Strange behaviour of widetilde in integrals

Question

I saw a lot of question related to the "widetilde" commands and the different ways to extend its definition to apply it to large strings of characters, but nothing precisely matching my problem. Please forgive me if this question was already asked.

If I to use the command \widetilde on the symbol \gamma, I obtain \widetilde{\gamma} with correct vertical spacing. However, if now I want to use it in an integral, I obtain if I want to integrate (say) some 1-form \alpha

\documentclass[10pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[english]{babel}
\usepackage{lmodern}
\usepackage{amsmath,amsfonts}

\begin{document}

$\widetilde{\gamma}$
\begin{align*}
\int_{\widetilde{\gamma}}^{}\alpha
\end{align*}

\end{document}

and the spacing between \gamma and the tilde is way too large.

Questions: Can I fix it, or should I avoid using this command?

Answer 1

It's an outstanding bug in lmodern which, in my opinion makes the fonts out of the question when “hard” mathematics is used in a document.

\documentclass[10pt,a4paper]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\usepackage{amsmath,amsfonts}

\usepackage{lmodern}

% declare `cmex` to be arbitrary scalable,
% see http://tex.stackexchange.com/a/282919/4427
\DeclareFontShape{OMX}{cmex}{m}{n}{
  <-7.5> cmex7
  <7.5-8.5> cmex8
  <8.5-9.5> cmex9
  <9.5-> cmex10
}{}
\SetSymbolFont{largesymbols}{normal}{OMX}{cmex}{m}{n}
\SetSymbolFont{largesymbols}{bold}  {OMX}{cmex}{m}{n}
% end of fix

\begin{document}

\begin{equation}
\widetilde{\gamma}-\int_{\widetilde{\gamma}}\alpha
\end{equation}

\end{document}

The output without the fix (clearly unacceptable):