaw, does the other end go down instantly? Is there a delay in the force applied or does this force travel at a finite speed? What if this pivot approaches an infinitesimal point in size and the seesaw is contructed by an infinitesimally thin line of arbitrary length passing through the pivot - would pushing one end up instantly push the other end down? If there are two entangled electrons analogous to a pivoted seesaw as above, maybe we should be looking for the pivot?
Your comment made me think of another way you can think of what you said: If we have a 1 meter stick, the moment I push it from one end, the other end moves immediately. Now, what if we had a 1 km stick, pushing from one end, again affects the other end immediately. Anyone on the other end, would see the stick move immediately as soon as I push or pull it no matter the distance.
@@Littleprinceleon Thanks for the answer to the thought experiment. I considered your reply to be accurate, as I was thinking the same when I posted the question way back then. However, since the spin up/ spin down happen instantly, the maximum speed of EM through the material cannot be what is happening as this isn't instantaneous. I'm thinking of a 'time pivot'. If you consider a pair of anti-matter/ matter particle creation, which happen instantly, and think of the anti-matter as the same particle as the matter particle but travelling backwards in time, then with a similar principle we can also apply this to entangled spin up and spin down as the same particle. When spin is observed with two entangled particles, one can consider the other as the same particle but travelling back in time. Both types of systems are connected with a 'time pivot' and are the same particles but with the 'other' particle travelling back in time. These systems when observed, collapse the wavefunction and give the impression that they are happening 'instantly' and the mechanism travelling faster than light/ EM.
That is one of the best talks I've seen and heard. I studied QM at Uni, and his talk gave me a real insight into what I learned through number crunching the equations, but not really being able to form some sort of mental picture about what was going on in that weird QM space. It really is like a "Fairyland of Weirdness", if you study it. It's better than The Adventures of Alice In Wonderland. Bells Inequality and Bell's Theorem are mind bending concepts to get one's head around.
Oh No, the analogy example was awful, not the e explanation! The author should have come with a different example or best would be to explain simply the real experiment. Trying to explain the same bad analogy again in a longer detailed video is pointless!
Excellent explanation of a difficult concept . Perhaps explaining how the " rules " of this scenario apply to the quantum world specifically would wrap things up neatly .
My favorite demonstration of entanglement is when you use polarized film to break reality. Step 1: use polarized film to block ~50% of the light coming from a light source. Step 2: use a second sheet of the Same kind of film placed perpendicular to the first to block ~100% of the light coming from the light source. Step 3: use a third piece of the Same polarized film and place it between the other two (currently blocking ~100% of the light) to block ~85% of the light, breaking reality into pieces!
First of all: we have to emphasize that the light gets polarized in some direction from the first filter. The perpendicularity of the second is regarding it's polarization angle! Then if you place the third in any angle over the previous two: no light is miraculously renewed from zero light energy. You have to place the third filter at 45° between the previous two: so you reorient the polarization from the first filter! This new polarization is no longer perpendicular to the second filter (but at 45° angle).
@@Littleprinceleon True, in between, is correct. But it still beggars belief. Not only that, but every filter you add between the first two that isn't aligned with another filter, decreases the effectiveness of the original two. That's still something that blows my tiny mind!
Definitely something going on when we turn our attention to measuring quantum objects, the double slit experiment also, our thoughts change particle behaviour somehow. Thankyou very much for hashing it out a bit more, it is a mind blowing concept, letting go of preconceptions and being amazed but something that is measurable and real is refreshing.
Just because they are observed as two separate particles isn’t it possible that they are still the one in a sense. No transmission needed , whatever happens to it happens instantly .
Ok, let's take a thought experiment. It's a wartime situation where two generals - a 3-star and 1-star - are each in charge of half of an army. They have a static enemy in front of them and want to attack in a pincer attack from diametrically opposite directions. They know the enemy has spies listening to all their tactical discussions and communications between the two generals. They know then the enemy will arrange their defenses to meet the two pincer attacks if they know for certain the compass direction from which the two attacks will take place. They will thus prepare for this pincer with half the defenses facing out toward the respective half armies. If the enemy does not know from where the generals are coming, then it will have to distribute the defenses around the four points of the compass and so be weakened in its defense. To defeat the spies, the generals decide to make their decision only when they reach the North and South positions and only decide then whether to attack immediately OR suddenly change and attack from the East and West. They cannot communicate which they are going to do as the spies will intercept the communications. The generals thus take one entangled particle each and agree that if the 3-star general in the North at the appointed time has a downward spinning particle then he will indeed veer to the East and the 1-star seeing the opposite spin in his particle will veer to the West. However, if the 3-star general has an entangled particle spinning upwards, then they agree that at the appointed time they immediately attack from the North and South. The information about the direction of the pincer attacks will take place has therefore passed between them INSTANTLY and without communication - and so fooled the spies. AND at a speed greater that the speed of light Where have I got this wrong? Jim Murray
Familiar with the subject, yet I couldn't follow the talk. Probably an out of context edit? Maybe it would be a good idea to leave aside Alice, Bob and weird imaginary boxes with strange cooked-up rules, and just state the facts. Nobody needs coins and rabbits here. Those are just adding confusion. It is not a board game with strange invented rules, it's reality, so start by describing real experiments and their results, and build from there. Only afterwords start discussing what abstract rules might be in place, so we see such experimental results.
I am also familiar with the subject. I could not follow the logic and get the same matrix. Did he leave out some bit of information or perhaps I did not understand the rules. Was anyone able to get the same matrix?
Any entanglement demonstration involving a choice illustrates that the subjective experience of scientist A making a choice, only he knows, violates locality as observed by scientist B, and so the subjective experience of scientist A does not occur in a finite box. Therefore, the human mind cannot be said to be inside a finite box such as the brain, the brain and body, or the body and the local environment regardless of how entanglement works.
@@robknight9406 a nondimensional void? no time. no space. no matter. just symmetry. virtual nothing balanced out by virtual nothing. our universe came out of a nondimensional void (by means of a random quantum fluctuation) and the time space dimension is still unfolding at the edges. the big bang is still happening.
we have taught that while creating entanglement between 2 particles via photon there is conservation of charge which means if a particle have positive charge the other would have negative charge, there is also conservation of spin which means that if one particle have up spin then the other must definitely have down spin .These r the 2 conditions to justify that 2 particles r entangled or not and there is conservation of charge and conservation of spin because to produce the net effect zero as photons don't have charge as well as spin . But the interesting thing here is to note that that there is no conservation of mass between the 2 particles so as to produce the net effect zero as photon mass is zero. My biggest dought which implies that if there is no conservation of charge that particles (not photons) cant be entangled at all. If anyone get some info about this pls inform me in the replies section.
Keep in mind the pencil through the paper worm hole analogy when I say. This is consistent with quantum particles being 4d items while atoms are the 3d effect of those particles. Like a flock vs birds. Since we are made of atoms we can not see the 4d universe.
That is totally NOT what physicists say. You can entangle, disentangle particles (Electrons or Photons) at will with simple benchtop equipment. There are no special "quantum particles"
@@dnomyarnostaw If you think you've made a point on my comment then you best reread it because your statement is in no way relevant to what I was talking about.
@@lucidmoses "quantum particles being 4d items" ..is just nonsense. We are talking Photons and Electrons. Very little else is used as a Quantum particle. Calling Photons and Electrons "4d" is just woo.
@@dnomyarnostaw ".is just nonsense." Ok, prove it. Or are you just making up assertions. I on the other hand I was careful to summarize and get it right. The least you could do is read what I actually said and argue against that.
Great talk, it makes one think. To me it exposes the issue with only having 4 dimensions, X,Y,Z, and t, and it sort of steers one into the idea of extra dimensions, these being the ones of particle interaction. Say A,B,C, and d are dimensions in which very specific particle properties exist or are modified through, and in this dimensional reality distance and time (or whatever they are) are completely different than XYZt. The abstract idea of extra dimensions can make more sense if we can relate them to things in our own tangible dimensions. It may even be possible to map other dimensions based on these "spooky" particle relationships. I've always had an issue with the idea of extra dimensions, the concept makes no sense, but this talk gets one wondering.
Sometimes you get a lecture that 'clicks ' when the explanation just fits with stuff you have heard before. I was lucky to experience this from this lecture. I nearly 'lost it' at the Alice and Bob box analogy, My big takeaway was confirmation of the 'no spooky action' understanding.
What about the concept of reverse time dependency? The idea that in normal situations past events influence the future; but, for entanglement somehow future events can influence the past.
there is peculiarity in those particles, they travel at speed of light, what ever is connected between them since the beginning, will remain connected, it's kinda freezes gravity or electromagnetic field that remains constant between them creating one dimension or one piece that collapses when we measure them, because time start to run again, it switches to our dimension, gravity wouldn't allow them to travel at speed of light in the opposite directions if they are connected by gravity, somehow gravity must gain energy as they go apart. It's hard to correlates distance and time, it seems like the particles goes back in time for us as an observer. In other words, if we put two particles in the opposite sides on a balloon, they go apart as the balloon inflates, the act to measure one particle is when we break the balloon, they disconnect immediately, the time is much shorter then it takes to get them apart, the energy releases much faster, space time crashes the whole structure.
Has anyone considered quantum entanglement uses the gravitational force of the black wholes that connects the entire galaxy and holds the stars of the entire galaxy in place. Creating an entanglement resonance frequency and depending on how you entangle you can get the same or opposite behavior of the two particles 1. By using physical space or 2. by using wholes in the clear sheet like the black whole itself, I called it the black sheet because it is black whole energy, however that implies a light and darkness theory when it's not, it's a clear sheet of energy that is using black whole energy in physical space, or wholes in the clear sheet that the black whole basically is. So one way of quantum entanglement resonance frequency sending you get the same behavior the other you get the opposite behavior. Physical space you get the same behavior, wholes past physical space or the sheet you get the opposite behavior. And you can quantum entangle particles into physical space entanglement or into a whole's in physical space entanglement and use the same black whole energy at the same time not depending on what side of the clear sheet of physical reality and non physical reality you entangle the particles. Or possibly opposite behavior happens if you entangle or code the particles so they are entangled, although one is entangled into physical reality, while the other is entangled into a whole in space, then particles will respond in opposite behavior. And if you encode an entanglement where both electrons entanglements exist in physical reality or both exist in wholes in physical reality they will behave the same.
Here is simple example to understand entanglement. (Perhaps this may not be the best way). Suppose two people conversing with each other using a mic. Both are from different country. 1st person: I'm a British but my mic makes my accent seem like a Japanese. 2nd person: But I find your accent to be like an Indian. 1st person: Then perhaps it's because of your speaker. You can find the co-relation with this between the speaker and mic. And how it effects the actual sound of both.
The explaination is always how entaglement works, that has been stated over and over again. What always seems to be passed over is why particles gets entagled?
I believe it’s because of energy states. It’s probably easier for two particles nearby each other to be in opposite spins than the same. Opposites attract and similar repels. Opposites are always opposites no matter what so they become linked
"Shared information," "quantum nonlocality," "spooky action at a distance." Asserting that those are different feels like playing with semantics to me. Any way you slice it, the effect is getting from A to B faster than light. Recently there's been the whole ER=EPR thing, equating entanglement to "wormhole like" connectivity between places in spacetime. Well, again that's just another angle to approach the same point from - it implies a "shortcut" from A to B, but that's just tinkering with distance rather than tinkering with time. The end result is the same. The best explanation I've seen is in Christian Baumgarten's paper, "How To (Un-) Quantum Mechanics." He models reality as an arbitrary collection of state variables that are functions of *time only*, and then makes one assumption: that there exists a single function of those variables that is conserved as the variables change with time. The mathematical analysis that follows shows that three spatial dimensions and most of the modern laws of physics "emerge" as necessary consequences. Some interactions that occur within this framework depend on those emergent spatial dimensions, and those are limited to a maximum speed (not one put in by hand - that speed limit is also a consequence of the analysis). But other interactions do not depend on the spatial dimensions; they have nothing to do at all with space. So they are not subject to any such speed limit. This is where the "instantaneous" connection between degrees of freedom comes from in Baumgarten's picture of the world. Note that the "time parameter" that these variables depend on is not any particular observers "personal time" - observer time would enter in as another emergent property. The "master time variable" is a single independent thing, and there's no funny business about it. Also note, though, that this master time variable isn't necessarily "accessible" to physical observers residing inside this "reality." It's an attribute of the model only.
I've sat down with a pen and paper to try to follow the analogy, but for the life of me I can't. (EDIT: I finally figured it out, see reply comment.) At 9:25 we're told that the combination of rules require a rabbit to emerge from Bob's box whenever Alice puts £2 in her box, but that doesn't seem to be necessarily true. Let's consider the case in which Alice puts £2 and Bob puts £1. Rule 1 only applies to situations in which Alice puts £1, so it doesn't tell us anything about the case we're considering (as Alice has put £2). Rule 2 only applies to situations in which both have put £2, so it also doesn't tell us anything about the case we're considering (as Bob has put £1). Rule 3 states that all other combinations (i.e. (£1/£1), (£1/£2), (£2,£1)) produce either 2 rabbits or 2 dogs. This includes the case we're considering. This rule, however, doesn't state that Bob must get a rabbit. It merely states that both boxes will produce the same thing, whether that be a dog or rabbit. So, there seems to be no reason to think a rabbit must come out of Bob's box in the case in which Alice puts £2 and Bob puts £1 at 9:25. The same kind of reasoning applies to the case in which they both put £2 and, again, the rules express no reason why a rabbit must come out of Bob's box in that case either.
I've done some digging, and finally found the answer to this problem. Here's how it works: The first thing we need to observe is there is a less-than-obvious 4th rule (an assumption of locality) in parentheses at the bottom of the list of rules: The boxes have no way of communicating with each other. So, Bob's box must produce an output that accords with all the rules, knowing ONLY what coin was put in by Bob (and without any information about what Alice put into her box). Now we can return to the case in which Alice puts £2 and Bob puts £1. According to the 4th rule, Bob's box knows ONLY that he put in £1. As far as Bob's box knows, Alice MAY have put £1 in her box (even though she actually didn't). That means Bob's box knows that it must be in one of the two cases in the top row, but it doesn't know which column. So, Bob's box must now consider what output options are available to it that conform to all the rules REGARDLESS of which of the two situations it might be in. First, it considers the possibility that Alice put in £2. In this case, the only rule that applies is rule 3: the outputs of the 2 boxes must either be both rabbits or both dogs. In this case, then, Bob's box could produce either a dog OR a rabbit. Next, Bob's box considers the possibility that Alice may have put in £1. In this case, both rule 1 AND rule 3 would apply. Bob's box knows that, according to rule 1, Alice's box would have produced a rabbit, and, according to rule 3, both boxes must produce the same thing. SO, if this turned out to be the case, Bob's box would have to produce a rabbit. In both cases Bob's box could produce a rabbit while conforming to the rules, but only in the first case could Bob's box produce a dog. Since Bob's box can't rule out that the first case isn't the actual case, it has to produce a rabbit.
I saw the talk a while ago and didn't understand the boxes. Now you've told it here again... and it makes no sense what so ever as far as I can discern. Truly, I think that people should just admit that they don't yet understand the quantum scale and how things work there.
I could not follow the logic with the boxes. I could not use their rules and get the same results matrix. the rules seemed fairly simple. I must be missing something. Did anyone reproduce the results matrix from their rules? Please let me know.
Philip Ball is one of the few people in foundations of physics who recognized the value of the quantum reconstruction program (QRP) early on. He was advocating for that approach as early as 2009 in a RUclips video and shared Dakic and Brukner's information-theoretic reconstruction in a RUclips video on quantum entanglement years ago. Well, it turns out Philip was prescient. Quantum information theorists have now rendered quantum mechanics (QM) a principle theory based on the relativity principle exactly like special relativity (SR), which shows QM is as complete as possible and totally compatible with SR (many believe quantum entanglement renders QM at odds with SR). With that understanding of QM one can rule out the existence of Popescu-Rohrlich joint probabilities (the PR-box) because they violate conservation per the relativity principle. We explain that in "Why the Tsirelson Bound? Bub’s Question and Fuchs’ Desideratum" Entropy 2019, 21(7), 69. We explain the conservation principle itself in "Answering Mermin’s challenge with conservation per no preferred reference frame" Scientific Reports volume 10, Article number: 15771 (2020). [Those are open access, but I can't provide the links or RUclips will delete this post.] Those articles are a bit technical, but we have it all explained for the "general reader" forthcoming in "Einstein's Entanglement: Bell Inequalities, Relativity, and the Qubit" due out in June 2024 with Oxford UP (see Chapter 8 specifically for the PR-box). Here's a brief summary. The mystery of quantum entanglement arises because we are looking for a 'causal mechanism' behind its correlations, what Einstein called "constructive efforts." Einstein was faced with a very similar situation concerning constructive accounts of length contraction (and time dilation) to explain the Michelson-Morley experiment. Einstein wrote: "By and by I despaired of the possibility of discovering the true laws by means of constructive efforts based on known facts. The longer and the more despairingly I tried, the more I came to the conviction that only the discovery of a universal formal principle could lead us to assured results." That is, he gave up looking for causal mechanisms ("constructive efforts") that would shrink meter sticks and slow down clocks to fool everyone into measuring the same value for the speed of light c, regardless of their relative motions (an empirically discovered fact known as the light postulate). Instead, he said c is a constant of Nature per Maxwell's equations, so the relativity principle -- the laws of physics (including their constants of Nature) are the same in all inertial reference frames -- demands that everyone measure the same value for c, regardless of their relative motions. The Lorentz transformations of SR follow from the light postulate as justified by the relativity principle. As it turns out, the same opportunity for QM has been provided by quantum information theorists. That is, they have reconstructed QM based on an empirically discovered fact called Information Invariance & Continuity that (in non-information-theoretic terms) means everyone measures the same value for Planck's constant h, regardless of their relative spatial orientations. How does that solve the mystery of quantum entanglement? Suppose you send a vertical spin up electron to Stern-Gerlach (SG) magnets oriented at 60 deg relative to the vertical. Since spin is a form of angular momentum, classical mechanics says the angular momentum you should measure is (hbar/2)cos(60) = hbar/4 in that direction of SG spatial orientation. But, the SG measurement of electron spin constitutes a measurement of h, so everyone has to get the same +/- hbar/2 for a spin measurement in any SG spatial orientation, which means you can't get what you expect from common sense classical physics. Instead, QM says the measurement of a vertical spin up electron at 60 deg will produce +hbar/2 with a probability of 0.75 and it will produce -hbar/2 with a probability of 0.25, so the average is (hbar/2 + hbar/2 + hbar/2 - hbar/2)/4 = hbar/4. In other words, quantum mechanics says you get the common sense classical result on 'average only' because of the observer-independence of h. Now suppose Alice and Bob are measuring the spin singlet state (the two spins are anti-aligned when measured in the same direction) and Alice obtains +hbar/2 vertically and Bob measures his particle at 120 deg relative to Alice. Obviously, if Bob had measured vertically he would have obtained -hbar/2, so at 120 deg Alice says he should get hbar/4 per our single particle example. But of course, Bob must measure the same value for h that Alice does, so he can't get the fractional value of h Alice says he should (otherwise, Alice would be in a preferred reference frame). Instead, his outcomes at 120 deg corresponding to Alice's +hbar/2 outcomes vertically average to hbar/4 just like the single particle case. And, of course, the data are symmetric so Bob can partition the results according to -*-his-*- +/- hbar/2 outcomes and show that Alice's results satisfy conservation of spin angular momentum on 'average only'. In the end, Alice partitions the data per her +/- hbar/2 outcomes and says Bob's results must be averaged to satisfy conservation of spin angular momentum while Bob's partition shows it's Alice's outcomes that must be averaged. This should remind you immediately of an analogous situation in SR. There when Alice and Bob occupy different references frames via relative motion, they partition spacetime events per their own surfaces of simultaneity and show clearly that each other's meter sticks are short and their clocks run slow. In other words, the mystery of quantum entanglement resides in 'average-only' conservation that results from "no preferred reference frame" (NPRF) giving the observer-independence of h (NPRF + h). And, the mystery of length contraction resides in the relativity of simultaneity that results from "no preferred reference frame" giving the observer-independence of c (NPRF + c). Give up your constructive bias for QM just as is done for SR and physics makes perfect sense. But, the implications for your worldview are profound; you have to accept that physics is most fundamentally about constraints on the 4-dimensional (spatiotemporal) organization of worldtubes per NPRF + c and the distribution of quanta therein per NPRF + h.
I keep thinking that quantum waves and ghosts are related, two sides of the same coin. Like yin and yang. It's the only conclusion that makes sense. Remember that nature uses the least action principle. The universe is inheritance lazy. But there is no reason to disallow a complex life form of very low energy content. QM should predict the existence of ghosts. A ghost is a special kind of wave function that has free will, consciousness, but has to creep between potential energy wells to move around. If you don't see it, then you are being intellectually avoidant.
But the ghost has to be made of something. Specifically, something that interacts with light sometimes. There's no real evidence of ghosts, aside from crackpot supernatural shows and fake videos.
Quantum entanglement is really about the stability of the dynamics of energy. Mathematics can make anything be stable as the same formula with the same data will always deliver the same result, but is nature also that mathematically stable. Two particles interact and develop a dynamic position relative to one another which maintains indefinitely because there is no drag variable to alter that dynamic correlation. The fuzzy part of the quantum entanglement discussion is that it implies that if you observe one entangled particle then the other particle some how freezes to allow the observer time to find the other particle to take a look at it. Correct me if I am wrong but I don’t think that is what happens.
Hi Mr. Philip. I have to say you did such a fantastic job explaining this and it just feels awesome listing to you talk about this topic. I really love physics so much but never gone beyond first year university physics. But I think I have a great real life example of quantum entanglement which I think is really true. I have a little 3 year old daughter. And whenever I think about her I can feel exactly what she is doing. It's totally like the quantum entanglement. When she was a baby every time I would think about her she would start crying. And this was so strong I said to my self I'm going to stop thinking about it. It's hard to explain but in my view entanglement doesn't have a physical "explainable" property to it. But I think a mother/daughter thoughts are entangled. And no matter where she is in the world I can be thinking and knowing exactly what she is doing.
jordan cox honestly I’m taking an astronomy class which opened my eyes to all of the stem fields and the brilliance of it all. I’m going to be an engineer now
1:15 "What happens when two particles interact. It has to happen." Okay, what particles? Just electrons? photons? Also what does 'interact' mean? (I'm not so much asking the question to get an answer but hoping to help fine tune the explanation. I've been reading this stuff for decades, and some of it is still very difficult to understand. I also know, both as a teacher and a nerd, that refining an explanation is an important aspect of any scientific advance. Example: Einstein's ideas.) And how is spin measured? And if making the observation affects the condition, then if the first measurement has something to do with 'locking in' the spin of the interacting particles, than what happens at the other end (of the experiment. time or distance or both) when the second measurement is taken? As a teacher I'll come up with something that I'm absolutely sure is elegant, brilliant... and my students shrug. Six months later I'll look at it again, smack my head, and realize I'd left this bit vague or confusing (but then six months or a year after that.... ) I like the glove analogy and the simple chart. And the 85%. thank you
Hold it with the lies. Nobody understands entanglement. The truth is this is what happens. It's spooky, bazaar, can't possibly work that way but it does. That is really our understanding of it.
The truth is that we don't understand what's happening - so there is no way you can say "The truth is this is what happens" The particles are related and have common attributes - but we can't change one and watch the other change accordingly.
leaps right over explaining why any connection or hidden variable would be needed (as does every video on this topic). no explanation of that at all. if I slice a globe into N/S halves, and send one away, then measure that mine is N, I can know the other is S with no telephone, no hidden info, no secret connection. it's just the other half.
At 10:48 Alice's box alters its output depending on which coin Bob put in. At 11:25 Bob's box receives a signal telling it what Alice has put in. To be consistent, he should have said that Alice's box receives the signal from Bob.
But, if that's the case, and it works under Quantum Entanglement, doesn't that mean you can have FTL communication by deciding what to put in Bob's box to influence Alice's box?
"When we observe it..." Isn't this always the misleading phrase? Shouldn't it be "When there is an interaction..."? Whether we observe it or not? Whether we measure it or not? Why imply that we somehow have to be part of what makes a wave function collapse? When surely they collapse all the time all over the universe far beyond any possible role we might have in them doing so...
I guess because it collapses 'whenever' we observe it. That is what prompts d phrase 'when we observe it'. It is not misleading bcos observer collapses the wave function does not imply that 'sumthing' else doesn't collapse it. It simply implies that 'observer collapses the wave function.'
@@drphosferrous yes!! And that maybe completely true. But i guess the thing is a conscious observer collapses it 'for sure'!! And thts wat needs to be looked at too i guess.
@@SanchitShettyTantraYoga i suspect that when "information" is better understood in physics,general relativity will reconcile with these quantum spookularities.
@@drphosferrous yea mayb. But whats interesting is that even though science may not accept the entitative existence of the witnessing principle, it is still interesting to understand that this Universe with all its complexity had the potential to create and also indeed created an observing principle like d human mind wich can observe and understand information. I think a time will come when instead of trying to focus on the small particle which we are trying to understand, humans wud start focusing on tht 'entity' , tht principle wich is actually understanding information!!! I dunno for sure though but sure looks like it wud go that way!
Since quantum entanglement is outside of time does that not mean everything in existence is technically still entangled with each other because it was so in the beginning?
One question regarding the "action at the distance" part and how it's not a thing. It seems that saying that two particles are the same is overlooking the part that they remain connected no matter the distance between them. Meaning that the factor of the distance not mattering seems to be overlooked or, at least, de-emphasized by simply saying they are one object.
Not sure why physics has become so dogmatic in the last 20-30 years. What if Special relativity doesnt apply in all cases? Maybe space/time is an illusion and there is really no separation between the entagled particles!? We assume same rules for Gravity apply everywhere in the Universe with the same constants and then we 'invent' Dark Energy/Matter which we havent been able to detect. Same way we 'invented' the INLATION theory (post Big Bang). I hope the young generation of Physicists/Mathematicians is looking at other options to explain some of these Quantum phenomena without the Dogmatic assumptions.
Well said...It seems it's the physicists who "think outside the box" are the ones who make the breakthroughs. They/we are obviously missing something. (a lot actually. lol). A very complicated universe underneath the veil of apparent solidity : )
Many younger physicists are coming up with new & better theories' unfortunately like any other institute, the mindset & beliefs of established scientists are very hard to change. Often changes only comes about when all the old farts die off.
It's a bit like attaching Alice to Bob with a pole. If Alice pushes her pole, Bob will instantaneously feel the effect. There is no issue with transmission between objects because there is no transmission: Alice, Bob and the Pole are connected and thus, in that moment, the same object. That doesn't resolve the problem of the nature of the pole itself (where is it?), but it does address Einstein's transmission dilemma.
I don't see any difference between "two things being one thing" or "spooky action at a distance" or "signals moving faster than the speed of light". It's six of one or a half dozen of the other.
No it's not. You cannot use Quantum Entanglement to send information faster than light. This is because the spin of a particle is random. If you could produce a spin of oyur choice then you could send information faster than light using quantum entanglement
@@EinSofQuester i tot it did not send the info? that's why he said don't listen to that "spooky action" thing... what he meant was, it become the same thing... it doesn't sync via sending info, but it's just the same thing after entanglement.
I would try framing this as a contradiction: "entangled particles are non-local, while also being local" Contradictions can often be solved using the 'principle of separation'. e.g. maybe the entangled particles are non-local in the three spatial dimensions, but they are right next to each other (or even fused) in some unobserved dimension?
Entanglement is a form of measurement. Bell's Theorem assumed that entanglement excludes quantum tunneling which could conserve the speed of light. The question that is being begged is, "What is the nature of form?" Put in another way: Is there a dimension only accessible to entangled properties in which all points in the universe are equidistant? (i.e. appear as 1 dimensional such as the propagation of electric charge)
So I am trying to come up with simple analogy using spinning coins. Please correct me if I am wrong! Imagine having two coins on table. Face one Head up and the other Tail up. Now start them spinning at the exactly same time with the same force like beyblade. It is not Head or Tail till its spinning, so to stop them you slam your palm on bot of them at the same time. Now when they are not spinning any-more you can see one is Head and other is Tail (or one Tail other Head depending on moment you stopped them). Makes perfect sense. Now the interesting part... Spin the coins again, take one coin far away from the other but make sure the coin doesn't fall and keeps spinning. Then slam your palm on only one of the coins and strange thing will happen, the second coin (no matter how far away) will fall at the exactly same time no mater the distance . Also once you stop the coins the entanglement is gone and they are now just ordinary coins. Am I right?
@@karthickpn450 A large disc resting on the backs of four huge elephants which are in turn standing on the back of an enormous turtle. You know it makes sense.
10:21 Are the rules intently violated though? Why in the upper right case there is a dog and a rabbit: Bob puts one pound, Alice puts two pounds; any case that doesn't have two 2 pounds results in either double bunny or double dog; so the upper right case it should be that; either double bunny or double dog no?
Simply saying that the boxes are no longer separate objects doesn't explain how they communicate from opposite ends of the galaxy in defiance of relativity. Whether they are at opposite ends of the galaxy or across the room from each other, saying they are one object doesn't erase the need for the signals, information, thoughts (whatever you want to call them) to traverse that space.
I seriously understood how this all works yesterday .. after watching this video, I no longer understand it and have thus as a result de-learned it. "Spooky unlearning at a distance" .. appreciate the effort but the math explanation is simply easier to understand.
This is a very good exposition of the CHSH inequality. It may not be obvious to some viewers that Alice is allowed to employ a randomized strategy wherein her £2 randomly draws a dog or rabbit, but they still can’t exceed 75%.
Great video. Quantum entanglement is still a mystery in the sense that we do not yet know why the universe allows such behavior. Quantum non-locality clearly describes the behavior, but does not explain why such behavior, over seemingly endless distances, is even possible. My idea to explain this would be to suggest that spacetime itself is quantized, and as such, spacetime particles exhibit superposition and entanglement as well. In this model, a pair of of entangled electrons is confined within a locus of entangled spacetime particles. The spacetime particles provide the non-locality property that we see for separated electrons - when actually, as far as the electrons are concerned, they are local to each other. That is, they live within the same region of spacetime - which just happens to be entangled. So, there is no violation of special relativity. If we take a moment to consider the implications of entangled spacetime, one idea that pops up is that there are additional spatial and temporal dimensions we cannot directly see - but which allow two entangled electrons to appear to be very far apart, at the time when we measure their spin. However, because they are embedded in entangled spacetime, the electrons are local to each other. It is the entangled spacetime particles in which they reside that gives us the the non-local property that we've been, perhaps incorrectly, attributing to the electrons themselves. It would be great to hear other thoughts and opinions on this topic. Quantized spacetime probably has many more implications that have not yet been explored. But this is one of them. Thanks for posting this video.
One could say that as soon as the two particles became entangled, they decided their configurations, and communicated the same at the time the entanglement was initiated. It's not like the superposition of all states MUST happen for both particles since we are not firing photons to disturb the entanglement, and resolving the configuration of one of them. If it's logical for one of the particles to have an opposite configuration to another at the time of measurement, I don't see why the particles couldn't decide on the configurations at the time of entanglement. A superposition of all states can also be seen as a "particular flavor of state", which is just another way of expressing an unmeasured entangled particle.
Suppose Alice and Bob have one reciprocally-entangled electron each, and Alice flies away to some great distance with hers, then Bob flips the spin of his electron: will Alice's far-away entangled electron also flip spin, at the very same instant? If so, when Alice's electron flips, will it release a low-energy photon? If the answers are both positive, then why should this mechanism NOT form the basis for an instantaneous digital telecoms system with zero signal-propagation delay? Also, if Alice flies away with acceleration serious enough to modify her perception of the rate of time-flow compared to Bob, then what would "instantaneous" mean to Alice and Bob in this Interstellar-like context?
This guy should be proud to be one of the best teachers around. He is able to explain complicated concepts unlike most any other person. Kudos.
At 9:14 no coherent explanation is given as to why you are producing rabbits for Bob in Alice's 2 pound column. Sure, there's a bit of word salad thrown into the world as if it was a necessity that this be the case, but given the information provided up to that point in the video, nothing compels rabbits in Alice's 2 pound column.
Note that I am not claiming that the conclusion is false. I am saying that the logic of the analogy is incoherent. It's perfectly possible to reach a true conclusion from invalid reasoning, but it doesn't help anyone else understand why the conclusion is true! I will provide the required logic to reach the (as it happens, true) conclusion at the end of this comment.
The explanation provided was this combination of sentences: 1) "If alice has produced a rabbit with one pound, then the only way we can get a dog is if they both put in 2 pounds. 2) So alice has already put in 1 pound. 3) So bob's box has to produce a rabbit in both of those cases".
Statement 1 is contains a non sequitur and is incoherent. If alice has put in one pound, then alice cannot have put in two pounds. There is no "if - then" relationship between the first and second part of the sentence because they describe two completely different cases. You can't create an "if-then" relationship between a case where Alice has put in 1 pound and a case where alice has put in two pounds.
The second part of the sentence (1) is false. It is not true that the only way we can get a dog is if they both put in two pounds. We can also get at least one dog if alice puts in 2 pounds and bob puts in 1 pound, and two dogs result. This still satisfies all three rules.
Statement (2) is just restating the premise, ie, we are looking at the scenario where alice has put in 1 pound. No problem here, but be careful with use of the word "so....". When making a logical argument, "so..." implies "what I am about to state follows from that which I have just stated", ie, it's often used as a synonym for "therefore". But statement 2 doesn't follow logically from statement 1, therefore use of the word "so..." is confusing.
Statement (3) is unclear about which two cases are implied by "both". There are two axes here, the bob axis and the alice axis. If "both" means "both when bob puts in 1 pound, and when bob puts in 2 pounds", then the statement is correct. If alice has put in one pound, then in both of those cases bob must produce a rabbit.
But in the graphic, you filled in both of those cases, AS WELL AS both cases where alice puts in 2 pounds. This is "both boths", as it were, and is not justified by the rules.
These are the reasons why your explanation is considered unhelpful. Nobody can follow the logic because the logic isn't valid.
The resolution to the invalidity is to bring in rule 4, which is the "NB" in italics in the rule slide, but which you do not actually state. That rule *seems* to mean that one box must always produce the same output for a given input. IE, it cannot be the case that bob's box can produce a rabbit on a 1 pound input on some occasions, and can also produce a dog on a 1 pound input.on other occasions. If that is the case then we cannot produce two dogs with the combination (alice 2, bob 1) as I previously suggested, because we have established that the combination (alice 1, bob 1) must produce (rabbit, rabbit) from the combination of rules 1 and 3, so (bob 1) -> rabbit, so we cannot also have (bob 1) -> dog.
But this critical part of the logic is *never stated* during your explanation.
My understanding of how we get to 9:35 is in the following steps.
Using the notation 1A for 1 pound in A and RA for rabbit in A, etc.
Rule 1A -> RA yields the table
(RA & ?) ?
(RA & ?) ?
Rule 1A&1B -> (RA & RB) or (DA & DB) yields
(RA & RB) ?
(RA & ?) ?
Rule 1A&2B -> (RA & RB) or (DA & DB) yields
(RA & RB) ?
(RA & RB) ?
Now, classical mechanics yields
(RA & RB) (? & RB)
(RA & RB) (? & RB)
The not explicit point is that we are testing classical mechanics against the rules!
Classical independent boxes imply that if we get RA then the whole column is RA, and if we get RB then the whole row is RB, likewise for D's.
The reason being that what happens in A is not affected, i.e. column invariant, from what happens in B and vice versa, i.e. B is row invariant.
That we are dealing with classical mechanics is mentioned later.
This really got me lost the first time I watched the video, I thought at that point we were just applying the rules just stated.
Incidentally, we can fill the table in 4 different ways that completely satisfy the rules IF we do not make any other assumption, but none of those solutions satisfy CM or QM.
Ergo, the rules do not replicate QM, at least as I would intend the word "replicate".
Yes, no explanation. I think though in the 2nd column it could have come out a dog or a rabbit, but they've chosen just to put a rabbit as the choice. In the left hand column, the results have to be rabbits though, that bit was explained.
yes, clear as mud
Thank you so much, I didn’t realise the NB was important and just couldn’t make any sense out of his reasonning. This makes it all much clearer, good job.
allmhuran i think it's because of the 3rd rule: you're only allowed to get a Rabbit-Dog pair from the 2p+2p case, so when A used 1p (and got a Rabbit), B will need to also get rabbits. Regardless of which coin B used, they have to get a Rabbit. So for B, the outcome is always a Rabbit, and that is actually independent of A's coin, so it will also happen when A will use her 2p coin. But i agree tbere was no explanation provided in the video, i had to pause there and think about what and why is going on...
Bro, two paticles being actually the same one regardless of the distance is actually a more astonishing explanation than spooky action at a distance.
I'm so glad you think so, because I agree. And also more correct, breaking no laws of physics.
Yes, except they have opposite properties in QM, so therefore, they cannot be the same particle
Agree with steelbluevision, this are not the same particle,
@@philipball4720 But is not the concept of the two "entangled" particles being the same object also merely an analogy that helps our four dimensional brains try to make sense of a phenomenon that we are presently unable to make sense of? Are the two particles actually one in a dimension of which we are unaware, so that they are not distant from each other in that dimension but, rather, "touching" (yet another analogy, I guess)?
@@SteelBlueVision No, they are not really "the same particle", I should have specified that. They are described by a single wave function.
Since we have moved on to rabbits and dogs, Am I to assume
Schrodinger's cat is dead?
hahaha!
I think they just didn't want to risk youtube age-restricting the video on the off chance that it was dead. Opening the box beforehand would have ruined the experiment.
Oh No! The Mammals are all alike even extinct ones. Entropic empathy is illusion of expectation or latency in lactating this case not weighted 🤦♀️🤷♀️
lool was it ever alive anyway?
@MomoTheBellyDancer It's resting!
He lost me at "hello"
ahahahah
To me these "simplified" demonstrations and analogies often make it harder to understand than just talking about what's really going on.
He lost me between “H ...” and “... o”
Perhaps you are quantumly entangled with him, such that when he knows, you don't know?
The when he wishes to know what you know, he is lost, but you know :|
Thank you for clarifying once and for all that quantum physicists are awful at analogies. :)
Why use analogies when you could use cardboards ?
ruclips.net/video/ZuvK-od647c/видео.html
It is intentional. QM has to be shrouded in obfuscation otherwise it would just be a minor theoretical field of statistical mathematics.
@@jamestheotherone742 and what is it if it is true and not shrouded. ?? q
Bertrand Meltz that's great thank you
Ummm, no.
How appropriate to try explaining such a convoluted and hard to understand concept using a convoluted and hard to understand example. Bravo!
That is just what I thought. Analogies are wonderful when they are accurate but simpler, such as liquid flow through pipes in analogy to electric circuits in classical physics.
‘And then I entered into a quantum entanglement with August’
This guy really is so great. The remote lecture he gave on quantum weirdness is the best introduction to the subject anyone could ever do.
I came here trying to understand what Jada meant by Entanglement
I for one am astounded and amazed at these teaching skills- I can´t believe that I- as a somewhat logically challenged and abstract minded and scatterbrained layperson- managed to follow through this lecture and actually felt like I grasped the concepts! Well done!
A lot of the confusion is due to a tiny omission: the same coin in the same box always produces the same animal throughout the thought experiment. This isn't intuitive in the realms of symbolic logic. (I don't think the "NB" solves much, since even it doesn't explicitly state that that output will always be the same if the coin and the box in question are the same.)
you saved my brain, thanks!
Saved my brain too. Thanks Ryan.
Before the big bang, all the space time, and energy and mass that we observe today was crushed in a tiny quantum state. So doesn't this mean that entire space is entangled ?
have not got a clue and doubt that the person to answer your question is going to see or get entangled with your ? q
Good point. They WERE entangled, but breaking the entanglement is really easy.
Other forces affecting the particles (which are largely photons or electrons) is really easy when other particles and/or forces act on individual ones.
Remember, if something affects one particle, there is no "spooky action" on the other particle.
May be both, after all it is quantum J
@@ajit_edu They have done calculations on the likelihood, and with inflation, etc the chances of any original particles being entangled is virtually zero.
@@ajit_edu to the 21Century reply is I get that it is a quantum i not j
As commenter 'allmhuran'
pointed out, the rather offhandedly included line, "NB - these are simple, unconnected mechanical boxes with one given output (animal) per input (coin)" was the single thing that had to be understood (and should've been explained) to make this analogy sensical.
Thank you Phil. I also didn’t understand the example in the initial lecture, so I found this and now understand it.
This is a fault with me not you. If my brain was a bit faster I would have understood it in the first place.
QM is one of the most fascinating disciplines I have ever ventured into.
am still slightly confused ; just means i was paying attention. most coherent, concise explanation delivered in a very pleasurable voice. thank you, truly, for making and then sharing this video with us. let us watch and be nourished
First of all Thank You so much for taking your time and explaining most of the misunderstood parts but.. the last 6 mins of the video was again not to point it was just facts with no proof and also you forgot to explain why it is 85percentage and the idea or the rules which made it 100 percentage .
Thank you
I see it as a plug for a very likely Great Book, I think we are in a real world where more money is paid to a CEO of a minor company than any Nobel from Demark. have fun q
Not quite sure if quantum mechanics broke any laws of physic but I do know it broke my brain.
Don't worry he just doing remap.
Can someone explain this to me. IF Bob puts in a two-euro coin then his outcome will be dependent on what Alice puts in her box. If she puts in a one-euro coin it will produce rabbits, but if she puts in a two-dollar coin it will produce a rabbit & a dog. So Bob's output in this case is dependant on Alice's input and that means the boxes will already have to communicate the inputs to be able to accurately produce the output that satisfies the conditions. I think I'm missing the point
Great talk. And I like the final point a lot. Quantum mechanics is a window into a deeper theory, one where either time or space is emergent. And this 85% limitation may be a clue about what lies beyond it.
There is no such thing as time. It's a human invention based on the rotational period of the Earth. Psychological time is something we have developed related to our ability to store information in our memories but it too is an illusion represented as past and future. The only real state is here and now.
Einstein was wrong when he claimed time can dilate. The inventor of the atomic clock, Louis Essen, claimed Einstein did not understand measurement. He also claimed relativity theory developed by Einstein is not even a theory, but a collection of thought experiments. Einstein arbitrarily added a multiplier to time in equations like s = vt to make it s = kvt, with no proof of that condition. it means not only time can change but distance too, as velocity increases toward the speed of light.
@@jasoncassidy492 You wrongly present your views on the subject of time as facts. There is no scientific consensus on this.
@@arctic_haze ...these are not my views, they are fact. Time was invented by humans based on the period of rotation of the Earth. A period is not defined on time until someone supplies unit, like seconds.
If you can find a phenomenon called time independent of the rotation of the Earth, please post it. Meantime, please consider why we have two forms of time, solar time and sidereal time. One is based on the exact period of rotation of the Earth from noon to noon and the other is based on the period of rotation wrt the stars. That's because the Earth moves a considerable distance around the Sun during a day, therefore one day is longer than the other.
Then you might consider why time has an analog in the distance traveled by a point on the Equator. Time can also be expressed in minutes and seconds (arc length) and not in seconds of time. Therefore time can be a distance as well.
I have discussed this with physicists. Some agree with me and the others become frustrated when they cannot find a time independent of the Earth's rotation. There are sure it is there but they cannot point to it.
@Jason Cassidy I already firgot what your views are. But you can easily measure time without using the Earth rotation. Look how the second is defined.
You should explain this 85% !
basically, the way the experiment is set up, you solve the appropriate quantum mechanics (QM) equations and the 85% comes out naturally. the 75% predicted by hidden variables (HV) is a purely logical approach.
the conflicting predictions come from this logical approach vs the QM equations. there are even more rigorous tests of HV vs QM out there, where HV predicts 0% but QM predicts 100%... QM always wins
Yes, see below. It is called the Tsirelson bound, and arises simply from the way Bell correlations are set up: en.wikipedia.org/wiki/Tsirelson%27s_bound
@@9erik1 No. The 85% is from the error factor in the observations. Not actual reality. If you could observe 100%, then you could observe all state variables without influence and QP waveform collapses to a fixed value. It drops out of QM into plain ol' vector mechanics. No more hocus pocus.
@@jamestheotherone742 nah what I'm saying by the 100% thing is that there are certain bell experiment setups where HV never permits a certain result, whereas QM ONLY permits that result
@Enter the Bragn’ What kind of conspiracy garbage are you trying to push down our throats here?
Quantum is the word that some day Scientists would equate with Cosmic Intelligence. We are waiting for that day to come. Thank you for your interesting talk Dr. Phillip Ball.
At 9.14 it is very confusing. Why do you automatically show rabbits appearing for Bob in Alice’s 2 pound column? By your rules a 2 pound from Alice and a 1 pound from Bob could give two dogs, or two rabbits. Not clear to me even after several rewinds of your explanation.
"Quantum nonlocality" are just words describing a phenomenon that is still spooky.
I've studied Special Relativity since I was 15, some 59 years ago, and found it to be logical, but to this day even with an M.S. in Physics, I find quantum mechanics, at least the way it is interpreted today, to be odd (spooky, if you like). The difference is that Special Relativity does not have the random unpredictable nature of QM. Even though it works, QM still leaves me with an unsettled feeling.
@@wayneyadams I think that's probably because you think humans (smart ones) should be able to understand everything in our universe. Reading Kant's Critique of Pure Reason made me understand that our available logical concepts need not be, and probably aren't, all the logical concepts there are. So until we evolve into higher beings, we are stuck.
@@robertbrandywine The point of my comment was that QM flies in the face of reason. It's a concept that seems like it can't be true and yet all experimental evidence seems to indicate it is.
I agree that our puny little evolved ape brains probably are not at the point where we can truly understand the universe around us.
@@robertbrandywine say what lol
To all making comments about the lecturer: this is the Philip Ball, the author of a phenomenal book Critical Mass: How One Thing Leads to Another. This mind blowing book is a must read for anyone even remotely interested in science and how this world really works.
I lost it as soon as he mentioned rule 2 & rule 3.
iSoloMusician yeah I’m not gonna lie i barely grasped his whole demonstration because of rule 2 and 3.
The subject is scientific therefore you might need to pause the video and work it on your head. I had to come with this array of results by my self to understand it fully. And its actually an easy concept. Its a video after all. Use the advantage it provides such as pause.
Care to explain how you verify that both entangled particles collapse at the same time, when measuring one of them?
If you measure both of them simultaneously they would have collapsed even if they were not entangled.
If you measure one and not the other, how do you know that the other did in fact collapse, and did so at the time of measuring the first one?
If you measure the other one later, you still would not know when the collapse took place.
Exactly how do two photons get ‘entangled’ ? Are they entangled indefinitely? Can a photon get re-intangled with a different photon later ?
TimeTime Only with a legal divorce from the first photon.
It's just the result of certain types of interactions which have certain constraints based on conservation laws, but certain freedom within those parameters.
I don't think particles can change their entanglement. Once they "interact", there are effectively new particles coming out the other side of the interaction.
Rahul Jain ok, so it is kinda like a one way function. With this I think the term ‘entangle’ is misleading. Seems like the term should be changed to be more descriptive and consistent. I feel confident I’m missing something here since scientists agreed upon thus term. I’m still puzzled how two entangled particles can be derived from one source particle unless the two are halved from the one.
@@Elfdogable Particle count is not a conserved quantity. A single photon can split into an electron and a positron, for example. Their wave functions are entangled with each other. One particle's values are based on the values in the other equation and vice versa.
True love is a great example of quantum entanglement where two people can become entangled throughout a lifetime - it's amazing that all we really learn in life is love; what is love, how to love and who we love but nobody educates us about this, not even the Royal Institution!!
Thank you for making this video. It's the best one I've seen on quantum entanglement, and I've seen a lot, trying to wrap my head around it!
I actually see this video as a book pitch and a good one.
Far, FAR from being the best.
@@tabaks For example?
Unfortunately Quantum does not exist and never has for science has proven that the smallest particle in the universe is the proton. Popular Science has even proven that they do not know what an electron is or even light. They have recently proven dark matter and energy does not exist. And the large colliders have proven that given enough energy a proton can be destabilized back into energy. The quantum particles are actually decaying matter back to energy.
That is why these quantum particles only exist for Pico seconds or less! This is actually the time it takes for complete destabilization.
When I think about spin up and spin down, I think of a seesaw, where one end spins about a pivot, so that the opposite end is always the inverse and never the same. So I have a question: If I push up at one end of an arbitrary seesaw, does the other end go down instantly? Is there a delay in the force applied or does this force travel at a finite speed?
What if this pivot approaches an infinitesimal point in size and the seesaw is contructed by an infinitesimally thin line of arbitrary length passing through the pivot - would pushing one end up instantly push the other end down?
If there are two entangled electrons analogous to a pivoted seesaw as above, maybe we should be looking for the pivot?
Your comment made me think of another way you can think of what you said:
If we have a 1 meter stick, the moment I push it from one end, the other end moves immediately. Now, what if we had a 1 km stick, pushing from one end, again affects the other end immediately. Anyone on the other end, would see the stick move immediately as soon as I push or pull it no matter the distance.
For both of you: the force applied travels through the molecules of the object at speed with maximum of that of the EM waves
@@Littleprinceleon Thanks for the answer to the thought experiment. I considered your reply to be accurate, as I was thinking the same when I posted the question way back then. However, since the spin up/ spin down happen instantly, the maximum speed of EM through the material cannot be what is happening as this isn't instantaneous.
I'm thinking of a 'time pivot'. If you consider a pair of anti-matter/ matter particle creation, which happen instantly, and think of the anti-matter as the same particle as the matter particle but travelling backwards in time, then with a similar principle we can also apply this to entangled spin up and spin down as the same particle. When spin is observed with two entangled particles, one can consider the other as the same particle but travelling back in time. Both types of systems are connected with a 'time pivot' and are the same particles but with the 'other' particle travelling back in time. These systems when observed, collapse the wavefunction and give the impression that they are happening 'instantly' and the mechanism travelling faster than light/ EM.
Entangled particles act like c++ pointers :). Different variables pointing to the same memory block.
That is one of the best talks I've seen and heard.
I studied QM at Uni, and his talk gave me a real insight into what I learned through number crunching the equations, but not really being able to form some sort of mental picture about what was going on in that weird QM space. It really is like a "Fairyland of Weirdness", if you study it. It's better than The Adventures of Alice In Wonderland.
Bells Inequality and Bell's Theorem are mind bending concepts to get one's head around.
Oh No, the analogy example was awful, not the e explanation! The author should have come with a different example or best would be to explain simply the real experiment. Trying to explain the same bad analogy again in a longer detailed video is pointless!
Should have come, not should have came. Grammar matters.
Waaaiiittt Alice and Bob analogy?
Excellent explanation of a difficult concept . Perhaps explaining how the " rules " of this scenario apply to the quantum world specifically would wrap things up neatly .
I'm here because Martha said 'Quantum entanglement' while explaining a phenomenon. Had to know what it meant!
My favorite demonstration of entanglement is when you use polarized film to break reality.
Step 1: use polarized film to block ~50% of the light coming from a light source.
Step 2: use a second sheet of the Same kind of film placed perpendicular to the first to block ~100% of the light coming from the light source.
Step 3: use a third piece of the Same polarized film and place it between the other two (currently blocking ~100% of the light) to block ~85% of the light, breaking reality into pieces!
First of all: we have to emphasize that the light gets polarized in some direction from the first filter.
The perpendicularity of the second is regarding it's polarization angle!
Then if you place the third in any angle over the previous two: no light is miraculously renewed from zero light energy.
You have to place the third filter at 45° between the previous two: so you reorient the polarization from the first filter! This new polarization is no longer perpendicular to the second filter (but at 45° angle).
@@Littleprinceleon True, in between, is correct. But it still beggars belief. Not only that, but every filter you add between the first two that isn't aligned with another filter, decreases the effectiveness of the original two. That's still something that blows my tiny mind!
Love the RI videos more than I can say. Keep 'em coming!
I like socks analogy better.
Once you put one of the socks on your left foot, the second one automatically becomes right.
Not to Alice. She can put the other sock on the left foot as well, right?
Socks are non entangleable :P
Definitely something going on when we turn our attention to measuring quantum objects, the double slit experiment also, our thoughts change particle behaviour somehow. Thankyou very much for hashing it out a bit more, it is a mind blowing concept, letting go of preconceptions and being amazed but something that is measurable and real is refreshing.
Just because they are observed as two separate particles isn’t it possible that they are still the one in a sense. No transmission needed , whatever happens to it happens instantly .
Jada Pinkett Smith brought me here.
why? from
where? what did she say? i am
curious
@@hms9520 she was in an entanglement
Great news...
🤣
She’s not bright enough :P
Ok, let's take a thought experiment.
It's a wartime situation where two generals - a 3-star and 1-star - are each in charge of half of an army.
They have a static enemy in front of them and want to attack in a pincer attack from diametrically opposite directions.
They know the enemy has spies listening to all their tactical discussions and communications between the two generals.
They know then the enemy will arrange their defenses to meet the two pincer attacks if they know for certain
the compass direction from which the two attacks will take place.
They will thus prepare for this pincer with half the defenses facing out toward the respective half armies.
If the enemy does not know from where the generals are coming, then it will have to distribute the defenses around the four points of the compass and so be weakened in its defense.
To defeat the spies, the generals decide to make their decision only when they reach the North and South positions and only decide then whether to attack immediately OR suddenly change and attack from the East and West.
They cannot communicate which they are going to do as the spies will intercept the communications.
The generals thus take one entangled particle each and agree that if the 3-star general in the North at the appointed time has a downward spinning particle then he will indeed veer to the East and the 1-star seeing the opposite spin in his particle will veer to the West.
However, if the 3-star general has an entangled particle spinning upwards, then they agree that at the appointed time they immediately attack from the North and South.
The information about the direction of the pincer attacks will take place has therefore passed between them INSTANTLY and without communication - and so fooled the spies.
AND at a speed greater that the speed of light
Where have I got this wrong?
Jim Murray
Familiar with the subject, yet I couldn't follow the talk. Probably an out of context edit?
Maybe it would be a good idea to leave aside Alice, Bob and weird imaginary boxes with strange cooked-up rules, and just state the facts. Nobody needs coins and rabbits here. Those are just adding confusion.
It is not a board game with strange invented rules, it's reality, so start by describing real experiments and their results, and build from there. Only afterwords start discussing what abstract rules might be in place, so we see such experimental results.
RoGeorgeRoGeorge, not very familiar with the subject but I thought the same.
The facts are exactly the statistics produced by B & A's devices.
I can think of something that Alice could put in her box
I am also familiar with the subject. I could not follow the logic and get the same matrix. Did he leave out some bit of information or perhaps I did not understand the rules. Was anyone able to get the same matrix?
Speak for your self this i needs all the help he can get I married a smile/ have fun q
Any entanglement demonstration involving a choice illustrates that the subjective experience of scientist A making a choice, only he knows, violates locality as observed by scientist B, and so the subjective experience of scientist A does not occur in a finite box. Therefore, the human mind cannot be said to be inside a finite box such as the brain, the brain and body, or the body and the local environment regardless of how entanglement works.
if you think of time-space as a grid laid upon a nondimensional void, then entanglement makes sense. "local" is universal in that sense.
Mark, what is a non-dimensional void, and where does it exist
@@robknight9406 a nondimensional void? no time. no space. no matter. just symmetry. virtual nothing balanced out by virtual nothing. our universe came out of a nondimensional void (by means of a random quantum fluctuation) and the time space dimension is still unfolding at the edges. the big bang is still happening.
Mark, what is a non-dimensional void and how can I buy one?
Also, didn't think I could lay a time-space grid on my will to live.
you might get away with it. but, if I was you, i would get someone else to stick their arm in there first and see what happens.
we have taught that while creating entanglement between 2 particles via photon there is conservation of charge which means if a particle have positive charge the other would have negative charge, there is also conservation of spin which means that if one particle have up spin then the other must definitely have down spin .These r the 2 conditions to justify that 2 particles r entangled or not and there is conservation of charge and conservation of spin because to produce the net effect zero as photons don't have charge as well as spin . But the interesting thing here is to note that that there is no conservation of mass between the 2 particles so as to produce the net effect zero as photon mass is zero. My biggest dought which implies that if there is no conservation of charge that particles (not photons) cant be entangled at all. If anyone get some info about this pls inform me in the replies section.
Keep in mind the pencil through the paper worm hole analogy when I say. This is consistent with quantum particles being 4d items while atoms are the 3d effect of those particles. Like a flock vs birds. Since we are made of atoms we can not see the 4d universe.
I predict you may be doing your own paper or thesis or Ted talk if you keep this up,
That is totally NOT what physicists say. You can entangle, disentangle particles (Electrons or Photons) at will with simple benchtop equipment. There are no special "quantum particles"
@@dnomyarnostaw If you think you've made a point on my comment then you best reread it because your statement is in no way relevant to what I was talking about.
@@lucidmoses "quantum particles being 4d items"
..is just nonsense. We are talking Photons and Electrons. Very little else is used as a Quantum particle.
Calling Photons and Electrons "4d" is just woo.
@@dnomyarnostaw ".is just nonsense." Ok, prove it. Or are you just making up assertions. I on the other hand I was careful to summarize and get it right. The least you could do is read what I actually said and argue against that.
Great talk, it makes one think. To me it exposes the issue with only having 4 dimensions, X,Y,Z, and t, and it sort of steers one into the idea of extra dimensions, these being the ones of particle interaction. Say A,B,C, and d are dimensions in which very specific particle properties exist or are modified through, and in this dimensional reality distance and time (or whatever they are) are completely different than XYZt. The abstract idea of extra dimensions can make more sense if we can relate them to things in our own tangible dimensions. It may even be possible to map other dimensions based on these "spooky" particle relationships. I've always had an issue with the idea of extra dimensions, the concept makes no sense, but this talk gets one wondering.
Sometimes you get a lecture that 'clicks ' when the explanation just fits with stuff you have heard before.
I was lucky to experience this from this lecture.
I nearly 'lost it' at the Alice and Bob box analogy,
My big takeaway was confirmation of the 'no spooky action' understanding.
What about the concept of reverse time dependency?
The idea that in normal situations past events influence the future; but, for entanglement somehow future events can influence the past.
Quantum Entanglement is what happens when physicists try to understand quantum theory.
It is called an abomination
It also happens when scientists are desperate for getting new research grants.
there is peculiarity in those particles, they travel at speed of light, what ever is connected between them since the beginning, will remain connected, it's kinda freezes gravity or electromagnetic field that remains constant between them creating one dimension or one piece that collapses when we measure them, because time start to run again, it switches to our dimension, gravity wouldn't allow them to travel at speed of light in the opposite directions if they are connected by gravity, somehow gravity must gain energy as they go apart. It's hard to correlates distance and time, it seems like the particles goes back in time for us as an observer. In other words, if we put two particles in the opposite sides on a balloon, they go apart as the balloon inflates, the act to measure one particle is when we break the balloon, they disconnect immediately, the time is much shorter then it takes to get them apart, the energy releases much faster, space time crashes the whole structure.
One take?!? Cheers
Has anyone considered quantum entanglement uses the gravitational force of the black wholes that connects the entire galaxy and holds the stars of the entire galaxy in place. Creating an entanglement resonance frequency and depending on how you entangle you can get the same or opposite behavior of the two particles 1. By using physical space or 2. by using wholes in the clear sheet like the black whole itself, I called it the black sheet because it is black whole energy, however that implies a light and darkness theory when it's not, it's a clear sheet of energy that is using black whole energy in physical space, or wholes in the clear sheet that the black whole basically is. So one way of quantum entanglement resonance frequency sending you get the same behavior the other you get the opposite behavior. Physical space you get the same behavior, wholes past physical space or the sheet you get the opposite behavior. And you can quantum entangle particles into physical space entanglement or into a whole's in physical space entanglement and use the same black whole energy at the same time not depending on what side of the clear sheet of physical reality and non physical reality you entangle the particles. Or possibly opposite behavior happens if you entangle or code the particles so they are entangled, although one is entangled into physical reality, while the other is entangled into a whole in space, then particles will respond in opposite behavior. And if you encode an entanglement where both electrons entanglements exist in physical reality or both exist in wholes in physical reality they will behave the same.
That was so good...I nearly understood.
I don't think so?
Marek Manini err no.🙁😂
85%?
Here is simple example to understand entanglement.
(Perhaps this may not be the best way).
Suppose two people conversing with each other using a mic. Both are from different country.
1st person: I'm a British but my mic makes my accent seem like a Japanese.
2nd person: But I find your accent to be like an Indian.
1st person: Then perhaps it's because of your speaker.
You can find the co-relation with this between the speaker and mic. And how it effects the actual sound of both.
The explaination is always how entaglement works, that has been stated over and over again.
What always seems to be passed over is why particles gets entagled?
I believe it’s because of energy states. It’s probably easier for two particles nearby each other to be in opposite spins than the same. Opposites attract and similar repels. Opposites are always opposites no matter what so they become linked
"Shared information," "quantum nonlocality," "spooky action at a distance." Asserting that those are different feels like playing with semantics to me. Any way you slice it, the effect is getting from A to B faster than light. Recently there's been the whole ER=EPR thing, equating entanglement to "wormhole like" connectivity between places in spacetime. Well, again that's just another angle to approach the same point from - it implies a "shortcut" from A to B, but that's just tinkering with distance rather than tinkering with time. The end result is the same.
The best explanation I've seen is in Christian Baumgarten's paper, "How To (Un-) Quantum Mechanics." He models reality as an arbitrary collection of state variables that are functions of *time only*, and then makes one assumption: that there exists a single function of those variables that is conserved as the variables change with time. The mathematical analysis that follows shows that three spatial dimensions and most of the modern laws of physics "emerge" as necessary consequences.
Some interactions that occur within this framework depend on those emergent spatial dimensions, and those are limited to a maximum speed (not one put in by hand - that speed limit is also a consequence of the analysis). But other interactions do not depend on the spatial dimensions; they have nothing to do at all with space. So they are not subject to any such speed limit. This is where the "instantaneous" connection between degrees of freedom comes from in Baumgarten's picture of the world. Note that the "time parameter" that these variables depend on is not any particular observers "personal time" - observer time would enter in as another emergent property. The "master time variable" is a single independent thing, and there's no funny business about it. Also note, though, that this master time variable isn't necessarily "accessible" to physical observers residing inside this "reality." It's an attribute of the model only.
Well done , a great lecture and well delivered. I loved the glove analogy , excellent and clever. Makes it clear to a novice.
I've sat down with a pen and paper to try to follow the analogy, but for the life of me I can't. (EDIT: I finally figured it out, see reply comment.) At 9:25 we're told that the combination of rules require a rabbit to emerge from Bob's box whenever Alice puts £2 in her box, but that doesn't seem to be necessarily true. Let's consider the case in which Alice puts £2 and Bob puts £1.
Rule 1 only applies to situations in which Alice puts £1, so it doesn't tell us anything about the case we're considering (as Alice has put £2).
Rule 2 only applies to situations in which both have put £2, so it also doesn't tell us anything about the case we're considering (as Bob has put £1).
Rule 3 states that all other combinations (i.e. (£1/£1), (£1/£2), (£2,£1)) produce either 2 rabbits or 2 dogs. This includes the case we're considering. This rule, however, doesn't state that Bob must get a rabbit. It merely states that both boxes will produce the same thing, whether that be a dog or rabbit.
So, there seems to be no reason to think a rabbit must come out of Bob's box in the case in which Alice puts £2 and Bob puts £1 at 9:25. The same kind of reasoning applies to the case in which they both put £2 and, again, the rules express no reason why a rabbit must come out of Bob's box in that case either.
I've done some digging, and finally found the answer to this problem. Here's how it works:
The first thing we need to observe is there is a less-than-obvious 4th rule (an assumption of locality) in parentheses at the bottom of the list of rules: The boxes have no way of communicating with each other. So, Bob's box must produce an output that accords with all the rules, knowing ONLY what coin was put in by Bob (and without any information about what Alice put into her box).
Now we can return to the case in which Alice puts £2 and Bob puts £1.
According to the 4th rule, Bob's box knows ONLY that he put in £1. As far as Bob's box knows, Alice MAY have put £1 in her box (even though she actually didn't). That means Bob's box knows that it must be in one of the two cases in the top row, but it doesn't know which column. So, Bob's box must now consider what output options are available to it that conform to all the rules REGARDLESS of which of the two situations it might be in.
First, it considers the possibility that Alice put in £2. In this case, the only rule that applies is rule 3: the outputs of the 2 boxes must either be both rabbits or both dogs. In this case, then, Bob's box could produce either a dog OR a rabbit.
Next, Bob's box considers the possibility that Alice may have put in £1. In this case, both rule 1 AND rule 3 would apply. Bob's box knows that, according to rule 1, Alice's box would have produced a rabbit, and, according to rule 3, both boxes must produce the same thing. SO, if this turned out to be the case, Bob's box would have to produce a rabbit.
In both cases Bob's box could produce a rabbit while conforming to the rules, but only in the first case could Bob's box produce a dog. Since Bob's box can't rule out that the first case isn't the actual case, it has to produce a rabbit.
@@andrewj22 Thank you for the explanation!! I spent a long while trying to understand that part before I found your comment
@@Jero_mdz Yay! Someone actually read it!
I saw the talk a while ago and didn't understand the boxes. Now you've told it here again... and it makes no sense what so ever as far as I can discern. Truly, I think that people should just admit that they don't yet understand the quantum scale and how things work there.
I could not follow the logic with the boxes. I could not use their rules and get the same results matrix. the rules seemed fairly simple. I must be missing something. Did anyone reproduce the results matrix from their rules? Please let me know.
and most humans never will understand something that is correct only 85% time in my opinion. have fun q
@@joerock7005 Yes, see my reply to Your other post.
Philip Ball is one of the few people in foundations of physics who recognized the value of the quantum reconstruction program (QRP) early on. He was advocating for that approach as early as 2009 in a RUclips video and shared Dakic and Brukner's information-theoretic reconstruction in a RUclips video on quantum entanglement years ago. Well, it turns out Philip was prescient. Quantum information theorists have now rendered quantum mechanics (QM) a principle theory based on the relativity principle exactly like special relativity (SR), which shows QM is as complete as possible and totally compatible with SR (many believe quantum entanglement renders QM at odds with SR).
With that understanding of QM one can rule out the existence of Popescu-Rohrlich joint probabilities (the PR-box) because they violate conservation per the relativity principle. We explain that in "Why the Tsirelson Bound? Bub’s Question and Fuchs’ Desideratum" Entropy 2019, 21(7), 69. We explain the conservation principle itself in "Answering Mermin’s challenge with conservation per no preferred reference frame" Scientific Reports volume 10, Article number: 15771 (2020). [Those are open access, but I can't provide the links or RUclips will delete this post.] Those articles are a bit technical, but we have it all explained for the "general reader" forthcoming in "Einstein's Entanglement: Bell Inequalities, Relativity, and the Qubit" due out in June 2024 with Oxford UP (see Chapter 8 specifically for the PR-box). Here's a brief summary.
The mystery of quantum entanglement arises because we are looking for a 'causal mechanism' behind its correlations, what Einstein called "constructive efforts." Einstein was faced with a very similar situation concerning constructive accounts of length contraction (and time dilation) to explain the Michelson-Morley experiment. Einstein wrote:
"By and by I despaired of the possibility of discovering the true laws by means of constructive efforts based on known facts. The longer and the more despairingly I tried, the more I came to the conviction that only the discovery of a universal formal principle could lead us to assured results."
That is, he gave up looking for causal mechanisms ("constructive efforts") that would shrink meter sticks and slow down clocks to fool everyone into measuring the same value for the speed of light c, regardless of their relative motions (an empirically discovered fact known as the light postulate). Instead, he said c is a constant of Nature per Maxwell's equations, so the relativity principle -- the laws of physics (including their constants of Nature) are the same in all inertial reference frames -- demands that everyone measure the same value for c, regardless of their relative motions. The Lorentz transformations of SR follow from the light postulate as justified by the relativity principle.
As it turns out, the same opportunity for QM has been provided by quantum information theorists. That is, they have reconstructed QM based on an empirically discovered fact called Information Invariance & Continuity that (in non-information-theoretic terms) means everyone measures the same value for Planck's constant h, regardless of their relative spatial orientations. How does that solve the mystery of quantum entanglement?
Suppose you send a vertical spin up electron to Stern-Gerlach (SG) magnets oriented at 60 deg relative to the vertical. Since spin is a form of angular momentum, classical mechanics says the angular momentum you should measure is (hbar/2)cos(60) = hbar/4 in that direction of SG spatial orientation. But, the SG measurement of electron spin constitutes a measurement of h, so everyone has to get the same +/- hbar/2 for a spin measurement in any SG spatial orientation, which means you can't get what you expect from common sense classical physics. Instead, QM says the measurement of a vertical spin up electron at 60 deg will produce +hbar/2 with a probability of 0.75 and it will produce -hbar/2 with a probability of 0.25, so the average is (hbar/2 + hbar/2 + hbar/2 - hbar/2)/4 = hbar/4. In other words, quantum mechanics says you get the common sense classical result on 'average only' because of the observer-independence of h.
Now suppose Alice and Bob are measuring the spin singlet state (the two spins are anti-aligned when measured in the same direction) and Alice obtains +hbar/2 vertically and Bob measures his particle at 120 deg relative to Alice. Obviously, if Bob had measured vertically he would have obtained -hbar/2, so at 120 deg Alice says he should get hbar/4 per our single particle example. But of course, Bob must measure the same value for h that Alice does, so he can't get the fractional value of h Alice says he should (otherwise, Alice would be in a preferred reference frame). Instead, his outcomes at 120 deg corresponding to Alice's +hbar/2 outcomes vertically average to hbar/4 just like the single particle case. And, of course, the data are symmetric so Bob can partition the results according to -*-his-*- +/- hbar/2 outcomes and show that Alice's results satisfy conservation of spin angular momentum on 'average only'.
In the end, Alice partitions the data per her +/- hbar/2 outcomes and says Bob's results must be averaged to satisfy conservation of spin angular momentum while Bob's partition shows it's Alice's outcomes that must be averaged. This should remind you immediately of an analogous situation in SR. There when Alice and Bob occupy different references frames via relative motion, they partition spacetime events per their own surfaces of simultaneity and show clearly that each other's meter sticks are short and their clocks run slow.
In other words, the mystery of quantum entanglement resides in 'average-only' conservation that results from "no preferred reference frame" (NPRF) giving the observer-independence of h (NPRF + h). And, the mystery of length contraction resides in the relativity of simultaneity that results from "no preferred reference frame" giving the observer-independence of c (NPRF + c). Give up your constructive bias for QM just as is done for SR and physics makes perfect sense. But, the implications for your worldview are profound; you have to accept that physics is most fundamentally about constraints on the 4-dimensional (spatiotemporal) organization of worldtubes per NPRF + c and the distribution of quanta therein per NPRF + h.
I keep thinking that quantum waves and ghosts are related, two sides of the same coin. Like yin and yang. It's the only conclusion that makes sense. Remember that nature uses the least action principle. The universe is inheritance lazy. But there is no reason to disallow a complex life form of very low energy content. QM should predict the existence of ghosts. A ghost is a special kind of wave function that has free will, consciousness, but has to creep between potential energy wells to move around. If you don't see it, then you are being intellectually avoidant.
But the ghost has to be made of something. Specifically, something that interacts with light sometimes. There's no real evidence of ghosts, aside from crackpot supernatural shows and fake videos.
Quantum entanglement is really about the stability of the dynamics of energy. Mathematics can make anything be stable as the same formula with the same data will always deliver the same result, but is nature also that mathematically stable. Two particles interact and develop a dynamic position relative to one another which maintains indefinitely because there is no drag variable to alter that dynamic correlation. The fuzzy part of the quantum entanglement discussion is that it implies that if you observe one entangled particle then the other particle some how freezes to allow the observer time to find the other particle to take a look at it. Correct me if I am wrong but I don’t think that is what happens.
Hi Mr. Philip. I have to say you did such a fantastic job explaining this and it just feels awesome listing to you talk about this topic. I really love physics so much but never gone beyond first year university physics. But I think I have a great real life example of quantum entanglement which I think is really true. I have a little 3 year old daughter. And whenever I think about her I can feel exactly what she is doing. It's totally like the quantum entanglement. When she was a baby every time I would think about her she would start crying. And this was so strong I said to my self I'm going to stop thinking about it. It's hard to explain but in my view entanglement doesn't have a physical "explainable" property to it. But I think a mother/daughter thoughts are entangled. And no matter where she is in the world I can be thinking and knowing exactly what she is doing.
Utter nonsense
I adore the clarity of your explanations.
Schrodinger to Heisenberg “so is the cat dead or alive Werner.” Heisenberg to Schrodinger “well Erwin I’m uncertain about that” 🤣
4:12 why was that spin not determined until Alice measured it and how do we know that exactly? nvm, that's been explained.
I’m starting to love physics man🤩
Xäp 8 RUclips and a biography of Einstein has me on the way back to university.
jordan cox honestly I’m taking an astronomy class which opened my eyes to all of the stem fields and the brilliance of it all. I’m going to be an engineer now
Don't love it once u started loving it u will never ever come out of this physics is addiction
1:15 "What happens when two particles interact. It has to happen." Okay, what particles? Just electrons? photons? Also what does 'interact' mean? (I'm not so much asking the question to get an answer but hoping to help fine tune the explanation. I've been reading this stuff for decades, and some of it is still very difficult to understand. I also know, both as a teacher and a nerd, that refining an explanation is an important aspect of any scientific advance. Example: Einstein's ideas.) And how is spin measured? And if making the observation affects the condition, then if the first measurement has something to do with 'locking in' the spin of the interacting particles, than what happens at the other end (of the experiment. time or distance or both) when the second measurement is taken?
As a teacher I'll come up with something that I'm absolutely sure is elegant, brilliant... and my students shrug. Six months later I'll look at it again, smack my head, and realize I'd left this bit vague or confusing (but then six months or a year after that.... ) I like the glove analogy and the simple chart. And the 85%. thank you
Hold it with the lies. Nobody understands entanglement. The truth is this is what happens. It's spooky, bazaar, can't possibly work that way but it does. That is really our understanding of it.
The truth is that we don't understand what's happening - so there is no way you can say "The truth is this is what happens" The particles are related and have common attributes - but we can't change one and watch the other change accordingly.
stanley Tolle a lie, to me, has intent to mislead, I don't see that here. thanks for your point of view you may be 85% RIGHT EVEN far Right/ q
We think spooky because it is way beyond of our understanding.
Multiple worlds is a explanation.
Who knows.
Clear and concise explanation of a complex phenomena in physics
leaps right over explaining why any connection or hidden variable would be needed (as does every video on this topic).
no explanation of that at all.
if I slice a globe into N/S halves, and send one away, then measure that mine is N, I can know the other is S with no telephone, no hidden info, no secret connection. it's just the other half.
I was waiting for the 85%, then I got entangled.
At 10:48 Alice's box alters its output depending on which coin Bob put in.
At 11:25 Bob's box receives a signal telling it what Alice has put in.
To be consistent, he should have said that Alice's box receives the signal from Bob.
But, if that's the case, and it works under Quantum Entanglement, doesn't that mean you can have FTL communication by deciding what to put in Bob's box to influence Alice's box?
"When we observe it..." Isn't this always the misleading phrase? Shouldn't it be "When there is an interaction..."?
Whether we observe it or not?
Whether we measure it or not?
Why imply that we somehow have to be part of what makes a wave function collapse? When surely they collapse all the time all over the universe far beyond any possible role we might have in them doing so...
I guess because it collapses 'whenever' we observe it. That is what prompts d phrase 'when we observe it'. It is not misleading bcos observer collapses the wave function does not imply that 'sumthing' else doesn't collapse it. It simply implies that 'observer collapses the wave function.'
Ive read that this quantum probabity becomes fixed at any measurement,with or without a conscious observer.
@@drphosferrous yes!! And that maybe completely true. But i guess the thing is a conscious observer collapses it 'for sure'!! And thts wat needs to be looked at too i guess.
@@SanchitShettyTantraYoga i suspect that when "information" is better understood in physics,general relativity will reconcile with these quantum spookularities.
@@drphosferrous yea mayb. But whats interesting is that even though science may not accept the entitative existence of the witnessing principle, it is still interesting to understand that this Universe with all its complexity had the potential to create and also indeed created an observing principle like d human mind wich can observe and understand information. I think a time will come when instead of trying to focus on the small particle which we are trying to understand, humans wud start focusing on tht 'entity' , tht principle wich is actually understanding information!!! I dunno for sure though but sure looks like it wud go that way!
I tried to SHARE this video with my brother but strangely my sister also received it.
😂😂😂
01:45 🤬 telling me I don't need to know about spin/angular momentum.
do you?
Since quantum entanglement is outside of time does that not mean everything in existence is technically still entangled with each other because it was so in the beginning?
RelayV - Nope. We don't know either way.
Reverend Jynxed - depends how you're defining entanglement, nobody wants to do that yet.
Quantum mechanics is very Bohring!
One question regarding the "action at the distance" part and how it's not a thing. It seems that saying that two particles are the same is overlooking the part that they remain connected no matter the distance between them. Meaning that the factor of the distance not mattering seems to be overlooked or, at least, de-emphasized by simply saying they are one object.
Not sure why physics has become so dogmatic in the last 20-30 years. What if Special relativity doesnt apply in all cases? Maybe space/time is an illusion and there is really no separation between the entagled particles!? We assume same rules for Gravity apply everywhere in the Universe with the same constants and then we 'invent' Dark Energy/Matter which we havent been able to detect. Same way we 'invented' the INLATION theory (post Big Bang). I hope the young generation of Physicists/Mathematicians is looking at other options to explain some of these Quantum phenomena without the Dogmatic assumptions.
Well said...It seems it's the physicists who "think outside the box" are the ones who make the breakthroughs. They/we are obviously missing something. (a lot actually. lol). A very complicated universe underneath the veil of apparent solidity : )
@dimi dimitri
sekharpal.wordpress.com/2016/10/16/spaceless-and-timeless-god-and-quantum-entanglement/
Many younger physicists are coming up with new & better theories' unfortunately like any other institute, the mindset & beliefs of established scientists are very hard to change. Often changes only comes about when all the old farts die off.
It's a bit like attaching Alice to Bob with a pole. If Alice pushes her pole, Bob will instantaneously feel the effect. There is no issue with transmission between objects because there is no transmission: Alice, Bob and the Pole are connected and thus, in that moment, the same object. That doesn't resolve the problem of the nature of the pole itself (where is it?), but it does address Einstein's transmission dilemma.
There's a dead cat in one of the boxes.
or possibly both.
I don't see any difference between "two things being one thing" or "spooky action at a distance" or "signals moving faster than the speed of light". It's six of one or a half dozen of the other.
No it's not. You cannot use Quantum Entanglement to send information faster than light. This is because the spin of a particle is random. If you could produce a spin of oyur choice then you could send information faster than light using quantum entanglement
@@EinSofQuester i tot it did not send the info? that's why he said don't listen to that "spooky action" thing... what he meant was, it become the same thing... it doesn't sync via sending info, but it's just the same thing after entanglement.
Awesome teacher and explanation.
I would try framing this as a contradiction: "entangled particles are non-local, while also being local"
Contradictions can often be solved using the 'principle of separation'. e.g. maybe the entangled particles are non-local in the three spatial dimensions, but they are right next to each other (or even fused) in some unobserved dimension?
Nice video! Also, I'm happy to give you a haircut for free!!!
Entanglement is a form of measurement. Bell's Theorem assumed that entanglement excludes quantum tunneling which could conserve the speed of light. The question that is being begged is, "What is the nature of form?" Put in another way: Is there a dimension only accessible to entangled properties in which all points in the universe are equidistant? (i.e. appear as 1 dimensional such as the propagation of electric charge)
I don’t know dude, I got lost at long division in my head.
this experiment reminds me of an x & y chromosomes
Yes i thought the same
So I am trying to come up with simple analogy using spinning coins. Please correct me if I am wrong!
Imagine having two coins on table. Face one Head up and the other Tail up. Now start them spinning at the exactly same time with the same force like beyblade. It is not Head or Tail till its spinning, so to stop them you slam your palm on bot of them at the same time. Now when they are not spinning any-more you can see one is Head and other is Tail (or one Tail other Head depending on moment you stopped them). Makes perfect sense.
Now the interesting part... Spin the coins again, take one coin far away from the other but make sure the coin doesn't fall and keeps spinning. Then slam your palm on only one of the coins and strange thing will happen, the second coin (no matter how far away) will fall at the exactly same time no mater the distance . Also once you stop the coins the entanglement is gone and they are now just ordinary coins.
Am I right?
Forget the earth, the universe is flat!
Yes it is really flat.
A disc.
Some say it's flat. all we know is that it is pear-shaped.
@@karthickpn450
A large disc resting on the backs of four huge elephants which are in turn standing on the back of an enormous turtle.
You know it makes sense.
... which makes the unwrapped tortilla a perfect model of the universe! Get smart - eat tortillas.
10:21 Are the rules intently violated though? Why in the upper right case there is a dog and a rabbit: Bob puts one pound, Alice puts two pounds; any case that doesn't have two 2 pounds results in either double bunny or double dog; so the upper right case it should be that; either double bunny or double dog no?
That’s what was confusing me. I wish that was explained better.
Simply saying that the boxes are no longer separate objects doesn't explain how they communicate from opposite ends of the galaxy in defiance of relativity. Whether they are at opposite ends of the galaxy or across the room from each other, saying they are one object doesn't erase the need for the signals, information, thoughts (whatever you want to call them) to traverse that space.
I seriously understood how this all works yesterday .. after watching this video, I no longer understand it and have thus as a result de-learned it. "Spooky unlearning at a distance" .. appreciate the effort but the math explanation is simply easier to understand.
This is a very good exposition of the CHSH inequality. It may not be obvious to some viewers that Alice is allowed to employ a randomized strategy wherein her £2 randomly draws a dog or rabbit, but they still can’t exceed 75%.
Great video. Quantum entanglement is still a mystery in the sense that we do not yet know why the universe allows such behavior. Quantum non-locality clearly describes the behavior, but does not explain why such behavior, over seemingly endless distances, is even possible. My idea to explain this would be to suggest that spacetime itself is quantized, and as such, spacetime particles exhibit superposition and entanglement as well. In this model, a pair of of entangled electrons is confined within a locus of entangled spacetime particles. The spacetime particles provide the non-locality property that we see for separated electrons - when actually, as far as the electrons are concerned, they are local to each other. That is, they live within the same region of spacetime - which just happens to be entangled. So, there is no violation of special relativity. If we take a moment to consider the implications of entangled spacetime, one idea that pops up is that there are additional spatial and temporal dimensions we cannot directly see - but which allow two entangled electrons to appear to be very far apart, at the time when we measure their spin. However, because they are embedded in entangled spacetime, the electrons are local to each other. It is the entangled spacetime particles in which they reside that gives us the the non-local property that we've been, perhaps incorrectly, attributing to the electrons themselves. It would be great to hear other thoughts and opinions on this topic. Quantized spacetime probably has many more implications that have not yet been explored. But this is one of them. Thanks for posting this video.
One could say that as soon as the two particles became entangled, they decided their configurations, and communicated the same at the time the entanglement was initiated. It's not like the superposition of all states MUST happen for both particles since we are not firing photons to disturb the entanglement, and resolving the configuration of one of them. If it's logical for one of the particles to have an opposite configuration to another at the time of measurement, I don't see why the particles couldn't decide on the configurations at the time of entanglement. A superposition of all states can also be seen as a "particular flavor of state", which is just another way of expressing an unmeasured entangled particle.
Suppose Alice and Bob have one reciprocally-entangled electron each, and Alice flies away to some great distance with hers, then Bob flips the spin of his electron: will Alice's far-away entangled electron also flip spin, at the very same instant? If so, when Alice's electron flips, will it release a low-energy photon? If the answers are both positive, then why should this mechanism NOT form the basis for an instantaneous digital telecoms system with zero signal-propagation delay? Also, if Alice flies away with acceleration serious enough to modify her perception of the rate of time-flow compared to Bob, then what would "instantaneous" mean to Alice and Bob in this Interstellar-like context?