# Scientific diagrams with TikZ

TikZ is the LaTeX drawing language, and it is the right tool for figures that need to be exactly right: Feynman diagrams, quantum circuits, chemical structures, and mathematical figures.

It is verbose and precise, which is the trade you are making. Nothing else here produces publication-quality output from text.

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## When to reach for one

* Papers, theses and technical notes that will also exist as LaTeX.
* Teaching material in physics, chemistry and mathematics.
* Any figure where a hand-drawn approximation would be wrong.

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## How to draw it in Capable

| **Route** | **Use when**                                                         |
| --------- | -------------------------------------------------------------------- |
| TikZ      | Always, for scientific figures. The library ecosystem is the reason. |
| draw.io   | Only when the figure is illustrative rather than exact.              |

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## A worked example

A simple quantum circuit, drawn with TikZ:

![Scientific diagrams with TikZ](https://help.gocapable.com/images/att1430749202.svg)

The source, which you can paste into a new diagram and edit:

```
\documentclass[tikz,border=6pt]{standalone}
\usetikzlibrary{quantikz}
\begin{document}
\begin{quantikz}
  \lstick{$\ket{0}$} & \gate{H} & \ctrl{1} & \qw      & \meter{} \\
  \lstick{$\ket{0}$} & \qw      & \targ{}  & \gate{X} & \meter{}
\end{quantikz}
\end{document}
```

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## A few things that catch people out

* TikZ rendering is heavier than the other languages; expect it to take longer.
* TikZ is disabled by default and has to be enabled by an administrator. See [Administration](https://help.gocapable.com/diagrams/administration.html).
* Use the right library: quantikz for circuits, tikz-feynman for Feynman diagrams, chemfig for molecules.

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## Related

[ASCII art diagramThe README diagram, rendered properly.](https://help.gocapable.com/diagrams/ascii-art-diagram.html)

[Circuit diagramComponents and connections, drawn properly.](https://help.gocapable.com/diagrams/circuit-diagram.html)

[ExamplesWorking diagrams you can copy.](https://help.gocapable.com/diagrams/examples.html)

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_Approximately right is wrong here._