# [texhax] shift subscript without superscript

Arno Trautmann Arno.Trautmann at gmx.de
Fri Jun 10 13:09:46 CEST 2016

Hi all,

this is a question that bugged me for a long time but I never dared to
ask, nor did I find discussions of this so far. Consider the simple
document:

\documentclass{minimal}
\begin{document}
$a_i a_i^\dagger + b_i b_i^\dagger$
$a_i^{} a_i^\dagger + b_i^{\strut} b_i^\dagger$
\end{document}

The first line is the normal input, and operators like this are used
frequently in quantum physics. The disturbing point are the subscripts
which are shifted further down if there is a superscript. I'm aware that
this is a nice feature normally, but in this case I would like to see
them at the same height.
In the second line of the example, the expression with the b operators
shows the desired result, while the expressions with a operators show
the three different positions of the subscript.
It is not very practical to add the ^{\strut} for every occurance –
especially if you think of a document a colleague wrote and there are
hundreds of these. Also, the \strut here causes too much space due to
its excess height.

So, finally the question: Is it possible to default the subscript of any
expression to be at the lowest position? (And, vice versa for the
superscript to be at the topmost position?) I'll happily appreciate TeX
hackery, package solutions, or Lua code … whatever helps :)

Best,
Arno