It would have been very difficult to jump start my my self learning QM using Griffith's book if had not found your videos. Thanks for making these videos.This was just what I needed.
@rashidalali65103 жыл бұрын
What a coincidence, I also came here because of Griffith
@ahmed24-z2b9 ай бұрын
and same here
@Peter_19862 ай бұрын
A lot of physics books have an irritating tendency to go on forever about a million different things at the same time, so that it takes a very long time to read them. Video tutorials tend to be much more straightforward and to the point.
@riosvm11 жыл бұрын
Best explanation of wave function normalization on KZbin.
@sphericalchicken11 жыл бұрын
No real magic there... 1/i is equal to -i. You can see that starting with i^2 = -1. Dividing both sides by i should give you i = -1/i, so multiplying both sides by -1 gives you -i = 1/i. It's handy sometimes to move i to the numerator, so I've made that 1/i --> -i conversion.
@mikevaldez76845 жыл бұрын
An Excellent exposition of Griffth's much abbreviated proof in chapter 1 of the 2nd ed.
@sphericalchicken11 жыл бұрын
It's worse than that, actually -- Psi(x) can be positive or negative, and can even by complex. The missing piece is that Psi (the wavefunction) is not itself the probability density. Instead, we treat |Psi(x)|^2, the squared absolute magnitude of Psi(x), as the probability density, and |Psi(x)|^2 is always a positive real number.
@genekisayan6564 Жыл бұрын
hey, could you explain why we can factorize with a derivative ? I am about the question left unanswered in the video
@vasudevankn5752 жыл бұрын
soo much thanks mahn, been searching for this for years
@tommygaa10 жыл бұрын
at 14:34 it should be PSI* (psi star) :)
@zenojimneuromansah866511 жыл бұрын
You are excellent at explaining your mathematical reasoning. Your mini visual proof of e ^-ix multiplied with it's complex conjugate was very helpful. thanks
@jacquelinebaeza74622 жыл бұрын
I took QMI last semester and aced it. I had no idea what any of the math meant, but thanks to you know I understand what this means!! only took me 2 weeks into QMII to realize I didn't know what I was doing
@goldenchopstick178810 жыл бұрын
great explanation of probabilistic interpretation! I finally understood the relationship thanks.!
@goutham948 жыл бұрын
dear sir there is a slight mistake in the 1st term of schrodinger equation on the RHS at 6:24 Great video sir.. thank you :D
@Andrew6James4 жыл бұрын
@Brant Carlson Could you please expand on the @18:48
@StephenRayner10 жыл бұрын
What software are you using?
@dannijunglejim569211 жыл бұрын
Great explanation! Much appreciated before my exam!
@asifhossain28638 жыл бұрын
this will greatly help in my today's exam.... superb!!!!
@deconfinedQPT6 жыл бұрын
at 19:08 the reason it is true that because differentiation is a linear transformation hence superposition and homogeneity is preserved, for people who wonders as to why he was able to rewrite the expression
@executorarktanis23234 жыл бұрын
explain more is this not simple common
@universal692 жыл бұрын
The reason isn't this complex
@alexfriebe150810 жыл бұрын
would love a video on expectation values and spherical polar coordinates
@FlintPet5 ай бұрын
14:48 There is a star missing on the last blue psi for those who are confused :)
@nelsonappiagyei4713 Жыл бұрын
At 23:08 why did you not integrate from negative infinity to positive one but negative one to positive one?
@ahmed24-z2b9 ай бұрын
the epsi is zero at any intervak except this
@hidden_anonymous Жыл бұрын
Great lecture. Thank you!
@danv87184 жыл бұрын
Fantastic series! Thanks a lot for sharing
@maxmiller56569 жыл бұрын
thanks, clear and concise!
@عبدالرحمنالعصيمي-ي6ظ5 жыл бұрын
Thank billion time for this amazing video , go ahead for such amazing explanations👍🏻😩😩😩
@juanreyes856410 жыл бұрын
Hi I am having trouble understanding what you said at 5:35 that it is not posible to have a function that stays non zero or goes to infinity as x goes to infinity and still have to be integrable. If you could explain that will be great thanks.
@juanreyes856410 жыл бұрын
I think i understand: The wave function has to be zeros at both ends -infinity and pos infinity because if its not the the integral from -infinity to infinity will not be 1 thefore the wave function is non-normalizable.
@jonnyyy9716 Жыл бұрын
If the wave function satisfies the conditions for normalisation does it suffice to differentiate the integral of psi squared dx = 1 wrt time? And then the RHS goes to 0?
@stijndhondt96118 жыл бұрын
This is golden. Thanks alot!
@RI-xt4nh8 жыл бұрын
Didn't know Eric Foreman taught quantum mechanics.
@RICHFRVR4 жыл бұрын
Haha
@kimyongtan38187 жыл бұрын
Brant Carlson, May I know why 18:48 is true?
@RaveSlave2DaGrave7 жыл бұрын
late but just take the derivative using product rule, some of the terms cancel out leaving you with the equation Brant left
@Andrew6James4 жыл бұрын
@@RaveSlave2DaGrave Can you be more specific please?
@TheBrazilianFury3 жыл бұрын
@@RaveSlave2DaGrave thanks!!
@richroylance46306 жыл бұрын
Excellent lecture...thank you.
@dannijunglejim569211 жыл бұрын
At around 13:30 You divide the Schrödinger equation by ih, and the way I would have computed that, the i would have stayed next to (2m), however you have placed it as if you were multiplying the equation by i. I also am unsure of what happened to the negative symbol in that step. Could you please explain the reasoning behind these steps?
@weisun1843 жыл бұрын
This is my mom’s account but I think he multiplied by i on both side. On the left side of the shrodinger eqn you would have i^2 = -1 and hence the signs are flipped.
@gibsonmaglasang7 жыл бұрын
thank you so much prof. carlson. i learned a lot from your lecture videos. do you have lec videos on many particle physics or quantum field? thanks :)
@mkminerals123438 жыл бұрын
dear,i m confused here,once you said that infinite square amplitudes are not normalizablet,right,as in dirac delta function,/////then you fit this idea to integral(summation) of infinite basis. as we know that square integrable functions converges in hilbert space in h2 space,i.e in infinite basis. so normalizable.
@kharonofficial9 жыл бұрын
What calculus you talked when you solved the integral?
@gforcebreakin10 жыл бұрын
sounds like main guy from that 70s show
@lasha9711 жыл бұрын
I can't get the part when you bring up functions in 02:37 how can probability be negative? sigh represents probability of finding a particle in some point of x right? well how can it be negative?
@magtutorial36064 жыл бұрын
That's probability density psi(x) Not probability psi(x)2
@sacha79582 жыл бұрын
I'm pretty sure that the normalization constant at the end could also have been MINUS the square root of 15/16.
@thewalesj8972 жыл бұрын
Brilliant!
@nashtrojan11 жыл бұрын
great video.
@compphysgeek5 жыл бұрын
I dont know who the first person was to put arrows on graphs but that person deserves some sort of punishment
@reimalm71919 жыл бұрын
hi, can the constant be a negative value
@niemandwirklich6 жыл бұрын
I was asking myself the same question - mathematically yes, but would it make sense for a wave function having a negative sign? I think so, yes, but I could be wrong...
@Dekoherence-ii8pw Жыл бұрын
The wave function has a real and an imaginary part. Both of those parts are a wave which oscillate between positive and negative. If you multiply the wave function by -1 you just change the phase of the wave by 180 degrees (pi radians). @@niemandwirklich
@Dekoherence-ii8pw Жыл бұрын
If the constant is (for example) -3.5, then positive 3.5 would work just as well. The sign of the constant doesn't make a difference, because we're interested only in the square of the absolute value.
@muhammadziaulislamarsalan13928 жыл бұрын
thank u sir...
@a1ang0r858 жыл бұрын
can anyone show the step for 22:00?
@cellerism8 жыл бұрын
That is the most simple way of expressing it. u cant get anything more simpler. Its just like x^2=x(x) or u can say x^2+x^2=x(x+x)
@executorarktanis23234 жыл бұрын
@@cellerism pls help is it just that he took partial dx common or something big i missed
@AlchemistOfNirnroot6 жыл бұрын
wrt the derivative of the partial derivative of psi*, why isnt +(iV/h-bar)psi not psi star?