Oct 16 (Fri) Section 3.2

Responsible party: Andromeda, nikif002

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Please try to include the following

Andromeda 10/16 3:00

nikif002 10/17 23:11

My notes match Andromeda's closely, so I added my thoughts and questions in italic

Main points for concluding chapter 2

Main points from 3.1

<math>\ f(x) = \sum_n c_n\psi_n</math> can be written as <math>\ f(x) ⇔\normalsize \left(\large\begin{array}{GC+23} \\c_{1}\\c_{2}\\c_{n}\end{array}\right)\ {\Large</math> where <math>\ c_n = \int f(x)*\psi_n(x) \,\mathrm dx</math>

<math>\hat{H}\psi_n(x)=E\psi_n(x),</math>

<math> \hat{H} f(x)=\hat{H} \sum_n c_n\psi_n(x)=\sum_n c_n E_n\psi_n⇔\normalsize \left(\large\begin{array}{GC+23} \\c_{1}E_{1}\\c_{2}E_{2}\\c_{n}E_{n}\end{array}\right)\ {\Large</math> where <math> \sum_n c_n E_n</math> is a constant.

<math>\hat{H} f(x)=\hat{H}\sum_n c_n\psi_n(x)=\sum_n c_n\hat{H}\psi_n(x)=\sum_n c_n E_n\psi_n</math>

Main points from 3.2

if the following quality holds, then the operator is a Herimitian <math>\int \psi(x)*Q\psi(x)\,\mathrm dx = \int (Q\psi(x))*\psi(x)\,\mathrm dx </math>.

<math>\ <\psi|Q\psi> = <Q\psi|\psi>* ,</math> and if it is real we are not changing anything by changing the order. This is an easy way to see that a real expectation value is necessary and sufficient to show that the operator is Hermitian.


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