# \Braket

Used for bra-ket notation in quantum mechanics with automatically sized angle brackets.

https://texform.dev/latex/commands/Braket

## Metadata

| Field | Value |
| --- | --- |
| Topic | [Physics: bra-ket](https://texform.dev/latex/topics/physics-braket) |
| Packages | braket |
| Allowed mode | math |
| Tags |  |
| Commonality | low |
| Kind | prefix |

## Syntax

### braket

Argument specification: `m`

Used for bra-ket notation in quantum mechanics with automatically sized angle brackets.

## Examples

```latex
\Braket{\psi}
```

[Open in Playground](https://play.texform.dev/?input=%5CBraket%7B%5Cpsi%7D)

```latex
\Braket{\psi | \frac{1}{2} | \phi}
```

[Open in Playground](https://play.texform.dev/?input=%5CBraket%7B%5Cpsi+%7C+%5Cfrac%7B1%7D%7B2%7D+%7C+%5Cphi%7D)

## Renderer support

| Package | MathJax | KaTeX | XeTeX |
| --- | --- | --- | --- |
| braket | full | full | none |

## In TeXForm

TeXForm parses this entry as prefix syntax; the package determines its argument specification.

## See also

- [\\braket](https://texform.dev/latex/commands/braket)
- [\\set](https://texform.dev/latex/commands/set)
- [\\Set](https://texform.dev/latex/commands/Set)

## Test cases

### braket

| Input | Case | MathJax | KaTeX | XeTeX |
| --- | --- | --- | --- | --- |
| \Braket{a} | Positive: baseline | Pass | Pass | Fail |
| \Braket a | Positive: bare[0] | Pass | Pass | Fail |