Attentive viewers may have noticed that I broke a promise from the last video to talk about Fourier inversion. I still plan for that to come at some point, perhaps in the context of a video on Laplace transforms, or perhaps after it.
Are you planning on making a video about Laplace Transform? Really love your videos! EDIT: never mind, just saw your answer on reddit, can't wait for the video!
great video sir! could you please make video on z-transform and discrete/digital systems? those are most unintuitive topic of all time for me..but I believe these are most important topic of modern technology.
If you are doing transforms now, consider the Lorentz transform too. You mentioned spacetime here, so it's somewhat related. If you are interested in pursuing that, here's a Minkowski diagram of a light clock in motion, in Desmos. www.desmos.com/calculator/xc1cuqkcdp
Why is it that when I can't understand something, a UA-camr comes out no less than a month later with a beautiful explanation of it. My FBI guy must really care. I love you man.
That's due to quantum mechanics and uncertainties - We're all in 'a WAVE' of dark knowledge (empty head space) - however once certain thoughts are observed deeply enough, a BRIGHt one works out a great PIECE of enlightning information (-:
*@EgonSorensen* QM is mechanics - uncertainty as defined here often has some linkage from Event M to Event ( remote ) ~ few realize Space Lizards actually rule the non-tangible
Great video as always! As a physicist, I just want to point out something that usually bothers me about some phrasings of the uncertainty principle (which you were careful to also do in the last minutes of the video). When people say "you can't know the position and momentum of a particle", you really need to bring the probabilistic interpretation of quantum mechanics to make sense of that. It certainly does not mean that you can't measure both quantities. If you have a certain localized quantum state (with low position uncertainty) and measure its momentum, you will get a definite result in your detector. It is only when you prepare the same localized state and measure its momentum again that you realize the result is now different than before (and repeating this process many many times you'll conclude indeed that the uncertainty of the momentum is large). This has to do with particles in quantum mechanics not being described by its classical state (which is characterized entirely by its position and momentum) but by its wave function. That popular phrasing of the uncertainty principle in a way extrapolates by saying that the particle "has" a position or momentum a priori, which is a little misleading (or at least debatable in the various interpretations of quantum mechanics).
As a physicist I say comments like these need more upvotes for any video talking about the uncertainty principle where this particular point isn't made very clear.
@@michakubisz535 You could say it yes and no. The whole thing again boils down to the argument that Quantum mechanics is not entirely deterministic. So to answer your question, you could say, you can measure it and also predict the "probability" of a particular event happening.
I don't know if you ever read the comments, but I just want you to know that you make the world a better place with your videos. You allow people like me to gain knowledge about subjects that I have always been interested in. In a very tangible sense, the world gets better with each video that you make. I want to sincerely thank you for the effort you put into these and help you have given to so many people. Bravo!
I love these videos. I finally understood the mathematical meaning of the uncertainty principle. And I didn’t comment those other videos, but your Linear Algebra series was excellent. I can’t tell you enough how many times in my life I was multiplying matrices without having any single idea of what it meant. Thank you!!
@@erdemmemisyazici3950 The fact of waves is more fundamental. The idea of not being able to observe electrons because that requires a photon of high energy is true. However, the fact that particles are described by wave functions rather than points in space is what makes the uncertainty principle fundamental regardless of what an observation entails. For example, the uncertainty principle also applies to measuring spin about two different axes. In this case, you don't require a photon to measure this but you can't simultaneously know the spin about two different axes regardless and that is because of the fundamental nature of waves, rather than the act of making a measurement.
Pi is infact related to e" The Natural Logarithms, the Golden Ratio Taylor and Maculin series , Hyperbole, Coding theory, TRIGONOMETRY Exponents , Prime numbers the Quadratic formula,Fermat last theorem, Cantor Ordinal and Cardinal Infinitel numbers
I have 24 credit hours left to get my Bachelors in Electrical engineering, and I can confidently say that I have never heard these concepts explained so clearly. Your past two 20 minute videos have given me more clarity in my field of study than every professor I have ever had combined. Absolutely incredible. #3Blue1Brown>CollegeEducation
@@ilikewaffles3689 having just watched the videos, can confirm, I'm lost in the sense that I wouldn't be able to rephrase the information in my words with any confidence in what I'm talking about. That said, as a lay person I understand the spirit of what he's explaining and would be less likely swayed by "Quantum weirdness mumbo jumbo" pseudoscience peddlers, which I think makes him an excellent science communicator for all levels of background education. I'd love to learn about these Fourier transformations in more depth someday, it's still difficult to clearly understand with just 10-20 minute videos.
I feel like 3b1b does a great job of getting you to that last huge step of truly understanding while school gets you up all the little steps of just grinding out the intuition manually
I remember when someone first told me that the uncertainty principle was due to certain aspects of a particle being Fourier transforms of each other. Totally changed my understanding of it from "impossible to understand" to "reasonable but unexpected".
Great vid so far. Just wanted to raise the point re: quantum uncertainty principle though. It’s not only that the particle’s position/velocity cannot be known (due to length of frequency of waves etc), it’s that when you know one, it doesn’t really have the other in any sense. Ie. it’s not even ‘there’, in the conventional way, to be found.
Pi is infact related to e" The Natural Logarithms, the Golden Ratio Taylor and Maculin series , Hyperbole, Coding theory, TRIGONOMETRY Exponents , Prime numbers the Quadratic formula,Fermat last theorem, Cantor Ordinal and Cardinal Infinitel numbers
Another one of my favorite explanations of the uncertainty principle is taking a picture of a pool table. With a fast shutter speed, you can tell exactly where all the pool balls are, but you can’t tell how fast they’re going. With a slow shutter speed, you can use the motion blur to determine how fast each pool ball is moving, but it’s much harder to say where each ball exactly is.
@@broor that would be two different independent measurements, which wouldn’t actually give you any useful information about both position and velocity at the same time. When you get down to subatomic particles, it actually happens that the act of measuring a particle changes it’s behavior and you can’t have two simultaneous measurements.
@@spyguy318 good answer! But that makes me wonder; why measure at all? If it changes after you measure it anyways. Perhaps, you might answer, to see the outcome of an experiment, but then my idea of measuring the two things separately is still applicable
As an engineering student, even the first seconds of the video blew my mind. I got the gist of the idea (even tho I still don't understand it fully), but the connection between the mathematics and these physics phenomena have never been made for me. This video is truly amazing. I would be so happy if all my professors were only half as good as explaining stuff as you. Truly amazing.
Who says the sequel is never as good as the original. Great follow up to the previous video! I think 50 years from today, educators will point back to you and say- this is how we learned to effectively explain complex ideas. You have really set the bar with your style.
My physics instructors have told me that we know that lumps of mass are basically a big standing wave ... this video makes the concept more tangible. My favorite on your channel so far.
Many years late to this particular party, but as a physicist, I wanted to raise something more about how we often think of the Fourier transform. Often we think of it as something just as fundamental. Mathematically, you can write a function either in the "normal" way, or you can actually write it as the inverse Fourier transform of another function, and you're describing the same function. Because of this, I wouldn't just say that the Fourier transform indicates the frequencies that the original signal correlates to, I would say that the Fourier transform indicates what frequencies the original signal is actually composed of, you actually build your signal from the frequency components. And I would argue that this isn't just a mathematical trick that we get so used to using that it feels like you're building things from frequency components, but rather, that the frequency-domain version of a quantity is equal to its time-domain counterpart: relativity and quantum mechanics both shine a light on this being deeply fundamental, and, with Noether's theorem, connect important quantities (particularly conserved quantities like energy, momentum, and angular momentum) to the Fourier transform and symmetries in spacetime.
You deserve a lot more subscribers. Your videos explain everything so well and are presented beautifully. I hope more people are interested math/physics from watching your videos!
Great video as always. Although a minor correction regarding doppler-range tradeoff for radar: Good range resolution does not require a short-duration pulse, but on a highly localized auto-correlation function, which requires wide bandwidth due to uncertainty principle. Although time duration and bandwidth are inversely related for the wavelet signals you are using, you can use other waveforms that have both long duration (for good doppler resolution) and wide bandwidth (for good range resolution). A typical example would be a repeating set of chirps. But for a given constraint on the waveform’s time-bandwidth product, the range and doppler resolutions are fundamentally limited due to the reasons you described in the video.
Yes! Thanks for sharing. This is more or less the part I referenced “purposefully glossing over”. The original script had something closer to this, but it ended up just being too much too beside the main point the video is shooting for. My hope was to be upfront in the video about things being oversimplified and including a link to where people could learn more in the description would forgive me my sins :)
3Blue1Brown Yeah - I imagine its a constant struggle to balance technical accuracy vs accessibility and straightforwardness on all sorts of details like this. Anyway, keep up the great work!
The way a relationship is established between the Fourier transform and the essence of our reality is gorgeous. Thank you for sharinng this kind of content. The way it is explained and the animations are just brilliant.
I’ve been searching for an intuitive explanation to why the Heisenberg uncertainty principle works for a long time and this is the most beautiful and logically consistent explanation I’ve ever seen. I’ve never had such a high understanding of the uncertainty principle, you made it as simple as you possibly could but no simpler. I think too many of us just accept the facts of quantum mechanics without diving into why they work and the logic and intuition used to build them, why is the hardest question to answer but when it is it leads to a fundamental understanding that births new creative intuitive theories. Thank you for this video.
HOLY .... i was on a 3b1n marathon and was just wondering where Fourier part 2 was ... and thought well, 3b1b hasn't posted in a while ... that means we're gonna get something fresh soon OMGOMGOMG
I went from legitimately hating math after a painful undergrad degree in physics to now... I am blown away, I LOVE IT! Thank you so much for helping my visual mind see the deeper patterns underneath these phenomena. THAT is real learning and it feels so good. Reinvigorated to explore the beautiful and mysterious existence. You are an example of the future of education!
This is beautiful. 4 years after graduating from Electrical Engineering, I have no better place to go to refresh my mind. These videos need more views.
in the vid there was a timeline at 10:38 , on that time line in 1917 it said "Not a lot of physics... because war" and then at 1918 it said, "S'more Rutherford badassery" which meant some more Rutherford (bad ass)-ness since he made i believe this finding about the nucleus: sites.google.com/site/atomicstructure11/history/1918-rutherford
You sir, are AMAZING! Your talent for making complex things understandable is quite remarkable. The animations, the pace, the quality of the ideas being expressed and how they are broken down is pure intellectual joy. I always thought these things were out of my reach but now I understand them much better. Thanks for all of your efforts and you're on my Patreon.
"A particle's momentum is somehow the _sheet music_ describing how it moves through space" that's just a super beautiful way to put it. These videos are exceedingly good and thought provoking, I learn something new and deeper every time I come and re-watch them.
Oh my! I had the energy-time uncertainty principle as my determined question in physics state exam in university this january. The stuff I found and presented to the commission was okay but it would've been so much better with explanation in this video - all suddenly makes sense! Great job man, keep it up, such fundamental links between math and physics always gives so much food for thought.
I really believe the world could be in a profoundly more advanced place if we had more teachers like you. (or more people had acces to those limited set of teachers). Think of all the people that could benefit from these learnings and deep understandings. I studies applied physics in engineering, but your video's on algebra, linear algebra and this on on the *unsharpness* principle really bring my insight in these topics to a whole new level. I feels really wierd to realise how much I did nót grasp things in a fundamental way when I was studying this and at the same time still was able to pass these exams. Makes me wonder how many people finish with a physics degree but do not have the deep insights that you are presenting and teaching in these series of online videos. Glad to be a patreon supporter btw, the world needs more of you. Thank you so much.
Thank you for properly explaining the difference between the uncertainty principle and the non-deterministic interpretation of it. I get really irritated by physicists that treat the two as equivalent or inseparable.
I never heard of this distinction, do you think you could explain the difference? Is this video describing the HUP or the non-deterministic interp.? The NDI just sounds like a more technical description of the HUP.
The difference comes from how you want to view the whole system. It’s a little philosophical. In classical physics, it is often considered that to have complete deterministic knowledge of a system you must precisely know the positions and momenta of all the particles involved. From this perspective it is the HUP that gives non determinism as without the principle we could just use a really localised wave for the position and a really localised wave for momentum and retain determinism. However you could say that a perfectly localised wave is impossible. Also you may want to measure many other quantities, energy, time, temperature, etc. All of these might have some uncertainty relation between them (infact they do). So these are all described by waves and non of the can be perfect spikes at one point. So nondeterminism can really by tracked back to the decision to use waves and define probabilities based on the wave - instead of just the HUP.
Actually it is postulated that single measurements of quantum mechanical systems yield non-deterministic outcomes. The non-deterministic interpretation of the HUP is merely a consequence of this assumption about quantum mechanics itself.
I'm still not following. You explain how classical mechanics and determinism is defined, I get that. Then you say that you need the HUP to dustify the unknowability in this context. This seems like, mathematically, you are simply applying some form of non-deterministic algorithm, one that slides the knowability between two quantities, say time and energy, based on a constant which will include planck's constant. That seems to define both the HUP and this "non-deterministic interpretation". I can't identify a difference! Thank you for taking the time to try and explain this seemingly subtle distinction.
Just discovered this channel tonight...and now I want to retake every damn math and stats course I ever had, from elementary school to grad school, with a vengeance and something to prove. I have never in my life seen these concepts explained so elegantly, and with excellent choices for relating a concept usually seen in one field to an unexpectedly similar concept in another. It feels like all of the facets of math and stats that stayed disparate and unsynthesized in my mind are finally coming together. This is the kind of channel that truly exemplifies what UA-cam, and other similar resources online, can be. Thank you!
This is the most intuitive explanation of the uncertainty principle that I have ever seen. I’ve always found that analogies are one of the best tools to gain better understanding of a topic, and you’ve used them to great effect here.
Wow, I’m blown away by how clever a way it was to explain the concept of confidence growing over time by showing us how the Fourier transforms into a sharper curve, which you’d given us an indication of earlier too. Great way to make the information feel super natural!
This is a particularly spectacular explanation of the HUP. Definitely puts the whole mystical aspect of it into perspective and makes it almost seem reasonable but just unexpected.
Now this video is pure gold! I'm and engineer and not a mathematician, but I've tried endlessly to describe this situation of the trade off between time and uncertainty, which applies to everything. I have tried to explain this so many times on forums, but with only limited success. Your video nails it perfectly. 🙂There is no difference between this quantum uncertainty, than the fact that a completely pure sine wave can only be one which has existed forever, which has also been measured forever too. At the limit there is a trade-off between certainty and how long it has existed and been measured - for everything in the known universe! :-)
Great video, man! However, regarding your pet peeve (15:50)... Keep in mind that the radar analogy (Range ambiguity resolution) isn't completely interchangeable with the Heisenberg uncertainty principle/unsharpness relation. The range ambiguity resolution is a problem with THE RADAR, not the objects being measured. But, in the quantum realm, atomic particles like the electron adhere to the strange DUALITY PRINCIPLE, which you didn't discuss. The particle/wave duality is key to understanding the limits of range ambiguity resolution as an analogy to quantum physics because it introduces this mysterious and strange aspect of quantum mechanics. The problem in measuring the plane lies with the radar. The problem in measuring the electron is the electron itself (we could say it's inherent to nature). P.S.: I'm a physics major, and I was thrilled that you even read De Broglie's seminal paper. Excellent work! Just highlighting something I thought was important and... flew under your radar (ba dum tss).
I'm telling you, physics teachers in college totally abuse the uncertainty principle - above and beyond what should be allowed. I have always wanted to get a mathematician's explanation on this topic because those damn physicists are no good. Thank you so much for this video, Grant!
That's a bit harsh, as every coin has two sides. Consider how many Physicist's have been abused by mathematicians fumbling on about the square roots of minus 1, the natural logarithm and division by zero before being liberated by fellow Physicists with helpful narratives of: cyclic phenomena, how to make a big number a smaller number and the role of a unit in the context of measurement. And spare a thought for the poor Chemists when they encounter semiconductors and grapple with the Fermi level and it expected probability of occupation of 0.5 even though there is no sate to occupy in the band-gap (just like no die has a face value corresponding to the expected value) despite there being a valid statistical tug of war at play. In any case it's a wonderful video. I especially love the videos on linear algebra.
@@cerioscha Yes, there's truth in that. I have always felt like I should have studied at least a few semesters of math before persuing the study of any science (Physics, Chemistry,...,). Especially as chemists, we get hung up on math really often and it personally annoys me, that I get scared just because I see a complicated looking equation.
@@astralchemistry8732 If we can "Keep what we've got by giving it away" [Ian brown] then perhaps we'll take that diagonal step across the prisoner's dilemma payoff matrix and disseminate tactic knowledge with respect and optimism and realise a "Society of minds" [Minsky] where where afford each other a "leg up" to mitigate against "A little learning is indeed a dangerous thing".
@@astralchemistry8732 I used to feel the same way, but frankly, I wasn't particularly interested in abstract algebra, group theory, analysis, etc until I spent entire classes using topics from those subjects in chemistry and physics. 18 year old me would have never guessed how enamored with mathematics I became and forcing me to take those classes beforehand probably would not have gone so well. I do wish I stayed an extra semester to pick up a math minor.
I'm Interested in the DIAGAGNOLIZATION of matrix EIGENVECTORS, and VECTOR using Taylor expansion and DETERMINANT for infinite series and PAULI MATRIX and Clifford Algebra for solving the Schoringer Equation And HEINGBER uncertainty for QUANTUM FIELD PERBUTATION
FINALLY!!! After waiting for a month. I clicked on this video so fast. I forgot to comment when I first clicked because your videos are very interesting
Though I did a course on wavelet transform where this uncertainty principle regarding time-frequency has been taught, I learnt new things. The presentation is simply awesome. Appreciate your hard work.
15:56 I cannot express how relieved I am to hear this, that means many UA-cam channels nowadays don't really understand anything about quantum physics but choose to just confuse the audience by suggesting that "it is what it is" and that the universe is a sneaky sentient being who plays tricks on us. EDIT: I felt like crying at the end of the video, because I felt like I just took a huge step forward in understanding physics more intuitively, that's the beauty of the internet 🥺
In a graduate course in imaging that I taught at The University of Arizona in the 1980’s, I pointed out that the Fourier relationship between a lens diameter and the sharpness of the image is similar to the Heisenberg Uncertainty Principle (HUP) in that a larger lens results in a narrower image blur (a “sharper” image). I did express the opinion that the HUP is not so mysterious or cosmic as it is often interpreted to be.
This is quite unrelated to the video, but could you please do more videos on topics in abstract algebra and number theory. In particular, I'd like to see your take on Galois theory, and other topics in algebraic number theory. Fantastic video by the way!
No it's pile of shit & makes people hate maths. If you want masterclass in pedagogy go to DrPhysicsA. this video by comparison was just a load of gibberish
I believe this video, as well as many others on your channel, are among the greatest works of our time and are incredibly important. What makes this video so special is the depth of the concepts discussed while remaining accessible, intuitive, entertaining, and beautiful. The car blinkers analogy is a really great one. I've seen several videos on the uncertainty principle in search of an intuitive analogy and this one perfectly satisfied that itch. This video is beneficial beyond its entertainment value; The world would be far more enlightened and thus more satifying and beautiful if educators more often took the effort you've taken here. I believe a great majority of people are capable of understanding far more than they believe simply because the explanations provided to them were insufficient. Another element of why this video is so great is the animations are gorgeous and meticulously created; they are such a big part of how the explanations are so easily digestible and understandable. Such a video is inspiring to those of us who highly value education. Thank you for your effort.
This would be fairly easy to do. I already parameterized the x and y coordinates of the sampled points. Why would do you think it would be interesting?
I cannot overstate just how truly brilliant you are with these videos. The best conceptual representation of the uncertainty principle I have ever seen. Ever! Bravo.
It should be noted that the uncertainty principle in modern formulations of quantum mechanics doesn't rely on fourier transform pairs at all. It is instead simply a consequence of non commuting observables and the postulate that single measurements only yield probabilistic outcomes that obey the probability distribution related to the quantum state. In conventional quantum mechanics all observables like position and momentum are represented by complex linear operators (i.e. matrices in most practical cases) with real eigenvalues. So if you're familiar with the linear algebra series of this channel then non-commuting observables can be thought of as pairs of matrices A, B where the product AB is not equal to BA, usually represented as the commutator [A, B] = AB - BA being different to 0. For position x and momentum p the commutator is [x, p] = ih/(2π) for example, with Planck's constant h. The fourier transform in the uncertainty principle then appears as a consequence of this commutation relation.
Also, connecting this further to the linear algebra series (albeit this particular point wasn't covered there) one important consequence of A and B not commuting is that there is no common eigenbasis of A and B. In quantum mechanics the state vector |ψ> (which is almost the wave function) of the physical system becomes the eigenvector correlated to measurement outcome of an observable, which is always an eigenvalue of the measured observable. The position observable X has eigenstates |x> with the eigenvalue equation X |x> = x |x>, where the lower case x is also the eigenvalue (just typical quantum mechanics naming conventions). Same goes for the momentum observable P with P |p> = p |p>. The position wave function ψ(x), which is shown in the video, is the scalar product ψ(x) = , so it is nothing more than a projection of the abstract state of the particle to the position space. Likewise we have ψ(p) = for the momentum wave function. So if the state is in well defined position it is one of the eigenstates of X, meaning |ψ> = |x>. But because X and P are non commuting, i.e. [X, P] = ih/(2π) is not 0, the same |ψ> is not an eigenstate of P and will thus have a range of eigenvalues p as possible measurement outcomes. This is basically the more quantum version of the uncertainty principle which can also be applied to other observables like Spin and Charge.
And btw, to anyone still reading my ramblings about the connection to quantum mechanics: If there was some addendum to the the linear alegbra series including videos about Hilbert spaces, unitary operators, change of basis by means of series expansion and the aforementioned implications of commutation relations, it would be all that is necessary for a starting point for solving actual problems for finite dimensional quantum mechanics problems. If you throw in an introduction to tensor product spaces this would enable one to tackle basic quantum information problems with qubits. After all the mathematics behind quantum mechanics is actually far easier than classical physics, since it only concerns linear algebra and some minor probability theory.
Halberd Rejoyceth first of all, I second this notion. Such an extension to the series would be beautiful. What you said is absolutely true, but the uncertainty principle for Fourier transforms is simply a special instance of what you explained for dual observables, namely if you choose to represent your vector space by the Fourier basis. The commutator builds a vector field on the underlying manifold which, in this case, happens to be constant. I still think it's useful to think about this in Fourier transform terms. It makes it easier to visualize what's going on than having to think about linear algebra on complex manifolds.
Sagar13iffy Try taking a look the book “Quantum Mechanics: A Paradigms Approach” by David H. McIntyre. The book builds up to the concepts mentioned here with not much more than relatively simple linear algebra.
i feel like if we could get all the students that are interested in math watch 3b1b videos instead of going to school and taking some random language class, world would be a significantly better place :>
Well, as you can see, in this case taking a German language class would have helped... it's the math/physics classes that have a problem if a 20 minutes UA-cam video is able to do the job better than hours with a real teacher !
i'm from brazil and my english is not quite good, but, i perfectly understood ever single word that you said, better than most schools here, thanks for make this channel real.
Yes, it's very disheartening that so many Physicists treat the uncertainty principle as proof of fundamental indeterminacy of the universe. Thank you so much for clearing that. Also, your focus on intuition in understanding is a precious trait which the modern education is sometimes lacking. I really love this aspect of your videos.
15:52 explains it perfectly. HUP describes a phenomenon that is true and real. It does not - and was never intended - to make a statement about the fundamental determinacy of reality. Whether the universe is fundamentally indetermined, is an entirely different problem, and until we have even deeper levels of understanding of reality in the future, we can't assume either answer. : )
Mateus Pimentel, it doesn't "have" to be deterministic. It may not be deterministic. We simply cannot know at this point. It would be wrong to assume either way. Keeping an open mind and not jumping to conclusions, is a healthy mindset for the progression of science.
Wonderful video ! Once again 3Blue1Brown you did a great job. Thanks a lot for sharing your knowledge and unique way of explaining thing making use of great graphics technology ! Today I learned several things that I hadn't realized despite being an electronics engineer and having used the Fourier transform for years. I was just about to look for a Laplace transform video on your channel. It's a fascinating topic too. So, yes, absolutely, please make one! As I've mentioned before, I wish I'd had a teacher like you and the technology we have nowadays back when I spend countless hours trying to understand principles like the ones you present. Best regards and thanks again.
I love the visual representation of a particle with multiple vectors and a multiple particcle position with a definite vector, at the end of the video.
It's astonishing to be in the middle of a physics PhD and randomly finding information on FOURIER TRANSFORMS AND QUANTUM MECHANICS that were simply ignored by standard textbooks I've read in years This is extremely interesting ty Mr Pi-man
Excellent video as always but one minor criticism: At 10:52 "...the momentum of any moving particle is going to be proportional to the spacial frequency of that wave" and at 11:25 "Why... should the momentum of those particles... have anything to do with the spacial frequency of that wave?". That phraseology and the general layout (p = hv rather than hv = p) is implying that the momentum of a particle is determined by its spacial frequency, which would be mind-boggling but isn't true: WE can determine the momentum of a particle from its spacial frequency but it is not determined by it. The spacial frequency of the particle is determined by its momentum. Its momentum is determined by the frame of reference and interactions (collisions/forces) just as classical and relativistic physics say. As I say, it's minor but quantum physics abounds with slightly misleading explanations which get latched on to as being the truth. Misunderstandings lead to misinformation and then a million people think that Schrodinger really was saying that the cat is neither alive nor dead instead of proposing that preposterous notion as a refutation of the Copenhagen interpretation (the explanation being that the wave form collapses at the detector inside the box (that is the point of observation) that triggers the poison or not, not when Schrodinger opens the box).
This is my second time coming to this video, learned something new, I guess there'll be a third time after I take a complete introduction course to quantum mechanics.
@@DrDeuteron yes, the real problem starts because we try to associate a wave with mater. And what does it mean for an infinite wave to have finite but precise momentum? What do you think?
Woah, this is probably my favourite video on this channel. The Heisenberg uncertainty principle seems like such a weird and specifically quantum concept, when in reality it applies to every day life. Amazing video 3B1B!
Watched this a second time and it totally makes sense now! If you know where something is, you can't completely know it's velocity. If you know what something's velocity is, you can't really know where it is.
You just summed up my entire childhood in the question of whether the blinkers were in sync. Man, have I spent hours figuring out when they'd meet again.
3B1B you are truly an excellent educator, I don't know how you do it but you take complex topics and package them in a way that is not only are accessible but inspires further thought. Your work is a fine example of teaching mastery. Long may you live and share your skills and enthusiasm. I take my hat of to you.
Stephen Hawking wrote: "Maybe that is our mistake: maybe there are no particle positions and velocities, but only waves. It is just that we try to fit the waves to our preconceived ideas of positions and velocities.The resulting mismatch is the cause of the apparent unpredictability." - A Brief History of Time, ch. 12 - And it's true that quantum mechanics doesn't allow LOCAL hidden variables, but consider instead waves that span the entire universe in a nonlocal spectrum of frequencies. Particles are then simply the result of the sums of those waves, like how the Fourier transform shows that any shape in the spatial (space) domain is the same as a sum of sine waves.
Can anybody could tell how can some one disliked this video and there are 166 of em at this time aug 2018. I'm huge fan of this channel .It is like that if I would get a chance to meet a celebrity Selena, Eminem and this guy I would definitely choose to meet this guy. Please like this comment bcz I want know how are there that feel this same way this would help me improve theory of specificity of human psychological thinking and circumstances that cause them.
Attentive viewers may have noticed that I broke a promise from the last video to talk about Fourier inversion. I still plan for that to come at some point, perhaps in the context of a video on Laplace transforms, or perhaps after it.
3Blue1Brown Thank you
Are you planning on making a video about Laplace Transform? Really love your videos! EDIT: never mind, just saw your answer on reddit, can't wait for the video!
Are you planning to do a multivariable calc series?
great video sir! could you please make video on z-transform and discrete/digital systems? those are most unintuitive topic of all time for me..but I believe these are most important topic of modern technology.
If you are doing transforms now, consider the Lorentz transform too. You mentioned spacetime here, so it's somewhat related. If you are interested in pursuing that, here's a Minkowski diagram of a light clock in motion, in Desmos. www.desmos.com/calculator/xc1cuqkcdp
Why is it that when I can't understand something, a UA-camr comes out no less than a month later with a beautiful explanation of it. My FBI guy must really care. I love you man.
Your welcome,,your microphone was on.
@@Anima_Gacha More like google search etc.
That's due to quantum mechanics and uncertainties - We're all in 'a WAVE' of dark knowledge (empty head space) - however once certain thoughts are observed deeply enough, a BRIGHt one works out a great PIECE of enlightning information (-:
@@EgonSorensen BRIGHT*
*@EgonSorensen*
QM is mechanics - uncertainty as defined here often has some linkage from Event M to Event ( remote ) ~ few realize Space Lizards actually rule the non-tangible
Great video as always! As a physicist, I just want to point out something that usually bothers me about some phrasings of the uncertainty principle (which you were careful to also do in the last minutes of the video). When people say "you can't know the position and momentum of a particle", you really need to bring the probabilistic interpretation of quantum mechanics to make sense of that. It certainly does not mean that you can't measure both quantities. If you have a certain localized quantum state (with low position uncertainty) and measure its momentum, you will get a definite result in your detector. It is only when you prepare the same localized state and measure its momentum again that you realize the result is now different than before (and repeating this process many many times you'll conclude indeed that the uncertainty of the momentum is large). This has to do with particles in quantum mechanics not being described by its classical state (which is characterized entirely by its position and momentum) but by its wave function. That popular phrasing of the uncertainty principle in a way extrapolates by saying that the particle "has" a position or momentum a priori, which is a little misleading (or at least debatable in the various interpretations of quantum mechanics).
As a physicist I say comments like these need more upvotes for any video talking about the uncertainty principle where this particular point isn't made very clear.
as a physics student, i am crying
Does this mean "you can measure but you can't predict"?
@@michakubisz535 You could say it yes and no. The whole thing again boils down to the argument that Quantum mechanics is not entirely deterministic. So to answer your question, you could say, you can measure it and also predict the "probability" of a particular event happening.
@@michakubisz535 You can predict but not with 100% confidence.
I don't know if you ever read the comments, but I just want you to know that you make the world a better place with your videos. You allow people like me to gain knowledge about subjects that I have always been interested in. In a very tangible sense, the world gets better with each video that you make. I want to sincerely thank you for the effort you put into these and help you have given to so many people. Bravo!
You can say that again!
I love these videos. I finally understood the mathematical meaning of the uncertainty principle. And I didn’t comment those other videos, but your Linear Algebra series was excellent. I can’t tell you enough how many times in my life I was multiplying matrices without having any single idea of what it meant. Thank you!!
@@erdemmemisyazici3950 The fact of waves is more fundamental. The idea of not being able to observe electrons because that requires a photon of high energy is true. However, the fact that particles are described by wave functions rather than points in space is what makes the uncertainty principle fundamental regardless of what an observation entails. For example, the uncertainty principle also applies to measuring spin about two different axes. In this case, you don't require a photon to measure this but you can't simultaneously know the spin about two different axes regardless and that is because of the fundamental nature of waves, rather than the act of making a measurement.
@@andonimcleab994 Now that's interesting.
Pi is infact related to e" The Natural Logarithms, the Golden Ratio Taylor and Maculin series , Hyperbole, Coding theory, TRIGONOMETRY Exponents , Prime numbers the Quadratic formula,Fermat last theorem, Cantor Ordinal and Cardinal Infinitel numbers
I have 24 credit hours left to get my Bachelors in Electrical engineering, and I can confidently say that I have never heard these concepts explained so clearly. Your past two 20 minute videos have given me more clarity in my field of study than every professor I have ever had combined. Absolutely incredible. #3Blue1Brown>CollegeEducation
Can say the same. Its so elegant and well thought out. No one puts this much effort anymore.
bro I swear if I knew this guy sooner I'd have passed my digital electronics paper smh
I think these videos are supplemental, not replacements. I'm sure you would be as lost if you only watched these videos.
@@ilikewaffles3689 having just watched the videos, can confirm, I'm lost in the sense that I wouldn't be able to rephrase the information in my words with any confidence in what I'm talking about. That said, as a lay person I understand the spirit of what he's explaining and would be less likely swayed by "Quantum weirdness mumbo jumbo" pseudoscience peddlers, which I think makes him an excellent science communicator for all levels of background education. I'd love to learn about these Fourier transformations in more depth someday, it's still difficult to clearly understand with just 10-20 minute videos.
I feel like 3b1b does a great job of getting you to that last huge step of truly understanding while school gets you up all the little steps of just grinding out the intuition manually
I remember when someone first told me that the uncertainty principle was due to certain aspects of a particle being Fourier transforms of each other. Totally changed my understanding of it from "impossible to understand" to "reasonable but unexpected".
Great vid so far. Just wanted to raise the point re: quantum uncertainty principle though. It’s not only that the particle’s position/velocity cannot be known (due to length of frequency of waves etc), it’s that when you know one, it doesn’t really have the other in any sense. Ie. it’s not even ‘there’, in the conventional way, to be found.
This explanation satisfies me for a single particle. But how does it address the EPR paradox for an entangled pair?
@@tbayley6 Oh, that's easy. www.smbc-comics.com/comic/fossils-3
Pi is infact related to e" The Natural Logarithms, the Golden Ratio Taylor and Maculin series , Hyperbole, Coding theory, TRIGONOMETRY Exponents , Prime numbers the Quadratic formula,Fermat last theorem, Cantor Ordinal and Cardinal Infinitel numbers
Another one of my favorite explanations of the uncertainty principle is taking a picture of a pool table. With a fast shutter speed, you can tell exactly where all the pool balls are, but you can’t tell how fast they’re going. With a slow shutter speed, you can use the motion blur to determine how fast each pool ball is moving, but it’s much harder to say where each ball exactly is.
why not just measure both, separately?
@@broor that would be two different independent measurements, which wouldn’t actually give you any useful information about both position and velocity at the same time. When you get down to subatomic particles, it actually happens that the act of measuring a particle changes it’s behavior and you can’t have two simultaneous measurements.
@@spyguy318 good answer! But that makes me wonder; why measure at all? If it changes after you measure it anyways. Perhaps, you might answer, to see the outcome of an experiment, but then my idea of measuring the two things separately is still applicable
@@spyguy318( and also for every example in the video we can measure separately, but i realise those examples are for teaching the concept)
damn i like this analogy, thank u
You are a shockingly good teacher. I've never seen anything like it.
He has a lovely voice aswell
The graphics help a lot too
Your videos are a blessing for engineering students
As an engineering student, even the first seconds of the video blew my mind. I got the gist of the idea (even tho I still don't understand it fully), but the connection between the mathematics and these physics phenomena have never been made for me. This video is truly amazing. I would be so happy if all my professors were only half as good as explaining stuff as you. Truly amazing.
Who says the sequel is never as good as the original. Great follow up to the previous video! I think 50 years from today, educators will point back to you and say- this is how we learned to effectively explain complex ideas. You have really set the bar with your style.
"A particle momentum is somehow a sheet of music describing how it moves though space." How to do poetry with physics and math. Thanks for the video.
What is a sheet of music? Musical notes on a page?
@@erdemmemisyazici3950 yes, a melody written down on paper
My physics instructors have told me that we know that lumps of mass are basically a big standing wave ... this video makes the concept more tangible. My favorite on your channel so far.
Many years late to this particular party, but as a physicist, I wanted to raise something more about how we often think of the Fourier transform. Often we think of it as something just as fundamental. Mathematically, you can write a function either in the "normal" way, or you can actually write it as the inverse Fourier transform of another function, and you're describing the same function. Because of this, I wouldn't just say that the Fourier transform indicates the frequencies that the original signal correlates to, I would say that the Fourier transform indicates what frequencies the original signal is actually composed of, you actually build your signal from the frequency components. And I would argue that this isn't just a mathematical trick that we get so used to using that it feels like you're building things from frequency components, but rather, that the frequency-domain version of a quantity is equal to its time-domain counterpart: relativity and quantum mechanics both shine a light on this being deeply fundamental, and, with Noether's theorem, connect important quantities (particularly conserved quantities like energy, momentum, and angular momentum) to the Fourier transform and symmetries in spacetime.
You deserve a lot more subscribers. Your videos explain everything so well and are presented beautifully. I hope more people are interested math/physics from watching your videos!
ShockMinerX He’s getting close to one million
751K is pretty good for maths videos. It's a real shame but that's how it goes.
Also 100K views in 19 hours! Not that bad!
HOW ARE YOU SO GOOD AT EXPLAINING THINGS?!
How do you watch 19 minute videos in 2 minutes
Soufian 27 cause i watch all his videos and I already know it’s gonna be good
Soufian 27 but good catch
I thought you were going to tell us that you use a video speedup plugin to speed it up 10 times, and it somehow still makes sense to you. :-)
Extensive revision of a concept throughout the video is the key. This is what almost all school teachers have no regards about. Whatsoever.
Great video as always. Although a minor correction regarding doppler-range tradeoff for radar: Good range resolution does not require a short-duration pulse, but on a highly localized auto-correlation function, which requires wide bandwidth due to uncertainty principle. Although time duration and bandwidth are inversely related for the wavelet signals you are using, you can use other waveforms that have both long duration (for good doppler resolution) and wide bandwidth (for good range resolution). A typical example would be a repeating set of chirps. But for a given constraint on the waveform’s time-bandwidth product, the range and doppler resolutions are fundamentally limited due to the reasons you described in the video.
Yes! Thanks for sharing. This is more or less the part I referenced “purposefully glossing over”. The original script had something closer to this, but it ended up just being too much too beside the main point the video is shooting for. My hope was to be upfront in the video about things being oversimplified and including a link to where people could learn more in the description would forgive me my sins :)
3Blue1Brown Yeah - I imagine its a constant struggle to balance technical accuracy vs accessibility and straightforwardness on all sorts of details like this. Anyway, keep up the great work!
Time to develop some more interactive format where the user converges to technical accuracy by an iterative process ;)
@@halbeard2996 Maybe 3B1B should use glossed over topics as a to-do list of videos.
@@halbeard2996 it already exists. It's called graduate school. :-)
The way a relationship is established between the Fourier transform and the essence of our reality is gorgeous. Thank you for sharinng this kind of content. The way it is explained and the animations are just brilliant.
I’ve been searching for an intuitive explanation to why the Heisenberg uncertainty principle works for a long time and this is the most beautiful and logically consistent explanation I’ve ever seen. I’ve never had such a high understanding of the uncertainty principle, you made it as simple as you possibly could but no simpler. I think too many of us just accept the facts of quantum mechanics without diving into why they work and the logic and intuition used to build them, why is the hardest question to answer but when it is it leads to a fundamental understanding that births new creative intuitive theories. Thank you for this video.
HOLY .... i was on a 3b1n marathon and was just wondering where Fourier part 2 was ... and thought well, 3b1b hasn't posted in a while ... that means we're gonna get something fresh soon OMGOMGOMG
13:48 - Loved the subtweet to minutephysics!! Henry already said in the first video of that series that 3B1B is nagging him to get it done!
Please do more physics oriented videos. I love seeing the mathematical intuition behind it!
I went from legitimately hating math after a painful undergrad degree in physics to now... I am blown away, I LOVE IT! Thank you so much for helping my visual mind see the deeper patterns underneath these phenomena. THAT is real learning and it feels so good. Reinvigorated to explore the beautiful and mysterious existence. You are an example of the future of education!
This is beautiful. 4 years after graduating from Electrical Engineering, I have no better place to go to refresh my mind. These videos need more views.
10:38
"1917: Not a lot of physics... because war"
"1918: S'more Rutherford badassery"
LOL!
Lmao
LOL!
in the vid there was a timeline at 10:38 , on that time line in 1917 it said "Not a lot of physics... because war"
and then at 1918 it said, "S'more Rutherford badassery" which meant some more Rutherford (bad ass)-ness since he made i believe this finding about the nucleus: sites.google.com/site/atomicstructure11/history/1918-rutherford
cool ... I overlooked that one, I guess it was because "the timeline speed" was too high so I wasn't really certain about what was written there.
Rutherford was in New Zealand, and we hadn't received knowledge of the war yet.
You sir, are AMAZING! Your talent for making complex things understandable is quite remarkable. The animations, the pace, the quality of the ideas being expressed and how they are broken down is pure intellectual joy. I always thought these things were out of my reach but now I understand them much better. Thanks for all of your efforts and you're on my Patreon.
"A particle's momentum is somehow the _sheet music_ describing how it moves through space" that's just a super beautiful way to put it. These videos are exceedingly good and thought provoking, I learn something new and deeper every time I come and re-watch them.
Oh my! I had the energy-time uncertainty principle as my determined question in physics state exam in university this january. The stuff I found and presented to the commission was okay but it would've been so much better with explanation in this video - all suddenly makes sense! Great job man, keep it up, such fundamental links between math and physics always gives so much food for thought.
You ask such relevant questions about the topic of concern. And reiterate what it means. For a naturally curious person. This is gold. Thanks a lot.
Damn ! You got the best maths videos of the entire internet !
and that's impressive cuz the internet is BIG
Not quite as big as Graham's Number.
I really believe the world could be in a profoundly more advanced place if we had more teachers like you. (or more people had acces to those limited set of teachers). Think of all the people that could benefit from these learnings and deep understandings.
I studies applied physics in engineering, but your video's on algebra, linear algebra and this on on the *unsharpness* principle really bring my insight in these topics to a whole new level. I feels really wierd to realise how much I did nót grasp things in a fundamental way when I was studying this and at the same time still was able to pass these exams. Makes me wonder how many people finish with a physics degree but do not have the deep insights that you are presenting and teaching in these series of online videos.
Glad to be a patreon supporter btw, the world needs more of you.
Thank you so much.
Thank you for properly explaining the difference between the uncertainty principle and the non-deterministic interpretation of it. I get really irritated by physicists that treat the two as equivalent or inseparable.
I never heard of this distinction, do you think you could explain the difference? Is this video describing the HUP or the non-deterministic interp.? The NDI just sounds like a more technical description of the HUP.
The difference comes from how you want to view the whole system. It’s a little philosophical.
In classical physics, it is often considered that to have complete deterministic knowledge of a system you must precisely know the positions and momenta of all the particles involved. From this perspective it is the HUP that gives non determinism as without the principle we could just use a really localised wave for the position and a really localised wave for momentum and retain determinism.
However you could say that a perfectly localised wave is impossible. Also you may want to measure many other quantities, energy, time, temperature, etc. All of these might have some uncertainty relation between them (infact they do). So these are all described by waves and non of the can be perfect spikes at one point. So nondeterminism can really by tracked back to the decision to use waves and define probabilities based on the wave - instead of just the HUP.
Actually it is postulated that single measurements of quantum mechanical systems yield non-deterministic outcomes. The non-deterministic interpretation of the HUP is merely a consequence of this assumption about quantum mechanics itself.
Can't relate
I'm still not following. You explain how classical mechanics and determinism is defined, I get that. Then you say that you need the HUP to dustify the unknowability in this context. This seems like, mathematically, you are simply applying some form of non-deterministic algorithm, one that slides the knowability between two quantities, say time and energy, based on a constant which will include planck's constant. That seems to define both the HUP and this "non-deterministic interpretation". I can't identify a difference!
Thank you for taking the time to try and explain this seemingly subtle distinction.
Just discovered this channel tonight...and now I want to retake every damn math and stats course I ever had, from elementary school to grad school, with a vengeance and something to prove. I have never in my life seen these concepts explained so elegantly, and with excellent choices for relating a concept usually seen in one field to an unexpectedly similar concept in another. It feels like all of the facets of math and stats that stayed disparate and unsynthesized in my mind are finally coming together. This is the kind of channel that truly exemplifies what UA-cam, and other similar resources online, can be. Thank you!
Welcome to 3B1B.
This is the most intuitive explanation of the uncertainty principle that I have ever seen. I’ve always found that analogies are one of the best tools to gain better understanding of a topic, and you’ve used them to great effect here.
Wow, I’m blown away by how clever a way it was to explain the concept of confidence growing over time by showing us how the Fourier transforms into a sharper curve, which you’d given us an indication of earlier too. Great way to make the information feel super natural!
I love how 3b1b is sponsored with job openings. That's really cool :D
*_3Blue1Brown new video notification_*
Me: What a great time to be alive ! (crying with joy)
This is a particularly spectacular explanation of the HUP. Definitely puts the whole mystical aspect of it into perspective and makes it almost seem reasonable but just unexpected.
Nah that’s two minute papers notification
Is that Pauli I see?
@@sharpieman2035 I was looking for a comment like yours lol 😂
This is the best channel to understand what your lecturer does not know how to explain.
Now this video is pure gold! I'm and engineer and not a mathematician, but I've tried endlessly to describe this situation of the trade off between time and uncertainty, which applies to everything. I have tried to explain this so many times on forums, but with only limited success. Your video nails it perfectly. 🙂There is no difference between this quantum uncertainty, than the fact that a completely pure sine wave can only be one which has existed forever, which has also been measured forever too. At the limit there is a trade-off between certainty and how long it has existed and been measured - for everything in the known universe! :-)
Great video, man! However, regarding your pet peeve (15:50)... Keep in mind that the radar analogy (Range ambiguity resolution) isn't completely interchangeable with the Heisenberg uncertainty principle/unsharpness relation. The range ambiguity resolution is a problem with THE RADAR, not the objects being measured.
But, in the quantum realm, atomic particles like the electron adhere to the strange DUALITY PRINCIPLE, which you didn't discuss. The particle/wave duality is key to understanding the limits of range ambiguity resolution as an analogy to quantum physics because it introduces this mysterious and strange aspect of quantum mechanics. The problem in measuring the plane lies with the radar. The problem in measuring the electron is the electron itself (we could say it's inherent to nature).
P.S.: I'm a physics major, and I was thrilled that you even read De Broglie's seminal paper. Excellent work! Just highlighting something I thought was important and... flew under your radar (ba dum tss).
Your comment is very informative
@@userhandle-l thanks!
I'm telling you, physics teachers in college totally abuse the uncertainty principle - above and beyond what should be allowed.
I have always wanted to get a mathematician's explanation on this topic because those damn physicists are no good.
Thank you so much for this video, Grant!
That's a bit harsh, as every coin has two sides. Consider how many Physicist's have been abused by mathematicians fumbling on about the square roots of minus 1, the natural logarithm and division by zero before being liberated by fellow Physicists with helpful narratives of: cyclic phenomena, how to make a big number a smaller number and the role of a unit in the context of measurement. And spare a thought for the poor Chemists when they encounter semiconductors and grapple with the Fermi level and it expected probability of occupation of 0.5 even though there is no sate to occupy in the band-gap (just like no die has a face value corresponding to the expected value) despite there being a valid statistical tug of war at play. In any case it's a wonderful video. I especially love the videos on linear algebra.
@@cerioscha Yes, there's truth in that. I have always felt like I should have studied at least a few semesters of math before persuing the study of any science (Physics, Chemistry,...,). Especially as chemists, we get hung up on math really often and it personally annoys me, that I get scared just because I see a complicated looking equation.
@@astralchemistry8732 If we can "Keep what we've got by giving it away" [Ian brown] then perhaps we'll take that diagonal step across the prisoner's dilemma payoff matrix and disseminate tactic knowledge with respect and optimism and realise a "Society of minds" [Minsky] where where afford each other a "leg up" to mitigate against "A little learning is indeed a dangerous thing".
@@astralchemistry8732 I used to feel the same way, but frankly, I wasn't particularly interested in abstract algebra, group theory, analysis, etc until I spent entire classes using topics from those subjects in chemistry and physics. 18 year old me would have never guessed how enamored with mathematics I became and forcing me to take those classes beforehand probably would not have gone so well. I do wish I stayed an extra semester to pick up a math minor.
I'm Interested in the DIAGAGNOLIZATION of matrix EIGENVECTORS, and VECTOR using Taylor expansion and DETERMINANT for infinite series and PAULI MATRIX and Clifford Algebra for solving the Schoringer Equation And HEINGBER uncertainty for QUANTUM FIELD PERBUTATION
FINALLY!!! After waiting for a month. I clicked on this video so fast. I forgot to comment when I first clicked because your videos are very interesting
Intuitive Learning same I saw video that I didn't see so I insta clicked
no such thing as forgx or not, can do anyxnmw
What do you mean forgot to comment? You clearly made a comment.
shrdlu I was early and forgot to comment as soon as I clicked because of the video but later I did commented :)
Rocknrolladube lol 😂😂😂
Though I did a course on wavelet transform where this uncertainty principle regarding time-frequency has been taught, I learnt new things.
The presentation is simply awesome.
Appreciate your hard work.
15:56 I cannot express how relieved I am to hear this, that means many UA-cam channels nowadays don't really understand anything about quantum physics but choose to just confuse the audience by suggesting that "it is what it is" and that the universe is a sneaky sentient being who plays tricks on us.
EDIT: I felt like crying at the end of the video, because I felt like I just took a huge step forward in understanding physics more intuitively, that's the beauty of the internet 🥺
In a graduate course in imaging that I taught at The University of Arizona in the 1980’s, I pointed out that the Fourier relationship between a lens diameter and the sharpness of the image is similar to the Heisenberg Uncertainty Principle (HUP) in that a larger lens results in a narrower image blur (a “sharper” image). I did express the opinion that the HUP is not so mysterious or cosmic as it is often interpreted to be.
16:35
Love your description HUP
Finally ... a “no magic” explanation!!!
This is quite unrelated to the video, but could you please do more videos on topics in abstract algebra and number theory. In particular, I'd like to see your take on Galois theory, and other topics in algebraic number theory. Fantastic video by the way!
This is the kind of channel that gets people excited about math. Really a masterclass in pedagogy.
No it's pile of shit & makes people hate maths. If you want masterclass in pedagogy go to DrPhysicsA. this video by comparison was just a load of gibberish
dude that makes so much sense now. none ever talks about why this is but I love that you can bring these abstract ideas into real world examples
I believe this video, as well as many others on your channel, are among the greatest works of our time and are incredibly important.
What makes this video so special is the depth of the concepts discussed while remaining accessible, intuitive, entertaining, and beautiful.
The car blinkers analogy is a really great one. I've seen several videos on the uncertainty principle in search of an intuitive analogy and this one perfectly satisfied that itch.
This video is beneficial beyond its entertainment value; The world would be far more enlightened and thus more satifying and beautiful if educators more often took the effort you've taken here. I believe a great majority of people are capable of understanding far more than they believe simply because the explanations provided to them were insufficient.
Another element of why this video is so great is the animations are gorgeous and meticulously created; they are such a big part of how the explanations are so easily digestible and understandable.
Such a video is inspiring to those of us who highly value education. Thank you for your effort.
Updated Demo with P5js. jbracey2004.github.io/Examples/Excercise00_WindingFunction.html Still Work in progress
Well done sir! I have been experimenting with this idea as well. Here's my work ggbm.at/SbDrHq4k .
Bob Tivnan It would be interesting to see what the position vs time graph would look like with that pi creature
This would be fairly easy to do. I already parameterized the x and y coordinates of the sampled points. Why would do you think it would be interesting?
Bob Tivnan well, to see some 2d figure represented by a waveform; though, there may not actually be such a thing
+Jason Bracey Its just like the video +Bob Tivnan but if you do position vs time then it is always 2 or 3 places at once
I simply love your videos!
Best channel by far in this format (:
I cannot overstate just how truly brilliant you are with these videos. The best conceptual representation of the uncertainty principle I have ever seen. Ever! Bravo.
The best video that I have seen on youtube.....connecting wave mechanics to uncertainty principle in such a simple and beautiful manner.
It should be noted that the uncertainty principle in modern formulations of quantum mechanics doesn't rely on fourier transform pairs at all. It is instead simply a consequence of non commuting observables and the postulate that single measurements only yield probabilistic outcomes that obey the probability distribution related to the quantum state. In conventional quantum mechanics all observables like position and momentum are represented by complex linear operators (i.e. matrices in most practical cases) with real eigenvalues. So if you're familiar with the linear algebra series of this channel then non-commuting observables can be thought of as pairs of matrices A, B where the product AB is not equal to BA, usually represented as the commutator [A, B] = AB - BA being different to 0. For position x and momentum p the commutator is [x, p] = ih/(2π) for example, with Planck's constant h. The fourier transform in the uncertainty principle then appears as a consequence of this commutation relation.
Also, connecting this further to the linear algebra series (albeit this particular point wasn't covered there) one important consequence of A and B not commuting is that there is no common eigenbasis of A and B. In quantum mechanics the state vector |ψ> (which is almost the wave function) of the physical system becomes the eigenvector correlated to measurement outcome of an observable, which is always an eigenvalue of the measured observable. The position observable X has eigenstates |x> with the eigenvalue equation X |x> = x |x>, where the lower case x is also the eigenvalue (just typical quantum mechanics naming conventions). Same goes for the momentum observable P with P |p> = p |p>. The position wave function ψ(x), which is shown in the video, is the scalar product ψ(x) = , so it is nothing more than a projection of the abstract state of the particle to the position space. Likewise we have ψ(p) = for the momentum wave function. So if the state is in well defined position it is one of the eigenstates of X, meaning |ψ> = |x>. But because X and P are non commuting, i.e. [X, P] = ih/(2π) is not 0, the same |ψ> is not an eigenstate of P and will thus have a range of eigenvalues p as possible measurement outcomes. This is basically the more quantum version of the uncertainty principle which can also be applied to other observables like Spin and Charge.
And btw, to anyone still reading my ramblings about the connection to quantum mechanics: If there was some addendum to the the linear alegbra series including videos about Hilbert spaces, unitary operators, change of basis by means of series expansion and the aforementioned implications of commutation relations, it would be all that is necessary for a starting point for solving actual problems for finite dimensional quantum mechanics problems. If you throw in an introduction to tensor product spaces this would enable one to tackle basic quantum information problems with qubits. After all the mathematics behind quantum mechanics is actually far easier than classical physics, since it only concerns linear algebra and some minor probability theory.
I wish so bad that I could understand you.. :'(
Halberd Rejoyceth first of all, I second this notion. Such an extension to the series would be beautiful.
What you said is absolutely true, but the uncertainty principle for Fourier transforms is simply a special instance of what you explained for dual observables, namely if you choose to represent your vector space by the Fourier basis. The commutator builds a vector field on the underlying manifold which, in this case, happens to be constant. I still think it's useful to think about this in Fourier transform terms. It makes it easier to visualize what's going on than having to think about linear algebra on complex manifolds.
Sagar13iffy Try taking a look the book “Quantum Mechanics: A Paradigms Approach” by David H. McIntyre. The book builds up to the concepts mentioned here with not much more than relatively simple linear algebra.
This is easily one of the most underrated channels on youtube. I would like to thank and congratulate you for your quality content!!
i feel like if we could get all the students that are interested in math watch 3b1b videos instead of going to school and taking some random language class, world would be a significantly better place :>
Well, as you can see, in this case taking a German language class would have helped... it's the math/physics classes that have a problem if a 20 minutes UA-cam video is able to do the job better than hours with a real teacher !
i'm from brazil and my english is not quite good, but, i perfectly understood ever single word that you said, better than most schools here, thanks for make this channel real.
I am really enjoying how your videos and minutephysics’ videos are touching upon each other.
Yes, it's very disheartening that so many Physicists treat the uncertainty principle as proof of fundamental indeterminacy of the universe. Thank you so much for clearing that.
Also, your focus on intuition in understanding is a precious trait which the modern education is sometimes lacking. I really love this aspect of your videos.
What's wrong about that?
15:52 explains it perfectly.
HUP describes a phenomenon that is true and real. It does not - and was never intended - to make a statement about the fundamental determinacy of reality.
Whether the universe is fundamentally indetermined,
is an entirely different problem, and until we have even deeper levels of understanding of reality in the future, we can't assume either answer. : )
Why people thinks that the universe 'HAS' to be deterministic? lol what
Alexander LI, I agree completely!
Mateus Pimentel, it doesn't "have" to be deterministic. It may not be deterministic. We simply cannot know at this point. It would be wrong to assume either way. Keeping an open mind and not jumping to conclusions, is a healthy mindset for the progression of science.
14:09 this is the first time I have understood relativity (i think). Out of phase example is great. I have not seen it anywhere else.
"As if a particle's momentum is somehow the sheet music describing how it moves through space". So profound 🤯
I found this channel just yesterday and it's the best thing I found on internet till date.
No words to describe how beautiful it is. Thank you so much for sharing.
Wonderful video ! Once again 3Blue1Brown you did a great job. Thanks a lot for sharing your knowledge and unique way of explaining thing making use of great graphics technology ! Today I learned several things that I hadn't realized despite being an electronics engineer and having used the Fourier transform for years. I was just about to look for a Laplace transform video on your channel. It's a fascinating topic too. So, yes, absolutely, please make one! As I've mentioned before, I wish I'd had a teacher like you and the technology we have nowadays back when I spend countless hours trying to understand principles like the ones you present. Best regards and thanks again.
I LITERALLY jumped out of excitement when I saw this video in my sub box
I love the visual representation of a particle with multiple vectors and a multiple particcle position with a definite vector, at the end of the video.
This video is quite an eye-opener. Never thought of or even heard of Fourier transform explained like this in my 4 years in EE
It's astonishing to be in the middle of a physics PhD and randomly finding information on FOURIER TRANSFORMS AND QUANTUM MECHANICS that were simply ignored by standard textbooks I've read in years
This is extremely interesting ty Mr Pi-man
OMG Heisenbergs princible boggled my Mind for so long! I had allready accepted that i'd never understand it but now there is new hope! Thanks a lot!
Excellent video as always but one minor criticism:
At 10:52 "...the momentum of any moving particle is going to be proportional to the spacial frequency of that wave" and at 11:25 "Why... should the momentum of those particles... have anything to do with the spacial frequency of that wave?".
That phraseology and the general layout (p = hv rather than hv = p) is implying that the momentum of a particle is determined by its spacial frequency, which would be mind-boggling but isn't true: WE can determine the momentum of a particle from its spacial frequency but it is not determined by it. The spacial frequency of the particle is determined by its momentum. Its momentum is determined by the frame of reference and interactions (collisions/forces) just as classical and relativistic physics say.
As I say, it's minor but quantum physics abounds with slightly misleading explanations which get latched on to as being the truth. Misunderstandings lead to misinformation and then a million people think that Schrodinger really was saying that the cat is neither alive nor dead instead of proposing that preposterous notion as a refutation of the Copenhagen interpretation (the explanation being that the wave form collapses at the detector inside the box (that is the point of observation) that triggers the poison or not, not when Schrodinger opens the box).
This is my second time coming to this video, learned something new, I guess there'll be a third time after I take a complete introduction course to quantum mechanics.
Thanks!
Dude, if there were teachers like you all around, then the whole world would've been thriving even faster. Love you for your creative insights.
one video is equivalent to what i've learnt in my 4 years degree.
Then you must not have learnt anything.
Binit Shakya i doubt it was literal
Maybe he had a 4 year liberal arts degree or something
in other words, this video is not a piece of cake to understand.
Or in other words, what's being shown is a beautifully simplified view of more complex math and physics.
2:00 Perfect pitch people: "You dare underestimate me mortal?"
Sir, you are a GOD at making hard concepts approachable!
I am a second year BSc Physics student
Thank you sir for posting this videos.
It seriously helps developing intuition
Wow! That's the best description of the Heisenberg Uncertainty Principle on UA-cam. Thank you very much! 🙏
Hats off sir🎩!
From your videos , I'm getting real meaning of maths and science.
keep it up..
Thank you for your videos, and I enjoyed every single one of them. Can't wait until you hit 1 million subs
Actually, the relation between position and momentum is exactly the "Fourier transform relationship".
then real question, then, is not the HUP, but de Broglie....why is p ~ k? (and it's k that's exact, p is scaled by hbar).
@@DrDeuteron yes, the real problem starts because we try to associate a wave with mater. And what does it mean for an infinite wave to have finite but precise momentum? What do you think?
Woah, this is probably my favourite video on this channel. The Heisenberg uncertainty principle seems like such a weird and specifically quantum concept, when in reality it applies to every day life. Amazing video 3B1B!
Watched this a second time and it totally makes sense now!
If you know where something is, you can't completely know it's velocity.
If you know what something's velocity is, you can't really know where it is.
Essentially Quantum mechanics is the equivalent of "You can't have your cake and eat it too"
I learned more in the first 10 seconds than I have learned from reading about HUP for ten years.
Nice vid. Also nice Falcon Heavy easter egg
Is there a channel like this for biology & chemistry?! ... learning intuitively is the way to go, Good job 3Blue1Brown :)
You just summed up my entire childhood in the question of whether the blinkers were in sync. Man, have I spent hours figuring out when they'd meet again.
watching one video like this equals 4 years in engineering college, Thank you for your efforts.
1:28 shouldn’t the height of the peak in the bottom chart (*/frequency) increase, as the time increases?
you are right. it should. it's a probability density function so it should integrate to one, hence as it narrows in width the peak should increase.
that was an elegant explanation! and visually beautiful.
"A particle's momentum is the sheet music describing how it moves through space" - 3B1B
3B1B you are truly an excellent educator, I don't know how you do it but you take complex topics and package them in a way that is not only are accessible but inspires further thought. Your work is a fine example of teaching mastery. Long may you live and share your skills and enthusiasm. I take my hat of to you.
Stephen Hawking wrote: "Maybe that is our mistake: maybe there are no particle positions and velocities, but only waves. It is just that we try to fit the waves to our preconceived ideas of positions and velocities.The resulting mismatch is the cause of the apparent unpredictability." - A Brief History of Time, ch. 12 - And it's true that quantum mechanics doesn't allow LOCAL hidden variables, but consider instead waves that span the entire universe in a nonlocal spectrum of frequencies. Particles are then simply the result of the sums of those waves, like how the Fourier transform shows that any shape in the spatial (space) domain is the same as a sum of sine waves.
I clicked in this video so quickly...
I clicked with momentum
Clicked it so fast that my location while clicking it could not be determined with a reasonable degree of accuracy
I always watch the videos in my feed in order. I like that SFIA always posts early :)
Can anybody could tell how can some one disliked this video and there are 166 of em at this time aug 2018. I'm huge fan of this channel .It is like that if I would get a chance to meet a celebrity Selena, Eminem and this guy I would definitely choose to meet this guy. Please like this comment bcz I want know how are there that feel this same way this would help me improve theory of specificity of human psychological thinking and circumstances that cause them.
Thanks a lot for all the work you put into this!
My guy, you have the smoothest voice and a good enough understanding to explain this to others. Thank you!
your gift for mathematical explanations is quite shocking. The world needs more of these multiple-vewpoint explanations.