Redefining “physics” package vector differential operators

The physics package defines commands such as \grad, \div and \curl so that any subsequent delimiters are automatically resized (see MWE below). However, they also use a bold nabla. I would like to redefine the commands such that the automatic resizing is preserved but using a regular nabla. Is there any way this is possible?

\documentclass{article}
\usepackage{physics}

\begin{document}

$\nabla(\frac{a}{b})$
$\grad(\frac{a}{b})$

\end{document}


\documentclass{article}
$\nabla(\frac{a}{b})$
$\grad(\frac{a}{b})$