I forget whether it was Feynman to Wheeler or Wheeler to Feynman, but their suggestion was that the reason all electrons seemed so similar was that in fact there was only one electron in the universe. Wey-yul, I guess that would be one way of explaining it...
Yeah, see, an' E.O. Wilson says we don't need any bigger accelerators on account of the fact that for the next little while the progress in physics is going to be epistemological, not experimental. Looks to me like Wheeler and Feynman were on the same page with him on that.. If they weren't maybe a page or two ahead of him, that is.
This is at the perfect level of detail for me. I'd read this before (in one of Brian Cox and Jeff Forshaw's books) and had a vague understanding of it but couldn't recall exactly why it works. That book (forget the title) also coupled this with the uncertainty principle and then IIRC used the two ideas to explain how semiconductors work. My only comment is that it's hard to get through the audience comment parts because we can't hear what they're saying. Not a huge criticism, because otherwise this was perfect.
Hello. the frustrating part for me is related to the Pauli exclusion principle. You said 2 electrons with same spin cannot coexist on same orbital, it is "forbidden". Forbidden by who ? what ? Why would an electron "care" that something is forbidden ? How does an electron "know" that the other electron has spin up, then "decide" that it should have spin down, because "it is forbidden to do otherwise" ? that really makes no sens to me at all
I'm a little bit confused. You say that psi-squared represents the probability. You also mention that psi-squared is larger than psi. Now a probability is (by definition) less than 1. The square of a number less than 1 is SMALLER than the non-squared number. i.e. psi-squared should be smaller (not larger as you have shown) than psi. Can you please explain to me why you have shown the opposite of what should be happening?
The ratio of electric force and gravitational force between a proton and an electron is K e^2 / G memp ≅ 2.4 × 10^39. Q. Quantum mechanics doesn’t give the answer to the single most fundamental question: why electrons don’t collide with protons? Although, when it is applied to details it yields certain results… mathematically.
Heey Psrth! Good to see you! Long time no see, mate! 🤓 I can't hear the students, but it was hilarious when you said "that comes later. You are reading my thoughts, that's cool" 😆 So far so good, I'm in the indistinguishable part Commute! Commute! Good teacher indeed you are, Parth!
Wait but what if you swap 2 electrons in different orbitals and different spins. With the simplified math shown here both parts would have signs flip, and the wave functions would be identical before and after the switch which we just said wasn’t allowed for a system of 2 identical fermions. So there must be more. What’s missing?
What is the set of books with mathematical practice questions and that will make you expert-ish (gradually, if studied) in the field of quantum physics?
Linear Algebra and Differential Equations, especially those of the Sturm-Liouville type, are the two foundational mathematical branches applicable to Quantum Mechanics. An advanced text on Classical Mechanics that covers Hamiltonian and Lagrangian formulations uses concepts like Phase Space and operators.
In the example he discusses, the spins have to be opposite (different spin state) because the orbital states are the same. Ferromagnetic elements (Iron, Cobalt, Nickel, Gadolinium & Neodymium) and compounds are examples in which spins are aligned, but the orbital states are different. One can think of ferromagnetism as macroscopic quantum mechanics.
It ends at the principle of Being itself really, which can be said to be the structure of reality fundamentally. In Being, all particles find their relations and connections, because Being itself is connection and relation.
I really enjoy your channel, in fact I’m becoming a Patreon donor. I actually learned most of your content 40 years ago, in college. Yes, I’m old. However, I never used this type of content in my chosen field, professional Pilot. As such, I would like to ask a question, to check my understanding. The “wave packet” is the probability of finding the particle in that location. The wave packet is “semi localized “ in that the highest probability of finding the particle is in a fairly small region, but the “tails” of the wave packet trail off towards zero fairly quickly, but never actually ever reach zero. As such, there is very small probability that the particle can be found out by the orbit of Jupiter, however that probability is so vanishingly small as to be practically zero. Is that a correct understanding?
Am always astounded by how much you get so much praise and literal presentations because ya get bedazzled by already established and well explored properties... As if it was new or yours... All I could think was during that whole spiel was "antisymmetry" and outer products.. Also assuming you audience knows nothing, doesn't build a good presentation. Especially, when in fact the audience turns out, does know quite a bit. Unfortunately, the bystander effect (and vocabulary mismatches) takes hold of people answering well, much to the chagrin of presenters/teachers
I do not understand. Why does the “end justify the means” in this explanation? What is the mechanism keeping identical fermions from overlapping? If two identical fermions are on a collision course, how close do they get before that mechanism takes over, whatever it is? Assuming our current model is completely accurate, what *practically* keeps electron orbitals from all collapsing in to 1s?
![Digital Circus Episode 4 [TRAILER]](http://i.ytimg.com/vi/abZtsmMUbJo/mqdefault.jpg)
well done. A nice expansion over the Pauli exclusion principle, without which matter would not have volume hence, our universe!
I forget whether it was Feynman to Wheeler or Wheeler to Feynman, but their suggestion was that the reason all electrons seemed so similar was that in fact there was only one electron in the universe.
Wey-yul, I guess that would be one way of explaining it...
Yeah, see, an' E.O. Wilson says we don't need any bigger accelerators on account of the fact that for the next little while the progress in physics is going to be epistemological, not experimental. Looks to me like Wheeler and Feynman were on the same page with him on that..
If they weren't maybe a page or two ahead of him, that is.
This is at the perfect level of detail for me. I'd read this before (in one of Brian Cox and Jeff Forshaw's books) and had a vague understanding of it but couldn't recall exactly why it works. That book (forget the title) also coupled this with the uncertainty principle and then IIRC used the two ideas to explain how semiconductors work.
My only comment is that it's hard to get through the audience comment parts because we can't hear what they're saying. Not a huge criticism, because otherwise this was perfect.
Hello. the frustrating part for me is related to the Pauli exclusion principle. You said 2 electrons with same spin cannot coexist on same orbital, it is "forbidden". Forbidden by who ? what ? Why would an electron "care" that something is forbidden ? How does an electron "know" that the other electron has spin up, then "decide" that it should have spin down, because "it is forbidden to do otherwise" ? that really makes no sens to me at all
Could you please do a video on the Alcubierre drive???
I'm a little bit confused. You say that psi-squared represents the probability. You also mention that psi-squared is larger than psi. Now a probability is (by definition) less than 1. The square of a number less than 1 is SMALLER than the non-squared number. i.e. psi-squared should be smaller (not larger as you have shown) than psi. Can you please explain to me why you have shown the opposite of what should be happening?
The ratio of electric force and gravitational force between a proton and an electron is K e^2 / G memp ≅ 2.4 × 10^39. Q. Quantum mechanics doesn’t give the answer to the single most fundamental question: why electrons don’t collide with protons? Although, when it is applied to details it yields certain results… mathematically.
13:33 incredible explanation of the underlying commutator properties
from what i've read about him, the thumbnail is hilariously in character for wolfgang pauli lol
Hahaha :D
Example of Bosons are: uh yep yep mm yep that's the one yep yep
Good job
very clear explanation. Awesome Parth!
Heey Psrth! Good to see you! Long time no see, mate! 🤓
I can't hear the students, but it was hilarious when you said "that comes later. You are reading my thoughts, that's cool" 😆
So far so good, I'm in the indistinguishable part
Commute! Commute!
Good teacher indeed you are, Parth!
Wait but what if you swap 2 electrons in different orbitals and different spins. With the simplified math shown here both parts would have signs flip, and the wave functions would be identical before and after the switch which we just said wasn’t allowed for a system of 2 identical fermions. So there must be more. What’s missing?
I want to be like you when I grow up 😭! Such an amazing explanation!
What is the set of books with mathematical practice questions and that will make you expert-ish (gradually, if studied) in the field of quantum physics?
Linear Algebra and Differential Equations, especially those of the Sturm-Liouville type, are the two foundational mathematical branches applicable to Quantum Mechanics.
An advanced text on Classical Mechanics that covers Hamiltonian and Lagrangian formulations uses concepts like Phase Space and operators.
Love it. I now want to find out the missing bit - why do fermions have to have opposite spin? (I think it's something to do with angular momentum).
In the example he discusses, the spins have to be opposite (different spin state) because the orbital states are the same.
Ferromagnetic elements (Iron, Cobalt, Nickel, Gadolinium & Neodymium) and compounds are examples in which spins are aligned, but the orbital states are different. One can think of ferromagnetism as macroscopic quantum mechanics.
Your the best RUclipsr
His what?
@@gab25mars videos duh
@@odvothegod That's clearly not what he said.
@@odvothegod Your vs you're
100% agree. Such an amazing person and youtuber. The Best.
Very very good
Your videos helped me on my last semester, its really very impressive how you make these topic of qm. in such a simple way! Tqh parth
I literally enjoy your videos buddy.
Thank you very much!
please provide more videos with the simple explanation and long time duration like this ,as a layperson i really enjoyed with your content
Thanks so much for watching, and for the kind words!
I can't hear the students comments and contributions which seems they are part of the lecture.
If the universe exists because of identical particles, then why does the identical particle exist?.....and this question goes on ad infinitum...
It ends at the principle of Being itself really, which can be said to be the structure of reality fundamentally. In Being, all particles find their relations and connections, because Being itself is connection and relation.
I really enjoy your channel, in fact I’m becoming a Patreon donor. I actually learned most of your content 40 years ago, in college. Yes, I’m old. However, I never used this type of content in my chosen field, professional Pilot. As such, I would like to ask a question, to check my understanding. The “wave packet” is the probability of finding the particle in that location. The wave packet is “semi localized “ in that the highest probability of finding the particle is in a fairly small region, but the “tails” of the wave packet trail off towards zero fairly quickly, but never actually ever reach zero. As such, there is very small probability that the particle can be found out by the orbit of Jupiter, however that probability is so vanishingly small as to be practically zero. Is that a correct understanding?
Thank you so much! Yes as I understand it, your explanation is spot on :)
Do a video on dark matter and dark energy
The camera wasn't weird... It looks like it just got hit with sunlight as the day progressed.
Am always astounded by how much you get so much praise and literal presentations because ya get bedazzled by already established and well explored properties... As if it was new or yours...
All I could think was during that whole spiel was "antisymmetry" and outer products..
Also assuming you audience knows nothing, doesn't build a good presentation. Especially, when in fact the audience turns out, does know quite a bit. Unfortunately, the bystander effect (and vocabulary mismatches) takes hold of people answering well, much to the chagrin of presenters/teachers
I do not understand.
Why does the “end justify the means” in this explanation?
What is the mechanism keeping identical fermions from overlapping? If two identical fermions are on a collision course, how close do they get before that mechanism takes over, whatever it is?
Assuming our current model is completely accurate, what *practically* keeps electron orbitals from all collapsing in to 1s?
An Electron is not a photon, two 5c^3 particles will collide and bounce, they will do this regardless of polarity (i.e. "spin")
12:13
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