Change the math font style

[s0vereign]

Hi is there an option to change the font used in mathmode for the whole document in the preamble? I am using the following preamble to write a thesis

\documentclass[%
  english,ngerman,%
  BCOR=6mm,cdgeometry=no,DIV=13%
]{tudscrbook}

\usepackage{isodate}
\usepackage{blindtext}


% Kodierung, Schrift und Sprache auswählen
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[english]{babel}

\deffootnote{1em}{1em}{\textsuperscript{\thefootnotemark }}
% Grafiken, Tabellen, Mathematikumgebungen
\usepackage{graphicx,xcolor}
\usepackage{tabularx}
\usepackage{amsmath,amssymb}
\DeclareMathOperator{\Tr}{tr}       % trace of a matrix
% Darstellung von Fließumgebungen
\usepackage{flafter,afterpage}
\usepackage[section]{placeins}
\usepackage[margin=8mm,font=small,labelfont=bf,format=plain]{caption}
%\usepackage[margin=8mm,font=small,labelfont=bf,format=plain]{subcaption}
\usepackage{subfig}							% fuer subfloats
%\numberwithin{equation}{chapter}
%\numberwithin{figure}{chapter}
%\numberwithin{table}{chapter}
\usepackage{dsfont}
\usepackage{lipsum}
\usepackage[normalem]{ulem}
\usepackage[square,numbers]{natbib} %[numbers,sort&compress]{natbib}
\usepackage{lmodern}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Ab hier ist Platz für eigene Ergänzungen (Pakete, Befehle, etc.)

%Zitieren
\usepackage[bookmarks=true]{hyperref} 
\hypersetup{colorlinks=true,allcolors=blue}  % blaue Verlinkungen                                       
\usepackage[english,capitalise]{cleveref}           % use capital beginning letters
\usepackage{cmap} 									% damit man Text aus dem PDF korrekt rauskopieren kann

%\usepackage{caption, booktabs}        	    % Bildunterschriften


%Quantenmechanik
\usepackage{braket}
\usepackage{float}							     
\usepackage{bm}                                  % for bold small gamma  \textbf{\gamma} -> \bm{\gamma}
\usepackage{mathtools}
% input python code
\usepackage{listings} % %https://en.wikibooks.org/wiki/LaTeX/Source_Code_Listings
\lstset{
	%basicstyle=\ttfamily,
	columns=fullflexible,
	frame=single,
	breaklines=true,
	postbreak=\mbox{\textcolor{red}{$\hookrightarrow$}\space},
}

\newcommand{\avg}[1]{\langle #1 \rangle}


\begin{document}
...
\end{document}

Now if I am trying to write mathematical statements I am presented with the following font:

I would like to change this font to the default mathmode font, but I couldn't find the option in the documentation.
How can I change this in the preamble?

[mrpiggi]

Hi,

your example is neither minimal nor gives it the output shown. The option you are looking for is cdmath=false and I am wondering, why you didn't find it as it is documented in one of the very first sections (2.1.2)

\documentclass[%
  english,ngerman,%
  cdmath=false
]{tudscrbook}

% Kodierung, Schrift und Sprache auswählen
\usepackage{iftex}
\iftutex
  \usepackage{fontspec}
\else
  \usepackage[T1]{fontenc}
\fi
\usepackage
%[english] either use global or package options, not both
{babel}

%\usepackage{cmap}% moved to kernel 2021-06-01 
% https://github.com/latex3/latex2e/issues/465

\begin{document}
$\psi$
\end{document}

[s0vereign]

Thank you very much for the quick response. I may have looked at the wrong location in the documentation for this option, since I assumed it had to do with the font types.