- #1
rasko
- 6
- 0
In Sakurai's book, page 22:
[tex]|\beta><\alpha| \doteq
\left( \begin{array}{ccc}
<a^{(1)}|\beta><a^{(1)}|\alpha>^{*} & <a^{(1)}|\beta><a^{(2)}|\alpha>^{*} & \ldots \\
<a^{(2)}|\beta><a^{(1)}|\alpha>^{*} & <a^{(2)}|\beta><a^{(2)}|\alpha>^{*} & \ldots \\
\vdots & \vdots & \ddots
\end{array} \right)[/tex]
How can people get it? Following is my idea:
[tex]|\beta><\alpha|\\= |\beta> (\sum_{a'}|a'><a'|)<\alpha|\\
=\sum_{a'}(<a'|\beta>)(<\alpha|a'>) [STEP *][/tex]
then we get
[tex]\doteq(<a^{(1)}|\alpha>^{*}, <a^{(2)}|\alpha>^{*} ,\ldots)\cdot
\left( \begin{array}{c}
<a^{(1)}|\beta>\\
<a^{(2)}|\beta>\\
\vdots
\end{array} \right)[/tex]
Is the STEP* right? I'm not sure if i have understood the ruls of ket and bra.
[tex]|\beta><\alpha| \doteq
\left( \begin{array}{ccc}
<a^{(1)}|\beta><a^{(1)}|\alpha>^{*} & <a^{(1)}|\beta><a^{(2)}|\alpha>^{*} & \ldots \\
<a^{(2)}|\beta><a^{(1)}|\alpha>^{*} & <a^{(2)}|\beta><a^{(2)}|\alpha>^{*} & \ldots \\
\vdots & \vdots & \ddots
\end{array} \right)[/tex]
How can people get it? Following is my idea:
[tex]|\beta><\alpha|\\= |\beta> (\sum_{a'}|a'><a'|)<\alpha|\\
=\sum_{a'}(<a'|\beta>)(<\alpha|a'>) [STEP *][/tex]
then we get
[tex]\doteq(<a^{(1)}|\alpha>^{*}, <a^{(2)}|\alpha>^{*} ,\ldots)\cdot
\left( \begin{array}{c}
<a^{(1)}|\beta>\\
<a^{(2)}|\beta>\\
\vdots
\end{array} \right)[/tex]
Is the STEP* right? I'm not sure if i have understood the ruls of ket and bra.