2

How does one typset this?:

Dirac bra-ket

I am trying to use this code:

\[
\left\langle
\begin{array}{ccc}
  electron \thickspace at \thickspace x \\
  photon \thickspace at \thickspace D_1
\end{array}
\right\vert
\]
  • You can highlight code in your post using back-ticks. To highlight code-blocks, either indent them by four spaces or use the {} on the gui. – Andrew Nov 4 '16 at 1:35
4

this approach, while a bit verbose, takes advantage of the fact that the braket package spaces the result nicely.

\documentclass{article}
\usepackage{amsmath}
\usepackage{braket}
\begin{document}
\[
 \Braket{
   \begin{array}{r}
     \text{electron at $x$}\\
     \text{photon at $D_1$}
   \end{array}
  |
   \begin{array}{l}
     \text{photon from $s$}\\
     \text{photon from $L$}
   \end{array}
 } % end \Braket
\]
\end{document}

output of example code

| improve this answer | |
3

With minimal changes to your MWE, here is one possibility:

\documentclass{article}
\usepackage{amsmath}
\begin{document}

\[
\left\langle
\begin{array}{@{}r|l@{}}
  \text{electron at $x$} & \text{photon from $s$}\\
  \text{photon at $D_1$} & \text{photom from $L$}
\end{array}
\right\rangle
\]

\end{document}

which produces

enter image description here

I have used the \text{...} command from the amsmath package, which is for typesetting text in math-mode. In the array environment the @{} remove the default spacing before and after the environment because I think this looks better.

However, rather than using an array environment, as you have done, I would use a tabular environment because then you don't need to use `\text{...}:

\[
\left\langle
\begin{tabular}{@{}r|l@{}}
  electron at $x$ & photon from $s$\\
  photon at $D_1$ & photom from $L$
\end{tabular}
\right\rangle
\]
| improve this answer | |

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