Quantum field theory, Lecture 1

[@accountone8315]

0:00 (Skip) 5:00 Sources and Textbooks 11:03 Outline 14:21 Notations and conventions 16:10 Theory of Everything: our higher goal 32:00 Relativistic quantum (field) theory 35:44 Poincaré group 42:55 Lorentz transformations 45:12 Poincaré group (it's a group) 49:11 Product between Poincaré transformations 54:24 Unitary and antiunitary operators

[@garyhamilton2104]

Thanks I appreciate you saving me 11 minutes

[@ChaineYTXF]

You, sir, are a gentleman and a scholar. Thanks

[@charbeleid193]

You are doing god's work

[@DarthCalculus]

Don't know why lectures on KZbin are more enjoyable than in a classroom. Maybe less pressure. Great teaching!

[@realitynowassigned]

Easier to take notes

[@kierahicks9314]

But I need subtitle 🥺😔

[@homeape.]

its the x1.5 speed button, isnt it?

[@SohailSiadat]

Maybe because you can relax on sofa or lay down? Also just knowing you can rewind whenever needed, gives the watcher a piece of mind.

[@ChaineYTXF]

@@homeape. most certainly is😁

[@CaliforniaMISC]

actual lecture starts at 14:00

[@antoniolewis1016]

Thanks

[@youteubakount4449]

mvp

[@gastonbarboza3568]

THANK YOU

[@oregondude9411]

CaliforniaMISC VIP right here

[@TheDavidlloydjones]

Even then, it never really gets going. We spend something around 50~60% of the time watching his back as he writes notes on the board. This is very odd since he obviously knew beforehand what he was going to write. Why not put them on screen as graphics, perhaps with him sitting at a desk or something at the side of the screen?

[@debajyotisg]

These series of lectures is the perfect combination of board work, information, intuition and all other things that make a lecture series great.

[@lebecccomputer287]

0:00- course breakdown/university credits 14:00- notation and units 17:00- the most satisfying chalk board eraser you’ve ever seen ...to be continued

[@tomasmanriquezvalenzuela5909]

First lecture: ~127 000 views Second lecture: ~ 33 000 views ... Last lecture: ~5 500 views It's like Javier Garcia's general relativity course, first chapter ~200 000 views, but last chapter just ~7 000

[@pelimies1818]

I believe this is the reality with Susskinds lectures on QM, QEntangelment, etc. When it gets to those greek letters with more greek letters in sub/super indices, there is nothing to see/hear that makes ANY sense for casual KZbinr, without few years of actually studying the field - starting all the way from classical physics and the basics of mathematics. There is no way to skip and start here.

[@aguuaaa]

welcome to the first class. first thing first: lenght = time = energy ^-1 = mass^-1 D:

[@hisohambanerjee]

aguuaaa that's natural unit, look it up.

[@Lord-V15]

It was at this point (and some quantum mechanics lectures) that I realised I'd never be a great physicist. Good luck to everyone continuing in the field. I wish you the best.

[@kevindenotaris]

When you defined a Group, you forgot to mention the associativity!

[@tobiasjosborne]

Oops; thankyou for noticing that! I didn't plan to get into the definition of groups in the lecture but then it seemed natural to do so on the spot and I did it from memory without preparing... Do check out the correct definition: en.wikipedia.org/wiki/Group_(mathematics) Sincerely, Tobias

[@sergeyliflandsky3231]

Regarding 59:04, separability of the Hilbert space space means that there exists a dense countable subset. There is a theorem that says that for a separable Hilbert space there exists a basis , which means that there also exists an orthonormal basis which is a very much desired property for the framework of quantum mechanics.

[@tobiasjosborne]

I am aware of this theorem. In particular, separability implies the existence of a countable basis, which is convenient. The question I am interested in is this: is the requirement of the existence of a *countable* basis fundamentally required to do quantum mechanics, or merely convenient? Sincerely, Tobias Osborne

[@sergeyliflandsky3231]

@@tobiasjosborne The whole point of countable dense subset is to ensure the existence of a countable basis ,because every Hilbert space has an orthonormal basis, it can be shown by invoking Zorn's lemma. Intuitively it seems to me that separability should be required. Because if you build a general framework with a bizarre Hilbert space which doesn't have a countable basis, it is very hard to imagine how this theory will reduce to the non relativistic quantum mechanics where all the operators have eigenvectors which form a countable basis for the space. Maybe at the limit it will project to this nice space? But then it would mean that an uncountable infinity of dimensions disappear suddenly in the limiting process. It is far from being a proof but it seems reasonable to me that this should be required unless all approaches that make this requirement fail miserably.

[@tobiasjosborne]

@@sergeyliflandsky3231 Indeed I am more than aware of the implications of separability. The point of the question is exactly this: is it *fundamentally* required that Hilbert spaces are separable in order to do physics. To be clear: I am not satisfied with any argument of the form "it is very hard to imagine ...", as this could simply mean we need to wait for some clever person to show how to do it. I am interested in whether it is possible to prove, *rigourously*, that non-separable Hilbert spaces, cannot be useful for physics. There are precedents for very interesting proofs of impossibility in physics (see, e.g., Bell's theorem). The background of this question is the following: I am led to understand that non-separable Hilbert spaces arise naturally in loop quantum gravity. For this reason loop quantum gravity has received criticism. But, as far as I am aware, all the criticism so far has been of the form "it is very hard to imagine ...". This criticism seems poorly founded: while I am no expert in loop quantum gravity, it seems they are nevertheless able to work with these spaces. Sincerely, Tobias Osborne

[@sergeyliflandsky3231]

@@tobiasjosborne I didn't mean to imply that you are unaware of the implications, but in the lecture you just said that it is a technical condition which might be unnecessary , without elaborating on it or saying that it guaranties a countable basis for the space like in the non-relativistic QM. I remarked it because I thought it might be beneficial to some of the viewers. I wasn't aware that in any domain in physics unseparable Hilbert space might arise naturally. This is really interesting. From all I've seen even in mathematics unseparable Hilbert spaces are more often referred to as exotic counterexamples rather than the main object of interest or study. As to a rigorous proof of the statement its is probably un-provable that such a space is useless , because you can always think of this nice useful space as a subspace of the complicated space, and the extra dimensions can be given some meaning.

[@saikopatu]

I've seen and TA'd several QFT lectures in different form, but I really like your approach and will watch the whole series. Also, your jokes are hilarious. Your students must be really unfunny because I don't hear anyone laughing :D

[@shashankchandra1068]

What composition creates a 'quantum field' ? Is a single quantum field a composition of 'n' number of same particles concentrated in certain 3D space around the universe or is 'quantum field' an energy concentrated in certain 3D space around the universe? Example: is up quark-quantum field nothing but 'n' number of up quarks concentrated in certain 3D spaces around the universe and if tht particle elevates above/forward to that 3D region then it's called exictation ORRR is quantum field some type of energy(some liquid or plasma kind of) and excitations of that field is a spherical elementary particle example:QUARKS

[@qewqeqeqwew3977]

Transformation with shift added to rotation isn't linear but affine. Anyway, very clean introduction, enjoyable to watch.

[@tobiasjosborne]

oops, thanks for catching that! Sincerely, Tobias

[@StinkingKevin]

I love this guy. I lecture in physiology, and I'm not bad. This guy is young, and he's making me get it. He's excellent. Fuck, yes.

[@17zty]

Thank you very much for spreading the knowledge, I missed the QFT course in my school and I am glad I can catch up here!

[@Kelvin-ed6ce]

what mathematical prerequisites are needed for a course like this? Thank you.

[@tobiasjosborne]

I would recommend: (a) Linear algebra and (b) calculus. A little functional analysis (e.g., hilbert space, banach space, topological vector spaces) can help a lot. Sincerely, Tobias Osborne

[@Bored14690]

I have a question. The Poincare transform (\Lambda,a) was a transition function between coordinate patches on a 4-manifold M that models space-time. Now, the unitary operator is a linear transform from a Hilbert space H to itself. What does it even mean to find a unitary operator for a Poincare transform (in particular one where the transform is the operator)? Is H=M in this case or H is the fiber to the infinite dimensional vector bundle whose base is the manifold M?

[@abdelrahmanabusiam2792]

I have the same question, I agree at a first sight it does not make sense for the operator to be the transform itself for the reasons you mentioned, did you find an answer?

[@Bored14690]

Hi @@abdelrahmanabusiam2792 . I terribly misunderstood how (where) these transformations work. A reasonable knowledge of special relativity is required to get here. I recently watched through lectures (kzbin.info/www/bejne/n3ekqYZ7pM9pfdE) to understand what are Lorentz transformations rigorously. I've not read through many sources, but such a clear description is rare.

[@corbin_parker1003]

Maybe matter is just a form of relative energy but that’s kind of similar to string theory.

[@peterwildemann6375]

Very concise and clear introduction; I'm in particular thankful for the word on possible phase factors in the Poincare-representations, since it seems that this is most often ignored, although the whole spinor-theory rests on the fact, that we allow just this! What I missed was a word on what it means (from a mathematical point of view) to be a single-particle theory. Can you point out any references regarding this?

[@tobiasjosborne]

I would recommend Bratteli and Robinson volume 2 for a discussion of single-particle/many particle theories at a mathematical level. Best wishes! Sincerely, Tobias

[@ANSIcode]

Does anyone happen to know which videos by Arkani-Hamed concerning natural unit systems are referred to at 15:10? I don't seem to be able to find them.

[@tobiasjosborne]

Dear ANSIcode, Many thanks for your comment! The videos I'm referring to are kzbin.info/www/bejne/pIeyZXxpeZhrhZI in which Arkani-Hamed gives a fantastic introduction to natural units, amongst other things. Sincerely, Tobias

[@AyaAboulella]

Apparently the comment isn't complete .. what're the videos again?

[@tobiasjosborne]

Dear Aya, Here is the link I was referring to: kzbin.info/www/bejne/pIeyZXxpeZhrhZI Sincerely, Tobias

[@Happyusle]

Hello, question: We say that we are scared from the fact that there are not any non trivial FINITE dimensional unitary representations of the Poincare group. And I am OK with it, I can believe it. But why would we even care about FINITE unitary representations of P+? We are searching for a representation U: H - >H, and since H is always infinite dimensional in the cases we are interested in (here I might be wrong) we shouldn't even care about finite representations. And thus we should not be scared from the fact that we cannot find any, simply because we don't need them. Thanks for the good lecture btw!

[@tobiasjosborne]

This is a fair point. I guess I would say that one reason to care about finite-dimensional representations would be so that we could make exact lattice discretisations. It would have been very convenient if we could have finite lattice models of relativistic quantum fields. Nature doesn't want this though: we can't discretise without breaking Lorentz boosts. I hope this explains my comment. Sincerely, Tobias Osborne

[@vinitchauhan973]

Keep up the great work :) im currently reading "An Introduction to Quantum Field Theory" by Shroeder and peskin, great book In my opinion

[@dawnwatching6382]

Just curious, how come this course is in English and the other ones are usually in German? Is there an expat program in the university? Great lecture, thanks for sharing!

[@tobiasjosborne]

This lecture is also part of our MSc programme, which is available entirely in english.

[@pierrevandwalle18]

Can't we just store the average data, or the refined data? Which obviate the need for infinite storage.

[@lordlight1124]

I think quantum field theory, chromodynamics, and quantum electrodynamics is best place to start when learning about computers. You need a solid fundamentals

[@Toxoplasmosic]

Babies should learn it in their first semester if they want to have any chance to walk IMHO

[@Joao-uj9km]

What a spectacular lecture 😮

[@marionascimento450]

Do you recommend any sources (videos, lecture notes, textbooks) for basic quantum mechanics, as basis for your advanced QT and then QFT?

[@tobiasjosborne]

I quite like Peres' book on QM. Also Griffiths is good. I also read Shankar's book and thought it covered a lot of useful stuff. I hope this helps; sincerely, Tobias Osborne

[@marionascimento450]

@@tobiasjosborne Thank you very much.

[@mobiusknot2949]

Hi +Tobias, Thanks for this clear lecture! However, I did not understand the last part of the lecture, the argument and the thought experiment for tension between *locality* & *interaction.* If you're gonna answer them in the following lectures, then, please ignore them, but could you please let me know!Thanks Do you mean *measuring* the particle's position ends up having a system with higher energy and then this particle creates particles(I assume from vacuum you meant)? Otherwise, a point particle is local in space-(time?). Is not it? We write location of(particle)=(x,y,z) which means a point in space. Also, how is it relevant to the *dimension* of *Hilbert* *space,* then? Thanks again!

[@prasadpawar7027]

1:16:40 Is there any reason to assume that V(t) evolves through Schrodinger equation?

[@moorg745]

This is not an assumption. This is the form that time evolution operators take in quantum mechanics. V(t) is simply a time evolution operator.

[@prasadpawar7027]

@@moorg745 Okay. I know that it takes that form in QM but wasn't sure here. Thanks.

[@mirijason]

Great lecture! I just have one question though about the positive energy condition 1:17:54 of the Hamiltonian and I hope you (or someone) will be able to answer it. Let's suppose the universe is a closed system that is described by quantum mechanics. Then every measuring device would be described by the Schrödinger equation. Say I was able to solve it exactly (interactions and all). Then I would know the eigenstates of the Hamiltonian and these would all evolve independently just by a phase shift $\exp(-i\omega t)$. Then whatever the spectrum of H, the universe cannot decay from one eigenstate to another. Hence it shouldn't matter that the hamiltonian is bounded or not from below. The way I understand it is that it is only a problem if I am doing perturbation theory starting from an unbounded hamiltonian that I know how to solve and add interaction terms from there. But if I know how to solve the exact hamiltonian then the state of the universe could be decomposed onto energy eigenstates and each would just evolve with a phase without ever changing into other states right? PS : and a second note - Even if my starting hamiltonian in perturbation theory is unbounded, there could exist conservation laws that would be able to prevent infinite cascading such as an electron cannot disappear and turn into a photon or whatever due to charge conservation for instance. So maybe requiring the hamiltonian to be bounded from below is not necessary after all? Just that we need to deal with all the interaction terms present non-perturbatively. I acknowledge that it may be extremely hard or even impossible to do but I believe there is a difference between our (in)ability to solve problems and the existence of solutions to them (for instance some polynomial equations of degree higher than 4 are impossible to solve using radicals although there exists solutions).

[@rushunnhfernandes]

2 years have passed... And I can only wonder if you have the answer to your question now?

[@mirijason]

@@rushunnhfernandes I didn't even remember asking that question hère 😅 although I still believe what I wrote back then... Though I didn't give it much thoughts lately.

[@rushunnhfernandes]

@@mirijason 😅... Have you completed ur studies though?

[@mirijason]

@@rushunnhfernandes yes, I already had my PhD in physics since 2017 but I didn't study quantum mechanics that much. And since I started working, I don't have that much time for side work like such so...

[@rushunnhfernandes]

@@mirijason congrats doctor 👏👏

[@fawzyhegab]

The lecture suggest that in some cases, getting a representation of a group enables us to solve differential equations (e.g. projective unitary representation of of Poincare group solves Schrodinger's equation and more). I wonder, could you please tell me the mathematical topic under which such an idea is exploited? Could you recommend a reference to know more about this idea (especially, for mathematical point of view)? Maybe other examples for such phenomenon with other groups and other differential equations?

[@tobiasjosborne]

I'd recommend any book on the representation theory of lie groups; they should all give a discussion of this idea. Sincerely, Tobias Osborne

[@tiamatbenoit7267]

@@tobiasjosborne Read representation theory by Fulton and Harris

[@mart_of_chaos]

The question is: Where the water from the board goes after washing?

[@saaman210]

15 years old, in 10th grade, completely devastated and confused by the math involved

[@crabcrab2024]

First you are afraid, you hate this stuff, then you get used to it, then you start to understand it and finally it’s a new normal.

[@MrEiht]

Amazing stuff. Anyone else watch these in the background while gaming?

[@the145kinga]

LMAO 😂 I am watching it while auditing ..

[@MrEiht]

@@jiaruizhao8683 why? Cause Wall Street will make you cash money? You can trade and do physicx.

[@jiaruizhao8683]

@@MrEihtHi! im just kidding QFT is too hard. this video is really good and im watching it feeling very good now!

[@MrEiht]

@@jiaruizhao8683 glad to hear that king. Just because its hard its more desirable to master. GL&HF!!!

[@ResetToZero3210]

Best part is the cleaning of the blackboard…😂

[@int_fx_dx]

Thanks for sharing these lectures! I find them very coherent. I think you probably already know this book, but just in case let me recommend to you a beautiful book by Michele Maggiore "Modern Introduction to QFT", I think it fits your corse very well.

[@tobiasjosborne]

Thankyou for the book suggestion: I am not familiar with the book and will check it out. Sincerely, Tobias Osborne

[@gurukalyan3145]

Dear Prof. Osborne, Great lecture! Could you direct to a more detailed discussion as to why locality only works in a many particle theory and requires a field to encompass it? The gedanken expt at the end is nice but I was hoping for something more mathematical if possible. Thanks in advance!

[@tobiasjosborne]

Many thanks for your comment. Unfortunately I don't really have any better explanation nor do I know of any more mathematical references. It is a bit hard to discuss this point more precisely without defining QFT more precisely (which is mathematically challenging). Maybe you might be interested in algebraic quantum field theory (AQFT) where locality plays a key role. I hope this helps. Sincerely, Tobias Osborne

[@gurukalyan3145]

Thank you Professor. I’ll check that out.

[@samferrer]

Why do we must have a theory of everything? Why it is not sufficient a theory for each big thing?

[@sidddddddddddddd]

Hey professor, can we directly come to this course from your Advanced Quantum Theory or you recommend to do your Symplectic Geometry and Classical Mechanics course first? And if yes, where exactly does the Symplectic Geometry and Classical Mechanics course lie? Before this or along this course?

[@tobiasjosborne]

The symplectic geometry course is completely independent and you can easily watch QFT after adv. q. theory. sincerely, Tobias Osborne

[@αλ-ΧΗΜΕΙΑ]

Great Lecture for a QFT intro ! I would like to ask one question, The "one parameter family of unitaries V" are operators, so how do they solve the Schroedinger's equation? Are they "wavefuctions" of a kind that are acted as operators? Thanks in advance, Teo

[@tobiasjosborne]

The unitaries are operators (also sometimes known as "propagators") which take the initial wavefunction at t=0 to the wavefunction which is the solution of the Schroedinger equation at t.

[@weibu8272]

Is the content of your lecture similar with the book written by Steven Weinberg?

[@tobiasjosborne]

Dear Wei Bu, Many thanks for your comment. Some of the lectures are inspired by Weinberg's books but it is most similar to the lecture notes of David Tong. Best wishes! Sincerely, Tobias

[@areciboKCK]

Can anybody here post a link to those Nima Arkani-Hamed videos Tobias mentions?

[@malikadaif7991]

من فضلكم كيف اترجم الفيديو الئ العربية؟

[@davidwilfand916]

Thank you so much for these lectures! I would love to know what are the prerequisites for this course?

[@tobiasjosborne]

Dear David, I would strongly recommend a basic quantum mechanics course and then, after that, watching my advanced QM course videos kzbin.info/aero/PLDfPUNusx1Eo60qx3Od2KLUL4b7VDPo9F That ought to be sufficient. Sincerely, Tobias Osborne

[@bennymarshall1320]

Ooh, real physics, get you!

[@pmerel]

His apartment must be very clean!

[@ryanlyle9201]

Came for the science. Stayed for the board wiping.

[@ngdnhtien]

haha in my country it takes centuries for teachers to wipe their boards

[@bennymarshall1320]

'What is a group? I'll let you google this'. Well that was £7000 well spent

[@vishalrao7010]

amazing lecture!

[@m.e.345]

I always wondered where those squeegee kids got their training.

[@fawzyhegab]

Could you recommend a reference to dealing with angular momentum as looking for a representation for rotations?

[@tobiasjosborne]

I'd recommend something like www.staff.science.uu.nl/~hooft101/lectures/lieg.html . Sincerely, Tobias Osborne

[@Snuggy47]

We got this course already during our undergraduate (bachelors, is that the word?) education. We had courses in our first two years on mathematical courses like linear algebra, calculus, etc. Then we had two courses in QM, a course in SR, statistical physics and so on. However I cannot think otherwise while writing this at fucking 4am in the morning that I have not have the proper mathematical background knowledge to do this course with the same ease as the other courses so far. I was wondering how to approach this. I have an exam comming up, but I fail to fully grasp the mathematical manipulations you constantly need to apply, it seems so fucking random. I cannot even get to appreciating the field theory because all the time I am figuring out how to write shit down rather than solving a physics problem. I know that the math part is a inneviteble part of this field of science since... well, I dare anyone to intrinsically understand this to the extent to explain it without considering the math, but I cannot help to get stuck at this tensor calculus stuff. Does anyone have any tips on how to improve my intuition regarding this matter? What were your tricks and what are your tips to understand the tensor algebra part such that I can actually solve questions and more importantly actually understand it. Tong's book is a very good one but does not cover any of what mathematically is going on. Everything kind of happens without some background or justification. Or I am just stupido?

[@Auiofthebanjo]

Do you have an opinion on "Quantum Field Theory and the Standard Model" by Matthew D. Schwartz as a textbook on the subject?

[@tobiasjosborne]

Dear Robert, Many thanks for your comment! I am not familiar with the book, but I took a quick look: there seems to be a nice mix of topics. For my taste I'd have liked to have seen more on the Wilsonian view of QFTs as effective theories. However, especially interesting, is how efficiently the subjects are arranged in the book-it seems that you can get to the standard model via this text reasonably rapidly. Sincerely, Tobias Osborne

[@yousrazaa1269]

merci

[@kyungtaekim2185]

Thank you so much

[@nurlatifahmohdnor8939]

pa-dang = field pe-dang = sword pin-dang = about egg pan-dang = look

[@rafaelbendavid4041]

shouldnt the most important quantum system be the Universe?

[@cjellichheissen2379]

great lecture, the handwriting is hard to identify though

[@gunnardicken3844]

Nice lecture, but is the transformation really linear? looks affine to me. sorry if this sounds pedantic, but you point out that the constant term is important.

[@tobiasjosborne]

oops! good point, many thanks for the correction. Sincerely, Tobias Osborne

[@gunnardicken3844]

@@tobiasjosborne Thank you so much for this wonderful lecture!

[@sherrysyed]

Excellent! I didn’t understand the physics and math parts but I really enjoyed this lecture!

[@rediban]

Guten Tag Prof. Osborne, vielen Dank für diese hervorragende Videoreihe! Sie hilft mir sehr dabei mich weiterzubilden. Könnten Sie mir jedoch evtl. verraten was der genaue Name Ihres Audioeingabegeräts (Mikrofon) ist? Die Qualität ist spitze und evtl. würde ich mir das abschauen! VIelen Dank

[@tobiasjosborne]

Vielen Dank für Ihre Email. Ich verwende das "Rode Lavalier" und Zoom H1: www.thomann.de/gb/rode_lavalier.htm www.thomann.de/de/zoom_h1n.htm Mit freundlichen Grüßen Tobias Osborne

[@yu-chengtu8255]

Question at 1:16:10 . Can I say that is a one-parameter group of diffeomorphism ?

[@tobiasjosborne]

yes Sincerely, Tobias

[@yu-chengtu8255]

Tobias Osborne Thank you for answer my question! It’s help me a lot.

[@physicsmajor23]

The way the professor erases the board is oddly satisfying.

[@brandolumba7116]

These people are from another planet.

[@ladyboboful]

Brando Lumba Why do you think so?

[@aminr.544]

is this a masters course or a bachelors course ?

[@tobiasjosborne]

it is for both

[@cosmoshivani]

I really really want to start learning QFT but there is already so much I still don't understand... ●_●

[@Quantumroson]

In actual how many lectures are there???

[@wdlang06]

very grateful to you!

[@stevegandalf4739]

16:25 Why Quantum Field Theory ? ?? ??? ..... Think about why you want to know about QFT ..... 18:05 .... Quantum Field Theory is a Theory of Everything !!! ........ EVERYTHING :))) even including Postmodernism

[@frankdimeglio8216]

The crust of what IS the Moon is about TWICE as thick on it's far side !! The BULK DENSITY of what is the Moon is, in fact, comparable to that of (volcanic) basaltic lavas on THE EARTH/ground. The maria (Lunar “seas”) do occupy about ONE SIXTH of the surface area of what is the Moon. Almost ALL of this maria is on the near side of what is the Moon !! The surface gravity of the Moon is about ONE SIXTH of that compared to when that person is on what is THE EARTH/ground. The Moon is about one quarter the diameter of WHAT IS THE EARTH. About one third of the visible near side of the Moon consists of maria. The LAND surface area of what is THE EARTH is at 29 percent. This is EXACTLY between one third and one quarter. Great. WHAT IS E=MC2 is taken directly from F=ma, AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE); AS the rotation of WHAT IS THE MOON matches the revolution. Great. FACTS. Footprints on what is the Moon BASICALLY last indefinitely. NOW, consider what is the fully illuminated (AND setting/WHITE) MOON ON BALANCE; AND consider what is the ORANGE (AND setting) Sun. They are the the SAME SIZE as what is THE EYE. NOW, ONE HALF multiplied times one third IS one sixth. (Lava is about three times as dense as what is WATER.) CLEAR water comes from THE EYE ON BALANCE. THE EARTH IS ALSO BLUE. Notice what is the TRANSLUCENT AND BLUE sky ON BALANCE !!! Finally, notice that the curvature or shape of said/aforementioned MOON does match that of what is THE EARTH/ground (that is, given what is a clear horizon, of course). Magnificent. In other words, it is predictable, in fact, that what is the Moon is about ONE QUARTER of the diameter of WHAT IS THE EARTH ON BALANCE. BALANCE AND completeness go hand in hand. Importantly, what is gravity, ON BALANCE, is an INTERACTION that cannot be shielded or blocked. I have attained a gigantic breakthrough in physics. That is beyond dispute. Note: Lava IS orange, AND it is even blood red. Great. What is the orange (AND setting) Sun manifests or forms up at what is eye level/BODY HEIGHT. By Frank Martin DiMeglio

[@adrias818]

No offense here I just want to say it is extremely weird for me to see sincerely etc on youtube comments. Feel like we are back in the early days of Internet when people probably respected each other too much to the point of boredness.

[@Cajunflyer78]

Where are the captions for deaf people?

[@leonardodias3393]

Oh yeah Don't go anywhere else Be right here and wait for me I'll be back in one year or less i hope

[@emilsinclair4190]

...well it was more than 1 year. So how was it

[@leonardodias3393]

@@emilsinclair4190 LOL. I have personal issues in the pandemic. I have to change my careers goals and got into computation. Now, i'm studying to be a cybersecurity professional. I think that the field of cybersecurity forces you to know really well how things works (in the context of computation) so im still carrying my initial motivation that leads me to physics

[@jcollins8639]

Bruh… when do you get to the cool part? lol

[@jacobvandijk6525]

MY WINDOW CLEANER IS PAID WORSE THAN THE ONE IN THIS VIDEO.

[@pierrevandwalle18]

Is there irony in saying that a theory of everything is probably a quantum theory?

[@Hisham_Mubaideen]

thank you very very much

[@JArmandoValle]

so awesome!

[@jianhuiqiu158]

please add subtitles

[@abhishekms1059]

thank you

[@johncarlson7496]

College shouldn't be this slow

[@therookiegamer3755]

me who just read about electrostatics! :D

[@jlo3349]

david tong

[@homeape.]

lifehack: study in germany go to erasmus dont go to classes watch em from a german prof instead

[@sebas_7594]

I'm here just cuz I'm curious, and I dont understand all the math in here 😭, this is not for me i guess

[@saidlaaroua1178]

No doubt the lecturer and also people who watch this physics lessons are very clever, the cleverest people likely. However,this kind of lectures was appropriate for the 19th century. In the third-millennium education, videos should be displayed instead of asking students to imagine, discussions with students, some interaction with students.....etc,. If someone is to read loud from a paper s/he carries, well Personaly I prefer to read from a book

[@m.d.lu.m.d9292]

speed 1.5

[@chisuku]

This type of lecture raised more questions than it answered anything for me. Ideally, a lecture should start in a way that a person who doesn't understand anything will be able to follow along. This didn't happen here. I guess I am required to read or watch more BEFORE starting this lecture in the first place. Kind of disappointing.

[@emilsinclair4190]

...I mean this is how more advanced lectures work. If you always start at the beginning you don't have enough time to arrive at the new stuff

[@ox3424]

45:00

[@АлександрРусаков-в4с]

Hall Thomas Hall Gary Anderson Edward

[@Mohamedhgazy20]

👍♥️

[@laeequenadvi4746]

Mike Hunt PARTICLE PHYSICS IN HOLY QUR'AN The word " ذرة " used in this verse means itom. Smaller than itom indicate that there are particles smaller than itom.These were unknown till 19th century. New research says that itom is not single entity. It has many other particles inside like electron, proton, neutron and quark. These particles are smaller than itom. Almighty Allah says: و قال الذين كفروا لاتأتينا الساعة ، قل بلى وربى لتاتينكم علم الغيب لا يعزب عنه مثقال ذرة في السموات ولا في الأرض و لا اصغر من ذلك ولا أكبر إلا في كتب مبين o ( سبأ : ٣) Those who disbelieve say: The Hour will never come unto us. Say: Nay, by my Lord, but it is coming unto you surely. (He is) the knower of the Unseen. Not an itom's weight, or less than that or greater, escapeth Him in the heavens or in the earth, but it is in a clear Record". (Qur'an.Saba:3) Modern science knew this fact in 19th century. Who can say 1450 years ago that there are particles smaller than itom? Only Almighty Allah Who created these particles. Higs Boson particle is also created by Allah. It is not God. If yon see meaning of ذرة in Arabic dictionary you will come to know that this word means itom. It is written in all English-Arabic dictionaries. You don't know Arabic. Learn and study more. It is in your interest to believe in Almighty Allah and worship Him only and believe that prophet Muhammad is His last and final messenger. We believe in Jesus( pbuh) that he is prophet of Allah not God. Jesus never claimed the dignity. He was a Muslim and preached Islam as every prophet did from Adam to Prophet Mohammad(pbuh). Mohammad( pbuh) very clearly told his followers that he is a man like others but Allah choosed him and made him His last and final messenger. Muslims do not worship Mohammad but they worship Almighty Allah as prophet Mohammad ( pbuh) taught them. Jesus like Mohammad taught his followers to worship Allah only. The word father means the Lord. In Arabic He is called as رب( Lord)not God. Hope it is very clear now for every followers of prophet Jesus(pbuh) If we Muslims do not believe in Jesus as a prophet we are not Muslis and not acceptable to Almighty Allah. If a follower of JESUS wants to go in Paradise after death they should revert to Islam earliest possible and work as prophet Mohammad taught otherwise they may not enter into Paradise. Almighty Allah bless all of us. DR.MOHAMMAD LAEEQUE NADVI Ph.D. (Arabic Lit.) M.A. Arabic Lit.+Islamic Studies) Director Amena Institute of Islamic Studies & Analysis A Global & Universal Institute, Donate to promote this Institute SBI A/C30029616117 Kolkata,Park Circus Branch [e-mail] Thanks

[@antoniomantovani3147]

You are creazy for sure

[@MegaStrakk]

[@omarbriones2453]

Why would you spend time writing outlines (as in the first 16 minutes of the video) on the board? In my opinion, you should write that information before the class/lecture. It's a waste of your and the students' time to write that basic information during class time.

[@pasavant]

If he is English, why does he keep speaking and writing German? And why do they insist on using the metric system ?

[@jonathanansell1304]

why not just use powerpoint instead of writing and cleaning the board. seems like a waste of time and energy doing this by hand when everyone's sitting and watching you copy off a piece of paper.

[@lovelyloafers]

It's much easier to follow along when they write it out. It also allows the professor to pace the class more easily.

[@RalphDratman]

I'd say the prof incorporates the cleaning as part of the rhythm of his presentation. I like it.

[@carlosleiva]

This is not a social science lecture. Each step must be clear and the pace must allow to understand and copy.

[@Carofdoom1126]

Using a board is beyond common practice in mathematics and physics, it maintains lecture pace, forces the lecturer to enforce understanding and allows students to note down important info and follow along equation by equation in their notes if they wish. It works, and it works well. Every single powerpoint class I've taken in Physics or Math has been horrendous. In fact, I have a general rule of dropping a class if it's not nessesary for my degree, and its in the math or physics department, and I walk in and the professor is using a powerpoint to lecture. It is a very bady sign, and usually means the professor is a bad teacher.

[@Kelvin-ed6ce]

@@Carofdoom1126 exactly!!!

[@e4d578]

Nerds.