Griffiths Quantum Mechanics Problem 3.12: Expectation Value of Position in Momentum Space

แชร์
ฝัง
  • เผยแพร่เมื่อ 3 ม.ค. 2025

ความคิดเห็น • 13

  • @hirokjkonwar8622
    @hirokjkonwar8622 3 ปีที่แล้ว +1

    Very nicely explained. Great work. Thank you very much. Subbed!

  • @commodorekitty
    @commodorekitty 6 ปีที่แล้ว

    Thank you. I still have to feel my way around Delta functions. This has been helpful. 😎

  • @porit1023
    @porit1023 ปีที่แล้ว

    Thanks a lot!

    • @porit1023
      @porit1023 10 หลายเดือนก่อน

      At 2:13 that's the position operator in the momentum basis
      At 8:28 what he did is he put the variable x inside the integration which is with respect to 'p'. And wrote the whole thing more compactly by writing
      -ihd/dp(e^ipx/h) which is infact equal to xe^ipx/h.
      Hope this helps!

  • @corneldevilliers461
    @corneldevilliers461 3 ปีที่แล้ว +1

    lifesaver :)

  • @maylobos7053
    @maylobos7053 6 ปีที่แล้ว +2

    How did the full derivative becomes partial derivative after the integration by parts?

    • @sheikhathar5322
      @sheikhathar5322 ปีที่แล้ว

      Using U. V rule

    • @helenaose
      @helenaose ปีที่แล้ว

      @@sheikhathar5322 Could you please elaborate? Which part do you say is v and which one is u? And shouldn't you end up with a sum of two terms after integration by parts? Does the boundary term vanish?

    • @sheikhathar5322
      @sheikhathar5322 ปีที่แล้ว

      ​@@helenaosedo roughly intg by parts,,you may get it,

    • @helenaose
      @helenaose ปีที่แล้ว

      @@sheikhathar5322 I didn't, that's why I asked for help 🙂

    • @helenaose
      @helenaose ปีที่แล้ว

      So for anyone doing Quantum Mechanics problems late at night - here is a little hint (I did do the integration by parts eventually): remember that the integral of a derivative of a function returns the function itself, so u = d(exp(ipx/hbar)/dp*dp and v = Phi. The boundary term does vanish

  • @muneshuppalapati4523
    @muneshuppalapati4523 6 ปีที่แล้ว +1

    It's too slow