First one I think just means the expected value of x. Since the integral would be psi star * x * psi over the domain and that is what means. (I'm not sure exactly what he is looking for here) Second one would be zero. This is because states of the QHO are a orthogonal basis. X hat is hermitian because xhat = x and it is a real number and therefore it is commutative so =int( psi star * x * psi ) = int(x *psi star * psi) = * means multiplication not star
But wouldn't the (impulse) operator still be hermitian without the minus? You wouldn't have a minus at the end, but you would also not need one? Or more general, I would say that for a hermitian operator A -A is also hermitian (because =-=-=)
ummmmmmmmmm... im trying to find out wtf this guy is talking about, I can do things like calculus, but this, this just gets complicated, and I wanna know how to actually use this, and calculate something out of it, and properly use this.
Well then you'll need to do atleast a bachelor's in physics. For quantum mechanics first learn linear algebra, fourier transforms and special functions (Mary Boas' book is great for this)[you should also learn how to solve differential equations; partial differential equations are a bonus] . Then start with Quantum Mechanics by David Griffiths which is what this guy is following. Also the math used here is not complicated, if you are comfortable with calculus upto calculus 3 and linear algebra then this math is trivial.
The definition of variance in statistics is (X−⟨X⟩)^2 which can be written as ⟨X^2⟩−⟨X⟩^2. This relates to QM with (Q−⟨Q⟩)^2 and in its expanded form is (Q−⟨Q⟩)(Q−⟨Q⟩) = Q^2−2⟨Q⟩Q+⟨Q⟩^2 . Meaning ⟨ψ|Q^2|ψ⟩^2 − 2⟨Q⟩⟨ψ|Q|ψ⟩ + ⟨Q⟩^2. This simplifies to ⟨Q^2⟩ - ⟨Q⟩^2 as -2⟨Q⟩⟨ψ|Q|ψ⟩ = -2⟨Q⟩^2.
It is now 2024... I already forgot how much difference you can feel between 480p and 720p. This video is much sharper than the previous one.
very good content sir. thank you .. sir kindly make a video on Bound
States for Potential Wells with no rigid walls.(wkb approximation )
on the second page, there is a small typo. you said sqrt{n} but wrote down sqrt{2} on the denominator
A hilbert space can be finite dimensional
Informative and enlightening
You read my mind regarding uncertainty principle......
Thanks for these videos
Really helped a lot
Isn't it the coolest thing ever 🤗 ??( Me pretending i understand something in this LABYRINTH )
At 17:40 integration by parts is uv-integral(v*du). Why would you put du*v?
Can anybody explain check your understanding problem?
First one I think just means the expected value of x. Since the integral would be psi star * x * psi over the domain and that is what means. (I'm not sure exactly what he is looking for here)
Second one would be zero. This is because states of the QHO are a orthogonal basis.
X hat is hermitian because xhat = x and it is a real number and therefore it is commutative so =int( psi star * x * psi ) = int(x *psi star * psi) =
* means multiplication not star
really helpful, thanks
But wouldn't the (impulse) operator still be hermitian without the minus? You wouldn't have a minus at the end, but you would also not need one? Or more general, I would say that for a hermitian operator A -A is also hermitian (because =-=-=)
thaks this is helpful. I love you
Thank you
Thanks 💜💜
Thanks sir
Because i have an IQ of 23, does this video include determinate states?
EDIT: I'm sorry I am so dumb I just found It
But can it run X
Nice
The way you did the momentum operator example is not great for those us attempting to follow what you did., please consult the Griffiths book
wat
Who would dislike wth?
Wtf im just 8th grade and i just understand a bit of this.
SunDarating am just 2 grade
I'm first grade and I'm already at Phd level
O. G Austin Am owen a lott of besnisis. Am new stev job.
@@milk9613 I am become death, the destroyer of worlds
ummmmmmmmmm... im trying to find out wtf this guy is talking about, I can do things like calculus, but this, this just gets complicated, and I wanna know how to actually use this, and calculate something out of it, and properly use this.
Well then you'll need to do atleast a bachelor's in physics. For quantum mechanics first learn linear algebra, fourier transforms and special functions (Mary Boas' book is great for this)[you should also learn how to solve differential equations; partial differential equations are a bonus] . Then start with Quantum Mechanics by David Griffiths which is what this guy is following. Also the math used here is not complicated, if you are comfortable with calculus upto calculus 3 and linear algebra then this math is trivial.
You can watch his earlier videos and also read the book "Introduction to Quantum Mechanics" by David Griffiths which he is following
brain hurtie
Just copy pasted griifiths, you totally made a mess of the standard deviation formula.
Came here to understand it. YOU FAILED SUCCESSFULLY.
Completely agree with you !
he pretends to explain everything but he's actually failing
To explain anything in a coherent manner
The definition of variance in statistics is (X−⟨X⟩)^2 which can be written as ⟨X^2⟩−⟨X⟩^2. This relates to QM with (Q−⟨Q⟩)^2 and in its expanded form is (Q−⟨Q⟩)(Q−⟨Q⟩) = Q^2−2⟨Q⟩Q+⟨Q⟩^2 . Meaning ⟨ψ|Q^2|ψ⟩^2 − 2⟨Q⟩⟨ψ|Q|ψ⟩ + ⟨Q⟩^2. This simplifies to ⟨Q^2⟩ - ⟨Q⟩^2 as -2⟨Q⟩⟨ψ|Q|ψ⟩ = -2⟨Q⟩^2.
an inappropriate way of teaching some concepts