LuaLaTeX sans serif math font unicode greek

Question

I know there are a lot of posts about this here on tex.stackexchange but all I can find are pretty old (almost ~ 5-10 years old by now) and I'm not sure if they still apply.

So is there a way to use a sans serif font for the normal text characters in math mode?

\documentclass{scrartcl}
\usepackage{fontspec}
\renewcommand{\familydefault}{\sfdefault}
\usepackage{amsmath}
\usepackage[math-style=ISO]{unicode-math}
\setmathfont{Latin Modern Math}
\setmathfont{Latin Modern Math}[version=bold,FakeBold={3}]
\setoperatorfont\mathsf
\begin{document}
    normal text
$(a+\rho_i)^2 = a^2 + 2a\rho_i \rho_i^2 \quad \min\text{ text in math}$

\end{document}

In this example it would be an issue for the i indices and the a variable.

Answer 1

To get a sans serif font you should set a sans serif font; Latin Modern isn't. You need a font with math support. See: Which OpenType Math fonts are available?.

For example, with FiraMath-Regular:

\documentclass{scrartcl}
\usepackage{fontspec}
\renewcommand{\familydefault}{\sfdefault}
\usepackage{amsmath}
\usepackage[math-style=ISO]{unicode-math}
\setoperatorfont\symup
\setmathfont{FiraMath-Regular}
\begin{document}
    normal text
$(a+\rho_i)^2 = a^2 + 2a\rho_i \rho_i^2 \quad \min\text{ text in math}$


\end{document}

This gives:

I set \setoperatorfont\symup to handle operator (like \min) with unicode-math.

Answer 2

Set any OpenType math font using unicode-math. it’s the simplest way.

The unicode-math package also lets you take Greek letters from another font with, e.g. \setmathfont[range=it/{Greek, greek}]{CMU Sans Serif Italic}, but all OpenType math fonts support Greek.

There are also solutions using mathastext and mathspec, or you could load fontspec over any legacy 8-bit sans-serif math package.