Part 2 is up: ruclips.net/video/tHfGucHtLqo/видео.htmlsi=s-mr2l79q46_QkJ6 If you want to do this experiment at home, you can! It's very simple. All you'll need is: - a weak red laser pointer (the type in cat toys are generally safe) - polarizing film or polarizing filter. If you have polaroid glasses or certain camera ND filters you may already have this. Otherwise it's available on amazon - the half waveplate (the plastic thing) is this one: www.edmundoptics.co.uk/f/polymer-retarder-film/14827/ (λ/2 Retarder Film (WP280)) - You don't need calcite, but if you want to play with it, you can find it on etsy usually. Look for a sample that's exceptionally clear. - BBO: I spent a while messaging people online and had trouble tracking it down :'( I'll settle for KDP or even KTP.
Thank you for this. Finally "superposition" sounds less like magical gobbledigook nonsense, and more like something normal when explained in a realistic and logical way. If I understand correctly, this means one component can be a 1 while another component can be a 0, and saying one thing can be both 1 and 0 is just a very poor and confusing way to describe it, especially to lay-people.
@@brothermine2292 The actual Alice Liddell wasn't blonde, but Disney made her into that. I've seen her in a variety of different colours of dress, so there's no reason she can't wear a lovely red one to match Mithuna!
@@rosuav : Thanks for that info. But my reply was about the Alice who used to frequent this channel. Her hair was always blonde and she always wore the same blue dress. Eve will be needed if this channel produces videos about cryptography, in which Alice & Bob want to communicate without any Evesdropping.
That is pure brilliance! I‘m studying form my QC finals at MIT and procrastinated with this video, and this is such an amazing viewpoint! Really excited about part 2!
@@LookingGlassUniverse meditation is a quantum process, ancient practice of being so conscious of present moment that u lost normal consciousness of body and mind and enter into pure state of void without any though but still super conscious and its blissful, scientist should try this even the Schrödinger read book like Upanishad to understand the ancient wisdom.
Q: "Why does light move slower in different mediums?" A: "I have no idea, stop asking me." That gave me a good chuckle xD. But thank you for the answer
I love it when i find someone who is so smart that they can explain super complex physics to a normal guy like me. You are inspirational for us nerds who never went to uni.
"I hate doing experiments." Spoken like a true theorist. Do you know the story of Pauli and Bohr? Whenever Pauli would visit Bohr in Copenhagen, as soon as he crossed the border into Denmark, all of the experiments in Bohr's lab would suddenly break. Somehow I missed your last two videos. Sorry. I'm glad you finally found a happy electron. Usually they are so sad. I also like your new version of Alice. At any rate, I'm glad you're posting again.
20:38 "I definitely would not have come up with it" you just described 99% of my programming career lol. I did not expect this video to go into such depth, but I was not unhappy about it. This subject is honestly borderline impenetrable, I still don't have any idea wtf is happening with light polarization, I understand how it's illustrated but... well... waves are 3D in reality, pictures are 2D, does not compute in brain. And then you have the whole circular polarization thing which is just .. wat?
Glad this got recommended! I took a "NAND to Tetris" style class in undergrad, there's real magic to making a computer. Your generation is lucky enough to be making tabletop quantum computers for cheap!
I had long ago wondered how plastic polarizers were made. I knew the polymers were alligned, but I didn't know how. It just occured to me that they are aligned by a process similar to making stringed mozzarella chease. Cheese is made up of chains of amino acids that make up the proteins in cheese and start off randomly aligned. Then when you pull a blob of chease in one direction, all the proteins sticking tother and slide past each other are pulled into a common alignment in the direction of the pull. With plastic, a sheet can be made by pressing a blob in one direction. That reduces the polymers degree of freedom to random alignments in two dimentions of a sheet rather than in 3 dimentions of a blobe. Now pulling on a sheet in one direction in the plane of the sheet will mostly align the polymers down to one dimention of freedome. But to achieve better polymer alignment, the long sheet can be cut many times into squares that get stacked with their polymers aligned and gently heated as they are pressed and pulled again to improve the polymers' alignment.
The description of waves operating in 3D and thus made of vectors is the critical piece that's been missing for me since high-school! I finally get it! Thanks so much, such a great explanation!
i can't describe how much this channel blows my mind. i was screaming at the screen at 19:05 BTW to see our old friends Alice and the negative electron come back animated was really fun, and truly a good strategy too to fortify your "brand" since it is so recognizable for us long time viewers
Why does everything has to be "a brand" nowadays? Even personality is "a brand" for anyone. Sick society. She deserves it, so she should deserve it, that's it, for me.
This is the first Looking Glass Universe video and my first real-step into learning about quantum computing. Having graduated HS in 1961 and only completing a few college courses I need things explained very simply and this lady does that in a very entertaining way. I'm looking forward to watching more Looking Glass Universe videos.
The video is about making a homemade quantum computer. Here are the timestamps for the different sections: 0:00-1:05: Introduction and motivation for making a homemade quantum computer. 1:05-3:20: Explanation of what a qubit is and how it works. 3:20-5:35: Explanation of how light can be used to create qubits. 5:35-8:20: Demonstration of how to filter light to create a specific qubit state. 8:20-11:00: Explanation of how a calcite crystal can be used to perform computations on qubits. 11:00-13:20: Demonstration of how to use a thin calcite crystal to perform a simple computation. 13:20-15:00: Discussion of the limitations of the homemade quantum computer. 15:00-17:00: Conclusion and plans for future videos. I hope this summary is helpful! made by "google bird ai"
I cannot WAIT for the next video! This was honestly the BEST explanation I've seen for me to understand the basics of quantum computing while keeping me engaged throughout and I love how you simplified it to it's core components separately! Really excited to see it in practice! (I do wish that the personification of the wave of light was a bit less terrifying and uncanny though...)
I, for one, thought it was quite charming, the bit when she seems surprised and says it's gonna be in the next video. This did lighten-up my day, somewhat. 🙂
Whatch out for those lasers. Or rather not. I mean, just don't point them at your eyes, they can have quite devastating effects. I'm sure, you're well aware but just thought I'd mention it since some people might want to reproduce your (super cool) experiment! Love your videos, btw!
Gosh, this is the only person in the world who can possibly explain this extremely simple system to us, are you joking me. Literal professors can’t even come close to this good of an explanation without using words that mean nothing to me. Like, cool they can be both 1 and 0 but like has physically (the particle is vibrating in two directions both horizontal and vertical is all they had to say but noooooo), no professor I’ve seen on RUclips has ever attempted to explain it as well you have.
Super cool! 😀Love your enthusiasm, curiosity and ability to simplify what seems complex. Looking forward to your follow-up. I suspect you are about to cook up more interesting insights 💡
I just rewatched your video on your PhD, and from my limited understanding, the computing advantage is that the qubit unlike a digital logic gate has the entire complex plane available which is a massively greater information space; in order to simulate that in it's entirety you need to numerically approximate a hilbert space. The computational difficulty and advantage lies in that rather than using logic gates to do complex matrix calculations, the bits have an intrinsic complex space available. The information is distributed rather than being localized as in digital memory.
You’re my inspiration, I am about to start my undergraduate degree next year and whatever I achieve further down, i owe it to you, since you restored my confidence in the subject despite failing in it multiple times. Thank you and wonderful work!
At some point in this video I accidentally finally understood circularly polarised light while you were moving the fuzzy sticks around. It’s the horizontal and vertical components being out of phase… Thank you so much - 10 years of professors waving their hands and saying “oh and there’s circular polarisation light but don’t think about that” and a RUclips video makes it click for me
Thank you for laying out your thought process this video made me IMMENSELY curious about circularly polarized light and no one ever explains it well (and I'm... not a physics knowledge haver) so I had to check in the comments before I went on a research adventure and that makes SO much sense!
They say that you can tell how much a person understands a topic by how well they can explain it. This is Feynman level of explanation- it is that good! Seems like this is like multiplying two real numbers in spherical space ( at least in part) when compared to multiplying integers in spherical or non Euclidean spherical spaces. Trying to understand where the extra degrees of freedom, sum is a worth more more than the parts comes from, but is not able to be emulated in non quantum space, could definitely use your explanation capabilities to inform the rest of us! Thanks for the great video!
Banger video! I never really thought about how simple some core concepts of quantum computing can be conceptually, and how immediately accessible it is to demonstrate them!
As the output would be every possible path of the game at the same time you would have to tilt your head(the sunglasses) just right to see the Best final score. But that takes away all the fun of playing doesn't it?
The way you explained this cleared up SO many questions I've had about this stuff. It's been just too complicated and you perfectly simplified it for my style of thinking! Thank you so much
The quality and brilliant simplicity of this video is amazing. If only schools could be this engaging and educational. They have a lot of catching up to do. Awesome, as usual!
I'm so so proud of you. Been following you for what feels like a decade now. The production value of your videos just gets better and better. So lovely to see your work coming together.
If you just combine two lasers you won't get superposition, you'll get a "mixed" state of two. So you need to somehow sync the lasers or split the ray of one.
@@LookingGlassUniverse imaging having two sines whose period will be almost the same. Their phase difference will slowly drift one relative to the other unpredictably, as their phases are not constrained by anything. So every time you get a different superposition. To get the proper superposition you need to sync the phases.
very interesting, hope to see more of this (maybe more useful quantum computers homemade) in the future. I believe one of the reasons why light "slows down" in a medium is not that light slows down, but it gets diffracted thus changing the distance it has to travel to leave the medium, making it look like it slowed down.
This is wonderful. I just found your channel for the first time. I love the time spent carefully explaining every aspect along the way. You're an awesome educator. Liked and subscribed.
Such a great video!! Loved your breakdown of vector math and that the basic fundamentals of quantum computing is basically just pythagoras and trigonometry... its just the same math as complex numbers. Your descriptions are great at teaching complex stuff with just the right amount of complex and 'simple' (ie ignoring really complex stuff that isn't required to understand the fundamental concepts, but still going deep enough to allow us to learn new stuff). Also you show how this 'mysterious' superposition idea that people can get caught up on is around us everywhere, we just dont use the term 'superposition'... ie the 'sound' or 'timbre' of an instrument, that allows us to identify a piano vs a trombone is because of the combination of frequencies that make up each note... we hear one 'sound' or one 'note' but that sound is make up of a load of different, but related frequencies all mushes together. Suddenly concepts that people understand are also the same concepts as superposition just named differently (like the math is fairly similar as well - an Fourier Analysis shows the component frequencies just as it would on your light source, other Analysis could show the different phases of those frequency components, as it would with the light etc).
Amazing video, and the other video about speed of light in water was a great primer. It's awesome to get such a good explanation from someone that actually studied quantum physics without getting bogged down in jargon. Thanks and looking forward to the next episode
Awesome video, thanks! Especially the explanation of the polarization filters was great. Which reminded me of a question I had for a long time that maybe you can help me understand. One famous "popular science" experiment is to take two 90degree polarization filters to block all light. Then insert a 45 degree filter in the middle and some light makes it through. The misleading conclusion is "and isn't it amazing, adding another filter should block even more light, but surprise, surprise, some light makes it through now". I always felt that this conclusion is dishonest. The polarization filter only blocks 100% if offset by 90 degrees. It's like smashing head on against a wall. Adding filters in the middle rotates the light step by step, making sure there's always a non-zero component in the new direction. Then it's totally not surprising that some of the rotated light passes through the last filter, right? It's like adding angled walls so I bounce off at an angle, changing direction each time, before I hit the last wall at an angle instead of smashing it heads on. In my understanding, the "mystery" in this experiment only comes from a deliberately misleading explanation of what the filters do. With the correct explanation, there's nothing surprising going on, is it? Do I see this right or am I missing something?
I think you’re right, but somehow I still find that experiment mind bending. The explanation is straightforward, and all you need is classical EM theory, yet I find it hard to accept. Like, if you add lots of filters slightly rotated, the end light can be 90 degrees from the original light. But how is this possible. Light is a force, how can a force have a component perpendicular? It’s very weird, even though it makes sense. Thinking of the polariser as a filter might be the problem..
@@LookingGlassUniverse After watching 3Blue1Brown's videos (who pointed me here), I'm pretty sure your explanation of which polarisation makes it through the filter is the wrong way round - if I understand it's the electron oscillation that propagates the light, not absorbing the light, and where the electron is restricted from oscillating in a certain direction, the photon is absorbed then re-emitted in a random direction (same as shining a light on any opaque surface. Edit: not sure this point about opaque surfaces is correct - I think it's actually that all opaque surfaces either absorb and re-emit photons as blackbody radiation, or reflect photons with the same wavelength, in a random direction (or exact incident direction in case of mirrors). But I standby by the point that the photons that do get through the material do so via electron oscillation (otherwise, 3Blue1Brown's videos are confusing and/or wrong)) And I think that explains how light gets through multiple filters - if vertically polarised light enters the filter which is at 45 degrees, the electrons still oscillate in the filter (just not as strongly as if completely aligned), and the light gets propagated in the direction of that oscillation, i.e. at 45 degrees, so the polarization is effectively twisted.
@@LookingGlassUniverse My understanding (probably flawed, since it's been almost 40 years since I studied this stuff) is that the light coming out of the second filter is a mixture of vertical and horizontal. I think it's a lot like measuring spin.
@@LookingGlassUniverse if @laurencedarby9042 has it right (and I seem to remember the same from the 3Blue1Brown video, but it has been a few weeks since I have seen it) then thinking about the polarizer as a filter really is the wrong model that causes the confusion. It's more of a directional re-emitter. And with the re-emission, the turning of the polarization shouldn't be a surprise or mysterious effect at all, right? Case A: Light comes at 0 degrees, polarizer at 90 degrees, light excerts zero force in the polarizer 90 deg direction. No light emitted, polarizer dark. Case B: Light comes at 0 degrees, polarizer at 45 degrees. Light pushing left-right will push the electrons along the 45 degree polymer "rails", but less strong (50%). New photons get emitted on the other side of the polarizer, but aligned with the 45 degree "rail", because that's what's emitting it. Light looks like it turned but lost intensity. Case C: Add the third 90 degree polarizer back in and do the same again and you get 25% light out. If this model is accurate, this seems straight forward to understand intuitively without misrepresenting the experiment as showing weird quantum-effects as many publications do.
I just took a class on Quantum computing. Its theory was very elegant(I tend to skew towards complexity theory), but watching this practical video was pretty inspiring. The most beautiful theories have the simplest experiments.
This is the first video I have seen that actually explains what happens inside the quantum computer instead of simply saying that qubits are in the state of 1 and 0 at the same time
Mithuna, I was a fan of your whiteboard videos from almost a decade ago. Didn't realize you had returned to making videos until this got recommended to me (I thought I was a subscriber, who knows what the algorithm is up to) and it's such a breath of fresh air. I'm so glad to see the same clarity of thought in this new format.
I don't know for certain if this is why, so taken with a grain of salt, my intuitive sense for why light travels slower in a medium is because it bounces around from from molecule to molecule which slightly increases the distance traveled before reaching the destination of the measurement. I imagine it kind of like having several small mirrors spaced out and aligned on top and bottom in front of a laser to create a zig zag pattern that ultimately reflects the laser onto a wall to be measured. You can shine the laser straight onto the wall, or you can tilt it to zig zag across the mirrors onto the same spot. The wall is the same distance from the laser in both cases, but the laser light travels a further distance to reach the destination when it bounces off of the mirrors. It's like traveling in a vertical line, and then adding in some horizontal distance. I haven't really looked into how it works, so I could be wrong, but this is how I imagine it. After all, a vacuum is just empty space, and a medium is space + matter. Since fundamental particles don't really occupy the same space at the same time, I imagine putting a bunch of particles in the way of the light would alter its course a bit.
Loved this video! Can't wait for the next one. I especially love that it allowed us to see some of the "figuring it out" part. Being from the South in the US, I laughed out loud at "the hell?".
Fantastic :) Now I can understand why a cubit can have two states at the same time. It has a little bit more of the up and a little bit less of the right. And when the computation is right, we can have the result we wanted in the first place. So you “set” the answer. And then try to find the right question :)
Thanks for the video. This experiment looks more like a demonstration on the classical interpretation on polarization of light than a quantum computer.
Wow I can't believe it's been years since I joined this channel! It's been a great ride and I've gone from a guy doing a bachelor's in physics with no clue about his future to a PhD student in quantum gravity with no clue about his future XD. It's been real fun!❤
I've always loved your videos and missed them a lot. you have a unique way to present matters visually very clearly while also making it fun, bizarre and a bit magical.
Thanks to your incredible videos and style of explanation, my understanding of quantum mechanics/computing keeps getting better and clearer! My niece too loves your videos and wants to build a quantum computer one day! We both hope you keep these videos coming! :)
8:07 So if I understand it correctly, it's basically like working with vectors. The horizontal one is along the x-axis, the vertical along the y-axis and by changing the magnitude (strength) of these vectors, you can change the direction in b/w these two states, of the resulting vector that is
This is awesome, I'm so glad you put this together from things pretty much anyone can get and also explained it! Visual computation is so interesting to watch... idk why lol.
excellent video! thanks for this fascinating perspective. I don't have the time or money to get a PHD right now so this is helping me come up with ideas for building the one I have wanted to for about 20 years.
I hate doing (physical) experiments also. I just login to some place, and do it online. (I'm now too lazy.) A few years ago, I used IBMQ. (I think it's called IBM Quantum, now.). All in Python. Introduced me to different gates, such as Hadamard and CNOT gate, the concepts of superposition and entanglement. Can also just do it with linear algebra (matrices), though for only very simple cases. But enough to demonstrate the concepts. This is assuming a STEM background, but without knowledge of quantum computing. (This maybe a little bit more than your intended target audience. But it's another way to get an introduction.)
Probably a very silly question, but here goes. In the video about light slowing down in water it was explained that the moving electrons re-emit the light, but in the explanation of the polarity filter here it is suggested that the electrons just absorb all the light.
I love your videos! They gave some of the key tools for me to study proper quantum mechanics courses. Your explanations are also very straightforward and fact-based. :)
Its got nothing to do with the video but I have some calcite myself when I got curious about its ability to aid in navigation: By placing a dot on one side and looking through the other on an overcast day you can find the sun by making the dots you see the same brightness. (By who and to what degree it was used in this way in history is a little contentious, but it does work.)
Very nicely explained. Some questions: 1. Laser light passing through a half-wave plate followed by a polarizer is a single qubit quantum computer. Is this a correct description? If yes, what exactly we are computing? 2. Why the light beams of H and V polarization are 'entangled'? 3. If we repeat the same experiment using radio waves, is it still a quantum computer?
6:23 seems like an excellent time to tell people about the logic RM3, an SMCC, a symmetric monoidal closed category, also the name of my cat Mr. SMC Cat.
It's a bit crazy how divorced physics education is from hands-on experience. It would be nice to play around with the phenomenas we're studying on the blackboard every once in a while.
I would disagree! I’ve done a lot of education and the subject that got the most demonstrations was definitely physics! Especially the broad strokes intro classes. Once you get into the more extreme stuff it’s a little harder to play with the material without really expensive equipment I think.
When the light passes through the polarizer, why do the electron jiggles “absorb” the wave instead of creating their own wave, like the glass electrons in the “does light slow down” video?
Very good video, makes it a lot easier to understand. I do have one complaint, the idea of an electron as a little ball. This, while fine from a mathematical/chemistry perspective is not accurate for what is actually happening. Let's say you have a dam, with the gate open and water spraying out the bottom. The entire stream going down the river is the negative charge (electrons). Where as the funnel inside the dam, the suction, is very localized (proton, positive charge) it is only in one location, it doesnt really move. However one does not exist without the other. The big long stream of electrons does not exist with out their source, the opening inside the dam. Electrons are a unit of measurement, not a little marble. Much like a gallon is a unit of measurement, not a thing.
I can see how rotating the polarizer works at "rotating" the polarization, but it seems like moving the filter closer or farther away would also "rotate" it. I.e., what's the difference between phase angle and polarization angle of an EM wave? BTW, 3BlueAnd1Brown did a very nice video on how glass slows light. Feynman's lectures also has a well written chapter on it. Basically, EM waves jiggle electrons and the jiggled electrons create a delayed wave that adds to the transmitted wave and causes a phase shift that, effectively "slows" the light.
I like these videos. It demonstrates that voyage of discovery in science that is so important for learning science. Note on safety, although I am sure you are using Class 1 laser pointer which are safe without needing protective eyeglasses, people watching this are going to want to repeat the experiments themselves, and if you buy laser pointers from the internet they might say they are Class 1, but in fact be far more powerful. So I think wearing laser protective eye-ware in videos like this would set a good safety example.
I got caught up in stalking your channel to learn more about quantum mechanics/physics/engineering when I’m in a general chemistry class learning about surface tensions… I’d much rather be here.
Fun to imagine. Bonus extra Feynman type guessing a QM 1st of April at Christmas time..? Love the honest presentation of Quantum Computational Logic proving that the design is useless. The Looking Glass Universe analysis is essential to decode the confidence of the Designer, primarily to demonstrate the illusion of separation, as impossible as BBT discrete-ness, and you notice that the Universe is logarithmic condensation modulation in/of instantaneous i-reflection at the Centre of Time Duration Timing, ie purely thermodynamical => mathematical superimposed motion-> Act-uality of relative-timing interference positioning resonance bonding dimensionality. It's not Caterpillar food after all? Allow "Spin" to be the Totality of Singularity-point positioning Conception, of a Looking Glass Universe.., equally useful to imagine. "It's called research" because we don't know what Experiments are for? Serendipity, learning by doing experience and getting a different result is the lottery winner's rationale for gambling. Useless for Quantum Operator Logic. Truth in Labelling? Entanglement entertainment is an experimental success?
Hey, Omg the timing couldnt have been more impeccable, me and my few friends recently a few months back successfully replicated a Bit assignment protocol in a Quantum Optical Laser system, it would be wonderful to talk about it and how you could have used that instead of a BBO or maybe an Axicon, the operator mechanics there is much to complex and has issue with Heralded photon detection. We would be more than happy to discuss and share our protocol if that is something you want to replicate / try out. Cheers
Part 2 is up: ruclips.net/video/tHfGucHtLqo/видео.htmlsi=s-mr2l79q46_QkJ6
If you want to do this experiment at home, you can! It's very simple.
All you'll need is:
- a weak red laser pointer (the type in cat toys are generally safe)
- polarizing film or polarizing filter. If you have polaroid glasses or certain camera ND filters you may already have this. Otherwise it's available on amazon
- the half waveplate (the plastic thing) is this one: www.edmundoptics.co.uk/f/polymer-retarder-film/14827/ (λ/2 Retarder Film (WP280))
- You don't need calcite, but if you want to play with it, you can find it on etsy usually. Look for a sample that's exceptionally clear.
- BBO: I spent a while messaging people online and had trouble tracking it down :'( I'll settle for KDP or even KTP.
Did you really point a laser at your eye?
Got to write a paper on manual quantum computation with 16 qbits.
the trick is analog or mechanical systems are way faster than a transistor.
Thank you for this. Finally "superposition" sounds less like magical gobbledigook nonsense, and more like something normal when explained in a realistic and logical way.
If I understand correctly, this means one component can be a 1 while another component can be a 0, and saying one thing can be both 1 and 0 is just a very poor and confusing way to describe it, especially to lay-people.
You're so wrong
I notice that Alice's animation is getting better and better. Hopefully this will continue
I have an animator, she’s incredible: kathysarpi.com
Wasn't Alice blonde, and always wearing a blue dress? This may be her evil stepsister Eve.
@@brothermine2292 The actual Alice Liddell wasn't blonde, but Disney made her into that. I've seen her in a variety of different colours of dress, so there's no reason she can't wear a lovely red one to match Mithuna!
@@rosuav : Thanks for that info. But my reply was about the Alice who used to frequent this channel. Her hair was always blonde and she always wore the same blue dress. Eve will be needed if this channel produces videos about cryptography, in which Alice & Bob want to communicate without any Evesdropping.
@@brothermine2292Along with Bob who will be wondering what happened to his messages from Alice.
That is pure brilliance! I‘m studying form my QC finals at MIT and procrastinated with this video, and this is such an amazing viewpoint! Really excited about part 2!
Good luck!!
@@LookingGlassUniverse meditation is a quantum process, ancient practice of being so conscious of present moment that u lost normal consciousness of body and mind and enter into pure state of void without any though but still super conscious and its blissful, scientist should try this even the Schrödinger read book like Upanishad to understand the ancient wisdom.
@@rameshdevasi6720 which book?
@@rameshdevasi6720huh came with that thing, this is written long back in India😂
Q: "Why does light move slower in different mediums?"
A: "I have no idea, stop asking me."
That gave me a good chuckle xD. But thank you for the answer
I love it when i find someone who is so smart that they can explain super complex physics to a normal guy like me.
You are inspirational for us nerds who never went to uni.
I really appreciate how you explain complex things so well
"I hate doing experiments."
Spoken like a true theorist. Do you know the story of Pauli and Bohr? Whenever Pauli would visit Bohr in Copenhagen, as soon as he crossed the border into Denmark, all of the experiments in Bohr's lab would suddenly break.
Somehow I missed your last two videos. Sorry.
I'm glad you finally found a happy electron. Usually they are so sad.
I also like your new version of Alice.
At any rate, I'm glad you're posting again.
Oh that's Alice. I thought she race swapped herself.
@@kayakMike1000lol
There will never be a happy electron. Pipe dream. Give up all hope of ever seeing that.
Never Never! show to your audience which may now little about what a laser is, that you check the lasers by looking into them.
I feel like I’m learning about quantum computing in a kindergarten classroom. This is a good thing. I’m understanding everything and loving it
20:38 "I definitely would not have come up with it" you just described 99% of my programming career lol. I did not expect this video to go into such depth, but I was not unhappy about it. This subject is honestly borderline impenetrable, I still don't have any idea wtf is happening with light polarization, I understand how it's illustrated but... well... waves are 3D in reality, pictures are 2D, does not compute in brain. And then you have the whole circular polarization thing which is just .. wat?
"Mom can we have quantum computer at home?"
"We already have quantum computer at home"
Quantum computer at home:
Okay
M'kay.
Valid lol
I worked on a Birefringence Measurement System many years ago. It's awesome to see Birefringence in a real world example!
Thank you for explaining quantum computing so that even kids could understand it. Awesome channel, glad the algorithm found it for me.
Glad this got recommended! I took a "NAND to Tetris" style class in undergrad, there's real magic to making a computer. Your generation is lucky enough to be making tabletop quantum computers for cheap!
I had long ago wondered how plastic polarizers were made. I knew the polymers were alligned, but I didn't know how.
It just occured to me that they are aligned by a process similar to making stringed mozzarella chease. Cheese is made up of chains of amino acids that make up the proteins in cheese and start off randomly aligned. Then when you pull a blob of chease in one direction, all the proteins sticking tother and slide past each other are pulled into a common alignment in the direction of the pull.
With plastic, a sheet can be made by pressing a blob in one direction. That reduces the polymers degree of freedom to random alignments in two dimentions of a sheet rather than in 3 dimentions of a blobe. Now pulling on a sheet in one direction in the plane of the sheet will mostly align the polymers down to one dimention of freedome.
But to achieve better polymer alignment, the long sheet can be cut many times into squares that get stacked with their polymers aligned and gently heated as they are pressed and pulled again to improve the polymers' alignment.
I believe it was 3 blue one brown that made a really good series to teach how light is slowing down in a medium.
The description of waves operating in 3D and thus made of vectors is the critical piece that's been missing for me since high-school! I finally get it! Thanks so much, such a great explanation!
i can't describe how much this channel blows my mind. i was screaming at the screen at 19:05
BTW to see our old friends Alice and the negative electron come back animated was really fun, and truly a good strategy too to fortify your "brand" since it is so recognizable for us long time viewers
Thank you so much for sticking with me❤️
Why does everything has to be "a brand" nowadays? Even personality is "a brand" for anyone. Sick society.
She deserves it, so she should deserve it, that's it, for me.
This is the first Looking Glass Universe video and my first real-step into learning about quantum computing. Having graduated HS in 1961 and only completing a few college courses I need things explained very simply and this lady does that in a very entertaining way. I'm looking forward to watching more Looking Glass Universe videos.
The video is about making a homemade quantum computer. Here are the timestamps for the different sections:
0:00-1:05: Introduction and motivation for making a homemade quantum computer.
1:05-3:20: Explanation of what a qubit is and how it works.
3:20-5:35: Explanation of how light can be used to create qubits.
5:35-8:20: Demonstration of how to filter light to create a specific qubit state.
8:20-11:00: Explanation of how a calcite crystal can be used to perform computations on qubits.
11:00-13:20: Demonstration of how to use a thin calcite crystal to perform a simple computation.
13:20-15:00: Discussion of the limitations of the homemade quantum computer.
15:00-17:00: Conclusion and plans for future videos.
I hope this summary is helpful! made by "google bird ai"
Where's the timestamp for retinal burn?
I cannot WAIT for the next video! This was honestly the BEST explanation I've seen for me to understand the basics of quantum computing while keeping me engaged throughout and I love how you simplified it to it's core components separately! Really excited to see it in practice!
(I do wish that the personification of the wave of light was a bit less terrifying and uncanny though...)
Ahahaha thank you so much!! Sorry for creeping you out with the light caterpillar
The genuine surprise at the end (not being useless after all) is priceless. Thank you! Your excitment is truly entangling 😊
I, for one, thought it was quite charming, the bit when she seems surprised and says it's gonna be in the next video. This did lighten-up my day, somewhat. 🙂
@@jojolafrite90 absolutely, makes me want to buy some lasers 🌟
Whatch out for those lasers. Or rather not. I mean, just don't point them at your eyes, they can have quite devastating effects. I'm sure, you're well aware but just thought I'd mention it since some people might want to reproduce your (super cool) experiment!
Love your videos, btw!
Gosh, this is the only person in the world who can possibly explain this extremely simple system to us, are you joking me. Literal professors can’t even come close to this good of an explanation without using words that mean nothing to me. Like, cool they can be both 1 and 0 but like has physically (the particle is vibrating in two directions both horizontal and vertical is all they had to say but noooooo), no professor I’ve seen on RUclips has ever attempted to explain it as well you have.
Super cool! 😀Love your enthusiasm, curiosity and ability to simplify what seems complex. Looking forward to your follow-up. I suspect you are about to cook up more interesting insights 💡
I just rewatched your video on your PhD, and from my limited understanding, the computing advantage is that the qubit unlike a digital logic gate has the entire complex plane available which is a massively greater information space; in order to simulate that in it's entirety you need to numerically approximate a hilbert space. The computational difficulty and advantage lies in that rather than using logic gates to do complex matrix calculations, the bits have an intrinsic complex space available. The information is distributed rather than being localized as in digital memory.
I just love your videos. they are so fun to watch. please keep doing what you're doing!
You’re my inspiration, I am about to start my undergraduate degree next year and whatever I achieve further down, i owe it to you, since you restored my confidence in the subject despite failing in it multiple times. Thank you and wonderful work!
At some point in this video I accidentally finally understood circularly polarised light while you were moving the fuzzy sticks around. It’s the horizontal and vertical components being out of phase… Thank you so much - 10 years of professors waving their hands and saying “oh and there’s circular polarisation light but don’t think about that” and a RUclips video makes it click for me
Yes! That’s it. I feel bad for cutting it from this video but I’m glad it was clear for you anyway
Thank you for laying out your thought process this video made me IMMENSELY curious about circularly polarized light and no one ever explains it well (and I'm... not a physics knowledge haver) so I had to check in the comments before I went on a research adventure and that makes SO much sense!
They say that you can tell how much a person understands a topic by how well they can explain it. This is Feynman level of explanation- it is that good!
Seems like this is like multiplying two real numbers in spherical space ( at least in part) when compared to multiplying integers in spherical or non Euclidean spherical spaces. Trying to understand where the extra degrees of freedom, sum is a worth more more than the parts comes from, but is not able to be emulated in non quantum space, could definitely use your explanation capabilities to inform the rest of us! Thanks for the great video!
Banger video! I never really thought about how simple some core concepts of quantum computing can be conceptually, and how immediately accessible it is to demonstrate them!
I cant wait for someone to get Doom running on a few lasers and sunglasses next year!
As the output would be every possible path of the game at the same time you would have to tilt your head(the sunglasses) just right to see the Best final score.
But that takes away all the fun of playing doesn't it?
The way you explained this cleared up SO many questions I've had about this stuff. It's been just too complicated and you perfectly simplified it for my style of thinking! Thank you so much
Describing qubits in terms of polarized light is the first explanation of quantum computing that begins to make sense to me. Thanks!
The quality and brilliant simplicity of this video is amazing.
If only schools could be this engaging and educational. They have a lot of catching up to do.
Awesome, as usual!
I'm so so proud of you. Been following you for what feels like a decade now. The production value of your videos just gets better and better. So lovely to see your work coming together.
I've been sort of randomly down a rabbit hole of quantum youtube videos lately and this is by far the best explanations I have seen.
One of the best educational videos I've seen on RUclips's platform. Thank you bath for your work and time!!!
Thank you, young lady. You are shedding "light" on quantum computing :-)
If you just combine two lasers you won't get superposition, you'll get a "mixed" state of two. So you need to somehow sync the lasers or split the ray of one.
No, you do get superposition. If you cross two laser beams for example, you get interference at the intersection
@@LookingGlassUniverse imaging having two sines whose period will be almost the same. Their phase difference will slowly drift one relative to the other unpredictably, as their phases are not constrained by anything. So every time you get a different superposition. To get the proper superposition you need to sync the phases.
very interesting, hope to see more of this (maybe more useful quantum computers homemade) in the future. I believe one of the reasons why light "slows down" in a medium is not that light slows down, but it gets diffracted thus changing the distance it has to travel to leave the medium, making it look like it slowed down.
This is wonderful. I just found your channel for the first time. I love the time spent carefully explaining every aspect along the way. You're an awesome educator. Liked and subscribed.
That poor hapless electron. I'm so glad you are making videos again. Your explanations are some of the best on the entire Youbiverse.
Such a great video!! Loved your breakdown of vector math and that the basic fundamentals of quantum computing is basically just pythagoras and trigonometry... its just the same math as complex numbers.
Your descriptions are great at teaching complex stuff with just the right amount of complex and 'simple' (ie ignoring really complex stuff that isn't required to understand the fundamental concepts, but still going deep enough to allow us to learn new stuff).
Also you show how this 'mysterious' superposition idea that people can get caught up on is around us everywhere, we just dont use the term 'superposition'... ie the 'sound' or 'timbre' of an instrument, that allows us to identify a piano vs a trombone is because of the combination of frequencies that make up each note... we hear one 'sound' or one 'note' but that sound is make up of a load of different, but related frequencies all mushes together. Suddenly concepts that people understand are also the same concepts as superposition just named differently (like the math is fairly similar as well - an Fourier Analysis shows the component frequencies just as it would on your light source, other Analysis could show the different phases of those frequency components, as it would with the light etc).
love this concept. btw i'm clipping where you shined the laser on your face to give my lab instructor a heart attack :d
Please do, it’s a great demo of what not to do
Amazing video, and the other video about speed of light in water was a great primer. It's awesome to get such a good explanation from someone that actually studied quantum physics without getting bogged down in jargon. Thanks and looking forward to the next episode
Awesome video, thanks! Especially the explanation of the polarization filters was great. Which reminded me of a question I had for a long time that maybe you can help me understand. One famous "popular science" experiment is to take two 90degree polarization filters to block all light. Then insert a 45 degree filter in the middle and some light makes it through. The misleading conclusion is "and isn't it amazing, adding another filter should block even more light, but surprise, surprise, some light makes it through now". I always felt that this conclusion is dishonest. The polarization filter only blocks 100% if offset by 90 degrees. It's like smashing head on against a wall. Adding filters in the middle rotates the light step by step, making sure there's always a non-zero component in the new direction. Then it's totally not surprising that some of the rotated light passes through the last filter, right? It's like adding angled walls so I bounce off at an angle, changing direction each time, before I hit the last wall at an angle instead of smashing it heads on. In my understanding, the "mystery" in this experiment only comes from a deliberately misleading explanation of what the filters do. With the correct explanation, there's nothing surprising going on, is it? Do I see this right or am I missing something?
I think you’re right, but somehow I still find that experiment mind bending. The explanation is straightforward, and all you need is classical EM theory, yet I find it hard to accept. Like, if you add lots of filters slightly rotated, the end light can be 90 degrees from the original light. But how is this possible. Light is a force, how can a force have a component perpendicular? It’s very weird, even though it makes sense. Thinking of the polariser as a filter might be the problem..
@@LookingGlassUniverse After watching 3Blue1Brown's videos (who pointed me here), I'm pretty sure your explanation of which polarisation makes it through the filter is the wrong way round - if I understand it's the electron oscillation that propagates the light, not absorbing the light, and where the electron is restricted from oscillating in a certain direction, the photon is absorbed then re-emitted in a random direction (same as shining a light on any opaque surface. Edit: not sure this point about opaque surfaces is correct - I think it's actually that all opaque surfaces either absorb and re-emit photons as blackbody radiation, or reflect photons with the same wavelength, in a random direction (or exact incident direction in case of mirrors). But I standby by the point that the photons that do get through the material do so via electron oscillation (otherwise, 3Blue1Brown's videos are confusing and/or wrong))
And I think that explains how light gets through multiple filters - if vertically polarised light enters the filter which is at 45 degrees, the electrons still oscillate in the filter (just not as strongly as if completely aligned), and the light gets propagated in the direction of that oscillation, i.e. at 45 degrees, so the polarization is effectively twisted.
@@LookingGlassUniverse My understanding (probably flawed, since it's been almost 40 years since I studied this stuff) is that the light coming out of the second filter is a mixture of vertical and horizontal. I think it's a lot like measuring spin.
@@LookingGlassUniverse if @laurencedarby9042 has it right (and I seem to remember the same from the 3Blue1Brown video, but it has been a few weeks since I have seen it) then thinking about the polarizer as a filter really is the wrong model that causes the confusion. It's more of a directional re-emitter. And with the re-emission, the turning of the polarization shouldn't be a surprise or mysterious effect at all, right? Case A: Light comes at 0 degrees, polarizer at 90 degrees, light excerts zero force in the polarizer 90 deg direction. No light emitted, polarizer dark. Case B: Light comes at 0 degrees, polarizer at 45 degrees. Light pushing left-right will push the electrons along the 45 degree polymer "rails", but less strong (50%). New photons get emitted on the other side of the polarizer, but aligned with the 45 degree "rail", because that's what's emitting it. Light looks like it turned but lost intensity. Case C: Add the third 90 degree polarizer back in and do the same again and you get 25% light out. If this model is accurate, this seems straight forward to understand intuitively without misrepresenting the experiment as showing weird quantum-effects as many publications do.
Great video. At 94 I am still trying to learn!
That’s amazing!
So nice of you!
I just took a class on Quantum computing. Its theory was very elegant(I tend to skew towards complexity theory), but watching this practical video was pretty inspiring. The most beautiful theories have the simplest experiments.
This is the first video I have seen that actually explains what happens inside the quantum computer instead of simply saying that qubits are in the state of 1 and 0 at the same time
I love the Win95 UI of the animated computer screen :)
You explain things in a way I can understand. Thanks for making this information available to the average person. You are an excellent teacher.
Mithuna, I was a fan of your whiteboard videos from almost a decade ago. Didn't realize you had returned to making videos until this got recommended to me (I thought I was a subscriber, who knows what the algorithm is up to) and it's such a breath of fresh air. I'm so glad to see the same clarity of thought in this new format.
I don't know for certain if this is why, so taken with a grain of salt, my intuitive sense for why light travels slower in a medium is because it bounces around from from molecule to molecule which slightly increases the distance traveled before reaching the destination of the measurement. I imagine it kind of like having several small mirrors spaced out and aligned on top and bottom in front of a laser to create a zig zag pattern that ultimately reflects the laser onto a wall to be measured. You can shine the laser straight onto the wall, or you can tilt it to zig zag across the mirrors onto the same spot. The wall is the same distance from the laser in both cases, but the laser light travels a further distance to reach the destination when it bounces off of the mirrors. It's like traveling in a vertical line, and then adding in some horizontal distance. I haven't really looked into how it works, so I could be wrong, but this is how I imagine it. After all, a vacuum is just empty space, and a medium is space + matter. Since fundamental particles don't really occupy the same space at the same time, I imagine putting a bunch of particles in the way of the light would alter its course a bit.
Loved this video! Can't wait for the next one. I especially love that it allowed us to see some of the "figuring it out" part. Being from the South in the US, I laughed out loud at "the hell?".
Fantastic :)
Now I can understand why a cubit can have two states at the same time. It has a little bit more of the up and a little bit less of the right.
And when the computation is right, we can have the result we wanted in the first place.
So you “set” the answer. And then try to find the right question :)
What a creative and intelligent approach 😊 thank you so much for encouraging people to experiment and try it out themselves
Your videos are always so well made. Learning made this fun takes a lot work and a lot of skill - and you have both. Thanks!
Thanks for the video. This experiment looks more like a demonstration on the classical interpretation on polarization of light than a quantum computer.
Wow I can't believe it's been years since I joined this channel! It's been a great ride and I've gone from a guy doing a bachelor's in physics with no clue about his future to a PhD student in quantum gravity with no clue about his future XD. It's been real fun!❤
Oh man, I know this ride well… what are you thinking you’ll do next :)?
@@LookingGlassUniverse
Postdoc most likely.
I love physics so I'm gonna stick to academia for now. Still I'm years away from that decision.
I've always loved your videos and missed them a lot. you have a unique way to present matters visually very clearly while also making it fun, bizarre and a bit magical.
Thanks to your incredible videos and style of explanation, my understanding of quantum mechanics/computing keeps getting better and clearer! My niece too loves your videos and wants to build a quantum computer one day! We both hope you keep these videos coming! :)
8:07 So if I understand it correctly, it's basically like working with vectors.
The horizontal one is along the x-axis, the vertical along the y-axis and by changing the magnitude (strength) of these vectors, you can change the direction in b/w these two states, of the resulting vector that is
You are good at explaining difficult things. Thank You.
Big fan of the plain English explanation for some of these concepts!
This is awesome, I'm so glad you put this together from things pretty much anyone can get and also explained it! Visual computation is so interesting to watch... idk why lol.
What a fascinating explanation and demonstration, thanks!
excellent video! thanks for this fascinating perspective. I don't have the time or money to get a PHD right now so this is helping me come up with ideas for building the one I have wanted to for about 20 years.
I hate doing (physical) experiments also. I just login to some place, and do it online. (I'm now too lazy.)
A few years ago, I used IBMQ. (I think it's called IBM Quantum, now.). All in Python. Introduced me to different gates, such as Hadamard and CNOT gate, the concepts of superposition and entanglement. Can also just do it with linear algebra (matrices), though for only very simple cases. But enough to demonstrate the concepts. This is assuming a STEM background, but without knowledge of quantum computing. (This maybe a little bit more than your intended target audience. But it's another way to get an introduction.)
Perhaps one of the best videos I've watched in a very long time. Thank you so much! This is amazing!
Probably a very silly question, but here goes. In the video about light slowing down in water it was explained that the moving electrons re-emit the light, but in the explanation of the polarity filter here it is suggested that the electrons just absorb all the light.
Very cool that you were able to buy some spinors and SU(2) matrices for building a quantum computer. :-)
Yeah, weird they were just selling them online
I could watch you explain anything anytime anywhere and still be interested 😊
I love your videos! They gave some of the key tools for me to study proper quantum mechanics courses. Your explanations are also very straightforward and fact-based. :)
Its got nothing to do with the video but I have some calcite myself when I got curious about its ability to aid in navigation: By placing a dot on one side and looking through the other on an overcast day you can find the sun by making the dots you see the same brightness. (By who and to what degree it was used in this way in history is a little contentious, but it does work.)
Such a cool idea! Thank you :)
i love the cute little Alice animations.
I love the evolution of your videos. I loved your voice and your voice over animation, but these are definitely a step up.
Calculations on a home made quantum computer? Woooooow can't wait :)
I'm taking a class about this and this made it more intuitive! I learned the math, but you helped me understand the logic of it! thanks!
Very nicely explained.
Some questions:
1. Laser light passing through a half-wave plate followed by a polarizer is a single qubit quantum computer. Is this a correct description? If yes, what exactly we are computing?
2. Why the light beams of H and V polarization are 'entangled'?
3. If we repeat the same experiment using radio waves, is it still a quantum computer?
So the light is made of electrons. Got it.
6:23 seems like an excellent time to tell people about the logic RM3, an SMCC, a symmetric monoidal closed category, also the name of my cat Mr. SMC Cat.
INCREDIBLE. CONTINUE. You have all my moral support.
Brilliant. Amazing skill explaining complex stuff with simple models.
It's a bit crazy how divorced physics education is from hands-on experience. It would be nice to play around with the phenomenas we're studying on the blackboard every once in a while.
I would disagree! I’ve done a lot of education and the subject that got the most demonstrations was definitely physics! Especially the broad strokes intro classes. Once you get into the more extreme stuff it’s a little harder to play with the material without really expensive equipment I think.
@@bobthemagicmoose That's a fair point.
When the light passes through the polarizer, why do the electron jiggles “absorb” the wave instead of creating their own wave, like the glass electrons in the “does light slow down” video?
I usually never leave comments, but this video was just way too good not to. I love the genuine curiosity that you radiate!
I am genuinely grateful you make such a brilliant effort to share your experience and wonder of nature with us plebs.
Very good video, makes it a lot easier to understand. I do have one complaint, the idea of an electron as a little ball. This, while fine from a mathematical/chemistry perspective is not accurate for what is actually happening. Let's say you have a dam, with the gate open and water spraying out the bottom. The entire stream going down the river is the negative charge (electrons). Where as the funnel inside the dam, the suction, is very localized (proton, positive charge) it is only in one location, it doesnt really move. However one does not exist without the other. The big long stream of electrons does not exist with out their source, the opening inside the dam. Electrons are a unit of measurement, not a little marble. Much like a gallon is a unit of measurement, not a thing.
I can see how rotating the polarizer works at "rotating" the polarization, but it seems like moving the filter closer or farther away would also "rotate" it. I.e., what's the difference between phase angle and polarization angle of an EM wave?
BTW, 3BlueAnd1Brown did a very nice video on how glass slows light. Feynman's lectures also has a well written chapter on it. Basically, EM waves jiggle electrons and the jiggled electrons create a delayed wave that adds to the transmitted wave and causes a phase shift that, effectively "slows" the light.
It's nice when youtube does a good job of showing me channels that are new to me that I will enjoy.
I like these videos. It demonstrates that voyage of discovery in science that is so important for learning science. Note on safety, although I am sure you are using Class 1 laser pointer which are safe without needing protective eyeglasses, people watching this are going to want to repeat the experiments themselves, and if you buy laser pointers from the internet they might say they are Class 1, but in fact be far more powerful. So I think wearing laser protective eye-ware in videos like this would set a good safety example.
The explanation using lined paper was very good!
Not a bad idea. But the part of entanglement maybe easier if splicing tight into two beams and ket to different route and compare at the end
I got caught up in stalking your channel to learn more about quantum mechanics/physics/engineering when I’m in a general chemistry class learning about surface tensions… I’d much rather be here.
Omg, I just found your channel, and I love your content. Your videos are so underrated and deserve more likes!
Fun to imagine.
Bonus extra Feynman type guessing a QM 1st of April at Christmas time..?
Love the honest presentation of Quantum Computational Logic proving that the design is useless. The Looking Glass Universe analysis is essential to decode the confidence of the Designer, primarily to demonstrate the illusion of separation, as impossible as BBT discrete-ness, and you notice that the Universe is logarithmic condensation modulation in/of instantaneous i-reflection at the Centre of Time Duration Timing, ie purely thermodynamical => mathematical superimposed motion-> Act-uality of relative-timing interference positioning resonance bonding dimensionality.
It's not Caterpillar food after all?
Allow "Spin" to be the Totality of Singularity-point positioning Conception, of a Looking Glass Universe.., equally useful to imagine.
"It's called research" because we don't know what Experiments are for? Serendipity, learning by doing experience and getting a different result is the lottery winner's rationale for gambling. Useless for Quantum Operator Logic.
Truth in Labelling? Entanglement entertainment is an experimental success?
Im doing quantum computers for a EPQ and this video has been really helpful. Thanks!
That was a fun video. Thank you for making it!
Hey, Omg the timing couldnt have been more impeccable, me and my few friends recently a few months back successfully replicated a Bit assignment protocol in a Quantum Optical Laser system, it would be wonderful to talk about it and how you could have used that instead of a BBO or maybe an Axicon, the operator mechanics there is much to complex and has issue with Heralded photon detection. We would be more than happy to discuss and share our protocol if that is something you want to replicate / try out.
Cheers