couldnt be more thankful! thank you soooo much! My homework problems are so much more easier to solve after watching your lecture Prof! Stellar! Anyone taking QM should watch these lectures!
we see that at 35:40 Sir did (psi*)(x)(psi) zero at infinity, but when psi tends to zero, x is also tending to infinity so isn't this making a 0*infinity form which is indeterminate?
No actually Thats not as you thought Particle is locallized some where in space. x will never go to infinity( Actual speaking infinity is nothing but you can say x is very much larger.)
@@subhrajitbiswas5829 but the function is not zeto, it TENDS to zero. And x tends to infinity. So, his point is right. But, I think that psi tends to zero faster that x tends to infinity, because it has exponential form.
Thank you very much. I have a question though, I get that psi multiplied by its conjugate is the modulus of psi squared, but failed to see why the operator only operates on psi. Sorry if this is a trivial question
@Tristan Lee I think I got u a little , it is operable on any wave function not only on specific psi, also psi here is itself any wave function. So when any conjugate is multiplied by itself you'll get mod psi squared dx. Sorry if this was not you were asking for.
There I find a confusion in the proof of Schwarz's inequality because of the greater than equal sign used there. It's rather helpful: th-cam.com/video/FdduPqpTLAY/w-d-xo.html
When the teacher proved uncertainty principle from Schwarz inequality, in the last step he took root over h cross/4 and got h cross/2. But shouldn't the result be √h cross/2 ???
Sir i am having two doubt 1. During the proof of Schwartz inequality there was no equal sign but u put greater than and equal sign why is it? 2 when you proof uncertainty principle from Schwarz inequality in rhs there was h cross only and when we took the root over it should become root over of h cross.
No, because he calculated only (fg*+f*g)/4 and he got h-cross/4. The inequality says that (f*f)(g*g) > (fg*+f*g)²/4 under integration. So, (f*f)(g*g) > (h-cross)²/4. Taking sqrt, e=you get only h-cross/2.
These lectures are pure gold!!
couldnt be more thankful! thank you soooo much! My homework problems are so much more easier to solve after watching your lecture Prof! Stellar! Anyone taking QM should watch these lectures!
By learning through your teaching I could understand quantum mechanics book written by Schiff. Stanford University.Thank you great professor.
Superb...make the concept crystal clear....continue it for other subjects
such a life saver...
we see that at 35:40 Sir did (psi*)(x)(psi) zero at infinity, but when psi tends to zero, x is also tending to infinity so isn't this making a 0*infinity form which is indeterminate?
Zero multiple by any thing gives you zero
@@santanusingh4669 but bro 0 multiplied by infinity is an indeterminate form
No zero multiplied by infinity is zero!!
No actually
Thats not as you thought
Particle is locallized some where in space.
x will never go to infinity( Actual speaking infinity is nothing but you can say x is very much larger.)
@@subhrajitbiswas5829 but the function is not zeto, it TENDS to zero. And x tends to infinity. So, his point is right. But, I think that psi tends to zero faster that x tends to infinity, because it has exponential form.
Really great lectures thank you.
Thank you so much sir ☺️☺️☺️
Why f() and g() are assumed as such to derive uncertainty principle?
Special case as there are many observable quantities which do not commute ∆p and∆x such a type of example
Except Thanks what shall give you?Giant of physics.
Thank you very much. I have a question though, I get that psi multiplied by its conjugate is the modulus of psi squared, but failed to see why the operator only operates on psi. Sorry if this is a trivial question
Doesn't get you...will you elaborate
@Tristan Lee
I think I got u a little , it is operable on any wave function not only on specific psi, also psi here is itself any wave function. So when any conjugate is multiplied by itself you'll get mod psi squared dx. Sorry if this was not you were asking for.
these lectures are so good! I hope they prepare lecture on every topic in physics.
In last example how can we get a(p) ?
sorry but the great ajoy missed one equality sign at 20:11
Check this out:
th-cam.com/video/FdduPqpTLAY/w-d-xo.html
There I find a confusion in the proof of Schwarz's inequality because of the greater than equal sign used there.
It's rather helpful:
th-cam.com/video/FdduPqpTLAY/w-d-xo.html
When the teacher proved uncertainty principle from Schwarz inequality, in the last step he took root over h cross/4 and got h cross/2. But shouldn't the result be √h cross/2 ???
@@blzKrg because he forget to square h cross
Sir i am having two doubt
1. During the proof of Schwartz inequality there was no equal sign but u put greater than and equal sign why is it?
2 when you proof uncertainty principle from Schwarz inequality in rhs there was h cross only and when we took the root over it should become root over of h cross.
Exactly. The 2nd doubt is also my doubt.
Actually it will be (h-cross)^2/4
he forgot put the square over the integral part
he was right, i have checked it
You should add the equal sign. Uncertainty says delta x × delta p >= h-cross/2
No, because he calculated only (fg*+f*g)/4 and he got h-cross/4. The inequality says that (f*f)(g*g) > (fg*+f*g)²/4 under integration. So, (f*f)(g*g) > (h-cross)²/4. Taking sqrt, e=you get only h-cross/2.