Dirac bra-ket notation typesetting.

[hongy...@gmail.com]

I try to figure out the correct way of inputting Dirac bra-ket notation, as noted here: <https://en.wikipedia.org/wiki/Bra%E2%80%93ket_notation>, in my LaTeX document. Currently, I tested with the following example:

<quote>
\documentclass{paper}
\usepackage{mathtools}
\usepackage{amsmath}
\begin{document}
$|a \rangle \langle a|$

$ \rvert a\rangle \langle a\lvert$
\end{document}
</quote>

It seems the above methods will generate the exact same results. But I still not so sure on it. Any hints for the preferable way to do this trick will be highly appreciated.

Regards,
HY

[Holger Schieferdecker]

You can have a look at the package "braket". Internally it uses the
notation in the first line of your example. It also provides additional
macros which adapt the size of the angles to the content inside.

Holger

[hongy...@gmail.com]

Thanks for your suggestion. I find the "braket" package from <https://ctan.org/tex-archive/macros/latex/contrib/braket>.

BTW, how can I let LaTeX print out the exact inner code used for the ultimate typesetting, instead of the real printing result seen by me?

HY

[Holger Schieferdecker]

Am 09.06.2021 um 11:44 schrieb hongy...@gmail.com:
> BTW, how can I let LaTeX print out the exact inner code used for the ultimate typesetting, instead of the real printing result seen by me?

You can use

\show\macroname
\meaning\macroname

The first outputs the definition of \macroname into the log file, the
second prints the definition in the document. Of course if the macro
internally uses other macros you need to repeat that step for them as
well. See the discussion here:

https://tex.stackexchange.com/questions/36955/display-source-for-a-command

Holger

[hongy...@gmail.com]

Thank you for this valuable info.

HY

[hongy...@gmail.com]

If so, how to recursively expand all possible definitions up to the innermost level programmatically in LaTeX?

HY