The Hydrogen Atom, Part 1 of 3: Intro to Quantum Physics

The first of a three-part adventure into the Hydrogen Atom. I'm uploading these in three parts, so that I can include your feedback in the videos as we go along. Sort of like in a lecture when they stop and ask "Does anyone have any questions?". So please let me know if you have questions! :)

Part 2 will solve the Schrodinger equation, deriving the energy eigenstates and eigenvalues. Then we'll look at the hydrogen spectrum and see how these ideas make contact with experiment.

Part 3 will go beyond Schrodinger, exploring how the Dirac equation relates to hydrogen and provides a natural explanation for spin (and a nice prediction of antimatter, too), and then we'll look at the Lamb shift and talk briefly about quantum electrodynamics.

Chapters:
0:00 Intro
1:34 Why doesn't the electron fall in?
3:20 Proton is Massive and Tiny
4:20 Spherical Coordinate System
5:24 Defining psi, rho, and hbar
6:53 But what do the electron do? (Schrodinger Eq.)
9:37 Eigenstuff
11:45 Constructing the Hamiltonian
16:18 Setting up the 3D P.D.E. for psi

#physics #quantum #math

[OLApplin]

3:36 "The difference in mass between a proton and an electron is the difference between an elephant and 1836 elephant"
Thanks for this insightful comparison

[johnsjarboe]

Really like the approachability that you deliver the concepts while also not shying away from the math. I think there's a gap in the physics education space these videos fill.

[haakoflo]

"Have you ever tried to catch a quantum particle?"

Yes, every time a photon hits my retinas.

[rq]

We're going to be great friends. The low key elephant humor, the quick explanation of every symbol used, not shying away from reality or confusion. This is a great explanation and I will watch the sequels as soon as they drop.

[RichBehiel]

Hi everyone, thanks for checking out this video! :) Please let me know if you have any questions or suggestions. I'm still cooking up parts 2 and 3, so I'm hoping to modify those based on your feedback.

Edit: lots of great responses so far, thanks everyone! A few of you pointed out that the transitions between 100, 200, and 210 are more complicated than I’ve shown here, and you’re totally right, when thinking about angular momentum and such there’s more nuance involved than just shooting any old photon at the atom. We’ll talk more about that in the next video :)

[CHp-uptx]

man, even though there are so many mathematical concepts that I don't understand, somehow I managed to intuitively understand each step to get to the final product, you left me breathless. Freaking amazing!!!

[quantumeveryone]

Just a couple of points about your video, since you asked for suggestions: (1) The 1s to 2s transition is a forbidden transition, so it requires two photons to have it work, not one as you illustrate (1s to 2p is fine and 2p lives in the excited state about a billion times less long). This plays an important role in the Lamb shift experiment and in the proton charge radius experiment. (2) You seem to be using an ontic viewpoint of the wavefunctions, as if the electron is the wavefunction. Some people do use this picture, but it can have a lot of issues with interpretations of quantum phenomena. It might be useful to explain these issues. (3) I am not sure if this is your first discussion of kinetic energy as a Laplacian, but because for waves on a string, the second spatial derivative is the potential energy, some additional discussion of why it changes for quantum mechanics might be helpful to your audience.

[jamesbentonticer]

Your delivery is so listenable and you sound like you are having fun explaining this to us. Easy to be motivated with your instructor is enthusiastic. I hope you continue to make more content. It is of great value to anyone looking to better understand bed-rock reality.

[thecaribbeanbookworm]

This is perfection. After having finished my first quantum course (working up to the hydrogen atom), I found some of the later material as explained in the Griffith’s book to not be so intuitive (especially on 3D wave functions). So this is a really nice bridge between intuitive clarity and rigor, as others have mentioned. Thank you for the awesome content!

[mayonakao]

You did an incredible job explaining it. Thank you for helping the world’s future students. I read my textbooks for QM front to back many times, and this video was the first I’ve seen to teach by intuition instead of ”hope you learned linear algebra and statistics”

[michaelblankenau]

Beautiful presentation ! You not only have a deep understanding of the subject but also know how to make it accessible. Congratulations.

[musequal]

Really glad I found your channel, love to hear the enthusiasm in your voice! I feel the same way about physics, very late to the show, but I'm kind of hooked now. There's always a little Eureka moment when I try to extrapolate on what I'm learning and then have it confirmed or fail, which leads to more learning. Something very Promethean about it, music synthesis really gave me a lot of insight into wave forms, helps visualize the math and make it fractionally less daunting!

[-justasoul]

Your videos are just amazing! ❤And you radiate such positive energy in your explanations, it's a pleasure to listen. Can't wait for part 2 and 3.

[Verrisin]

This is so much more clear than anything on this subject I've ever seen!

[vtrandal]

Absolutely wonderful. The YouTube algorithm is timely in its recommendation of this video to me.

[drmarioguti]

Awesome video! I appreciate your effort to communicate this knowledge. I can't wait to see parts 2 and 3. I have no suggestions. This is just perfectly illustrated to me. Thank you.

[turel]

This video is fire! I think it's one of the best resources out there for learning and understanding quantum physics.

In my opinion, there are three main aspects to learning: knowledge, understanding, and motivation. We know that 2 + 2 is four, but unless we understand how addition works, we won't be able to solve 2 + 2 + 2 on our own. And without motivation, learning becomes challenging.

I particularly enjoyed the beginning of this video. The excellent animation made me contemplate how atoms truly behave and why. It sparked my curiosity and motivated me to learn more.

Your video has fantastic visuals that help us grasp the concepts, and your explanations are well-timed, clarifying everything effectively.

I liked everything about this video, but I do feel that its length wasn't sufficient. However, it's great that you made it that long, as it doesn't intimidate viewers. It also provides breaks and leaves us eagerly anticipating part two.

What I would suggest is creating separate videos. I would love to learn more about how quantum physics developed since it's complete beginning. How did Schrödinger derive his equation? Why do we use Hamiltonians? It would be wonderful to see examples of their use. For instance, pose a simple question and provide a solution using the Hamiltonian.

[kgblankinship]

Very clear and intuitive exposition. His presentation reflects a very clear understanding.

[luislab]

Probably the best video on the Quantum Mechanics of a Hydrogen Atom I have seen so far. The animations are great.

[prabeshbashyal]

I am actually impressed and excited by the way you are explaining things. Just excitedd for the next parts! <3