As always, thanks for watching everyone! If you'd like to check out some more quantum physics videos, feel free to head over to my playlist here: ua-cam.com/play/PLOlz9q28K2e4Yn2ZqbYI__dYqw5nQ9DST.html And of course, let me know what other topics I should cover in the future!
I have had a QM question for several years and have not yet gotten a physicist to give me a satisfactory answer. The usual first example of Feynman diagrams is two electrons scattering as the result of exchanging one photon. We know from electrostatics that two electrons, having like charge, must repel and the Feynman diagram is drawn to show this. The example is easily extended to two positively charged particles, such as protons. But what about the case of a positively charged and a negatively charged particle exchanging one photon. We know this must result in attraction, the direction of the momentum change vector must be reversed. The photon is the only means of transferring anything between the particles. How does QM explain that a photon emitted by a particle in one instance causes repulsion and presumably an identical photon in the other instance causes attraction?
The Feynman path integral shows it. If you sum all possible scenario how two charge particles interact you'll get that two electrons repel each other but electron and proton attract.
@@MrSolessi Anybody can stick a negative sign in an equation. (Though I imagine Feynman’s way of doing it is cleverer than most.) My question is what physical property is at work. When a photon is emitted, it can have no idea whether it’s going to encounter a positive or a negative particle. Somehow, it has to carry a memory of the charge of the particle that emitted it. Or, perhaps all possible photons emitted by a particle have to jointly carry a memory of the charge of the emitting photon. Or maybe there is a more subtle explanation, but something in the process has to transmit the “knowledge” of the charge of the emitting particle. What is it?
Hi Parth! Could you please clarify the following. Before measurement, the spin is in some superposition state in 3D space along all 3 axes, right? We can only measure it along one axis at a time? Why is the spin along y-axis is a superposition of two states along the z-axis (not y-axis itself)? Can the spin along y-axis be a superposition of two states along x-axis? Thank you!
It can. Actually after measuring Sy the particle is collapsed in an eigenstate of Sy. Parth showed this eigenstate as a superposition of Sz states because he is measuring Sz after this Sy measurement. But if you measured Sx instead you would have to write this same eigenstate as a superposition of Sx states so that it becomes easier to see the measurement eigenvalues and corresponding probabilities.
Hey nice video. Can you do a video on superdeterminism? see last video of sabine hossenfelder. and why statistical independence is postulated in current quantum mechanical theories.
have a doubt sir. In wave propagation water or sound , how individual particle vibrations are transmitted from particle to particle in the direction of wave propagation? There are gaps between particles in solids, liquids and gases. Is this not against principle of locality?
Mass is a photon of 2pi planck wavelength trapped over own schwartzchild radius. Gosh...in quark math there is a charge pair "canceling out". What if instead they became a photon, since that's what a photon is. And since they are being create inside a nucleus it must be fairly short wavelength. m=E/c^2. Mass is energy in orbit. Gaining angular momentum orbiting a Planck
Hi, great video! I have a question: What exactly is the argument against a particle like an electron is actually spinning? My answer would be that elementary particles don't really have a volume (?) nor a surface which means that you can't determine if it's spinning or not. Is that the ordinary explanation?
When something spins, parts of an object are revolving around a center. So rotation inherently needs something to be made up from other things. Electrons are not made up of other things.
@@dertechl6628 I agree that the electron is an elementary particle and is not made up of other things, but that does not mean it is infinitesimal. No one knows if the electron has structure, so no one can say that it is not actual rotating.
These videos are always great, and really easy to comprehend :) If you're ever looking for video ideas, have you considered creating a series of videos to run through something like the basics of quantum mechanics or general relativity, like the physics version of 3Blue1Brown's "Essence of Calculus/Linear Algebra" series? I know most of that information is already in videos you've made, but it'd be super interesting to see it all laid out in order as a definite series!
One problem for me is, if one says spin is a type of angular momentum shouldn’t there be an associated energy coming with this? But the energy of a particle at rest in vacuum with spin, is just it‘s rest mass(neglecting vacuum fluctuations). I know that the dimension of Spin is the same dimension as angular momentum and it builds the same algebra as angular momentum, but are these the only reasons why one can say it‘s a type of angular momentum?
Let k = h/2pi; Kinetic energy of rotation = p^2/2m, so actually that means this part of any particle's mass-energy is actually just latent angular momentum. You can actually work out exactly what special length you would have to approximate the particle's radius as for this rotational energy to exactly equal the mass energy of the particle: k/l = p; p^2/2m=mc^2; p/sqrt(2) = mc = k/sqrt(2)l; l=k/(mc sqrt(2)), which for particles with masses on the order of 1e-20 kg, this length will be on the order of 1e-12 meters. More precise numbers and considering the inertia of a sphere or a ball will provide various differing answers
@@MrRyanroberson1 Consider that the h bar/square root of [2] is the kinetic constant of any subatomic partcle, I think part of the confusion is that the kinetic value is inherent to the total energy value if the potential energy value is 0 provided the particle is moving through a vacuum. Just to add, that creates the angular momentum value which is why it is noted as h bar/ square root of 2 as it can be graphed to show its angle given the wave function.
@@Stephanpar23 so you can pick any arbitrary direction and axis you want, so does tbat mean fkr whatever axis you pick the spin will collapse alobg tbat direction, and the wavefunction will collpase to a particle aligned along that axis, I surmise? Is that right?
@@leif1075 Exactly. As the particle is measured, the wave function will collapse into one of two states regardless of where it is measured. This allows us to understand the angular momentum of the particle by deriving the wave function from the Schrodinger Equation. This derivative will tell us how the particle propagates through space time with respect to the overall kinetic value of the particle and the potential value of the environment set as our operator. I'm a little uncertain of the operator but I believe it sets the eigenvalue of our function as we obtain the derivative.
Hey, y'all. Physics enthusiast here. I actually read about spin in a text book I bought. So, I'm going to take a crack at the question. Energy from spin would not contribute to the rest mass, but to the total energy. We have experiments that can identify specific tests masses with great precision with no contribution of any type of momentum (separate discussion). As for spin, we experimentally observe the effects of its magnetic dipole moment when there should be none. For example, sending a beam of electrons through a charged field. If you have the field set so the electrons travel straight through, you will find that they never go straight. They will always go slightly up or slightly down, as if they were spinning charges some with an axis pointing up and some pointing down. No one knows why this happens, but the Dirac and others introduced the math to incorporate this behavior in Quantum Mechanics.
Is there any work done on this which will not describe this in probabilistic way or finding the exact position of a particle before measurement? I mean it does sound a little impossible but still have you come acrossed something like this?
I am fascinated currently with Geometric Algebra and was thinking that some ideas in that have been used to encode quantum spin states. Have you explored those ideas?
Parth🌟🌟🌟,....If an spin detector DETECTS spin of a neutron.....untill we measure what the spin the DETECTOR HAS DETECTED WAVE FUNCTION DOES NOT COLLAPSE..... RIGHT WHY DETECTION DOES NOT COLLAPSE THE WAVE FUNCTION....BUT THE MEASUREMENT OF THE DETECTION COLLAPSES THE WAVE FUNCTION....WHY DETECTION IS NOT AN MEASUREMENT? THANK YOU parth
You could argue that a unique one sylllable sound corresponding to the symbol 0 is a necessary condition for evaluating the proposition, 0 is the number "0", as either true, or false, like A is the letter "A", otherwise you're left with an undecideable, Kantian synthetic apriori proposition, where the subject '0' contains the predicate 'is the number zero'.
External magnetic field is a pseudovector. A single test electron inside this field can have two distinct possible relative orientations with respect to the direction of magnetic pseudovector. So an aparatus for determining electron spin is using magnetic field. Is there in theory a way to measure spin using gravitational field?
what if e- spin cuz of its composition ie the quarks since they r born with quarks they spin from there birth 2 up and a down which forces the e- to rotate
Electrons have mass, could that mean that they also have some (even if tiny) volume after all and that physical spin operates in that volume? Just wondering...
Hey Parth, Thank you so much for your content. It isn't easy to get along channels on youtube that give mathematical intuition about the physics discussed but still in a fun and interesting way. You really make that work. Keep it going and have a great end of the year and a great start into the new year Cheers
I conceive it as spikes in all directions from a point, being outward force or inward force, and therefore, positive➕ or negative. Spin states are Levo or Dextro due to deflection.
As always, thanks for watching everyone! If you'd like to check out some more quantum physics videos, feel free to head over to my playlist here: ua-cam.com/play/PLOlz9q28K2e4Yn2ZqbYI__dYqw5nQ9DST.html
And of course, let me know what other topics I should cover in the future!
Id like to see you derive them!
Yes, I want to see you derive the Pauli Matrices, and even higher order Matrices. That sounds fun, I love the math!
Yes, please show the derivation of the Pauli matrices - I see this everywhere but have never seen the derivation. Thanks, great vids.
eigenchris spinors series
Amazing video, thanks a lot. Yes, please do more about this mathematics.
I like the way the Pauli spin matrices just fall out of geometric algebra. Have to find an explanation that uses that geometry.
I have had a QM question for several years and have not yet gotten a physicist to give me a satisfactory answer. The usual first example of Feynman diagrams is two electrons scattering as the result of exchanging one photon. We know from electrostatics that two electrons, having like charge, must repel and the Feynman diagram is drawn to show this. The example is easily extended to two positively charged particles, such as protons. But what about the case of a positively charged and a negatively charged particle exchanging one photon. We know this must result in attraction, the direction of the momentum change vector must be reversed. The photon is the only means of transferring anything between the particles. How does QM explain that a photon emitted by a particle in one instance causes repulsion and presumably an identical photon in the other instance causes attraction?
The Feynman path integral shows it. If you sum all possible scenario how two charge particles interact you'll get that two electrons repel each other but electron and proton attract.
@@MrSolessi Anybody can stick a negative sign in an equation. (Though I imagine Feynman’s way of doing it is cleverer than most.) My question is what physical property is at work. When a photon is emitted, it can have no idea whether it’s going to encounter a positive or a negative particle. Somehow, it has to carry a memory of the charge of the particle that emitted it. Or, perhaps all possible photons emitted by a particle have to jointly carry a memory of the charge of the emitting photon. Or maybe there is a more subtle explanation, but something in the process has to transmit the “knowledge” of the charge of the emitting particle. What is it?
Hi Parth! Could you please clarify the following. Before measurement, the spin is in some superposition state in 3D space along all 3 axes, right? We can only measure it along one axis at a time? Why is the spin along y-axis is a superposition of two states along the z-axis (not y-axis itself)? Can the spin along y-axis be a superposition of two states along x-axis? Thank you!
It can. Actually after measuring Sy the particle is collapsed in an eigenstate of Sy. Parth showed this eigenstate as a superposition of Sz states because he is measuring Sz after this Sy measurement. But if you measured Sx instead you would have to write this same eigenstate as a superposition of Sx states so that it becomes easier to see the measurement eigenvalues and corresponding probabilities.
Hey nice video.
Can you do a video on superdeterminism? see last video of sabine hossenfelder.
and why statistical independence is postulated in current quantum mechanical theories.
as always Parth fantastic video! I was wondering if you did a thesis and was it on QM? Cheers
So I’m getting into physics calculus and proofs this next semester. I was wondering if you could do a video on LaTeX and where to get it?
have a doubt sir. In wave propagation water or sound , how individual particle vibrations are transmitted from particle to particle in the direction of wave propagation? There are gaps between particles in solids, liquids and gases. Is this not against principle of locality?
Is wavefunction psi(x) or ket psi same? Or Is it the projection of ket psi on the x basis of a hilbert space is wavefunction psi(x) ?
Mass is a photon of 2pi planck wavelength trapped over own schwartzchild radius.
Gosh...in quark math there is a charge pair "canceling out". What if instead they became a photon, since that's what a photon is. And since they are being create inside a nucleus it must be fairly short wavelength.
m=E/c^2. Mass is energy in orbit.
Gaining angular momentum orbiting a Planck
Yes we want a video
Hi, great video!
I have a question: What exactly is the argument against a particle like an electron is actually spinning? My answer would be that elementary particles don't really have a volume (?) nor a surface which means that you can't determine if it's spinning or not. Is that the ordinary explanation?
I had the same question. Why does P say the particle is not “actually” spinning?
When something spins, parts of an object are revolving around a center. So rotation inherently needs something to be made up from other things. Electrons are not made up of other things.
@@dertechl6628 I agree that the electron is an elementary particle and is not made up of other things, but that does not mean it is infinitesimal. No one knows if the electron has structure, so no one can say that it is not actual rotating.
Ok but what is spin?
Why are there no english words in international Science for so many important values ? Eigen-value..
Hey man, great video! A small issue: I think the σ_y matrix has got its signs flipped. (Also, a request: more fluid mechanics!)
These videos are always great, and really easy to comprehend :) If you're ever looking for video ideas, have you considered creating a series of videos to run through something like the basics of quantum mechanics or general relativity, like the physics version of 3Blue1Brown's "Essence of Calculus/Linear Algebra" series? I know most of that information is already in videos you've made, but it'd be super interesting to see it all laid out in order as a definite series!
One problem for me is, if one says spin is a type of angular momentum shouldn’t there be an associated energy coming with this? But the energy of a particle at rest in vacuum with spin, is just it‘s rest mass(neglecting vacuum fluctuations). I know that the dimension of Spin is the same dimension as angular momentum and it builds the same algebra as angular momentum, but are these the only reasons why one can say it‘s a type of angular momentum?
Let k = h/2pi; Kinetic energy of rotation = p^2/2m, so actually that means this part of any particle's mass-energy is actually just latent angular momentum. You can actually work out exactly what special length you would have to approximate the particle's radius as for this rotational energy to exactly equal the mass energy of the particle: k/l = p; p^2/2m=mc^2; p/sqrt(2) = mc = k/sqrt(2)l; l=k/(mc sqrt(2)), which for particles with masses on the order of 1e-20 kg, this length will be on the order of 1e-12 meters. More precise numbers and considering the inertia of a sphere or a ball will provide various differing answers
@@MrRyanroberson1 Consider that the h bar/square root of [2] is the kinetic constant of any subatomic partcle, I think part of the confusion is that the kinetic value is inherent to the total energy value if the potential energy value is 0 provided the particle is moving through a vacuum.
Just to add, that creates the angular momentum value which is why it is noted as h bar/ square root of 2 as it can be graphed to show its angle given the wave function.
@@Stephanpar23 so you can pick any arbitrary direction and axis you want, so does tbat mean fkr whatever axis you pick the spin will collapse alobg tbat direction, and the wavefunction will collpase to a particle aligned along that axis, I surmise? Is that right?
@@leif1075 Exactly. As the particle is measured, the wave function will collapse into one of two states regardless of where it is measured. This allows us to understand the angular momentum of the particle by deriving the wave function from the Schrodinger Equation.
This derivative will tell us how the particle propagates through space time with respect to the overall kinetic value of the particle and the potential value of the environment set as our operator.
I'm a little uncertain of the operator but I believe it sets the eigenvalue of our function as we obtain the derivative.
Hey, y'all. Physics enthusiast here. I actually read about spin in a text book I bought. So, I'm going to take a crack at the question.
Energy from spin would not contribute to the rest mass, but to the total energy. We have experiments that can identify specific tests masses with great precision with no contribution of any type of momentum (separate discussion). As for spin, we experimentally observe the effects of its magnetic dipole moment when there should be none. For example, sending a beam of electrons through a charged field. If you have the field set so the electrons travel straight through, you will find that they never go straight. They will always go slightly up or slightly down, as if they were spinning charges some with an axis pointing up and some pointing down. No one knows why this happens, but the Dirac and others introduced the math to incorporate this behavior in Quantum Mechanics.
Is there any work done on this which will not describe this in probabilistic way or finding the exact position of a particle before measurement? I mean it does sound a little impossible but still have you come acrossed something like this?
I am fascinated currently with Geometric Algebra
and was thinking that some ideas in that
have been used to encode quantum spin states.
Have you explored those ideas?
What noise does a quantum duck make?
"Quark"
But only if it’s alive when you take it out of the box…
Here comes Schrödinger
I would love to see a video on the derivation of the S operator great video I like when you explain the math and not just the concept
Parth🌟🌟🌟,....If an spin detector DETECTS spin of a neutron.....untill we measure what the spin the DETECTOR HAS DETECTED WAVE FUNCTION DOES NOT COLLAPSE..... RIGHT
WHY DETECTION DOES NOT COLLAPSE THE WAVE FUNCTION....BUT THE MEASUREMENT OF THE DETECTION COLLAPSES THE WAVE FUNCTION....WHY DETECTION IS NOT AN MEASUREMENT?
THANK YOU parth
Dude 😎 dude 😎 ....duuuuuuude I'm learning....that's HUGE
thank you so much
You could argue that a unique one sylllable sound corresponding to the symbol 0 is a necessary condition for evaluating the proposition, 0 is the number "0", as either true, or false, like A is the letter "A", otherwise you're left with an undecideable, Kantian synthetic apriori proposition, where the subject '0' contains the predicate 'is the number zero'.
External magnetic field is a pseudovector. A single test electron inside this field can have two distinct possible relative orientations with respect to the direction of magnetic pseudovector. So an aparatus for determining electron spin is using magnetic field. Is there in theory a way to measure spin using gravitational field?
what if e- spin cuz of its composition ie the quarks since they r born with quarks they spin from there birth
2 up and a down which forces the e- to rotate
missing so much the background and the Guitar,,,
8:42... Small typo - in the last term, i should be in numerator.
Kind of reminds me this video: ua-cam.com/video/PkYJAZqzjhU/v-deo.html
I want to see you derive the Pauli Matrices
Would love for all those extra derivations in another video :)
You need Lie group and Lie algebra
We would like to see it sir pls❤
7:36 yes pleaseee
nothing you tell.
Are you indian ?
Please do!
Thanks
Electrons have mass, could that mean that they also have some (even if tiny) volume after all and that physical spin operates in that volume? Just wondering...
I’d like more on the three spin states of photons. I thought they only had two.
Just wanted to say I appreciated the quantum spin Maybelline joke 😁
Keep up the good work. Hope someday I'll be able to understand this shit ✊🏽❤️
Hey Parth,
Thank you so much for your content. It isn't easy to get along channels on youtube that give mathematical intuition about the physics discussed but still in a fun and interesting way. You really make that work. Keep it going and have a great end of the year and a great start into the new year
Cheers
I conceive it as spikes in all directions from a point, being outward force or inward force, and therefore, positive➕ or negative.
Spin states are Levo or Dextro due to deflection.
Great video! If someone is more interested in how the spin was discovered you can read about the Stern-Gerlach experiment.
I loved your video , But please make a video on the Dirac equation.
its a good idea to make a video deriving the matrices
Nice job ! Thanks a lot !
absolutely amazing
Here first ❤️🙏👍
Actually its parth himself XD
@@arthtiwari3232 got you 👍