David Bowler (Million Atom Man)

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@MillionAtomMan 23 күн бұрын

At around 10 minutes there is a typo: the transform for t' should have c in the denominator, not c squared.

@JohnSmalls-r9i 2 ай бұрын

Ernser Squares

@mohtasimtamjeed 3 ай бұрын

for the divergence of a curl those should be del squared terms?

@nicolabellemo3054 6 ай бұрын

wonderful

@karljager1941 8 ай бұрын

For a plane wave in the z direction you shouldn't have a T_xx or T_yy component, because the electric and magnetic contributions cancel each other exactly out

@ashishbhargavkalita2013 8 ай бұрын

sir what does R indicates

@mohtasimtamjeed 7 ай бұрын

R is the Lorentz Transform

@ashishbhargavkalita2013 8 ай бұрын

sir shouldn't the indices of F in electromagnetic field tensor be down due to contravariant formulation.

@muaazshanji1066 8 ай бұрын

Absolutely class, deserves a standing ovation

@leighton9113 8 ай бұрын

😕 P R O M O S M

@ceren7289 11 ай бұрын

Great explanation, the logic is very clear

@AMU964 11 ай бұрын

Thanks a lot sir

@verite44 Жыл бұрын

Awesome

@roatninthethird Жыл бұрын

hey man, im really bad at math but this was pretty cool even if i have 0 idea what it means

@asrbasit Жыл бұрын

Very informative

@jacobvandijk6525 4 жыл бұрын

Hi David. Thanks for the video! You wrote < x | psi > = psi(x). But how could the ket-vector psi exist (before it was hit by x), if it wasn't in any basis?

@swastusrinix 4 жыл бұрын

Do you have matlab code for second order perturbation theory?

@sayanjitb 4 жыл бұрын

Dear sir, what do those eigenvalues and eigenvectors of operators a_^ & a+^ mean physically in QHO scenario? Could you please shed light on it!

@jomen112 4 жыл бұрын

Can we from matrices mechanics infer what the math might represent, such as is sometimes done within wave meachanics?

@rosiesocial 5 жыл бұрын

Thanks

@AshokKumar-sq1no 5 жыл бұрын

@岡安一壽-g2y 5 жыл бұрын

Hello, sir. ! Generally, the anti-symmetric wave function is not the eigenfunction of the system. Example. Please suppose the system composed of two electrons. Electron 1 is in a hydrogen atom. Electron 2 is in a helium ion He+. rA, rB:the position of each nucleus. ❘rA-rB❘>>1. H1=(p1^2/2m)-(e^2/4πε0❘r1-rA❘), H2=(p2^2/2m)-(2e^2/4πε0❘r2-rB❘), H1φA(r1)=EAφA(r1), H2φB(r2)=EBφB(r2). Hartree productφA(r1)φB(r2) is the eigenfunction of operator H1+H2, and lead us the energy of the system EA+EB. But, another productφA(r2)φB(r1) is not the eigenfunction of operator H1+H2. (Please calculate it. It's very easy.) Therefore, the anti-symmetric wave function ψ=φA(r1)φB(r2)-φA(r2)φB(r1) is not the eigenfunction of the system.

@kzalesak4 5 жыл бұрын

Thank you for making these videos!

@erikhendrych190 6 жыл бұрын

<x|psi>=psi(x) ... I know why this is valid in the particular case. However I don't understand why is it possible to assign state vector to a coordinate. What exactly is <x| and under what conditions does the equation hold? Thanks P.S. I don't mean to sound rude. Just asking because I am kinda lost in bra-ket notation.

@jacobvandijk6525 4 жыл бұрын

You are not the only one. Think of the general function y = f(x). Now, in QM EVERY FUNCTION IS A MACHINE THAT SWALLOWS A BASISVECTOR (x) AND SPITS OUT A COMPONENT (y). That can only happen when the machine is a vector! You need the scalar-product for that. When V = x . i + y . j + z . k, then j . V = y. Here V = f(x).

@Achrononmaster 4 жыл бұрын

Erik, just think of |x> as the state of “the particle is at position x”. The position coordinate in the ket is just a label, a shorthand. Then bra <x| is just the Hermitian conjugate of that state. What then is a “Hermitian conjugate”? Physically it is a lot like a “time reverse” of the state. The maths will not tell you this, but that is what it amount to in physics usage If the state is not time dependent then the bra vector is just a vector space dual, which is useful for forming inner products when needed, e.g., for measurement projection onto that state. So <x|y> is the projection of state |y> onto state |x> (in linear algebra jargon), equivalently the amplitude for transition from |y> to |x> (in physics jargon)..

@erikhendrych190 4 жыл бұрын

@@Achrononmaster Thanks. :)

@ignaciomartinalliati6293 6 жыл бұрын

5:25 I have some concerns about what follows from there... that double sum gives me the idea of a nxn matrix, while a bra-ket is a number, as you say. Couldn't we just say that a bra is a row vector (1xn) and a ket is a column vector? Hence, a bra-ket would be a number (1x1 matrix)? In that case then, you wouldn't need the basis to be orthonormal, but only normalised, would you? Is this correct? The result is the same though.. Thanks!

@doc_lenz 7 жыл бұрын

Very useful thanks, I didn't get the convention of decreasing eigenvalues so at first time I didn't understand the matrix

@Ovechkin8484 7 жыл бұрын

Why is S = < x | phi > ? Doesn't an inner product return a scalar quantity instead of a matrix?

@MillionAtomMan 7 жыл бұрын

You'll notice that all these have subscripts: S_{ki} for instance. An inner product does indeed return a scalar - and each inner product (scalar) forms an element of the matrix S.

@matthewsarsam8920 7 ай бұрын

Super late answer but each column of S should be the representation of the phi basis ket in terms of the x basis kets, and the representation is a column vector with scalars representing how much of each basis ket in the x basis needs to contribute to form the psi basis ket

@progress1994 7 жыл бұрын

I really wish just one of these lecturers on quantum notation would use numbers instead of just writing pure theory on the board.

@huzayfah 8 жыл бұрын

This video taught me more about SHM than 4 hours worth of mechanics lectures

@أزهارالحوامدة 8 жыл бұрын

thx ser

@poopzassshit 8 жыл бұрын

Im taking an atomic physics course. and your video was the first time these matrices made sense to me! Thank you!

@armalify 8 жыл бұрын

Hi David, Could you please tell me which book do you use or recommend for clear understanding of Q.M. ? There are many and many books and textbooks on Q.M. I came across but still they don't take you step by step to the quantum world!!

@MillionAtomMan 8 жыл бұрын

I can't recommend one - I have used many. Personally, I like Dirac's Principles of QM, and have used/read mainly Bransden & Joachim and Gasiorowicz.

@mohammedviso2269 8 жыл бұрын

Thank you so much for this