Fantastic he is back, some of the maths is too deep for me, but as he is doing it not me then it is still an enjoyable ride. At some point he will do the physics behind why money keeps disappearing from my wallet. My assumption is some sort of wave ( goodbye) function.
Okay, I wasn't ready to see how Pauli's exclusion principle can theoretically derive the bulk freaking modulus of solids! That is a level beyond insane!!!
Mahesh, Could you create a video explaining how the Higgs field changes the chirality of fermions between left-handed and right-handed states (using the chirality basis rather than the mass basis)? This mechanism explains how fermions acquire mass and proper time-it makes sense because the chirality changes enable fermions to have proper time, which corresponds to mass. Without this interaction, a left-handed fermion would remain left-handed indefinitely, similar to a photon, and thus, fermions would not have mass.
I'm retired and haven't thought about this stuff in years, yet find myself in the middle of the night watching it the whole way through. Younger up and coming scientists may not appreciate the gift of clear videos such as this, vs. trying to understand from a dry textbook, or dedicated time slot of a class. You can now learn when your mind is clearest and most receptive. The visual examples far exceed the chalkboard, and the ability to pause, rewind and replay cannot be understated. What a golden age of education, and how remarkable that Pauli could have formulated these concepts a century ago.
Couldn't agree more. I retired early partly to pursue studies I'd always wanted to do, and gained a masters degree in astrophysics. Even though it's somewhat more recent for me, these videos are not only a fantastic refresher but are giving me insights I never got while studying. I treat the _Physics Explained_ videos as a growing library of reference material and revisit them regularly. I'd highly recommend them as supplementary material to anyone studying physics or astrophysics.
despite of 1 year hiber, 3 videos in a row, from my very favorite physics channel? I must be dreaming. I don't use Patreon at all, because I myself is broken af but I think it's time to skip 3 meals per month just for this. I just can't have enough videos from him. best physics channel on youtube, because he touches very bottom of physics about "why this even?" rather than "how do we use this?".
You’re on a roll with these. I started self studying physics with the help of your videos years ago. And now I’m graduating this spring with my condensed matter physics degree. Videos like yours were instrumental in helping feed my motivation and curiosity about the universe, please keep making them!
You have returned in triumph! Absolutely love your stuff. Other channels give a heuristic, hand-wavy explanation of things, but you give us the real stuff. You are like the physics equivalent of 3blue1brown, and I wish more knew about this channel.
Hello! I'm currently on my first semester studying physics and I must say you've been a really big inspiration! I adore your videos and I thank you for everything you're doing. You're the best!
I first discovered this channel studying "Turning Points" module at A-Level. This video takes me back to Chemistry as well, where we were told that "electrons don't like sharing energy levels >:(, they must flip first", truthfully, I'm grateful for because the math is far beyond me. Watching this video long after the fact has sparked a new way for me to think about chemical bonding. Thanks :)
2 วันที่ผ่านมา +1
You might be interested in how ionic or covalent bonds are enabled by quantum mechanics. In particular, addition of angular momentum in QM, though it might be math heavy for some.
Your 3d quantum number lattice explains the structure of the periodic table, and made me think of a new? way of representing the table. The fact that energy follows a spherical growth also I think explains why there is some skipping of quantum numbers in larger atoms, because they are actually a lower energy.
thermodynamics is a weird one, probably because the definitions aren't very clear, it was developed by engineers mostly and the language can be pretty vague, probably because a better formulation (statistical mechanics) already exists. It took me quite a bit of reading to understand the bulk of it, but I still don't have a clear view of the whole thing (especially around the gibbs free energy and potential functions part) my recommendation would be Thermal physics by Shroeder
thats true , i myself am an engineering student , and thermodynamics is the least intuitive subject for me , the definitions are pretty vague , but to be honest its not that hard to work around with , the exams are usually straight forward applications , but i cant digest it quite yet
@@ghrababderrahmen2457 yeah, reading Shroeder should give you a really good idea of Entropy and heat engines at least, that is a good place to start. All the vagueness about other things should go away after statistical mechanics, or so I have heard
I am a student at UIUC studying nuclear engineering and chemistry, and I struggle to find good resources which fill in the small gaps between my classes. Nuclear and quantum are scarcely talked about in detail outside of academia. So to see such a well presented and thought out video covering the thin connection between chemistry (valance electron clouds) and quantum is like Prometheus taking a detour to bestow scarcely spoken knowledge. Thank you!
When the year is starting off with uncertainty to our rights and expression as humans, you bring mathematical clarity to some of the most foundational aspects of our lives. Thank you for this video
Thank you so much for these superb videos. You are pioneering a new science communication genre, aimed at an enormous audience: those of us with a bit of mathematical training and those untroubled by unfamiliar symbols, to see for the first time a much more real and actual model of nature. I am grateful. I hope you find making these videos rewarding and sustainable.
1000th like! Jokes aside, I like your content. Straight and to the point and based on the actual Maths involved. Great for students and scientists alike
I have watched some of these at least 20 times, to the point where I can do the mathematics myself, and explain it well to others.
23 ชั่วโมงที่ผ่านมา +1
You always considered non interacting particles in the derivations. But electrons repel each other. How big is the contribution of coulomb repulsion in the "hand thru the wall" idea?
Hey, I have a few questions that could make for an interesting future video if you're interested. It's about nuclear weapons and their blast mechanics. 1. When we see a nuclear blast in videos, there's an initial bright flash, followed by a sudden dimming, and then glowing, point-like shredded pieces scattering around before the brightness intensifies again. What's happening in this process? 2. In fission weapons, the blast intensity increases exponentially due to a chain reaction, where each fission event releases multiple neutrons that cause further reactions, rapidly escalating the energy release. But in fusion weapons, which are said to be more destructive than fission, how does the rate of energy release compare? Is it even more rapid? Would it follow a steeper exponential curve, or perhaps something like a factorial growth? 3. Antimatter weapons are purely theoretical at this point, but their potential blast mechanics are intriguing. How would an antimatter explosion compare to fusion or fission in terms of energy release patterns? If this isn't your area of expertise, that's totally fine, but I'd love to hear your thoughts or see a video on this in the future.
This is as entertaining as all the other "edutainment" channels out there. Unlike those channels, these videos actually go in-depth on the topic and you don't forget what you saw by tomorrow.
Yes mm well, getting the number of powers of 10 correct is of course well done. Thank you for the video, I'll probably revisit this one shortly. Pauli was quite a wizard with spectra and maths.
13:02 The infinite square well basically requires that all probabilities at x coordinates 0 and 1 for either particle be zero. If we instead specify that the probabilities at x coordinates of 0 and 1 for a given particle be equal, we effectively end up with a circular space with no potential barrier anywhere. You can't have states of definite momentum in an infinite square well because the particles keep bouncing off the walls, but in our circular space, I believe our energy states for the particles end up each (except in the N=1 case) splitting into 2 momentum states, so the strict requirement of a spatially (anti)symmetric wavefunction goes away as long as no contour lines cut exactly perpendicular to the x1=x2 line, and as long as the x1=x2 line is a contour of the wavefunction of the energies of the particles are equal. Or something like that.
AT 10:03, there was a question of "What is the solution?" But the previous question is "What is the problem?" You switched an exited number for a base state number and got a different probability density. It should be different and it appears different. What is the problem?
The problem is exactly that we got a different density. Not because we changed to base state but because we exchanged the particles. If the particles are indistinguishable then exchanging them must not change the physics. But a different probability density represents a different physical scenario.
@@narfwhals7843 Thank you for the response. But I assume that one particle which was in an excited state is now in the base state, and the one that was in the base state is now in the excited state and so they are no identical anymore. I suppose I am assuming that they "carry" the adjective "excited' (and whatever that implies in reality) down to the base state, while the other particle does the opposite. Thus, because they are in two different states, they are no longer indistinguishable. Perhaps the video is just not clear on what "swap the position labels" (at 8:56) means. And, is the density plotting done in reality or in modeling the formula alone?
Great video! To be nitpicky, in the case of the inability to push a hand through a wall, it’s more due to electrons resisting each other electrically, rather than the exclusion principle, right?
Okay I have a question: When we say distinguishable particles, what do we mean by that? Does that mean we need these particles are described by two seperate wavefunction rather than one?
The problem with these kind of videos is this that there are so many non realistic assumptions in this and then they go on to derive such fragmented results of physics which is precisely the reason why physics has become too much fragmented today as we see it because of such fragmented approach.
I have some questions annoying me - why cross product of vectors, determinants are defined the way they are.from where did they come from? Also how angular velocity and angular displacement, torque etc. are vectors and why are their direction given by screw rule? Please answer
One thing that confuses me is what "antisymmetric" means when we start dealing with QFT where there's not a definite number of particles. A symmetric classical field is easy to envision (all of the waves we're familiar with in everyday life involve symmetric fields), but it would be nice to see a toy model of a simple-as-possible antisymmetric field and how waves propagate in such a field.
A wavefunction describing two particles should describe, for one thing, the probability of observing one in one location and the other in another location. As such, it should have two inputs for the two different locations. If you were just adding the two wavefunction, the resulting function would only have one input. Adding the two wavefunctions would, rather than corresponding to having two particles, would instead be a non-normalized wavefunction for a single particle, which would be a superposition of the two wavefunctions you started with (“superposition” just means “linear combination” after all).
In the 1D example of an infinite potential well, assuming there's a spin 'up' electron occupying the lowest energy state (E1), if we were to introduce another spin up electron into this system, would it change its spin to occupy E1 or would it occupy E2?
if the pauli exclusion principle causes matter to have structure then not falling through the floor is acceleration, where does this energy come from? It can resist gravity so there has to be energy use to balance that.
Moving charges create fields hence electrons separated by space must conserve the angular momentum therefore being relatively separate entities without which they wouldn't be able to produce fields relative to each other and become unstable.
My professor’s intuitive explanation of electron spin: “Imagine a ball spinning around its axis but the ball is not a ball but a dimensionless point and nothing is actually spinning.”
The Pauli Exclusion Principle is a fundamental concept in quantum mechanics, formulated by Austrian physicist Wolfgang Pauli in 1925. It states that no two fermions (particles with half-integer spin, such as electrons, protons, and neutrons) can occupy the same quantum state within a quantum system simultaneously. In simpler terms, two fermions cannot have the exact same set of quantum numbers. Quantum numbers describe properties of particles in atoms, including: principal quantum number (n), which indicates the energy level of the electron; angular momentum quantum number (l), which determines the shape of the orbital; magnetic quantum number (m), which relates to the orientation of the orbital in space; and spin quantum number (s), which describes the intrinsic spin of the particle, and can be either +1/2 or -1/2 for electrons. According to the Pauli Exclusion Principle, no two electrons in the same atom can share all four quantum numbers. This explains why electrons in an atom occupy different orbitals and energy levels, leading to the structure of the periodic table and the formation of chemical bonds. The significance of the principle is profound. It plays a key role in atomic structure by helping explain the arrangement of electrons in atoms, their energy levels, and the periodic table’s structure. It explains why electrons fill lower energy orbitals first, and why each element has a unique electron configuration. The principle also contributes to the stability of matter at a macroscopic scale. Without it, electrons would collapse into the lowest energy state, and matter as we know it would not exist. It is crucial in phenomena such as the degeneracy pressure in white dwarf stars, which prevents them from collapsing further under gravity. In terms of chemical properties, the exclusion principle explains why atoms of different elements have distinct chemical properties. The unique electron configuration of each element defines how it interacts chemically, contributing to the vast diversity of elements and compounds. In solid-state physics, the Pauli Exclusion Principle helps explain phenomena such as electrical conductivity, magnetism, and the behavior of electrons in metals and semiconductors. The Pauli Exclusion Principle highlights the fundamental differences between fermions and bosons (particles with integer spin), as bosons do not obey this principle and can occupy the same quantum state. This is why, for example, photons (bosons) can exist in the same quantum state, leading to phenomena like lasers and Bose-Einstein condensates. In essence, the Pauli Exclusion Principle is central to our understanding of quantum systems and the behavior of matter at microscopic scales. It not only governs the arrangement of particles in atoms but also influences the properties of larger systems such as solids, stars, and the universe itself.
The classical answer is electromagnetic interactions, which works for most situations. Stellar cores, white dwarfs, neutron stars and such aren’t in the realm of classical physics. For those you need a deeper answer.
Is it not amazing that Pauli formulated all of this maths without all this maths used herein by Physics Explained. Apparently, using spectra alone he deduced his principle; I recall that the Sterns-Gerlach work had not yet happened.
Best news of 2025 has been physicsexplained's sudden, unannounced, and unexpected return to making videos.
And Viascience too!
Let's then sit back and enjoy the ride...
Fantastic he is back, some of the maths is too deep for me, but as he is doing it not me then it is still an enjoyable ride.
At some point he will do the physics behind why money keeps disappearing from my wallet. My assumption is some sort of wave ( goodbye) function.
real!!
Real
Okay, I wasn't ready to see how Pauli's exclusion principle can theoretically derive the bulk freaking modulus of solids! That is a level beyond insane!!!
I came here by your post.. ❤️🔥
Just saw your community post and jumped here… thanks for the recommendation ❤
Came here from your recommendation ❤
Mahesh, Could you create a video explaining how the Higgs field changes the chirality of fermions between left-handed and right-handed states (using the chirality basis rather than the mass basis)? This mechanism explains how fermions acquire mass and proper time-it makes sense because the chirality changes enable fermions to have proper time, which corresponds to mass. Without this interaction, a left-handed fermion would remain left-handed indefinitely, similar to a photon, and thus, fermions would not have mass.
I'm retired and haven't thought about this stuff in years, yet find myself in the middle of the night watching it the whole way through. Younger up and coming scientists may not appreciate the gift of clear videos such as this, vs. trying to understand from a dry textbook, or dedicated time slot of a class. You can now learn when your mind is clearest and most receptive. The visual examples far exceed the chalkboard, and the ability to pause, rewind and replay cannot be understated.
What a golden age of education, and how remarkable that Pauli could have formulated these concepts a century ago.
Couldn't agree more. I retired early partly to pursue studies I'd always wanted to do, and gained a masters degree in astrophysics. Even though it's somewhat more recent for me, these videos are not only a fantastic refresher but are giving me insights I never got while studying. I treat the _Physics Explained_ videos as a growing library of reference material and revisit them regularly. I'd highly recommend them as supplementary material to anyone studying physics or astrophysics.
He’s not afraid to dig down deep into the math and explain it a bit
You're an amazingly talented educator.
despite of 1 year hiber, 3 videos in a row, from my very favorite physics channel? I must be dreaming.
I don't use Patreon at all, because I myself is broken af but I think it's time to skip 3 meals per month just for this. I just can't have enough videos from him.
best physics channel on youtube, because he touches very bottom of physics about "why this even?" rather than "how do we use this?".
You’re on a roll with these. I started self studying physics with the help of your videos years ago. And now I’m graduating this spring with my condensed matter physics degree. Videos like yours were instrumental in helping feed my motivation and curiosity about the universe, please keep making them!
Float head physics
Bro is making banger after banger recently
You have returned in triumph! Absolutely love your stuff. Other channels give a heuristic, hand-wavy explanation of things, but you give us the real stuff. You are like the physics equivalent of 3blue1brown, and I wish more knew about this channel.
My man is dropping banger after banger, 2025 is off to a good start
Fantastic!
I like how you don't skip intermediate steps in the calculations and don't jump to the final results.
My first semester teaching (undergrad) QM by myself--so thankful you're back!!
The elegance with which that video explains one of the fundamental principles of our cosmos, is astonishing.
Hello! I'm currently on my first semester studying physics and I must say you've been a really big inspiration! I adore your videos and I thank you for everything you're doing. You're the best!
Good choice my friend, have fun
BRO LETS GOOOOOOOO.THIS GUY IS ONE OF THE BEST TEACHERS OUT THERE AND I AM
SO GRATEFUL HE IS BACK.LETS SUPPPORT HIM GUYS
I didn't have the resolve to finish a physics degree, but I still like understanding what's going on. Your videos are just right for that
The wrap-up and conclution on this one was stellar, glad to have you back!
I first discovered this channel studying "Turning Points" module at A-Level. This video takes me back to Chemistry as well, where we were told that "electrons don't like sharing energy levels >:(, they must flip first", truthfully, I'm grateful for because the math is far beyond me. Watching this video long after the fact has sparked a new way for me to think about chemical bonding. Thanks :)
You might be interested in how ionic or covalent bonds are enabled by quantum mechanics. In particular, addition of angular momentum in QM, though it might be math heavy for some.
Your 3d quantum number lattice explains the structure of the periodic table, and made me think of a new? way of representing the table. The fact that energy follows a spherical growth also I think explains why there is some skipping of quantum numbers in larger atoms, because they are actually a lower energy.
A clear and very gentle presentation of QM principles. Thank you very much.
Thank you very much for those amazing new videos. This is the best physics channel.
Spectacular! I always wondered about the fundamental basis of the Pauli exclusion principle. And you explained it so well.
bro please do a thermodynamics video , i am so screwed
I wish I had YT when I was taking thermodynamics 1 and 2 in the 1980s.
I am not screwed but I'd love to learn thermodynamics
thermodynamics is a weird one, probably because the definitions aren't very clear, it was developed by engineers mostly and the language can be pretty vague, probably because a better formulation (statistical mechanics) already exists. It took me quite a bit of reading to understand the bulk of it, but I still don't have a clear view of the whole thing (especially around the gibbs free energy and potential functions part)
my recommendation would be Thermal physics by Shroeder
thats true , i myself am an engineering student , and thermodynamics is the least intuitive subject for me , the definitions are pretty vague , but to be honest its not that hard to work around with , the exams are usually straight forward applications , but i cant digest it quite yet
@@ghrababderrahmen2457 yeah, reading Shroeder should give you a really good idea of Entropy and heat engines at least, that is a good place to start. All the vagueness about other things should go away after statistical mechanics, or so I have heard
Your presentations are consistently excellent… and have a reassuring solidity.
I am a student at UIUC studying nuclear engineering and chemistry, and I struggle to find good resources which fill in the small gaps between my classes. Nuclear and quantum are scarcely talked about in detail outside of academia. So to see such a well presented and thought out video covering the thin connection between chemistry (valance electron clouds) and quantum is like Prometheus taking a detour to bestow scarcely spoken knowledge. Thank you!
Yes yes yes, 3 gifts in January! Thank you so much. On this cold January night, I have something to keep me warm.
When the year is starting off with uncertainty to our rights and expression as humans, you bring mathematical clarity to some of the most foundational aspects of our lives. Thank you for this video
So glad you are back! 🎉
A tough subject covered in a remarkably concise manner. Kudos.
Many thanks for coming back! Great content and approach!
Monsieur, you're spoiling us!! Chapeau. I remember doing this in the late 80s and marvelling. Also, the fun in 2 dimensions.
Fantastic content, thanks for coming back
Keep making physics content bro, your videos are so good, they are like my university lecture of physics
im gonna sleep so fucking good tonight and dream of quantum uncertainty, a beautiful combination
Such a wonderful surprise this release!
It is like an escape into fantasy land. No politics, no woke ideology, just Bliss.
Thank you so much for these superb videos. You are pioneering a new science communication genre, aimed at an enormous audience: those of us with a bit of mathematical training and those untroubled by unfamiliar symbols, to see for the first time a much more real and actual model of nature. I am grateful. I hope you find making these videos rewarding and sustainable.
1000th like! Jokes aside, I like your content. Straight and to the point and based on the actual Maths involved. Great for students and scientists alike
Return of the King
Glad you are uploading again. Thank you for all your help
And once more he does it again, 40 min, it's like christmas again
I’ve been awaiting your return and it has been well worth it!
Cảm ơn bạn!
best physics channel hands down
I have watched some of these at least 20 times, to the point where I can do the mathematics myself, and explain it well to others.
You always considered non interacting particles in the derivations. But electrons repel each other. How big is the contribution of coulomb repulsion in the "hand thru the wall" idea?
Is a spin statistic theorem video a possibility in future? Always happy to see this channel post new videos
Excellent video! Remarkable!
These explanations and examples are on par with Griffiths and McIntyre readings. Please keep making videos !
Fantastic video. I just love your clarity
We are truly spoilt here!
Thanks so much for your beautiful videos.
Hey, I have a few questions that could make for an interesting future video if you're interested. It's about nuclear weapons and their blast mechanics.
1. When we see a nuclear blast in videos, there's an initial bright flash, followed by a sudden dimming, and then glowing, point-like shredded pieces scattering around before the brightness intensifies again. What's happening in this process?
2. In fission weapons, the blast intensity increases exponentially due to a chain reaction, where each fission event releases multiple neutrons that cause further reactions, rapidly escalating the energy release. But in fusion weapons, which are said to be more destructive than fission, how does the rate of energy release compare? Is it even more rapid? Would it follow a steeper exponential curve, or perhaps something like a factorial growth?
3. Antimatter weapons are purely theoretical at this point, but their potential blast mechanics are intriguing. How would an antimatter explosion compare to fusion or fission in terms of energy release patterns?
If this isn't your area of expertise, that's totally fine, but I'd love to hear your thoughts or see a video on this in the future.
Another excellent lecture.
amazing videos just as always, i am hoping to see next new videos soon
This is as entertaining as all the other "edutainment" channels out there. Unlike those channels, these videos actually go in-depth on the topic and you don't forget what you saw by tomorrow.
he’s back!
*scrolls a lil further*
with 3 videos oh my goddd
Yes mm well, getting the number of powers of 10 correct is of course well done.
Thank you for the video, I'll probably revisit this one shortly. Pauli was quite a wizard with spectra and maths.
Spin is mind bending.
Legitimately learned more in the first 3 minutes than in my quantum mechanics undergraduate course. 😐
OUTSTANDING video.
he has retunred welcome back brother
Fantastic video!
13:02 The infinite square well basically requires that all probabilities at x coordinates 0 and 1 for either particle be zero. If we instead specify that the probabilities at x coordinates of 0 and 1 for a given particle be equal, we effectively end up with a circular space with no potential barrier anywhere.
You can't have states of definite momentum in an infinite square well because the particles keep bouncing off the walls, but in our circular space, I believe our energy states for the particles end up each (except in the N=1 case) splitting into 2 momentum states, so the strict requirement of a spatially (anti)symmetric wavefunction goes away as long as no contour lines cut exactly perpendicular to the x1=x2 line, and as long as the x1=x2 line is a contour of the wavefunction of the energies of the particles are equal.
Or something like that.
Another great physicist entering the community.
Masterpiece!
3 videos in the space of 2 weeks. Do not stop cooking because I might kms getting through theoretical phys 2nd year without your videos 😂
Are we allowed to use calculus on discrete value n?
appreciate your content! Let's gooooo!!!
That's epic! Can you do thermodynamics too? I would love to learn it
Another bager. Brilliant
AT 10:03, there was a question of "What is the solution?" But the previous question is "What is the problem?" You switched an exited number for a base state number and got a different probability density. It should be different and it appears different. What is the problem?
The problem is exactly that we got a different density. Not because we changed to base state but because we exchanged the particles. If the particles are indistinguishable then exchanging them must not change the physics. But a different probability density represents a different physical scenario.
@@narfwhals7843 Thank you for the response. But I assume that one particle which was in an excited state is now in the base state, and the one that was in the base state is now in the excited state and so they are no identical anymore. I suppose I am assuming that they "carry" the adjective "excited' (and whatever that implies in reality) down to the base state, while the other particle does the opposite. Thus, because they are in two different states, they are no longer indistinguishable. Perhaps the video is just not clear on what "swap the position labels" (at 8:56) means. And, is the density plotting done in reality or in modeling the formula alone?
We love you man!
Great video! To be nitpicky, in the case of the inability to push a hand through a wall, it’s more due to electrons resisting each other electrically, rather than the exclusion principle, right?
Request you to make a detailed video on Einstein's general relativity
i waited so long
Okay I have a question: When we say distinguishable particles, what do we mean by that?
Does that mean we need these particles are described by two seperate wavefunction rather than one?
Great ❤❤❤
Amazing video! :D at 31:40 there's a little typo, where "State" is spelled "Spate"
The problem with these kind of videos is this that there are so many non realistic assumptions in this and then they go on to derive such fragmented results of physics which is precisely the reason why physics has become too much fragmented today as we see it because of such fragmented approach.
I have some questions annoying me - why cross product of vectors, determinants are defined the way they are.from where did they come from? Also how angular velocity and angular displacement, torque etc. are vectors and why are their direction given by screw rule?
Please answer
One thing that confuses me is what "antisymmetric" means when we start dealing with QFT where there's not a definite number of particles. A symmetric classical field is easy to envision (all of the waves we're familiar with in everyday life involve symmetric fields), but it would be nice to see a toy model of a simple-as-possible antisymmetric field and how waves propagate in such a field.
Why is the wave function of 2 particles the product and not the sum of the wavefunctions?
Great question.
A wavefunction describing two particles should describe, for one thing, the probability of observing one in one location and the other in another location. As such, it should have two inputs for the two different locations. If you were just adding the two wavefunction, the resulting function would only have one input. Adding the two wavefunctions would, rather than corresponding to having two particles, would instead be a non-normalized wavefunction for a single particle, which would be a superposition of the two wavefunctions you started with (“superposition” just means “linear combination” after all).
In the 1D example of an infinite potential well, assuming there's a spin 'up' electron occupying the lowest energy state (E1), if we were to introduce another spin up electron into this system, would it change its spin to occupy E1 or would it occupy E2?
Please make videos about statestical mechanics
Isnt the column force do the resistance before Paulis exclusion principle?
Don't be lazy to learn because knowledge is a treasure that we can take anywhere without burdening us.
if the pauli exclusion principle causes matter to have structure then not falling through the floor is acceleration, where does this energy come from? It can resist gravity so there has to be energy use to balance that.
underrated
4:24 missing t in the exponent - lovely video anyway
Just love you man
Another exciting video!
Any fundamental reason why you didnt model electrons as having higher spin values? Why only 1/2?
Why calculated value of k is higher than experimental? I would expect it'd be lower, because we didn't include electromagnetic forces
I thought the world was ending. But Physics Explained apparently spent the past 2 years devising a plan to save it.
Fingers crossed!
The first 2 years of the incarcerated lockdown, this is all I watched. It helped me through.
Moving charges create fields hence electrons separated by space must conserve the angular momentum therefore being relatively separate entities without which they wouldn't be able to produce fields relative to each other and become unstable.
I'm confused: if all electrons are indistinguishable from each other, how can it be that some of them are spin-up while others spin-down?
You don’t know which one is spin up and which one is spin down.
My professor’s intuitive explanation of electron spin:
“Imagine a ball spinning around its axis but the ball is not a ball but a dimensionless point and nothing is actually spinning.”
44:44 Ah, finally a Ghastly Expression. I've been deprived for so long!
Hi Dr. Physics!
I love ghastly expressions!
The Pauli Exclusion Principle is a fundamental concept in quantum mechanics, formulated by Austrian physicist Wolfgang Pauli in 1925. It states that no two fermions (particles with half-integer spin, such as electrons, protons, and neutrons) can occupy the same quantum state within a quantum system simultaneously. In simpler terms, two fermions cannot have the exact same set of quantum numbers.
Quantum numbers describe properties of particles in atoms, including: principal quantum number (n), which indicates the energy level of the electron; angular momentum quantum number (l), which determines the shape of the orbital; magnetic quantum number (m), which relates to the orientation of the orbital in space; and spin quantum number (s), which describes the intrinsic spin of the particle, and can be either +1/2 or -1/2 for electrons.
According to the Pauli Exclusion Principle, no two electrons in the same atom can share all four quantum numbers. This explains why electrons in an atom occupy different orbitals and energy levels, leading to the structure of the periodic table and the formation of chemical bonds.
The significance of the principle is profound. It plays a key role in atomic structure by helping explain the arrangement of electrons in atoms, their energy levels, and the periodic table’s structure. It explains why electrons fill lower energy orbitals first, and why each element has a unique electron configuration.
The principle also contributes to the stability of matter at a macroscopic scale. Without it, electrons would collapse into the lowest energy state, and matter as we know it would not exist. It is crucial in phenomena such as the degeneracy pressure in white dwarf stars, which prevents them from collapsing further under gravity.
In terms of chemical properties, the exclusion principle explains why atoms of different elements have distinct chemical properties. The unique electron configuration of each element defines how it interacts chemically, contributing to the vast diversity of elements and compounds.
In solid-state physics, the Pauli Exclusion Principle helps explain phenomena such as electrical conductivity, magnetism, and the behavior of electrons in metals and semiconductors.
The Pauli Exclusion Principle highlights the fundamental differences between fermions and bosons (particles with integer spin), as bosons do not obey this principle and can occupy the same quantum state. This is why, for example, photons (bosons) can exist in the same quantum state, leading to phenomena like lasers and Bose-Einstein condensates.
In essence, the Pauli Exclusion Principle is central to our understanding of quantum systems and the behavior of matter at microscopic scales. It not only governs the arrangement of particles in atoms but also influences the properties of larger systems such as solids, stars, and the universe itself.
why did you paste a gpt answer here
The classical answer is electromagnetic interactions, which works for most situations. Stellar cores, white dwarfs, neutron stars and such aren’t in the realm of classical physics. For those you need a deeper answer.
why cant we just replace the word spin with curl?
Is it not amazing that Pauli formulated all of this maths without all this maths used herein by Physics Explained. Apparently, using spectra alone he deduced his principle; I recall that the Sterns-Gerlach work had not yet happened.