L2.2 Anharmonic Oscillator via a quartic perturbation

[@cristivoinea8742]

If you watch his lectures on 1.5x they're actually pretty good

[@lakhan7179]

👌👍

[@meghamanihaldar648]

Hey.... i do this🤭🤭... sir is awesome

[@meetghelani5222]

Oh yes, doing the same.

[@not_amanullah]

2x

[@helloby4125]

Watching this after Watching bender's lectures gives you the feeling of standing on the shoulders of giants

[@meghamanihaldar648]

Sir it's my humble request to make videos on the course of relativistic quantum mechanics..... your lecture is awesome sir..just awesome .....its my request to mit.... it'll help a lot

[@shivammishra6624]

Yeah same , needed that one

[@not_amanullah]

Thanks 🤍❤️

[@cngrinder9423]

Can someone please explain me why he gets these results when doing bra(0) (a+a dagger)^4 ket(k) or ket(0)? I don't understand it

[@MrFuncti0n]

for bra(0)(a+a dagger)^4 ket(0), expand out (a+a dagger)^4, noting that a and a dagger do not commute. Then, apply this expansion to the state ket(0) -- you will find only the contributions a*adagger*a*a dagger and a^2*a dagger^2 put between bra(0) and ket(0) will give a nonzero result, as the other terms will either annihilate the ground state or be orthogonal (e.g., bra(0)ket(2) = 0). Similar considerations apply to other matrix elements.

[@prabhatp654]

Why this argument of asymptomatic expansion is justifiable? If it's an infinite sum, it says that for any value of lambda, your ground state energy will be infinite? Doesn't it mean that the assumptions (of series expansion) you took, in the beginning, are false? What is happening?

[@JohnVKaravitis]

1:30 Then the dotted line s/b inside the parabola. 17:20 Please close your parenthesis.

[@Cienciasexy]

Not for x

[@cikif]

13:41 he says "the bra"

[@bonnome2]

What is your point? He is talking about the bra + operators he underlined on the previous board.

[@cikif]

so that whoever is in charge of adding subtitles can fix it

[@c8adec]

He actually says "the bruh", a physics term

[@Skumar-rg4hd]

Yes it is clearly "bra" came from bracket

[@DragonWarrior1524]

No it's Cali dialect for "the brah", like his homies

[@bonnome2]

Could you please make an better title? It can be really unclear from the title what the previous lecture is.

[@ankykolo6526]

The worst lecture I have ever seen. Congratulations MIT !. This guy isn't even teaching, he is just talking to himself. LOOOOL

[@bonnome2]

Some forms of lecturing are better for some than others. Most people find him pretty good.

[@danielgeorge7466]

You're kidding, right?

[@lobisw]

I learnt plenty from this, so it can't be that bad. Plus I've been to some shocking lectures. So it must at least be decent.

[@isaacwesterback9127]

ahh yess he should def be having an open class discussion for QM with undergrads im sure they would learn wayyy more lmao /s

[@dsanjoy]

It's lecture 2.2 of QM-III and he is trying to demonstrate how to use the perturbation technique to approximately solve an unsolvable problem. What did you expect? Some pop-science s**t ?