Same height of exponents on decorated symbols?

Question

I have the following expression:

$\overline\Theta^a \Theta^a$

which looks weird, since the exponents are at different heights. Can I move them lower/higher to match?

Answer 1

In this case, a \smash is sufficient. In other cases, you may also need a \vphantom{...} of the underlying variable.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\begin{document}
$\smash{\overline\Theta}^a \Theta^a$
\end{document}

Answer 2

I'd simply use \bar; maybe \widebar as defined below, but not \overline.

\documentclass{article}
\usepackage{amsmath}

% see https://tex.stackexchange.com/a/364929/4427
\DeclareFontFamily{U}{mathx}{}
\DeclareFontShape{U}{mathx}{m}{n}{ <-> mathx10 }{}
\DeclareSymbolFont{mathx}{U}{mathx}{m}{n}
\DeclareFontSubstitution{U}{mathx}{m}{n}
\DeclareMathAccent{\widebar}{\mathalpha}{mathx}{"73}

\newcommand{\ovTheta}{{\smash{\overline{\Theta}}}\vphantom{\Theta}}

\begin{document}

$\bar{\Theta}^a\Theta^a$

$\widebar{\Theta}^a\Theta^a$

$\ovTheta^a\Theta^a$

\end{document}