There are so many quantum-related posts that do not use the $\LaTeX$ commands for the Bra and Ket in Diract notation.
I see a lot of this: $$ | \psi > , \quad <n|n>, \quad <E_m|H|E_n>,$$ instead of this:
$$ | \psi \rangle, \quad \langle n|n \rangle, \quad \langle E_m|H|E_n \rangle.$$
I guess I am the weird one, but when I see stuff like that I get the same feeling as when I see these pictures.
If someone is already using TeX commands to write maths, the use of ">" instead of "$\rangle$", it's either because they're taking a shortcut to avoid typing out the command, or because they don't know it exists. The former could be addressed by introducing a shorthand command like \r
for \rangle
, while the latter could be addressed by having a warning/suggestion message pop up when the question uses ">" and "<" more than (say) twice in the same row.
\left<
and\right>
are actually slightly nicer than\langle
and\rangle
, since the former get taller when they enclose complicated expressions. $\endgroup$ – rob♦ May 3 '20 at 4:10