Відео

Tak!!

Grabbed my pen, notebook and completed half this lecture....I am just amazed to see and learn those interconnection....thank you very much❤

Everyone better watch this video in 0.75 playback speed. He talks so fast

🫷👁👄👁🫸 🦵 🦶 how my brain sees me after realizing that other brains be out here like :

Please bring back your Taylor Swift cover 😢

As I am revisiting these material, sometimes I am bit frustrated as to what details can be omitted, and what details are critical. For example, the Haidinger fringes, if two extended sources are separated by delta_z, then, using the same lens, they should not converge to the same point on the screen, but slightly offset due to delta_z, correct? is that because the extended source is very large compared to delta_z, so the offset is negligible? Then, when you show theta \approx r/f, isn't here r needs to be small compared to f for the approximation to be valid? I find it difficult to see how this approximation is making sense here, as the ring pattern is observed at a scale much larger than f. Then, at thin film interference, isn't that the derivation using wave formula assume the screen/lens to be horizontal, as the comparison is done at two refraction points rather than the two points on a line perpendicular to two rays, like the derivation using geometry? In addition, only the phase accumulation from z direction is counted for the ray travels in medium, but not accumulation in x direction, when the ray travels 2dtan(theta_2)? I tried to find answer to these questions in books and on internet, but no one seems to bother to mention. Hopefully someone can answer these questions, I fully understand that my understanding may be limited and my questions may be silly.

A hologram is not actually 2D. It is a 3D object with thickness which is required to create the hologram. Why is this not mentioned in any videos I can find on the subject?

Science instruction does not get better than this. I feel like I struck gold finding this channel. Superlatives do not even give justice to the crystal clear explanations that you give. Many thanks!

I think at 18:41, you shoud write the extra ∆P∆V which would then approximate to 0 when taking ∆P and ∆V as dP and dV.

I've watched like 20 videos on this topic, and this is the first time I understand the concept fully, and in under a minute, great stuff!

Excellent, and very much in the spirit of Griffiths or (the late mathematician) Harold Edwards. Was there an earlier version? I recall watching this more than a year ago. Really inspiring work!

I really enjoyed this video! It was a real delight to listen to the history of Physics and gain a deeper understanding of how the laws of physics were ascertained

Perfect. One comment about so-called the "collapse of Schrodinger function". Such talk@vocabulary is...poetry or psychologizing. The wave function exists in an "artificial-mathematical" phase space (as a complex plane). Still, it does predict the outcomes of experiments not with a "particle" but only with a stream (set, bunch) of them - by an analogy: a probabilistic formula predicts the outcome of every lottery: does it mean that Loterry machine "collapses" the probabilistic formula to get winning numbers? A nonsense talk!

@ 10:26 According to Hyperphysics (or better, the Department of Physics and Astronomy at Georgia State University) heat is the transfer of energy (like this: 23:07). Hanging on to this widely accepted definition, concepts like heat flow and heat energy tend to confuse people. It may even lead to a similar error like this: dU = dQ + dW. This is wrong because Q and W are already defined in terms of a change in energy. Thus, it should be: dU = Q + W. @ 13:27 Just switch the i and s irreversibly. @ 44:48 Nowadays, particle physicists want us to believe they can track the traces left by the unobservable Higgs boson. @ 47:54 And I like to add this advice: always be skeptical about what your read and hear in UA-cam-videos too. Simply accepting what you read and hear isn't very scientific.

Your channel is an absolute gem and criminally underrated. You clearly are a gifted educator and scientist. Wishing you millions of views and subs.

55:43 - - the soundwave of a certain b*tch. I know about them b*itches. Man your work is phenomenal, it's like a year's course in 2 hours.

OK not completely: at 17:50nn-the typical textbook nonsense on "time dilation". In the "Moving" system (x',t') these parameters x',t' represents not the values "recorded" by the moving "mythical observer=the set of synchronized clocks) but the ones as "been seen" by the observer in the system at rest! The "moving" observer records the same values of x',t' as the stationary observer,i.e., x,t; otherwise, it would violate the 1st Relativity Principle, then also that the unit time (of a clock) and distance (of a "rigid rod") is not "on2=1 sec,ore else)! Consequently, the case of "muon" (as a clock) is the same textbooks BS: a "muon" is a statistical "being=wave packet"; hence, all these experimental data can only be explained if one treats this "muon" as a "wave"; otherwise, the 1/3 of experiments data cannot be counted for -see the diagram for both radioactive "objects" at rest and "moving": in t>T(1/2-a halftime) the values of both functions are almost the same even graphically! One a better exposition of the Subject but not completely again

This is great! I tried to understand Heisenberg's magical paper for so long. This really helps! =)) THANK YOU SO MUCH, SIR

That was 🎉

I am totally in love with your work and content on youtube. You are providing something that many books fail to deliver, developing the subject in a chronological order. I just wanted to ask you that, will you be covering relativistic quantum mechanics and dirac equation anytime soon in future? eagerly waiting for your upcoming videos.

You have done great service to the small community of Physics Students who wonder How & where from was so much Linear Algebra & Operator theory was forced upon humanity in the Historical development, esp when we study QMech in the Modern way from J J Sakurai and the like... Thx a tonne!

Your work explaining the historical development of quantum mechanical models if fantastic and greatly appreciated. Thank you!

This answers so many questions I had about the transition from old quantum mechanics to current QM for so long!

Thx

18:56 Is S₃ supposed to have the signs reversed? It looks like it is supposed to be the Pauli Y matrix. EDIT: I should have watched to the end. I see you are already aware of the Pauli matrices.

Finally the wait is over!

I just come across your videos again and again and I can't understand how you're not a bigger name on youtube. Super good stuff!

This is outstanding. I have Stat Mech in the fall and when we get to black body radiation, I may take a day off and just run this video.

amazing

I enjoyed the video and thank you very much. I am trying to relearn all the things that I tried to learn in my university days from your great explanations. Thanks

Wow finally a video that actually SHOWS how it works, thank you 👍

I have always struggled with this topic, thank you for this very clear exposition. One thing that used to confuse me, was I thought that in the Carnot engine, gas had to flow from the hot to the cold reservoir. But from your video (and from considering a toy Stirling engine) it is clear that only heat needs to flow from the hot reservoir into the piston and then from the piston into the cold reservoir (with some of the heat energy converted into work). In many heat engines gas does flow from the hot to the cold reservoir but it is not necessary to consider for this analysis. The same amount of gas can remain in the piston throughout the cycle.

Great lecture, but why did you remove your cover of anti-hero?😢

Think you so much great work

Simply fantastic video! Thanky for sharing and well done!

Thank you so much for uploading all these videos. Some of them contain very unique ways to explain topics optics that you dont find elsewhere (on youtube at least). Your video about abberations is for example one of the cleanest ways to explain and differentiate the different terms I have come across. Very well done and thanks again! I got one question regarding the notation of polarisation (S- or P-Polarization or TE/TM) since you used it in this video in the chapter about fresnel equations: I regularly get confused by the TE / TM notation: It is used in electric engineering when describing modes in waveguides, it is used to describe modes in laser resonators (eg. TEM00).. Could you elaborate when we talk about S/P polarisation and when about TE / TM / TEM, and how to distinguish the terms properly? I have a feeling that TE/TM/TEM mean different things, depending on context. (Edit: in the end its the same question as in physics.stackexchange.com/questions/732802/te-and-tm-modes-vs-polarization )

@Sander thanks for your great video! I am trying to reproduce your results shown at @30:29 using python. However I am unsure how to do so. I did define a 2D array containing 9 point sources. However I am unsure how to then determine the diffraction patterns as shown in your image. Could you maybe explain your steps taken (or provide a part if your code)?

Brilliant video! Thanks!

This is so great I love it

Well written and produced

Sure, but compatibleism. My judgment here has nothing to do with morality, either. The brain is a physical object which evolves according to all relevant natural laws, so it is deterministic if physics is deterministic. But you _are_ your brain, and your brain is you; this is an observational fact. Your brain determines what you do, and you are your brain, therefore you determine what you do. End of story. That being said, my preference for determinism in physics is based instead on information and the principles of science. If the evolution of the universe dU/dt is not wholly a function of U then it must have additional parameters beyond U. There is literally not enough information in U(t) to calculate U(t+dt). But U is the state of the universe, which can only be defined as everything that exists, so if there's information outside of U, then we clearly aren't really talking about U. Furthermore, the basis of scientific reasoning is that we can infer functions of U by meticulously controlling and observing U itself, i.e. discover natural laws that apply at all t. If U does not include all of its own parameters, then it's no longer reasonable to use the scientific method to draw any general conclusions. The results of our experiments are contaminated with extra information that can never be interrogated out of U. We used the scientific method to discover quantum mechanics, so if this particular non-deterministic aspect of QM is true, then there is no reason to believe that QM is true. I choose to believe that truth can be known and science is valuable. Finally, determinism is restored by the Everett interpretation. You can have a deterministic view of QM so long as you acknowledge that you are a part of the wavefunction yourself, not some kind of magical god-like observer on the outside, beyond the influence of physics. The difficulty there is in fact the same mess that arises in free will when you assume dualism. Yes, of course the laws of physics apply to you, but that doesn't mean you are powerless, and it doesn't mean you have to twist your brain in knots with non-determinism.

Interestingly, in matlab2023b if you create the aperture with even number of pixels you do not have a linear phase, but you do with odd number of pixels. Opposite of what this video shows.

Great video!! Really complete. I've seen you have uploaded the pdf slides only for Heisenberg matrixes. Could you also upload the slides of the other videos? It could be useful to study them better. Anyway thanks for your effort! Regards Paolo Berra

At 13:09 , why did you ignore the 1/lambda*z term when you calculated the fresnel propagated field? And why didn't you take the abs^2 when presenting it?

This is great. Thank you!

@ 03:02 The comparison is a bit unfortunate. A classical wave function describes something physical, while the quantum mechanical wave function has no physical meaning. It's just a mathematical tool. @ 12:40 This picture (on the right) is NOT correct. No photon travels back in time. You should have used the picture on the left and changed the z-axis into a time-axis. Then, we're doing physics again. Read about "time-slicing", Sander.

@ 17:42 This is NOT a source-term. A real source-term is like the driving-force for a harmonic oscillator. But this "source-term" is the potential energy of that oscillator. There is no driving-force in this explanation; like there is no driving-force in QFT's. Quantum fluctuations have no physical explanation, only a mathematical one (the HUP). The famous Big Bang Theory has no starting point either; it is only an evolution theory. We have no clue where the initial impuls for The Big Bang or for quantum fluctuations comes from; IF these theories make any sense at all.

The name Snell (with double L) is an anglicisation of the Dutch name Snel (with single L). Anglicisation is like colonisation. You want to impose your own culture on everything :-(

@ 0:00 Here, he leaves out the QUANTUM MODEL of light. In video 9. he corrects this.