Free particle wave packets and stationary states

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  • Опубліковано 10 січ 2025

КОМЕНТАРІ • 30

  • @xXxBladeStormxXx
    @xXxBladeStormxXx 10 років тому +9

    Absolutely beautiful exposition of Group and Phase velocity! Those slanted lines were great!

  • @OmnipotentO
    @OmnipotentO 3 роки тому +2

    I believe I heard it from the Leonard Suskind lectures about how classical physics is what emerges when you take the collective averages into consideration. and you kind of demonstrated that here with the k bar at 30:30. Amazing.

  • @ishkool8664
    @ishkool8664 3 роки тому +2

    Check your understanding:
    1) False: for k

  • @Gismho
    @Gismho 3 роки тому

    Yet another superb video. This is a really interesting series, very well explained and described. Thank you professor once again.

  • @the-fantabulous-g
    @the-fantabulous-g 4 роки тому +4

    18:25 Check your understanding: I simplified my answer down to (1/(2*sqrt(pi * a))) * (ike^(ika) - ike^(-ika)).
    35:45 Check your understanding: All false, but that's a Hail Mary from me. I have no idea about this part, I'll appreciate anyone who can explain (for me and those who come after).
    Let me know if anyone differs in answers, thanks!

    • @the-fantabulous-g
      @the-fantabulous-g 4 роки тому

      For 18:25 we can probably apply a trig identity. It looks possible at least.

    • @pixelberrychoicespodcast5861
      @pixelberrychoicespodcast5861 3 роки тому

      I got something similar to that the first one I mean phi k

    • @stopwatcher8930
      @stopwatcher8930 Рік тому +1

      The first one looks more like a derivative. When you integrate e^-ikx you have to pull out -ik out of the 1 in front of the e. So basically (-1/ik)*e^-ikx.

  • @HT-rq5pi
    @HT-rq5pi 9 років тому +14

    what is the answer to the "check your understanding" qst. Its pretty hard to check ones understanding not knowing the answer.

    • @philandros3195
      @philandros3195 8 років тому +5

      Ye, that's the one short coming of these videos.. he didn't upload the answers anywhere accessible to people.

    • @manishsingh-vk8if
      @manishsingh-vk8if 5 років тому

      May be he doesnt know the answers.

  • @xXxBladeStormxXx
    @xXxBladeStormxXx 10 років тому +16

    Did I just watch a twisted derivation of the Fourier Transform? :O

    • @shavuklia7731
      @shavuklia7731 7 років тому +2

      Twisted but effective!

    • @nickolasconnor3661
      @nickolasconnor3661 3 роки тому

      i guess I am kinda off topic but do anyone know a good site to stream newly released series online ?

    • @brendanxzavier3649
      @brendanxzavier3649 3 роки тому

      @Nickolas Connor try FlixZone. You can find it by googling :)

    • @abbacle
      @abbacle 2 роки тому

      @@brendanxzavier3649 you arent fooling anyone

  • @timetraveller1237
    @timetraveller1237 8 років тому +2

    excellent work about group velocity and phase velocity understood it at right the last animation thanks so much

  • @obaidurrehman2464
    @obaidurrehman2464 3 роки тому

    Thanks ...
    I really liked the introduction of wave packet ....

  • @ramasatya6317
    @ramasatya6317 4 роки тому +1

    Thank you very much!! beautifully explained.

  • @hershyfishman2929
    @hershyfishman2929 3 роки тому

    28:24 that should have a t (as corrected later at 30:12)

  • @solsticetwo3476
    @solsticetwo3476 5 років тому +1

    Great course! Thanks a lot man

  • @princeistalri7944
    @princeistalri7944 8 років тому +1

    Why did you assume k_1 is approximately equal to k_2 at the end there? What would happen if you assumed the difference between k_1 and k_2 is arbitrary?

    • @Kraflyn
      @Kraflyn 8 років тому +4

      Hi. If k1 and k2 are far apart, the calculations are the same, the result is the same, but the animation is more "fuzzy", the animation wouldn't be so "neat". Cheers :D

  • @shahadas907
    @shahadas907 2 роки тому

    Many thanks! it helps me a lot :D

  • @titimilidbz
    @titimilidbz 4 роки тому +5

    21:54 Quantum Mechanics in a nutshell

  • @assemafanah8622
    @assemafanah8622 8 років тому +1

    thanx a lot :)

  • @huanghan1911
    @huanghan1911 6 років тому +3

    There is a mistake: Integrate(exp(ikx) exp(-Ik'x))=2 Pi delta(k-k'), not just delta(k-k')

    • @axelarnone155
      @axelarnone155 6 років тому +1

      Could you point out where in the video?

    • @huanghan1911
      @huanghan1911 6 років тому +1

      Axel Arnone 12:22

  • @manishsingh-vk8if
    @manishsingh-vk8if 5 років тому +1

    Seriously this person is very confusing.