Thanks. I welcome corrections. It's easy to make a slip of the tongue so it's very helpful when people point it out so I can make an annotated correction.
I am currently in High school and although your videos are sometimes hard to understand for me, I love them. I can't wait to finally start studying physics. Your videos might even help me with that. So, thanks!
Absolutely amazing video, I'm not a physics or mathematics student, so many more technical videos on quantum physics are too hard to understand for me but I want to learn it. These detailed explanations are great, and you make it especially easy to follow!
only scientists who really understand the subject can represent physics into mathematics and back. this is the ultimate skill! what a wonderful people...
Brilliant and very clear. Thanks for the efforts put in it, which must be huge, because not many understand the subject or explain it so well.. Thanks again.
There are alot of things to remember in this video which haven't been mention in part 1 but are spread into particles in dozens of videos whose right order is a mystery. It is very helpful then that the calculations are done with double speed.
Welcome to SimpleScience! Our very new Educational UA-cam Channel. On here you will get to cover all sorts of science topics ranging from Biology, to Chemistry and to Physics in SIMPLE and SHORT and EXTREMELY INFORMATIVE videos from our experts! Please come and watch our channel!
well... then i'll proceed to theory of matrix mechanics :) yet - it will no way hamper my intensifying deepening into fourier )) i really like it !! WOW ! and thank you sir ! )
Not for the approach that I am taking, but it is worth having some understanding of Fourier transforms because it is essentially the use which transform momentum wave functions into position wave functions.
if k and p are quantized, wouldnt it imply that velocity must be quantized as well? If so, there seems to be no way to understand how a particle can accelerate from 0 to 1 quantum of speed as it would involve division by zero (squared)?
I have a weird idea now. What I interpreted from this is that whenever our physical body moves through spacetime, the particles that make up our body is continuously being annihilated then created. It's just that, what the particles in our body is in collision with?
thanks for giving me a way to approach the operators. my weakness in that area was making string theory a bit difficult. if you did one on langrangians that would be splendid as well..:)
Dr physic or some one read these, please answer my quation, I'm student of mathematic in bachelor degree. and I want to make essay about physic for my thesis. in dirac equation moment you put mass, you said when we deal with wave move to right we will got mass terms move to left and vice versa. can you give the example about this statement, I mean not about mathematical proove but axample in quantum mechanic or particle physics, what precisely these maen? tankyou
Partial derivatives simply indicate that there is more than one variable in the equation and that you are differentiating only with respect to one of them.
Wow, that was intense. Another great vid. There was so much poured on at the end there that I was left wondering what it all means. I understand the math but I'm not sure how it all relates to mass and spin and etc, etc. I suppose (hope) that's coming up. Also, is the wave equation you used here the same one that you used for the Maxwell's light video? That one used second derivatives? Thanks again for a good ride!
Another excellent video. So, is it reasonable to say that a particle represented by a "complete" right-moving wave is the sum of a right-moving "non-mass" wave traveling at the speed of light, and a left-moving "mass-related" wave moving at a speed less than the speed of light such that the sum of these two waves results in a "complete" right-moving wave? And, the larger the mass, the faster the left-moving "mass-related" part of the "complete" wave?
Leading into the 19 min mark, why is it a+a+a- rather than a+a- + a+a-, ala (a+ + a+)a-? As written, it seems the first a+a- creates k2, so the second a+ is acting on k2 (without annihilating it first) to create k3, and not the annihilated k1.
The basic mathematical formulation of Fourier series is relatively easy to learn, all you need to know is calculus to decent degree and basics of complex numbers. If you need a good book covering mathematical topics used by physicists try Mathematical methods in the physical sciences by Mary L. Boas.
Congratulation for this again amazing video. At 25minutes, you explain that tha only one electron can have a certain value of k, is that mean that each k value represent an orbital ?
Quick question: If there are two electrons (e and f for clarification), where e is at state A and f is at state A + 1, what happens if a photon (or another boson) hits e with enough energy to promote it? Will it pass through the state A + 1, breaking the Pauli exclusion principle (if only temporarily), instantly jump to its new energy level, or would it just be physically impossible for the photon to hit e because f is the highest energy level?
Pauli's principle always applies. So if an electron gets enough energy to be promoted to a level which is already full then the electron cannot be promoted.
At 8'30'' you state that a plus acting backwards (on a bra vector) annihilates. You said this was shown in the previous video. Please can you show where or explain the maths. Thanks
mynyddwrglas Acting backwards is analogous to acting the Hermitian conjugate of the operator in the forward direction. The conjugate of the creation operator is the annihilator. What I don't get is that shouldn't that flip the signs of k2 and k3 in the exponentials?
37:39 You said Fermi but you mean Dirac. Based off your other videos, I figure you'd want this correction, so I hope this doesn't come across as nitpicking. Anyway, I've really been liking these series. Thank you very much for putting them out.
how about dimensions in the Dirac equation, the right and left side are different, the left side you add mass multiplied by a wave function, while the left only energy. you got wrong in dimension so the equation cant be use
May I ask you guys something? So, I don’t know much about physics, but I’m planning a WEBTOON and I wanna make it about these two people...one is able to create energy and another one destroys it I KNOW YOU CANNOT MAKE ENERGY OR DESTROY IT, OK, BUT IT’S FICTION So...I figured the person who destroyed energy could make things levitate (destroying the force of gravity) and freeze things (destroy kinetic energy), but Idk what other powers I could come up with And I have no idea what energy creation could bring, I suppose you could make things move to your wish by creating force on them and you could melt stuff but Idk And what could they do together???
I was searching the comments to see if anyone else caught this. Physicists have a tendency to hand wave things as long as it leads them to an conclusion they happen to know is still correct. It's confusing, I never know whether to trust it or not.
That is just the classical, non-quantised one dimensional wave equation, except square rooted. The actual equation is d²ψ/dt² = -v² d²ψ/dx². This works for all waves. But, the dψ/dt = -v dψ/dx equation works only for functions in the form e^i(kx - wt) and not trigonometric functions.
so around 11:00 we see that integral dt of e^(i (omegaF-omegaI)t) is Kroenecker Delta * t? Because if omegaF=omegaI you would just integrate 1*dt so that's t. So if you would go on and measure the probability of that scattering, at around 12:00 you would get = a probability of t^2. That makes no sense.
Around minute 44, you find w^2 = a^2 * k^2 but you previously put v = 1 whereas v = w / k. Without this assumption, you would have w^2 = w^2 ... I'm not sure of what this part shows ...
The GCSE playlist is for students aged about 16, the A Level playlist is for students aged about 18, the rest are probably covered at university first degree level.
Thanks. I welcome corrections. It's easy to make a slip of the tongue so it's very helpful when people point it out so I can make an annotated correction.
Thank you for going through the trouble to make these videos for us
I am currently in High school and although your videos are sometimes hard to understand for me, I love them. I can't wait to finally start studying physics. Your videos might even help me with that. So, thanks!
Absolutely amazing video, I'm not a physics or mathematics student, so many more technical videos on quantum physics are too hard to understand for me but I want to learn it. These detailed explanations are great, and you make it especially easy to follow!
"Sorry Paul, you can't do that"
But Paul Dirac is unpertubed.
:D
"You can't sit with us!"
-Wolfgang Pauli
Hello paul
only scientists who really understand the subject can represent physics into mathematics and back. this is the ultimate skill! what a wonderful people...
Thanks for your videos! Clear and concise. A joy to watch. I wish I had you as a professor.
Brilliant and very clear. Thanks for the efforts put in it, which must be huge, because not many understand the subject or explain it so well.. Thanks again.
So this is the video that derives dirac equation. But it is done in terms of angular speed and wave number. Refreshing
these videos are so, so good. and it really is fkn incredible that in a few thousand years we've gone from counting bushels of wheat to.... this 😮
i love this!
Thank You!!
There are alot of things to remember in this video which haven't been mention in part 1 but are spread into particles in dozens of videos whose right order is a mystery. It is very helpful then that the calculations are done with double speed.
You, sir, deserve a medal!
He's got one :)
1:02:47 being in 3 dimensions shouldn't the derivative of psi to be in the direction? so dx_j if you call x the quadrivector of spacetime components?
Greatjob very helpful
This is joy!
Welcome to SimpleScience! Our very new Educational UA-cam Channel. On here you will get to cover all sorts of science topics ranging from Biology, to Chemistry and to Physics in SIMPLE and SHORT and EXTREMELY INFORMATIVE videos from our experts! Please come and watch our channel!
thank you very much sir
great job
well... then i'll proceed to theory of matrix mechanics :)
yet - it will no way hamper my intensifying deepening into fourier )) i really like it !! WOW !
and thank you sir ! )
Not for the approach that I am taking, but it is worth having some understanding of Fourier transforms because it is essentially the use which transform momentum wave functions into position wave functions.
Why at 23:42 we are not including the potential energy? Please clarify
if k and p are quantized, wouldnt it imply that velocity must be quantized as well? If so, there seems to be no way to understand how a particle can accelerate from 0 to 1 quantum of speed as it would involve division by zero (squared)?
doc, thank you guy.
you are answering almost all my questions. but what i am lacking is experiments.
thank you very much - 've just got it ! ))
interesting indeed :)
can you propose any books for quantum field theory or any lectures notes ?
I love his brain.
I have a weird idea now. What I interpreted from this is that whenever our physical body moves through spacetime, the particles that make up our body is continuously being annihilated then created. It's just that, what the particles in our body is in collision with?
”It just travels at the speed of time through time...” Mind = blown
thanks for giving me a way to approach the operators. my weakness in that area was making string theory a bit difficult. if you did one on langrangians that would be splendid as well..:)
There is something along these lines in my video on analytical mechanics.
Dr physic or some one read these, please answer my quation, I'm student of mathematic in bachelor degree. and I want to make essay about physic for my thesis. in dirac equation moment you put mass, you said when we deal with wave move to right we will got mass terms move to left and vice versa. can you give the example about this statement, I mean not about mathematical proove but axample in quantum mechanic or particle physics, what precisely these maen? tankyou
Partial derivatives simply indicate that there is more than one variable in the equation and that you are differentiating only with respect to one of them.
Wow, that was intense. Another great vid. There was so much poured on at the end there that I was left wondering what it all means. I understand the math but I'm not sure how it all relates to mass and spin and etc, etc. I suppose (hope) that's coming up. Also, is the wave equation you used here the same one that you used for the Maxwell's light video? That one used second derivatives? Thanks again for a good ride!
How can you assume velocity = 1 and c = 1 simultaneously for that particle. Isn't that wrong?
I think it would be if it is a photon, which it’s velocity would = c
At 18 , presumably the "bra" zero ground state would be identified by the two particle .
So is the inner product of still 1?
I like this video.
Another excellent video. So, is it reasonable to say that a particle represented by a "complete" right-moving wave is the sum of a right-moving "non-mass" wave traveling at the speed of light, and a left-moving "mass-related" wave moving at a speed less than the speed of light such that the sum of these two waves results in a "complete" right-moving wave? And, the larger the mass, the faster the left-moving "mass-related" part of the "complete" wave?
Leading into the 19 min mark, why is it a+a+a- rather than a+a- + a+a-, ala (a+ + a+)a-? As written, it seems the first a+a- creates k2, so the second a+ is acting on k2 (without annihilating it first) to create k3, and not the annihilated k1.
Great!
can you plz do some examples at the wave equation
The basic mathematical formulation of Fourier series is relatively easy to learn, all you need to know is calculus to decent degree and basics of complex numbers.
If you need a good book covering mathematical topics used by physicists try Mathematical methods in the physical sciences by Mary L. Boas.
Congratulation for this again amazing video. At 25minutes, you explain that tha only one electron can have a certain value of k, is that mean that each k value represent an orbital ?
Is the integral over time at 5:15 a superposition of states?
Quick question: If there are two electrons (e and f for clarification), where e is at state A and f is at state A + 1, what happens if a photon (or another boson) hits e with enough energy to promote it? Will it pass through the state A + 1, breaking the Pauli exclusion principle (if only temporarily), instantly jump to its new energy level, or would it just be physically impossible for the photon to hit e because f is the highest energy level?
Pauli's principle always applies. So if an electron gets enough energy to be promoted to a level which is already full then the electron cannot be promoted.
So, in the case where e would get promoted to an energy level above f, it would just instantly jump to the new level?
At 8'30'' you state that a plus acting backwards (on a bra vector) annihilates. You said this was shown in the previous video. Please can you show where or explain the maths. Thanks
mynyddwrglas Acting backwards is analogous to acting the Hermitian conjugate of the operator in the forward direction. The conjugate of the creation operator is the annihilator. What I don't get is that shouldn't that flip the signs of k2 and k3 in the exponentials?
Did you make the video about spontanious symmetry breaking?
37:39 You said Fermi but you mean Dirac. Based off your other videos, I figure you'd want this correction, so I hope this doesn't come across as nitpicking.
Anyway, I've really been liking these series. Thank you very much for putting them out.
When you put it on x2, he sounds like he's on crack! But very good lecture! Keep up the good work!
tell me please sir - to understand this brain-crushing formulae should i before to know at least Fourier series or the like ? :)
as the k-psi go rolling along!
how about dimensions in the Dirac equation, the right and left side are different, the left side you add mass multiplied by a wave function, while the left only energy. you got wrong in dimension so the equation cant be use
i copy all this down for my class. thank you
May I ask you guys something?
So, I don’t know much about physics, but I’m planning a WEBTOON and I wanna make it about these two people...one is able to create energy and another one destroys it
I KNOW YOU CANNOT MAKE ENERGY OR DESTROY IT, OK, BUT IT’S FICTION
So...I figured the person who destroyed energy could make things levitate (destroying the force of gravity) and freeze things (destroy kinetic energy), but Idk what other powers I could come up with
And I have no idea what energy creation could bring, I suppose you could make things move to your wish by creating force on them and you could melt stuff but Idk
And what could they do together???
@@annymus4502 dawg i have no idea what u said i literally commented this like 4 years ago and pretended to know what it means LMAO
@@RishiKumar-zm6nv
Don’t worry then
Have a nice day!
You sir, have a new subscriber. Just a quick clarification: Your final 3-D Dirac equation should be dPsi/dj (not dx), correct? Wonderful videos.
at 44.00 you say that omega = plus/minus alfa times k. But omega and k are scalars, alfa is a matrix. Maybi I miss something?
I was searching the comments to see if anyone else caught this. Physicists have a tendency to hand wave things as long as it leads them to an conclusion they happen to know is still correct. It's confusing, I never know whether to trust it or not.
15:53 That acts on the state K1 not state Ki
You derive a wave equation: dψ/dt = -v dψ/dx. What is this wave equation called?
That is just the classical, non-quantised one dimensional wave equation, except square rooted. The actual equation is d²ψ/dt² = -v² d²ψ/dx². This works for all waves. But, the dψ/dt = -v dψ/dx equation works only for functions in the form e^i(kx - wt) and not trigonometric functions.
so around 11:00 we see that integral dt of e^(i (omegaF-omegaI)t) is Kroenecker Delta * t? Because if omegaF=omegaI you would just integrate 1*dt so that's t. So if you would go on and measure the probability of that scattering, at around 12:00 you would get = a probability of t^2. That makes no sense.
Please help me see what I'm missing! Thank you :(
I wonder if in high school you were that much into physics...did you get into advanced physics before or after high school?
are there lecture notes available
Around minute 44, you find w^2 = a^2 * k^2 but you previously put v = 1 whereas v = w / k. Without this assumption, you would have w^2 = w^2 ... I'm not sure of what this part shows ...
Another question Bob: I notice the Dirac equation is typically given with partial derivatives, why so? And does it make any difference?
are your lectures are same as that of phd lectures
The GCSE playlist is for students aged about 16, the A Level playlist is for students aged about 18, the rest are probably covered at university first degree level.
does it bug anyone else that he says "beetah"instead of "baytah"
"
at first now i say it too
no