Quantum Field Theory visualized

How to reconcile relativity with quantum mechanics ? What is spin ? Where does the electric charge come from ? All these answers in 15 minutes !
0:00 - Introduction
1:52 - Field and spin
4:38 - Conserved quantities
6:02 - Quantum field
7:39 - Standard model
10:15 - Interactions
13:58 - Conclusion
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Alessandro Roussel,
For more info: www.alessandroroussel.com/en
_
To learn more :
en.wikipedia.org/wiki/Quantum...
en.wikipedia.org/wiki/Symmetr...)

[@ScienceClicEN]

Many thanks to my friend Thomas Harvey who helped me write this video. Thomas was my roommate during my Master's at Cambridge, he is now doing a PhD at Oxford University, and quantum field theory is his daily routine : www2.physics.ox.ac.uk/contacts/people/harveyt

[@doc7115]

Hi sciclic. Thank you very much for this beautiful illustration. I wonder if you can recommend some textbooks on this subject?

[@Sam3532]

Is so obvious u go to cambridge\oxford. You’re over pronouncing the words.. wtf? Is just try hard and overly preppy. Alienating. Unless u think ur a cut above other ppl because ur clever and/or go to a good school. Not a bad thing, good studies get done at these places but stay human and don’t think ur better than other ppl because ur part of some elite club that speak like they have a silver spoon up their arse

[@ScienceClicEN]

@Hugos Thar Actually it's not me speaking in the videos, I am French and my English accent is terrible so I asked a friend who kindly accepted to record his voice. Octave is doing a great job helping me translate the videos

[@Sam3532]

@@ScienceClicEN yes you are correct and I’m just angry. That sounds sarcastic but I promise it’s not. Lol sorry. The way he said v-A-ries, as if the e had no effect on the a, reminded me of things not worth mentioning, but made me angry and caused me to react with vitriol, for which I apologise. Maybe the manner in which I’m saying this makes it seem disingenuous, but it is the exact same reason why I was angered by the seemingly arrogant mispronunciation of certain words. It is however, as you correctly state my ones accent is not something to hold against someone. Not to mention a separate issue to the content of the video which I do actually value; so unsure why I let this negativity cloud my vision

[@CornishColin]

@@ScienceClicEN I think the English sounds pretty normal to me - so your friend did a good job. One or two “scientific” words to me are pronounced a bit odd with emphasis on the wrong syllable like “annihilate” or “temporal” - Other that that pretty normal. I did a B.Sc in Physics 30 years ago but became a geophysicist professionally - so I’ve long forgotten the maths but it’s really great to see the animations you are doing. I particularly like the space time animation you did in another video - I’ve always struggled with the rubber sheet analogy.

[@scottt9382]

Speaking as a physicist, this is SUCH an exceptional explanation of QFT.

[@aaronm.3581]

Try speaking as a toad. It will better suit you.

[@andreyrushchenko2378]

lmho - this is just nice graphics but nothing more...

[@socratese5]

@@andreyrushchenko2378 i would love to see your explanation then 👍🏽 Is it possible to see or hear it online?

[@didierborne166]

I think they have not posed the questions that divide QM from GRT. Maybe here is a bit of a revolutionary idea about the Electron kzbin.info/www/bejne/Z4GnZKiufd6bq7s

[@isodoubIet]

It's an extraordinarily confused explanation of QFT, illegitimately mixing together bits from canonical quantization and Feynman's path integral, as well as interpreting Feynman diagrams as real field configurations when in reality virtual particles are off-shell. Philosophically it's wrong too, since it forgets that as in every quantum process all you get at the end are probabilities for the various measurements, whereas what was presented here gives the impression of something like a Fourier sum just giving classical physics. I have no idea what a layperson would get from watching this but it wouldn't look much like what physicists do when they do QFT.

[@user0K]

Wow, someone actually described what spin is

[@Sifar_Secure]

I know, this is a wonderful lucid explanation. I've watched videos where famous physicists talked about spinors and I was left feeling even more perplexed.

[@jigartalaviya2340]

@@bobbobson6867 Can you do even a little better then?? Sort of.

[@duprie37]

Just what I thought. Also just how virtual particle interactions forge the paths of particles. Heard lots about Feynman diagrams and sum over all paths but not seen those so nicely intuitively linked before.

[@mroygl]

It lacks an explanation of what the hell to turn the universe around a particle for at all.

[@duprie37]

@@mroygl So you can determine their spin.

[@stetsonlewis3095]

As a visual learner, these animations were incredible and helped immensely. The writing was also crystal clear and paired perfectly

[@MuffinMan87]

Exactly! I don't speak Greek. But, I can look at their graphs and animations and write my own that results in the same conclusions.

[@bas_ee]

@@MuffinMan87 Greek? Its an english voice?

[@MuffinMan87]

@@bas_ee Greek is the language of physics. I don't know what most of their letters are called. It had nothing to do with the narrator's voice.

[@vaunjeis6751]

12:23 blew my mind because while it is useful to think of a string as vibrating at a particular frequency, the truth is indeed that any given section of the string is vibrating differently from the rest, and it is the synthesis of all those parts of the string at once which produces the final frequencies. Once of the best ways of describing wave function I have ever heard.

[@socalpotato]

Eloquent, and elegant. Even if you’ve never had opportunity to mess around with a guitar, you can apply it to a speaker just as well (for all the bass-heads out there). I’m relatively certain that everyone has seen a speaker vibrate at some point? That’s probably naive on my part because some places just have different instruments due to culture and geography.

[@phrastro7075]

right??? like it made so much sense

[@benbarkerdreaming]

I play guitar and Didgeridoo simultaneously.. I've gone into what my people the biripi Dunghutti of Australia call the dreaming...a continuous timeless place of creation ... The analogue of the vibrating strings and all the frequencies coming together to create the actual sounds is an amazing interpretation... Because it allows you to see it from now of a creator perspective and even ask .. "who is playing the guitar"? ...or what lol

[@meatmanjam]

that same visualisation can tell us why instruments sound different playing the same notes, when they are of course only emitting a series of sine waves at similar. frequencies. The dominant sine waves in that series will be harmonics of the intended/heard note: eg heard note at 300Hz: 2nd harmonic at 600Hz, 3rd at 1200Hz, etc. A particular guitar E-note string may have the root, 3rd, 4th and 12th harmonic at the largest amplitudes, whereas a violin E-note string may have root, 3rd, 10th and 15th. This simple difference in the combination of the harmonics is what determines the timbre and therefore the signature sound of one instrument compared to another. It’s why speaker cones can recreate every instrument- they just emit the right combination of sin waves at the right amplitudes.

[@monx]

this analogy doesn't work for me. it does not explain the principle of least action. the harmonic vibrations of a string do not "collapse" to a single frequency, but exist completely independently, robust under measurement. it's only in human auditory perception that these overtones "collapse" to a single timbre.

[@danival2090]

Excuse me KZbin, Why did it take 2 years to recommend Fermilab vids to me from PBS Spacetime and 3 years to recommend ScienceClic vids to me!? This is beyond superb content!

[@jaredf6205]

Check out Science Asylum, that's the other channel that helps these types of things click for me in the way this one does.

[@theoreticalphysics3644]

@@jaredf6205 I just found that channel, finally understood tensors and the field tensor for my gr class after watch just one video there.

[@pricett434]

And I just found this channel only a couple of days ago already being subbed to both of those channels for years, it's SO good!!

[@tophan5146]

I can’t stand Science Asylum host and the presentation, it’s a shame because the information is very good

[@tim40gabby25]

@@tophan5146 Bit marmite, I guess?

[@nicholasbohlsen8442]

The animations in this video are extremely impressive. They present some of the basics of QFT, much better than many other casual sources. (and visualisations like this are also almost unavailable in an academic context as well)

[@ScienceClicEN]

Thank you very much ! Took a lot of time to find good visualizations

[@rodvanmeter517]

@@ScienceClicEN Did you make the visualizations yourself? What tools did you use? I'm always trying to learn how visualizations that I admire are constructed.

[@MarkRuvald]

@@rodvanmeter517 i find many illustrations made in Mathematica are well done.

[@ahitler5592]

What is QFT? Quantum Fuck That?

[@lumotroph]

Agreed - the animations here are superb.

[@effortLus]

This particular video was way too complex for me, yet it was fascinating to just watch and try to understand bits and pieces. It's incredible how even the most difficult type of information can come across to the most simple people, as long as its explained in a proper way. Good job

[@Life_42]

I agree!

[@DanoshTech]

Just ask me what you didn't understand maybe I can help (just don't ask me about energy quantinization I'm still learning about that)

[@qwertydavid8070]

@@DanoshTech I think I got lost when he started talking about how the spins are "abstract mathematical ideas". The way I understood it, in an extremely simplified way, is that quantum field theory is essentially a way of modeling a universe using just pure math that happens to describe our actual reality. I think it'd be useful if he described how a specific spin (or combination of spins) is meant to symbolize an actual particle. That's what I got out of it at least: particles are just complex combinations of spins, whatever spins actually are meant to be, I'm still kinda lost on. I also got lost around 4:45. What is that y-shape supposed to represent? Is it two particles combining into one? I think it's also fair to advice that I'm no physicist or anything. I'm just a curious teen that's trying to learn more about the world. I admit that I don't understand these concepts the way they're meant to, these are just helpful visualizations that'll help me when I actually need to tackle these concepts eventually. I'm a very visual thinker, it helps me to imagine things in this way. I understand that when you get to such small scales the concept of visuals and distances kind of breaks down, and imagining things visually is kind of useless, things tend to get more mathematical and abstract. Still, having some sort of visualization, even if somewhat inaccurate, helps my brain wrap itself around weird concepts like this.

[@worker_ivan_from_tver]

​@@qwertydavid8070 I guess in 4:45 author just wanted to illustrate the conservation of momentum. So yes, basically two particles (doesn't matter which) with opposite values of momentum components along the horizontal axis glue to each other and thus their opposite components of momentum just neutralize each other

[@juzoli]

Just keep watching these videos, from different authors too, supplemented by books and other material. This is not a subject which could be understood from a single video, even if it gas the best explanation ever.

[@cheahshuhuan2018]

I studied QFT during my master's for a whole year and the lecturer lost me quite early on in the course...This video presented a visualization and explanation of QFT in such an incredibly understandable way that much of the confusion in my mind was finally cleared up! Thank you so much for creating this video!

[@PhoticSneezeOne]

This visualization is so advanced, its like partaking in future starfleet academy education

[@TheKingofKingscorona]

I think it makes sense if always wondered how the world works

[@Gunth0r]

You nailed it.

[@locke8847]

That's just your brain's pattern recognition associating the boxes around the 9:30 mark to military insignia badges like chevron patterns.

[@locke8847]

@@BasiliskInTheSky Happy octopus

[@rolux4853]

@@brandonm9579 I don’t understand what this has to do with the content of this Video?

[@uhbayhue]

This is by far the best explanation of QFT I've ever heard. This video seems to go by very slowly, but in a really nice way. Dont know exactly how to describe it, but thank you!!

[@ScienceClicEN]

Thanks glad you liked it !

[@Kugelschrei]

I believe it's the pauses. They give room to comprehend the explanations

[@bmoneybby]

It's extremely impressive!

[@zovisapphire]

This is EXACTLY why I like these videos. concepts are explained visually, pacing is slow enough for actually grasping the information presented, while being fast enough that you don't lose the thread. The background music track helps with this IMMENSLY. Maybe it's just me but that + speaking speed + information pace in a great balance is probably the most important factor when educating.

[@santzerosantone]

kzbin.info/www/bejne/p5fMYamXd7KhiqM

[@vladip7662]

Best short presentation of QFT I've ever seen. And it fully complies with what Einstein once said: “Everything should be made as simple as possible, but no simpler.” Great work!

[@birhon]

thats an awesome quote

[@sadariuswolf]

I just found your channel and I had to say this is the most fun I've had in learning and understanding at least specifically Quantum Theory, and I do mean fun. You come at it like we would have in college, starting by building the theory piece by piece. But your script and breakdown level made it the most comprehensive I've ever seen. Your pacing is also incredibly satisfying as you give time for us to process the new words and topics, digest them enough to feel like "I'm not 100% there, but let's trust the process" and then link the non-visual phrasing with the excellent visualization. This is an incredibly satisfying way to learn, for me at least. But your script writing and outline is a huge part of me coming away actually understanding this on a level I really wanted to when I clicked on it.

[@mikudubskasai8725]

We’ll critiqued ❤

[@artsenor254]

You know, I'm a physics student, currently learning all of this stuff, and I've been searching on KZbin for months to find some way to help me visualize QFT beyond all the equations on my sheet. Well, that's the exact video I couldn't find, thank you so much for this amazing work !

[@ScienceClicEN]

Glad you liked it ! I've just finished my Master's and same as you, when I was studying I looked online hoping to find intuitive visualizations, but couldn't find anything convincing

[@monkeyrobotsinc.9875]

im a physicis student too but i only study on youtube

[@isodoubIet]

This explanation is fine for a more casual viewer but if you're actually learning physics I'd advise you to be cautious of it. 5-second long snippets of this video make sense in isolation, but they don't really form a cohesive whole -- it's as if someone mixed three different jigsaw puzzles of the Eiffel tower together and presented various bits of it as if they formed a single picture. There are pieces of several different 'perspectives' of QFT in this video, but they're not all true at once -- you have to pick one or the other. For example, the author says that to turn a classical object into a quantum object you "allow it to adopt several positions at the same time, with more or less probability" (which isn't quite right but it's a common enough so let's leave it aside for now). Then it is asserted that to turn a classical field into a quantum field 'we allow it to adopt several configurations'. The trouble here is that the former is describing so-called canonical quantum mechanics -- wavefunctions and so on -- whereas the latter is really describing Feynman's path integral formulation. The correct comparison should be between particles taking all paths between two points A and B, and fields taking all (time-dependent) configurations connecting configurations A and B. It's a subtle difference but an important one -- when doing canonical quantum field theory one doesn't deal with superpositions over classical configurations, but rather with superpositions of definite particle number -- there's an uncertainty relation between particle number and field intensity, so there's a possibility of confusion with the next point as well, since the presentation suggests that particles are associated with the fields being in a given classical-looking configuration but that is very much not the case. Anyway, the point is, if you already know QFT it's easy to sort out these various jigsaw pieces from one another and pick out the kernels of truth in the presentation, but if you're still learning you run the risk of ending more confused than when you started. I don't mean any disrespect to the creator of this video -- it's of course a laudable effort supported with really well-done visualizations. QFT is one of the hardest subjects in all of physics so it's unsurprising that it's hard to convey it in a way that's both accurate and understandable, and I think on average the video is useful for a layperson who wants to have a better idea of how this works. But if you're serious about learning QFT you need a presentation that perhaps sacrifices a little understandability for accuracy.

[@tokyomobster3072]

@@isodoubIet I completely agree. I'm studying for my QFT exam and I felt that the video hopped and skipped around all the important parts of my module. I felt so confused by this video I didn't know whether it's actually correct or not lol. At the very least, it's very pretty.

[@mr.username]

Truth is -- QFT is complicated. There is just no way to put it simply. While the visualisation is well-made indeed (thumbs up to the author), it is unfortunately not rigorous and should not be regarded as such. Vanilla QM has quite a simple mathematical apparatus, and yet its mapping to the real world holds questions which after a century nobody can fully answer. And in case of QFT *both* of the aspects are complicated.

[@guyedwards22]

You just explained quantum spin in a perfectly sound, fairly simple mathematical context without resorting to the tired line "particles don't really spin, but you can think of it that way". I'm absolutely blown away man! Also, I'm a huge fan of how you symbolized conservation laws by their corresponding transformation symmetry in the appropriate spaces. Not super necessary to understand the content, but a nice little something extra for those in the know!

[@robertthomason8905]

Spin and vibration have similar effects. You can only spin a solid so fast. Plasma can be vibrated and accelerated to create cool quantum vacuum.

[@matttzzz2]

Why the fuck dont you nutthuggers timestamp your comments?

[@blurta2011]

But it is still just all made up, it doesn't mean a thing, you people just suck this crap up and tell these people how clever they are.95% of the people watching has no idea what this guy is talking about

[@blurta2011]

But it is still just all made up, it doesn't mean a thing, you people just suck this crap up and tell these people how clever they are. 98% of the people watching have no idea what this guy is talking about. Watch it again and tell me you know exactly what he is talking about, all these wonderful particles with their wonderful names and then there is the anti matter

[@blurta2011]

​@robertthomason8905, just keep believing it, I am sure you knew exactly what you just said

[@fonkyfesh]

This is the clearest and most thorough explanation of quantum mechanics i have ever seen.

[@singingcat02]

I'm a high school student and this video seemed interesting especially since i'm in my physics phase, and my mind is blown. That is so interesting, and i managed to understand most of it thanks to your incredibly clear explanation and visuals. I might have to watch it a few more times to memorize and understand it better, but it makes me want to dig even further into the subject. Thank you !

[@ritishify]

I wish you a lot of success in your education, it's good to see younger people seriously interested in this stuff.

[@kieranwagstaff]

I mean, scary monsters are great and all, but it's this stuff that keeps me awake at night.

[@jandroid33]

What scares you the most, quarks or electrons or something else? :-)

[@LouSaydus]

As long as you don't think about vacuum decay you're fine.

[@pronobsarker3828]

@@LouSaydus some eldrich stuff

[@nobodyinparticular968]

@@LouSaydus i feel like we're more likely to die from a rogue black hole then vacuum decay

[@NeurotiQ]

@@nobodyinparticular968 don't worry, vacuum decay or black hole is nothing in comparison with our reckless stupidity. We will destroy ourselves I bet 🤣

[@Geddyfleaharris]

For a non-physicist layman, who just happens to enjoy reading and watching KZbin videos about it, your videos are fantastic. Great work. Keep them coming!

[@lawoull.6581]

Do you like collard greens??.🤔

[@vladimator1842]

@@lawoull.6581 Right here...👋

[@rachelnyn5543]

@@lawoull.6581 I like color green…does that count? 😆

[@lawoull.6581]

@@rachelnyn5543 ...it's a vast universe....you're in.. yesss

[@mozzerianmisanthrope406]

As a philosophy student this is fantastic. I have never considered paying attention to physics, but I understand how important it is to the world around us and the intersectionality between quantum mechanics and philosophical concepts has blown my mind. Absolutely fascinating, and you did a great job in making it super easy to comprehend. Thank you.

[@danieljones4032]

A fitting review, indeed

[@NalitaQubit]

You will enjoy then listening to Sean Carroll; he has a Patreon account which is the best way to expand one’s brain horizons.

[@jdbrinton]

Bravo. Best QFT summary available. Your work is truly a donation to humanity.

[@lorenzozappa3347]

Wow, I am actually studying this stuff but I often get confused by algebra and I lose the meaning behind. Your video is absolutely amazing, everything is explained in such an intuitive way. It reminds me what I am doing when I get lost in equations. Thank you very much!

[@ScienceClicEN]

Very glad this can help you ! Good luck in your work, QFT is very interesting

[@thesciencehinduby]

Hi Lorenzo I am a novice. But can understand maths ans enjoys. Please recommend a book on QFT, the one I have is too complicated for me. I have Introduction to QFT by Peskin and Schroeder

[@paperbitch123]

@@thesciencehinduby the lecture notes by David tong are pretty good, also free :)

[@youtubesucks1885]

@@thesciencehinduby Peskin in Schroeder give by far the best substantial introduction to QFT available

[@bezbezzebbyson788]

@@youtubesucks1885 Peskin is good if you already know qft

[@kuboteusz]

Did you just explain what an electromagnetic force is. Wow

[@PawlTV]

This also blew my mind.

[@YaBetterHide]

This also blew my mind

[@herrunbekannt3822]

I had to pause and think through exactly that thought. Blew my mind.

[@aurelienyonrac]

🙀 mind blown

[@justinsturgeon6948]

no he did not

[@deldarel]

I'm consistently impressed by how well you simplify and explain the necessity of things. Within 2 minutes you shows not just that we have fields, but why it's necessary we have something like fields. You don't just explain fields have internal symmetries, but also show why their nature necessitates these. If there has ever been a channel that could make M theory digestible and captivating, it's this channel

[@extraxt]

This vídeo is fantastic. The biggest win of it is to have this micro pauses between concepts and examples, its 10x effective for me stead of having to watch the video over and over again. 10/10 for this video, keep the great work!

[@scifactorial5802]

Hands down one of the best introductions available. Love the visualizations, basically you are the 3b1b of physics! Absolutely deserves more views! Please keep up the great work with more videos like this. Excellent stuff! I might have missed it but is there a video about how you do the visualizations?

[@ScienceClicEN]

Thank you very much for the compliment 🙏 I am very glad you like it. Not yet no but I might do one in the future. Basically I draw the images with Photoshop, and then animate them in 2D / 3D using After Effects. With time I've learned a few tricks to optimize my workflow so I can produce better looking results

[@Pidrittel]

Very very impressive!

[@haotiangan2747]

@@ScienceClicEN You are amazing

[@tokyomobster3072]

@@ScienceClicEN I would recommend learning Blender

[@ScienceClicEN]

Yes I use Blender for some projects, it's great! (I used Maya before but switched to Blender a year ago), but for these videos as it's mainly 2D I am more familiar with AE

[@greptheloot]

Seriously...thank you for taking the time to animate this and provide visual context to these theories. A rarity on youtube, instant sub!

[@ScienceClicEN]

Thanks ! Glad you liked it :)

[@anthropomorphichuman]

This is an amazing explanation, wonderfully done. Great job - I think a lot of people have had concepts snap into place after watching this visualisation. Great soundtrack choice, too

[@LewisBavin]

Just guna echo what everyone else said but this is INCREDIBLY digestible. I have watched and read a crazy amount of videos and papers about quantum mechanics but this visualisation has completely contextualised everything I've learnt in a way that makes me understand it so much simpler. Incredible video

[@Life_42]

I strongly agree!

[@neerkoli]

This is one of those "woah!" moments for me. You have that gift of explaining things clearly and precisely. People like you are making ordinary mortals like me understand quantum physics and relativity, at least a little bit. Thank you!

[@CitizenAyellowblue]

The guitar analogy really hit the spot!

[@yash1152]

12:30

[@yourself88xbl]

Yes! Especially after I just learned about the nature of overtones which is you hearing the individual sin waves that make up the superposition and learning that sythisisers are just computers that synthesize sin waves. 🤯

[@pascalfragnoud2846]

But, what if the guitar has a vibrato ?

[@yash1152]

@@pascalfragnoud2846 any example video? so that i can see and reply accordingly?

[@pascalfragnoud2846]

@@yash1152 Oh, that was just a joke ! But alright, I'll play the game. The part where the strings meet the body of a guitar is called the bridge. There are many types of bridge, but mainly we can split them in two categories: fixed bridges, and floating bridges. What is special about a floating bridge is that you can move it, usually with a thin metal bar, which has the effect of changing the length of the string ever so slightly. Changing the length of a string will in turn change the frequency at which it vibrates, and thus change the note. Floating bridges have many names, a familiar one being vibrato (which may be confusing, as this word is also used for a different albeit not totally unrelated thing). The typical vibrato is the one used by Hendrix for the famous diving bomb effect. You can see one in use by Jeff Beck here (You can see the vibrato bar pretty clearly around 20 seconds, and he uses it regularly though the whole video, or even through his whole career) : kzbin.info/www/bejne/pIKnm4Z9o9KMeKs If you type whammy bar in youtube, you'll find a thousand videos showing exactly what I was talking about. I personally don't use them much, but it's a quite fun little thing !

[@trewillz7425]

Incredible work!! This SHOULD be in schools. Absolutely amazing visuals and very descriptive.

[@kyoto9916]

I've never seen such a good and simple description of something so seemingly complex. And it's mind-blowing that someone actually once came up with this concept by merely observing the universe

[@umi3017]

Physicist: spinor Me: oh, you mean USB(typeA) connector?

[@AttilaAsztalos]

And this is why I read comments before commenting. Came to say the same. Clearly!

[@JavierAlbinarrate]

LOL.... damn good one! hey, this comment should have thousands of likes... here you have mine, just one is all I can give unfortunately :)

[@mohdrazif777]

Damn.

[@yash1152]

what does this mean..??

[@notgonnalie1846]

I salute you for making me feel even more stupid

[@Grzyb032]

Beautifully explained, am gonna share it with friends that are also into this stuff

[@ScienceClicEN]

Thank you that helps a lot 🙏

[@djtomleeuwen]

I'm quickly done with the sharing...

[@polymloth]

I’m also gonna share it with friends who are not into this stuff bc maybe they will be after watching this

[@sunnykaura8397]

This is an outstanding explanation that brings so many threads together. When someone can make something very complicated sound clear and simpler for you, you know they have a proper grasp of the subject matter.

[@MyskokorwEpikz]

I'm a MSc student in particle physics and I must say that these are some of the most well made videos on theoretical physics in layman's terms I've ever seen. Many other pop-science videos on youtube can't maintain accuracy when simplifying the concepts and making them aesthetic and captivating, but you have managed to do both. It's a great accomplishment! I have a question: Do you think modern physics have been established for so long that it's time to teach it from the start, and skip the "detour" through classical physics that traditional teaching does? On the one hand, classical physics teaches you how to work with a physical model that can be cross-checked with your everyday physical intuition, on the other hand it reinforces intuition that you later have to unlearn when learning modern physics. But maybe this unlearning is good, since that is probably what we need to do anyways for the (hopefully) next paradigm shift? Studying several incompatible models might make us more open to new models?

[@Userkzb20253]

I think it’s an overkill if engineers skip classical physics. It works so well for the real world except the two extremes. May be physicist students should skip classical mechanics.

[@PatricioHondagneuRoig]

How dare you make the meaning of particle spin finally click in my head? No videos should be this good.

[@scepticalchymist]

Beautifully animated and impressively clear, concise, and comprehensible. A true piece of magic.

[@zucc4764]

this is an awesome explanation of how electrons repel each other and how they fit within a quantum field. really appreciate how you hit us with Feynman diagrams without making it look too hard to digest. also makes me appreciate how close we are to arriving to a theory of everything. excited about what comes next in QFT.

[@captainprice2331]

It is masterpiece, I remember watching this a few months back and banging my head but since they I have gathered some more mathematical and physics knowledge and now I totally got the video and I fell in love.....

[@macronencer]

Why have I NEVER before seen that explanation of spin? I'm not a physicist but as I studied maths, it immediately made some sense to me. Thank you!

[@darthnihilus4074]

The best analogy for me is the deck of cards analogy. Imagine a king of hearts. It has two heads, one on either side. You have to rotate the card 180 degrees for there to still be a head facing up. Therefore it’s spin is 2. Imagine a ace of spades. You have to rotate it 360 degrees so that it is facing upright again, because it is not symmetrical. Therefore it’s spin is 1. I hope this makes sense!

[@yash1152]

​@@darthnihilus4074 yeah, same thing with vectors too (as shown in the video - 3:45) - but yeah, urs one is more layman. and as with most things, the mathematical description requires less words but that's somewhat compensated by the requirement of more background info lol.

[@actuallyawful]

@@darthnihilus4074 that's because the rotational symmetry is given by 2*pi/spin

[@RomainPuech]

One of the most relevant video of the Science KZbin Game

[@psicologiajoseh]

I think the same as I read in a previous comment... Arguably one of the best science channels out there! You really can see how much he understands these topics as he explains them with so much propriety and simplicity.

[@stevenhoman2253]

As a recent subscriber who stumbled across your channel, it is gratifying to see such fine representations and explications of dynamic quantum fields. Keep up the fine work.

[@Chrisbajs]

13:19 Eureka-moment for me. THIS IS the electromagnetic force!

[@carlandren7062]

Still don't understand why the particle was emitted in the first place though

[@Owlrrex]

@@carlandren7062 Because it's allowed. On macro-scale, you what is observed is the summed result of all possible scenarios. In that sum, all possible scenarios have to be considered: What if 1 photon is emitted, what if 2 are emitted (and how), and so on. Scenarios with multiple chained interactions at once are less likely, so they contribute less to the final result, but just from probability sooner or later the two (resting) electrons are likely to exchange a photon now and then, w hich makes them move away from each other. Because it's allowed, because it's possible, it will happen sooner or later.

[@protorhinocerator142]

@@Owlrrex Correct. It's an average of a billion zillion random microscopic movements and exchanges. For instance, at the molecular level, every oxygen molecule in a canister is moving in a random direction. But back yourself out to the canister level, and the average interactions are so consistent and predictable, they follow the Ideal Gas Law. Order from chaos.

[@Koodles33]

@@protorhinocerator142 Great example.

[@edfun42]

So the act of emitting photons (from electrons) is the reason why electrons repel each other? And is there a similar reason why positive charges repel??

[@crowbringer]

Great! I like how you make these pauses while you explain stuff. Gives me some time to process what you just said. There are many other great channels here but for the first time I feel like I actually remember something from the video. Sub+

[@voges1001]

Yeah I watched it on 0.5x playback speed

[@sarsedacn]

As a Physicist I'm astonished at the level of accuracy of this video. Well done!

[@ryangleason3559]

It’s truly a gift to have someone who’s put in the requisite cognitive labor to understand these concepts relay them to the rest of us in a way that stokes curiosity and intuition. I’ve gained so much from your content and your work is brilliant. thank you 🙏🔥

[@Kosmologi-Indonesia]

The best 15 minutes of my life. Thanks for the sharing. I'm studying QFT by myself now and this visualization helps me a lot.

[@loroverde1621]

hello, so you understand some of what he said or almost evreything he say, yes i know a year later,are you still there?, this is very interesting anyway, the things we now days can see and understand from the micro world

[@Kosmologi-Indonesia]

@@loroverde1621 just little bit

[@loroverde1621]

@@Kosmologi-Indonesia same thing here with me, but curiosity, AND. SEARCH,NOT FOR THE TRUTH, rader than just a better understandig,all the things, that i have beèn wondering to understend, since i was born, just like you or anybodyelse whit the desire to learn how things work in the universe, before i leave this world = this life,,and ,off course, this body off mine. PS, if i play with the words ,y shall say, this body off mind,

[@StephanieHoltz0220]

This is such a great visual aide to understand something which is (extremely difficult) to visualize/comprehend. I am not a physics major but am still deeply interested in the subject. Please keep making more videos..haha

[@MatsueMusic]

As a hobbyist sound designer and musician, “symphony of the universe” is a very interesting concept. I am not spiritual by any means yet our free will, determined or otherwise, gives us a unique awareness of and connection to this symphony, I hope we can continue to enjoy and understand it.

[@netopir3804]

The precisely paced narration with this timbre of mysterious clarity spoken in an appealing accent is what brings this excellent video really to life…shoutout to the narrator!

[@sxbmissive]

I’ve been watching a video or two of yours (or 3 or 4) each night for about a week, and on every occasion, I am amazed at how well you explain and animate/visualize these complicated topics. Way to go!

[@matthiascoppens2062]

Great video! I especially liked how spin just casually shows up when you're creating relativistic fields. This must be about the best explanation for spin I ever heard.

[@ScienceClicEN]

Thanks ! Indeed, spin is often presented as some weird quantum property, although in some sense it rather comes from relativity as a way to classify mathematical objects

[@matthiascoppens2062]

@@ScienceClicEN I'd love to add Dutch subtitles to your video, but I don't seem to be able to do that

[@charlesdavis7940]

Great expansion. As a visual person struggling for years to understand particle physics and quantum mechanics, I find these to be the most understandable explanations I’ve found. Thank you.

[@craigwatson4460]

This is easily the most informative video I've ever seen on QFT. Thanks for all the time you put into this, and thanks for finally making it clear what spin and charge actually might be in a physical sense.

[@freddytime]

As a passionated without any academic study, I can't thank you enough for this visualisation. It makes it super simple and makes a lot of sense. I had some issue even with simple concepts jumping from QM to QFT, like characteristics of particles, even as simple as particles charge. It has been always a step of faith of particles behaviours which didn't make much sense. Now I believe I can say that charge and interactions are phase QFT waves interactions and their disturbances. I'm still totally ignorant, but at the least I got comfortable to have my own partial understanding.

[@PCGamer1732]

This is absolutely the best summarized description I have ever seen

[@ListenToMcMuck]

Well, @ least the most compact I've seen 'till now. Highly complex it comes along with optimized audio & videofeatures in order to be easily absorbed. & it rushes by with a pretty hard impact on me as well... @ least according to the impression it has left on me. Great stuff d(8)b... & THXxL, muck(8)

[@IrakliKavtaradzepsyche]

I work in data visualisation. I can tell you, these are the best instructional visualisations I have ever encountered.

[@HolyAwe10]

This Chanel is fuel to my soul. Summarizing very complex ideas behind formulas,equations in amazing visuals and narration. Outstanding work.

[@mikeytrw]

This video brought so many concepts I've read about together, and visualised them in such a way I had a 'wow' moment. Thank you.

[@twokharacters]

As a scientist who has heard the theory of special relativity explained a number times, this is the first time it's clicked. Thank you kindly.

[@jayitabanerjee2810]

Why on earth is this channel so underrated?!

[@albertrenshaw4252]

This is one of the greatest videos I have ever seen. I wish so desperately I could animate like this to visually describe some thoughts I have.

[@raysubject]

Another amazing piece. Man, you're making best "easy to understand explanation of complex things" i ever saw on youtube .. first your general relativity visualisation and now this .. GREAT

[@Chauncylew]

Cheers to the day where videos like this go viral and the human attention shifts toward wonder and amazement again.

[@SebastianSchepis]

This is one of the best summary videos of quantum field theory I've seen. Excellent work.

[@SAN-rm4qp]

Simply do not have words for this channel, easiest visualized qft video ever. Wanna say thank you to this person. This channel deserves millions of subscribers.

[@enricolucarelli816]

I am studying physics for fun. Well, it’s more than just fun. It’s passion. Understanding QFT is one of my mayor pending challenges. With this video, I feel like having reached in minutes what other ways would have taken years of struggling towards understanding. Thank you so much. This video is a real revelation.

[@Teo-uw7mh]

watching a youtube video is not studying. If you dont read a proper book on QFT you will never understand it.

[@enricolucarelli816]

@@Teo-uw7mh well, I agree with you that to watch a short video is not going to have the same result as reading a most likely very thick book. But if your point is that, in general, a video can not substitute a book, I disagree. Actually, nowadays I most commonly listen to audiobooks instead of reading them, or, I watch videos of complete courses recorded in a classroom, with famous professors like Feinmann, Susskind, and many others.

[@ForTiorIJohnny]

finally someone who actaully leaves little pauses in his explanation to let things sink in. it´s so important in teaching.

[@yash1152]

and ppl like me speed up to 1.5x lol... i am soo impatient i guess 😅😅😆

[@capsarestacking8765]

These are great visuals for such a complex topic. Thanks for this!

[@manog8713]

Fantastic presentation of complex concepts in Phyics in a short video. Thank you.

[@raifsam3408]

amazing explaination, as a experimental particle physicist, i'll give this a 10/10 for the content!

[@gaborszucs6075]

Me too, I agree.

[@tim40gabby25]

9 out of 10 for your spelling, but who cares :) May I ask - why do you think there appears to be so much (professional?) disagreement about the usefulness of this video, underneath the lovely images? I'm totally an amateur, wondering at these difficult concepts. Just asking.

[@SergeiKotikov]

Your visualisations are fantastic. 3b1b grade stuff - very consistent and pleasant to look at.

[@ScienceClicEN]

Thank you very much that's quite a compliment !

[@aunumever]

This is the intro everyone needs and probably the best video I’ve ever watched. One that I will keep rewinding to understand.

[@PrasadNarse]

Simplifying the quantum theory with visual representation is an eye opener! Thanks so much for the simplified expressions!

[@audiblevideo]

I’ve been a casual pursuer of physics since my childhood when my science project was about black holes (back when they were only theoretical objects). This video combined with several other recent explanations have finally cemented a mental model in my head of our current understanding. Thank you VERY much for the explanation of spin. Too many people just hand wave it away. Having the Higgs particle/field explained as having a spin of zero makes sense for a lowest energy field that permeates all space. Sorry if my diction isn’t properly technical.

[@thedeemon]

Higgs field's spin is not related to its energy. It's spin zero because it's a scalar field, as opposed to vector fields of bosons like photons and W/Z/gluons, and spinor fields of fermions like electrons etc. On the opposite, it has much more energy than others: while for other fields their vacuum state is being at zero, no particles, no energy, in Higgs field its current vacuum state remains at a non-zero value everywhere, its vacuum expectation value. This non-zero value of Higgs field is what's giving mass to other particles.

[@audiblevideo]

@@thedeemon I understand that the Higgs field has a value everywhere. Is that number a positive or negative value, and does that matter? Is the Mexican hat dip above or below vacuum 0? Is this even a question that make sense? :) Having the field scalar makes sense. Thanks for your explanation.

[@thedeemon]

@@audiblevideo The scalar in Higgs field is a complex number, not a real one. Is i above or below zero? I guess you've seen that 3D mexican hat chart. It shows how the potential of the Higgs field depends on the value of the Higgs field, where the complex number value of the field serves as the horizontal 2D coordinates and the height of the hat at that point shows the potential. The center of the hat is the complex value of zero, the zero value of the Higgs field. It's a local maximum of the potential, so as you go away from zero in any direction the potential gets lower. At a certain radius it reaches a minimum and then starts growing again. That circle of points where the potential has that minimum is a set of values of Higgs field with the same absolute value but different phase. The current Higgs field value is believed to lie on that circle, but it can freely move along that circle. So we know the absolute value, but probably not the phase, not the angle where exactly on that circle the actual value lies. This shape of the potential means the Higgs field value can move/change in some directions (along the circle) without a change in potential, this gives us some massless Goldstone boson. A change in radial direction involves growth of the potential, it's like a potential well, a change in radial direction gives us a massive boson, the Higgs boson (an excitation of the Higgs field from its vacuum expectation value).

[@audiblevideo]

@@thedeemon thank you. I think I glossed over in my readings that the Higgs field represented a complex number. Complex numbers are VERY interesting. For anyone else here is a good run down of complex (imaginary) numbers kzbin.info/www/bejne/imeXaHZ9qNqCjLc

[@deepjyotiray2010]

@@audiblevideo but why is a physical field partially imaginary ?

[@0dWHOHWb0]

The production value is off the charts, man Once could've been a fluke, but I've seen enough good content here now that I have no choice but to subscribe

[@ScienceClicEN]

Ahah thanks, welcome !

[@Duffynez]

BY FAR THE BEST explanation of the QFD I have ever seen. Well done!

[@Kowzorz]

Phenomenal visuals and explanation. You opened a new understanding in my mind.

[@spacekettle2478]

"How is it, that an electron coming from the far reaches of the cosmos, has exactly the same mass or charge as an electron in an apple?" Mind. Blown.

[@elizabethwinsor5140]

Its the taste of the apple that should blow your mind - "How" does taste get into it and into "you" unless your a superposition of thems ....?

[@Skynet_the_AI]

@@elizabethwinsor5140 how: wow!

[@Geddyfleaharris]

I am not, nor even close, to being a physicist. I just like reading and watching KZbin videos about physics, relativity etc. But the 2 electrons being the same seemed logical to me. Along the lines of an electron is an electron is an electron. I have no scientific explanation to back that up. Just seemed intuitive to me.

[@yash1152]

reallyyyy?? to me, both are called same thing, "electron" in this case, because they have same properties. And 2 electrons - which by the name means that they have same property - WILL have same properties. if it had different properties, then they'd have different names lol. take how is anything named.... this is how it goes.

[@kashu7691]

@@yash1152 circular reasoning

[@serenityindeed]

Very nice, describing the roll of spin for various fields really helped build up my intuition. Thanks!

[@Colony28]

Wow! This is so accessible, beautiful, and simple to follow. I totally love it.

[@isaac.zeitgeist]

the way you just summarized all possible electron-electron interactions to give as a result what we observer as repulsion is just... magic congrats on the video, seriously, you have a new subscriber

[@paulgoodwin8840]

This is hands down the best explanation for QFT I've ever seen.

[@extinnocence]

My minds been blown. I've been wondering about these things for years and could never get a clear visual, and you've done it kind sir.

[@davidsansom2553]

Outstanding, the best explanation of fields, classical and quantum, symmetries, and spin I have ever encountered. I love your videos on General Relativity. Kudos to you 😊

[@thegreatreverendx]

This is the clearest, most lucid explanation of anything regarding quantum mechanics or particle physics I’ve ever seen. If all physics classes can be taught like this, I imagine we’d have a lot more working physicists.

[@Rationalific]

1:46 - "In this video, we build together Quantum Field Theory". "Hell, yeah!" In the end, I think you put in a lot more work than I did on this venture... In fact, WOW! I don't know what is more astounding...the quantum world or that such a deep yet understandable and visually compelling video could be produced. Amazing job to those involved!

[@lucas_liano]

This is absolutely awesome! The animations are super clear and the explanation is so good that you dont need to know much math to understand the concept below it. Super glad you made this!

[@willcollins9470]

I've been watching videos for five years on this stuff. finally it is all in one place. thanks

[@tommychobo3537]

The visualizations are amazing and super helpful!

[@ph6560]

Woow, Alessandro is good! These physics visualisations and explanations are - without exaggeration - some of the best I've seen on youtube. Please keep making more!

[@ScienceClicEN]

Thank you very much ! I will ;)

[@gerardjacquemier5137]

Very remarkable video, both for its content, explained in a perfectly clear manner, and for its esthetic qualities

[@juanrincon777]

This is absolutely incredible work. Thank you for making this.

[@andriy6485]

Absolutely astonishing elegance that just morphs it into near- or true perfection of introductory explanation of QFT.

[@kieferonline]

Hats off to the creator of this video. Really good script and excellent visuals!

[@davidroberts6909]

This is spectacular. The pauses are great, giving a chance to let it sink in the mind. Your visuals and script work tremendously well. I only now have a better idea of spin due to your work.

[@lemonblue6282]

This video is a trip. Thank you. I know no one would ever say its what I'm actually seeing - because we're talking about things only seen with electron microscopes and other such equipment - but I've had my eyes examined for years by different specialists - and this video sounds most like what I see and have seen since the early 90s.